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      1 /*
      2  * Copyright 2010, 2012, Soren Sandmann <sandmann (at) cs.au.dk>
      3  * Copyright 2010, 2011, 2012, Red Hat, Inc
      4  *
      5  * Permission is hereby granted, free of charge, to any person obtaining a
      6  * copy of this software and associated documentation files (the "Software"),
      7  * to deal in the Software without restriction, including without limitation
      8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      9  * and/or sell copies of the Software, and to permit persons to whom the
     10  * Software is furnished to do so, subject to the following conditions:
     11  *
     12  * The above copyright notice and this permission notice (including the next
     13  * paragraph) shall be included in all copies or substantial portions of the
     14  * Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     22  * DEALINGS IN THE SOFTWARE.
     23  *
     24  * Author: Soren Sandmann <sandmann (at) cs.au.dk>
     25  */
     26 
     27 #ifdef HAVE_CONFIG_H
     28 #include <config.h>
     29 #endif
     30 #include "pixman-private.h"
     31 
     32 #include <stdlib.h>
     33 
     34 typedef struct glyph_metrics_t glyph_metrics_t;
     35 typedef struct glyph_t glyph_t;
     36 
     37 #define TOMBSTONE ((glyph_t *)0x1)
     38 
     39 /* XXX: These numbers are arbitrary---we've never done any measurements.
     40  */
     41 #define N_GLYPHS_HIGH_WATER  (16384)
     42 #define N_GLYPHS_LOW_WATER   (8192)
     43 #define HASH_SIZE (2 * N_GLYPHS_HIGH_WATER)
     44 #define HASH_MASK (HASH_SIZE - 1)
     45 
     46 struct glyph_t
     47 {
     48     void *		font_key;
     49     void *		glyph_key;
     50     int			origin_x;
     51     int			origin_y;
     52     pixman_image_t *	image;
     53     pixman_link_t	mru_link;
     54 };
     55 
     56 struct pixman_glyph_cache_t
     57 {
     58     int			n_glyphs;
     59     int			n_tombstones;
     60     int			freeze_count;
     61     pixman_list_t	mru;
     62     glyph_t *		glyphs[HASH_SIZE];
     63 };
     64 
     65 static void
     66 free_glyph (glyph_t *glyph)
     67 {
     68     pixman_list_unlink (&glyph->mru_link);
     69     pixman_image_unref (glyph->image);
     70     free (glyph);
     71 }
     72 
     73 static unsigned int
     74 hash (const void *font_key, const void *glyph_key)
     75 {
     76     size_t key = (size_t)font_key + (size_t)glyph_key;
     77 
     78     /* This hash function is based on one found on Thomas Wang's
     79      * web page at
     80      *
     81      *    http://www.concentric.net/~Ttwang/tech/inthash.htm
     82      *
     83      */
     84     key = (key << 15) - key - 1;
     85     key = key ^ (key >> 12);
     86     key = key + (key << 2);
     87     key = key ^ (key >> 4);
     88     key = key + (key << 3) + (key << 11);
     89     key = key ^ (key >> 16);
     90 
     91     return key;
     92 }
     93 
     94 static glyph_t *
     95 lookup_glyph (pixman_glyph_cache_t *cache,
     96 	      void                 *font_key,
     97 	      void                 *glyph_key)
     98 {
     99     unsigned idx;
    100     glyph_t *g;
    101 
    102     idx = hash (font_key, glyph_key);
    103     while ((g = cache->glyphs[idx++ & HASH_MASK]))
    104     {
    105 	if (g != TOMBSTONE			&&
    106 	    g->font_key == font_key		&&
    107 	    g->glyph_key == glyph_key)
    108 	{
    109 	    return g;
    110 	}
    111     }
    112 
    113     return NULL;
    114 }
    115 
    116 static void
    117 insert_glyph (pixman_glyph_cache_t *cache,
    118 	      glyph_t              *glyph)
    119 {
    120     unsigned idx;
    121     glyph_t **loc;
    122 
    123     idx = hash (glyph->font_key, glyph->glyph_key);
    124 
    125     /* Note: we assume that there is room in the table. If there isn't,
    126      * this will be an infinite loop.
