1 /* GDK - The GIMP Drawing Kit
2 * gdkvisual.c
3 *
4 * Copyright 2001 Sun Microsystems Inc.
5 *
6 * Erwann Chenede <erwann.chenede@sun.com>
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
17 *
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22 #include "config.h"
23
24 #include "gdkvisualprivate.h"
25 #include "gdkscreenprivate.h"
26
27
28 /**
29 * SECTION:visuals
30 * @Short_description: Low-level display hardware information
31 * @Title: Visuals
32 *
33 * A #GdkVisual describes a particular video hardware display format.
34 * It includes information about the number of bits used for each color,
35 * the way the bits are translated into an RGB value for display, and
36 * the way the bits are stored in memory. For example, a piece of display
37 * hardware might support 24-bit color, 16-bit color, or 8-bit color;
38 * meaning 24/16/8-bit pixel sizes. For a given pixel size, pixels can
39 * be in different formats; for example the “red” element of an RGB pixel
40 * may be in the top 8 bits of the pixel, or may be in the lower 4 bits.
41 *
42 * There are several standard visuals. The visual returned by
43 * gdk_screen_get_system_visual() is the system’s default visual, and
44 * the visual returned by gdk_screen_get_rgba_visual() should be used for
45 * creating windows with an alpha channel.
46 *
47 * A number of functions are provided for determining the “best” available
48 * visual. For the purposes of making this determination, higher bit depths
49 * are considered better, and for visuals of the same bit depth,
50 * %GDK_VISUAL_PSEUDO_COLOR is preferred at 8bpp, otherwise, the visual
51 * types are ranked in the order of(highest to lowest)
52 * %GDK_VISUAL_DIRECT_COLOR, %GDK_VISUAL_TRUE_COLOR,
53 * %GDK_VISUAL_PSEUDO_COLOR, %GDK_VISUAL_STATIC_COLOR,
54 * %GDK_VISUAL_GRAYSCALE, then %GDK_VISUAL_STATIC_GRAY.
55 */
56
G_DEFINE_TYPE(GdkVisual,gdk_visual,G_TYPE_OBJECT)57 G_DEFINE_TYPE (GdkVisual, gdk_visual, G_TYPE_OBJECT)
58
59 static void
60 gdk_visual_init (GdkVisual *visual)
61 {
62 }
63
64 static void
gdk_visual_finalize(GObject * object)65 gdk_visual_finalize (GObject *object)
66 {
67 G_OBJECT_CLASS (gdk_visual_parent_class)->finalize (object);
68 }
69
70 static void
gdk_visual_class_init(GdkVisualClass * visual_class)71 gdk_visual_class_init (GdkVisualClass *visual_class)
72 {
73 GObjectClass *object_class = G_OBJECT_CLASS (visual_class);
74
75 object_class->finalize = gdk_visual_finalize;
76 }
77
78 /**
79 * gdk_list_visuals:
80 *
81 * Lists the available visuals for the default screen.
82 * (See gdk_screen_list_visuals())
83 * A visual describes a hardware image data format.
84 * For example, a visual might support 24-bit color, or 8-bit color,
85 * and might expect pixels to be in a certain format.
86 *
87 * Call g_list_free() on the return value when you’re finished with it.
88 *
89 * Returns: (transfer container) (element-type GdkVisual):
90 * a list of visuals; the list must be freed, but not its contents
91 *
92 * Deprecated: 3.22: Use gdk_screen_list_visuals (gdk_screen_get_default ()).
93 */
94 GList*
gdk_list_visuals(void)95 gdk_list_visuals (void)
96 {
97 return gdk_screen_list_visuals (gdk_screen_get_default ());
98 }
99
100 /**
101 * gdk_visual_get_system:
102 *
103 * Get the system’s default visual for the default GDK screen.
104 * This is the visual for the root window of the display.
105 * The return value should not be freed.
