xref: /netbsd-src/lib/libcurses/color.c (revision 53b02e147d4ed531c0d2a5ca9b3e8026ba3e99b5)
1 /*	$NetBSD: color.c,v 1.45 2021/12/17 03:50:18 uwe Exp $	*/
2 
3 /*
4  * Copyright (c) 2000 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Julian Coleman.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __RCSID("$NetBSD: color.c,v 1.45 2021/12/17 03:50:18 uwe Exp $");
35 #endif				/* not lint */
36 
37 #include "curses.h"
38 #include "curses_private.h"
39 
40 /* Have we initialised colours? */
41 int	__using_color = 0;
42 
43 /* Default colour number */
44 attr_t	__default_color = 0;
45 
46 /* Default colour pair values - white on black. */
47 struct __pair	__default_pair = {COLOR_WHITE, COLOR_BLACK, 0};
48 
49 /* Default colour values */
50 /* Flags for colours and pairs */
51 #define	__USED		0x01
52 
53 static void
54 __change_pair(short);
55 
56 static int
57 init_color_value(short, short, short, short);
58 
59 /*
60  * has_colors --
61  *	Check if terminal has colours.
62  */
63 bool
64 has_colors(void)
65 {
66 	if (max_colors > 0 && max_pairs > 0 &&
67 	    ((set_a_foreground != NULL && set_a_background != NULL) ||
68 		initialize_pair != NULL || initialize_color != NULL ||
69 		(set_background != NULL && set_foreground != NULL)))
70 		return true;
71 	else
72 		return false;
73 }
74 
75 /*
76  * can_change_color --
77  *	Check if terminal can change colours.
78  */
79 bool
80 can_change_color(void)
81 {
82 	return can_change ? true : false;
83 }
84 
85 /*
86  * start_color --
87  *	Initialise colour support.
88  */
89 int
90 start_color(void)
91 {
92 	int			 i;
93 	attr_t			 temp_nc;
94 	struct __winlist	*wlp;
95 	WINDOW			*win;
96 	int			 y, x;
97 
98 	if (has_colors() == FALSE)
99 		return ERR;
100 
101 	/* Max colours and colour pairs */
102 	if (max_colors == -1)
103 		COLORS = 0;
104 	else {
105 		COLORS = max_colors > MAX_COLORS ? MAX_COLORS : max_colors;
106 		if (max_pairs == -1) {
107 			COLOR_PAIRS = 0;
108 			COLORS = 0;
109 		} else {
110 			COLOR_PAIRS = (max_pairs > MAX_PAIRS - 1 ?
111 			    MAX_PAIRS - 1 : max_pairs);
112 			 /* Use the last colour pair for curses default. */
113 			__default_color = COLOR_PAIR(MAX_PAIRS - 1);
114 		}
115 	}
116 	if (!COLORS)
117 		return ERR;
118 
119 	_cursesi_screen->COLORS = COLORS;
120 	_cursesi_screen->COLOR_PAIRS = COLOR_PAIRS;
121 
122 	/* Reset terminal colour and colour pairs. */
123 	if (orig_colors != NULL)
124 		tputs(orig_colors, 0, __cputchar);
125 	if (orig_pair != NULL) {
126 		tputs(orig_pair, 0, __cputchar);
127 		curscr->wattr &= _cursesi_screen->mask_op;
128 	}
129 
130 	/* Type of colour manipulation - ANSI/TEK/HP/other */
131 	if (set_a_foreground != NULL && set_a_background != NULL)
132 		_cursesi_screen->color_type = COLOR_ANSI;
133 	else if (initialize_pair != NULL)
134 		_cursesi_screen->color_type = COLOR_HP;
135 	else if (initialize_color != NULL)
136 		_cursesi_screen->color_type = COLOR_TEK;
137 	else if (set_foreground != NULL && set_background != NULL)
138 		_cursesi_screen->color_type = COLOR_OTHER;
139 	else
140 		return(ERR);		/* Unsupported colour method */
141 
142 #ifdef DEBUG
143 	__CTRACE(__CTRACE_COLOR, "start_color: COLORS = %d, COLOR_PAIRS = %d",
144 	    COLORS, COLOR_PAIRS);
145 	switch (_cursesi_screen->color_type) {
146 	case COLOR_ANSI:
147 		__CTRACE(__CTRACE_COLOR, " (ANSI style)\n");
148 		break;
149 	case COLOR_HP:
150 		__CTRACE(__CTRACE_COLOR, " (HP style)\n");
151 		break;
152 	case COLOR_TEK:
153 		__CTRACE(__CTRACE_COLOR, " (Tektronics style)\n");
154 		break;
155 	case COLOR_OTHER:
156 		__CTRACE(__CTRACE_COLOR, " (Other style)\n");
157 		break;
158 	}
159 #endif
160 
161 	/*
162 	 * Attributes that cannot be used with color.
