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| <div class="TITLEPAGE"> |
| <h1 class="TITLE"><a name="AEN2" id="AEN2">NCURSES Programming |
| HOWTO</a></h1> |
| <h3 class="AUTHOR"><a name="AEN4" id="AEN4">Pradeep Padala</a></h3> |
| <div class="AFFILIATION"> |
| <div class="ADDRESS"> |
| <p class="ADDRESS"><code class="EMAIL"><<a href= |
| "mailto:ppadala@gmail.com">ppadala@gmail.com</a>></code></p> |
| </div> |
| </div> |
| <p class="PUBDATE">v1.9, 2005-06-20<br></p> |
| <div class="REVHISTORY"> |
| <table width="100%" border="0"> |
| <tr> |
| <th align="left" valign="top" colspan="3"><b>Revision |
| History</b></th> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.9</td> |
| <td align="left">2005-06-20</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">The license has been changed to the |
| MIT-style license used by NCURSES. Note that the programs are also |
| re-licensed under this.</td> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.8</td> |
| <td align="left">2005-06-17</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">Lots of updates. Added references and |
| perl examples. Changes to examples. Many grammatical and stylistic |
| changes to the content. Changes to NCURSES history.</td> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.7.1</td> |
| <td align="left">2002-06-25</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">Added a README file for building and |
| instructions for building from source.</td> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.7</td> |
| <td align="left">2002-06-25</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">Added "Other formats" section and made |
| a lot of fancy changes to the programs. Inlining of programs is |
| gone.</td> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.6.1</td> |
| <td align="left">2002-02-24</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">Removed the old Changelog section, |
| cleaned the makefiles</td> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.6</td> |
| <td align="left">2002-02-16</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">Corrected a lot of spelling mistakes, |
| added ACS variables section</td> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.5</td> |
| <td align="left">2002-01-05</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">Changed structure to present proper |
| TOC</td> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.3.1</td> |
| <td align="left">2001-07-26</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">Corrected maintainers paragraph, |
| Corrected stable release number</td> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.3</td> |
| <td align="left">2001-07-24</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">Added copyright notices to main |
| document (LDP license) and programs (GPL), Corrected |
| printw_example.</td> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.2</td> |
| <td align="left">2001-06-05</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">Incorporated ravi's changes. Mainly to |
| introduction, menu, form, justforfun sections</td> |
| </tr> |
| <tr> |
| <td align="left">Revision 1.1</td> |
| <td align="left">2001-05-22</td> |
| <td align="left">Revised by: ppadala</td> |
| </tr> |
| <tr> |
| <td align="left" colspan="3">Added "a word about window" section, |
| Added scanw_example.</td> |
| </tr> |
| </table> |
| </div> |
| <div> |
| <div class="ABSTRACT"><a name="AEN67" id="AEN67"></a> |
| <p><em>This document is intended to be an "All in One" guide for |
| programming with ncurses and its sister libraries. We graduate from |
| a simple "Hello World" program to more complex form manipulation. |
| No prior experience in ncurses is assumed. Send comments to |
| <a href="mailto:ppadala@gmail.com" target="_top">this |
| address</a></em></p> |
| </div> |
| </div> |
| <hr></div> |
| <div class="TOC"> |
| <dl> |
| <dt><b>Table of Contents</b></dt> |
| <dt>1. <a href="#INTRO">Introduction</a></dt> |
| <dd> |
| <dl> |
| <dt>1.1. <a href="#WHATIS">What is NCURSES?</a></dt> |
| <dt>1.2. <a href="#WHATCANWEDO">What we can do with |
| NCURSES</a></dt> |
| <dt>1.3. <a href="#WHERETOGETIT">Where to get it</a></dt> |
| <dt>1.4. <a href="#PURPOSE">Purpose/Scope of the document</a></dt> |
| <dt>1.5. <a href="#ABOUTPROGRAMS">About the Programs</a></dt> |
| <dt>1.6. <a href="#OTHERFORMATS">Other Formats of the |
| document</a></dt> |
| <dt>1.7. <a href="#CREDITS">Credits</a></dt> |
| <dt>1.8. <a href="#WISHLIST">Wish List</a></dt> |
| <dt>1.9. <a href="#COPYRIGHT">Copyright</a></dt> |
| </dl> |
| </dd> |
| <dt>2. <a href="#HELLOWORLD">Hello World !!!</a></dt> |
| <dd> |
| <dl> |
| <dt>2.1. <a href="#COMPILECURSES">Compiling With the NCURSES |
| Library</a></dt> |
| <dt>2.2. <a href="#DISSECTION">Dissection</a></dt> |
| </dl> |
| </dd> |
| <dt>3. <a href="#GORY">The Gory Details</a></dt> |
| <dt>4. <a href="#INIT">Initialization</a></dt> |
| <dd> |
| <dl> |
| <dt>4.1. <a href="#ABOUTINIT">Initialization functions</a></dt> |
| <dt>4.2. <a href="#RAWCBREAK">raw() and cbreak()</a></dt> |
| <dt>4.3. <a href="#ECHONOECHO">echo() and noecho()</a></dt> |
| <dt>4.4. <a href="#KEYPAD">keypad()</a></dt> |
| <dt>4.5. <a href="#HALFDELAY">halfdelay()</a></dt> |
| <dt>4.6. <a href="#MISCINIT">Miscellaneous Initialization |
| functions</a></dt> |
| <dt>4.7. <a href="#INITEX">An Example</a></dt> |
| </dl> |
| </dd> |
| <dt>5. <a href="#AWORDWINDOWS">A Word about Windows</a></dt> |
| <dt>6. <a href="#PRINTW">Output functions</a></dt> |
| <dd> |
| <dl> |
| <dt>6.1. <a href="#ADDCHCLASS">addch() class of functions</a></dt> |
| <dt>6.2. <a href="#AEN298">mvaddch(), waddch() and |
| mvwaddch()</a></dt> |
| <dt>6.3. <a href="#PRINTWCLASS">printw() class of |
| functions</a></dt> |
| <dt>6.4. <a href="#ADDSTRCLASS">addstr() class of |
| functions</a></dt> |
| <dt>6.5. <a href="#ACAUTION">A word of caution</a></dt> |
| </dl> |
| </dd> |
| <dt>7. <a href="#SCANW">Input functions</a></dt> |
| <dd> |
| <dl> |
| <dt>7.1. <a href="#GETCHCLASS">getch() class of functions</a></dt> |
| <dt>7.2. <a href="#SCANWCLASS">scanw() class of functions</a></dt> |
| <dt>7.3. <a href="#GETSTRCLASS">getstr() class of |
| functions</a></dt> |
| <dt>7.4. <a href="#GETSTREX">Some examples</a></dt> |
| </dl> |
| </dd> |
| <dt>8. <a href="#ATTRIB">Attributes</a></dt> |
| <dd> |
| <dl> |
| <dt>8.1. <a href="#ATTRIBDETAILS">The details</a></dt> |
| <dt>8.2. <a href="#ATTRONVSATTRSET">attron() vs attrset()</a></dt> |
| <dt>8.3. <a href="#ATTR_GET">attr_get()</a></dt> |
| <dt>8.4. <a href="#ATTR_FUNCS">attr_ functions</a></dt> |
| <dt>8.5. <a href="#WATTRFUNCS">wattr functions</a></dt> |
| <dt>8.6. <a href="#CHGAT">chgat() functions</a></dt> |
| </dl> |
| </dd> |
| <dt>9. <a href="#WINDOWS">Windows</a></dt> |
| <dd> |
| <dl> |
| <dt>9.1. <a href="#WINDOWBASICS">The basics</a></dt> |
| <dt>9.2. <a href="#LETBEWINDOW">Let there be a Window !!!</a></dt> |
| <dt>9.3. <a href="#BORDEREXEXPL">Explanation</a></dt> |
| <dt>9.4. <a href="#OTHERSTUFF">The other stuff in the |
| example</a></dt> |
| <dt>9.5. <a href="#OTHERBORDERFUNCS">Other Border |
| functions</a></dt> |
| </dl> |
| </dd> |
| <dt>10. <a href="#COLOR">Colors</a></dt> |
| <dd> |
| <dl> |
| <dt>10.1. <a href="#COLORBASICS">The basics</a></dt> |
| <dt>10.2. <a href="#CHANGECOLORDEFS">Changing Color |
| Definitions</a></dt> |
| <dt>10.3. <a href="#COLORCONTENT">Color Content</a></dt> |
| </dl> |
| </dd> |
| <dt>11. <a href="#KEYS">Interfacing with the key board</a></dt> |
| <dd> |
| <dl> |
| <dt>11.1. <a href="#KEYSBASICS">The Basics</a></dt> |
| <dt>11.2. <a href="#SIMPLEKEYEX">A Simple Key Usage |
| example</a></dt> |
| </dl> |
| </dd> |
| <dt>12. <a href="#MOUSE">Interfacing with the mouse</a></dt> |
| <dd> |
| <dl> |
| <dt>12.1. <a href="#MOUSEBASICS">The Basics</a></dt> |
| <dt>12.2. <a href="#GETTINGEVENTS">Getting the events</a></dt> |
| <dt>12.3. <a href="#MOUSETOGETHER">Putting it all Together</a></dt> |
| <dt>12.4. <a href="#MISCMOUSEFUNCS">Miscellaneous |
| Functions</a></dt> |
| </dl> |
| </dd> |
| <dt>13. <a href="#SCREEN">Screen Manipulation</a></dt> |
| <dd> |
| <dl> |
| <dt>13.1. <a href="#GETYX">getyx() functions</a></dt> |
| <dt>13.2. <a href="#SCREENDUMP">Screen Dumping</a></dt> |
| <dt>13.3. <a href="#WINDOWDUMP">Window Dumping</a></dt> |
| </dl> |
| </dd> |
| <dt>14. <a href="#MISC">Miscellaneous features</a></dt> |
| <dd> |
| <dl> |
| <dt>14.1. <a href="#CURSSET">curs_set()</a></dt> |
| <dt>14.2. <a href="#TEMPLEAVE">Temporarily Leaving Curses |
| mode</a></dt> |
| <dt>14.3. <a href="#ACSVARS">ACS_ variables</a></dt> |
| </dl> |
| </dd> |
| <dt>15. <a href="#OTHERLIB">Other libraries</a></dt> |
| <dt>16. <a href="#PANELS">Panel Library</a></dt> |
| <dd> |
| <dl> |
| <dt>16.1. <a href="#PANELBASICS">The Basics</a></dt> |
| <dt>16.2. <a href="#COMPILEPANELS">Compiling With the Panels |
| Library</a></dt> |
| <dt>16.3. <a href="#PANELBROWSING">Panel Window Browsing</a></dt> |
| <dt>16.4. <a href="#USERPTRUSING">Using User Pointers</a></dt> |
| <dt>16.5. <a href="#PANELMOVERESIZE">Moving and Resizing |
| Panels</a></dt> |
| <dt>16.6. <a href="#PANELSHOWHIDE">Hiding and Showing |
| Panels</a></dt> |
| <dt>16.7. <a href="#PANELABOVE">panel_above() and panel_below() |
| Functions</a></dt> |
| </dl> |
| </dd> |
| <dt>17. <a href="#MENUS">Menus Library</a></dt> |
| <dd> |
| <dl> |
| <dt>17.1. <a href="#MENUBASICS">The Basics</a></dt> |
| <dt>17.2. <a href="#COMPILEMENUS">Compiling With the Menu |
| Library</a></dt> |
| <dt>17.3. <a href="#MENUDRIVER">Menu Driver: The work horse of the |
| menu system</a></dt> |
| <dt>17.4. <a href="#MENUWINDOWS">Menu Windows</a></dt> |
| <dt>17.5. <a href="#SCROLLMENUS">Scrolling Menus</a></dt> |
| <dt>17.6. <a href="#MULTICOLUMN">Multi Columnar Menus</a></dt> |
| <dt>17.7. <a href="#MULTIVALUEMENUS">Multi Valued Menus</a></dt> |
| <dt>17.8. <a href="#MENUOPT">Menu Options</a></dt> |
| <dt>17.9. <a href="#MENUUSERPTR">The useful User Pointer</a></dt> |
| </dl> |
| </dd> |
| <dt>18. <a href="#FORMS">Forms Library</a></dt> |
| <dd> |
| <dl> |
| <dt>18.1. <a href="#FORMBASICS">The Basics</a></dt> |
| <dt>18.2. <a href="#COMPILEFORMS">Compiling With the Forms |
| Library</a></dt> |
| <dt>18.3. <a href="#PLAYFIELDS">Playing with Fields</a></dt> |
| <dt>18.4. <a href="#FORMWINDOWS">Form Windows</a></dt> |
| <dt>18.5. <a href="#FILEDVALIDATE">Field Validation</a></dt> |
| <dt>18.6. <a href="#FORMDRIVER">Form Driver: The work horse of the |
| forms system</a></dt> |
| </dl> |
| </dd> |
| <dt>19. <a href="#TOOLS">Tools and Widget Libraries</a></dt> |
| <dd> |
| <dl> |
| <dt>19.1. <a href="#CDK">CDK (Curses Development Kit)</a></dt> |
| <dt>19.2. <a href="#DIALOG">The dialog</a></dt> |
| <dt>19.3. <a href="#PERLCURSES">Perl Curses Modules CURSES::FORM |
| and CURSES::WIDGETS</a></dt> |
| </dl> |
| </dd> |
| <dt>20. <a href="#JUSTFORFUN">Just For Fun !!!</a></dt> |
| <dd> |
| <dl> |
| <dt>20.1. <a href="#GAMEOFLIFE">The Game of Life</a></dt> |
| <dt>20.2. <a href="#MAGIC">Magic Square</a></dt> |
| <dt>20.3. <a href="#HANOI">Towers of Hanoi</a></dt> |
| <dt>20.4. <a href="#QUEENS">Queens Puzzle</a></dt> |
| <dt>20.5. <a href="#SHUFFLE">Shuffle</a></dt> |
| <dt>20.6. <a href="#TT">Typing Tutor</a></dt> |
| </dl> |
| </dd> |
| <dt>21. <a href="#REF">References</a></dt> |
| </dl> |
| </div> |
| <div class="SECT1"> |
| <h2 class="SECT1"><a name="INTRO" id="INTRO">1. |
| Introduction</a></h2> |
| <p>In the olden days of teletype terminals, terminals were away |
| from computers and were connected to them through serial cables. |
| The terminals could be configured by sending a series of bytes. All |
| the capabilities (such as moving the cursor to a new location, |
| erasing part of the screen, scrolling the screen, changing modes |
| etc.) of terminals could be accessed through these series of bytes. |
| These control seeuqnces are usually called escape sequences, |
| because they start with an escape(0x1B) character. Even today, with |
| proper emulation, we can send escape sequences to the emulator and |
| achieve the same effect on a terminal window.</p> |
| <p>Suppose you wanted to print a line in color. Try typing this on |
| your console.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000">echo "^[[0;31;40mIn Color"</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The first character is an escape character, which looks like two |
| characters ^ and [. To be able to print it, you have to press |
| CTRL+V and then the ESC key. All the others are normal printable |
| characters. You should be able to see the string "In Color" in red. |
| It stays that way and to revert back to the original mode type |
| this.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000">echo "^[[0;37;40m"</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>Now, what do these magic characters mean? Difficult to |
| comprehend? They might even be different for different terminals. |
| So the designers of UNIX invented a mechanism named <var class= |
| "LITERAL">termcap</var>. It is a file that lists all the |
| capabilities of a particular terminal, along with the escape |
| sequences needed to achieve a particular effect. In the later |
| years, this was replaced by <var class="LITERAL">terminfo</var>. |
| Without delving too much into details, this mechanism allows |
| application programs to query the terminfo database and obtain the |
| control characters to be sent to a terminal or terminal |
| emulator.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="WHATIS" id="WHATIS">1.1. What is |
| NCURSES?</a></h3> |
| <p>You might be wondering, what the import of all this technical |
| gibberish is. In the above scenario, every application program is |
| supposed to query the terminfo and perform the necessary stuff |
| (sending control characters etc.). It soon became difficult to |
| manage this complexity and this gave birth to 'CURSES'. Curses is a |
| pun on the name "cursor optimization". The Curses library forms a |
| wrapper over working with raw terminal codes, and provides highly |
| flexible and efficient API (Application Programming Interface). It |
| provides functions to move the cursor, create windows, produce |
| colors, play with mouse etc. The application programs need not |
| worry about the underlying terminal capabilities.</p> |
| <p>So what is NCURSES? NCURSES is a clone of the original System V |
| Release 4.0 (SVr4) curses. It is a freely distributable library, |
| fully compatible with older version of curses. In short, it is a |
| library of functions that manages an application's display on |
| character-cell terminals. In the remainder of the document, the |
| terms curses and ncurses are used interchangeably.</p> |
| <p>A detailed history of NCURSES can be found in the NEWS file from |
| the source distribution. The current package is maintained by |
| <a href="mailto:dickey@his.com" target="_top">Thomas Dickey</a>. |
| You can contact the maintainers at <a href= |
| "mailto:bug-ncurses@gnu.org" target= |
| "_top">bug-ncurses@gnu.org</a>.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="WHATCANWEDO" id="WHATCANWEDO">1.2. What |
| we can do with NCURSES</a></h3> |
| <p>NCURSES not only creates a wrapper over terminal capabilities, |
| but also gives a robust framework to create nice looking UI (User |
| Interface)s in text mode. It provides functions to create windows |
| etc. Its sister libraries panel, menu and form provide an extension |
| to the basic curses library. These libraries usually come along |
| with curses. One can create applications that contain multiple |
| windows, menus, panels and forms. Windows can be managed |
| independently, can provide 'scrollability' and even can be |
| hidden.</p> |
| <p>Menus provide the user with an easy command selection option. |
| Forms allow the creation of easy-to-use data entry and display |
| windows. Panels extend the capabilities of ncurses to deal with |
| overlapping and stacked windows.</p> |
| <p>These are just some of the basic things we can do with ncurses. |
| As we move along, We will see all the capabilities of these |
| libraries.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="WHERETOGETIT" id="WHERETOGETIT">1.3. |
| Where to get it</a></h3> |
| <p>All right, now that you know what you can do with ncurses, you |
| must be rearing to get started. NCURSES is usually shipped with |
| your installation. In case you don't have the library or want to |
| compile it on your own, read on.</p> |
| <p><em>Compiling the package</em></p> |
| <p>NCURSES can be obtained from <a href= |
| "ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz" target= |
| "_top">ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz</a> or any |
| of the ftp sites mentioned in <a href= |
| "http://www.gnu.org/order/ftp.html" target= |
| "_top">http://www.gnu.org/order/ftp.html</a>.</p> |
| <p>Read the README and INSTALL files for details on to how to |
| install it. It usually involves the following operations.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"> tar zxvf ncurses<version>.tar.gz # unzip and untar the archive |
| cd ncurses<version> # cd to the directory |
| ./configure # configure the build according to your |
| # environment |
| make # make it |
| su root # become root |
| make install # install it</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p><em>Using the RPM</em></p> |
| <p>NCURSES RPM can be found and downloaded from <a href= |
| "http://rpmfind.net" target="_top">http://rpmfind.net</a> . The RPM |
| can be installed with the following command after becoming |
| root.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> rpm -i <downloaded rpm></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="PURPOSE" id="PURPOSE">1.4. Purpose/Scope |
| of the document</a></h3> |
| <p>This document is intended to be a "All in One" guide for |
| programming with ncurses and its sister libraries. We graduate from |
| a simple "Hello World" program to more complex form manipulation. |
| No prior experience in ncurses is assumed. The writing is informal, |
| but a lot of detail is provided for each of the examples.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ABOUTPROGRAMS" id="ABOUTPROGRAMS">1.5. |
| About the Programs</a></h3> |
| <p>All the programs in the document are available in zipped form |
| <a href= |
| "http://www.tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs.tar.gz" |
| target="_top">here</a>. Unzip and untar it. The directory structure |
| looks like this.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000">ncurses |
| | |
| |----> JustForFun -- just for fun programs |
| |----> basics -- basic programs |
| |----> demo -- output files go into this directory after make |
| | | |
| | |----> exe -- exe files of all example programs |
| |----> forms -- programs related to form library |
| |----> menus -- programs related to menus library |
| |----> panels -- programs related to panels library |
| |----> perl -- perl equivalents of the examples (contributed |
| | by Anuradha Ratnaweera) |
| |----> Makefile -- the top level Makefile |
| |----> README -- the top level README file. contains instructions |
| |----> COPYING -- copyright notice</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The individual directories contain the following files.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000">Description of files in each directory |
| -------------------------------------- |
| JustForFun |
| | |
| |----> hanoi.c -- The Towers of Hanoi Solver |
| |----> life.c -- The Game of Life demo |
| |----> magic.c -- An Odd Order Magic Square builder |
| |----> queens.c -- The famous N-Queens Solver |
| |----> shuffle.c -- A fun game, if you have time to kill |
| |----> tt.c -- A very trivial typing tutor |
| |
| basics |
| | |
| |----> acs_vars.c -- ACS_ variables example |
| |----> hello_world.c -- Simple "Hello World" Program |
| |----> init_func_example.c -- Initialization functions example |
| |----> key_code.c -- Shows the scan code of the key pressed |
| |----> mouse_menu.c -- A menu accessible by mouse |
| |----> other_border.c -- Shows usage of other border functions apa |
| | -- rt from box() |
| |----> printw_example.c -- A very simple printw() example |
| |----> scanw_example.c -- A very simple getstr() example |
| |----> simple_attr.c -- A program that can print a c file with |
| | -- comments in attribute |
| |----> simple_color.c -- A simple example demonstrating colors |
| |----> simple_key.c -- A menu accessible with keyboard UP, DOWN |
| | -- arrows |
| |----> temp_leave.c -- Demonstrates temporarily leaving curses mode |
| |----> win_border.c -- Shows Creation of windows and borders |
| |----> with_chgat.c -- chgat() usage example |
| |
| forms |
| | |
| |----> form_attrib.c -- Usage of field attributes |
| |----> form_options.c -- Usage of field options |
| |----> form_simple.c -- A simple form example |
| |----> form_win.c -- Demo of windows associated with forms |
| |
| menus |
| | |
| |----> menu_attrib.c -- Usage of menu attributes |
| |----> menu_item_data.c -- Usage of item_name() etc.. functions |
| |----> menu_multi_column.c -- Creates multi columnar menus |
| |----> menu_scroll.c -- Demonstrates scrolling capability of menus |
| |----> menu_simple.c -- A simple menu accessed by arrow keys |
| |----> menu_toggle.c -- Creates multi valued menus and explains |
| | -- REQ_TOGGLE_ITEM |
| |----> menu_userptr.c -- Usage of user pointer |
| |----> menu_win.c -- Demo of windows associated with menus |
| |
| panels |
| | |
| |----> panel_browse.c -- Panel browsing through tab. Usage of user |
| | -- pointer |
| |----> panel_hide.c -- Hiding and Un hiding of panels |
| |----> panel_resize.c -- Moving and resizing of panels |
| |----> panel_simple.c -- A simple panel example |
| |
| perl |
| |----> 01-10.pl -- Perl equivalents of first ten example programs</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>There is a top level Makefile included in the main directory. It |
| builds all the files and puts the ready-to-use exes in demo/exe |
| directory. You can also do selective make by going into the |
| corresponding directory. Each directory contains a README file |
| explaining the purpose of each c file in the directory.</p> |
| <p>For every example, I have included path name for the file |
| relative to the examples directory.</p> |
| <p>If you prefer browsing individual programs, point your browser |
| to <a href= |
| "http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/" |
| target= |
| "_top">http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/</a></p> |
| <p>All the programs are released under the same license that is |
| used by ncurses (MIT-style). This gives you the ability to do |
| pretty much anything other than claiming them as yours. Feel free |
| to use them in your programs as appropriate.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="OTHERFORMATS" id="OTHERFORMATS">1.6. |
| Other Formats of the document</a></h3> |
| <p>This howto is also availabe in various other formats on the |
| tldp.org site. Here are the links to other formats of this |
| document.</p> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="LISTFORMATS" id="LISTFORMATS">1.6.1. |
| Readily available formats from tldp.org</a></h4> |
| <ul> |
| <li> |
| <p><a href= |
| "http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/pdf/NCURSES-Programming-HOWTO.pdf" |
| target="_top">Acrobat PDF Format</a></p> |
| </li> |
| <li> |
| <p><a href= |
| "http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/ps/NCURSES-Programming-HOWTO.ps.gz" |
| target="_top">PostScript Format</a></p> |
| </li> |
| <li> |
| <p><a href= |
| "http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html/NCURSES-Programming-HOWTO-html.tar.gz" |
| target="_top">In Multiple HTML pages</a></p> |
| </li> |
| <li> |
| <p><a href= |
| "http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html_single/NCURSES-Programming-HOWTO.html" |
| target="_top">In One big HTML format</a></p> |
| </li> |
| </ul> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="BUILDSOURCE" id="BUILDSOURCE">1.6.2. |
| Building from source</a></h4> |
| <p>If above links are broken or if you want to experiment with sgml |
| read on.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"> Get both the source and the tar,gzipped programs, available at |
| http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/ |
| NCURSES-HOWTO/NCURSES-Programming-HOWTO.sgml |
| http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/ |
| NCURSES-HOWTO/ncurses_programs.tar.gz |
| |
| Unzip ncurses_programs.tar.gz with |
| tar zxvf ncurses_programs.tar.gz |
| |
| Use jade to create various formats. For example if you just want to create |
| the multiple html files, you would use |
| jade -t sgml -i html -d <path to docbook html stylesheet> |
| NCURSES-Programming-HOWTO.sgml |
| to get pdf, first create a single html file of the HOWTO with |
| jade -t sgml -i html -d <path to docbook html stylesheet> -V nochunks |
| NCURSES-Programming-HOWTO.sgml > NCURSES-ONE-BIG-FILE.html |
| then use htmldoc to get pdf file with |
| htmldoc --size universal -t pdf --firstpage p1 -f <output file name.pdf> |
| NCURSES-ONE-BIG-FILE.html |
| for ps, you would use |
| htmldoc --size universal -t ps --firstpage p1 -f <output file name.ps> |
| NCURSES-ONE-BIG-FILE.html</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>See <a href="http://www.tldp.org/LDP/LDP-Author-Guide/" target= |
| "_top">LDP Author guide</a> for more details. If all else failes, |
| mail me at <a href="ppadala@gmail.com" target= |
| "_top">ppadala@gmail.com</a></p> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="CREDITS" id="CREDITS">1.7. |
| Credits</a></h3> |
| <p>I thank <a href="mailto:sharath_1@usa.net" target= |
| "_top">Sharath</a> and Emre Akbas for helping me with few sections. |
| The introduction was initially written by sharath. I rewrote it |
| with few excerpts taken from his initial work. Emre helped in |
| writing printw and scanw sections.</p> |
| <p>Perl equivalents of the example programs are contributed by |
| <a href="mailto:Aratnaweera@virtusa.com" target="_top">Anuradha |
| Ratnaweera</a>.</p> |
| <p>Then comes <a href="mailto:parimi@ece.arizona.edu" target= |
| "_top">Ravi Parimi</a>, my dearest friend, who has been on this |
| project before even one line was written. He constantly bombarded |
| me with suggestions and patiently reviewed the whole text. He also |
| checked each program on Linux and Solaris.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="WISHLIST" id="WISHLIST">1.8. Wish |
| List</a></h3> |
| <p>This is the wish list, in the order of priority. If you have a |
| wish or you want to work on completing the wish, mail <a href= |
| "mailto:ppadala@gmail.com" target="_top">me</a>.</p> |
| <ul> |
| <li> |
| <p>Add examples to last parts of forms section.</p> |
| </li> |
| <li> |
| <p>Prepare a Demo showing all the programs and allow the user to |
| browse through description of each program. Let the user compile |
| and see the program in action. A dialog based interface is |
| preferred.</p> |
| </li> |
| <li> |
| <p>Add debug info. _tracef, _tracemouse stuff.</p> |
| </li> |
| <li> |
| <p>Accessing termcap, terminfo using functions provided by ncurses |
| package.</p> |
| </li> |
| <li> |
| <p>Working on two terminals simultaneously.</p> |
| </li> |
| <li> |
