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| <H1>curs_color 3x</H1> |
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| <PRE> |
| <!-- Manpage converted by man2html 3.0.1 --> |
| <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG> <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG> |
| |
| |
| |
| |
| </PRE> |
| <H2>NAME</H2><PRE> |
| <STRONG>start_color</STRONG>, <STRONG>init_pair</STRONG>, <STRONG>init_color</STRONG>, <STRONG>has_colors</STRONG>, |
| <STRONG>can_change_color</STRONG>, <STRONG>color_content</STRONG>, <STRONG>pair_content</STRONG>, <STRONG>COLOR_PAIR</STRONG> |
| - <STRONG>curses</STRONG> color manipulation routines |
| |
| |
| </PRE> |
| <H2>SYNOPSIS</H2><PRE> |
| <STRONG>#</STRONG> <STRONG>include</STRONG> <STRONG><curses.h></STRONG> |
| <STRONG>int</STRONG> <STRONG>start_color(void);</STRONG> |
| <STRONG>int</STRONG> <STRONG>init_pair(short</STRONG> <STRONG>pair,</STRONG> <STRONG>short</STRONG> <STRONG>f,</STRONG> <STRONG>short</STRONG> <STRONG>b);</STRONG> |
| <STRONG>int</STRONG> <STRONG>init_color(short</STRONG> <STRONG>color,</STRONG> <STRONG>short</STRONG> <STRONG>r,</STRONG> <STRONG>short</STRONG> <STRONG>g,</STRONG> <STRONG>short</STRONG> <STRONG>b);</STRONG> |
| <STRONG>bool</STRONG> <STRONG>has_colors(void);</STRONG> |
| <STRONG>bool</STRONG> <STRONG>can_change_color(void);</STRONG> |
| <STRONG>int</STRONG> <STRONG>color_content(short</STRONG> <STRONG>color,</STRONG> <STRONG>short</STRONG> <STRONG>*r,</STRONG> <STRONG>short</STRONG> <STRONG>*g,</STRONG> <STRONG>short</STRONG> |
| <STRONG>*b);</STRONG> |
| <STRONG>int</STRONG> <STRONG>pair_content(short</STRONG> <STRONG>pair,</STRONG> <STRONG>short</STRONG> <STRONG>*f,</STRONG> <STRONG>short</STRONG> <STRONG>*b);</STRONG> |
| |
| |
| </PRE> |
| <H2>DESCRIPTION</H2><PRE> |
| <STRONG>Overview</STRONG> |
| <STRONG>curses</STRONG> support color attributes on terminals with that ca- |
| pability. To use these routines <STRONG>start_color</STRONG> must be |
| called, usually right after <STRONG>initscr</STRONG>. Colors are always |
| used in pairs (referred to as color-pairs). A color-pair |
| consists of a foreground color (for characters) and a |
| background color (for the blank field on which the charac- |
| ters are displayed). A programmer initializes a color- |
| pair with the routine <STRONG>init_pair</STRONG>. After it has been ini- |
| tialized, <STRONG>COLOR_PAIR</STRONG>(<EM>n</EM>), a macro defined in <STRONG><curses.h></STRONG>, |
| can be used as a new video attribute. |
| |
| If a terminal is capable of redefining colors, the pro- |
| grammer can use the routine <STRONG>init_color</STRONG> to change the defi- |
| nition of a color. The routines <STRONG>has_colors</STRONG> and |
| <STRONG>can_change_color</STRONG> return <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>, depending on |
| whether the terminal has color capabilities and whether |
| the programmer can change the colors. The routine <STRONG>col-</STRONG> |
| <STRONG>or_content</STRONG> allows a programmer to extract the amounts of |
| red, green, and blue components in an initialized color. |
| The routine <STRONG>pair_content</STRONG> allows a programmer to find out |
| how a given color-pair is currently defined. |
| |
| <STRONG>Routine</STRONG> <STRONG>Descriptions</STRONG> |
| The <STRONG>start_color</STRONG> routine requires no arguments. It must be |
| called if the programmer wants to use colors, and before |
| any other color manipulation routine is called. It is |
| good practice to call this routine right after <STRONG>initscr</STRONG>. |
| <STRONG>start_color</STRONG> initializes eight basic colors (black, red, |
| green, yellow, blue, magenta, cyan, and white), and two |
| global variables, <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG> (respectively |
| defining the maximum number of colors and color-pairs the |
| terminal can support). It also restores the colors on the |
| terminal to the values they had when the terminal was just |