163 	 * Store these in an attr_t for wattrset()/wattron().
164 	 */
165 	_cursesi_screen->nca = __NORMAL;
166 	if (no_color_video != -1) {
167 		temp_nc = (attr_t)t_no_color_video(_cursesi_screen->term);
168 		if (temp_nc & 0x0001)
169 			_cursesi_screen->nca |= __STANDOUT;
170 		if (temp_nc & 0x0002)
171 			_cursesi_screen->nca |= __UNDERSCORE;
172 		if (temp_nc & 0x0004)
173 			_cursesi_screen->nca |= __REVERSE;
174 		if (temp_nc & 0x0008)
175 			_cursesi_screen->nca |= __BLINK;
176 		if (temp_nc & 0x0010)
177 			_cursesi_screen->nca |= __DIM;
178 		if (temp_nc & 0x0020)
179 			_cursesi_screen->nca |= __BOLD;
180 		if (temp_nc & 0x0040)
181 			_cursesi_screen->nca |= __BLANK;
182 		if (temp_nc & 0x0080)
183 			_cursesi_screen->nca |= __PROTECT;
184 		if (temp_nc & 0x0100)
185 			_cursesi_screen->nca |= __ALTCHARSET;
186 	}
187 	__CTRACE(__CTRACE_COLOR, "start_color: _cursesi_screen->nca = %08x\n",
188 	    _cursesi_screen->nca);
189 
190 	/* Set up initial 8 colours */
191 #define	RGB_ON	680	/* Allow for bright colours */
192 	if (COLORS >= COLOR_BLACK)
193 		(void)init_color_value(COLOR_BLACK, 0, 0, 0);
194 	if (COLORS >= COLOR_RED)
195 		(void)init_color_value(COLOR_RED, RGB_ON, 0, 0);
196 	if (COLORS >= COLOR_GREEN)
197 		(void)init_color_value(COLOR_GREEN, 0, RGB_ON, 0);
198 	if (COLORS >= COLOR_YELLOW)
199 		(void)init_color_value(COLOR_YELLOW, RGB_ON, RGB_ON, 0);
200 	if (COLORS >= COLOR_BLUE)
201 		(void)init_color_value(COLOR_BLUE, 0, 0, RGB_ON);
202 	if (COLORS >= COLOR_MAGENTA)
203 		(void)init_color_value(COLOR_MAGENTA, RGB_ON, 0, RGB_ON);
204 	if (COLORS >= COLOR_CYAN)
205 		(void)init_color_value(COLOR_CYAN, 0, RGB_ON, RGB_ON);
206 	if (COLORS >= COLOR_WHITE)
207 		(void)init_color_value(COLOR_WHITE, RGB_ON, RGB_ON, RGB_ON);
208 
209 	/* Initialise other colours */
210 	for (i = 8; i < COLORS; i++) {
211 		_cursesi_screen->colours[i].red = 0;
212 		_cursesi_screen->colours[i].green = 0;
213 		_cursesi_screen->colours[i].blue = 0;
214 		_cursesi_screen->colours[i].flags = 0;
215 	}
216 
217 	/* Initialise pair 0 to default colours. */
218 	_cursesi_screen->colour_pairs[0].fore = -1;
219 	_cursesi_screen->colour_pairs[0].back = -1;
220 	_cursesi_screen->colour_pairs[0].flags = 0;
221 
222 	/* Initialise user colour pairs to default (white on black) */
223 	for (i = 0; i < COLOR_PAIRS; i++) {
224 		_cursesi_screen->colour_pairs[i].fore = COLOR_WHITE;
225 		_cursesi_screen->colour_pairs[i].back = COLOR_BLACK;
226 		_cursesi_screen->colour_pairs[i].flags = 0;
227 	}
228 
229 	/* Initialise default colour pair. */
230 	_cursesi_screen->colour_pairs[PAIR_NUMBER(__default_color)].fore =
231 	    __default_pair.fore;
232 	_cursesi_screen->colour_pairs[PAIR_NUMBER(__default_color)].back =
233 	    __default_pair.back;