    127      */
    128     do
    129     {
    130 	loc = &cache->glyphs[idx++ & HASH_MASK];
    131     } while (*loc && *loc != TOMBSTONE);
    132 
    133     if (*loc == TOMBSTONE)
    134 	cache->n_tombstones--;
    135     cache->n_glyphs++;
    136 
    137     *loc = glyph;
    138 }
    139 
    140 static void
    141 remove_glyph (pixman_glyph_cache_t *cache,
    142 	      glyph_t              *glyph)
    143 {
    144     unsigned idx;
    145 
    146     idx = hash (glyph->font_key, glyph->glyph_key);
    147     while (cache->glyphs[idx & HASH_MASK] != glyph)
    148 	idx++;
    149 
    150     cache->glyphs[idx & HASH_MASK] = TOMBSTONE;
    151     cache->n_tombstones++;
    152     cache->n_glyphs--;
    153 
    154     /* Eliminate tombstones if possible */
    155     if (cache->glyphs[(idx + 1) & HASH_MASK] == NULL)
    156     {
    157 	while (cache->glyphs[idx & HASH_MASK] == TOMBSTONE)
    158 	{
    159 	    cache->glyphs[idx & HASH_MASK] = NULL;
    160 	    cache->n_tombstones--;
    161 	    idx--;
    162 	}
    163     }
    164 }
    165 
    166 static void
    167 clear_table (pixman_glyph_cache_t *cache)
    168 {
    169     int i;
    170 
    171     for (i = 0; i < HASH_SIZE; ++i)
    172     {
    173 	glyph_t *glyph = cache->glyphs[i];
    174 
    175 	if (glyph && glyph != TOMBSTONE)
    176 	    free_glyph (glyph);
    177 
    178 	cache->glyphs[i] = NULL;
    179     }
    180 
    181     cache->n_glyphs = 0;
    182     cache->n_tombstones = 0;
    183 }
    184 
    185 PIXMAN_EXPORT pixman_glyph_cache_t *
    186 pixman_glyph_cache_create (void)
    187 {
    188     pixman_glyph_cache_t *cache;
    189 
    190     if (!(cache = malloc (sizeof *cache)))
    191 	return NULL;
    192 
    193     memset (cache->glyphs, 0, sizeof (cache->glyphs));
    194     cache->n_glyphs = 0;
    195     cache->n_tombstones = 0;
    196     cache->freeze_count = 0;
    197 
    198     pixman_list_init (&cache->mru);
    199 
    200     return cache;
    201 }
    202 
    203 PIXMAN_EXPORT void
    204 pixman_glyph_cache_destroy (pixman_glyph_cache_t *cache)
    205 {
    206     return_if_fail (cache->freeze_count == 0);
    207 
    208     clear_table (cache);
    209 
    210     free (cache);
    211 }
    212 
    213 PIXMAN_EXPORT void
    214 pixman_glyph_cache_freeze (pixman_glyph_cache_t  *cache)
    215 {
    216     cache->freeze_count++;
    217 }
    218 
    219 PIXMAN_EXPORT void
    220 pixman_glyph_cache_thaw (pixman_glyph_cache_t  *cache)
    221 {
    222     if (--cache->freeze_count == 0					&&
    223 	cache->n_glyphs + cache->n_tombstones > N_GLYPHS_HIGH_WATER)
    224     {
    225 	if (cache->n_tombstones > N_GLYPHS_HIGH_WATER)
    226 	{
    227 	    /* More than half the entries are
    228 	     * tombstones. Just dump the whole table.
