ncurses/test/movewindow.c - nest-cam/4320010/ncurses - Git at Google

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 /*
  * $Id: movewindow.c,v 1.39 2013/05/04 19:41:02 tom Exp $
  *
  * Demonstrate move functions for windows and derived windows from the curses
  * library.
  *
  * Author: Thomas E. Dickey
  */
 /*
 derwin
 mvderwin
 subwin
 mvwin

 TODO:
     add command to reset subwindow's origin to coincide with parent.
     add command to delete subwindow (check if it has subwindows though)
  */

 #include <test.priv.h>
 #include <stdarg.h>

 #ifdef HAVE_XCURSES
 #undef derwin
 #endif

 #ifdef NCURSES_VERSION
 #define CONST_FMT const
 #else
 #define CONST_FMT		/* nothing */
 #endif

 #undef LINE_MAX

 #define LINE_MIN	2
 #define LINE_MAX	(LINES - 2)
 #define COL_MIN		2
 #define COL_MAX		(COLS - 2)

 typedef struct {
     int y, x;
 } PAIR;

 typedef struct {
     WINDOW *parent;		/* need this since WINDOW->_parent is not portable */
     WINDOW *child;		/* the actual value */
 } FRAME;

 static void head_line(CONST_FMT char *fmt,...) GCC_PRINTFLIKE(1, 2);
 static void tail_line(CONST_FMT char *fmt,...) GCC_PRINTFLIKE(1, 2);

 static unsigned num_windows;
 static FRAME *all_windows;

 static void
 failed(const char *s)
 {
     perror(s);
     endwin();
     ExitProgram(EXIT_FAILURE);
 }

 static void
 message(int lineno, CONST_FMT char *fmt, va_list argp)
 {
     int y, x;

     getyx(stdscr, y, x);
     move(lineno, 0);
     clrtoeol();

 #ifdef HAVE_XCURSES
     {
 	char buffer[1024];
 	vsprintf(buffer, fmt, argp);
 	addstr(buffer);
     }
 #else
     vwprintw(stdscr, fmt, argp);
 #endif

     move(y, x);
     refresh();
 }

 static void
 head_line(CONST_FMT char *fmt,...)
 {
     va_list argp;

     va_start(argp, fmt);
     message(0, fmt, argp);
     va_end(argp);
 }

 static void
 tail_line(CONST_FMT char *fmt,...)
 {
     va_list argp;

     va_start(argp, fmt);
     message(LINES - 1, fmt, argp);
     va_end(argp);
 }

 /*
  * Arrow keys move cursor, return location at current on non-arrow key.
  */
 static PAIR *
 selectcell(WINDOW *parent,
 	   WINDOW *child,
 	   int uli, int ulj,
 	   int lri, int lrj,
 	   bool relative,
 	   bool * more)
 {
     static PAIR res;		/* result cell */
     int si = lri - uli + 1;	/* depth of the select area */
     int sj = lrj - ulj + 1;	/* width of the select area */
     int i = 0, j = 0;		/* offsets into the select area */

     res.y = uli;
     res.x = ulj;

     if (child != 0) {
 	if (relative) {
 	    getparyx(child, i, j);
 	} else {
 	    getbegyx(child, i, j);
 	    i -= uli + getbegy(parent);
 	    j -= ulj + getbegx(parent);
 	}
     }

     if (more)
 	*more = FALSE;

     for (;;) {
 	bool moved = FALSE;

 	tail_line("Upper left [%2d,%2d] Lower right [%2d,%2d] -> %d,%d -> %d,%d",
 		  uli, ulj,
 		  lri, lrj,
 		  i, j,
 		  uli + i, ulj + j);
 	wmove(parent, uli + i, ulj + j);

 	switch (wgetch(parent)) {
 	case KEY_UP:
 	    i += si - 1;
 	    moved = TRUE;
 	    break;
 	case KEY_DOWN:
 	    i++;
 	    moved = TRUE;
 	    break;
 	case KEY_LEFT:
 	    j += sj - 1;
 	    moved = TRUE;
 	    break;
 	case KEY_RIGHT:
 	    j++;
 	    moved = TRUE;
 	    break;
 	case QUIT:
 	case ESCAPE:
 	    return ((PAIR *) 0);
 #ifdef NCURSES_MOUSE_VERSION
 	case KEY_MOUSE:
 	    {
 		MEVENT event;

 		getmouse(&event);
 		if (event.y > uli && event.x > ulj) {
 		    if (parent != stdscr) {
 			i = event.y - getbegy(parent) - uli;
 			j = event.x - getbegx(parent) - ulj;
 		    } else {
 			i = event.y - uli;
 			j = event.x - ulj;
 		    }
 		} else {
 		    beep();
 		    break;
 		}
 	    }
 	    /* FALLTHRU */
 #endif
 	default:
 	    res.y = uli + i;
 	    res.x = ulj + j;
 	    return (&res);
 	}

 	if (si <= 0)
 	    i = 0;
 	else
 	    i %= si;

 	if (sj <= 0)
 	    j = 0;
 	else
 	    j %= sj;