234 	_cursesi_screen->colour_pairs[PAIR_NUMBER(__default_color)].flags =
235 	    __default_pair.flags;
236 
237 	__using_color = 1;
238 
239 	/* Set all positions on all windows to curses default colours. */
240 	for (wlp = _cursesi_screen->winlistp; wlp != NULL; wlp = wlp->nextp) {
241 		win = wlp->winp;
242 		if (wlp->winp != __virtscr && wlp->winp != curscr) {
243 			/* Set color attribute on other windows */
244 			win->battr |= __default_color;
245 			for (y = 0; y < win->maxy; y++) {
246 				for (x = 0; x < win->maxx; x++) {
247 					win->alines[y]->line[x].attr &= ~__COLOR;
248 					win->alines[y]->line[x].attr |= __default_color;
249 				}
250 			}
251 			__touchwin(win);
252 		}
253 	}
254 
255 	return(OK);
256 }
257 
258 /*
259  * init_pair --
260  *	Set pair foreground and background colors.
261  *	Our default colour ordering is ANSI - 1 = red, 4 = blue, 3 = yellow,
262  *	6 = cyan.  The older style (Sb/Sf) uses 1 = blue, 4 = red, 3 = cyan,
263  *	6 = yellow, so we swap them here and in pair_content().
264  */
265 int
266 init_pair(short pair, short fore, short back)
267 {
268 	int	changed;
269 
270 	__CTRACE(__CTRACE_COLOR, "init_pair: %d, %d, %d\n", pair, fore, back);
271 
272 	if (pair < 0 || pair >= COLOR_PAIRS)
273 		return ERR;
274 
275 	if (pair == 0) /* Ignore request for pair 0, it is default. */
276 		return OK;
277 
278 	if (fore >= COLORS)
279 		return ERR;
280 	if (back >= COLORS)
281 		return ERR;
282 
283 	/* Swap red/blue and yellow/cyan */
284 	if (_cursesi_screen->color_type == COLOR_OTHER) {
285 		switch (fore) {
286 		case COLOR_RED:
287 			fore = COLOR_BLUE;
288 			break;
289 		case COLOR_BLUE:
290 			fore = COLOR_RED;
291 			break;
292 		case COLOR_YELLOW:
293 			fore = COLOR_CYAN;
294 			break;
295 		case COLOR_CYAN:
296 			fore = COLOR_YELLOW;
297 			break;
298 		}
299 		switch (back) {
300 		case COLOR_RED:
301 			back = COLOR_BLUE;
302 			break;
303 		case COLOR_BLUE:
304 			back = COLOR_RED;
305 			break;
306 		case COLOR_YELLOW:
307 			back = COLOR_CYAN;
308 			break;
309 		case COLOR_CYAN:
310 			back = COLOR_YELLOW;
311 			break;
312 		}
313 	}
314 
315 	if ((_cursesi_screen->colour_pairs[pair].flags & __USED) &&
316 	    (fore != _cursesi_screen->colour_pairs[pair].fore ||
317 	     back != _cursesi_screen->colour_pairs[pair].back))
318 		changed = 1;
319 	else
320 		changed = 0;
321 
322 	_cursesi_screen->colour_pairs[pair].flags |= __USED;
323 	_cursesi_screen->colour_pairs[pair].fore = fore;
324 	_cursesi_screen->colour_pairs[pair].back = back;
325 
326 	/* XXX: need to initialise HP style (Ip) */
327 
328 	if (changed)
329 		__change_pair(pair);
330 	return OK;
331 }
332 
333 /*
334  * pair_content --
335  *	Get pair foreground and background colours.