| <p>Add more stuff to miscellaneous section.</p> |
| </li> |
| </ul> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="COPYRIGHT" id="COPYRIGHT">1.9. |
| Copyright</a></h3> |
| <p>Copyright © 2001 by Pradeep Padala.</p> |
| <p>Permission is hereby granted, free of charge, to any person |
| obtaining a copy of this software and associated documentation |
| files (the "Software"), to deal in the Software without |
| restriction, including without limitation the rights to use, copy, |
| modify, merge, publish, distribute, distribute with modifications, |
| sublicense, and/or sell copies of the Software, and to permit |
| persons to whom the Software is furnished to do so, subject to the |
| following conditions:</p> |
| <p>The above copyright notice and this permission notice shall be |
| included in all copies or substantial portions of the Software.</p> |
| <p>THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| NONINFRINGEMENT. IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE |
| LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
| ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
| CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| SOFTWARE.</p> |
| <p>Except as contained in this notice, the name(s) of the above |
| copyright holders shall not be used in advertising or otherwise to |
| promote the sale, use or other dealings in this Software without |
| prior written authorization.</p> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="HELLOWORLD" id="HELLOWORLD">2. Hello |
| World !!!</a></h2> |
| <p>Welcome to the world of curses. Before we plunge into the |
| library and look into its various features, let's write a simple |
| program and say hello to the world.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="COMPILECURSES" id="COMPILECURSES">2.1. |
| Compiling With the NCURSES Library</a></h3> |
| <p>To use ncurses library functions, you have to include ncurses.h |
| in your programs. To link the program with ncurses the flag |
| -lncurses should be added.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> #include <ncurses.h> |
| . |
| . |
| . |
| |
| compile and link: gcc <program file> -lncurses</font> |
| </pre></td> |
| </tr> |
| </table> |
| <div class="EXAMPLE"><a name="BHW" id="BHW"></a> |
| <p><b>Example 1. The Hello World !!! Program</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> |
| |
| int main() |
| { |
| initscr(); /* Start curses mode */ |
| printw("Hello World !!!"); /* Print Hello World */ |
| refresh(); /* Print it on to the real screen */ |
| getch(); /* Wait for user input */ |
| endwin(); /* End curses mode */ |
| |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="DISSECTION" id="DISSECTION">2.2. |
| Dissection</a></h3> |
| <p>The above program prints "Hello World !!!" to the screen and |
| exits. This program shows how to initialize curses and do screen |
| manipulation and end curses mode. Let's dissect it line by |
| line.</p> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="ABOUT-INITSCR" id="ABOUT-INITSCR">2.2.1. |
| About initscr()</a></h4> |
| <p>The function initscr() initializes the terminal in curses mode. |
| In some implementations, it clears the screen and presents a blank |
| screen. To do any screen manipulation using curses package this has |
| to be called first. This function initializes the curses system and |
| allocates memory for our present window (called <var class= |
| "LITERAL">stdscr</var>) and some other data-structures. Under |
| extreme cases this function might fail due to insufficient memory |
| to allocate memory for curses library's data structures.</p> |
| <p>After this is done, we can do a variety of initializations to |
| customize our curses settings. These details will be explained |
| <a href="#INIT">later</a> .</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="MYST-REFRESH" id="MYST-REFRESH">2.2.2. |
| The mysterious refresh()</a></h4> |
| <p>The next line printw prints the string "Hello World !!!" on to |
| the screen. This function is analogous to normal printf in all |
| respects except that it prints the data on a window called stdscr |
| at the current (y,x) co-ordinates. Since our present co-ordinates |
| are at 0,0 the string is printed at the left hand corner of the |
| window.</p> |
| <p>This brings us to that mysterious refresh(). Well, when we |
| called printw the data is actually written to an imaginary window, |
| which is not updated on the screen yet. The job of printw is to |
| update a few flags and data structures and write the data to a |
| buffer corresponding to stdscr. In order to show it on the screen, |
| we need to call refresh() and tell the curses system to dump the |
| contents on the screen.</p> |
| <p>The philosophy behind all this is to allow the programmer to do |
| multiple updates on the imaginary screen or windows and do a |
| refresh once all his screen update is done. refresh() checks the |
| window and updates only the portion which has been changed. This |
| improves performance and offers greater flexibility too. But, it is |
| sometimes frustrating to beginners. A common mistake committed by |
| beginners is to forget to call refresh() after they did some update |
| through printw() class of functions. I still forget to add it |
| sometimes :-)</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="ABOUT-ENDWIN" id="ABOUT-ENDWIN">2.2.3. |
| About endwin()</a></h4> |
| <p>And finally don't forget to end the curses mode. Otherwise your |
| terminal might behave strangely after the program quits. endwin() |
| frees the memory taken by curses sub-system and its data structures |
| and puts the terminal in normal mode. This function must be called |
| after you are done with the curses mode.</p> |
| </div> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="GORY" id="GORY">3. The Gory |
| Details</a></h2> |
| <p>Now that we have seen how to write a simple curses program let's |
| get into the details. There are many functions that help customize |
| what you see on screen and many features which can be put to full |
| use.</p> |
| <p>Here we go...</p> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="INIT" id="INIT">4. |
| Initialization</a></h2> |
| <p>We now know that to initialize curses system the function |
| initscr() has to be called. There are functions which can be called |
| after this initialization to customize our curses session. We may |
| ask the curses system to set the terminal in raw mode or initialize |
| color or initialize the mouse etc.. Let's discuss some of the |
| functions that are normally called immediately after initscr();</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ABOUTINIT" id="ABOUTINIT">4.1. |
| Initialization functions</a></h3> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="RAWCBREAK" id="RAWCBREAK">4.2. raw() and |
| cbreak()</a></h3> |
| <p>Normally the terminal driver buffers the characters a user types |
| until a new line or carriage return is encountered. But most |
| programs require that the characters be available as soon as the |
| user types them. The above two functions are used to disable line |
| buffering. The difference between these two functions is in the way |
| control characters like suspend (CTRL-Z), interrupt and quit |
| (CTRL-C) are passed to the program. In the raw() mode these |
| characters are directly passed to the program without generating a |
| signal. In the <var class="LITERAL">cbreak()</var> mode these |
| control characters are interpreted as any other character by the |
| terminal driver. I personally prefer to use raw() as I can exercise |
| greater control over what the user does.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ECHONOECHO" id="ECHONOECHO">4.3. echo() |
| and noecho()</a></h3> |
| <p>These functions control the echoing of characters typed by the |
| user to the terminal. <var class="LITERAL">noecho()</var> switches |
| off echoing. The reason you might want to do this is to gain more |
| control over echoing or to suppress unnecessary echoing while |
| taking input from the user through the getch() etc. functions. Most |
| of the interactive programs call <var class= |
| "LITERAL">noecho()</var> at initialization and do the echoing of |
| characters in a controlled manner. It gives the programmer the |
| flexibility of echoing characters at any place in the window |
| without updating current (y,x) co-ordinates.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="KEYPAD" id="KEYPAD">4.4. |
| keypad()</a></h3> |
| <p>This is my favorite initialization function. It enables the |
| reading of function keys like F1, F2, arrow keys etc. Almost every |
| interactive program enables this, as arrow keys are a major part of |
| any User Interface. Do <var class="LITERAL">keypad(stdscr, |
| TRUE)</var> to enable this feature for the regular screen (stdscr). |
| You will learn more about key management in later sections of this |
| document.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="HALFDELAY" id="HALFDELAY">4.5. |
| halfdelay()</a></h3> |
| <p>This function, though not used very often, is a useful one at |
| times. halfdelay()is called to enable the half-delay mode, which is |
| similar to the cbreak() mode in that characters typed are |
| immediately available to program. However, it waits for 'X' tenths |
| of a second for input and then returns ERR, if no input is |
| available. 'X' is the timeout value passed to the function |
| halfdelay(). This function is useful when you want to ask the user |
| for input, and if he doesn't respond with in certain time, we can |
| do some thing else. One possible example is a timeout at the |
| password prompt.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MISCINIT" id="MISCINIT">4.6. |
| Miscellaneous Initialization functions</a></h3> |
| <p>There are few more functions which are called at initialization |
| to customize curses behavior. They are not used as extensively as |
| those mentioned above. Some of them are explained where |
| appropriate.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="INITEX" id="INITEX">4.7. An |
| Example</a></h3> |
| <p>Let's write a program which will clarify the usage of these |
| functions.</p> |
| <div class="EXAMPLE"><a name="BINFU" id="BINFU"></a> |
| <p><b>Example 2. Initialization Function Usage example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> |
| |
| int main() |
| { int ch; |
| |
| initscr(); /* Start curses mode */ |
| raw(); /* Line buffering disabled */ |
| keypad(stdscr, TRUE); /* We get F1, F2 etc.. */ |
| noecho(); /* Don't echo() while we do getch */ |
| |
| printw("Type any character to see it in bold\n"); |
| ch = getch(); /* If raw() hadn't been called |
| * we have to press enter before it |
| * gets to the program */ |
| if(ch == KEY_F(1)) /* Without keypad enabled this will */ |
| printw("F1 Key pressed");/* not get to us either */ |
| /* Without noecho() some ugly escape |
| * charachters might have been printed |
| * on screen */ |
| else |
| { printw("The pressed key is "); |
| attron(A_BOLD); |
| printw("%c", ch); |
| attroff(A_BOLD); |
| } |
| refresh(); /* Print it on to the real screen */ |
| getch(); /* Wait for user input */ |
| endwin(); /* End curses mode */ |
| |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>This program is self-explanatory. But I used functions which |
| aren't explained yet. The function <var class= |
| "LITERAL">getch()</var> is used to get a character from user. It is |
| equivalent to normal <var class="LITERAL">getchar()</var> except |
| that we can disable the line buffering to avoid <enter> after |
| input. Look for more about <var class="LITERAL">getch()</var>and |
| reading keys in the <a href="#KEYS">key management section</a> . |
| The functions attron and attroff are used to switch some attributes |
| on and off respectively. In the example I used them to print the |
| character in bold. These functions are explained in detail |
| later.</p> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="AWORDWINDOWS" id="AWORDWINDOWS">5. A |
| Word about Windows</a></h2> |
| <p>Before we plunge into the myriad ncurses functions, let me clear |
| few things about windows. Windows are explained in detail in |
| following <a href="#WINDOWS">sections</a></p> |
| <p>A Window is an imaginary screen defined by curses system. A |
| window does not mean a bordered window which you usually see on |
| Win9X platforms. When curses is initialized, it creates a default |
| window named <var class="LITERAL">stdscr</var> which represents |
| your 80x25 (or the size of window in which you are running) screen. |
| If you are doing simple tasks like printing few strings, reading |
| input etc., you can safely use this single window for all of your |
| purposes. You can also create windows and call functions which |
| explicitly work on the specified window.</p> |
| <p>For example, if you call</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> printw("Hi There !!!"); |
| refresh();</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>It prints the string on stdscr at the present cursor position. |
| Similarly the call to refresh(), works on stdscr only.</p> |
| <p>Say you have created <a href="#WINDOWS">windows</a> then you |
| have to call a function with a 'w' added to the usual function.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> wprintw(win, "Hi There !!!"); |
| wrefresh(win);</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>As you will see in the rest of the document, naming of functions |
| follow the same convention. For each function there usually are |
| three more functions.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"> printw(string); /* Print on stdscr at present cursor position */ |
| mvprintw(y, x, string);/* Move to (y, x) then print string */ |
| wprintw(win, string); /* Print on window win at present cursor position */ |
| /* in the window */ |
| mvwprintw(win, y, x, string); /* Move to (y, x) relative to window */ |
| /* co-ordinates and then print */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>Usually the w-less functions are macros which expand to |
| corresponding w-function with stdscr as the window parameter.</p> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="PRINTW" id="PRINTW">6. Output |
| functions</a></h2> |
| <p>I guess you can't wait any more to see some action. Back to our |
| odyssey of curses functions. Now that curses is initialized, let's |
| interact with world.</p> |
| <p>There are three classes of functions which you can use to do |
| output on screen.</p> |
| <ol type="1"> |
| <li> |
| <p>addch() class: Print single character with attributes</p> |
| </li> |
| <li> |
| <p>printw() class: Print formatted output similar to printf()</p> |
| </li> |
| <li> |
| <p>addstr() class: Print strings</p> |
| </li> |
| </ol> |
| <p>These functions can be used interchangeably and it's a matter of |
| style as to which class is used. Let's see each one in detail.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ADDCHCLASS" id="ADDCHCLASS">6.1. addch() |
| class of functions</a></h3> |
| <p>These functions put a single character into the current cursor |
| location and advance the position of the cursor. You can give the |
| character to be printed but they usually are used to print a |
| character with some attributes. Attributes are explained in detail |
| in later <a href="#ATTRIB">sections</a> of the document. If a |
| character is associated with an attribute(bold, reverse video |
| etc.), when curses prints the character, it is printed in that |
| attribute.</p> |
| <p>In order to combine a character with some attributes, you have |
| two options:</p> |
| <ul> |
| <li> |
| <p>By OR'ing a single character with the desired attribute macros. |
| These attribute macros could be found in the header file |
| <var class="LITERAL">ncurses.h</var>. For example, you want to |
| print a character ch(of type char) bold and underlined, you would |
| call addch() as below.</p> |
| <table border="0" bgcolor="#E0E0E0" width="90%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> addch(ch | A_BOLD | A_UNDERLINE);</font> |
| </pre></td> |
| </tr> |
| </table> |
| </li> |
| <li> |
| <p>By using functions like <var class= |
| "LITERAL">attrset(),attron(),attroff()</var>. These functions are |
| explained in the <a href="#ATTRIB">Attributes</a> section. Briefly, |
| they manipulate the current attributes of the given window. Once |
| set, the character printed in the window are associated with the |
| attributes until it is turned off.</p> |
| </li> |
| </ul> |
| <p>Additionally, <var class="LITERAL">curses</var> provides some |
| special characters for character-based graphics. You can draw |
| tables, horizontal or vertical lines, etc. You can find all |
| avaliable characters in the header file <var class= |
| "LITERAL">ncurses.h</var>. Try looking for macros beginning with |
| <var class="LITERAL">ACS_</var> in this file.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="AEN298" id="AEN298">6.2. mvaddch(), |
| waddch() and mvwaddch()</a></h3> |
| <p><var class="LITERAL">mvaddch()</var> is used to move the cursor |
| to a given point, and then print. Thus, the calls:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"> move(row,col); /* moves the cursor to row<em>th</em> row and col<em>th</em> column */ |
| addch(ch);</font> |
| </pre></td> |
| </tr> |
| </table> |
| can be replaced by |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> mvaddch(row,col,ch);</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p><var class="LITERAL">waddch()</var> is similar to <var class= |
| "LITERAL">addch()</var>, except that it adds a character into the |
| given window. (Note that <var class="LITERAL">addch()</var> adds a |
| character into the window <var class="LITERAL">stdscr</var>.)</p> |
| <p>In a similar fashion <var class="LITERAL">mvwaddch()</var> |
| function is used to add a character into the given window at the |
| given coordinates.</p> |
| <p>Now, we are familiar with the basic output function <var class= |
| "LITERAL">addch()</var>. But, if we want to print a string, it |
| would be very annoying to print it character by character. |
| Fortunately, <var class="LITERAL">ncurses</var> provides |
| <var class="LITERAL">printf</var><em>-like</em> or <var class= |
| "LITERAL">puts</var><em>-like</em> functions.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="PRINTWCLASS" id="PRINTWCLASS">6.3. |
| printw() class of functions</a></h3> |
| <p>These functions are similar to <var class= |
| "LITERAL">printf()</var> with the added capability of printing at |
| any position on the screen.</p> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="PRINTWMVPRINTW" id= |
| "PRINTWMVPRINTW">6.3.1. printw() and mvprintw</a></h4> |
| <p>These two functions work much like <var class= |
| "LITERAL">printf()</var>. <var class="LITERAL">mvprintw()</var> can |
| be used to move the cursor to a position and then print. If you |
| want to move the cursor first and then print using <var class= |
| "LITERAL">printw()</var> function, use <var class= |
| "LITERAL">move()</var> first and then use <var class= |
| "LITERAL">printw()</var> though I see no point why one should avoid |
| using <var class="LITERAL">mvprintw()</var>, you have the |
| flexibility to manipulate.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="WPRINTWMVWPRINTW" id= |
| "WPRINTWMVWPRINTW">6.3.2. wprintw() and mvwprintw</a></h4> |
| <p>These two functions are similar to above two except that they |
| print in the corresponding window given as argument.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="VWPRINTW" id="VWPRINTW">6.3.3. |
| vwprintw()</a></h4> |
| <p>This function is similar to <var class= |
| "LITERAL">vprintf()</var>. This can be used when variable number of |
| arguments are to be printed.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="SIMPLEPRINTWEX" id= |
| "SIMPLEPRINTWEX">6.3.4. A Simple printw example</a></h4> |
| <div class="EXAMPLE"><a name="BPREX" id="BPREX"></a> |
| <p><b>Example 3. A Simple printw example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> /* ncurses.h includes stdio.h */ |
| #include <string.h> |
| |
| int main() |
| { |
| char mesg[]="Just a string"; /* message to be appeared on the screen */ |
| int row,col; /* to store the number of rows and * |
| * the number of colums of the screen */ |
| initscr(); /* start the curses mode */ |
| getmaxyx(stdscr,row,col); /* get the number of rows and columns */ |
| mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg); |
| /* print the message at the center of the screen */ |
| mvprintw(row-2,0,"This screen has %d rows and %d columns\n",row,col); |
| printw("Try resizing your window(if possible) and then run this program again"); |
| refresh(); |
| getch(); |
| endwin(); |
| |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>Above program demonstrates how easy it is to use <var class= |
| "LITERAL">printw</var>. You just feed the coordinates and the |
| message to be appeared on the screen, then it does what you |
| want.</p> |
| <p>The above program introduces us to a new function <var class= |
| "LITERAL">getmaxyx()</var>, a macro defined in <var class= |
| "LITERAL">ncurses.h</var>. It gives the number of columns and the |
| number of rows in a given window. <var class= |
| "LITERAL">getmaxyx()</var> does this by updating the variables |
| given to it. Since <var class="LITERAL">getmaxyx()</var> is not a |
| function we don't pass pointers to it, we just give two integer |
| variables.</p> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ADDSTRCLASS" id="ADDSTRCLASS">6.4. |
| addstr() class of functions</a></h3> |
| <p><var class="LITERAL">addstr()</var> is used to put a character |
| string into a given window. This function is similar to calling |
| <var class="LITERAL">addch()</var> once for each character in a |
| given string. This is true for all output functions. There are |
| other functions from this family such as <var class= |
| "LITERAL">mvaddstr(),mvwaddstr()</var> and <var class= |
| "LITERAL">waddstr()</var>, which obey the naming convention of |
| curses.(e.g. mvaddstr() is similar to the respective calls move() |
| and then addstr().) Another function of this family is addnstr(), |
| which takes an integer parameter(say n) additionally. This function |
| puts at most n characters into the screen. If n is negative, then |
| the entire string will be added.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ACAUTION" id="ACAUTION">6.5. A word of |
| caution</a></h3> |
| <p>All these functions take y co-ordinate first and then x in their |
| arguments. A common mistake by beginners is to pass x,y in that |
| order. If you are doing too many manipulations of (y,x) |
| co-ordinates, think of dividing the screen into windows and |
| manipulate each one separately. Windows are explained in the |
| <a href="#WINDOWS">windows</a> section.</p> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="SCANW" id="SCANW">7. Input |
| functions</a></h2> |
| <p>Well, printing without taking input, is boring. Let's see |
| functions which allow us to get input from user. These functions |
| also can be divided into three categories.</p> |
| <ol type="1"> |
| <li> |
| <p>getch() class: Get a character</p> |
| </li> |
| <li> |
| <p>scanw() class: Get formatted input</p> |
| </li> |
| <li> |
| <p>getstr() class: Get strings</p> |
| </li> |
| </ol> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="GETCHCLASS" id="GETCHCLASS">7.1. getch() |
| class of functions</a></h3> |
| <p>These functions read a single character from the terminal. But |
| there are several subtle facts to consider. For example if you |
| don't use the function cbreak(), curses will not read your input |
| characters contiguously but will begin read them only after a new |
| line or an EOF is encountered. In order to avoid this, the cbreak() |
| function must used so that characters are immediately available to |
| your program. Another widely used function is noecho(). As the name |
| suggests, when this function is set (used), the characters that are |
| keyed in by the user will not show up on the screen. The two |
| functions cbreak() and noecho() are typical examples of key |
| management. Functions of this genre are explained in the <a href= |
| "#KEYS">key management section</a> .</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="SCANWCLASS" id="SCANWCLASS">7.2. scanw() |
| class of functions</a></h3> |
| <p>These functions are similar to <var class= |
| "LITERAL">scanf()</var> with the added capability of getting the |
| input from any location on the screen.</p> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="SCANWMVSCANW" id="SCANWMVSCANW">7.2.1. |
| scanw() and mvscanw</a></h4> |
| <p>The usage of these functions is similar to that of <var class= |
| "LITERAL">sscanf()</var>, where the line to be scanned is provided |
| by <var class="LITERAL">wgetstr()</var> function. That is, these |
| functions call to <var class="LITERAL">wgetstr()</var> |
| function(explained below) and uses the resulting line for a |
| scan.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="WSCANWMVWSCANW" id= |
| "WSCANWMVWSCANW">7.2.2. wscanw() and mvwscanw()</a></h4> |
| <p>These are similar to above two functions except that they read |
| from a window, which is supplied as one of the arguments to these |
| functions.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="VWSCANW" id="VWSCANW">7.2.3. |
| vwscanw()</a></h4> |
| <p>This function is similar to <var class="LITERAL">vscanf()</var>. |
| This can be used when a variable number of arguments are to be |
| scanned.</p> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="GETSTRCLASS" id="GETSTRCLASS">7.3. |
| getstr() class of functions</a></h3> |
| <p>These functions are used to get strings from the terminal. In |
| essence, this function performs the same task as would be achieved |
| by a series of calls to <var class="LITERAL">getch()</var> until a |
| newline, carriage return, or end-of-file is received. The resulting |
| string of characters are pointed to by <var class= |
| "LITERAL">str</var>, which is a character pointer provided by the |
| user.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="GETSTREX" id="GETSTREX">7.4. Some |
| examples</a></h3> |
| <div class="EXAMPLE"><a name="BSCEX" id="BSCEX"></a> |
| <p><b>Example 4. A Simple scanw example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> /* ncurses.h includes stdio.h */ |
| #include <string.h> |
| |
| int main() |
| { |
| char mesg[]="Enter a string: "; /* message to be appeared on the screen */ |
| char str[80]; |
| int row,col; /* to store the number of rows and * |
| * the number of colums of the screen */ |
| initscr(); /* start the curses mode */ |
| getmaxyx(stdscr,row,col); /* get the number of rows and columns */ |
| mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg); |
| /* print the message at the center of the screen */ |
| getstr(str); |
| mvprintw(LINES - 2, 0, "You Entered: %s", str); |
| getch(); |
| endwin(); |
| |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="ATTRIB" id="ATTRIB">8. |
| Attributes</a></h2> |
| <p>We have seen an example of how attributes can be used to print |
| characters with some special effects. Attributes, when set |
| prudently, can present information in an easy, understandable |
