pixman_image_set_alpha_map(): Disallow alpha map cycles
[profile/ivi/pixman.git] / pixman / pixman-image.c
1 /*
2  * Copyright © 2000 SuSE, Inc.
3  * Copyright © 2007 Red Hat, Inc.
4  *
5  * Permission to use, copy, modify, distribute, and sell this software and its
6  * documentation for any purpose is hereby granted without fee, provided that
7  * the above copyright notice appear in all copies and that both that
8  * copyright notice and this permission notice appear in supporting
9  * documentation, and that the name of SuSE not be used in advertising or
10  * publicity pertaining to distribution of the software without specific,
11  * written prior permission.  SuSE makes no representations about the
12  * suitability of this software for any purpose.  It is provided "as is"
13  * without express or implied warranty.
14  *
15  * SuSE DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL SuSE
17  * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
18  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
19  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
20  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
21  */
22
23 #ifdef HAVE_CONFIG_H
24 #include <config.h>
25 #endif
26
27 #include <stdlib.h>
28 #include <stdio.h>
29 #include <string.h>
30 #include <assert.h>
31
32 #include "pixman-private.h"
33 #include "pixman-combine32.h"
34
35 pixman_bool_t
36 _pixman_init_gradient (gradient_t *                  gradient,
37                        const pixman_gradient_stop_t *stops,
38                        int                           n_stops)
39 {
40     return_val_if_fail (n_stops > 0, FALSE);
41
42     gradient->stops = pixman_malloc_ab (n_stops, sizeof (pixman_gradient_stop_t));
43     if (!gradient->stops)
44         return FALSE;
45
46     memcpy (gradient->stops, stops, n_stops * sizeof (pixman_gradient_stop_t));
47
48     gradient->n_stops = n_stops;
49
50     gradient->stop_range = 0xffff;
51     gradient->common.class = SOURCE_IMAGE_CLASS_UNKNOWN;
52
53     return TRUE;
54 }
55
56 /*
57  * By default, just evaluate the image at 32bpp and expand.  Individual image
58  * types can plug in a better scanline getter if they want to. For example
59  * we  could produce smoother gradients by evaluating them at higher color
60  * depth, but that's a project for the future.
61  */
62 void
63 _pixman_image_get_scanline_generic_64 (pixman_image_t * image,
64                                        int              x,
65                                        int              y,
66                                        int              width,
67                                        uint32_t *       buffer,
68                                        const uint32_t * mask)
69 {
70     uint32_t *mask8 = NULL;
71
72     /* Contract the mask image, if one exists, so that the 32-bit fetch
73      * function can use it.
74      */
75     if (mask)
76     {
77         mask8 = pixman_malloc_ab (width, sizeof(uint32_t));
78         if (!mask8)
79             return;
80
81         pixman_contract (mask8, (uint64_t *)mask, width);
82     }
83
84     /* Fetch the source image into the first half of buffer. */
85     _pixman_image_get_scanline_32 (image, x, y, width, (uint32_t*)buffer, mask8);
86
87     /* Expand from 32bpp to 64bpp in place. */
88     pixman_expand ((uint64_t *)buffer, buffer, PIXMAN_a8r8g8b8, width);
89
90     free (mask8);
91 }
92
93 pixman_image_t *
94 _pixman_image_allocate (void)
95 {
96     pixman_image_t *image = malloc (sizeof (pixman_image_t));
97
98     if (image)
99     {
100         image_common_t *common = &image->common;
101
102         pixman_region32_init (&common->clip_region);
103
104         common->alpha_count = 0;
105         common->have_clip_region = FALSE;
106         common->clip_sources = FALSE;
107         common->transform = NULL;
108         common->repeat = PIXMAN_REPEAT_NONE;
109         common->filter = PIXMAN_FILTER_NEAREST;
110         common->filter_params = NULL;
111         common->n_filter_params = 0;
112         common->alpha_map = NULL;
113         common->component_alpha = FALSE;
114         common->ref_count = 1;
115         common->classify = NULL;
116         common->client_clip = FALSE;
117         common->destroy_func = NULL;
118         common->destroy_data = NULL;
119         common->dirty = TRUE;
120     }
121
122     return image;
123 }
124
125 source_image_class_t
126 _pixman_image_classify (pixman_image_t *image,
127                         int             x,
128                         int             y,
129                         int             width,
130                         int             height)
131 {
132     if (image->common.classify)
133         return image->common.classify (image, x, y, width, height);
134     else
135         return SOURCE_IMAGE_CLASS_UNKNOWN;
136 }
137
138 void
139 _pixman_image_get_scanline_32 (pixman_image_t *image,
140                                int             x,
141                                int             y,
142                                int             width,
143                                uint32_t *      buffer,
144                                const uint32_t *mask)
145 {
146     image->common.get_scanline_32 (image, x, y, width, buffer, mask);
147 }
148
149 /* Even thought the type of buffer is uint32_t *, the function actually expects
150  * a uint64_t *buffer.