336  */
337 int
338 pair_content(short pair, short *forep, short *backp)
339 {
340 	if (pair < 0 || pair > _cursesi_screen->COLOR_PAIRS)
341 		return ERR;
342 
343 	*forep = _cursesi_screen->colour_pairs[pair].fore;
344 	*backp = _cursesi_screen->colour_pairs[pair].back;
345 
346 	/* Swap red/blue and yellow/cyan */
347 	if (_cursesi_screen->color_type == COLOR_OTHER) {
348 		switch (*forep) {
349 		case COLOR_RED:
350 			*forep = COLOR_BLUE;
351 			break;
352 		case COLOR_BLUE:
353 			*forep = COLOR_RED;
354 			break;
355 		case COLOR_YELLOW:
356 			*forep = COLOR_CYAN;
357 			break;
358 		case COLOR_CYAN:
359 			*forep = COLOR_YELLOW;
360 			break;
361 		}
362 		switch (*backp) {
363 		case COLOR_RED:
364 			*backp = COLOR_BLUE;
365 			break;
366 		case COLOR_BLUE:
367 			*backp = COLOR_RED;
368 			break;
369 		case COLOR_YELLOW:
370 			*backp = COLOR_CYAN;
371 			break;
372 		case COLOR_CYAN:
373 			*backp = COLOR_YELLOW;
374 			break;
375 		}
376 	}
377 	return OK;
378 }
379 
380 /*
381  * init_color_Value --
382  *	Set colour red, green and blue values.
383  */
384 static int
385 init_color_value(short color, short red, short green, short blue)
386 {
387 	if (color < 0 || color >= _cursesi_screen->COLORS)
388 		return ERR;
389 
390 	_cursesi_screen->colours[color].red = red;
391 	_cursesi_screen->colours[color].green = green;
392 	_cursesi_screen->colours[color].blue = blue;
393 	return OK;
394 }
395 
396 /*
397  * init_color --
398  *	Set colour red, green and blue values.
399  *	Change color on screen.
400  */
401 int
402 init_color(short color, short red, short green, short blue)
403 {
404 	__CTRACE(__CTRACE_COLOR, "init_color: %d, %d, %d, %d\n",
405 	    color, red, green, blue);
406 	if (init_color_value(color, red, green, blue) == ERR)
407 		return ERR;
408 	if (!can_change || t_initialize_color(_cursesi_screen->term) == NULL)
409 		return ERR;
410 	tputs(tiparm(t_initialize_color(_cursesi_screen->term),
411 	             color, red, green, blue), 0, __cputchar);
412 	return OK;
413 }
414 
415 /*
416  * color_content --
417  *	Get colour red, green and blue values.
418  */
419 int
420 color_content(short color, short *redp, short *greenp, short *bluep)
421 {
422 	if (color < 0 || color >= _cursesi_screen->COLORS)
423 		return ERR;
424 
425 	*redp = _cursesi_screen->colours[color].red;
426 	*greenp = _cursesi_screen->colours[color].green;
427 	*bluep = _cursesi_screen->colours[color].blue;
428 	return OK;
429 }
430 
431 /*
432  * use_default_colors --
433  *	Use terminal default colours instead of curses default colour.
434   */
435 int
436 use_default_colors(void)
437 {
438 	__CTRACE(__CTRACE_COLOR, "use_default_colors\n");
439 
440 	return (assume_default_colors(-1, -1));
441 }
442 
443 /*
444  * assume_default_colors --
445  *	Set the default foreground and background colours.