| manner. The following program takes a C file as input and prints |
| the file with comments in bold. Scan through the code.</p> |
| <div class="EXAMPLE"><a name="BSIAT" id="BSIAT"></a> |
| <p><b>Example 5. A Simple Attributes example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">/* pager functionality by Joseph Spainhour" <spainhou@bellsouth.net> */ |
| #include <ncurses.h> |
| #include <stdlib.h> |
| |
| int main(int argc, char *argv[]) |
| { |
| int ch, prev, row, col; |
| prev = EOF; |
| FILE *fp; |
| int y, x; |
| |
| if(argc != 2) |
| { |
| printf("Usage: %s <a c file name>\n", argv[0]); |
| exit(1); |
| } |
| fp = fopen(argv[1], "r"); |
| if(fp == NULL) |
| { |
| perror("Cannot open input file"); |
| exit(1); |
| } |
| initscr(); /* Start curses mode */ |
| getmaxyx(stdscr, row, col); /* find the boundaries of the screeen */ |
| while((ch = fgetc(fp)) != EOF) /* read the file till we reach the end */ |
| { |
| getyx(stdscr, y, x); /* get the current curser position */ |
| if(y == (row - 1)) /* are we are at the end of the screen */ |
| { |
| printw("<-Press Any Key->"); /* tell the user to press a key */ |
| getch(); |
| clear(); /* clear the screen */ |
| move(0, 0); /* start at the beginning of the screen */ |
| } |
| if(prev == '/' && ch == '*') /* If it is / and * then only |
| * switch bold on */ |
| { |
| attron(A_BOLD); /* cut bold on */ |
| getyx(stdscr, y, x); /* get the current curser position */ |
| move(y, x - 1); /* back up one space */ |
| printw("%c%c", '/', ch); /* The actual printing is done here */ |
| } |
| else |
| printw("%c", ch); |
| refresh(); |
| if(prev == '*' && ch == '/') |
| attroff(A_BOLD); /* Switch it off once we got * |
| * and then / */ |
| prev = ch; |
| } |
| endwin(); /* End curses mode */ |
| fclose(fp); |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>Don't worry about all those initialization and other crap. |
| Concentrate on the while loop. It reads each character in the file |
| and searches for the pattern /*. Once it spots the pattern, it |
| switches the BOLD attribute on with <var class= |
| "LITERAL">attron()</var> . When we get the pattern */ it is |
| switched off by <var class="LITERAL">attroff()</var> .</p> |
| <p>The above program also introduces us to two useful functions |
| <var class="LITERAL">getyx()</var> and <var class= |
| "LITERAL">move()</var>. The first function gets the co-ordinates of |
| the present cursor into the variables y, x. Since getyx() is a |
| macro we don't have to pass pointers to variables. The function |
| <var class="LITERAL">move()</var> moves the cursor to the |
| co-ordinates given to it.</p> |
| <p>The above program is really a simple one which doesn't do much. |
| On these lines one could write a more useful program which reads a |
| C file, parses it and prints it in different colors. One could even |
| extend it to other languages as well.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ATTRIBDETAILS" id="ATTRIBDETAILS">8.1. |
| The details</a></h3> |
| <p>Let's get into more details of attributes. The functions |
| <var class="LITERAL">attron(), attroff(), attrset()</var> , and |
| their sister functions <var class="LITERAL">attr_get()</var> etc.. |
| can be used to switch attributes on/off , get attributes and |
| produce a colorful display.</p> |
| <p>The functions attron and attroff take a bit-mask of attributes |
| and switch them on or off, respectively. The following video |
| attributes, which are defined in <curses.h> can be passed to |
| these functions.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> |
| A_NORMAL Normal display (no highlight) |
| A_STANDOUT Best highlighting mode of the terminal. |
| A_UNDERLINE Underlining |
| A_REVERSE Reverse video |
| A_BLINK Blinking |
| A_DIM Half bright |
| A_BOLD Extra bright or bold |
| A_PROTECT Protected mode |
| A_INVIS Invisible or blank mode |
| A_ALTCHARSET Alternate character set |
| A_CHARTEXT Bit-mask to extract a character |
| COLOR_PAIR(n) Color-pair number n |
| </font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The last one is the most colorful one :-) Colors are explained |
| in the <a href="#color" target="_top">next sections</a>.</p> |
| <p>We can OR(|) any number of above attributes to get a combined |
| effect. If you wanted reverse video with blinking characters you |
| can use</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> attron(A_REVERSE | A_BLINK);</font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ATTRONVSATTRSET" id= |
| "ATTRONVSATTRSET">8.2. attron() vs attrset()</a></h3> |
| <p>Then what is the difference between attron() and attrset()? |
| attrset sets the attributes of window whereas attron just switches |
| on the attribute given to it. So attrset() fully overrides whatever |
| attributes the window previously had and sets it to the new |
| attribute(s). Similarly attroff() just switches off the |
| attribute(s) given to it as an argument. This gives us the |
| flexibility of managing attributes easily.But if you use them |
| carelessly you may loose track of what attributes the window has |
| and garble the display. This is especially true while managing |
| menus with colors and highlighting. So decide on a consistent |
| policy and stick to it. You can always use <var class= |
| "LITERAL">standend()</var> which is equivalent to <var class= |
| "LITERAL">attrset(A_NORMAL)</var> which turns off all attributes |
| and brings you to normal mode.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ATTR_GET" id="ATTR_GET">8.3. |
| attr_get()</a></h3> |
| <p>The function attr_get() gets the current attributes and color |
| pair of the window. Though we might not use this as often as the |
| above functions, this is useful in scanning areas of screen. Say we |
| wanted to do some complex update on screen and we are not sure what |
| attribute each character is associated with. Then this function can |
| be used with either attrset or attron to produce the desired |
| effect.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ATTR_FUNCS" id="ATTR_FUNCS">8.4. attr_ |
| functions</a></h3> |
| <p>There are series of functions like attr_set(), attr_on etc.. |
| These are similar to above functions except that they take |
| parameters of type <var class="LITERAL">attr_t</var>.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="WATTRFUNCS" id="WATTRFUNCS">8.5. wattr |
| functions</a></h3> |
| <p>For each of the above functions we have a corresponding function |
| with 'w' which operates on a particular window. The above functions |
| operate on stdscr.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="CHGAT" id="CHGAT">8.6. chgat() |
| functions</a></h3> |
| <p>The function chgat() is listed in the end of the man page |
| curs_attr. It actually is a useful one. This function can be used |
| to set attributes for a group of characters without moving. I mean |
| it !!! without moving the cursor :-) It changes the attributes of a |
| given number of characters starting at the current cursor |
| location.</p> |
| <p>We can give -1 as the character count to update till end of |
| line. If you want to change attributes of characters from current |
| position to end of line, just use this.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> chgat(-1, A_REVERSE, 0, NULL);</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>This function is useful when changing attributes for characters |
| that are already on the screen. Move to the character from which |
| you want to change and change the attribute.</p> |
| <p>Other functions wchgat(), mvchgat(), wchgat() behave similarly |
| except that the w functions operate on the particular window. The |
| mv functions first move the cursor then perform the work given to |
| them. Actually chgat is a macro which is replaced by a wchgat() |
| with stdscr as the window. Most of the "w-less" functions are |
| macros.</p> |
| <div class="EXAMPLE"><a name="BWICH" id="BWICH"></a> |
| <p><b>Example 6. Chgat() Usage example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> |
| |
| int main(int argc, char *argv[]) |
| { initscr(); /* Start curses mode */ |
| start_color(); /* Start color functionality */ |
| |
| init_pair(1, COLOR_CYAN, COLOR_BLACK); |
| printw("A Big string which i didn't care to type fully "); |
| mvchgat(0, 0, -1, A_BLINK, 1, NULL); |
| /* |
| * First two parameters specify the position at which to start |
| * Third parameter number of characters to update. -1 means till |
| * end of line |
| * Forth parameter is the normal attribute you wanted to give |
| * to the charcter |
| * Fifth is the color index. It is the index given during init_pair() |
| * use 0 if you didn't want color |
| * Sixth one is always NULL |
| */ |
| refresh(); |
| getch(); |
| endwin(); /* End curses mode */ |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>This example also introduces us to the color world of curses. |
| Colors will be explained in detail later. Use 0 for no color.</p> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="WINDOWS" id="WINDOWS">9. |
| Windows</a></h2> |
| <p>Windows form the most important concept in curses. You have seen |
| the standard window stdscr above where all the functions implicitly |
| operated on this window. Now to make design even a simplest GUI, |
| you need to resort to windows. The main reason you may want to use |
| windows is to manipulate parts of the screen separately, for better |
| efficiency, by updating only the windows that need to be changed |
| and for a better design. I would say the last reason is the most |
| important in going for windows. You should always strive for a |
| better and easy-to-manage design in your programs. If you are |
| writing big, complex GUIs this is of pivotal importance before you |
| start doing anything.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="WINDOWBASICS" id="WINDOWBASICS">9.1. The |
| basics</a></h3> |
| <p>A Window can be created by calling the function <var class= |
| "LITERAL">newwin()</var>. It doesn't create any thing on the screen |
| actually. It allocates memory for a structure to manipulate the |
| window and updates the structure with data regarding the window |
| like it's size, beginy, beginx etc.. Hence in curses, a window is |
| just an abstraction of an imaginary window, which can be |
| manipulated independent of other parts of screen. The function |
| newwin() returns a pointer to structure WINDOW, which can be passed |
| to window related functions like wprintw() etc.. Finally the window |
| can be destroyed with delwin(). It will deallocate the memory |
| associated with the window structure.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="LETBEWINDOW" id="LETBEWINDOW">9.2. Let |
| there be a Window !!!</a></h3> |
| <p>What fun is it, if a window is created and we can't see it. So |
| the fun part begins by displaying the window. The function |
| <var class="LITERAL">box()</var> can be used to draw a border |
| around the window. Let's explore these functions in more detail in |
| this example.</p> |
| <div class="EXAMPLE"><a name="BWIBO" id="BWIBO"></a> |
| <p><b>Example 7. Window Border example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> |
| |
| |
| WINDOW *create_newwin(int height, int width, int starty, int startx); |
| void destroy_win(WINDOW *local_win); |
| |
| int main(int argc, char *argv[]) |
| { WINDOW *my_win; |
| int startx, starty, width, height; |
| int ch; |
| |
| initscr(); /* Start curses mode */ |
| cbreak(); /* Line buffering disabled, Pass on |
| * everty thing to me */ |
| keypad(stdscr, TRUE); /* I need that nifty F1 */ |
| |
| height = 3; |
| width = 10; |
| starty = (LINES - height) / 2; /* Calculating for a center placement */ |
| startx = (COLS - width) / 2; /* of the window */ |
| printw("Press F1 to exit"); |
| refresh(); |
| my_win = create_newwin(height, width, starty, startx); |
| |
| while((ch = getch()) != KEY_F(1)) |
| { switch(ch) |
| { case KEY_LEFT: |
| destroy_win(my_win); |
| my_win = create_newwin(height, width, starty,--startx); |
| break; |
| case KEY_RIGHT: |
| destroy_win(my_win); |
| my_win = create_newwin(height, width, starty,++startx); |
| break; |
| case KEY_UP: |
| destroy_win(my_win); |
| my_win = create_newwin(height, width, --starty,startx); |
| break; |
| case KEY_DOWN: |
| destroy_win(my_win); |
| my_win = create_newwin(height, width, ++starty,startx); |
| break; |
| } |
| } |
| |
| endwin(); /* End curses mode */ |
| return 0; |
| } |
| |
| WINDOW *create_newwin(int height, int width, int starty, int startx) |
| { WINDOW *local_win; |
| |
| local_win = newwin(height, width, starty, startx); |
| box(local_win, 0 , 0); /* 0, 0 gives default characters |
| * for the vertical and horizontal |
| * lines */ |
| wrefresh(local_win); /* Show that box */ |
| |
| return local_win; |
| } |
| |
| void destroy_win(WINDOW *local_win) |
| { |
| /* box(local_win, ' ', ' '); : This won't produce the desired |
| * result of erasing the window. It will leave it's four corners |
| * and so an ugly remnant of window. |
| */ |
| wborder(local_win, ' ', ' ', ' ',' ',' ',' ',' ',' '); |
| /* The parameters taken are |
| * 1. win: the window on which to operate |
| * 2. ls: character to be used for the left side of the window |
| * 3. rs: character to be used for the right side of the window |
| * 4. ts: character to be used for the top side of the window |
| * 5. bs: character to be used for the bottom side of the window |
| * 6. tl: character to be used for the top left corner of the window |
| * 7. tr: character to be used for the top right corner of the window |
| * 8. bl: character to be used for the bottom left corner of the window |
| * 9. br: character to be used for the bottom right corner of the window |
| */ |
| wrefresh(local_win); |
| delwin(local_win); |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="BORDEREXEXPL" id="BORDEREXEXPL">9.3. |
| Explanation</a></h3> |
| <p>Don't scream. I know it's a big example. But I have to explain |
| some important things here :-). This program creates a rectangular |
| window that can be moved with left, right, up, down arrow keys. It |
| repeatedly creates and destroys windows as user press a key. Don't |
| go beyond the screen limits. Checking for those limits is left as |
| an exercise for the reader. Let's dissect it by line by line.</p> |
| <p>The <var class="LITERAL">create_newwin()</var> function creates |
| a window with <var class="LITERAL">newwin()</var> and displays a |
| border around it with box. The function <var class= |
| "LITERAL">destroy_win()</var> first erases the window from screen |
| by painting a border with ' ' character and then calling |
| <var class="LITERAL">delwin()</var> to deallocate memory related to |
| it. Depending on the key the user presses, starty or startx is |
| changed and a new window is created.</p> |
| <p>In the destroy_win, as you can see, I used wborder instead of |
| box. The reason is written in the comments (You missed it. I know. |
| Read the code :-)). wborder draws a border around the window with |
| the characters given to it as the 4 corner points and the 4 lines. |
| To put it clearly, if you have called wborder as below:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"> wborder(win, '|', '|', '-', '-', '+', '+', '+', '+');</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>it produces some thing like</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> +------------+ |
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
| +------------+</font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="OTHERSTUFF" id="OTHERSTUFF">9.4. The |
| other stuff in the example</a></h3> |
| <p>You can also see in the above examples, that I have used the |
| variables COLS, LINES which are initialized to the screen sizes |
| after initscr(). They can be useful in finding screen dimensions |
| and finding the center co-ordinate of the screen as above. The |
| function <var class="LITERAL">getch()</var> as usual gets the key |
| from keyboard and according to the key it does the corresponding |
| work. This type of switch- case is very common in any GUI based |
| programs.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="OTHERBORDERFUNCS" id= |
| "OTHERBORDERFUNCS">9.5. Other Border functions</a></h3> |
| <p>Above program is grossly inefficient in that with each press of |
| a key, a window is destroyed and another is created. So let's write |
| a more efficient program which uses other border related |
| functions.</p> |
| <p>The following program uses <var class="LITERAL">mvhline()</var> |
| and <var class="LITERAL">mvvline()</var> to achieve similar effect. |
| These two functions are simple. They create a horizontal or |
| vertical line of the specified length at the specified |
| position.</p> |
| <div class="EXAMPLE"><a name="BOTBO" id="BOTBO"></a> |
| <p><b>Example 8. More border functions</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> |
| |
| typedef struct _win_border_struct { |
| chtype ls, rs, ts, bs, |
| tl, tr, bl, br; |
| }WIN_BORDER; |
| |
| typedef struct _WIN_struct { |
| |
| int startx, starty; |
| int height, width; |
| WIN_BORDER border; |
| }WIN; |
| |
| void init_win_params(WIN *p_win); |
| void print_win_params(WIN *p_win); |
| void create_box(WIN *win, bool flag); |
| |
| int main(int argc, char *argv[]) |
| { WIN win; |
| int ch; |
| |
| initscr(); /* Start curses mode */ |
| start_color(); /* Start the color functionality */ |
| cbreak(); /* Line buffering disabled, Pass on |
| * everty thing to me */ |
| keypad(stdscr, TRUE); /* I need that nifty F1 */ |
| noecho(); |
| init_pair(1, COLOR_CYAN, COLOR_BLACK); |
| |
| /* Initialize the window parameters */ |
| init_win_params(&win); |
| print_win_params(&win); |
| |
| attron(COLOR_PAIR(1)); |
| printw("Press F1 to exit"); |
| refresh(); |
| attroff(COLOR_PAIR(1)); |
| |
| create_box(&win, TRUE); |
| while((ch = getch()) != KEY_F(1)) |
| { switch(ch) |
| { case KEY_LEFT: |
| create_box(&win, FALSE); |
| --win.startx; |
| create_box(&win, TRUE); |
| break; |
| case KEY_RIGHT: |
| create_box(&win, FALSE); |
| ++win.startx; |
| create_box(&win, TRUE); |
| break; |
| case KEY_UP: |
| create_box(&win, FALSE); |
| --win.starty; |
| create_box(&win, TRUE); |
| break; |
| case KEY_DOWN: |
| create_box(&win, FALSE); |
| ++win.starty; |
| create_box(&win, TRUE); |
| break; |
| } |
| } |
| endwin(); /* End curses mode */ |
| return 0; |
| } |
| void init_win_params(WIN *p_win) |
| { |
| p_win->height = 3; |
| p_win->width = 10; |
| p_win->starty = (LINES - p_win->height)/2; |
| p_win->startx = (COLS - p_win->width)/2; |
| |
| p_win->border.ls = '|'; |
| p_win->border.rs = '|'; |
| p_win->border.ts = '-'; |
| p_win->border.bs = '-'; |
| p_win->border.tl = '+'; |
| p_win->border.tr = '+'; |
| p_win->border.bl = '+'; |
| p_win->border.br = '+'; |
| |
| } |
| void print_win_params(WIN *p_win) |
| { |
| #ifdef _DEBUG |
| mvprintw(25, 0, "%d %d %d %d", p_win->startx, p_win->starty, |
| p_win->width, p_win->height); |
| refresh(); |
| #endif |
| } |
| void create_box(WIN *p_win, bool flag) |
| { int i, j; |
| int x, y, w, h; |
| |
| x = p_win->startx; |
| y = p_win->starty; |
| w = p_win->width; |
| h = p_win->height; |
| |
| if(flag == TRUE) |
| { mvaddch(y, x, p_win->border.tl); |
| mvaddch(y, x + w, p_win->border.tr); |
| mvaddch(y + h, x, p_win->border.bl); |
| mvaddch(y + h, x + w, p_win->border.br); |
| mvhline(y, x + 1, p_win->border.ts, w - 1); |
| mvhline(y + h, x + 1, p_win->border.bs, w - 1); |
| mvvline(y + 1, x, p_win->border.ls, h - 1); |
| mvvline(y + 1, x + w, p_win->border.rs, h - 1); |
| |
| } |
| else |
| for(j = y; j <= y + h; ++j) |
| for(i = x; i <= x + w; ++i) |
| mvaddch(j, i, ' '); |
| |
| refresh(); |
| |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="COLOR" id="COLOR">10. Colors</a></h2> |
| <div class="SECT2"> |
| <h3 class="SECT2"><a name="COLORBASICS" id="COLORBASICS">10.1. The |
| basics</a></h3> |
| <p>Life seems dull with no colors. Curses has a nice mechanism to |
| handle colors. Let's get into the thick of the things with a small |
| program.</p> |
| <div class="EXAMPLE"><a name="BSICO" id="BSICO"></a> |
| <p><b>Example 9. A Simple Color example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> |
| |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string); |
| int main(int argc, char *argv[]) |
| { initscr(); /* Start curses mode */ |
| if(has_colors() == FALSE) |
| { endwin(); |
| printf("Your terminal does not support color\n"); |
| exit(1); |
| } |
| start_color(); /* Start color */ |
| init_pair(1, COLOR_RED, COLOR_BLACK); |
| |
| attron(COLOR_PAIR(1)); |
| print_in_middle(stdscr, LINES / 2, 0, 0, "Viola !!! In color ..."); |
| attroff(COLOR_PAIR(1)); |
| getch(); |
| endwin(); |
| } |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string) |
| { int length, x, y; |
| float temp; |
| |
| if(win == NULL) |
| win = stdscr; |
| getyx(win, y, x); |
| if(startx != 0) |
| x = startx; |
| if(starty != 0) |
| y = starty; |
| if(width == 0) |
| width = 80; |
| |
| length = strlen(string); |
| temp = (width - length)/ 2; |
| x = startx + (int)temp; |
| mvwprintw(win, y, x, "%s", string); |
| refresh(); |
| } |
| </span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>As you can see, to start using color, you should first call the |
| function <var class="LITERAL">start_color()</var>. After that, you |
| can use color capabilities of your terminals using various |
| functions. To find out whether a terminal has color capabilities or |
| not, you can use <var class="LITERAL">has_colors()</var> function, |
| which returns FALSE if the terminal does not support color.</p> |
| <p>Curses initializes all the colors supported by terminal when |
| start_color() is called. These can be accessed by the define |
| constants like <var class="LITERAL">COLOR_BLACK</var> etc. Now to |
| actually start using colors, you have to define pairs. Colors are |
| always used in pairs. That means you have to use the function |
| <var class="LITERAL">init_pair()</var> to define the foreground and |
| background for the pair number you give. After that that pair |
| number can be used as a normal attribute with <var class= |
| "LITERAL">COLOR_PAIR()</var>function. This may seem to be |
| cumbersome at first. But this elegant solution allows us to manage |
| color pairs very easily. To appreciate it, you have to look into |
| the the source code of "dialog", a utility for displaying dialog |
| boxes from shell scripts. The developers have defined foreground |
| and background combinations for all the colors they might need and |
| initialized at the beginning. This makes it very easy to set |
| attributes just by accessing a pair which we already have defined |
| as a constant.</p> |
| <p>The following colors are defined in <var class= |
| "LITERAL">curses.h</var>. You can use these as parameters for |
| various color functions.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> COLOR_BLACK 0 |
| COLOR_RED 1 |
| COLOR_GREEN 2 |
| COLOR_YELLOW 3 |
| COLOR_BLUE 4 |
| COLOR_MAGENTA 5 |
| COLOR_CYAN 6 |
| COLOR_WHITE 7</font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="CHANGECOLORDEFS" id= |
| "CHANGECOLORDEFS">10.2. Changing Color Definitions</a></h3> |
| <p>The function <var class="LITERAL">init_color()</var>can be used |
| to change the rgb values for the colors defined by curses |
| initially. Say you wanted to lighten the intensity of red color by |
| a minuscule. Then you can use this function as</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> init_color(COLOR_RED, 700, 0, 0); |
| /* param 1 : color name |
| * param 2, 3, 4 : rgb content min = 0, max = 1000 */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>If your terminal cannot change the color definitions, the |
| function returns ERR. The function <var class= |
| "LITERAL">can_change_color()</var> can be used to find out whether |
| the terminal has the capability of changing color content or not. |
| The rgb content is scaled from 0 to 1000. Initially RED color is |
| defined with content 1000(r), 0(g), 0(b).</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="COLORCONTENT" id="COLORCONTENT">10.3. |
| Color Content</a></h3> |
| <p>The functions <var class="LITERAL">color_content()</var> and |
| <var class="LITERAL">pair_content()</var> can be used to find the |
| color content and foreground, background combination for the |
| pair.</p> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="KEYS" id="KEYS">11. Interfacing with the |
| key board</a></h2> |
| <div class="SECT2"> |
| <h3 class="SECT2"><a name="KEYSBASICS" id="KEYSBASICS">11.1. The |
| Basics</a></h3> |
| <p>No GUI is complete without a strong user interface and to |
| interact with the user, a curses program should be sensitive to key |
| presses or the mouse actions done by the user. Let's deal with the |
| keys first.</p> |
| <p>As you have seen in almost all of the above examples, it's very |
| easy to get key input from the user. A simple way of getting key |
| presses is to use <var class="LITERAL">getch()</var> function. The |
| cbreak mode should be enabled to read keys when you are interested |
| in reading individual key hits rather than complete lines of text |
| (which usually end with a carriage return). keypad should be |
| enabled to get the Functions keys, arrow keys etc. See the |
| initialization section for details.</p> |
| <p><var class="LITERAL">getch()</var> returns an integer |
| corresponding to the key pressed. If it is a normal character, the |
| integer value will be equivalent to the character. Otherwise it |
| returns a number which can be matched with the constants defined in |
| <var class="LITERAL">curses.h</var>. For example if the user |
| presses F1, the integer returned is 265. This can be checked using |
| the macro KEY_F() defined in curses.h. This makes reading keys |
| portable and easy to manage.</p> |
| <p>For example, if you call getch() like this</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> int ch; |
| |
| ch = getch();</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>getch() will wait for the user to press a key, (unless you |
| specified a timeout) and when user presses a key, the corresponding |
| integer is returned. Then you can check the value returned with the |
| constants defined in curses.h to match against the keys you |
| want.</p> |
| <p>The following code piece will do that job.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> if(ch == KEY_LEFT) |
| printw("Left arrow is pressed\n");</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>Let's write a small program which creates a menu which can be |
| navigated by up and down arrows.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="SIMPLEKEYEX" id="SIMPLEKEYEX">11.2. A |
| Simple Key Usage example</a></h3> |
| <div class="EXAMPLE"><a name="BSIKE" id="BSIKE"></a> |
| <p><b>Example 10. A Simple Key Usage example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <stdio.h> |
| #include <ncurses.h> |
| |
| #define WIDTH 30 |
| #define HEIGHT 10 |
| |
| int startx = 0; |
| int starty = 0; |
| |
| char *choices[] = { |
| "Choice 1", |
| "Choice 2", |
| "Choice 3", |
| "Choice 4", |
| "Exit", |
| }; |
| int n_choices = sizeof(choices) / sizeof(char *); |
| void print_menu(WINDOW *menu_win, int highlight); |
| |
| int main() |