106 *
107 * Returns: (transfer none): system visual
108 *
109 * Deprecated: 3.22: Use gdk_screen_get_system_visual (gdk_screen_get_default ()).
110 */
111 GdkVisual*
gdk_visual_get_system(void)112 gdk_visual_get_system (void)
113 {
114 return gdk_screen_get_system_visual (gdk_screen_get_default());
115 }
116
117 /**
118 * gdk_visual_get_best_depth:
119 *
120 * Get the best available depth for the default GDK screen. “Best”
121 * means “largest,” i.e. 32 preferred over 24 preferred over 8 bits
122 * per pixel.
123 *
124 * Returns: best available depth
125 *
126 * Deprecated: 3.22: Visual selection should be done using
127 * gdk_screen_get_system_visual() and gdk_screen_get_rgba_visual()
128 */
129 gint
gdk_visual_get_best_depth(void)130 gdk_visual_get_best_depth (void)
131 {
132 GdkScreen *screen = gdk_screen_get_default();
133
134 return GDK_SCREEN_GET_CLASS(screen)->visual_get_best_depth (screen);
135 }
136
137 /**
138 * gdk_visual_get_best_type:
139 *
140 * Return the best available visual type for the default GDK screen.
141 *
142 * Returns: best visual type
143 *
144 * Deprecated: 3.22: Visual selection should be done using
145 * gdk_screen_get_system_visual() and gdk_screen_get_rgba_visual()
146 */
147 GdkVisualType
gdk_visual_get_best_type(void)148 gdk_visual_get_best_type (void)
149 {
150 GdkScreen *screen = gdk_screen_get_default();
151
152 return GDK_SCREEN_GET_CLASS(screen)->visual_get_best_type (screen);
153 }
154
155 /**
156 * gdk_visual_get_best:
157 *
158 * Get the visual with the most available colors for the default
159 * GDK screen. The return value should not be freed.
160 *
161 * Returns: (transfer none): best visual
162 *
163 * Deprecated: 3.22: Visual selection should be done using
164 * gdk_screen_get_system_visual() and gdk_screen_get_rgba_visual()
165 */
166 GdkVisual*
gdk_visual_get_best(void)167 gdk_visual_get_best (void)
168 {
169 GdkScreen *screen = gdk_screen_get_default();
170
171 return GDK_SCREEN_GET_CLASS(screen)->visual_get_best (screen);
172 }
173
174 /**
175 * gdk_visual_get_best_with_depth:
176 * @depth: a bit depth
177 *
178 * Get the best visual with depth @depth for the default GDK screen.
179 * Color visuals and visuals with mutable colormaps are preferred
180 * over grayscale or fixed-colormap visuals. The return value should
181 * not be freed. %NULL may be returned if no visual supports @depth.
182 *
183 * Returns: (transfer none): best visual for the given depth
184 *
185 * Deprecated: 3.22: Visual selection should be done using
186 * gdk_screen_get_system_visual() and gdk_screen_get_rgba_visual()
187 */
188 GdkVisual*
gdk_visual_get_best_with_depth(gint depth)189 gdk_visual_get_best_with_depth (gint depth)
190 {
191 GdkScreen *screen = gdk_screen_get_default();
192
193 return GDK_SCREEN_GET_CLASS(screen)->visual_get_best_with_depth (screen, depth);
194 }
195
196 /**
197 * gdk_visual_get_best_with_type:
198 * @visual_type: a visual type
199 *
200 * Get the best visual of the given @visual_type for the default GDK screen.
201 * Visuals with higher color depths are considered better. The return value
202 * should not be freed. %NULL may be returned if no visual has type
203 * @visual_type.
