1 /* xscreensaver, Copyright (c) 1993, 1994, 1995, 1996, 1997
2 * by Jamie Zawinski <jwz@netscape.com>
4 * Permission to use, copy, modify, distribute, and sell this software and its
5 * documentation for any purpose is hereby granted without fee, provided that
6 * the above copyright notice appear in all copies and that both that
7 * copyright notice and this permission notice appear in supporting
8 * documentation. No representations are made about the suitability of this
9 * software for any purpose. It is provided "as is" without express or
13 /* This file contains some code for intelligently picking the best visual
14 (where "best" is biased in the direction of either: high color counts;
15 or: having writable color cells...)
19 #include "resources.h" /* for get_string_resource() */
22 #include <X11/Xutil.h>
24 extern char *progname;
28 # define isupper(c) ((c) >= 'A' && (c) <= 'Z')
31 # define _tolower(c) ((c) - 'A' + 'a')
35 static Visual *pick_best_visual (Screen *, Bool, Bool);
36 static Visual *pick_mono_visual (Screen *);
37 static Visual *pick_best_visual_of_class (Screen *, int);
38 static Visual *id_to_visual (Screen *, int);
39 static Visual *id_to_visual (Screen *screen, int id);
42 #define DEFAULT_VISUAL -1
43 #define BEST_VISUAL -2
44 #define MONO_VISUAL -3
45 #define GRAY_VISUAL -4
46 #define COLOR_VISUAL -5
47 #define SPECIFIC_VISUAL -6
50 get_visual (Screen *screen, const char *string, Bool prefer_writable_cells,
53 char *v = (string ? strdup(string) : 0);
60 for (tmp = v; *tmp; tmp++)
61 if (isupper (*tmp)) *tmp = _tolower (*tmp);
63 if (!v) vclass = BEST_VISUAL;
64 else if (!strcmp (v, "default")) vclass = DEFAULT_VISUAL;
65 else if (!strcmp (v, "best")) vclass = BEST_VISUAL;
66 else if (!strcmp (v, "mono")) vclass = MONO_VISUAL;
67 else if (!strcmp (v, "monochrome")) vclass = MONO_VISUAL;
68 else if (!strcmp (v, "gray")) vclass = GRAY_VISUAL;
69 else if (!strcmp (v, "grey")) vclass = GRAY_VISUAL;
70 else if (!strcmp (v, "color")) vclass = COLOR_VISUAL;
71 else if (!strcmp (v, "staticgray")) vclass = StaticGray;
72 else if (!strcmp (v, "staticcolor")) vclass = StaticColor;
73 else if (!strcmp (v, "truecolor")) vclass = TrueColor;
74 else if (!strcmp (v, "grayscale")) vclass = GrayScale;
75 else if (!strcmp (v, "greyscale")) vclass = GrayScale;
76 else if (!strcmp (v, "pseudocolor")) vclass = PseudoColor;
77 else if (!strcmp (v, "directcolor")) vclass = DirectColor;
78 else if (1 == sscanf (v, " %ld %c", &id, &c)) vclass = SPECIFIC_VISUAL;
79 else if (1 == sscanf (v, " 0x%lx %c", &id, &c)) vclass = SPECIFIC_VISUAL;
82 fprintf (stderr, "%s: unrecognized visual \"%s\".\n", progname, v);
83 vclass = DEFAULT_VISUAL;
86 if (vclass == DEFAULT_VISUAL)
87 result = DefaultVisualOfScreen (screen);
88 else if (vclass == BEST_VISUAL)
89 result = pick_best_visual (screen, prefer_writable_cells, False);
90 else if (vclass == MONO_VISUAL)
92 result = pick_mono_visual (screen);
93 if (!result && verbose_p)
94 fprintf (stderr, "%s: no monochrome visuals.\n", progname);
96 else if (vclass == GRAY_VISUAL)
98 if (prefer_writable_cells)
99 result = pick_best_visual_of_class (screen, GrayScale);
101 result = pick_best_visual_of_class (screen, StaticGray);