| { WINDOW *menu_win; |
| int highlight = 1; |
| int choice = 0; |
| int c; |
| |
| initscr(); |
| clear(); |
| noecho(); |
| cbreak(); /* Line buffering disabled. pass on everything */ |
| startx = (80 - WIDTH) / 2; |
| starty = (24 - HEIGHT) / 2; |
| |
| menu_win = newwin(HEIGHT, WIDTH, starty, startx); |
| keypad(menu_win, TRUE); |
| mvprintw(0, 0, "Use arrow keys to go up and down, Press enter to select a choice"); |
| refresh(); |
| print_menu(menu_win, highlight); |
| while(1) |
| { c = wgetch(menu_win); |
| switch(c) |
| { case KEY_UP: |
| if(highlight == 1) |
| highlight = n_choices; |
| else |
| --highlight; |
| break; |
| case KEY_DOWN: |
| if(highlight == n_choices) |
| highlight = 1; |
| else |
| ++highlight; |
| break; |
| case 10: |
| choice = highlight; |
| break; |
| default: |
| mvprintw(24, 0, "Charcter pressed is = %3d Hopefully it can be printed as '%c'", c, c); |
| refresh(); |
| break; |
| } |
| print_menu(menu_win, highlight); |
| if(choice != 0) /* User did a choice come out of the infinite loop */ |
| break; |
| } |
| mvprintw(23, 0, "You chose choice %d with choice string %s\n", choice, choices[choice - 1]); |
| clrtoeol(); |
| refresh(); |
| endwin(); |
| return 0; |
| } |
| |
| |
| void print_menu(WINDOW *menu_win, int highlight) |
| { |
| int x, y, i; |
| |
| x = 2; |
| y = 2; |
| box(menu_win, 0, 0); |
| for(i = 0; i < n_choices; ++i) |
| { if(highlight == i + 1) /* High light the present choice */ |
| { wattron(menu_win, A_REVERSE); |
| mvwprintw(menu_win, y, x, "%s", choices[i]); |
| wattroff(menu_win, A_REVERSE); |
| } |
| else |
| mvwprintw(menu_win, y, x, "%s", choices[i]); |
| ++y; |
| } |
| wrefresh(menu_win); |
| } |
| </span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="MOUSE" id="MOUSE">12. Interfacing with |
| the mouse</a></h2> |
| <p>Now that you have seen how to get keys, lets do the same thing |
| from mouse. Usually each UI allows the user to interact with both |
| keyboard and mouse.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MOUSEBASICS" id="MOUSEBASICS">12.1. The |
| Basics</a></h3> |
| <p>Before you do any thing else, the events you want to receive |
| have to be enabled with <var class="LITERAL">mousemask()</var>.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"> mousemask( mmask_t newmask, /* The events you want to listen to */ |
| mmask_t *oldmask) /* The old events mask */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The first parameter to above function is a bit mask of events |
| you would like to listen. By default, all the events are turned |
| off. The bit mask <var class="LITERAL">ALL_MOUSE_EVENTS</var> can |
| be used to get all the events.</p> |
| <p>The following are all the event masks:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> Name Description |
| --------------------------------------------------------------------- |
| BUTTON1_PRESSED mouse button 1 down |
| BUTTON1_RELEASED mouse button 1 up |
| BUTTON1_CLICKED mouse button 1 clicked |
| BUTTON1_DOUBLE_CLICKED mouse button 1 double clicked |
| BUTTON1_TRIPLE_CLICKED mouse button 1 triple clicked |
| BUTTON2_PRESSED mouse button 2 down |
| BUTTON2_RELEASED mouse button 2 up |
| BUTTON2_CLICKED mouse button 2 clicked |
| BUTTON2_DOUBLE_CLICKED mouse button 2 double clicked |
| BUTTON2_TRIPLE_CLICKED mouse button 2 triple clicked |
| BUTTON3_PRESSED mouse button 3 down |
| BUTTON3_RELEASED mouse button 3 up |
| BUTTON3_CLICKED mouse button 3 clicked |
| BUTTON3_DOUBLE_CLICKED mouse button 3 double clicked |
| BUTTON3_TRIPLE_CLICKED mouse button 3 triple clicked |
| BUTTON4_PRESSED mouse button 4 down |
| BUTTON4_RELEASED mouse button 4 up |
| BUTTON4_CLICKED mouse button 4 clicked |
| BUTTON4_DOUBLE_CLICKED mouse button 4 double clicked |
| BUTTON4_TRIPLE_CLICKED mouse button 4 triple clicked |
| BUTTON_SHIFT shift was down during button state change |
| BUTTON_CTRL control was down during button state change |
| BUTTON_ALT alt was down during button state change |
| ALL_MOUSE_EVENTS report all button state changes |
| REPORT_MOUSE_POSITION report mouse movement</font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="GETTINGEVENTS" id="GETTINGEVENTS">12.2. |
| Getting the events</a></h3> |
| <p>Once a class of mouse events have been enabled, getch() class of |
| functions return KEY_MOUSE every time some mouse event happens. |
| Then the mouse event can be retrieved with <var class= |
| "LITERAL">getmouse()</var>.</p> |
| <p>The code approximately looks like this:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> MEVENT event; |
| |
| ch = getch(); |
| if(ch == KEY_MOUSE) |
| if(getmouse(&event) == OK) |
| . /* Do some thing with the event */ |
| . |
| .</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>getmouse() returns the event into the pointer given to it. It's |
| a structure which contains</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> typedef struct |
| { |
| short id; /* ID to distinguish multiple devices */ |
| int x, y, z; /* event coordinates */ |
| mmask_t bstate; /* button state bits */ |
| } </font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The <var class="LITERAL">bstate</var> is the main variable we |
| are interested in. It tells the button state of the mouse.</p> |
| <p>Then with a code snippet like the following, we can find out |
| what happened.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> if(event.bstate & BUTTON1_PRESSED) |
| printw("Left Button Pressed");</font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MOUSETOGETHER" id="MOUSETOGETHER">12.3. |
| Putting it all Together</a></h3> |
| <p>That's pretty much interfacing with mouse. Let's create the same |
| menu and enable mouse interaction. To make things simpler, key |
| handling is removed.</p> |
| <div class="EXAMPLE"><a name="BMOME" id="BMOME"></a> |
| <p><b>Example 11. Access the menu with mouse !!!</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> |
| |
| #define WIDTH 30 |
| #define HEIGHT 10 |
| |
| int startx = 0; |
| int starty = 0; |
| |
| char *choices[] = { "Choice 1", |
| "Choice 2", |
| "Choice 3", |
| "Choice 4", |
| "Exit", |
| }; |
| |
| int n_choices = sizeof(choices) / sizeof(char *); |
| |
| void print_menu(WINDOW *menu_win, int highlight); |
| void report_choice(int mouse_x, int mouse_y, int *p_choice); |
| |
| int main() |
| { int c, choice = 0; |
| WINDOW *menu_win; |
| MEVENT event; |
| |
| /* Initialize curses */ |
| initscr(); |
| clear(); |
| noecho(); |
| cbreak(); //Line buffering disabled. pass on everything |
| |
| /* Try to put the window in the middle of screen */ |
| startx = (80 - WIDTH) / 2; |
| starty = (24 - HEIGHT) / 2; |
| |
| attron(A_REVERSE); |
| mvprintw(23, 1, "Click on Exit to quit (Works best in a virtual console)"); |
| refresh(); |
| attroff(A_REVERSE); |
| |
| /* Print the menu for the first time */ |
| menu_win = newwin(HEIGHT, WIDTH, starty, startx); |
| print_menu(menu_win, 1); |
| /* Get all the mouse events */ |
| mousemask(ALL_MOUSE_EVENTS, NULL); |
| |
| while(1) |
| { c = wgetch(menu_win); |
| switch(c) |
| { case KEY_MOUSE: |
| if(getmouse(&event) == OK) |
| { /* When the user clicks left mouse button */ |
| if(event.bstate & BUTTON1_PRESSED) |
| { report_choice(event.x + 1, event.y + 1, &choice); |
| if(choice == -1) //Exit chosen |
| goto end; |
| mvprintw(22, 1, "Choice made is : %d String Chosen is \"%10s\"", choice, choices[choice - 1]); |
| refresh(); |
| } |
| } |
| print_menu(menu_win, choice); |
| break; |
| } |
| } |
| end: |
| endwin(); |
| return 0; |
| } |
| |
| |
| void print_menu(WINDOW *menu_win, int highlight) |
| { |
| int x, y, i; |
| |
| x = 2; |
| y = 2; |
| box(menu_win, 0, 0); |
| for(i = 0; i < n_choices; ++i) |
| { if(highlight == i + 1) |
| { wattron(menu_win, A_REVERSE); |
| mvwprintw(menu_win, y, x, "%s", choices[i]); |
| wattroff(menu_win, A_REVERSE); |
| } |
| else |
| mvwprintw(menu_win, y, x, "%s", choices[i]); |
| ++y; |
| } |
| wrefresh(menu_win); |
| } |
| |
| /* Report the choice according to mouse position */ |
| void report_choice(int mouse_x, int mouse_y, int *p_choice) |
| { int i,j, choice; |
| |
| i = startx + 2; |
| j = starty + 3; |
| |
| for(choice = 0; choice < n_choices; ++choice) |
| if(mouse_y == j + choice && mouse_x >= i && mouse_x <= i + strlen(choices[choice])) |
| { if(choice == n_choices - 1) |
| *p_choice = -1; |
| else |
| *p_choice = choice + 1; |
| break; |
| } |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MISCMOUSEFUNCS" id= |
| "MISCMOUSEFUNCS">12.4. Miscellaneous Functions</a></h3> |
| <p>The functions mouse_trafo() and wmouse_trafo() can be used to |
| convert to mouse co-ordinates to screen relative co-ordinates. See |
| curs_mouse(3X) man page for details.</p> |
| <p>The mouseinterval function sets the maximum time (in thousands |
| of a second) that can elapse between press and release events in |
| order for them to be recognized as a click. This function returns |
| the previous interval value. The default is one fifth of a |
| second.</p> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="SCREEN" id="SCREEN">13. Screen |
| Manipulation</a></h2> |
| <p>In this section, we will look into some functions, which allow |
| us to manage the screen efficiently and to write some fancy |
| programs. This is especially important in writing games.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="GETYX" id="GETYX">13.1. getyx() |
| functions</a></h3> |
| <p>The function <var class="LITERAL">getyx()</var> can be used to |
| find out the present cursor co-ordinates. It will fill the values |
| of x and y co-ordinates in the arguments given to it. Since getyx() |
| is a macro you don't have to pass the address of the variables. It |
| can be called as</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> getyx(win, y, x); |
| /* win: window pointer |
| * y, x: y, x co-ordinates will be put into this variables |
| */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The function getparyx() gets the beginning co-ordinates of the |
| sub window relative to the main window. This is some times useful |
| to update a sub window. When designing fancy stuff like writing |
| multiple menus, it becomes difficult to store the menu positions, |
| their first option co-ordinates etc. A simple solution to this |
| problem, is to create menus in sub windows and later find the |
| starting co-ordinates of the menus by using getparyx().</p> |
| <p>The functions getbegyx() and getmaxyx() store current window's |
| beginning and maximum co-ordinates. These functions are useful in |
| the same way as above in managing the windows and sub windows |
| effectively.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="SCREENDUMP" id="SCREENDUMP">13.2. Screen |
| Dumping</a></h3> |
| <p>While writing games, some times it becomes necessary to store |
| the state of the screen and restore it back to the same state. The |
| function scr_dump() can be used to dump the screen contents to a |
| file given as an argument. Later it can be restored by scr_restore |
| function. These two simple functions can be used effectively to |
| maintain a fast moving game with changing scenarios.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="WINDOWDUMP" id="WINDOWDUMP">13.3. Window |
| Dumping</a></h3> |
| <p>To store and restore windows, the functions <var class= |
| "LITERAL">putwin()</var> and <var class="LITERAL">getwin()</var> |
| can be used. <var class="LITERAL">putwin()</var> puts the present |
| window state into a file, which can be later restored by |
| <var class="LITERAL">getwin()</var>.</p> |
| <p>The function <var class="LITERAL">copywin()</var> can be used to |
| copy a window completely onto another window. It takes the source |
| and destination windows as parameters and according to the |
| rectangle specified, it copies the rectangular region from source |
| to destination window. It's last parameter specifies whether to |
| overwrite or just overlay the contents on to the destination |
| window. If this argument is true, then the copying is |
| non-destructive.</p> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="MISC" id="MISC">14. Miscellaneous |
| features</a></h2> |
| <p>Now you know enough features to write a good curses program, |
| with all bells and whistles. There are some miscellaneous functions |
| which are useful in various cases. Let's go headlong into some of |
| those.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="CURSSET" id="CURSSET">14.1. |
| curs_set()</a></h3> |
| <p>This function can be used to make the cursor invisible. The |
| parameter to this function should be</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> 0 : invisible or |
| 1 : normal or |
| 2 : very visible.</font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="TEMPLEAVE" id="TEMPLEAVE">14.2. |
| Temporarily Leaving Curses mode</a></h3> |
| <p>Some times you may want to get back to cooked mode (normal line |
| buffering mode) temporarily. In such a case you will first need to |
| save the tty modes with a call to <var class= |
| "LITERAL">def_prog_mode()</var> and then call <var class= |
| "LITERAL">endwin()</var> to end the curses mode. This will leave |
| you in the original tty mode. To get back to curses once you are |
| done, call <var class="LITERAL">reset_prog_mode()</var> . This |
| function returns the tty to the state stored by <var class= |
| "LITERAL">def_prog_mode()</var>. Then do refresh(), and you are |
| back to the curses mode. Here is an example showing the sequence of |
| things to be done.</p> |
| <div class="EXAMPLE"><a name="BTELE" id="BTELE"></a> |
| <p><b>Example 12. Temporarily Leaving Curses Mode</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> |
| |
| int main() |
| { |
| initscr(); /* Start curses mode */ |
| printw("Hello World !!!\n"); /* Print Hello World */ |
| refresh(); /* Print it on to the real screen */ |
| def_prog_mode(); /* Save the tty modes */ |
| endwin(); /* End curses mode temporarily */ |
| system("/bin/sh"); /* Do whatever you like in cooked mode */ |
| reset_prog_mode(); /* Return to the previous tty mode*/ |
| /* stored by def_prog_mode() */ |
| refresh(); /* Do refresh() to restore the */ |
| /* Screen contents */ |
| printw("Another String\n"); /* Back to curses use the full */ |
| refresh(); /* capabilities of curses */ |
| endwin(); /* End curses mode */ |
| |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="ACSVARS" id="ACSVARS">14.3. ACS_ |
| variables</a></h3> |
| <p>If you have ever programmed in DOS, you know about those nifty |
| characters in extended character set. They are printable only on |
| some terminals. NCURSES functions like <var class= |
| "LITERAL">box()</var> use these characters. All these variables |
| start with ACS meaning alternative character set. You might have |
| noticed me using these characters in some of the programs above. |
| Here's an example showing all the characters.</p> |
| <div class="EXAMPLE"><a name="BACSVARS" id="BACSVARS"></a> |
| <p><b>Example 13. ACS Variables Example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <ncurses.h> |
| |
| int main() |
| { |
| initscr(); |
| |
| printw("Upper left corner "); addch(ACS_ULCORNER); printw("\n"); |
| printw("Lower left corner "); addch(ACS_LLCORNER); printw("\n"); |
| printw("Lower right corner "); addch(ACS_LRCORNER); printw("\n"); |
| printw("Tee pointing right "); addch(ACS_LTEE); printw("\n"); |
| printw("Tee pointing left "); addch(ACS_RTEE); printw("\n"); |
| printw("Tee pointing up "); addch(ACS_BTEE); printw("\n"); |
| printw("Tee pointing down "); addch(ACS_TTEE); printw("\n"); |
| printw("Horizontal line "); addch(ACS_HLINE); printw("\n"); |
| printw("Vertical line "); addch(ACS_VLINE); printw("\n"); |
| printw("Large Plus or cross over "); addch(ACS_PLUS); printw("\n"); |
| printw("Scan Line 1 "); addch(ACS_S1); printw("\n"); |
| printw("Scan Line 3 "); addch(ACS_S3); printw("\n"); |
| printw("Scan Line 7 "); addch(ACS_S7); printw("\n"); |
| printw("Scan Line 9 "); addch(ACS_S9); printw("\n"); |
| printw("Diamond "); addch(ACS_DIAMOND); printw("\n"); |
| printw("Checker board (stipple) "); addch(ACS_CKBOARD); printw("\n"); |
| printw("Degree Symbol "); addch(ACS_DEGREE); printw("\n"); |
| printw("Plus/Minus Symbol "); addch(ACS_PLMINUS); printw("\n"); |
| printw("Bullet "); addch(ACS_BULLET); printw("\n"); |
| printw("Arrow Pointing Left "); addch(ACS_LARROW); printw("\n"); |
| printw("Arrow Pointing Right "); addch(ACS_RARROW); printw("\n"); |
| printw("Arrow Pointing Down "); addch(ACS_DARROW); printw("\n"); |
| printw("Arrow Pointing Up "); addch(ACS_UARROW); printw("\n"); |
| printw("Board of squares "); addch(ACS_BOARD); printw("\n"); |
| printw("Lantern Symbol "); addch(ACS_LANTERN); printw("\n"); |
| printw("Solid Square Block "); addch(ACS_BLOCK); printw("\n"); |
| printw("Less/Equal sign "); addch(ACS_LEQUAL); printw("\n"); |
| printw("Greater/Equal sign "); addch(ACS_GEQUAL); printw("\n"); |
| printw("Pi "); addch(ACS_PI); printw("\n"); |
| printw("Not equal "); addch(ACS_NEQUAL); printw("\n"); |
| printw("UK pound sign "); addch(ACS_STERLING); printw("\n"); |
| |
| refresh(); |
| getch(); |
| endwin(); |
| |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="OTHERLIB" id="OTHERLIB">15. Other |
| libraries</a></h2> |
| <p>Apart from the curses library, there are few text mode |
| libraries, which provide more functionality and a lot of features. |
| The following sections explain three standard libraries which are |
| usually distributed along with curses.</p> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="PANELS" id="PANELS">16. Panel |
| Library</a></h2> |
| <p>Now that you are proficient in curses, you wanted to do some |
| thing big. You created a lot of overlapping windows to give a |
| professional windows-type look. Unfortunately, it soon becomes |
| difficult to manage these. The multiple refreshes, updates plunge |
| you into a nightmare. The overlapping windows create blotches, |
| whenever you forget to refresh the windows in the proper order.</p> |
| <p>Don't despair. There's an elegant solution provided in panels |
| library. In the words of developers of ncurses</p> |
| <p><em>When your interface design is such that windows may dive |
| deeper into the visibility stack or pop to the top at runtime, the |
| resulting book-keeping can be tedious and difficult to get right. |
| Hence the panels library.</em></p> |
| <p>If you have lot of overlapping windows, then panels library is |
| the way to go. It obviates the need of doing series of |
| wnoutrefresh(), doupdate() and relieves the burden of doing it |
| correctly(bottom up). The library maintains information about the |
| order of windows, their overlapping and update the screen properly. |
| So why wait? Let's take a close peek into panels.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="PANELBASICS" id="PANELBASICS">16.1. The |
| Basics</a></h3> |
| <p>Panel object is a window that is implicitly treated as part of a |
| deck including all other panel objects. The deck is treated as a |
| stack with the top panel being completely visible and the other |
| panels may or may not be obscured according to their positions. So |
| the basic idea is to create a stack of overlapping panels and use |
| panels library to display them correctly. There is a function |
| similar to refresh() which, when called , displays panels in the |
| correct order. Functions are provided to hide or show panels, move |
| panels, change its size etc.. The overlapping problem is managed by |
| the panels library during all the calls to these functions.</p> |
| <p>The general flow of a panel program goes like this:</p> |
| <ol type="1"> |
| <li> |
| <p>Create the windows (with newwin()) to be attached to the |
| panels.</p> |
| </li> |
| <li> |
| <p>Create panels with the chosen visibility order. Stack them up |
| according to the desired visibility. The function new_panel() is |
| used to created panels.</p> |
| </li> |
| <li> |
| <p>Call update_panels() to write the panels to the virtual screen |
| in correct visibility order. Do a doupdate() to show it on the |
| screen.</p> |
| </li> |
| <li> |
| <p>Mainpulate the panels with show_panel(), hide_panel(), |
| move_panel() etc. Make use of helper functions like panel_hidden() |
| and panel_window(). Make use of user pointer to store custom data |
| for a panel. Use the functions set_panel_userptr() and |
| panel_userptr() to set and get the user pointer for a panel.</p> |
| </li> |
| <li> |
| <p>When you are done with the panel use del_panel() to delete the |
| panel.</p> |
| </li> |
| </ol> |
| <p>Let's make the concepts clear, with some programs. The following |
| is a simple program which creates 3 overlapping panels and shows |
| them on the screen.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="COMPILEPANELS" id="COMPILEPANELS">16.2. |
| Compiling With the Panels Library</a></h3> |
| <p>To use panels library functions, you have to include panel.h and |
| to link the program with panels library the flag -lpanel should be |
| added along with -lncurses in that order.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> #include <panel.h> |
| . |
| . |
| . |
| |
| compile and link: gcc <program file> -lpanel -lncurses</font> |
| </pre></td> |
| </tr> |
| </table> |
| <div class="EXAMPLE"><a name="PPASI" id="PPASI"></a> |
| <p><b>Example 14. Panel basics</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <panel.h> |
| |
| int main() |
| { WINDOW *my_wins[3]; |
| PANEL *my_panels[3]; |
| int lines = 10, cols = 40, y = 2, x = 4, i; |
| |
| initscr(); |
| cbreak(); |
| noecho(); |
| |
| /* Create windows for the panels */ |
| my_wins[0] = newwin(lines, cols, y, x); |
| my_wins[1] = newwin(lines, cols, y + 1, x + 5); |
| my_wins[2] = newwin(lines, cols, y + 2, x + 10); |
| |
| /* |
| * Create borders around the windows so that you can see the effect |
| * of panels |
| */ |
| for(i = 0; i < 3; ++i) |
| box(my_wins[i], 0, 0); |
| |
| /* Attach a panel to each window */ /* Order is bottom up */ |
| my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ |
| my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ |
| my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ |
| |
| /* Update the stacking order. 2nd panel will be on top */ |
| update_panels(); |
| |
| /* Show it on the screen */ |
| doupdate(); |
| |
| getch(); |
| endwin(); |
| } |
| </span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>As you can see, above program follows a simple flow as |
| explained. The windows are created with newwin() and then they are |
| attached to panels with new_panel(). As we attach one panel after |
| another, the stack of panels gets updated. To put them on screen |
| update_panels() and doupdate() are called.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="PANELBROWSING" id="PANELBROWSING">16.3. |
| Panel Window Browsing</a></h3> |
| <p>A slightly complicated example is given below. This program |
| creates 3 windows which can be cycled through using tab. Have a |
| look at the code.</p> |
| <div class="EXAMPLE"><a name="PPABR" id="PPABR"></a> |
| <p><b>Example 15. Panel Window Browsing Example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <panel.h> |
| |
| #define NLINES 10 |
| #define NCOLS 40 |
| |
| void init_wins(WINDOW **wins, int n); |
| void win_show(WINDOW *win, char *label, int label_color); |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); |
| |
| int main() |
| { WINDOW *my_wins[3]; |
| PANEL *my_panels[3]; |
| PANEL *top; |
| int ch; |
| |
| /* Initialize curses */ |
| initscr(); |
| start_color(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| |
| /* Initialize all the colors */ |
| init_pair(1, COLOR_RED, COLOR_BLACK); |
| init_pair(2, COLOR_GREEN, COLOR_BLACK); |
| init_pair(3, COLOR_BLUE, COLOR_BLACK); |
| init_pair(4, COLOR_CYAN, COLOR_BLACK); |
| |
| init_wins(my_wins, 3); |
| |
| /* Attach a panel to each window */ /* Order is bottom up */ |
| my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ |
| my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ |
| my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ |
| |
| /* Set up the user pointers to the next panel */ |
| set_panel_userptr(my_panels[0], my_panels[1]); |
| set_panel_userptr(my_panels[1], my_panels[2]); |
| set_panel_userptr(my_panels[2], my_panels[0]); |
| |
| /* Update the stacking order. 2nd panel will be on top */ |
| update_panels(); |
| |
| /* Show it on the screen */ |
| attron(COLOR_PAIR(4)); |
| mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)"); |
| attroff(COLOR_PAIR(4)); |
| doupdate(); |
| |
| top = my_panels[2]; |
| while((ch = getch()) != KEY_F(1)) |
| { switch(ch) |
| { case 9: |
| top = (PANEL *)panel_userptr(top); |
| top_panel(top); |
| break; |
| } |
| update_panels(); |
| doupdate(); |
| } |
| endwin(); |
| return 0; |
| } |
| |
| /* Put all the windows */ |
| void init_wins(WINDOW **wins, int n) |
| { int x, y, i; |
| char label[80]; |
| |
| y = 2; |
| x = 10; |
| for(i = 0; i < n; ++i) |
| { wins[i] = newwin(NLINES, NCOLS, y, x); |
| sprintf(label, "Window Number %d", i + 1); |
| win_show(wins[i], label, i + 1); |
| y += 3; |
| x += 7; |
| } |
| } |
| |
| /* Show the window with a border and a label */ |
| void win_show(WINDOW *win, char *label, int label_color) |
| { int startx, starty, height, width; |
| |
| getbegyx(win, starty, startx); |
| getmaxyx(win, height, width); |
| |
| box(win, 0, 0); |
| mvwaddch(win, 2, 0, ACS_LTEE); |
| mvwhline(win, 2, 1, ACS_HLINE, width - 2); |
| mvwaddch(win, 2, width - 1, ACS_RTEE); |
| |
| print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color)); |
| } |
| |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) |
| { int length, x, y; |
| float temp; |
| |
| if(win == NULL) |
| win = stdscr; |
| getyx(win, y, x); |
| if(startx != 0) |
| x = startx; |
| if(starty != 0) |
| y = starty; |
| if(width == 0) |
| width = 80; |
| |
| length = strlen(string); |
| temp = (width - length)/ 2; |
| x = startx + (int)temp; |
| wattron(win, color); |
| mvwprintw(win, y, x, "%s", string); |
| wattroff(win, color); |
| refresh(); |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="USERPTRUSING" id="USERPTRUSING">16.4. |
| Using User Pointers</a></h3> |
| <p>In the above example I used user pointers to find out the next |
| window in the cycle. We can attach custom information to the panel |
| by specifying a user pointer, which can point to any information |
| you want to store. In this case I stored the pointer to the next |
| panel in the cycle. User pointer for a panel can be set with the |
| function <var class="LITERAL">set_panel_userptr()</var>. It can be |
| accessed using the function <var class= |
| "LITERAL">panel_userptr()</var> which will return the user pointer |
| for the panel given as argument. After finding the next panel in |
| the cycle It's brought to the top by the function top_panel(). This |
| function brings the panel given as argument to the top of the panel |
| stack.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="PANELMOVERESIZE" id= |
| "PANELMOVERESIZE">16.5. Moving and Resizing Panels</a></h3> |
| <p>The function <var class="LITERAL">move_panel()</var> can be used |
| to move a panel to the desired location. It does not change the |
| position of the panel in the stack. Make sure that you use |
| move_panel() instead mvwin() on the window associated with the |
| panel.</p> |