| turned on. |
| |
| The <STRONG>init_pair</STRONG> routine changes the definition of a color- |
| pair. It takes three arguments: the number of the color- |
| pair to be changed, the foreground color number, and the |
| background color number. For portable applications: |
| |
| - The value of the first argument must be between <STRONG>1</STRONG> and |
| <STRONG>COLOR_PAIRS-1</STRONG>. |
| |
| - The value of the second and third arguments must be |
| between 0 and <STRONG>COLORS</STRONG>. Color pair 0 is assumed to be |
| white on black, but is actually whatever the terminal |
| implements before color is initialized. It cannot be |
| modified by the application. |
| |
| If the color-pair was previously initialized, the screen |
| is refreshed and all occurrences of that color-pair are |
| changed to the new definition. |
| |
| As an extension, ncurses allows you to set color pair 0 |
| via the <STRONG>assume_default_colors</STRONG> routine, or to specify the |
| use of default colors (color number <STRONG>-1</STRONG>) if you first in- |
| voke the <STRONG>use_default_colors</STRONG> routine. |
| |
| The <STRONG>init_color</STRONG> routine changes the definition of a color. |
| It takes four arguments: the number of the color to be |
| changed followed by three RGB values (for the amounts of |
| red, green, and blue components). The value of the first |
| argument must be between <STRONG>0</STRONG> and <STRONG>COLORS</STRONG>. (See the section |
| <STRONG>Colors</STRONG> for the default color index.) Each of the last |
| three arguments must be a value between 0 and 1000. When |
| <STRONG>init_color</STRONG> is used, all occurrences of that color on the |
| screen immediately change to the new definition. |
| |
| The <STRONG>has_colors</STRONG> routine requires no arguments. It returns |
| <STRONG>TRUE</STRONG> if the terminal can manipulate colors; otherwise, it |
| returns <STRONG>FALSE</STRONG>. This routine facilitates writing terminal- |
| independent programs. For example, a programmer can use |
| it to decide whether to use color or some other video at- |
| tribute. |
| |
| The <STRONG>can_change_color</STRONG> routine requires no arguments. It |
| returns <STRONG>TRUE</STRONG> if the terminal supports colors and can |
| change their definitions; other, it returns <STRONG>FALSE</STRONG>. This |
| routine facilitates writing terminal-independent programs. |
| |
| The <STRONG>color_content</STRONG> routine gives programmers a way to find |
| the intensity of the red, green, and blue (RGB) components |
| in a color. It requires four arguments: the color number, |
| and three addresses of <STRONG>short</STRONG>s for storing the information |
| about the amounts of red, green, and blue components in |
| the given color. The value of the first argument must be |
| between 0 and <STRONG>COLORS</STRONG>. The values that are stored at the |
| addresses pointed to by the last three arguments are be- |
| tween 0 (no component) and 1000 (maximum amount of compo- |
| nent). |
| |
| The <STRONG>pair_content</STRONG> routine allows programmers to find out |
| what colors a given color-pair consists of. It requires |
| three arguments: the color-pair number, and two addresses |
| of <STRONG>short</STRONG>s for storing the foreground and the background |
| color numbers. The value of the first argument must be |
| between 1 and <STRONG>COLOR_PAIRS-1</STRONG>. The values that are stored |
| at the addresses pointed to by the second and third argu- |
| ments are between 0 and <STRONG>COLORS</STRONG>. |
| |
| <STRONG>Colors</STRONG> |
| In <STRONG><curses.h></STRONG> the following macros are defined. These are |
| the default colors. <STRONG>curses</STRONG> also assumes that <STRONG>COLOR_BLACK</STRONG> |
| is the default background color for all terminals. |
| |
| <STRONG>COLOR_BLACK</STRONG> |
| <STRONG>COLOR_RED</STRONG> |
| <STRONG>COLOR_GREEN</STRONG> |
| <STRONG>COLOR_YELLOW</STRONG> |
| <STRONG>COLOR_BLUE</STRONG> |
| <STRONG>COLOR_MAGENTA</STRONG> |