 	/*
 	 * If the caller can handle continuous movement, return the result.
 	 */
 	if (moved && more) {
 	    *more = TRUE;
 	    res.y = uli + i;
 	    res.x = ulj + j;
 	    return (&res);
 	}
     }
 }

 /*
  * Ask user for a window definition.
  */
 static bool
 getwindow(WINDOW *parent, PAIR * ul, PAIR * lr)
 {
     int min_col = (parent == stdscr) ? COL_MIN : 0;
     int max_col = (parent == stdscr) ? COL_MAX : getmaxx(parent);
     int min_line = (parent == stdscr) ? LINE_MIN : 0;
     int max_line = (parent == stdscr) ? LINE_MAX : getmaxy(parent);
     PAIR *tmp;
     bool result = FALSE;

     head_line("Use arrows to move cursor, anything else to mark corner 1");
     if ((tmp = selectcell(parent, 0,
 			  min_line, min_col,
 			  max_line, max_col,
 			  FALSE,
 			  (bool *) 0)) != 0) {
 	*ul = *tmp;
 	MvWAddCh(parent, ul->y, ul->x, '*');

 	head_line("Use arrows to move cursor, anything else to mark corner 2");
 	if ((tmp = selectcell(parent, 0,
 			      ul->y, ul->x,
 			      max_line, max_col,
 			      FALSE,
 			      (bool *) 0)) != 0) {
 	    *lr = *tmp;
 	    MvWAddCh(parent, lr->y, lr->x, '*');
 	    wmove(parent, lr->y, lr->x);
 	    wsyncdown(parent);
 	    wrefresh(parent);
 	    result = (lr->y != ul->y && lr->x != ul->x);
 	}
     }
     head_line("done");
     return result;
 }

 /*
  * Draw a box inside the given window.
  */
 static void
 box_inside(WINDOW *win)
 {
     int y0, x0;
     int y1, x1;

     getyx(win, y0, x0);
     getmaxyx(win, y1, x1);

     MvWHLine(win, 0, 0, ACS_HLINE, x1);
     MvWHLine(win, y1 - 1, 0, ACS_HLINE, x1);

     MvWVLine(win, 0, 0, ACS_VLINE, y1);
     MvWVLine(win, 0, x1 - 1, ACS_VLINE, y1);

     MvWAddCh(win, 0, 0, ACS_ULCORNER);
     MvWAddCh(win, y1 - 1, 0, ACS_LLCORNER);
     MvWAddCh(win, 0, x1 - 1, ACS_URCORNER);
     MvWAddCh(win, y1 - 1, x1 - 1, ACS_LRCORNER);

     wsyncdown(win);
     wmove(win, y0, x0);
     wrefresh(win);
 }

 /*
  * Add a window to our list.
  */
 static void
 add_window(WINDOW *parent, WINDOW *child)
 {
     static unsigned have = 0;
     unsigned need = ((num_windows + 1) | 31) + 1;

     keypad(child, TRUE);
     if (need > have) {
 	all_windows = typeRealloc(FRAME, need, all_windows);
 	if (!all_windows)
 	    failed("add_window");
     }
     all_windows[num_windows].parent = parent;
     all_windows[num_windows].child = child;
     num_windows++;
 }

 static int
 window2num(WINDOW *win)
 {
     int n;
     int result = -1;
     for (n = 0; n < (int) num_windows; ++n) {
 	if (win == all_windows[n].child) {
 	    result = n;
 	    break;
 	}
     }
     return result;
 }

 static WINDOW *
 parent_of(WINDOW *win)
 {
     WINDOW *result = 0;
     int n = window2num(win);
     if (n >= 0)
 	result = all_windows[n].parent;
     return result;
 }

 static void
 repaint_one(WINDOW *win)
 {
     touchwin(win);
     wnoutrefresh(win);
 }

 static void
 refresh_all(WINDOW *win)
 {
     unsigned n;

     for (n = 0; n < num_windows; ++n) {
 	if (all_windows[n].child != win) {
 	    repaint_one(all_windows[n].child);
 	}
     }

     repaint_one(win);
     doupdate();
 }

 static WINDOW *
 next_window(WINDOW *win)
 {
     WINDOW *result = win;
     int n = window2num(win);

     if (n++ >= 0) {
 	result = all_windows[(unsigned) n % num_windows].child;
 	wmove(result, 0, 0);
 	wrefresh(result);
     }
     return result;
 }

 static WINDOW *
 prev_window(WINDOW *win)
 {
     WINDOW *result = win;
     int n = window2num(win);

     if (n-- >= 0) {
 	if (n < 0)
 	    n = (int) (num_windows - 1);
 	result = all_windows[(unsigned) n % num_windows].child;
 	wmove(result, 0, 0);
 	wrefresh(result);
     }
     return result;
 }

 static void
 recur_move_window(WINDOW *parent, int dy, int dx)
 {
     unsigned n;

     for (n = 0; n < num_windows; ++n) {
 	if (all_windows[n].parent == parent) {
 	    mvwin(all_windows[n].child, dy, dx);
 	    recur_move_window(all_windows[n].child, dy, dx);
 	}
     }
 }