| <p>Resizing a panel is slightly complex. There is no straight |
| forward function just to resize the window associated with a panel. |
| A solution to resize a panel is to create a new window with the |
| desired sizes, change the window associated with the panel using |
| replace_panel(). Don't forget to delete the old window. The window |
| associated with a panel can be found by using the function |
| panel_window().</p> |
| <p>The following program shows these concepts, in supposedly simple |
| program. You can cycle through the window with <TAB> as |
| usual. To resize or move the active panel press 'r' for resize 'm' |
| for moving. Then use arrow keys to resize or move it to the desired |
| way and press enter to end your resizing or moving. This example |
| makes use of user data to get the required data to do the |
| operations.</p> |
| <div class="EXAMPLE"><a name="PPARE" id="PPARE"></a> |
| <p><b>Example 16. Panel Moving and Resizing example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <panel.h> |
| |
| typedef struct _PANEL_DATA { |
| int x, y, w, h; |
| char label[80]; |
| int label_color; |
| PANEL *next; |
| }PANEL_DATA; |
| |
| #define NLINES 10 |
| #define NCOLS 40 |
| |
| void init_wins(WINDOW **wins, int n); |
| void win_show(WINDOW *win, char *label, int label_color); |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); |
| void set_user_ptrs(PANEL **panels, int n); |
| |
| int main() |
| { WINDOW *my_wins[3]; |
| PANEL *my_panels[3]; |
| PANEL_DATA *top; |
| PANEL *stack_top; |
| WINDOW *temp_win, *old_win; |
| int ch; |
| int newx, newy, neww, newh; |
| int size = FALSE, move = FALSE; |
| |
| /* Initialize curses */ |
| initscr(); |
| start_color(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| |
| /* Initialize all the colors */ |
| init_pair(1, COLOR_RED, COLOR_BLACK); |
| init_pair(2, COLOR_GREEN, COLOR_BLACK); |
| init_pair(3, COLOR_BLUE, COLOR_BLACK); |
| init_pair(4, COLOR_CYAN, COLOR_BLACK); |
| |
| init_wins(my_wins, 3); |
| |
| /* Attach a panel to each window */ /* Order is bottom up */ |
| my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ |
| my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ |
| my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ |
| |
| set_user_ptrs(my_panels, 3); |
| /* Update the stacking order. 2nd panel will be on top */ |
| update_panels(); |
| |
| /* Show it on the screen */ |
| attron(COLOR_PAIR(4)); |
| mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing"); |
| mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)"); |
| attroff(COLOR_PAIR(4)); |
| doupdate(); |
| |
| stack_top = my_panels[2]; |
| top = (PANEL_DATA *)panel_userptr(stack_top); |
| newx = top->x; |
| newy = top->y; |
| neww = top->w; |
| newh = top->h; |
| while((ch = getch()) != KEY_F(1)) |
| { switch(ch) |
| { case 9: /* Tab */ |
| top = (PANEL_DATA *)panel_userptr(stack_top); |
| top_panel(top->next); |
| stack_top = top->next; |
| top = (PANEL_DATA *)panel_userptr(stack_top); |
| newx = top->x; |
| newy = top->y; |
| neww = top->w; |
| newh = top->h; |
| break; |
| case 'r': /* Re-Size*/ |
| size = TRUE; |
| attron(COLOR_PAIR(4)); |
| mvprintw(LINES - 4, 0, "Entered Resizing :Use Arrow Keys to resize and press <ENTER> to end resizing"); |
| refresh(); |
| attroff(COLOR_PAIR(4)); |
| break; |
| case 'm': /* Move */ |
| attron(COLOR_PAIR(4)); |
| mvprintw(LINES - 4, 0, "Entered Moving: Use Arrow Keys to Move and press <ENTER> to end moving"); |
| refresh(); |
| attroff(COLOR_PAIR(4)); |
| move = TRUE; |
| break; |
| case KEY_LEFT: |
| if(size == TRUE) |
| { --newx; |
| ++neww; |
| } |
| if(move == TRUE) |
| --newx; |
| break; |
| case KEY_RIGHT: |
| if(size == TRUE) |
| { ++newx; |
| --neww; |
| } |
| if(move == TRUE) |
| ++newx; |
| break; |
| case KEY_UP: |
| if(size == TRUE) |
| { --newy; |
| ++newh; |
| } |
| if(move == TRUE) |
| --newy; |
| break; |
| case KEY_DOWN: |
| if(size == TRUE) |
| { ++newy; |
| --newh; |
| } |
| if(move == TRUE) |
| ++newy; |
| break; |
| case 10: /* Enter */ |
| move(LINES - 4, 0); |
| clrtoeol(); |
| refresh(); |
| if(size == TRUE) |
| { old_win = panel_window(stack_top); |
| temp_win = newwin(newh, neww, newy, newx); |
| replace_panel(stack_top, temp_win); |
| win_show(temp_win, top->label, top->label_color); |
| delwin(old_win); |
| size = FALSE; |
| } |
| if(move == TRUE) |
| { move_panel(stack_top, newy, newx); |
| move = FALSE; |
| } |
| break; |
| |
| } |
| attron(COLOR_PAIR(4)); |
| mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing"); |
| mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)"); |
| attroff(COLOR_PAIR(4)); |
| refresh(); |
| update_panels(); |
| doupdate(); |
| } |
| endwin(); |
| return 0; |
| } |
| |
| /* Put all the windows */ |
| void init_wins(WINDOW **wins, int n) |
| { int x, y, i; |
| char label[80]; |
| |
| y = 2; |
| x = 10; |
| for(i = 0; i < n; ++i) |
| { wins[i] = newwin(NLINES, NCOLS, y, x); |
| sprintf(label, "Window Number %d", i + 1); |
| win_show(wins[i], label, i + 1); |
| y += 3; |
| x += 7; |
| } |
| } |
| |
| /* Set the PANEL_DATA structures for individual panels */ |
| void set_user_ptrs(PANEL **panels, int n) |
| { PANEL_DATA *ptrs; |
| WINDOW *win; |
| int x, y, w, h, i; |
| char temp[80]; |
| |
| ptrs = (PANEL_DATA *)calloc(n, sizeof(PANEL_DATA)); |
| |
| for(i = 0;i < n; ++i) |
| { win = panel_window(panels[i]); |
| getbegyx(win, y, x); |
| getmaxyx(win, h, w); |
| ptrs[i].x = x; |
| ptrs[i].y = y; |
| ptrs[i].w = w; |
| ptrs[i].h = h; |
| sprintf(temp, "Window Number %d", i + 1); |
| strcpy(ptrs[i].label, temp); |
| ptrs[i].label_color = i + 1; |
| if(i + 1 == n) |
| ptrs[i].next = panels[0]; |
| else |
| ptrs[i].next = panels[i + 1]; |
| set_panel_userptr(panels[i], &ptrs[i]); |
| } |
| } |
| |
| /* Show the window with a border and a label */ |
| void win_show(WINDOW *win, char *label, int label_color) |
| { int startx, starty, height, width; |
| |
| getbegyx(win, starty, startx); |
| getmaxyx(win, height, width); |
| |
| box(win, 0, 0); |
| mvwaddch(win, 2, 0, ACS_LTEE); |
| mvwhline(win, 2, 1, ACS_HLINE, width - 2); |
| mvwaddch(win, 2, width - 1, ACS_RTEE); |
| |
| print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color)); |
| } |
| |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) |
| { int length, x, y; |
| float temp; |
| |
| if(win == NULL) |
| win = stdscr; |
| getyx(win, y, x); |
| if(startx != 0) |
| x = startx; |
| if(starty != 0) |
| y = starty; |
| if(width == 0) |
| width = 80; |
| |
| length = strlen(string); |
| temp = (width - length)/ 2; |
| x = startx + (int)temp; |
| wattron(win, color); |
| mvwprintw(win, y, x, "%s", string); |
| wattroff(win, color); |
| refresh(); |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>Concentrate on the main while loop. Once it finds out the type |
| of key pressed, it takes appropriate action. If 'r' is pressed |
| resizing mode is started. After this the new sizes are updated as |
| the user presses the arrow keys. When the user presses |
| <ENTER> present selection ends and panel is resized by using |
| the concept explained. While in resizing mode the program doesn't |
| show how the window is getting resized. It's left as an exercise to |
| the reader to print a dotted border while it gets resized to a new |
| position.</p> |
| <p>When the user presses 'm' the move mode starts. This is a bit |
| simpler than resizing. As the arrow keys are pressed the new |
| position is updated and pressing of <ENTER> causes the panel |
| to be moved by calling the function move_panel().</p> |
| <p>In this program the user data which is represented as |
| PANEL_DATA, plays very important role in finding the associated |
| information with a panel. As written in the comments, the |
| PANEL_DATA stores the panel sizes, label, label color and a pointer |
| to the next panel in the cycle.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="PANELSHOWHIDE" id="PANELSHOWHIDE">16.6. |
| Hiding and Showing Panels</a></h3> |
| <p>A Panel can be hidden by using the function hide_panel(). This |
| function merely removes it form the stack of panels, thus hiding it |
| on the screen once you do update_panels() and doupdate(). It |
| doesn't destroy the PANEL structure associated with the hidden |
| panel. It can be shown again by using the show_panel() |
| function.</p> |
| <p>The following program shows the hiding of panels. Press 'a' or |
| 'b' or 'c' to show or hide first, second and third windows |
| respectively. It uses a user data with a small variable hide, which |
| keeps track of whether the window is hidden or not. For some reason |
| the function <var class="LITERAL">panel_hidden()</var> which tells |
| whether a panel is hidden or not is not working. A bug report was |
| also presented by Michael Andres <a href= |
| "http://www.geocrawler.com/archives/3/344/1999/9/0/2643549/" |
| target="_top">here</a></p> |
| <div class="EXAMPLE"><a name="PPAHI" id="PPAHI"></a> |
| <p><b>Example 17. Panel Hiding and Showing example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <panel.h> |
| |
| typedef struct _PANEL_DATA { |
| int hide; /* TRUE if panel is hidden */ |
| }PANEL_DATA; |
| |
| #define NLINES 10 |
| #define NCOLS 40 |
| |
| void init_wins(WINDOW **wins, int n); |
| void win_show(WINDOW *win, char *label, int label_color); |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); |
| |
| int main() |
| { WINDOW *my_wins[3]; |
| PANEL *my_panels[3]; |
| PANEL_DATA panel_datas[3]; |
| PANEL_DATA *temp; |
| int ch; |
| |
| /* Initialize curses */ |
| initscr(); |
| start_color(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| |
| /* Initialize all the colors */ |
| init_pair(1, COLOR_RED, COLOR_BLACK); |
| init_pair(2, COLOR_GREEN, COLOR_BLACK); |
| init_pair(3, COLOR_BLUE, COLOR_BLACK); |
| init_pair(4, COLOR_CYAN, COLOR_BLACK); |
| |
| init_wins(my_wins, 3); |
| |
| /* Attach a panel to each window */ /* Order is bottom up */ |
| my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ |
| my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ |
| my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ |
| |
| /* Initialize panel datas saying that nothing is hidden */ |
| panel_datas[0].hide = FALSE; |
| panel_datas[1].hide = FALSE; |
| panel_datas[2].hide = FALSE; |
| |
| set_panel_userptr(my_panels[0], &panel_datas[0]); |
| set_panel_userptr(my_panels[1], &panel_datas[1]); |
| set_panel_userptr(my_panels[2], &panel_datas[2]); |
| |
| /* Update the stacking order. 2nd panel will be on top */ |
| update_panels(); |
| |
| /* Show it on the screen */ |
| attron(COLOR_PAIR(4)); |
| mvprintw(LINES - 3, 0, "Show or Hide a window with 'a'(first window) 'b'(Second Window) 'c'(Third Window)"); |
| mvprintw(LINES - 2, 0, "F1 to Exit"); |
| |
| attroff(COLOR_PAIR(4)); |
| doupdate(); |
| |
| while((ch = getch()) != KEY_F(1)) |
| { switch(ch) |
| { case 'a': |
| temp = (PANEL_DATA *)panel_userptr(my_panels[0]); |
| if(temp->hide == FALSE) |
| { hide_panel(my_panels[0]); |
| temp->hide = TRUE; |
| } |
| else |
| { show_panel(my_panels[0]); |
| temp->hide = FALSE; |
| } |
| break; |
| case 'b': |
| temp = (PANEL_DATA *)panel_userptr(my_panels[1]); |
| if(temp->hide == FALSE) |
| { hide_panel(my_panels[1]); |
| temp->hide = TRUE; |
| } |
| else |
| { show_panel(my_panels[1]); |
| temp->hide = FALSE; |
| } |
| break; |
| case 'c': |
| temp = (PANEL_DATA *)panel_userptr(my_panels[2]); |
| if(temp->hide == FALSE) |
| { hide_panel(my_panels[2]); |
| temp->hide = TRUE; |
| } |
| else |
| { show_panel(my_panels[2]); |
| temp->hide = FALSE; |
| } |
| break; |
| } |
| update_panels(); |
| doupdate(); |
| } |
| endwin(); |
| return 0; |
| } |
| |
| /* Put all the windows */ |
| void init_wins(WINDOW **wins, int n) |
| { int x, y, i; |
| char label[80]; |
| |
| y = 2; |
| x = 10; |
| for(i = 0; i < n; ++i) |
| { wins[i] = newwin(NLINES, NCOLS, y, x); |
| sprintf(label, "Window Number %d", i + 1); |
| win_show(wins[i], label, i + 1); |
| y += 3; |
| x += 7; |
| } |
| } |
| |
| /* Show the window with a border and a label */ |
| void win_show(WINDOW *win, char *label, int label_color) |
| { int startx, starty, height, width; |
| |
| getbegyx(win, starty, startx); |
| getmaxyx(win, height, width); |
| |
| box(win, 0, 0); |
| mvwaddch(win, 2, 0, ACS_LTEE); |
| mvwhline(win, 2, 1, ACS_HLINE, width - 2); |
| mvwaddch(win, 2, width - 1, ACS_RTEE); |
| |
| print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color)); |
| } |
| |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) |
| { int length, x, y; |
| float temp; |
| |
| if(win == NULL) |
| win = stdscr; |
| getyx(win, y, x); |
| if(startx != 0) |
| x = startx; |
| if(starty != 0) |
| y = starty; |
| if(width == 0) |
| width = 80; |
| |
| length = strlen(string); |
| temp = (width - length)/ 2; |
| x = startx + (int)temp; |
| wattron(win, color); |
| mvwprintw(win, y, x, "%s", string); |
| wattroff(win, color); |
| refresh(); |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="PANELABOVE" id="PANELABOVE">16.7. |
| panel_above() and panel_below() Functions</a></h3> |
| <p>The functions <var class="LITERAL">panel_above()</var> and |
| <var class="LITERAL">panel_below()</var> can be used to find out |
| the panel above and below a panel. If the argument to these |
| functions is NULL, then they return a pointer to bottom panel and |
| top panel respectively.</p> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="MENUS" id="MENUS">17. Menus |
| Library</a></h2> |
| <p>The menus library provides a nice extension to basic curses, |
| through which you can create menus. It provides a set of functions |
| to create menus. But they have to be customized to give a nicer |
| look, with colors etc. Let's get into the details.</p> |
| <p>A menu is a screen display that assists the user to choose some |
| subset of a given set of items. To put it simple, a menu is a |
| collection of items from which one or more items can be chosen. |
| Some readers might not be aware of multiple item selection |
| capability. Menu library provides functionality to write menus from |
| which the user can chose more than one item as the preferred |
| choice. This is dealt with in a later section. Now it is time for |
| some rudiments.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MENUBASICS" id="MENUBASICS">17.1. The |
| Basics</a></h3> |
| <p>To create menus, you first create items, and then post the menu |
| to the display. After that, all the processing of user responses is |
| done in an elegant function menu_driver() which is the work horse |
| of any menu program.</p> |
| <p>The general flow of control of a menu program looks like |
| this.</p> |
| <ol type="1"> |
| <li> |
| <p>Initialize curses</p> |
| </li> |
| <li> |
| <p>Create items using new_item(). You can specify a name and |
| description for the items.</p> |
| </li> |
| <li> |
| <p>Create the menu with new_menu() by specifying the items to be |
| attached with.</p> |
| </li> |
| <li> |
| <p>Post the menu with menu_post() and refresh the screen.</p> |
| </li> |
| <li> |
| <p>Process the user requests with a loop and do necessary updates |
| to menu with menu_driver.</p> |
| </li> |
| <li> |
| <p>Unpost the menu with menu_unpost()</p> |
| </li> |
| <li> |
| <p>Free the memory allocated to menu by free_menu()</p> |
| </li> |
| <li> |
| <p>Free the memory allocated to the items with free_item()</p> |
| </li> |
| <li> |
| <p>End curses</p> |
| </li> |
| </ol> |
| <p>Let's see a program which prints a simple menu and updates the |
| current selection with up, down arrows.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="COMPILEMENUS" id="COMPILEMENUS">17.2. |
| Compiling With the Menu Library</a></h3> |
| <p>To use menu library functions, you have to include menu.h and to |
| link the program with menu library the flag -lmenu should be added |
| along with -lncurses in that order.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> #include <menu.h> |
| . |
| . |
| . |
| |
| compile and link: gcc <program file> -lmenu -lncurses</font> |
| </pre></td> |
| </tr> |
| </table> |
| <div class="EXAMPLE"><a name="MMESI" id="MMESI"></a> |
| <p><b>Example 18. Menu Basics</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <curses.h> |
| #include <menu.h> |
| |
| #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) |
| #define CTRLD 4 |
| |
| char *choices[] = { |
| "Choice 1", |
| "Choice 2", |
| "Choice 3", |
| "Choice 4", |
| "Exit", |
| }; |
| |
| int main() |
| { ITEM **my_items; |
| int c; |
| MENU *my_menu; |
| int n_choices, i; |
| ITEM *cur_item; |
| |
| |
| initscr(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| |
| n_choices = ARRAY_SIZE(choices); |
| my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); |
| |
| for(i = 0; i < n_choices; ++i) |
| my_items[i] = new_item(choices[i], choices[i]); |
| my_items[n_choices] = (ITEM *)NULL; |
| |
| my_menu = new_menu((ITEM **)my_items); |
| mvprintw(LINES - 2, 0, "F1 to Exit"); |
| post_menu(my_menu); |
| refresh(); |
| |
| while((c = getch()) != KEY_F(1)) |
| { switch(c) |
| { case KEY_DOWN: |
| menu_driver(my_menu, REQ_DOWN_ITEM); |
| break; |
| case KEY_UP: |
| menu_driver(my_menu, REQ_UP_ITEM); |
| break; |
| } |
| } |
| |
| free_item(my_items[0]); |
| free_item(my_items[1]); |
| free_menu(my_menu); |
| endwin(); |
| } |
| </span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>This program demonstrates the basic concepts involved in |
| creating a menu using menus library. First we create the items |
| using new_item() and then attach them to the menu with new_menu() |
| function. After posting the menu and refreshing the screen, the |
| main processing loop starts. It reads user input and takes |
| corresponding action. The function menu_driver() is the main work |
| horse of the menu system. The second parameter to this function |
| tells what's to be done with the menu. According to the parameter, |
| menu_driver() does the corresponding task. The value can be either |
| a menu navigational request, an ascii character, or a KEY_MOUSE |
| special key associated with a mouse event.</p> |
| <p>The menu_driver accepts following navigational requests.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"> REQ_LEFT_ITEM Move left to an item. |
| REQ_RIGHT_ITEM Move right to an item. |
| REQ_UP_ITEM Move up to an item. |
| REQ_DOWN_ITEM Move down to an item. |
| REQ_SCR_ULINE Scroll up a line. |
| REQ_SCR_DLINE Scroll down a line. |
| REQ_SCR_DPAGE Scroll down a page. |
| REQ_SCR_UPAGE Scroll up a page. |
| REQ_FIRST_ITEM Move to the first item. |
| REQ_LAST_ITEM Move to the last item. |
| REQ_NEXT_ITEM Move to the next item. |
| REQ_PREV_ITEM Move to the previous item. |
| REQ_TOGGLE_ITEM Select/deselect an item. |
| REQ_CLEAR_PATTERN Clear the menu pattern buffer. |
| REQ_BACK_PATTERN Delete the previous character from the pattern buffer. |
| REQ_NEXT_MATCH Move to the next item matching the pattern match. |
| REQ_PREV_MATCH Move to the previous item matching the pattern match. </font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>Don't get overwhelmed by the number of options. We will see them |
| slowly one after another. The options of interest in this example |
| are REQ_UP_ITEM and REQ_DOWN_ITEM. These two options when passed to |
| menu_driver, menu driver updates the current item to one item up or |
| down respectively.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MENUDRIVER" id="MENUDRIVER">17.3. Menu |
| Driver: The work horse of the menu system</a></h3> |
| <p>As you have seen in the above example, menu_driver plays an |
| important role in updating the menu. It is very important to |
| understand various options it takes and what they do. As explained |
| above, the second parameter to menu_driver() can be either a |
| navigational request, a printable character or a KEY_MOUSE key. |
| Let's dissect the different navigational requests.</p> |
| <ul> |
| <li> |
| <p><em>REQ_LEFT_ITEM and REQ_RIGHT_ITEM</em></p> |
| <p>A Menu can be displayed with multiple columns for more than one |
| item. This can be done by using the <var class= |
| "LITERAL">menu_format()</var>function. When a multi columnar menu |
| is displayed these requests cause the menu driver to move the |
| current selection to left or right.</p> |
| </li> |
| <li> |
| <p><em>REQ_UP_ITEM and REQ_DOWN_ITEM</em></p> |
| <p>These two options you have seen in the above example. These |
| options when given, makes the menu_driver to move the current |
| selection to an item up or down.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_* options</em></p> |
| <p>The four options REQ_SCR_ULINE, REQ_SCR_DLINE, REQ_SCR_DPAGE, |
| REQ_SCR_UPAGE are related to scrolling. If all the items in the |
| menu cannot be displayed in the menu sub window, then the menu is |
| scrollable. These requests can be given to the menu_driver to do |
| the scrolling either one line up, down or one page down or up |
| respectively.</p> |
| </li> |
| <li> |
| <p><em>REQ_FIRST_ITEM, REQ_LAST_ITEM, REQ_NEXT_ITEM and |
| REQ_PREV_ITEM</em></p> |
| <p>These requests are self explanatory.</p> |
| </li> |
| <li> |
| <p><em>REQ_TOGGLE_ITEM</em></p> |
| <p>This request when given, toggles the present selection. This |
| option is to be used only in a multi valued menu. So to use this |
| request the option O_ONEVALUE must be off. This option can be made |
| off or on with set_menu_opts().</p> |
| </li> |
| <li> |
| <p><em>Pattern Requests</em></p> |
| <p>Every menu has an associated pattern buffer, which is used to |
| find the nearest match to the ascii characters entered by the user. |
| Whenever ascii characters are given to menu_driver, it puts in to |
| the pattern buffer. It also tries to find the nearest match to the |
| pattern in the items list and moves current selection to that item. |
| The request REQ_CLEAR_PATTERN clears the pattern buffer. The |
| request REQ_BACK_PATTERN deletes the previous character in the |
| pattern buffer. In case the pattern matches more than one item then |
| the matched items can be cycled through REQ_NEXT_MATCH and |
| REQ_PREV_MATCH which move the current selection to the next and |
| previous matches respectively.</p> |
| </li> |
| <li> |
| <p><em>Mouse Requests</em></p> |
| <p>In case of KEY_MOUSE requests, according to the mouse position |
| an action is taken accordingly. The action to be taken is explained |
| in the man page as,</p> |
| <table border="0" bgcolor="#E0E0E0" width="90%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"><em> If the second argument is the KEY_MOUSE special key, the |
| associated mouse event is translated into one of the above |
| pre-defined requests. Currently only clicks in the user |
| window (e.g. inside the menu display area or the decora­ |
| tion window) are handled. If you click above the display |
| region of the menu, a REQ_SCR_ULINE is generated, if you |
| doubleclick a REQ_SCR_UPAGE is generated and if you |
| tripleclick a REQ_FIRST_ITEM is generated. If you click |
| below the display region of the menu, a REQ_SCR_DLINE is |
| generated, if you doubleclick a REQ_SCR_DPAGE is generated |
| and if you tripleclick a REQ_LAST_ITEM is generated. If |
| you click at an item inside the display area of the menu, |
| the menu cursor is positioned to that item.</em></font> |
| </pre></td> |
| </tr> |
| </table> |
| </li> |
| </ul> |
| <p>Each of the above requests will be explained in the following |
| lines with several examples whenever appropriate.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MENUWINDOWS" id="MENUWINDOWS">17.4. Menu |
| Windows</a></h3> |
| <p>Every menu created is associated with a window and a sub window. |
| The menu window displays any title or border associated with the |
| menu. The menu sub window displays the menu items currently |
| available for selection. But we didn't specify any window or sub |
| window in the simple example. When a window is not specified, |
| stdscr is taken as the main window, and then menu system calculates |
| the sub window size required for the display of items. Then items |
| are displayed in the calculated sub window. So let's play with |
| these windows and display a menu with a border and a title.</p> |
| <div class="EXAMPLE"><a name="MMEWI" id="MMEWI"></a> |
| <p><b>Example 19. Menu Windows Usage example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <menu.h> |
| |
| #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) |
| #define CTRLD 4 |
| |
| char *choices[] = { |
| "Choice 1", |
| "Choice 2", |
| "Choice 3", |
| "Choice 4", |
| "Exit", |
| (char *)NULL, |
| }; |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); |
| |
| int main() |
| { ITEM **my_items; |
| int c; |
| MENU *my_menu; |
| WINDOW *my_menu_win; |
| int n_choices, i; |
| |
| /* Initialize curses */ |
| initscr(); |
| start_color(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| init_pair(1, COLOR_RED, COLOR_BLACK); |
| |
| /* Create items */ |
| n_choices = ARRAY_SIZE(choices); |
| my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *)); |
| for(i = 0; i < n_choices; ++i) |
| my_items[i] = new_item(choices[i], choices[i]); |
| |
| /* Crate menu */ |
| my_menu = new_menu((ITEM **)my_items); |
| |
| /* Create the window to be associated with the menu */ |
| my_menu_win = newwin(10, 40, 4, 4); |
| keypad(my_menu_win, TRUE); |
| |
| /* Set main window and sub window */ |
| set_menu_win(my_menu, my_menu_win); |
| set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1)); |
| |
| /* Set menu mark to the string " * " */ |
| set_menu_mark(my_menu, " * "); |
| |
| /* Print a border around the main window and print a title */ |
| box(my_menu_win, 0, 0); |
| print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1)); |
| mvwaddch(my_menu_win, 2, 0, ACS_LTEE); |
| mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38); |
| mvwaddch(my_menu_win, 2, 39, ACS_RTEE); |
| mvprintw(LINES - 2, 0, "F1 to exit"); |
| refresh(); |
| |
| /* Post the menu */ |
| post_menu(my_menu); |
| wrefresh(my_menu_win); |
| |
| while((c = wgetch(my_menu_win)) != KEY_F(1)) |
| { switch(c) |
| { case KEY_DOWN: |
| menu_driver(my_menu, REQ_DOWN_ITEM); |
| break; |
| case KEY_UP: |
| menu_driver(my_menu, REQ_UP_ITEM); |
| break; |
| } |
| wrefresh(my_menu_win); |
| } |
| |
| /* Unpost and free all the memory taken up */ |
| unpost_menu(my_menu); |
| free_menu(my_menu); |
| for(i = 0; i < n_choices; ++i) |
| free_item(my_items[i]); |
| endwin(); |
| } |
| |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) |
| { int length, x, y; |
| float temp; |
| |
| if(win == NULL) |
| win = stdscr; |
| getyx(win, y, x); |
| if(startx != 0) |
| x = startx; |
| if(starty != 0) |
| y = starty; |
| if(width == 0) |
| width = 80; |
| |
| length = strlen(string); |
| temp = (width - length)/ 2; |
| x = startx + (int)temp; |
| wattron(win, color); |
| mvwprintw(win, y, x, "%s", string); |
| wattroff(win, color); |
| refresh(); |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>This example creates a menu with a title, border, a fancy line |
| separating title and the items. As you can see, in order to attach |
| a window to a menu the function set_menu_win() has to be used. Then |
| we attach the sub window also. This displays the items in the sub |
| window. You can also set the mark string which gets displayed to |
| the left of the selected item with set_menu_mark().</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="SCROLLMENUS" id="SCROLLMENUS">17.5. |