204 *
205 * Returns: (transfer none): best visual of the given type
206 *
207 * Deprecated: 3.22: Visual selection should be done using
208 * gdk_screen_get_system_visual() and gdk_screen_get_rgba_visual()
209 */
210 GdkVisual*
gdk_visual_get_best_with_type(GdkVisualType visual_type)211 gdk_visual_get_best_with_type (GdkVisualType visual_type)
212 {
213 GdkScreen *screen = gdk_screen_get_default();
214
215 return GDK_SCREEN_GET_CLASS(screen)->visual_get_best_with_type (screen,
216 visual_type);
217 }
218
219 /**
220 * gdk_visual_get_best_with_both:
221 * @depth: a bit depth
222 * @visual_type: a visual type
223 *
224 * Combines gdk_visual_get_best_with_depth() and
225 * gdk_visual_get_best_with_type().
226 *
227 * Returns: (nullable) (transfer none): best visual with both @depth
228 * and @visual_type, or %NULL if none
229 *
230 * Deprecated: 3.22: Visual selection should be done using
231 * gdk_screen_get_system_visual() and gdk_screen_get_rgba_visual()
232 */
233 GdkVisual*
gdk_visual_get_best_with_both(gint depth,GdkVisualType visual_type)234 gdk_visual_get_best_with_both (gint depth,
235 GdkVisualType visual_type)
236 {
237 GdkScreen *screen = gdk_screen_get_default();
238
239 return GDK_SCREEN_GET_CLASS(screen)->visual_get_best_with_both (screen, depth, visual_type);
240 }
241
242 /**
243 * gdk_query_depths:
244 * @depths: (out) (array length=count) (transfer none): return
245 * location for available depths
246 * @count: return location for number of available depths
247 *
248 * This function returns the available bit depths for the default
249 * screen. It’s equivalent to listing the visuals
250 * (gdk_list_visuals()) and then looking at the depth field in each
251 * visual, removing duplicates.
252 *
253 * The array returned by this function should not be freed.
254 *
255 * Deprecated: 3.22: Visual selection should be done using
256 * gdk_screen_get_system_visual() and gdk_screen_get_rgba_visual()
257 */
258 void
gdk_query_depths(gint ** depths,gint * count)259 gdk_query_depths (gint **depths,
260 gint *count)
261 {
262 GdkScreen *screen = gdk_screen_get_default();
263
264 GDK_SCREEN_GET_CLASS(screen)->query_depths (screen, depths, count);
265 }
266
267 /**
268 * gdk_query_visual_types:
269 * @visual_types: (out) (array length=count) (transfer none): return
270 * location for the available visual types
271 * @count: return location for the number of available visual types
272 *
273 * This function returns the available visual types for the default
274 * screen. It’s equivalent to listing the visuals
275 * (gdk_list_visuals()) and then looking at the type field in each
276 * visual, removing duplicates.
277 *
278 * The array returned by this function should not be freed.
279 *
280 * Deprecated: 3.22: Visual selection should be done using
281 * gdk_screen_get_system_visual() and gdk_screen_get_rgba_visual()
282 */
283 void
gdk_query_visual_types(GdkVisualType ** visual_types,gint * count)284 gdk_query_visual_types (GdkVisualType **visual_types,
285 gint *count)
286 {
287 GdkScreen *screen = gdk_screen_get_default();
288
289 GDK_SCREEN_GET_CLASS(screen)->query_visual_types (screen, visual_types, count);
290 }
291
292 /**
293 * gdk_visual_get_visual_type:
294 * @visual: A #GdkVisual.
295 *
296 * Returns the type of visual this is (PseudoColor, TrueColor, etc).
297 *
298 * Returns: A #GdkVisualType stating the type of @visual.
299 *
300 * Since: 2.22
301 */
302 GdkVisualType
gdk_visual_get_visual_type(GdkVisual * visual)303 gdk_visual_get_visual_type (GdkVisual *visual)
304 {
305 g_return_val_if_fail (GDK_IS_VISUAL (visual), 0);
306
307 return visual->type;
308 }
309
310 /**
311 * gdk_visual_get_depth:
312 * @visual: A #GdkVisual.
313 *
314 * Returns the bit depth of this visual.
315 *
316 * Returns: The bit depth of this visual.