 /*
  * test mvwin().
  */
 static bool
 move_window(WINDOW *win, bool recur)
 {
     WINDOW *parent = parent_of(win);
     bool result = FALSE;

     if (parent != 0) {
 	bool top = (parent == stdscr);
 	int min_col = top ? COL_MIN : 0;
 	int max_col = top ? COL_MAX : getmaxx(parent);
 	int min_line = top ? LINE_MIN : 0;
 	int max_line = top ? LINE_MAX : getmaxy(parent);
 	PAIR *tmp;
 	bool more;

 	head_line("Select new position for %swindow", top ? "" : "sub");

 	while ((tmp = selectcell(parent,
 				 win,
 				 min_line, min_col,
 				 max_line, max_col,
 				 FALSE,
 				 &more)) != 0) {
 	    int y0, x0;
 	    getbegyx(parent, y0, x0);
 	    /*
 	     * Moving a subwindow has the effect of moving a viewport around
 	     * the screen.  The parent window retains the contents of the
 	     * subwindow in the original location, but the viewport will show
 	     * the contents (again) at the new location.  So it will look odd
 	     * when testing.
 	     */
 	    if (mvwin(win, y0 + tmp->y, x0 + tmp->x) != ERR) {
 		if (recur) {
 		    recur_move_window(win, tmp->y, tmp->x);
 		}
 		refresh_all(win);
 		doupdate();
 		result = TRUE;
 	    } else {
 		result = FALSE;
 	    }
 	    if (!more)
 		break;
 	}
     }
     head_line("done");
     return result;
 }

 static void
 show_derwin(WINDOW *win)
 {
     int pary, parx, maxy, maxx;

     getmaxyx(win, maxy, maxx);
     getparyx(win, pary, parx);

     head_line("Select new position for derived window at %d,%d (%d,%d)",
 	      pary, parx, maxy, maxx);
 }

 /*
  * test mvderwin().
  */
 static bool
 move_derwin(WINDOW *win)
 {
     WINDOW *parent = parent_of(win);
     bool result = FALSE;

     if (parent != 0) {
 	bool top = (parent == stdscr);
 	int min_col = top ? COL_MIN : 0;
 	int max_col = top ? COL_MAX : getmaxx(parent);
 	int min_line = top ? LINE_MIN : 0;
 	int max_line = top ? LINE_MAX : getmaxy(parent);
 	PAIR *tmp;
 	bool more;

 	show_derwin(win);
 	while ((tmp = selectcell(parent,
 				 win,
 				 min_line, min_col,
 				 max_line, max_col,
 				 TRUE,
 				 &more)) != 0) {
 	    if (mvderwin(win, tmp->y, tmp->x) != ERR) {
 		refresh_all(win);
 		doupdate();
 		repaint_one(win);
 		doupdate();
 		result = TRUE;
 		show_derwin(win);
 	    } else {
 		flash();
 	    }
 	    if (!more)
 		break;
 	}
     }
     head_line("done");
     return result;
 }

 static void
 fill_window(WINDOW *win, chtype ch)
 {
     int y, x;
     int y0, x0;
     int y1, x1;

     getyx(win, y0, x0);
     getmaxyx(win, y1, x1);
     for (y = 0; y < y1; ++y) {
 	for (x = 0; x < x1; ++x) {
 	    MvWAddCh(win, y, x, ch);
 	}
     }
     wsyncdown(win);
     wmove(win, y0, x0);
     wrefresh(win);
 }

 static void
 fill_with_pattern(WINDOW *win)
 {
     int y, x;
     int y0, x0;
     int y1, x1;
     int ch = 'a';

     getyx(win, y0, x0);
     getmaxyx(win, y1, x1);
     for (y = 0; y < y1; ++y) {
 	for (x = 0; x < x1; ++x) {
 	    MvWAddCh(win, y, x, (chtype) ch);
 	    if (++ch > 'z')
 		ch = 'a';
 	}
     }
     wsyncdown(win);
     wmove(win, y0, x0);
     wrefresh(win);
 }