| Scrolling Menus</a></h3> |
| <p>If the sub window given for a window is not big enough to show |
| all the items, then the menu will be scrollable. When you are on |
| the last item in the present list, if you send REQ_DOWN_ITEM, it |
| gets translated into REQ_SCR_DLINE and the menu scrolls by one |
| item. You can manually give REQ_SCR_ operations to do scrolling. |
| Let's see how it can be done.</p> |
| <div class="EXAMPLE"><a name="MMESC" id="MMESC"></a> |
| <p><b>Example 20. Scrolling Menus example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <curses.h> |
| #include <menu.h> |
| |
| #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) |
| #define CTRLD 4 |
| |
| char *choices[] = { |
| "Choice 1", |
| "Choice 2", |
| "Choice 3", |
| "Choice 4", |
| "Choice 5", |
| "Choice 6", |
| "Choice 7", |
| "Choice 8", |
| "Choice 9", |
| "Choice 10", |
| "Exit", |
| (char *)NULL, |
| }; |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); |
| |
| int main() |
| { ITEM **my_items; |
| int c; |
| MENU *my_menu; |
| WINDOW *my_menu_win; |
| int n_choices, i; |
| |
| /* Initialize curses */ |
| initscr(); |
| start_color(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| init_pair(1, COLOR_RED, COLOR_BLACK); |
| init_pair(2, COLOR_CYAN, COLOR_BLACK); |
| |
| /* Create items */ |
| n_choices = ARRAY_SIZE(choices); |
| my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *)); |
| for(i = 0; i < n_choices; ++i) |
| my_items[i] = new_item(choices[i], choices[i]); |
| |
| /* Crate menu */ |
| my_menu = new_menu((ITEM **)my_items); |
| |
| /* Create the window to be associated with the menu */ |
| my_menu_win = newwin(10, 40, 4, 4); |
| keypad(my_menu_win, TRUE); |
| |
| /* Set main window and sub window */ |
| set_menu_win(my_menu, my_menu_win); |
| set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1)); |
| set_menu_format(my_menu, 5, 1); |
| |
| /* Set menu mark to the string " * " */ |
| set_menu_mark(my_menu, " * "); |
| |
| /* Print a border around the main window and print a title */ |
| box(my_menu_win, 0, 0); |
| print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1)); |
| mvwaddch(my_menu_win, 2, 0, ACS_LTEE); |
| mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38); |
| mvwaddch(my_menu_win, 2, 39, ACS_RTEE); |
| |
| /* Post the menu */ |
| post_menu(my_menu); |
| wrefresh(my_menu_win); |
| |
| attron(COLOR_PAIR(2)); |
| mvprintw(LINES - 2, 0, "Use PageUp and PageDown to scoll down or up a page of items"); |
| mvprintw(LINES - 1, 0, "Arrow Keys to navigate (F1 to Exit)"); |
| attroff(COLOR_PAIR(2)); |
| refresh(); |
| |
| while((c = wgetch(my_menu_win)) != KEY_F(1)) |
| { switch(c) |
| { case KEY_DOWN: |
| menu_driver(my_menu, REQ_DOWN_ITEM); |
| break; |
| case KEY_UP: |
| menu_driver(my_menu, REQ_UP_ITEM); |
| break; |
| case KEY_NPAGE: |
| menu_driver(my_menu, REQ_SCR_DPAGE); |
| break; |
| case KEY_PPAGE: |
| menu_driver(my_menu, REQ_SCR_UPAGE); |
| break; |
| } |
| wrefresh(my_menu_win); |
| } |
| |
| /* Unpost and free all the memory taken up */ |
| unpost_menu(my_menu); |
| free_menu(my_menu); |
| for(i = 0; i < n_choices; ++i) |
| free_item(my_items[i]); |
| endwin(); |
| } |
| |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) |
| { int length, x, y; |
| float temp; |
| |
| if(win == NULL) |
| win = stdscr; |
| getyx(win, y, x); |
| if(startx != 0) |
| x = startx; |
| if(starty != 0) |
| y = starty; |
| if(width == 0) |
| width = 80; |
| |
| length = strlen(string); |
| temp = (width - length)/ 2; |
| x = startx + (int)temp; |
| wattron(win, color); |
| mvwprintw(win, y, x, "%s", string); |
| wattroff(win, color); |
| refresh(); |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>This program is self-explanatory. In this example the number of |
| choices has been increased to ten, which is larger than our sub |
| window size which can hold 6 items. This message has to be |
| explicitly conveyed to the menu system with the function |
| set_menu_format(). In here we specify the number of rows and |
| columns we want to be displayed for a single page. We can specify |
| any number of items to be shown, in the rows variables, if it is |
| less than the height of the sub window. If the key pressed by the |
| user is a PAGE UP or PAGE DOWN, the menu is scrolled a page due to |
| the requests (REQ_SCR_DPAGE and REQ_SCR_UPAGE) given to |
| menu_driver().</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MULTICOLUMN" id="MULTICOLUMN">17.6. |
| Multi Columnar Menus</a></h3> |
| <p>In the above example you have seen how to use the function |
| set_menu_format(). I didn't mention what the cols variable (third |
| parameter) does. Well, If your sub window is wide enough, you can |
| opt to display more than one item per row. This can be specified in |
| the cols variable. To make things simpler, the following example |
| doesn't show descriptions for the items.</p> |
| <div class="EXAMPLE"><a name="MMEMUCO" id="MMEMUCO"></a> |
| <p><b>Example 21. Milt Columnar Menus Example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <curses.h> |
| #include <menu.h> |
| |
| #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) |
| #define CTRLD 4 |
| |
| char *choices[] = { |
| "Choice 1", "Choice 2", "Choice 3", "Choice 4", "Choice 5", |
| "Choice 6", "Choice 7", "Choice 8", "Choice 9", "Choice 10", |
| "Choice 11", "Choice 12", "Choice 13", "Choice 14", "Choice 15", |
| "Choice 16", "Choice 17", "Choice 18", "Choice 19", "Choice 20", |
| "Exit", |
| (char *)NULL, |
| }; |
| |
| int main() |
| { ITEM **my_items; |
| int c; |
| MENU *my_menu; |
| WINDOW *my_menu_win; |
| int n_choices, i; |
| |
| /* Initialize curses */ |
| initscr(); |
| start_color(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| init_pair(1, COLOR_RED, COLOR_BLACK); |
| init_pair(2, COLOR_CYAN, COLOR_BLACK); |
| |
| /* Create items */ |
| n_choices = ARRAY_SIZE(choices); |
| my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *)); |
| for(i = 0; i < n_choices; ++i) |
| my_items[i] = new_item(choices[i], choices[i]); |
| |
| /* Crate menu */ |
| my_menu = new_menu((ITEM **)my_items); |
| |
| /* Set menu option not to show the description */ |
| menu_opts_off(my_menu, O_SHOWDESC); |
| |
| /* Create the window to be associated with the menu */ |
| my_menu_win = newwin(10, 70, 4, 4); |
| keypad(my_menu_win, TRUE); |
| |
| /* Set main window and sub window */ |
| set_menu_win(my_menu, my_menu_win); |
| set_menu_sub(my_menu, derwin(my_menu_win, 6, 68, 3, 1)); |
| set_menu_format(my_menu, 5, 3); |
| set_menu_mark(my_menu, " * "); |
| |
| /* Print a border around the main window and print a title */ |
| box(my_menu_win, 0, 0); |
| |
| attron(COLOR_PAIR(2)); |
| mvprintw(LINES - 3, 0, "Use PageUp and PageDown to scroll"); |
| mvprintw(LINES - 2, 0, "Use Arrow Keys to navigate (F1 to Exit)"); |
| attroff(COLOR_PAIR(2)); |
| refresh(); |
| |
| /* Post the menu */ |
| post_menu(my_menu); |
| wrefresh(my_menu_win); |
| |
| while((c = wgetch(my_menu_win)) != KEY_F(1)) |
| { switch(c) |
| { case KEY_DOWN: |
| menu_driver(my_menu, REQ_DOWN_ITEM); |
| break; |
| case KEY_UP: |
| menu_driver(my_menu, REQ_UP_ITEM); |
| break; |
| case KEY_LEFT: |
| menu_driver(my_menu, REQ_LEFT_ITEM); |
| break; |
| case KEY_RIGHT: |
| menu_driver(my_menu, REQ_RIGHT_ITEM); |
| break; |
| case KEY_NPAGE: |
| menu_driver(my_menu, REQ_SCR_DPAGE); |
| break; |
| case KEY_PPAGE: |
| menu_driver(my_menu, REQ_SCR_UPAGE); |
| break; |
| } |
| wrefresh(my_menu_win); |
| } |
| |
| /* Unpost and free all the memory taken up */ |
| unpost_menu(my_menu); |
| free_menu(my_menu); |
| for(i = 0; i < n_choices; ++i) |
| free_item(my_items[i]); |
| endwin(); |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>Watch the function call to set_menu_format(). It specifies the |
| number of columns to be 3, thus displaying 3 items per row. We have |
| also switched off the showing descriptions with the function |
| menu_opts_off(). There are couple of functions set_menu_opts(), |
| menu_opts_on() and menu_opts() which can be used to manipulate menu |
| options. The following menu options can be specified.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> O_ONEVALUE |
| Only one item can be selected for this menu. |
| |
| O_SHOWDESC |
| Display the item descriptions when the menu is |
| posted. |
| |
| O_ROWMAJOR |
| Display the menu in row-major order. |
| |
| O_IGNORECASE |
| Ignore the case when pattern-matching. |
| |
| O_SHOWMATCH |
| Move the cursor to within the item name while pat­ |
| tern-matching. |
| |
| O_NONCYCLIC |
| Don't wrap around next-item and previous-item, |
| requests to the other end of the menu.</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>All options are on by default. You can switch specific |
| attributes on or off with menu_opts_on() and menu_opts_off() |
| functions. You can also use set_menu_opts() to directly specify the |
| options. The argument to this function should be a OR ed value of |
| some of those above constants. The function menu_opts() can be used |
| to find out a menu's present options.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MULTIVALUEMENUS" id= |
| "MULTIVALUEMENUS">17.7. Multi Valued Menus</a></h3> |
| <p>You might be wondering what if you switch off the option |
| O_ONEVALUE. Then the menu becomes multi-valued. That means you can |
| select more than one item. This brings us to the request |
| REQ_TOGGLE_ITEM. Let's see it in action.</p> |
| <div class="EXAMPLE"><a name="MMETO" id="MMETO"></a> |
| <p><b>Example 22. Multi Valued Menus example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <curses.h> |
| #include <menu.h> |
| |
| #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) |
| #define CTRLD 4 |
| |
| char *choices[] = { |
| "Choice 1", |
| "Choice 2", |
| "Choice 3", |
| "Choice 4", |
| "Choice 5", |
| "Choice 6", |
| "Choice 7", |
| "Exit", |
| }; |
| |
| int main() |
| { ITEM **my_items; |
| int c; |
| MENU *my_menu; |
| int n_choices, i; |
| ITEM *cur_item; |
| |
| /* Initialize curses */ |
| initscr(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| |
| /* Initialize items */ |
| n_choices = ARRAY_SIZE(choices); |
| my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); |
| for(i = 0; i < n_choices; ++i) |
| my_items[i] = new_item(choices[i], choices[i]); |
| my_items[n_choices] = (ITEM *)NULL; |
| |
| my_menu = new_menu((ITEM **)my_items); |
| |
| /* Make the menu multi valued */ |
| menu_opts_off(my_menu, O_ONEVALUE); |
| |
| mvprintw(LINES - 3, 0, "Use <SPACE> to select or unselect an item."); |
| mvprintw(LINES - 2, 0, "<ENTER> to see presently selected items(F1 to Exit)"); |
| post_menu(my_menu); |
| refresh(); |
| |
| while((c = getch()) != KEY_F(1)) |
| { switch(c) |
| { case KEY_DOWN: |
| menu_driver(my_menu, REQ_DOWN_ITEM); |
| break; |
| case KEY_UP: |
| menu_driver(my_menu, REQ_UP_ITEM); |
| break; |
| case ' ': |
| menu_driver(my_menu, REQ_TOGGLE_ITEM); |
| break; |
| case 10: /* Enter */ |
| { char temp[200]; |
| ITEM **items; |
| |
| items = menu_items(my_menu); |
| temp[0] = '\0'; |
| for(i = 0; i < item_count(my_menu); ++i) |
| if(item_value(items[i]) == TRUE) |
| { strcat(temp, item_name(items[i])); |
| strcat(temp, " "); |
| } |
| move(20, 0); |
| clrtoeol(); |
| mvprintw(20, 0, temp); |
| refresh(); |
| } |
| break; |
| } |
| } |
| |
| free_item(my_items[0]); |
| free_item(my_items[1]); |
| free_menu(my_menu); |
| endwin(); |
| } |
| </span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>Whew, A lot of new functions. Let's take them one after another. |
| Firstly, the REQ_TOGGLE_ITEM. In a multi-valued menu, the user |
| should be allowed to select or un select more than one item. The |
| request REQ_TOGGLE_ITEM toggles the present selection. In this case |
| when space is pressed REQ_TOGGLE_ITEM request is sent to |
| menu_driver to achieve the result.</p> |
| <p>Now when the user presses <ENTER> we show the items he |
| presently selected. First we find out the items associated with the |
| menu using the function menu_items(). Then we loop through the |
| items to find out if the item is selected or not. The function |
| item_value() returns TRUE if an item is selected. The function |
| item_count() returns the number of items in the menu. The item name |
| can be found with item_name(). You can also find the description |
| associated with an item using item_description().</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MENUOPT" id="MENUOPT">17.8. Menu |
| Options</a></h3> |
| <p>Well, by this time you must be itching for some difference in |
| your menu, with lots of functionality. I know. You want Colors !!!. |
| You want to create nice menus similar to those text mode <a href= |
| "http://www.jersey.net/~debinjoe/games/" target="_top">dos |
| games</a>. The functions set_menu_fore() and set_menu_back() can be |
| used to change the attribute of the selected item and unselected |
| item. The names are misleading. They don't change menu's foreground |
| or background which would have been useless.</p> |
| <p>The function set_menu_grey() can be used to set the display |
| attribute for the non-selectable items in the menu. This brings us |
| to the interesting option for an item the one and only |
| O_SELECTABLE. We can turn it off by the function item_opts_off() |
| and after that that item is not selectable. It's like a grayed item |
| in those fancy windows menus. Let's put these concepts in practice |
| with this example</p> |
| <div class="EXAMPLE"><a name="MMEAT" id="MMEAT"></a> |
| <p><b>Example 23. Menu Options example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <menu.h> |
| |
| #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) |
| #define CTRLD 4 |
| |
| char *choices[] = { |
| "Choice 1", |
| "Choice 2", |
| "Choice 3", |
| "Choice 4", |
| "Choice 5", |
| "Choice 6", |
| "Choice 7", |
| "Exit", |
| }; |
| |
| int main() |
| { ITEM **my_items; |
| int c; |
| MENU *my_menu; |
| int n_choices, i; |
| ITEM *cur_item; |
| |
| /* Initialize curses */ |
| initscr(); |
| start_color(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| init_pair(1, COLOR_RED, COLOR_BLACK); |
| init_pair(2, COLOR_GREEN, COLOR_BLACK); |
| init_pair(3, COLOR_MAGENTA, COLOR_BLACK); |
| |
| /* Initialize items */ |
| n_choices = ARRAY_SIZE(choices); |
| my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); |
| for(i = 0; i < n_choices; ++i) |
| my_items[i] = new_item(choices[i], choices[i]); |
| my_items[n_choices] = (ITEM *)NULL; |
| item_opts_off(my_items[3], O_SELECTABLE); |
| item_opts_off(my_items[6], O_SELECTABLE); |
| |
| /* Create menu */ |
| my_menu = new_menu((ITEM **)my_items); |
| |
| /* Set fore ground and back ground of the menu */ |
| set_menu_fore(my_menu, COLOR_PAIR(1) | A_REVERSE); |
| set_menu_back(my_menu, COLOR_PAIR(2)); |
| set_menu_grey(my_menu, COLOR_PAIR(3)); |
| |
| /* Post the menu */ |
| mvprintw(LINES - 3, 0, "Press <ENTER> to see the option selected"); |
| mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)"); |
| post_menu(my_menu); |
| refresh(); |
| |
| while((c = getch()) != KEY_F(1)) |
| { switch(c) |
| { case KEY_DOWN: |
| menu_driver(my_menu, REQ_DOWN_ITEM); |
| break; |
| case KEY_UP: |
| menu_driver(my_menu, REQ_UP_ITEM); |
| break; |
| case 10: /* Enter */ |
| move(20, 0); |
| clrtoeol(); |
| mvprintw(20, 0, "Item selected is : %s", |
| item_name(current_item(my_menu))); |
| pos_menu_cursor(my_menu); |
| break; |
| } |
| } |
| unpost_menu(my_menu); |
| for(i = 0; i < n_choices; ++i) |
| free_item(my_items[i]); |
| free_menu(my_menu); |
| endwin(); |
| } |
| </span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MENUUSERPTR" id="MENUUSERPTR">17.9. The |
| useful User Pointer</a></h3> |
| <p>We can associate a user pointer with each item in the menu. It |
| works the same way as user pointer in panels. It's not touched by |
| menu system. You can store any thing you like in that. I usually |
| use it to store the function to be executed when the menu option is |
| chosen (It's selected and may be the user pressed |
| <ENTER>);</p> |
| <div class="EXAMPLE"><a name="MMEUS" id="MMEUS"></a> |
| <p><b>Example 24. Menu User Pointer Usage</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <curses.h> |
| #include <menu.h> |
| |
| #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) |
| #define CTRLD 4 |
| |
| char *choices[] = { |
| "Choice 1", |
| "Choice 2", |
| "Choice 3", |
| "Choice 4", |
| "Choice 5", |
| "Choice 6", |
| "Choice 7", |
| "Exit", |
| }; |
| void func(char *name); |
| |
| int main() |
| { ITEM **my_items; |
| int c; |
| MENU *my_menu; |
| int n_choices, i; |
| ITEM *cur_item; |
| |
| /* Initialize curses */ |
| initscr(); |
| start_color(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| init_pair(1, COLOR_RED, COLOR_BLACK); |
| init_pair(2, COLOR_GREEN, COLOR_BLACK); |
| init_pair(3, COLOR_MAGENTA, COLOR_BLACK); |
| |
| /* Initialize items */ |
| n_choices = ARRAY_SIZE(choices); |
| my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); |
| for(i = 0; i < n_choices; ++i) |
| { my_items[i] = new_item(choices[i], choices[i]); |
| /* Set the user pointer */ |
| set_item_userptr(my_items[i], func); |
| } |
| my_items[n_choices] = (ITEM *)NULL; |
| |
| /* Create menu */ |
| my_menu = new_menu((ITEM **)my_items); |
| |
| /* Post the menu */ |
| mvprintw(LINES - 3, 0, "Press <ENTER> to see the option selected"); |
| mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)"); |
| post_menu(my_menu); |
| refresh(); |
| |
| while((c = getch()) != KEY_F(1)) |
| { switch(c) |
| { case KEY_DOWN: |
| menu_driver(my_menu, REQ_DOWN_ITEM); |
| break; |
| case KEY_UP: |
| menu_driver(my_menu, REQ_UP_ITEM); |
| break; |
| case 10: /* Enter */ |
| { ITEM *cur; |
| void (*p)(char *); |
| |
| cur = current_item(my_menu); |
| p = item_userptr(cur); |
| p((char *)item_name(cur)); |
| pos_menu_cursor(my_menu); |
| break; |
| } |
| break; |
| } |
| } |
| unpost_menu(my_menu); |
| for(i = 0; i < n_choices; ++i) |
| free_item(my_items[i]); |
| free_menu(my_menu); |
| endwin(); |
| } |
| |
| void func(char *name) |
| { move(20, 0); |
| clrtoeol(); |
| mvprintw(20, 0, "Item selected is : %s", name); |
| } </span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="FORMS" id="FORMS">18. Forms |
| Library</a></h2> |
| <p>Well. If you have seen those forms on web pages which take input |
| from users and do various kinds of things, you might be wondering |
| how would any one create such forms in text mode display. It's |
| quite difficult to write those nifty forms in plain ncurses. Forms |
| library tries to provide a basic frame work to build and maintain |
| forms with ease. It has lot of features(functions) which manage |
| validation, dynamic expansion of fields etc.. Let's see it in full |
| flow.</p> |
| <p>A form is a collection of fields; each field can be either a |
| label(static text) or a data-entry location. The forms also library |
| provides functions to divide forms into multiple pages.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="FORMBASICS" id="FORMBASICS">18.1. The |
| Basics</a></h3> |
| <p>Forms are created in much the same way as menus. First the |
| fields related to the form are created with new_field(). You can |
| set options for the fields, so that they can be displayed with some |
| fancy attributes, validated before the field looses focus etc.. |
| Then the fields are attached to form. After this, the form can be |
| posted to display and is ready to receive inputs. On the similar |
| lines to menu_driver(), the form is manipulated with form_driver(). |
| We can send requests to form_driver to move focus to a certain |
| field, move cursor to end of the field etc.. After the user enters |
| values in the fields and validation done, form can be unposted and |
| memory allocated can be freed.</p> |
| <p>The general flow of control of a forms program looks like |
| this.</p> |
| <ol type="1"> |
| <li> |
| <p>Initialize curses</p> |
| </li> |
| <li> |
| <p>Create fields using new_field(). You can specify the height and |
| width of the field, and its position on the form.</p> |
| </li> |
| <li> |
| <p>Create the forms with new_form() by specifying the fields to be |
| attached with.</p> |
| </li> |
| <li> |
| <p>Post the form with form_post() and refresh the screen.</p> |
| </li> |
| <li> |
| <p>Process the user requests with a loop and do necessary updates |
| to form with form_driver.</p> |
| </li> |
| <li> |
| <p>Unpost the menu with form_unpost()</p> |
| </li> |
| <li> |
| <p>Free the memory allocated to menu by free_form()</p> |
| </li> |
| <li> |
| <p>Free the memory allocated to the items with free_field()</p> |
| </li> |
| <li> |
| <p>End curses</p> |
| </li> |
| </ol> |
| <p>As you can see, working with forms library is much similar to |
| handling menu library. The following examples will explore various |
| aspects of form processing. Let's start the journey with a simple |
| example. first.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="COMPILEFORMS" id="COMPILEFORMS">18.2. |
| Compiling With the Forms Library</a></h3> |
| <p>To use forms library functions, you have to include form.h and |
| to link the program with forms library the flag -lform should be |
| added along with -lncurses in that order.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"> #include <form.h> |
| . |
| . |
| . |
| |
| compile and link: gcc <program file> -lform -lncurses</font> |
| </pre></td> |
| </tr> |
| </table> |
| <div class="EXAMPLE"><a name="FFOSI" id="FFOSI"></a> |
| <p><b>Example 25. Forms Basics</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <form.h> |
| |
| int main() |
| { FIELD *field[3]; |
| FORM *my_form; |
| int ch; |
| |
| /* Initialize curses */ |
| initscr(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| |
| /* Initialize the fields */ |
| field[0] = new_field(1, 10, 4, 18, 0, 0); |
| field[1] = new_field(1, 10, 6, 18, 0, 0); |
| field[2] = NULL; |
| |
| /* Set field options */ |
| set_field_back(field[0], A_UNDERLINE); /* Print a line for the option */ |
| field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */ |
| /* Field is filled up */ |
| set_field_back(field[1], A_UNDERLINE); |
| field_opts_off(field[1], O_AUTOSKIP); |
| |
| /* Create the form and post it */ |
| my_form = new_form(field); |
| post_form(my_form); |
| refresh(); |
| |
| mvprintw(4, 10, "Value 1:"); |
| mvprintw(6, 10, "Value 2:"); |
| refresh(); |
| |
| /* Loop through to get user requests */ |
| while((ch = getch()) != KEY_F(1)) |
| { switch(ch) |
| { case KEY_DOWN: |
| /* Go to next field */ |
| form_driver(my_form, REQ_NEXT_FIELD); |
| /* Go to the end of the present buffer */ |
| /* Leaves nicely at the last character */ |
| form_driver(my_form, REQ_END_LINE); |
| break; |
| case KEY_UP: |
| /* Go to previous field */ |
| form_driver(my_form, REQ_PREV_FIELD); |
| form_driver(my_form, REQ_END_LINE); |
| break; |
| default: |
| /* If this is a normal character, it gets */ |
| /* Printed */ |
| form_driver(my_form, ch); |
| break; |
| } |
| } |
| |
| /* Un post form and free the memory */ |
| unpost_form(my_form); |
| free_form(my_form); |
| free_field(field[0]); |
| free_field(field[1]); |
| |
| endwin(); |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>Above example is pretty straight forward. It creates two fields |
| with <var class="LITERAL">new_field()</var>. new_field() takes |
| height, width, starty, startx, number of offscreen rows and number |
| of additional working buffers. The fifth argument number of |
| offscreen rows specifies how much of the field to be shown. If it |
| is zero, the entire field is always displayed otherwise the form |
| will be scrollable when the user accesses not displayed parts of |
| the field. The forms library allocates one buffer per field to |
| store the data user enters. Using the last parameter to new_field() |
| we can specify it to allocate some additional buffers. These can be |
| used for any purpose you like.</p> |
| <p>After creating the fields, back ground attribute of both of them |
| is set to an underscore with set_field_back(). The AUTOSKIP option |
| is turned off using field_opts_off(). If this option is turned on, |
| focus will move to the next field in the form once the active field |
| is filled up completely.</p> |
| <p>After attaching the fields to the form, it is posted. Here on, |
| user inputs are processed in the while loop, by making |
| corresponding requests to form_driver. The details of all the |
| requests to the form_driver() are explained later.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="PLAYFIELDS" id="PLAYFIELDS">18.3. |
| Playing with Fields</a></h3> |
| <p>Each form field is associated with a lot of attributes. They can |
| be manipulated to get the required effect and to have fun !!!. So |
| why wait?</p> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="FETCHINFO" id="FETCHINFO">18.3.1. |
| Fetching Size and Location of Field</a></h4> |
| <p>The parameters we have given at the time of creation of a field |
| can be retrieved with field_info(). It returns height, width, |
| starty, startx, number of offscreen rows, and number of additional |
| buffers into the parameters given to it. It is a sort of inverse of |
| new_field().</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int field_info( FIELD *field, /* field from which to fetch */ |
| int *height, *int width, /* field size */ |
| int *top, int *left, /* upper left corner */ |
| int *offscreen, /* number of offscreen rows */ |
| int *nbuf); /* number of working buffers */</font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="MOVEFIELD" id="MOVEFIELD">18.3.2. Moving |
| the field</a></h4> |
| <p>The location of the field can be moved to a different position |
| with move_field().</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int move_field( FIELD *field, /* field to alter */ |
| int top, int left); /* new upper-left corner */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>As usual, the changed position can be queried with |
| field_infor().</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="JUSTIFYFIELD" id="JUSTIFYFIELD">18.3.3. |
| Field Justification</a></h4> |
| <p>The justification to be done for the field can be fixed using |
| the function set_field_just().</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"> int set_field_just(FIELD *field, /* field to alter */ |
| int justmode); /* mode to set */ |
| int field_just(FIELD *field); /* fetch justify mode of field */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The justification mode valued accepted and returned by these |
| functions are NO_JUSTIFICATION, JUSTIFY_RIGHT, JUSTIFY_LEFT, or |
| JUSTIFY_CENTER.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="FIELDDISPATTRIB" id= |
| "FIELDDISPATTRIB">18.3.4. Field Display Attributes</a></h4> |
| <p>As you have seen, in the above example, display attribute for |
| the fields can be set with set_field_fore() and setfield_back(). |
| These functions set foreground and background attribute of the |
| fields. You can also specify a pad character which will be filled |
| in the unfilled portion of the field. The pad character is set with |
| a call to set_field_pad(). Default pad value is a space. The |
| functions field_fore(), field_back, field_pad() can be used to |
| query the present foreground, background attributes and pad |
| character for the field. The following list gives the usage of |