446  */
447 int
448 assume_default_colors(short fore, short back)
449 {
450 	__CTRACE(__CTRACE_COLOR, "assume_default_colors: %d, %d\n",
451 	    fore, back);
452 	__CTRACE(__CTRACE_COLOR,
453 	    "assume_default_colors: default_colour = %d, pair_number = %d\n",
454 	    __default_color, PAIR_NUMBER(__default_color));
455 
456 	/* Swap red/blue and yellow/cyan */
457 	if (_cursesi_screen->color_type == COLOR_OTHER) {
458 		switch (fore) {
459 		case COLOR_RED:
460 			fore = COLOR_BLUE;
461 			break;
462 		case COLOR_BLUE:
463 			fore = COLOR_RED;
464 			break;
465 		case COLOR_YELLOW:
466 			fore = COLOR_CYAN;
467 			break;
468 		case COLOR_CYAN:
469 			fore = COLOR_YELLOW;
470 			break;
471 		}
472 		switch (back) {
473 		case COLOR_RED:
474 			back = COLOR_BLUE;
475 			break;
476 		case COLOR_BLUE:
477 			back = COLOR_RED;
478 			break;
479 		case COLOR_YELLOW:
480 			back = COLOR_CYAN;
481 			break;
482 		case COLOR_CYAN:
483 			back = COLOR_YELLOW;
484 			break;
485 		}
486 	}
487 	__default_pair.fore = fore;
488 	__default_pair.back = back;
489 	__default_pair.flags = __USED;
490 
491 	if (COLOR_PAIRS) {
492 		_cursesi_screen->colour_pairs[PAIR_NUMBER(__default_color)].fore = fore;
493 		_cursesi_screen->colour_pairs[PAIR_NUMBER(__default_color)].back = back;
494 		_cursesi_screen->colour_pairs[PAIR_NUMBER(__default_color)].flags = __USED;
495 	}
496 
497 	/*
498 	 * If we've already called start_color(), make sure all instances
499 	 * of the curses default colour pair are dirty.
500 	 */
501 	if (__using_color)
502 		__change_pair(PAIR_NUMBER(__default_color));
503 
504 	return(OK);
505 }
506 
507 /* no_color_video is a terminfo macro, but we need to retain binary compat */
508 #ifdef __strong_alias
509 #undef no_color_video
510 __strong_alias(no_color_video, no_color_attributes)
511 #endif
512 /*
513  * no_color_attributes --
514  *	Return attributes that cannot be combined with color.
515  */
516 attr_t
517 no_color_attributes(void)
518 {
519 	return(_cursesi_screen->nca);
520 }
521 
522 /*
523  * __set_color --
524  *	Set terminal foreground and background colours.
525  */
526 void
527 __set_color( /*ARGSUSED*/ WINDOW *win, attr_t attr)
528 {
529 	short	pair;
530 
531 	if ((curscr->wattr & __COLOR) == (attr & __COLOR))
532 		return;
533 
534 	pair = PAIR_NUMBER((uint32_t)attr);
535 	__CTRACE(__CTRACE_COLOR, "__set_color: %d, %d, %d\n", pair,
536 	    _cursesi_screen->colour_pairs[pair].fore,
537 	    _cursesi_screen->colour_pairs[pair].back);
538 	switch (_cursesi_screen->color_type) {
539 	/* Set ANSI foreground and background colours */
540 	case COLOR_ANSI:
541 		if (_cursesi_screen->colour_pairs[pair].fore < 0 ||
542 		    _cursesi_screen->colour_pairs[pair].back < 0)
543 			__unset_color(curscr);
544 		if (_cursesi_screen->colour_pairs[pair].fore >= 0)
545 			tputs(tiparm(t_set_a_foreground(_cursesi_screen->term),
546 			    (int)_cursesi_screen->colour_pairs[pair].fore),
547 			    0, __cputchar);
548 		if (_cursesi_screen->colour_pairs[pair].back >= 0)
549 			tputs(tiparm(t_set_a_background(_cursesi_screen->term),
550 			    (int)_cursesi_screen->colour_pairs[pair].back),
551 			    0, __cputchar);
552 		break;
553 	case COLOR_HP:
554 		/* XXX: need to support HP style */
555 		break;
556 	case COLOR_TEK:
557 		/* XXX: need to support Tek style */
558 		break;
559 	case COLOR_OTHER:
560 		if (_cursesi_screen->colour_pairs[pair].fore < 0 ||
561 		    _cursesi_screen->colour_pairs[pair].back < 0)
562 			__unset_color(curscr);
563 		if (_cursesi_screen->colour_pairs[pair].fore >= 0)
564 			tputs(tiparm(t_set_foreground(_cursesi_screen->term),
565 			    (int)_cursesi_screen->colour_pairs[pair].fore),
566 			    0, __cputchar);
567 		if (_cursesi_screen->colour_pairs[pair].back >= 0)
568 			tputs(tiparm(t_set_background(_cursesi_screen->term),
569 			    (int)_cursesi_screen->colour_pairs[pair].back),
570 			    0, __cputchar);
571 		break;
572 	}
573 	curscr->wattr &= ~__COLOR;
574 	curscr->wattr |= attr & __COLOR;
575 }
576 
577 /*
578  * __unset_color --
579  *	Clear terminal foreground and background colours.