 #define lines_of(ul,lr)	(lr.y - ul.y + 1)
 #define cols_of(ul,lr)	(lr.x - ul.x + 1)
 #define pair_of(ul)	ul.y, ul.x

 static WINDOW *
 create_my_window(WINDOW *current)
 {
     PAIR ul, lr;
     WINDOW *result = 0;

     if (getwindow(stdscr, &ul, &lr)) {
 	result = newwin(lines_of(ul, lr), cols_of(ul, lr), pair_of(ul));
 	if (result != 0) {
 	    fill_window(result, 'c');
 	    add_window(stdscr, result);
 	}
     }
     if (result == 0)
 	result = current;
     return result;
 }

 static WINDOW *
 create_my_derwin(WINDOW *parent)
 {
     PAIR ul, lr;
     WINDOW *result = 0;

     if (getwindow(parent, &ul, &lr)) {
 	result = derwin(parent, lines_of(ul, lr), cols_of(ul, lr), pair_of(ul));
 	if (result != 0) {
 	    fill_window(result, 'd');
 	    add_window(parent, result);
 	}
     }
     if (result == 0)
 	result = parent;
     return result;
 }

 static WINDOW *
 create_my_subwin(WINDOW *parent)
 {
     PAIR ul, lr;
     WINDOW *result = 0;

     if (getwindow(parent, &ul, &lr)) {
 	result = subwin(parent,
 			lines_of(ul, lr),
 			cols_of(ul, lr),
 			ul.y + getbegy(parent),
 			ul.x + getbegx(parent));
 	if (result != 0) {
 	    fill_window(result, 's');
 	    add_window(parent, result);
 	}
     }
     if (result == 0)
 	result = parent;
     return result;
 }

 static void
 show_help(WINDOW *current)
 {
     /* *INDENT-OFF* */
     static struct {
 	int	key;
 	CONST_FMT char * msg;
     } help[] = {
 	{ '?',		"Show this screen" },
 	{ 'b',		"Draw a box inside the current window" },
 	{ 'c',		"Create a new window" },
 	{ 'd',		"Create a new derived window" },
 	{ 'D',		"Move derived window (moves viewport)" },
 	{ 'f',		"Fill the current window with the next character" },
 	{ 'F',		"Fill the current window with a pattern" },
 	{ 'm',		"Move the current window" },
 	{ 'M',		"Move the current window (and its children)" },
 	{ 'q',		"Quit" },
 	{ 's',		"Create a new subwindow" },
 	{ CTRL('L'),	"Repaint all windows, doing current one last" },
 	{ CTRL('N'),	"Cursor to next window" },
 	{ CTRL('P'),	"Cursor to previous window" },
     };
     /* *INDENT-ON* */

     WINDOW *mywin = newwin(LINES, COLS, 0, 0);
     int row;

     for (row = 0; row < LINES - 2 && row < (int) SIZEOF(help); ++row) {
 	wmove(mywin, row + 1, 1);
 	wprintw(mywin, "%s", keyname(help[row].key));
 	wmove(mywin, row + 1, 20);
 	wprintw(mywin, "%s", help[row].msg);
     }
     box_inside(mywin);
     wmove(mywin, 1, 1);
     wgetch(mywin);
     delwin(mywin);
     refresh_all(current);
 }

 int
 main(int argc GCC_UNUSED, char *argv[]GCC_UNUSED)
 {
     WINDOW *current_win;
     int ch;
     bool done = FALSE;

     initscr();
     cbreak();
     noecho();
     nonl();
     intrflush(stdscr, FALSE);

     add_window(0, current_win = stdscr);

 #ifdef NCURSES_MOUSE_VERSION
     (void) mousemask(BUTTON1_CLICKED, (mmask_t *) NULL);
 #endif /* NCURSES_MOUSE_VERSION */

     while (!done && (ch = wgetch(current_win)) != ERR) {
 	int y, x;

 	getyx(current_win, y, x);

 	switch (ch) {
 	case '?':
 	    show_help(current_win);
 	    break;
 	case 'b':
 	    box_inside(current_win);
 	    break;
 	case 'c':
 	    current_win = create_my_window(current_win);
 	    break;
 	case 'd':
 	    current_win = create_my_derwin(current_win);
 	    break;
 	case 'D':
 	    if (!move_derwin(current_win)) {
 		tail_line("error");
 		continue;
 	    }
 	    break;
 	case 'f':
 	    fill_window(current_win, (chtype) wgetch(current_win));
 	    break;
 	case 'F':
 	    fill_with_pattern(current_win);
 	    break;
 	case 'm':
 	case 'M':
 	    if (!move_window(current_win, (ch == 'M'))) {
 		tail_line("error");
 		continue;
 	    }
 	    break;
 	case 'q':
 	    done = TRUE;
 	    break;
 	case 's':
 	    current_win = create_my_subwin(current_win);
 	    break;
 	case CTRL('L'):
 	    refresh_all(current_win);
 	    break;
 	case CTRL('N'):
 	    current_win = next_window(current_win);
 	    break;
 	case CTRL('P'):
 	    current_win = prev_window(current_win);
 	    break;
 #if 0
 	    /* want to allow cursor to move around the current window too */
 	    /* want to test the resizing of windows and subwindows too */
 	    /* want to allow deleting a window also */
 #endif
 	default:
 	    wmove(current_win, y, x);
 	    tail_line("unrecognized key (use '?' for help)");
 	    beep();
 	    continue;
 	}
 	tail_line("size [%d,%d] begin [%d,%d] parent [%d,%d]",
 		  getmaxy(current_win),
 		  getmaxx(current_win),
 		  getbegy(current_win),
 		  getbegx(current_win),
 		  getpary(current_win),
 		  getparx(current_win));
 	wmove(current_win, 0, 0);
     }
     endwin();
     ExitProgram(EXIT_SUCCESS);
 }
	/****************************************************************************
	* Copyright (c) 2006-2012,2013 Free Software Foundation, Inc. *
	* *
	* 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: *
	* *
	* The above copyright notice and this permission notice shall be included *
	* in all copies or substantial portions of the Software. *
	* *
	* 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. *
	* *
	* 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. *
	****************************************************************************/
	/*
	* $Id: movewindow.c,v 1.39 2013/05/04 19:41:02 tom Exp $
	*
	* Demonstrate move functions for windows and derived windows from the curses
	* library.
	*
	* Author: Thomas E. Dickey
	*/
	/*
	derwin
	mvderwin
	subwin
	mvwin