| functions.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"> int set_field_fore(FIELD *field, /* field to alter */ |
| chtype attr); /* attribute to set */ |
| |
| chtype field_fore(FIELD *field); /* field to query */ |
| /* returns foreground attribute */ |
| |
| int set_field_back(FIELD *field, /* field to alter */ |
| chtype attr); /* attribute to set */ |
| |
| chtype field_back(FIELD *field); /* field to query */ |
| /* returns background attribute */ |
| |
| int set_field_pad(FIELD *field, /* field to alter */ |
| int pad); /* pad character to set */ |
| |
| chtype field_pad(FIELD *field); /* field to query */ |
| /* returns present pad character */ </font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>Though above functions seem quite simple, using colors with |
| set_field_fore() may be frustrating in the beginning. Let me first |
| explain about foreground and background attributes of a field. The |
| foreground attribute is associated with the character. That means a |
| character in the field is printed with the attribute you have set |
| with set_field_fore(). Background attribute is the attribute used |
| to fill background of field, whether any character is there or not. |
| So what about colors? Since colors are always defined in pairs, |
| what is the right way to display colored fields? Here's an example |
| clarifying color attributes.</p> |
| <div class="EXAMPLE"><a name="FFOAT" id="FFOAT"></a> |
| <p><b>Example 26. Form Attributes example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <form.h> |
| |
| int main() |
| { FIELD *field[3]; |
| FORM *my_form; |
| int ch; |
| |
| /* Initialize curses */ |
| initscr(); |
| start_color(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| |
| /* Initialize few color pairs */ |
| init_pair(1, COLOR_WHITE, COLOR_BLUE); |
| init_pair(2, COLOR_WHITE, COLOR_BLUE); |
| |
| /* Initialize the fields */ |
| field[0] = new_field(1, 10, 4, 18, 0, 0); |
| field[1] = new_field(1, 10, 6, 18, 0, 0); |
| field[2] = NULL; |
| |
| /* Set field options */ |
| set_field_fore(field[0], COLOR_PAIR(1));/* Put the field with blue background */ |
| set_field_back(field[0], COLOR_PAIR(2));/* and white foreground (characters */ |
| /* are printed in white */ |
| field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */ |
| /* Field is filled up */ |
| set_field_back(field[1], A_UNDERLINE); |
| field_opts_off(field[1], O_AUTOSKIP); |
| |
| /* Create the form and post it */ |
| my_form = new_form(field); |
| post_form(my_form); |
| refresh(); |
| |
| set_current_field(my_form, field[0]); /* Set focus to the colored field */ |
| mvprintw(4, 10, "Value 1:"); |
| mvprintw(6, 10, "Value 2:"); |
| mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields"); |
| refresh(); |
| |
| /* Loop through to get user requests */ |
| while((ch = getch()) != KEY_F(1)) |
| { switch(ch) |
| { case KEY_DOWN: |
| /* Go to next field */ |
| form_driver(my_form, REQ_NEXT_FIELD); |
| /* Go to the end of the present buffer */ |
| /* Leaves nicely at the last character */ |
| form_driver(my_form, REQ_END_LINE); |
| break; |
| case KEY_UP: |
| /* Go to previous field */ |
| form_driver(my_form, REQ_PREV_FIELD); |
| form_driver(my_form, REQ_END_LINE); |
| break; |
| default: |
| /* If this is a normal character, it gets */ |
| /* Printed */ |
| form_driver(my_form, ch); |
| break; |
| } |
| } |
| |
| /* Un post form and free the memory */ |
| unpost_form(my_form); |
| free_form(my_form); |
| free_field(field[0]); |
| free_field(field[1]); |
| |
| endwin(); |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>Play with the color pairs and try to understand the foreground |
| and background attributes. In my programs using color attributes, I |
| usually set only the background with set_field_back(). Curses |
| simply doesn't allow defining individual color attributes.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="FIELDOPTIONBITS" id= |
| "FIELDOPTIONBITS">18.3.5. Field Option Bits</a></h4> |
| <p>There is also a large collection of field option bits you can |
| set to control various aspects of forms processing. You can |
| manipulate them with these functions:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_field_opts(FIELD *field, /* field to alter */ |
| int attr); /* attribute to set */ |
| |
| int field_opts_on(FIELD *field, /* field to alter */ |
| int attr); /* attributes to turn on */ |
| |
| int field_opts_off(FIELD *field, /* field to alter */ |
| int attr); /* attributes to turn off */ |
| |
| int field_opts(FIELD *field); /* field to query */ </font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The function set_field_opts() can be used to directly set |
| attributes of a field or you can choose to switch a few attributes |
| on and off with field_opts_on() and field_opts_off() selectively. |
| Anytime you can query the attributes of a field with field_opts(). |
| The following is the list of available options. By default, all |
| options are on.</p> |
| <div class="VARIABLELIST"> |
| <dl> |
| <dt>O_VISIBLE</dt> |
| <dd> |
| <p>Controls whether the field is visible on the screen. Can be used |
| during form processing to hide or pop up fields depending on the |
| value of parent fields.</p> |
| </dd> |
| <dt>O_ACTIVE</dt> |
| <dd> |
| <p>Controls whether the field is active during forms processing |
| (i.e. visited by form navigation keys). Can be used to make labels |
| or derived fields with buffer values alterable by the forms |
| application, not the user.</p> |
| </dd> |
| <dt>O_PUBLIC</dt> |
| <dd> |
| <p>Controls whether data is displayed during field entry. If this |
| option is turned off on a field, the library will accept and edit |
| data in that field, but it will not be displayed and the visible |
| field cursor will not move. You can turn off the O_PUBLIC bit to |
| define password fields.</p> |
| </dd> |
| <dt>O_EDIT</dt> |
| <dd> |
| <p>Controls whether the field's data can be modified. When this |
| option is off, all editing requests except <var class= |
| "LITERAL">REQ_PREV_CHOICE</var> and <var class= |
| "LITERAL">REQ_NEXT_CHOICE</var>will fail. Such read-only fields may |
| be useful for help messages.</p> |
| </dd> |
| <dt>O_WRAP</dt> |
| <dd> |
| <p>Controls word-wrapping in multi-line fields. Normally, when any |
| character of a (blank-separated) word reaches the end of the |
| current line, the entire word is wrapped to the next line (assuming |
| there is one). When this option is off, the word will be split |
| across the line break.</p> |
| </dd> |
| <dt>O_BLANK</dt> |
| <dd> |
| <p>Controls field blanking. When this option is on, entering a |
| character at the first field position erases the entire field |
| (except for the just-entered character).</p> |
| </dd> |
| <dt>O_AUTOSKIP</dt> |
| <dd> |
| <p>Controls automatic skip to next field when this one fills. |
| Normally, when the forms user tries to type more data into a field |
| than will fit, the editing location jumps to next field. When this |
| option is off, the user's cursor will hang at the end of the field. |
| This option is ignored in dynamic fields that have not reached |
| their size limit.</p> |
| </dd> |
| <dt>O_NULLOK</dt> |
| <dd> |
| <p>Controls whether validation is applied to blank fields. |
| Normally, it is not; the user can leave a field blank without |
| invoking the usual validation check on exit. If this option is off |
| on a field, exit from it will invoke a validation check.</p> |
| </dd> |
| <dt>O_PASSOK</dt> |
| <dd> |
| <p>Controls whether validation occurs on every exit, or only after |
| the field is modified. Normally the latter is true. Setting |
| O_PASSOK may be useful if your field's validation function may |
| change during forms processing.</p> |
| </dd> |
| <dt>O_STATIC</dt> |
| <dd> |
| <p>Controls whether the field is fixed to its initial dimensions. |
| If you turn this off, the field becomes dynamic and will stretch to |
| fit entered data.</p> |
| </dd> |
| </dl> |
| </div> |
| <p>A field's options cannot be changed while the field is currently |
| selected. However, options may be changed on posted fields that are |
| not current.</p> |
| <p>The option values are bit-masks and can be composed with |
| logical-or in the obvious way. You have seen the usage of switching |
| off O_AUTOSKIP option. The following example clarifies usage of |
| some more options. Other options are explained where |
| appropriate.</p> |
| <div class="EXAMPLE"><a name="FFOOP" id="FFOOP"></a> |
| <p><b>Example 27. Field Options Usage example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <form.h> |
| |
| #define STARTX 15 |
| #define STARTY 4 |
| #define WIDTH 25 |
| |
| #define N_FIELDS 3 |
| |
| int main() |
| { FIELD *field[N_FIELDS]; |
| FORM *my_form; |
| int ch, i; |
| |
| /* Initialize curses */ |
| initscr(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| |
| /* Initialize the fields */ |
| for(i = 0; i < N_FIELDS - 1; ++i) |
| field[i] = new_field(1, WIDTH, STARTY + i * 2, STARTX, 0, 0); |
| field[N_FIELDS - 1] = NULL; |
| |
| /* Set field options */ |
| set_field_back(field[1], A_UNDERLINE); /* Print a line for the option */ |
| |
| field_opts_off(field[0], O_ACTIVE); /* This field is a static label */ |
| field_opts_off(field[1], O_PUBLIC); /* This filed is like a password field*/ |
| field_opts_off(field[1], O_AUTOSKIP); /* To avoid entering the same field */ |
| /* after last character is entered */ |
| |
| /* Create the form and post it */ |
| my_form = new_form(field); |
| post_form(my_form); |
| refresh(); |
| |
| set_field_just(field[0], JUSTIFY_CENTER); /* Center Justification */ |
| set_field_buffer(field[0], 0, "This is a static Field"); |
| /* Initialize the field */ |
| mvprintw(STARTY, STARTX - 10, "Field 1:"); |
| mvprintw(STARTY + 2, STARTX - 10, "Field 2:"); |
| refresh(); |
| |
| /* Loop through to get user requests */ |
| while((ch = getch()) != KEY_F(1)) |
| { switch(ch) |
| { case KEY_DOWN: |
| /* Go to next field */ |
| form_driver(my_form, REQ_NEXT_FIELD); |
| /* Go to the end of the present buffer */ |
| /* Leaves nicely at the last character */ |
| form_driver(my_form, REQ_END_LINE); |
| break; |
| case KEY_UP: |
| /* Go to previous field */ |
| form_driver(my_form, REQ_PREV_FIELD); |
| form_driver(my_form, REQ_END_LINE); |
| break; |
| default: |
| /* If this is a normal character, it gets */ |
| /* Printed */ |
| form_driver(my_form, ch); |
| break; |
| } |
| } |
| |
| /* Un post form and free the memory */ |
| unpost_form(my_form); |
| free_form(my_form); |
| free_field(field[0]); |
| free_field(field[1]); |
| |
| endwin(); |
| return 0; |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <p>This example, though useless, shows the usage of options. If |
| used properly, they can present information very effectively in a |
| form. The second field being not O_PUBLIC, does not show the |
| characters you are typing.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="FIELDSTATUS" id="FIELDSTATUS">18.3.6. |
| Field Status</a></h4> |
| <p>The field status specifies whether the field has got edited or |
| not. It is initially set to FALSE and when user enters something |
| and the data buffer gets modified it becomes TRUE. So a field's |
| status can be queried to find out whether it has been modified or |
| not. The following functions can assist in those operations.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_field_status(FIELD *field, /* field to alter */ |
| int status); /* status to set */ |
| |
| int field_status(FIELD *field); /* fetch status of field */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>It's better to check the field's status only after after leaving |
| the field, as data buffer might not have been updated yet as the |
| validation is still due. To guarantee that right status is |
| returned, call field_status() either (1) in the field's exit |
| validation check routine, (2) from the field's or form's |
| initialization or termination hooks, or (3) just after a |
| REQ_VALIDATION request has been processed by the forms driver</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="FIELDUSERPTR" id="FIELDUSERPTR">18.3.7. |
| Field User Pointer</a></h4> |
| <p>Every field structure contains one pointer that can be used by |
| the user for various purposes. It is not touched by forms library |
| and can be used for any purpose by the user. The following |
| functions set and fetch user pointer.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000">int set_field_userptr(FIELD *field, |
| char *userptr); /* the user pointer you wish to associate */ |
| /* with the field */ |
| |
| char *field_userptr(FIELD *field); /* fetch user pointer of the field */</font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="VARIABLESIZEFIELDS" id= |
| "VARIABLESIZEFIELDS">18.3.8. Variable-Sized Fields</a></h4> |
| <p>If you want a dynamically changing field with variable width, |
| this is the feature you want to put to full use. This will allow |
| the user to enter more data than the original size of the field and |
| let the field grow. According to the field orientation it will |
| scroll horizontally or vertically to incorporate the new data.</p> |
| <p>To make a field dynamically growable, the option O_STATIC should |
| be turned off. This can be done with a</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"> field_opts_off(field_pointer, O_STATIC);</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>But it's usually not advisable to allow a field to grow |
| infinitely. You can set a maximum limit to the growth of the field |
| with</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_max_field(FIELD *field, /* Field on which to operate */ |
| int max_growth); /* maximum growth allowed for the field */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The field info for a dynamically growable field can be retrieved |
| by</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int dynamic_field_info( FIELD *field, /* Field on which to operate */ |
| int *prows, /* number of rows will be filled in this */ |
| int *pcols, /* number of columns will be filled in this*/ |
| int *pmax) /* maximum allowable growth will be filled */ |
| /* in this */</font> |
| </pre></td> |
| </tr> |
| </table> |
| Though field_info work as usual, it is advisable to use this |
| function to get the proper attributes of a dynamically growable |
| field. |
| <p>Recall the library routine new_field; a new field created with |
| height set to one will be defined to be a one line field. A new |
| field created with height greater than one will be defined to be a |
| multi line field.</p> |
| <p>A one line field with O_STATIC turned off (dynamically growable |
| field) will contain a single fixed row, but the number of columns |
| can increase if the user enters more data than the initial field |
| will hold. The number of columns displayed will remain fixed and |
| the additional data will scroll horizontally.</p> |
| <p>A multi line field with O_STATIC turned off (dynamically |
| growable field) will contain a fixed number of columns, but the |
| number of rows can increase if the user enters more data than the |
| initial field will hold. The number of rows displayed will remain |
| fixed and the additional data will scroll vertically.</p> |
| <p>The above two paragraphs pretty much describe a dynamically |
| growable field's behavior. The way other parts of forms library |
| behaves is described below:</p> |
| <ol type="1"> |
| <li> |
| <p>The field option O_AUTOSKIP will be ignored if the option |
| O_STATIC is off and there is no maximum growth specified for the |
| field. Currently, O_AUTOSKIP generates an automatic REQ_NEXT_FIELD |
| form driver request when the user types in the last character |
| position of a field. On a growable field with no maximum growth |
| specified, there is no last character position. If a maximum growth |
| is specified, the O_AUTOSKIP option will work as normal if the |
| field has grown to its maximum size.</p> |
| </li> |
| <li> |
| <p>The field justification will be ignored if the option O_STATIC |
| is off. Currently, set_field_just can be used to JUSTIFY_LEFT, |
| JUSTIFY_RIGHT, JUSTIFY_CENTER the contents of a one line field. A |
| growable one line field will, by definition, grow and scroll |
| horizontally and may contain more data than can be justified. The |
| return from field_just will be unchanged.</p> |
| </li> |
| <li> |
| <p>The overloaded form driver request REQ_NEW_LINE will operate the |
| same way regardless of the O_NL_OVERLOAD form option if the field |
| option O_STATIC is off and there is no maximum growth specified for |
| the field. Currently, if the form option O_NL_OVERLOAD is on, |
| REQ_NEW_LINE implicitly generates a REQ_NEXT_FIELD if called from |
| the last line of a field. If a field can grow without bound, there |
| is no last line, so REQ_NEW_LINE will never implicitly generate a |
| REQ_NEXT_FIELD. If a maximum growth limit is specified and the |
| O_NL_OVERLOAD form option is on, REQ_NEW_LINE will only implicitly |
| generate REQ_NEXT_FIELD if the field has grown to its maximum size |
| and the user is on the last line.</p> |
| </li> |
| <li> |
| <p>The library call dup_field will work as usual; it will duplicate |
| the field, including the current buffer size and contents of the |
| field being duplicated. Any specified maximum growth will also be |
| duplicated.</p> |
| </li> |
| <li> |
| <p>The library call link_field will work as usual; it will |
| duplicate all field attributes and share buffers with the field |
| being linked. If the O_STATIC field option is subsequently changed |
| by a field sharing buffers, how the system reacts to an attempt to |
| enter more data into the field than the buffer will currently hold |
| will depend on the setting of the option in the current field.</p> |
| </li> |
| <li> |
| <p>The library call field_info will work as usual; the variable |
| nrow will contain the value of the original call to new_field. The |
| user should use dynamic_field_info, described above, to query the |
| current size of the buffer.</p> |
| </li> |
| </ol> |
| <p>Some of the above points make sense only after explaining form |
| driver. We will be looking into that in next few sections.</p> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="FORMWINDOWS" id="FORMWINDOWS">18.4. Form |
| Windows</a></h3> |
| <p>The form windows concept is pretty much similar to menu windows. |
| Every form is associated with a main window and a sub window. The |
| form main window displays any title or border associated or |
| whatever the user wishes. Then the sub window contains all the |
| fields and displays them according to their position. This gives |
| the flexibility of manipulating fancy form displaying very |
| easily.</p> |
| <p>Since this is pretty much similar to menu windows, I am |
| providing an example with out much explanation. The functions are |
| similar and they work the same way.</p> |
| <div class="EXAMPLE"><a name="FFOWI" id="FFOWI"></a> |
| <p><b>Example 28. Form Windows Example</b></p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000"><span class= |
| "INLINEMEDIAOBJECT">#include <form.h> |
| |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); |
| |
| int main() |
| { |
| FIELD *field[3]; |
| FORM *my_form; |
| WINDOW *my_form_win; |
| int ch, rows, cols; |
| |
| /* Initialize curses */ |
| initscr(); |
| start_color(); |
| cbreak(); |
| noecho(); |
| keypad(stdscr, TRUE); |
| |
| /* Initialize few color pairs */ |
| init_pair(1, COLOR_RED, COLOR_BLACK); |
| |
| /* Initialize the fields */ |
| field[0] = new_field(1, 10, 6, 1, 0, 0); |
| field[1] = new_field(1, 10, 8, 1, 0, 0); |
| field[2] = NULL; |
| |
| /* Set field options */ |
| set_field_back(field[0], A_UNDERLINE); |
| field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */ |
| /* Field is filled up */ |
| set_field_back(field[1], A_UNDERLINE); |
| field_opts_off(field[1], O_AUTOSKIP); |
| |
| /* Create the form and post it */ |
| my_form = new_form(field); |
| |
| /* Calculate the area required for the form */ |
| scale_form(my_form, &rows, &cols); |
| |
| /* Create the window to be associated with the form */ |
| my_form_win = newwin(rows + 4, cols + 4, 4, 4); |
| keypad(my_form_win, TRUE); |
| |
| /* Set main window and sub window */ |
| set_form_win(my_form, my_form_win); |
| set_form_sub(my_form, derwin(my_form_win, rows, cols, 2, 2)); |
| |
| /* Print a border around the main window and print a title */ |
| box(my_form_win, 0, 0); |
| print_in_middle(my_form_win, 1, 0, cols + 4, "My Form", COLOR_PAIR(1)); |
| |
| post_form(my_form); |
| wrefresh(my_form_win); |
| |
| mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields"); |
| refresh(); |
| |
| /* Loop through to get user requests */ |
| while((ch = wgetch(my_form_win)) != KEY_F(1)) |
| { switch(ch) |
| { case KEY_DOWN: |
| /* Go to next field */ |
| form_driver(my_form, REQ_NEXT_FIELD); |
| /* Go to the end of the present buffer */ |
| /* Leaves nicely at the last character */ |
| form_driver(my_form, REQ_END_LINE); |
| break; |
| case KEY_UP: |
| /* Go to previous field */ |
| form_driver(my_form, REQ_PREV_FIELD); |
| form_driver(my_form, REQ_END_LINE); |
| break; |
| default: |
| /* If this is a normal character, it gets */ |
| /* Printed */ |
| form_driver(my_form, ch); |
| break; |
| } |
| } |
| |
| /* Un post form and free the memory */ |
| unpost_form(my_form); |
| free_form(my_form); |
| free_field(field[0]); |
| free_field(field[1]); |
| |
| endwin(); |
| return 0; |
| } |
| |
| void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) |
| { int length, x, y; |
| float temp; |
| |
| if(win == NULL) |
| win = stdscr; |
| getyx(win, y, x); |
| if(startx != 0) |
| x = startx; |
| if(starty != 0) |
| y = starty; |
| if(width == 0) |
| width = 80; |
| |
| length = strlen(string); |
| temp = (width - length)/ 2; |
| x = startx + (int)temp; |
| wattron(win, color); |
| mvwprintw(win, y, x, "%s", string); |
| wattroff(win, color); |
| refresh(); |
| }</span></font> |
| </pre></td> |
| </tr> |
| </table> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="FILEDVALIDATE" id="FILEDVALIDATE">18.5. |
| Field Validation</a></h3> |
| <p>By default, a field will accept any data input by the user. It |
| is possible to attach validation to the field. Then any attempt by |
| the user to leave the field, while it contains data that doesn't |
| match the validation type will fail. Some validation types also |
| have a character-validity check for each time a character is |
| entered in the field.</p> |
| <p>Validation can be attached to a field with the following |
| function.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_field_type(FIELD *field, /* field to alter */ |
| FIELDTYPE *ftype, /* type to associate */ |
| ...); /* additional arguments*/</font> |
| </pre></td> |
| </tr> |
| </table> |
| Once set, the validation type for a field can be queried with |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">FIELDTYPE *field_type(FIELD *field); /* field to query */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The form driver validates the data in a field only when data is |
| entered by the end-user. Validation does not occur when</p> |
| <ul> |
| <li> |
| <p>the application program changes the field value by calling |
| set_field_buffer.</p> |
| </li> |
| <li> |
| <p>linked field values are changed indirectly -- by changing the |
| field to which they are linked</p> |
| </li> |
| </ul> |
| <p>The following are the pre-defined validation types. You can also |
| specify custom validation, though it's a bit tricky and |
| cumbersome.</p> |
| <h1 class="BRIDGEHEAD"><a name="AEN1069" id= |
| "AEN1069"></a>TYPE_ALPHA</h1> |
| <p>This field type accepts alphabetic data; no blanks, no digits, |
| no special characters (this is checked at character-entry time). It |
| is set up with:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_field_type(FIELD *field, /* field to alter */ |
| TYPE_ALPHA, /* type to associate */ |
| int width); /* maximum width of field */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The width argument sets a minimum width of data. The user has to |
| enter at-least width number of characters before he can leave the |
| field. Typically you'll want to set this to the field width; if |
| it's greater than the field width, the validation check will always |
| fail. A minimum width of zero makes field completion optional.</p> |
| <h1 class="BRIDGEHEAD"><a name="AEN1073" id= |
| "AEN1073"></a>TYPE_ALNUM</h1> |
| <p>This field type accepts alphabetic data and digits; no blanks, |
| no special characters (this is checked at character-entry time). It |
| is set up with:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_field_type(FIELD *field, /* field to alter */ |
| TYPE_ALNUM, /* type to associate */ |
| int width); /* maximum width of field */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The width argument sets a minimum width of data. As with |
| TYPE_ALPHA, typically you'll want to set this to the field width; |
| if it's greater than the field width, the validation check will |
| always fail. A minimum width of zero makes field completion |
| optional.</p> |
| <h1 class="BRIDGEHEAD"><a name="AEN1077" id= |
| "AEN1077"></a>TYPE_ENUM</h1> |
| <p>This type allows you to restrict a field's values to be among a |
| specified set of string values (for example, the two-letter postal |
| codes for U.S. states). It is set up with:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_field_type(FIELD *field, /* field to alter */ |
| TYPE_ENUM, /* type to associate */ |
| char **valuelist; /* list of possible values */ |
| int checkcase; /* case-sensitive? */ |
| int checkunique); /* must specify uniquely? */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The valuelist parameter must point at a NULL-terminated list of |
| valid strings. The checkcase argument, if true, makes comparison |
| with the string case-sensitive.</p> |
| <p>When the user exits a TYPE_ENUM field, the validation procedure |
| tries to complete the data in the buffer to a valid entry. If a |
| complete choice string has been entered, it is of course valid. But |
| it is also possible to enter a prefix of a valid string and have it |
| completed for you.</p> |
| <p>By default, if you enter such a prefix and it matches more than |
| one value in the string list, the prefix will be completed to the |
| first matching value. But the checkunique argument, if true, |
| requires prefix matches to be unique in order to be valid.</p> |
| <p>The REQ_NEXT_CHOICE and REQ_PREV_CHOICE input requests can be |
| particularly useful with these fields.</p> |
| <h1 class="BRIDGEHEAD"><a name="AEN1084" id= |
| "AEN1084"></a>TYPE_INTEGER</h1> |
| <p>This field type accepts an integer. It is set up as follows:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_field_type(FIELD *field, /* field to alter */ |
| TYPE_INTEGER, /* type to associate */ |
| int padding, /* # places to zero-pad to */ |
| int vmin, int vmax); /* valid range */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>Valid characters consist of an optional leading minus and |
| digits. The range check is performed on exit. If the range maximum |
| is less than or equal to the minimum, the range is ignored.</p> |