317 *
318 * Since: 2.22
319 */
320 gint
gdk_visual_get_depth(GdkVisual * visual)321 gdk_visual_get_depth (GdkVisual *visual)
322 {
323 g_return_val_if_fail (GDK_IS_VISUAL (visual), 0);
324
325 return visual->depth;
326 }
327
328 /**
329 * gdk_visual_get_byte_order:
330 * @visual: A #GdkVisual.
331 *
332 * Returns the byte order of this visual.
333 *
334 * The information returned by this function is only relevant
335 * when working with XImages, and not all backends return
336 * meaningful information for this.
337 *
338 * Returns: A #GdkByteOrder stating the byte order of @visual.
339 *
340 * Since: 2.22
341 *
342 * Deprecated: 3.22: This information is not useful
343 */
344 GdkByteOrder
gdk_visual_get_byte_order(GdkVisual * visual)345 gdk_visual_get_byte_order (GdkVisual *visual)
346 {
347 g_return_val_if_fail (GDK_IS_VISUAL (visual), 0);
348
349 return visual->byte_order;
350 }
351
352 /**
353 * gdk_visual_get_colormap_size:
354 * @visual: A #GdkVisual.
355 *
356 * Returns the size of a colormap for this visual.
357 *
358 * You have to use platform-specific APIs to manipulate colormaps.
359 *
360 * Returns: The size of a colormap that is suitable for @visual.
361 *
362 * Since: 2.22
363 *
364 * Deprecated: 3.22: This information is not useful, since GDK does not
365 * provide APIs to operate on colormaps.
366 */
367 gint
gdk_visual_get_colormap_size(GdkVisual * visual)368 gdk_visual_get_colormap_size (GdkVisual *visual)
369 {
370 g_return_val_if_fail (GDK_IS_VISUAL (visual), 0);
371
372 return visual->colormap_size;
373 }
374
375 /**
376 * gdk_visual_get_bits_per_rgb:
377 * @visual: a #GdkVisual
378 *
379 * Returns the number of significant bits per red, green and blue value.
380 *
381 * Not all GDK backend provide a meaningful value for this function.
382 *
383 * Returns: The number of significant bits per color value for @visual.
384 *
385 * Since: 2.22
386 *
387 * Deprecated: 3.22. Use gdk_visual_get_red_pixel_details() and its variants to
388 * learn about the pixel layout of TrueColor and DirectColor visuals
389 */
390 gint
gdk_visual_get_bits_per_rgb(GdkVisual * visual)391 gdk_visual_get_bits_per_rgb (GdkVisual *visual)
392 {
393 g_return_val_if_fail (GDK_IS_VISUAL (visual), 0);
394
395 return visual->bits_per_rgb;
396 }
397
398 static void
gdk_visual_get_pixel_details(GdkVisual * visual,gulong pixel_mask,guint32 * mask,gint * shift,gint * precision)399 gdk_visual_get_pixel_details (GdkVisual *visual,
400 gulong pixel_mask,
401 guint32 *mask,
402 gint *shift,
403 gint *precision)
404 {
405 gulong m = 0;
406 gint s = 0;
407 gint p = 0;
408
409 if (pixel_mask != 0)
410 {
411 m = pixel_mask;
412 while (!(m & 0x1))
413 {
414 s++;
415 m >>= 1;
416 }
417
418 while (m & 0x1)
419 {
420 p++;
421 m >>= 1;
422 }
423 }
424
425 if (mask)
426 *mask = pixel_mask;
427
428 if (shift)
429 *shift = s;
430
431 if (precision)
432 *precision = p;
433 }
434
435 /**
436 * gdk_visual_get_red_pixel_details:
437 * @visual: A #GdkVisual
438 * @mask: (out) (allow-none): A pointer to a #guint32 to be filled in, or %NULL
439 * @shift: (out) (allow-none): A pointer to a #gint to be filled in, or %NULL
440 * @precision: (out) (allow-none): A pointer to a #gint to be filled in, or %NULL
441 *
442 * Obtains values that are needed to calculate red pixel values in TrueColor
443 * and DirectColor. The “mask” is the significant bits within the pixel.