	TODO:
	add command to reset subwindow's origin to coincide with parent.
	add command to delete subwindow (check if it has subwindows though)
	*/

	#include <test.priv.h>
	#include <stdarg.h>

	#ifdef HAVE_XCURSES
	#undef derwin
	#endif

	#ifdef NCURSES_VERSION
	#define CONST_FMT const
	#else
	#define CONST_FMT /* nothing */
	#endif

	#undef LINE_MAX

	#define LINE_MIN 2
	#define LINE_MAX (LINES - 2)
	#define COL_MIN 2
	#define COL_MAX (COLS - 2)

	typedef struct {
	int y, x;
	} PAIR;

	typedef struct {
	WINDOW parent; / need this since WINDOW->_parent is not portable */
	WINDOW child; / the actual value */
	} FRAME;

	static void head_line(CONST_FMT char *fmt,...) GCC_PRINTFLIKE(1, 2);
	static void tail_line(CONST_FMT char *fmt,...) GCC_PRINTFLIKE(1, 2);

	static unsigned num_windows;
	static FRAME *all_windows;

	static void
	failed(const char *s)
	{
	perror(s);
	endwin();
	ExitProgram(EXIT_FAILURE);
	}

	static void
	message(int lineno, CONST_FMT char *fmt, va_list argp)
	{
	int y, x;

	getyx(stdscr, y, x);
	move(lineno, 0);
	clrtoeol();

	#ifdef HAVE_XCURSES
	{
	char buffer[1024];
	vsprintf(buffer, fmt, argp);
	addstr(buffer);
	}
	#else
	vwprintw(stdscr, fmt, argp);
	#endif

	move(y, x);
	refresh();
	}

	static void
	head_line(CONST_FMT char *fmt,...)
	{
	va_list argp;

	va_start(argp, fmt);
	message(0, fmt, argp);
	va_end(argp);
	}

	static void
	tail_line(CONST_FMT char *fmt,...)
	{
	va_list argp;

	va_start(argp, fmt);
	message(LINES - 1, fmt, argp);
	va_end(argp);
	}

	/*
	* Arrow keys move cursor, return location at current on non-arrow key.
	*/
	static PAIR *
	selectcell(WINDOW *parent,
	WINDOW *child,
	int uli, int ulj,
	int lri, int lrj,
	bool relative,
	bool * more)
	{
	static PAIR res; /* result cell */
	int si = lri - uli + 1; /* depth of the select area */
	int sj = lrj - ulj + 1; /* width of the select area */
	int i = 0, j = 0; /* offsets into the select area */

	res.y = uli;
	res.x = ulj;

	if (child != 0) {
	if (relative) {
	getparyx(child, i, j);
	} else {
	getbegyx(child, i, j);
	i -= uli + getbegy(parent);
	j -= ulj + getbegx(parent);
	}
	}

	if (more)
	*more = FALSE;

	for (;;) {
	bool moved = FALSE;

	tail_line("Upper left [%2d,%2d] Lower right [%2d,%2d] -> %d,%d -> %d,%d",
	uli, ulj,
	lri, lrj,
	i, j,
	uli + i, ulj + j);
	wmove(parent, uli + i, ulj + j);

	switch (wgetch(parent)) {
	case KEY_UP:
	i += si - 1;
	moved = TRUE;
	break;
	case KEY_DOWN:
	i++;
	moved = TRUE;
	break;
	case KEY_LEFT:
	j += sj - 1;
	moved = TRUE;
	break;
	case KEY_RIGHT:
	j++;
	moved = TRUE;
	break;
	case QUIT:
	case ESCAPE:
	return ((PAIR *) 0);
	#ifdef NCURSES_MOUSE_VERSION
	case KEY_MOUSE:
	{
	MEVENT event;

	getmouse(&event);
	if (event.y > uli && event.x > ulj) {
	if (parent != stdscr) {
	i = event.y - getbegy(parent) - uli;
	j = event.x - getbegx(parent) - ulj;
	} else {
	i = event.y - uli;
	j = event.x - ulj;
	}
	} else {
	beep();
	break;
	}
	}
	/* FALLTHRU */
	#endif
	default:
	res.y = uli + i;
	res.x = ulj + j;
	return (&res);
	}

	if (si <= 0)
	i = 0;
	else
	i %= si;

	if (sj <= 0)
	j = 0;
	else
	j %= sj;