| <STRONG>COLOR_CYAN</STRONG> |
| <STRONG>COLOR_WHITE</STRONG> |
| |
| |
| </PRE> |
| <H2>RETURN VALUE</H2><PRE> |
| The routines <STRONG>can_change_color()</STRONG> and <STRONG>has_colors()</STRONG> return |
| <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>. |
| |
| All other routines return the integer <STRONG>ERR</STRONG> upon failure and |
| an <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than |
| <STRONG>ERR</STRONG>") upon successful completion. |
| |
| X/Open defines no error conditions. This implementation |
| will return <STRONG>ERR</STRONG> on attempts to use color values outside |
| the range 0 to COLORS-1 (except for the default colors ex- |
| tension), or use color pairs outside the range 0 to COL- |
| OR_PAIR-1. Color values used in <STRONG>init_color</STRONG> must be in the |
| range 0 to 1000. An error is returned from all functions |
| if the terminal has not been initialized. An error is re- |
| turned from secondary functions such as <STRONG>init_pair</STRONG> if |
| <STRONG>start_color</STRONG> was not called. |
| |
| <STRONG>init_color</STRONG> |
| returns an error if the terminal does not sup- |
| port this feature, e.g., if the <EM>initial-</EM> |
| <EM>ize</EM><STRONG>_</STRONG><EM>color</EM> capability is absent from the termi- |
| nal description. |
| |
| <STRONG>start_color</STRONG> |
| returns an error If the color table cannot be |
| allocated. |
| |
| |
| </PRE> |
| <H2>NOTES</H2><PRE> |
| In the <EM>ncurses</EM> implementation, there is a separate color |
| activation flag, color palette, color pairs table, and as- |
| sociated COLORS and COLOR_PAIRS counts for each screen; |
| the <STRONG>start_color</STRONG> function only affects the current screen. |
| The SVr4/XSI interface is not really designed with this in |
| mind, and historical implementations may use a single |
| shared color palette. |
| |
| Note that setting an implicit background color via a color |
| pair affects only character cells that a character write |
| operation explicitly touches. To change the background |
| color used when parts of a window are blanked by erasing |
| or scrolling operations, see <STRONG><A HREF="curs_bkgd.3x.html">curs_bkgd(3x)</A></STRONG>. |
| |
| Several caveats apply on 386 and 486 machines with VGA- |
| compatible graphics: |
| |
| - COLOR_YELLOW is actually brown. To get yellow, use |
| COLOR_YELLOW combined with the <STRONG>A_BOLD</STRONG> attribute. |
| |
| - The A_BLINK attribute should in theory cause the |
| background to go bright. This often fails to work, |
| and even some cards for which it mostly works (such |
| as the Paradise and compatibles) do the wrong thing |
| when you try to set a bright "yellow" background (you |
| get a blinking yellow foreground instead). |
| |
| - Color RGB values are not settable. |
| |
| |
| </PRE> |
| <H2>PORTABILITY</H2><PRE> |
| This implementation satisfies XSI Curses's minimum maxi- |
| mums for <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG>. |
| |
| The <STRONG>init_pair</STRONG> routine accepts negative values of fore- |
| ground and background color to support the <STRONG>use_de-</STRONG> |
| <STRONG>fault_colors</STRONG> extension, but only if that routine has been |
| first invoked. |
| |
| The assumption that <STRONG>COLOR_BLACK</STRONG> is the default background |
| color for all terminals can be modified using the <STRONG>as-</STRONG> |
| <STRONG>sume_default_colors</STRONG> extension. |
| |
| This implementation checks the pointers, e.g., for the |
| values returned by <STRONG>color_content</STRONG> and <STRONG>pair_content</STRONG>, and |
| will treat those as optional parameters when null. |
| |
| |
| </PRE> |
| <H2>SEE ALSO</H2><PRE> |
| <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG>default_col-</STRONG> |
| <STRONG><A HREF="default_colors.3x.html">ors(3x)</A></STRONG> |
| |
| |
| |
| <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG> |
| </PRE> |
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