151  */
152 void
153 _pixman_image_get_scanline_64 (pixman_image_t *image,
154                                int             x,
155                                int             y,
156                                int             width,
157                                uint32_t *      buffer,
158                                const uint32_t *unused)
159 {
160     image->common.get_scanline_64 (image, x, y, width, buffer, unused);
161 }
162
163 static void
164 image_property_changed (pixman_image_t *image)
165 {
166     image->common.dirty = TRUE;
167 }
168
169 /* Ref Counting */
170 PIXMAN_EXPORT pixman_image_t *
171 pixman_image_ref (pixman_image_t *image)
172 {
173     image->common.ref_count++;
174
175     return image;
176 }
177
178 /* returns TRUE when the image is freed */
179 PIXMAN_EXPORT pixman_bool_t
180 pixman_image_unref (pixman_image_t *image)
181 {
182     image_common_t *common = (image_common_t *)image;
183
184     common->ref_count--;
185
186     if (common->ref_count == 0)
187     {
188         if (image->common.destroy_func)
189             image->common.destroy_func (image, image->common.destroy_data);
190
191         pixman_region32_fini (&common->clip_region);
192
193         if (common->transform)
194             free (common->transform);
195
196         if (common->filter_params)
197             free (common->filter_params);
198
199         if (common->alpha_map)
200             pixman_image_unref ((pixman_image_t *)common->alpha_map);
201
202         if (image->type == LINEAR ||
203             image->type == RADIAL ||
204             image->type == CONICAL)
205         {
206             if (image->gradient.stops)
207                 free (image->gradient.stops);
208         }
209
210         if (image->type == BITS && image->bits.free_me)
211             free (image->bits.free_me);
212
213         free (image);
214
215         return TRUE;
216     }
217
218     return FALSE;
219 }
220
221 PIXMAN_EXPORT void
222 pixman_image_set_destroy_function (pixman_image_t *            image,
223                                    pixman_image_destroy_func_t func,
224                                    void *                      data)
225 {
226     image->common.destroy_func = func;
227     image->common.destroy_data = data;
228 }
229
230 PIXMAN_EXPORT void *
231 pixman_image_get_destroy_data (pixman_image_t *image)
232 {
233   return image->common.destroy_data;
234 }
235
236 void
237 _pixman_image_reset_clip_region (pixman_image_t *image)
238 {
239     image->common.have_clip_region = FALSE;
240 }
241
242 static pixman_bool_t out_of_bounds_workaround = TRUE;
243
244 /* Old X servers rely on out-of-bounds accesses when they are asked
245  * to composite with a window as the source. They create a pixman image
246  * pointing to some bogus position in memory, but then they set a clip
247  * region to the position where the actual bits are.
248  *
249  * Due to a bug in old versions of pixman, where it would not clip
250  * against the image bounds when a clip region was set, this would
251  * actually work. So by default we allow certain out-of-bound access
252  * to happen unless explicitly disabled.
253  *
254  * Fixed X servers should call this function to disable the workaround.
255  */
256 PIXMAN_EXPORT void
257 pixman_disable_out_of_bounds_workaround (void)
258 {
259     out_of_bounds_workaround = FALSE;
260 }
261
262 static pixman_bool_t
263 source_image_needs_out_of_bounds_workaround (bits_image_t *image)
264 {
265     if (image->common.clip_sources                      &&
266         image->common.repeat == PIXMAN_REPEAT_NONE      &&
267         image->common.have_clip_region                  &&
268         out_of_bounds_workaround)
269     {
270         if (!image->common.client_clip)
271         {
272             /* There is no client clip, so if the clip region extends beyond the
273              * drawable geometry, it must be because the X server generated the
274              * bogus clip region.