	/*
	* If the caller can handle continuous movement, return the result.
	*/
	if (moved && more) {
	*more = TRUE;
	res.y = uli + i;
	res.x = ulj + j;
	return (&res);
	}
	}
	}

	/*
	* Ask user for a window definition.
	*/
	static bool
	getwindow(WINDOW parent, PAIR ul, PAIR * lr)
	{
	int min_col = (parent == stdscr) ? COL_MIN : 0;
	int max_col = (parent == stdscr) ? COL_MAX : getmaxx(parent);
	int min_line = (parent == stdscr) ? LINE_MIN : 0;
	int max_line = (parent == stdscr) ? LINE_MAX : getmaxy(parent);
	PAIR *tmp;
	bool result = FALSE;

	head_line("Use arrows to move cursor, anything else to mark corner 1");
	if ((tmp = selectcell(parent, 0,
	min_line, min_col,
	max_line, max_col,
	FALSE,
	(bool *) 0)) != 0) {
	ul = tmp;
	MvWAddCh(parent, ul->y, ul->x, '*');

	head_line("Use arrows to move cursor, anything else to mark corner 2");
	if ((tmp = selectcell(parent, 0,
	ul->y, ul->x,
	max_line, max_col,
	FALSE,
	(bool *) 0)) != 0) {
	lr = tmp;
	MvWAddCh(parent, lr->y, lr->x, '*');
	wmove(parent, lr->y, lr->x);
	wsyncdown(parent);
	wrefresh(parent);
	result = (lr->y != ul->y && lr->x != ul->x);
	}
	}
	head_line("done");
	return result;
	}

	/*
	* Draw a box inside the given window.
	*/
	static void
	box_inside(WINDOW *win)
	{
	int y0, x0;
	int y1, x1;

	getyx(win, y0, x0);
	getmaxyx(win, y1, x1);

	MvWHLine(win, 0, 0, ACS_HLINE, x1);
	MvWHLine(win, y1 - 1, 0, ACS_HLINE, x1);

	MvWVLine(win, 0, 0, ACS_VLINE, y1);
	MvWVLine(win, 0, x1 - 1, ACS_VLINE, y1);

	MvWAddCh(win, 0, 0, ACS_ULCORNER);
	MvWAddCh(win, y1 - 1, 0, ACS_LLCORNER);
	MvWAddCh(win, 0, x1 - 1, ACS_URCORNER);
	MvWAddCh(win, y1 - 1, x1 - 1, ACS_LRCORNER);

	wsyncdown(win);
	wmove(win, y0, x0);
	wrefresh(win);
	}

	/*
	* Add a window to our list.
	*/
	static void
	add_window(WINDOW parent, WINDOW child)
	{
	static unsigned have = 0;
	unsigned need = ((num_windows + 1) \| 31) + 1;

	keypad(child, TRUE);
	if (need > have) {
	all_windows = typeRealloc(FRAME, need, all_windows);
	if (!all_windows)
	failed("add_window");
	}
	all_windows[num_windows].parent = parent;
	all_windows[num_windows].child = child;
	num_windows++;
	}

	static int
	window2num(WINDOW *win)
	{
	int n;
	int result = -1;
	for (n = 0; n < (int) num_windows; ++n) {
	if (win == all_windows[n].child) {
	result = n;
	break;
	}
	}
	return result;
	}

	static WINDOW *
	parent_of(WINDOW *win)
	{
	WINDOW *result = 0;
	int n = window2num(win);
	if (n >= 0)
	result = all_windows[n].parent;
	return result;
	}

	static void
	repaint_one(WINDOW *win)
	{
	touchwin(win);
	wnoutrefresh(win);
	}

	static void
	refresh_all(WINDOW *win)
	{
	unsigned n;

	for (n = 0; n < num_windows; ++n) {
	if (all_windows[n].child != win) {
	repaint_one(all_windows[n].child);
	}
	}

	repaint_one(win);
	doupdate();
	}

	static WINDOW *
	next_window(WINDOW *win)
	{
	WINDOW *result = win;
	int n = window2num(win);

	if (n++ >= 0) {
	result = all_windows[(unsigned) n % num_windows].child;
	wmove(result, 0, 0);
	wrefresh(result);
	}
	return result;
	}

	static WINDOW *
	prev_window(WINDOW *win)
	{
	WINDOW *result = win;
	int n = window2num(win);

	if (n-- >= 0) {
	if (n < 0)
	n = (int) (num_windows - 1);
	result = all_windows[(unsigned) n % num_windows].child;
	wmove(result, 0, 0);
	wrefresh(result);
	}
	return result;
	}

	static void
	recur_move_window(WINDOW *parent, int dy, int dx)
	{
	unsigned n;

	for (n = 0; n < num_windows; ++n) {
	if (all_windows[n].parent == parent) {
	mvwin(all_windows[n].child, dy, dx);
	recur_move_window(all_windows[n].child, dy, dx);
	}
	}
	}