103 result = pick_best_visual_of_class (screen, GrayScale);
104 if (!result && verbose_p)
105 fprintf (stderr, "%s: no GrayScale or StaticGray visuals.\n",
108 else if (vclass == COLOR_VISUAL)
111 /* First see if the default visual will do. */
112 result = DefaultVisualOfScreen (screen);
113 class = visual_class(screen, result);
114 if (class != TrueColor &&
115 class != PseudoColor &&
116 class != DirectColor &&
117 class != StaticColor)
119 if (result && visual_depth(screen, result) <= 1)
122 /* Else, find the best non-default color visual */
124 result = pick_best_visual (screen, prefer_writable_cells, True);
126 if (!result && verbose_p)
127 fprintf (stderr, "%s: no color visuals.\n", progname);
129 else if (vclass == SPECIFIC_VISUAL)
131 result = id_to_visual (screen, id);
132 if (!result && verbose_p)
133 fprintf (stderr, "%s: no visual with id 0x%x.\n", progname,
138 Visual *visual = pick_best_visual_of_class (screen, vclass);
142 fprintf (stderr, "%s: no visual of class %s.\n", progname, v);
150 get_visual_resource (Screen *screen, char *name, char *class,
151 Bool prefer_writable_cells)
153 char *string = get_string_resource (name, class);
154 Visual *v = get_visual (screen, string, prefer_writable_cells, True);
160 return DefaultVisualOfScreen (screen);
165 pick_best_visual (Screen *screen, Bool prefer_writable_cells, Bool color_only)
169 if (!prefer_writable_cells)
171 /* If we don't prefer writable cells, then the "best" visual is the one
172 on which we can allocate the largest range and number of colors.
174 Therefore, a TrueColor visual which is at least 16 bits deep is best.
175 (The assumption here being that a TrueColor of less than 16 bits is
176 really just a PseudoColor visual with a pre-allocated color cube.)
178 The next best thing is a PseudoColor visual of any type. After that
179 come the non-colormappable visuals, and non-color visuals.
181 if ((visual = pick_best_visual_of_class (screen, TrueColor)) &&
182 visual_depth (screen, visual) >= 16)
186 #define TRY_CLASS(CLASS) \
187 if ((visual = pick_best_visual_of_class (screen, CLASS)) && \
188 (!color_only || visual_depth(screen, visual) > 1)) \
190 TRY_CLASS(PseudoColor);
191 TRY_CLASS(TrueColor);
192 TRY_CLASS(DirectColor);
193 TRY_CLASS(StaticColor);
196 TRY_CLASS(GrayScale);
197 TRY_CLASS(StaticGray);
201 visual = DefaultVisualOfScreen (screen);
202 if (!color_only || visual_depth(screen, visual) > 1)
209 pick_mono_visual (Screen *screen)
211 Display *dpy = DisplayOfScreen (screen);
212 XVisualInfo vi_in, *vi_out;
216 vi_in.screen = screen_number (screen);
217 vi_out = XGetVisualInfo (dpy, (VisualDepthMask | VisualScreenMask),
221 Visual *v = (out_count > 0 ? vi_out [0].visual : 0);
222 if (v && vi_out[0].depth != 1)
224 XFree ((char *) vi_out);
233 pick_best_visual_of_class (Screen *screen, int visual_class)
235 /* The best visual of a class is the one which on which we can allocate
236 the largest range and number of colors, which means the one with the
237 greatest depth and number of cells.
239 (But actually, for XDaliClock, all visuals of the same class are
240 probably equivalent - either we have writable cells or we don't.)