580  */
581 void
582 __unset_color(WINDOW *win)
583 {
584 	__CTRACE(__CTRACE_COLOR, "__unset_color\n");
585 	switch (_cursesi_screen->color_type) {
586 	/* Clear ANSI foreground and background colours */
587 	case COLOR_ANSI:
588 		if (orig_pair != NULL) {
589 			tputs(orig_pair, 0, __cputchar);
590 			win->wattr &= __mask_op;
591 		}
592 		break;
593 	case COLOR_HP:
594 		/* XXX: need to support HP style */
595 		break;
596 	case COLOR_TEK:
597 		/* XXX: need to support Tek style */
598 		break;
599 	case COLOR_OTHER:
600 		if (orig_pair != NULL) {
601 			tputs(orig_pair, 0, __cputchar);
602 			win->wattr &= __mask_op;
603 		}
604 		break;
605 	}
606 }
607 
608 /*
609  * __restore_colors --
610  *	Redo color definitions after restarting 'curses' mode.
611  */
612 void
613 __restore_colors(void)
614 {
615 	if (can_change != 0)
616 		switch (_cursesi_screen->color_type) {
617 		case COLOR_HP:
618 			/* XXX: need to re-initialise HP style (Ip) */
619 			break;
620 		case COLOR_TEK:
621 			/* XXX: need to re-initialise Tek style (Ic) */
622 			break;
623 		}
624 }
625 
626 /*
627  * __change_pair --
628  *	Mark dirty all positions using pair.
629  */
630 void
631 __change_pair(short pair)
632 {
633 	struct __winlist	*wlp;
634 	WINDOW			*win;
635 	int			 y, x;
636 	__LINE			*lp;
637 	uint32_t		cl = COLOR_PAIR(pair);
638 
639 
640 	for (wlp = _cursesi_screen->winlistp; wlp != NULL; wlp = wlp->nextp) {
641 		__CTRACE(__CTRACE_COLOR, "__change_pair: win = %p\n",
642 		    wlp->winp);
643 		win = wlp->winp;
644 		if (win == __virtscr)
645 			continue;
646 		else if (win == curscr) {
647 			/* Reset colour attribute on curscr */
648 			__CTRACE(__CTRACE_COLOR,
649 			    "__change_pair: win == curscr\n");
650 			for (y = 0; y < curscr->maxy; y++) {
651 				lp = curscr->alines[y];
652 				for (x = 0; x < curscr->maxx; x++) {
653 					if ((lp->line[x].attr & __COLOR) == cl)
654 						lp->line[x].attr &= ~__COLOR;
655 				}
656 			}
657 		} else {
658 			/* Mark dirty those positions with colour pair "pair" */
659 			for (y = 0; y < win->maxy; y++) {
660 				lp = win->alines[y];
661 				for (x = 0; x < win->maxx; x++)
662 					if ((lp->line[x].attr &
663 					    __COLOR) == cl) {
664 						if (!(lp->flags & __ISDIRTY))
665 							lp->flags |= __ISDIRTY;
666 						/*
667 						 * firstchp/lastchp are shared
668 						 * between parent window and
669 						 * sub-window.
670 						 */
671 						if (*lp->firstchp > x)
672 							*lp->firstchp = x;
673 						if (*lp->lastchp < x)
674 							*lp->lastchp = x;
675 					}
676 #ifdef DEBUG
677 				if ((win->alines[y]->flags & __ISDIRTY))
678 					__CTRACE(__CTRACE_COLOR,
679 					    "__change_pair: first = %d, "
680 					    "last = %d\n",
681 					    *win->alines[y]->firstchp,
682 					    *win->alines[y]->lastchp);
683 #endif
684 			}
685 		}
686 	}
687 }
688