	/*
	* test mvwin().
	*/
	static bool
	move_window(WINDOW *win, bool recur)
	{
	WINDOW *parent = parent_of(win);
	bool result = FALSE;

	if (parent != 0) {
	bool top = (parent == stdscr);
	int min_col = top ? COL_MIN : 0;
	int max_col = top ? COL_MAX : getmaxx(parent);
	int min_line = top ? LINE_MIN : 0;
	int max_line = top ? LINE_MAX : getmaxy(parent);
	PAIR *tmp;
	bool more;

	head_line("Select new position for %swindow", top ? "" : "sub");

	while ((tmp = selectcell(parent,
	win,
	min_line, min_col,
	max_line, max_col,
	FALSE,
	&more)) != 0) {
	int y0, x0;
	getbegyx(parent, y0, x0);
	/*
	* Moving a subwindow has the effect of moving a viewport around
	* the screen. The parent window retains the contents of the
	* subwindow in the original location, but the viewport will show
	* the contents (again) at the new location. So it will look odd
	* when testing.
	*/
	if (mvwin(win, y0 + tmp->y, x0 + tmp->x) != ERR) {
	if (recur) {
	recur_move_window(win, tmp->y, tmp->x);
	}
	refresh_all(win);
	doupdate();
	result = TRUE;
	} else {
	result = FALSE;
	}
	if (!more)
	break;
	}
	}
	head_line("done");
	return result;
	}

	static void
	show_derwin(WINDOW *win)
	{
	int pary, parx, maxy, maxx;

	getmaxyx(win, maxy, maxx);
	getparyx(win, pary, parx);

	head_line("Select new position for derived window at %d,%d (%d,%d)",
	pary, parx, maxy, maxx);
	}

	/*
	* test mvderwin().
	*/
	static bool
	move_derwin(WINDOW *win)
	{
	WINDOW *parent = parent_of(win);
	bool result = FALSE;

	if (parent != 0) {
	bool top = (parent == stdscr);
	int min_col = top ? COL_MIN : 0;
	int max_col = top ? COL_MAX : getmaxx(parent);
	int min_line = top ? LINE_MIN : 0;
	int max_line = top ? LINE_MAX : getmaxy(parent);
	PAIR *tmp;
	bool more;

	show_derwin(win);
	while ((tmp = selectcell(parent,
	win,
	min_line, min_col,
	max_line, max_col,
	TRUE,
	&more)) != 0) {
	if (mvderwin(win, tmp->y, tmp->x) != ERR) {
	refresh_all(win);
	doupdate();
	repaint_one(win);
	doupdate();
	result = TRUE;
	show_derwin(win);
	} else {
	flash();
	}
	if (!more)
	break;
	}
	}
	head_line("done");
	return result;
	}

	static void
	fill_window(WINDOW *win, chtype ch)
	{
	int y, x;
	int y0, x0;
	int y1, x1;

	getyx(win, y0, x0);
	getmaxyx(win, y1, x1);
	for (y = 0; y < y1; ++y) {
	for (x = 0; x < x1; ++x) {
	MvWAddCh(win, y, x, ch);
	}
	}
	wsyncdown(win);
	wmove(win, y0, x0);
	wrefresh(win);
	}

	static void
	fill_with_pattern(WINDOW *win)
	{
	int y, x;
	int y0, x0;
	int y1, x1;
	int ch = 'a';

	getyx(win, y0, x0);
	getmaxyx(win, y1, x1);
	for (y = 0; y < y1; ++y) {
	for (x = 0; x < x1; ++x) {
	MvWAddCh(win, y, x, (chtype) ch);
	if (++ch > 'z')
	ch = 'a';
	}
	}
	wsyncdown(win);
	wmove(win, y0, x0);
	wrefresh(win);
	}