275              */
276             const pixman_box32_t *extents =
277                 pixman_region32_extents (&image->common.clip_region);
278
279             if (extents->x1 >= 0 && extents->x2 <= image->width &&
280                 extents->y1 >= 0 && extents->y2 <= image->height)
281             {
282                 return FALSE;
283             }
284         }
285
286         return TRUE;
287     }
288
289     return FALSE;
290 }
291
292 static void
293 compute_image_info (pixman_image_t *image)
294 {
295     pixman_format_code_t code;
296     uint32_t flags = 0;
297
298     /* Transform */
299     if (!image->common.transform)
300     {
301         flags |= (FAST_PATH_ID_TRANSFORM        |
302                   FAST_PATH_X_UNIT_POSITIVE     |
303                   FAST_PATH_Y_UNIT_ZERO         |
304                   FAST_PATH_AFFINE_TRANSFORM);
305     }
306     else
307     {
308         flags |= FAST_PATH_HAS_TRANSFORM;
309
310         if (image->common.transform->matrix[2][0] == 0                  &&
311             image->common.transform->matrix[2][1] == 0                  &&
312             image->common.transform->matrix[2][2] == pixman_fixed_1)
313         {
314             flags |= FAST_PATH_AFFINE_TRANSFORM;
315
316             if (image->common.transform->matrix[0][1] == 0 &&
317                 image->common.transform->matrix[1][0] == 0)
318             {
319                 flags |= FAST_PATH_SCALE_TRANSFORM;
320             }
321         }
322
323         if (image->common.transform->matrix[0][0] > 0)
324             flags |= FAST_PATH_X_UNIT_POSITIVE;
325
326         if (image->common.transform->matrix[1][0] == 0)
327             flags |= FAST_PATH_Y_UNIT_ZERO;
328     }
329
330     /* Alpha map */
331     if (!image->common.alpha_map)
332         flags |= FAST_PATH_NO_ALPHA_MAP;
333
334     /* Filter */
335     switch (image->common.filter)
336     {
337     case PIXMAN_FILTER_NEAREST:
338     case PIXMAN_FILTER_FAST:
339         flags |= (FAST_PATH_NEAREST_FILTER | FAST_PATH_NO_CONVOLUTION_FILTER);
340         break;
341
342     case PIXMAN_FILTER_BILINEAR:
343     case PIXMAN_FILTER_GOOD:
344     case PIXMAN_FILTER_BEST:
345         flags |= (FAST_PATH_BILINEAR_FILTER | FAST_PATH_NO_CONVOLUTION_FILTER);
346         break;
347
348     case PIXMAN_FILTER_CONVOLUTION:
349         break;
350
351     default:
352         flags |= FAST_PATH_NO_CONVOLUTION_FILTER;
353         break;
354     }
355
356     /* Repeat mode */
357     switch (image->common.repeat)
358     {
359     case PIXMAN_REPEAT_NONE:
360         flags |= FAST_PATH_NO_REFLECT_REPEAT | FAST_PATH_NO_PAD_REPEAT | FAST_PATH_NO_NORMAL_REPEAT;
361         break;
362
363     case PIXMAN_REPEAT_REFLECT:
364         flags |= FAST_PATH_NO_PAD_REPEAT | FAST_PATH_NO_NONE_REPEAT | FAST_PATH_NO_NORMAL_REPEAT;
365         break;
366
367     case PIXMAN_REPEAT_PAD:
368         flags |= FAST_PATH_NO_REFLECT_REPEAT | FAST_PATH_NO_NONE_REPEAT | FAST_PATH_NO_NORMAL_REPEAT;
369         break;
370
371     default:
372         flags |= FAST_PATH_NO_REFLECT_REPEAT | FAST_PATH_NO_PAD_REPEAT | FAST_PATH_NO_NONE_REPEAT;
373         break;
374     }
375
376     /* Component alpha */
377     if (image->common.component_alpha)
378         flags |= FAST_PATH_COMPONENT_ALPHA;
379     else
380         flags |= FAST_PATH_UNIFIED_ALPHA;