444 * The “shift” is the number of bits left we must shift a primary for it
445 * to be in position (according to the "mask"). Finally, "precision" refers
446 * to how much precision the pixel value contains for a particular primary.
447 *
448 * Since: 2.22
449 */
450 void
gdk_visual_get_red_pixel_details(GdkVisual * visual,guint32 * mask,gint * shift,gint * precision)451 gdk_visual_get_red_pixel_details (GdkVisual *visual,
452 guint32 *mask,
453 gint *shift,
454 gint *precision)
455 {
456 g_return_if_fail (GDK_IS_VISUAL (visual));
457
458 gdk_visual_get_pixel_details (visual, visual->red_mask, mask, shift, precision);
459 }
460
461 /**
462 * gdk_visual_get_green_pixel_details:
463 * @visual: a #GdkVisual
464 * @mask: (out) (allow-none): A pointer to a #guint32 to be filled in, or %NULL
465 * @shift: (out) (allow-none): A pointer to a #gint to be filled in, or %NULL
466 * @precision: (out) (allow-none): A pointer to a #gint to be filled in, or %NULL
467 *
468 * Obtains values that are needed to calculate green pixel values in TrueColor
469 * and DirectColor. The “mask” is the significant bits within the pixel.
470 * The “shift” is the number of bits left we must shift a primary for it
471 * to be in position (according to the "mask"). Finally, "precision" refers
472 * to how much precision the pixel value contains for a particular primary.
473 *
474 * Since: 2.22
475 */
476 void
gdk_visual_get_green_pixel_details(GdkVisual * visual,guint32 * mask,gint * shift,gint * precision)477 gdk_visual_get_green_pixel_details (GdkVisual *visual,
478 guint32 *mask,
479 gint *shift,
480 gint *precision)
481 {
482 g_return_if_fail (GDK_IS_VISUAL (visual));
483
484 gdk_visual_get_pixel_details (visual, visual->green_mask, mask, shift, precision);
485 }
486
487 /**
488 * gdk_visual_get_blue_pixel_details:
489 * @visual: a #GdkVisual
490 * @mask: (out) (allow-none): A pointer to a #guint32 to be filled in, or %NULL
491 * @shift: (out) (allow-none): A pointer to a #gint to be filled in, or %NULL
492 * @precision: (out) (allow-none): A pointer to a #gint to be filled in, or %NULL
493 *
494 * Obtains values that are needed to calculate blue pixel values in TrueColor
495 * and DirectColor. The “mask” is the significant bits within the pixel.
496 * The “shift” is the number of bits left we must shift a primary for it
497 * to be in position (according to the "mask"). Finally, "precision" refers
498 * to how much precision the pixel value contains for a particular primary.
499 *
500 * Since: 2.22
501 */
502 void
gdk_visual_get_blue_pixel_details(GdkVisual * visual,guint32 * mask,gint * shift,gint * precision)503 gdk_visual_get_blue_pixel_details (GdkVisual *visual,
504 guint32 *mask,
505 gint *shift,
506 gint *precision)
507 {
508 g_return_if_fail (GDK_IS_VISUAL (visual));
509
510 gdk_visual_get_pixel_details (visual, visual->blue_mask, mask, shift, precision);
511 }
512
513 /**
514 * gdk_visual_get_screen:
515 * @visual: a #GdkVisual
516 *
517 * Gets the screen to which this visual belongs
518 *
519 * Returns: (transfer none): the screen to which this visual belongs.
520 *
521 * Since: 2.2
522 */
523 GdkScreen *
gdk_visual_get_screen(GdkVisual * visual)524 gdk_visual_get_screen (GdkVisual *visual)
525 {
526 g_return_val_if_fail (GDK_IS_VISUAL (visual), NULL);
527
528 return visual->screen;
529 }
530