	#define lines_of(ul,lr) (lr.y - ul.y + 1)
	#define cols_of(ul,lr) (lr.x - ul.x + 1)
	#define pair_of(ul) ul.y, ul.x

	static WINDOW *
	create_my_window(WINDOW *current)
	{
	PAIR ul, lr;
	WINDOW *result = 0;

	if (getwindow(stdscr, &ul, &lr)) {
	result = newwin(lines_of(ul, lr), cols_of(ul, lr), pair_of(ul));
	if (result != 0) {
	fill_window(result, 'c');
	add_window(stdscr, result);
	}
	}
	if (result == 0)
	result = current;
	return result;
	}

	static WINDOW *
	create_my_derwin(WINDOW *parent)
	{
	PAIR ul, lr;
	WINDOW *result = 0;

	if (getwindow(parent, &ul, &lr)) {
	result = derwin(parent, lines_of(ul, lr), cols_of(ul, lr), pair_of(ul));
	if (result != 0) {
	fill_window(result, 'd');
	add_window(parent, result);
	}
	}
	if (result == 0)
	result = parent;
	return result;
	}

	static WINDOW *
	create_my_subwin(WINDOW *parent)
	{
	PAIR ul, lr;
	WINDOW *result = 0;

	if (getwindow(parent, &ul, &lr)) {
	result = subwin(parent,
	lines_of(ul, lr),
	cols_of(ul, lr),
	ul.y + getbegy(parent),
	ul.x + getbegx(parent));
	if (result != 0) {
	fill_window(result, 's');
	add_window(parent, result);
	}
	}
	if (result == 0)
	result = parent;
	return result;
	}

	static void
	show_help(WINDOW *current)
	{
	/* INDENT-OFF */
	static struct {
	int key;
	CONST_FMT char * msg;
	} help[] = {
	{ '?', "Show this screen" },
	{ 'b', "Draw a box inside the current window" },
	{ 'c', "Create a new window" },
	{ 'd', "Create a new derived window" },
	{ 'D', "Move derived window (moves viewport)" },
	{ 'f', "Fill the current window with the next character" },
	{ 'F', "Fill the current window with a pattern" },
	{ 'm', "Move the current window" },
	{ 'M', "Move the current window (and its children)" },
	{ 'q', "Quit" },
	{ 's', "Create a new subwindow" },
	{ CTRL('L'), "Repaint all windows, doing current one last" },
	{ CTRL('N'), "Cursor to next window" },
	{ CTRL('P'), "Cursor to previous window" },
	};
	/* INDENT-ON */

	WINDOW *mywin = newwin(LINES, COLS, 0, 0);
	int row;

	for (row = 0; row < LINES - 2 && row < (int) SIZEOF(help); ++row) {
	wmove(mywin, row + 1, 1);
	wprintw(mywin, "%s", keyname(help[row].key));
	wmove(mywin, row + 1, 20);
	wprintw(mywin, "%s", help[row].msg);
	}
	box_inside(mywin);
	wmove(mywin, 1, 1);
	wgetch(mywin);
	delwin(mywin);
	refresh_all(current);
	}

	int
	main(int argc GCC_UNUSED, char *argv[]GCC_UNUSED)
	{
	WINDOW *current_win;
	int ch;
	bool done = FALSE;

	initscr();
	cbreak();
	noecho();
	nonl();
	intrflush(stdscr, FALSE);

	add_window(0, current_win = stdscr);

	#ifdef NCURSES_MOUSE_VERSION
	(void) mousemask(BUTTON1_CLICKED, (mmask_t *) NULL);
	#endif /* NCURSES_MOUSE_VERSION */

	while (!done && (ch = wgetch(current_win)) != ERR) {
	int y, x;

	getyx(current_win, y, x);

	switch (ch) {
	case '?':
	show_help(current_win);
	break;
	case 'b':
	box_inside(current_win);
	break;
	case 'c':
	current_win = create_my_window(current_win);
	break;
	case 'd':
	current_win = create_my_derwin(current_win);
	break;
	case 'D':
	if (!move_derwin(current_win)) {
	tail_line("error");
	continue;
	}
	break;
	case 'f':
	fill_window(current_win, (chtype) wgetch(current_win));
	break;
	case 'F':
	fill_with_pattern(current_win);
	break;
	case 'm':
	case 'M':
	if (!move_window(current_win, (ch == 'M'))) {
	tail_line("error");
	continue;
	}
	break;
	case 'q':
	done = TRUE;
	break;
	case 's':
	current_win = create_my_subwin(current_win);
	break;
	case CTRL('L'):
	refresh_all(current_win);
	break;
	case CTRL('N'):
	current_win = next_window(current_win);
	break;
	case CTRL('P'):
	current_win = prev_window(current_win);
	break;
	#if 0
	/* want to allow cursor to move around the current window too */
	/* want to test the resizing of windows and subwindows too */
	/* want to allow deleting a window also */
	#endif
	default:
	wmove(current_win, y, x);
	tail_line("unrecognized key (use '?' for help)");
	beep();
	continue;
	}
	tail_line("size [%d,%d] begin [%d,%d] parent [%d,%d]",
	getmaxy(current_win),
	getmaxx(current_win),
	getbegy(current_win),
	getbegx(current_win),
	getpary(current_win),
	getparx(current_win));
	wmove(current_win, 0, 0);
	}
	endwin();
	ExitProgram(EXIT_SUCCESS);
	}