381
382     flags |= (FAST_PATH_NO_ACCESSORS | FAST_PATH_NO_WIDE_FORMAT);
383
384     /* Type specific checks */
385     switch (image->type)
386     {
387     case SOLID:
388         code = PIXMAN_solid;
389
390         if (image->solid.color.alpha == 0xffff)
391             flags |= FAST_PATH_IS_OPAQUE;
392         break;
393
394     case BITS:
395         if (image->bits.width == 1      &&
396             image->bits.height == 1     &&
397             image->common.repeat != PIXMAN_REPEAT_NONE)
398         {
399             code = PIXMAN_solid;
400         }
401         else
402         {
403             code = image->bits.format;
404
405             if (!image->common.transform &&
406                 image->common.repeat == PIXMAN_REPEAT_NORMAL)
407             {
408                 flags |= FAST_PATH_SIMPLE_REPEAT;
409             }
410         }
411
412         if (image->common.repeat != PIXMAN_REPEAT_NONE                          &&
413             !PIXMAN_FORMAT_A (image->bits.format)                               &&
414             PIXMAN_FORMAT_TYPE (image->bits.format) != PIXMAN_TYPE_GRAY         &&
415             PIXMAN_FORMAT_TYPE (image->bits.format) != PIXMAN_TYPE_COLOR)
416         {
417             flags |= FAST_PATH_IS_OPAQUE;
418         }
419
420         if (source_image_needs_out_of_bounds_workaround (&image->bits))
421             flags |= FAST_PATH_NEEDS_WORKAROUND;
422
423         if (image->bits.read_func || image->bits.write_func)
424             flags &= ~FAST_PATH_NO_ACCESSORS;
425
426         if (PIXMAN_FORMAT_IS_WIDE (image->bits.format))
427             flags &= ~FAST_PATH_NO_WIDE_FORMAT;
428         break;
429
430     case LINEAR:
431     case RADIAL:
432         code = PIXMAN_unknown;
433
434         if (image->common.repeat != PIXMAN_REPEAT_NONE)
435         {
436             int i;
437
438             flags |= FAST_PATH_IS_OPAQUE;
439             for (i = 0; i < image->gradient.n_stops; ++i)
440             {
441                 if (image->gradient.stops[i].color.alpha != 0xffff)
442                 {
443                     flags &= ~FAST_PATH_IS_OPAQUE;
444                     break;
445                 }
446             }
447         }
448         break;
449
450     default:
451         code = PIXMAN_unknown;
452         break;
453     }
454
455     /* Both alpha maps and convolution filters can introduce
456      * non-opaqueness in otherwise opaque images. Also
457      * an image with component alpha turned on is only opaque
458      * if all channels are opaque, so we simply turn it off
459      * unconditionally for those images.
460      */
461     if (image->common.alpha_map                                 ||
462         image->common.filter == PIXMAN_FILTER_CONVOLUTION       ||
463         image->common.component_alpha)
464     {
465         flags &= ~FAST_PATH_IS_OPAQUE;
466     }
467
468     image->common.flags = flags;
469     image->common.extended_format_code = code;
470 }
471
472 void
473 _pixman_image_validate (pixman_image_t *image)
474 {
475     if (image->common.dirty)
476     {
477         compute_image_info (image);
478
479         /* It is important that property_changed is
480          * called *after* compute_image_info() because
481          * property_changed() can make use of the flags
482          * to set up accessors etc.