    229 	     */
    230 	    clear_table (cache);
    231 	}
    232 
    233 	while (cache->n_glyphs > N_GLYPHS_LOW_WATER)
    234 	{
    235 	    glyph_t *glyph = CONTAINER_OF (glyph_t, mru_link, cache->mru.tail);
    236 
    237 	    remove_glyph (cache, glyph);
    238 	    free_glyph (glyph);
    239 	}
    240     }
    241 }
    242 
    243 PIXMAN_EXPORT const void *
    244 pixman_glyph_cache_lookup (pixman_glyph_cache_t  *cache,
    245 			   void                  *font_key,
    246 			   void                  *glyph_key)
    247 {
    248     return lookup_glyph (cache, font_key, glyph_key);
    249 }
    250 
    251 PIXMAN_EXPORT const void *
    252 pixman_glyph_cache_insert (pixman_glyph_cache_t  *cache,
    253 			   void                  *font_key,
    254 			   void                  *glyph_key,
    255 			   int			  origin_x,
    256 			   int                    origin_y,
    257 			   pixman_image_t        *image)
    258 {
    259     glyph_t *glyph;
    260     int32_t width, height;
    261 
    262     return_val_if_fail (cache->freeze_count > 0, NULL);
    263     return_val_if_fail (image->type == BITS, NULL);
    264 
    265     width = image->bits.width;
    266     height = image->bits.height;
    267 
    268     if (cache->n_glyphs >= HASH_SIZE)
    269 	return NULL;
    270 
    271     if (!(glyph = malloc (sizeof *glyph)))
    272 	return NULL;
    273 
    274     glyph->font_key = font_key;
    275     glyph->glyph_key = glyph_key;
    276     glyph->origin_x = origin_x;
    277     glyph->origin_y = origin_y;
    278 
    279     if (!(glyph->image = pixman_image_create_bits (
    280 	      image->bits.format, width, height, NULL, -1)))
    281     {
    282 	free (glyph);
    283 	return NULL;
    284     }
    285 
    286     pixman_image_composite32 (PIXMAN_OP_SRC,
    287 			      image, NULL, glyph->image, 0, 0, 0, 0, 0, 0,
    288 			      width, height);
    289 
    290     if (PIXMAN_FORMAT_A   (glyph->image->bits.format) != 0	&&
    291 	PIXMAN_FORMAT_RGB (glyph->image->bits.format) != 0)
    292     {
    293 	pixman_image_set_component_alpha (glyph->image, TRUE);
    294     }
    295 
    296     pixman_list_prepend (&cache->mru, &glyph->mru_link);
    297 
    298     _pixman_image_validate (glyph->image);
    299     insert_glyph (cache, glyph);
    300 
    301     return glyph;
    302 }
    303 
    304 PIXMAN_EXPORT void
    305 pixman_glyph_cache_remove (pixman_glyph_cache_t  *cache,
    306 			   void                  *font_key,
    307 			   void                  *glyph_key)
    308 {
    309     glyph_t *glyph;
    310 
    311     if ((glyph = lookup_glyph (cache, font_key, glyph_key)))
    312     {
    313 	remove_glyph (cache, glyph);
    314 
    315 	free_glyph (glyph);
    316     }
    317 }
    318 
    319 PIXMAN_EXPORT void
    320 pixman_glyph_get_extents (pixman_glyph_cache_t *cache,
    321 			  int                   n_glyphs,
    322 			  pixman_glyph_t       *glyphs,
    323 			  pixman_box32_t       *extents)
    324 {
    325     int i;
    326 
    327     extents->x1 = extents->y1 = INT32_MAX;
    328     extents->x2 = extents->y2 = INT32_MIN;
    329 
    330     for (i = 0; i < n_glyphs; ++i)
    331     {
    332 	glyph_t *glyph = (glyph_t *)glyphs[i].glyph;
    333 	int x1, y1, x2, y2;
    334 
    335 	x1 = glyphs[i].x - glyph->origin_x;
    336 	y1 = glyphs[i].y - glyph->origin_y;
    337 	x2 = glyphs[i].x - glyph->origin_x + glyph->image->bits.width;
    338 	y2 = glyphs[i].y - glyph->origin_y + glyph->image->bits.height;
    339 
    340 	if (x1 < extents->x1)
    341 	    extents->x1 = x1;
    342 	if (y1 < extents->y1)
    343 	    extents->y1 = y1;
    344 	if (x2 > extents->x2)
    345 	    extents->x2 = x2;
    346 	if (y2 > extents->y2)
    347 	    extents->y2 = y2;
    348     }
    349 }
    350 
    351 /* This function returns a format that is suitable for use as a mask for the
    352  * set of glyphs in question.