242 Display *dpy = DisplayOfScreen (screen);
243 XVisualInfo vi_in, *vi_out;
246 vi_in.class = visual_class;
247 vi_in.screen = screen_number (screen);
248 vi_out = XGetVisualInfo (dpy, (VisualClassMask | VisualScreenMask),
252 /* choose the 'best' one, if multiple */
255 for (i = 0, best = 0; i < out_count; i++)
256 /* It's better if it's deeper, or if it's the same depth with
257 more cells (does that ever happen? Well, it could...) */
258 if ((vi_out [i].depth > vi_out [best].depth) ||
259 ((vi_out [i].depth == vi_out [best].depth) &&
260 (vi_out [i].colormap_size > vi_out [best].colormap_size)))
262 visual = (best < out_count ? vi_out [best].visual : 0);
263 XFree ((char *) vi_out);
271 id_to_visual (Screen *screen, int id)
273 Display *dpy = DisplayOfScreen (screen);
274 XVisualInfo vi_in, *vi_out;
276 vi_in.screen = screen_number (screen);
278 vi_out = XGetVisualInfo (dpy, (VisualScreenMask | VisualIDMask),
282 Visual *v = vi_out[0].visual;
283 XFree ((char *) vi_out);
290 visual_depth (Screen *screen, Visual *visual)
292 Display *dpy = DisplayOfScreen (screen);
293 XVisualInfo vi_in, *vi_out;
295 vi_in.screen = screen_number (screen);
296 vi_in.visualid = XVisualIDFromVisual (visual);
297 vi_out = XGetVisualInfo (dpy, VisualScreenMask|VisualIDMask,
299 if (! vi_out) abort ();
300 d = vi_out [0].depth;
301 XFree ((char *) vi_out);
307 visual_class (Screen *screen, Visual *visual)
309 Display *dpy = DisplayOfScreen (screen);
310 XVisualInfo vi_in, *vi_out;
312 vi_in.screen = screen_number (screen);
313 vi_in.visualid = XVisualIDFromVisual (visual);
314 vi_out = XGetVisualInfo (dpy, VisualScreenMask|VisualIDMask,
316 if (! vi_out) abort ();
317 c = vi_out [0].class;
318 XFree ((char *) vi_out);
323 has_writable_cells (Screen *screen, Visual *visual)
325 switch (visual_class (screen, visual))
327 case GrayScale: /* Mappable grays. */
328 case PseudoColor: /* Mappable colors. */
330 case StaticGray: /* Fixed grays. */
331 case TrueColor: /* Fixed colors. */
332 case StaticColor: /* (What's the difference again?) */
333 case DirectColor: /* DirectColor visuals are like TrueColor, but have
334 three colormaps - one for each component of RGB.
343 describe_visual (FILE *f, Screen *screen, Visual *visual)
345 Display *dpy = DisplayOfScreen (screen);
346 XVisualInfo vi_in, *vi_out;
348 vi_in.screen = screen_number (screen);
349 vi_in.visualid = XVisualIDFromVisual (visual);
350 vi_out = XGetVisualInfo (dpy, (VisualScreenMask | VisualIDMask),
352 if (! vi_out) abort ();
353 fprintf (f, "0x%02x (%s depth: %2d, cmap: %3d)\n",
354 (unsigned int) vi_out->visualid,
355 (vi_out->class == StaticGray ? "StaticGray, " :
356 vi_out->class == StaticColor ? "StaticColor," :
357 vi_out->class == TrueColor ? "TrueColor, " :
358 vi_out->class == GrayScale ? "GrayScale, " :
359 vi_out->class == PseudoColor ? "PseudoColor," :
360 vi_out->class == DirectColor ? "DirectColor," :
362 vi_out->depth, vi_out->colormap_size /*, vi_out->bits_per_rgb*/);
363 XFree ((char *) vi_out);
367 screen_number (Screen *screen)
369 Display *dpy = DisplayOfScreen (screen);
371 for (i = 0; i < ScreenCount (dpy); i++)
372 if (ScreenOfDisplay (dpy, i) == screen)
378 visual_cells (Screen *screen, Visual *visual)
380 Display *dpy = DisplayOfScreen (screen);
381 XVisualInfo vi_in, *vi_out;
383 vi_in.screen = screen_number (screen);
384 vi_in.visualid = XVisualIDFromVisual (visual);
385 vi_out = XGetVisualInfo (dpy, VisualScreenMask|VisualIDMask,
387 if (! vi_out) abort ();
388 c = vi_out [0].colormap_size;
389 XFree ((char *) vi_out);
394 find_similar_visual(Screen *screen, Visual *old_visual)
396 Display *dpy = DisplayOfScreen (screen);
397 XVisualInfo vi_in, *vi_out;
401 vi_in.screen = screen_number (screen);
402 vi_in.class = visual_class (screen, old_visual);
403 vi_in.depth = visual_depth (screen, old_visual);
405 /* Look for a visual of the same class and depth.
407 vi_out = XGetVisualInfo (dpy, (VisualScreenMask | VisualClassMask |
410 if (vi_out && out_count > 0)
411 result = vi_out[0].visual;
412 if (vi_out) XFree (vi_out);
415 /* Failing that, look for a visual of the same class.
419 vi_out = XGetVisualInfo (dpy, (VisualScreenMask | VisualClassMask),
421 if (vi_out && out_count > 0)
422 result = vi_out[0].visual;
423 if (vi_out) XFree (vi_out);
427 /* Failing that, return the default visual. */
429 result = DefaultVisualOfScreen (screen);