483          */
484         image->common.property_changed (image);
485
486         image->common.dirty = FALSE;
487     }
488
489     if (image->common.alpha_map)
490         _pixman_image_validate ((pixman_image_t *)image->common.alpha_map);
491 }
492
493 PIXMAN_EXPORT pixman_bool_t
494 pixman_image_set_clip_region32 (pixman_image_t *   image,
495                                 pixman_region32_t *region)
496 {
497     image_common_t *common = (image_common_t *)image;
498     pixman_bool_t result;
499
500     if (region)
501     {
502         if ((result = pixman_region32_copy (&common->clip_region, region)))
503             image->common.have_clip_region = TRUE;
504     }
505     else
506     {
507         _pixman_image_reset_clip_region (image);
508
509         result = TRUE;
510     }
511
512     image_property_changed (image);
513
514     return result;
515 }
516
517 PIXMAN_EXPORT pixman_bool_t
518 pixman_image_set_clip_region (pixman_image_t *   image,
519                               pixman_region16_t *region)
520 {
521     image_common_t *common = (image_common_t *)image;
522     pixman_bool_t result;
523
524     if (region)
525     {
526         if ((result = pixman_region32_copy_from_region16 (&common->clip_region, region)))
527             image->common.have_clip_region = TRUE;
528     }
529     else
530     {
531         _pixman_image_reset_clip_region (image);
532
533         result = TRUE;
534     }
535
536     image_property_changed (image);
537
538     return result;
539 }
540
541 PIXMAN_EXPORT void
542 pixman_image_set_has_client_clip (pixman_image_t *image,
543                                   pixman_bool_t   client_clip)
544 {
545     image->common.client_clip = client_clip;
546 }
547
548 PIXMAN_EXPORT pixman_bool_t
549 pixman_image_set_transform (pixman_image_t *          image,
550                             const pixman_transform_t *transform)
551 {
552     static const pixman_transform_t id =
553     {
554         { { pixman_fixed_1, 0, 0 },
555           { 0, pixman_fixed_1, 0 },
556           { 0, 0, pixman_fixed_1 } }
557     };
558
559     image_common_t *common = (image_common_t *)image;
560     pixman_bool_t result;
561
562     if (common->transform == transform)
563         return TRUE;
564
565     if (memcmp (&id, transform, sizeof (pixman_transform_t)) == 0)
566     {
567         free (common->transform);
568         common->transform = NULL;
569         result = TRUE;
570
571         goto out;
572     }
573
574     if (common->transform == NULL)
575         common->transform = malloc (sizeof (pixman_transform_t));
576
577     if (common->transform == NULL)
578     {
579         result = FALSE;
580
581         goto out;
582     }
583
584     memcpy (common->transform, transform, sizeof(pixman_transform_t));
585
586     result = TRUE;
587
588 out:
589     image_property_changed (image);
590
591     return result;
592 }
593
594 PIXMAN_EXPORT void
595 pixman_image_set_repeat (pixman_image_t *image,
596                          pixman_repeat_t repeat)
597 {
598     image->common.repeat = repeat;
599
600     image_property_changed (image);
601 }
602
603 PIXMAN_EXPORT pixman_bool_t
604 pixman_image_set_filter (pixman_image_t *      image,
605                          pixman_filter_t       filter,
606                          const pixman_fixed_t *params,
607                          int                   n_params)
608 {
609     image_common_t *common = (image_common_t *)image;
610     pixman_fixed_t *new_params;
611
612     if (params == common->filter_params && filter == common->filter)
613         return TRUE;
614
615     new_params = NULL;
616     if (params)
617     {
618         new_params = pixman_malloc_ab (n_params, sizeof (pixman_fixed_t));
619         if (!new_params)
620             return FALSE;
621
622         memcpy (new_params,
623                 params, n_params * sizeof (pixman_fixed_t));
624     }
625
626     common->filter = filter;
627
628     if (common->filter_params)
629         free (common->filter_params);
630
631     common->filter_params = new_params;
632     common->n_filter_params = n_params;
633
634     image_property_changed (image);
635     return TRUE;
636 }
637
638 PIXMAN_EXPORT void
639 pixman_image_set_source_clipping (pixman_image_t *image,
640                                   pixman_bool_t   clip_sources)
641 {
642     image->common.clip_sources = clip_sources;
643
644     image_property_changed (image);
645 }
646
647 /* Unlike all the other property setters, this function does not
648  * copy the content of indexed. Doing this copying is simply
649  * way, way too expensive.
650  */
651 PIXMAN_EXPORT void
652 pixman_image_set_indexed (pixman_image_t *        image,
653                           const pixman_indexed_t *indexed)
654 {
655     bits_image_t *bits = (bits_image_t *)image;
656
657     bits->indexed = indexed;
658
659     image_property_changed (image);
660 }
661
662 PIXMAN_EXPORT void
663 pixman_image_set_alpha_map (pixman_image_t *image,
664                             pixman_image_t *alpha_map,
665                             int16_t         x,
666                             int16_t         y)
667 {
668     image_common_t *common = (image_common_t *)image;
669
670     return_if_fail (!alpha_map || alpha_map->type == BITS);
671
672     if (alpha_map && common->alpha_count > 0)
673     {
674         /* If this image is being used as an alpha map itself,
675          * then you can't give it an alpha map of its own.