| <p>If the value passes its range check, it is padded with as many |
| leading zero digits as necessary to meet the padding argument.</p> |
| <p>A TYPE_INTEGER value buffer can conveniently be interpreted with |
| the C library function atoi(3).</p> |
| <h1 class="BRIDGEHEAD"><a name="AEN1090" id= |
| "AEN1090"></a>TYPE_NUMERIC</h1> |
| <p>This field type accepts a decimal number. It is set up as |
| follows:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_field_type(FIELD *field, /* field to alter */ |
| TYPE_NUMERIC, /* type to associate */ |
| int padding, /* # places of precision */ |
| int vmin, int vmax); /* valid range */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>Valid characters consist of an optional leading minus and |
| digits. possibly including a decimal point. The range check is |
| performed on exit. If the range maximum is less than or equal to |
| the minimum, the range is ignored.</p> |
| <p>If the value passes its range check, it is padded with as many |
| trailing zero digits as necessary to meet the padding argument.</p> |
| <p>A TYPE_NUMERIC value buffer can conveniently be interpreted with |
| the C library function atof(3).</p> |
| <h1 class="BRIDGEHEAD"><a name="AEN1096" id= |
| "AEN1096"></a>TYPE_REGEXP</h1> |
| <p>This field type accepts data matching a regular expression. It |
| is set up as follows:</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_field_type(FIELD *field, /* field to alter */ |
| TYPE_REGEXP, /* type to associate */ |
| char *regexp); /* expression to match */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The syntax for regular expressions is that of regcomp(3). The |
| check for regular-expression match is performed on exit.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="FORMDRIVER" id="FORMDRIVER">18.6. Form |
| Driver: The work horse of the forms system</a></h3> |
| <p>As in the menu system, form_driver() plays a very important role |
| in forms system. All types of requests to forms system should be |
| funneled through form_driver().</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int form_driver(FORM *form, /* form on which to operate */ |
| int request) /* form request code */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>As you have seen some of the examples above, you have to be in a |
| loop looking for user input and then decide whether it's a field |
| data or a form request. The form requests are then passed to |
| form_driver() to do the work.</p> |
| <p>The requests roughly can be divided into following categories. |
| Different requests and their usage is explained below:</p> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="PAGENAVREQ" id="PAGENAVREQ">18.6.1. Page |
| Navigation Requests</a></h4> |
| <p>These requests cause page-level moves through the form, |
| triggering display of a new form screen. A form can be made of |
| multiple pages. If you have a big form with lot of fields and |
| logical sections, then you can divide the form into pages. The |
| function set_new_page() to set a new page at the field |
| specified.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">int set_new_page(FIELD *field,/* Field at which page break to be set or unset */ |
| bool new_page_flag); /* should be TRUE to put a break */</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>The following requests allow you to move to different pages</p> |
| <ul> |
| <li> |
| <p><em>REQ_NEXT_PAGE</em> Move to the next form page.</p> |
| </li> |
| <li> |
| <p><em>REQ_PREV_PAGE</em> Move to the previous form page.</p> |
| </li> |
| <li> |
| <p><em>REQ_FIRST_PAGE</em> Move to the first form page.</p> |
| </li> |
| <li> |
| <p><em>REQ_LAST_PAGE</em> Move to the last form page.</p> |
| </li> |
| </ul> |
| <p>These requests treat the list as cyclic; that is, REQ_NEXT_PAGE |
| from the last page goes to the first, and REQ_PREV_PAGE from the |
| first page goes to the last.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="INTERFIELDNAVREQ" id= |
| "INTERFIELDNAVREQ">18.6.2. Inter-Field Navigation Requests</a></h4> |
| <p>These requests handle navigation between fields on the same |
| page.</p> |
| <ul> |
| <li> |
| <p><em>REQ_NEXT_FIELD</em> Move to next field.</p> |
| </li> |
| <li> |
| <p><em>REQ_PREV_FIELD</em> Move to previous field.</p> |
| </li> |
| <li> |
| <p><em>REQ_FIRST_FIELD</em> Move to the first field.</p> |
| </li> |
| <li> |
| <p><em>REQ_LAST_FIELD</em> Move to the last field.</p> |
| </li> |
| <li> |
| <p><em>REQ_SNEXT_FIELD</em> Move to sorted next field.</p> |
| </li> |
| <li> |
| <p><em>REQ_SPREV_FIELD</em> Move to sorted previous field.</p> |
| </li> |
| <li> |
| <p><em>REQ_SFIRST_FIELD</em> Move to the sorted first field.</p> |
| </li> |
| <li> |
| <p><em>REQ_SLAST_FIELD</em> Move to the sorted last field.</p> |
| </li> |
| <li> |
| <p><em>REQ_LEFT_FIELD</em> Move left to field.</p> |
| </li> |
| <li> |
| <p><em>REQ_RIGHT_FIELD</em> Move right to field.</p> |
| </li> |
| <li> |
| <p><em>REQ_UP_FIELD</em> Move up to field.</p> |
| </li> |
| <li> |
| <p><em>REQ_DOWN_FIELD</em> Move down to field.</p> |
| </li> |
| </ul> |
| <p>These requests treat the list of fields on a page as cyclic; |
| that is, REQ_NEXT_FIELD from the last field goes to the first, and |
| REQ_PREV_FIELD from the first field goes to the last. The order of |
| the fields for these (and the REQ_FIRST_FIELD and REQ_LAST_FIELD |
| requests) is simply the order of the field pointers in the form |
| array (as set up by new_form() or set_form_fields()</p> |
| <p>It is also possible to traverse the fields as if they had been |
| sorted in screen-position order, so the sequence goes left-to-right |
| and top-to-bottom. To do this, use the second group of four |
| sorted-movement requests.</p> |
| <p>Finally, it is possible to move between fields using visual |
| directions up, down, right, and left. To accomplish this, use the |
| third group of four requests. Note, however, that the position of a |
| form for purposes of these requests is its upper-left corner.</p> |
| <p>For example, suppose you have a multi-line field B, and two |
| single-line fields A and C on the same line with B, with A to the |
| left of B and C to the right of B. A REQ_MOVE_RIGHT from A will go |
| to B only if A, B, and C all share the same first line; otherwise |
| it will skip over B to C.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="INTRAFIELDNAVREQ" id= |
| "INTRAFIELDNAVREQ">18.6.3. Intra-Field Navigation Requests</a></h4> |
| <p>These requests drive movement of the edit cursor within the |
| currently selected field.</p> |
| <ul> |
| <li> |
| <p><em>REQ_NEXT_CHAR</em> Move to next character.</p> |
| </li> |
| <li> |
| <p><em>REQ_PREV_CHAR</em> Move to previous character.</p> |
| </li> |
| <li> |
| <p><em>REQ_NEXT_LINE</em> Move to next line.</p> |
| </li> |
| <li> |
| <p><em>REQ_PREV_LINE</em> Move to previous line.</p> |
| </li> |
| <li> |
| <p><em>REQ_NEXT_WORD</em> Move to next word.</p> |
| </li> |
| <li> |
| <p><em>REQ_PREV_WORD</em> Move to previous word.</p> |
| </li> |
| <li> |
| <p><em>REQ_BEG_FIELD</em> Move to beginning of field.</p> |
| </li> |
| <li> |
| <p><em>REQ_END_FIELD</em> Move to end of field.</p> |
| </li> |
| <li> |
| <p><em>REQ_BEG_LINE</em> Move to beginning of line.</p> |
| </li> |
| <li> |
| <p><em>REQ_END_LINE</em> Move to end of line.</p> |
| </li> |
| <li> |
| <p><em>REQ_LEFT_CHAR</em> Move left in field.</p> |
| </li> |
| <li> |
| <p><em>REQ_RIGHT_CHAR</em> Move right in field.</p> |
| </li> |
| <li> |
| <p><em>REQ_UP_CHAR</em> Move up in field.</p> |
| </li> |
| <li> |
| <p><em>REQ_DOWN_CHAR</em> Move down in field.</p> |
| </li> |
| </ul> |
| <p>Each word is separated from the previous and next characters by |
| whitespace. The commands to move to beginning and end of line or |
| field look for the first or last non-pad character in their |
| ranges.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="SCROLLREQ" id="SCROLLREQ">18.6.4. |
| Scrolling Requests</a></h4> |
| <p>Fields that are dynamic and have grown and fields explicitly |
| created with offscreen rows are scrollable. One-line fields scroll |
| horizontally; multi-line fields scroll vertically. Most scrolling |
| is triggered by editing and intra-field movement (the library |
| scrolls the field to keep the cursor visible). It is possible to |
| explicitly request scrolling with the following requests:</p> |
| <ul> |
| <li> |
| <p><em>REQ_SCR_FLINE</em> Scroll vertically forward a line.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_BLINE</em> Scroll vertically backward a line.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_FPAGE</em> Scroll vertically forward a page.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_BPAGE</em> Scroll vertically backward a page.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_FHPAGE</em> Scroll vertically forward half a |
| page.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_BHPAGE</em> Scroll vertically backward half a |
| page.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_FCHAR</em> Scroll horizontally forward a |
| character.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_BCHAR</em> Scroll horizontally backward a |
| character.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_HFLINE</em> Scroll horizontally one field width |
| forward.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_HBLINE</em> Scroll horizontally one field width |
| backward.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_HFHALF</em> Scroll horizontally one half field width |
| forward.</p> |
| </li> |
| <li> |
| <p><em>REQ_SCR_HBHALF</em> Scroll horizontally one half field width |
| backward.</p> |
| </li> |
| </ul> |
| <p>For scrolling purposes, a page of a field is the height of its |
| visible part.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="EDITREQ" id="EDITREQ">18.6.5. Editing |
| Requests</a></h4> |
| <p>When you pass the forms driver an ASCII character, it is treated |
| as a request to add the character to the field's data buffer. |
| Whether this is an insertion or a replacement depends on the |
| field's edit mode (insertion is the default.</p> |
| <p>The following requests support editing the field and changing |
| the edit mode:</p> |
| <ul> |
| <li> |
| <p><em>REQ_INS_MODE</em> Set insertion mode.</p> |
| </li> |
| <li> |
| <p><em>REQ_OVL_MODE</em> Set overlay mode.</p> |
| </li> |
| <li> |
| <p><em>REQ_NEW_LINE</em> New line request (see below for |
| explanation).</p> |
| </li> |
| <li> |
| <p><em>REQ_INS_CHAR</em> Insert space at character location.</p> |
| </li> |
| <li> |
| <p><em>REQ_INS_LINE</em> Insert blank line at character |
| location.</p> |
| </li> |
| <li> |
| <p><em>REQ_DEL_CHAR</em> Delete character at cursor.</p> |
| </li> |
| <li> |
| <p><em>REQ_DEL_PREV</em> Delete previous word at cursor.</p> |
| </li> |
| <li> |
| <p><em>REQ_DEL_LINE</em> Delete line at cursor.</p> |
| </li> |
| <li> |
| <p><em>REQ_DEL_WORD</em> Delete word at cursor.</p> |
| </li> |
| <li> |
| <p><em>REQ_CLR_EOL</em> Clear to end of line.</p> |
| </li> |
| <li> |
| <p><em>REQ_CLR_EOF</em> Clear to end of field.</p> |
| </li> |
| <li> |
| <p><em>REQ_CLR_FIELD</em> Clear entire field.</p> |
| </li> |
| </ul> |
| <p>The behavior of the REQ_NEW_LINE and REQ_DEL_PREV requests is |
| complicated and partly controlled by a pair of forms options. The |
| special cases are triggered when the cursor is at the beginning of |
| a field, or on the last line of the field.</p> |
| <p>First, we consider REQ_NEW_LINE:</p> |
| <p>The normal behavior of REQ_NEW_LINE in insert mode is to break |
| the current line at the position of the edit cursor, inserting the |
| portion of the current line after the cursor as a new line |
| following the current and moving the cursor to the beginning of |
| that new line (you may think of this as inserting a newline in the |
| field buffer).</p> |
| <p>The normal behavior of REQ_NEW_LINE in overlay mode is to clear |
| the current line from the position of the edit cursor to end of |
| line. The cursor is then moved to the beginning of the next |
| line.</p> |
| <p>However, REQ_NEW_LINE at the beginning of a field, or on the |
| last line of a field, instead does a REQ_NEXT_FIELD. O_NL_OVERLOAD |
| option is off, this special action is disabled.</p> |
| <p>Now, let us consider REQ_DEL_PREV:</p> |
| <p>The normal behavior of REQ_DEL_PREV is to delete the previous |
| character. If insert mode is on, and the cursor is at the start of |
| a line, and the text on that line will fit on the previous one, it |
| instead appends the contents of the current line to the previous |
| one and deletes the current line (you may think of this as deleting |
| a newline from the field buffer).</p> |
| <p>However, REQ_DEL_PREV at the beginning of a field is instead |
| treated as a REQ_PREV_FIELD.</p> |
| <p>If the O_BS_OVERLOAD option is off, this special action is |
| disabled and the forms driver just returns E_REQUEST_DENIED.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="ORDERREQ" id="ORDERREQ">18.6.6. Order |
| Requests</a></h4> |
| <p>If the type of your field is ordered, and has associated |
| functions for getting the next and previous values of the type from |
| a given value, there are requests that can fetch that value into |
| the field buffer:</p> |
| <ul> |
| <li> |
| <p><em>REQ_NEXT_CHOICE</em> Place the successor value of the |
| current value in the buffer.</p> |
| </li> |
| <li> |
| <p><em>REQ_PREV_CHOICE</em> Place the predecessor value of the |
| current value in the buffer.</p> |
| </li> |
| </ul> |
| <p>Of the built-in field types, only TYPE_ENUM has built-in |
| successor and predecessor functions. When you define a field type |
| of your own (see Custom Validation Types), you can associate our |
| own ordering functions.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="APPLICCOMMANDS" id= |
| "APPLICCOMMANDS">18.6.7. Application Commands</a></h4> |
| <p>Form requests are represented as integers above the curses value |
| greater than KEY_MAX and less than or equal to the constant |
| MAX_COMMAND. A value within this range gets ignored by |
| form_driver(). So this can be used for any purpose by the |
| application. It can be treated as an application specific action |
| and take corresponding action.</p> |
| </div> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="TOOLS" id="TOOLS">19. Tools and Widget |
| Libraries</a></h2> |
| <p>Now that you have seen the capabilities of ncurses and its |
| sister libraries, you are rolling your sleeves up and gearing for a |
| project that heavily manipulates screen. But wait.. It can be |
| pretty difficult to write and maintain complex GUI widgets in plain |
| ncurses or even with the additional libraries. There are some |
| ready-to-use tools and widget libraries that can be used instead of |
| writing your own widgets. You can use some of them, get ideas from |
| the code, or even extend them.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="CDK" id="CDK">19.1. CDK (Curses |
| Development Kit)</a></h3> |
| <p>In the author's words</p> |
| <p><em>CDK stands for 'Curses Development Kit' and it currently |
| contains 21 ready to use widgets which facilitate the speedy |
| development of full screen curses programs.</em></p> |
| <p>The kit provides some useful widgets, which can be used in your |
| programs directly. It's pretty well written and the documentation |
| is very good. The examples in the examples directory can be a good |
| place to start for beginners. The CDK can be downloaded from |
| <a href="http://invisible-island.net/cdk/" target= |
| "_top">http://invisible-island.net/cdk/</a> . Follow the |
| instructions in README file to install it.</p> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="WIDGETLIST" id="WIDGETLIST">19.1.1. |
| Widget List</a></h4> |
| <p>The following is the list of widgets provided with cdk and their |
| description.</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color="#000000">Widget Type Quick Description |
| =========================================================================== |
| Alphalist Allows a user to select from a list of words, with |
| the ability to narrow the search list by typing in a |
| few characters of the desired word. |
| Buttonbox This creates a multiple button widget. |
| Calendar Creates a little simple calendar widget. |
| Dialog Prompts the user with a message, and the user |
| can pick an answer from the buttons provided. |
| Entry Allows the user to enter various types of information. |
| File Selector A file selector built from Cdk base widgets. This |
| example shows how to create more complicated widgets |
| using the Cdk widget library. |
| Graph Draws a graph. |
| Histogram Draws a histogram. |
| Item List Creates a pop up field which allows the user to select |
| one of several choices in a small field. Very useful |
| for things like days of the week or month names. |
| Label Displays messages in a pop up box, or the label can be |
| considered part of the screen. |
| Marquee Displays a message in a scrolling marquee. |
| Matrix Creates a complex matrix with lots of options. |
| Menu Creates a pull-down menu interface. |
| Multiple Line Entry A multiple line entry field. Very useful |
| for long fields. (like a description |
| field) |
| Radio List Creates a radio button list. |
| Scale Creates a numeric scale. Used for allowing a user to |
| pick a numeric value and restrict them to a range of |
| values. |
| Scrolling List Creates a scrolling list/menu list. |
| Scrolling Window Creates a scrolling log file viewer. Can add |
| information into the window while its running. |
| A good widget for displaying the progress of |
| something. (akin to a console window) |
| Selection List Creates a multiple option selection list. |
| Slider Akin to the scale widget, this widget provides a |
| visual slide bar to represent the numeric value. |
| Template Creates a entry field with character sensitive |
| positions. Used for pre-formatted fields like |
| dates and phone numbers. |
| Viewer This is a file/information viewer. Very useful |
| when you need to display loads of information. |
| ===========================================================================</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>A few of the widgets are modified by Thomas Dickey in recent |
| versions.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="CDKATTRACT" id="CDKATTRACT">19.1.2. Some |
| Attractive Features</a></h4> |
| <p>Apart from making our life easier with readily usable widgets, |
| cdk solves one frustrating problem with printing multi colored |
| strings, justified strings elegantly. Special formatting tags can |
| be embedded in the strings which are passed to CDK functions. For |
| Example</p> |
| <p>If the string</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000">"</B/1>This line should have a yellow foreground and a blue |
| background.<!1>"</font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>given as a parameter to newCDKLabel(), it prints the line with |
| yellow foreground and blue background. There are other tags |
| available for justifying string, embedding special drawing |
| characters etc.. Please refer to the man page cdk_display(3X) for |
| details. The man page explains the usage with nice examples.</p> |
| </div> |
| <div class="SECT3"> |
| <hr> |
| <h4 class="SECT3"><a name="CDKCONCLUSION" id= |
| "CDKCONCLUSION">19.1.3. Conclusion</a></h4> |
| <p>All in all, CDK is a well-written package of widgets, which if |
| used properly can form a strong frame work for developing complex |
| GUI.</p> |
| </div> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="DIALOG" id="DIALOG">19.2. The |
| dialog</a></h3> |
| <p>Long long ago, in September 1994, when few people knew linux, |
| Jeff Tranter wrote an <a href= |
| "http://www2.linuxjournal.com/lj-issues/issue5/2807.html" target= |
| "_top">article</a> on dialog in Linux Journal. He starts the |
| article with these words..</p> |
| <p><em>Linux is based on the Unix operating system, but also |
| features a number of unique and useful kernel features and |
| application programs that often go beyond what is available under |
| Unix. One little-known gem is "dialog", a utility for creating |
| professional-looking dialog boxes from within shell scripts. This |
| article presents a tutorial introduction to the dialog utility, and |
| shows examples of how and where it can be used</em></p> |
| <p>As he explains, dialog is a real gem in making |
| professional-looking dialog boxes with ease. It creates a variety |
| of dialog boxes, menus, check lists etc.. It is usually installed |
| by default. If not, you can download it from <a href= |
| "http://invisible-island.net/dialog/" target="_top">Thomas |
| Dickey</a>'s site.</p> |
| <p>The above-mentioned article gives a very good overview of its |
| uses and capabilites. The man page has more details. It can be used |
| in variety of situations. One good example is building of linux |
| kernel in text mode. Linux kernel uses a modified version of dialog |
| tailored for its needs.</p> |
| <p>dialog was initially designed to be used with shell scripts. If |
| you want to use its functionality in a c program, then you can use |
| libdialog. The documentation regarding this is sparse. Definitive |
| reference is the dialog.h header file which comes with the library. |
| You may need to hack here and there to get the required output. The |
| source is easily customizable. I have used it on a number of |
| occasions by modifying the code.</p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="PERLCURSES" id="PERLCURSES">19.3. Perl |
| Curses Modules CURSES::FORM and CURSES::WIDGETS</a></h3> |
| <p>The perl module Curses, Curses::Form and Curses::Widgets give |
| access to curses from perl. If you have curses and basic perl is |
| installed, you can get these modules from <a href= |
| "http://www.cpan.org/modules/01modules.index.html" target= |
| "_top">CPAN All Modules page</a>. Get the three zipped modules in |
| the Curses category. Once installed you can use these modules from |
| perl scripts like any other module. For more information on perl |
| modules see perlmod man page. The above modules come with good |
| documentation and they have some demo scripts to test the |
| functionality. Though the widgets provided are very rudimentary, |
| these modules provide good access to curses library from perl.</p> |
| <p>Some of my code examples are converted to perl by Anuradha |
| Ratnaweera and they are available in the <var class= |
| "LITERAL">perl</var> directory.</p> |
| <p>For more information see man pages Curses(3) , Curses::Form(3) |
| and Curses::Widgets(3). These pages are installed only when the |
| above modules are acquired and installed.</p> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="JUSTFORFUN" id="JUSTFORFUN">20. Just For |
| Fun !!!</a></h2> |
| <p>This section contains few programs written by me just for fun. |
| They don't signify a better programming practice or the best way of |
| using ncurses. They are provided here so as to allow beginners to |
| get ideas and add more programs to this section. If you have |
| written a couple of nice, simple programs in curses and want them |
| to included here, contact <a href="mailto:ppadala@gmail.com" |
| target="_top">me</a>.</p> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="GAMEOFLIFE" id="GAMEOFLIFE">20.1. The |
| Game of Life</a></h3> |
| <p>Game of life is a wonder of math. In <a href= |
| "http://www.math.com/students/wonders/life/life.html" target= |
| "_top">Paul Callahan</a>'s words</p> |
| <table border="0" bgcolor="#E0E0E0" width="100%"> |
| <tr> |
| <td> |
| <pre class="PROGRAMLISTING"> |
| <font color= |
| "#000000"><em>The Game of Life (or simply Life) is not a game in the conventional sense. There |
| are no players, and no winning or losing. Once the "pieces" are placed in the |
| starting position, the rules determine everything that happens later. |
| Nevertheless, Life is full of surprises! In most cases, it is impossible to look |
| at a starting position (or pattern) and see what will happen in the future. The |
| only way to find out is to follow the rules of the game.</em></font> |
| </pre></td> |
| </tr> |
| </table> |
| <p>This program starts with a simple inverted U pattern and shows |
| how wonderful life works. There is a lot of room for improvement in |
| the program. You can let the user enter pattern of his choice or |
| even take input from a file. You can also change rules and play |
| with a lot of variations. Search on <a href="http://www.google.com" |
| target="_top">google</a> for interesting information on game of |
| life.</p> |
| <p><em>File Path: JustForFun/life.c</em></p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="MAGIC" id="MAGIC">20.2. Magic |
| Square</a></h3> |
| <p>Magic Square, another wonder of math, is very simple to |
| understand but very difficult to make. In a magic square sum of the |
| numbers in each row, each column is equal. Even diagnol sum can be |
| equal. There are many variations which have special properties.</p> |
| <p>This program creates a simple magic square of odd order.</p> |
| <p><em>File Path: JustForFun/magic.c</em></p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="HANOI" id="HANOI">20.3. Towers of |
| Hanoi</a></h3> |
| <p>The famous towers of hanoi solver. The aim of the game is to |
| move the disks on the first peg to last peg, using middle peg as a |
| temporary stay. The catch is not to place a larger disk over a |
| small disk at any time.</p> |
| <p><em>File Path: JustForFun/hanoi.c</em></p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="QUEENS" id="QUEENS">20.4. Queens |
| Puzzle</a></h3> |
| <p>The objective of the famous N-Queen puzzle is to put N queens on |
| a N X N chess board without attacking each other.</p> |
| <p>This program solves it with a simple backtracking technique.</p> |
| <p><em>File Path: JustForFun/queens.c</em></p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="SHUFFLE" id="SHUFFLE">20.5. |
| Shuffle</a></h3> |
| <p>A fun game, if you have time to kill.</p> |
| <p><em>File Path: JustForFun/shuffle.c</em></p> |
| </div> |
| <div class="SECT2"> |
| <hr> |
| <h3 class="SECT2"><a name="TT" id="TT">20.6. Typing Tutor</a></h3> |
| <p>A simple typing tutor, I created more out of need than for ease |
| of use. If you know how to put your fingers correctly on the |
| keyboard, but lack practice, this can be helpful.</p> |
| <p><em>File Path: JustForFun/tt.c</em></p> |
| </div> |
| </div> |
| <div class="SECT1"> |
| <hr> |
| <h2 class="SECT1"><a name="REF" id="REF">21. References</a></h2> |
| <ul> |
| <li> |
| <p>NCURSES man pages</p> |
| </li> |
| <li> |
| <p>NCURSES FAQ at <a href= |
| "http://invisible-island.net/ncurses/ncurses.faq.html" target= |
| "_top">http://invisible-island.net/ncurses/ncurses.faq.html</a></p> |
| </li> |
| <li> |
| <p>Writing programs with NCURSES by Eric Raymond and Zeyd M. |
| Ben-Halim at <a href= |
| "http://invisible-island.net/ncurses/ncurses-intro.html" target= |
| "_top">http://invisible-island.net/ncurses/ncurses-intro.html</a> - |
| somewhat obsolete. I was inspired by this document and the |
| structure of this HOWTO follows from the original document</p> |
| </li> |
| </ul> |
| </div> |
| </div> |
| </body> |
| </html> |