676          */
677         return;
678     }
679
680     if (alpha_map && alpha_map->common.alpha_map)
681     {
682         /* If the image has an alpha map of its own,
683          * then it can't be used as an alpha map itself
684          */
685         return;
686     }
687
688     if (common->alpha_map != (bits_image_t *)alpha_map)
689     {
690         if (common->alpha_map)
691         {
692             common->alpha_map->common.alpha_count--;
693
694             pixman_image_unref ((pixman_image_t *)common->alpha_map);
695         }
696
697         if (alpha_map)
698         {
699             common->alpha_map = (bits_image_t *)pixman_image_ref (alpha_map);
700
701             common->alpha_map->common.alpha_count++;
702         }
703         else
704         {
705             common->alpha_map = NULL;
706         }
707     }
708
709     common->alpha_origin_x = x;
710     common->alpha_origin_y = y;
711
712     image_property_changed (image);
713 }
714
715 PIXMAN_EXPORT void
716 pixman_image_set_component_alpha   (pixman_image_t *image,
717                                     pixman_bool_t   component_alpha)
718 {
719     image->common.component_alpha = component_alpha;
720
721     image_property_changed (image);
722 }
723
724 PIXMAN_EXPORT pixman_bool_t
725 pixman_image_get_component_alpha   (pixman_image_t       *image)
726 {
727     return image->common.component_alpha;
728 }
729
730 PIXMAN_EXPORT void
731 pixman_image_set_accessors (pixman_image_t *           image,
732                             pixman_read_memory_func_t  read_func,
733                             pixman_write_memory_func_t write_func)
734 {
735     return_if_fail (image != NULL);
736
737     if (image->type == BITS)
738     {
739         image->bits.read_func = read_func;
740         image->bits.write_func = write_func;
741
742         image_property_changed (image);
743     }
744 }
745
746 PIXMAN_EXPORT uint32_t *
747 pixman_image_get_data (pixman_image_t *image)
748 {
749     if (image->type == BITS)
750         return image->bits.bits;
751
752     return NULL;
753 }
754
755 PIXMAN_EXPORT int
756 pixman_image_get_width (pixman_image_t *image)
757 {
758     if (image->type == BITS)
759         return image->bits.width;
760
761     return 0;
762 }
763
764 PIXMAN_EXPORT int
765 pixman_image_get_height (pixman_image_t *image)
766 {
767     if (image->type == BITS)
768         return image->bits.height;
769
770     return 0;
771 }
772
773 PIXMAN_EXPORT int
774 pixman_image_get_stride (pixman_image_t *image)
775 {
776     if (image->type == BITS)
777         return image->bits.rowstride * (int) sizeof (uint32_t);
778
779     return 0;
780 }
781
782 PIXMAN_EXPORT int
783 pixman_image_get_depth (pixman_image_t *image)
784 {
785     if (image->type == BITS)
786         return PIXMAN_FORMAT_DEPTH (image->bits.format);
787
788     return 0;
789 }
790
791 PIXMAN_EXPORT pixman_format_code_t
792 pixman_image_get_format (pixman_image_t *image)
793 {
794     if (image->type == BITS)
795         return image->bits.format;
796
797     return 0;
798 }
799
800 uint32_t
801 _pixman_image_get_solid (pixman_image_t *     image,
802                          pixman_format_code_t format)
803 {
804     uint32_t result;
805
806     _pixman_image_get_scanline_32 (image, 0, 0, 1, &result, NULL);
807
808     /* If necessary, convert RGB <--> BGR. */
809     if (PIXMAN_FORMAT_TYPE (format) != PIXMAN_TYPE_ARGB)
810     {
811         result = (((result & 0xff000000) >>  0) |
812                   ((result & 0x00ff0000) >> 16) |
813                   ((result & 0x0000ff00) >>  0) |
814                   ((result & 0x000000ff) << 16));
815     }
816
817     return result;
818 }