    353  */
    354 PIXMAN_EXPORT pixman_format_code_t
    355 pixman_glyph_get_mask_format (pixman_glyph_cache_t *cache,
    356 			      int		    n_glyphs,
    357 			      const pixman_glyph_t *glyphs)
    358 {
    359     pixman_format_code_t format = PIXMAN_a1;
    360     int i;
    361 
    362     for (i = 0; i < n_glyphs; ++i)
    363     {
    364 	const glyph_t *glyph = glyphs[i].glyph;
    365 	pixman_format_code_t glyph_format = glyph->image->bits.format;
    366 
    367 	if (PIXMAN_FORMAT_TYPE (glyph_format) == PIXMAN_TYPE_A)
    368 	{
    369 	    if (PIXMAN_FORMAT_A (glyph_format) > PIXMAN_FORMAT_A (format))
    370 		format = glyph_format;
    371 	}
    372 	else
    373 	{
    374 	    return PIXMAN_a8r8g8b8;
    375 	}
    376     }
    377 
    378     return format;
    379 }
    380 
    381 static pixman_bool_t
    382 box32_intersect (pixman_box32_t *dest,
    383 		 const pixman_box32_t *box1,
    384 		 const pixman_box32_t *box2)
    385 {
    386     dest->x1 = MAX (box1->x1, box2->x1);
    387     dest->y1 = MAX (box1->y1, box2->y1);
    388     dest->x2 = MIN (box1->x2, box2->x2);
    389     dest->y2 = MIN (box1->y2, box2->y2);
    390 
    391     return dest->x2 > dest->x1 && dest->y2 > dest->y1;
    392 }
    393 
    394 PIXMAN_EXPORT void
    395 pixman_composite_glyphs_no_mask (pixman_op_t            op,
    396 				 pixman_image_t        *src,
    397 				 pixman_image_t        *dest,
    398 				 int32_t                src_x,
    399 				 int32_t                src_y,
    400 				 int32_t                dest_x,
    401 				 int32_t                dest_y,
    402 				 pixman_glyph_cache_t  *cache,
    403 				 int                    n_glyphs,
    404 				 const pixman_glyph_t  *glyphs)
    405 {
    406     pixman_region32_t region;
    407     pixman_format_code_t glyph_format = PIXMAN_null;
    408     uint32_t glyph_flags = 0;
    409     pixman_format_code_t dest_format;
    410     uint32_t dest_flags;
    411     pixman_composite_func_t func = NULL;
    412     pixman_implementation_t *implementation = NULL;
    413     pixman_composite_info_t info;
    414     int i;
    415 
    416     _pixman_image_validate (src);
    417     _pixman_image_validate (dest);
    418 
    419     dest_format = dest->common.extended_format_code;
    420     dest_flags = dest->common.flags;
    421 
    422     pixman_region32_init (&region);
    423     if (!_pixman_compute_composite_region32 (
    424 	    &region,
    425 	    src, NULL, dest,
    426 	    src_x - dest_x, src_y - dest_y, 0, 0, 0, 0,
    427 	    dest->bits.width, dest->bits.height))
    428     {
    429 	goto out;
    430     }
    431 
    432     info.op = op;
    433     info.src_image = src;
    434     info.dest_image = dest;
    435     info.src_flags = src->common.flags;
    436     info.dest_flags = dest->common.flags;
    437 
    438     for (i = 0; i < n_glyphs; ++i)
    439     {
    440 	glyph_t *glyph = (glyph_t *)glyphs[i].glyph;
    441 	pixman_image_t *glyph_img = glyph->image;
    442 	pixman_box32_t glyph_box;
    443 	pixman_box32_t *pbox;
    444 	uint32_t extra = FAST_PATH_SAMPLES_COVER_CLIP_NEAREST;
    445 	pixman_box32_t composite_box;
    446 	int n;
    447 
    448 	glyph_box.x1 = dest_x + glyphs[i].x - glyph->origin_x;
    449 	glyph_box.y1 = dest_y + glyphs[i].y - glyph->origin_y;
    450 	glyph_box.x2 = glyph_box.x1 + glyph->image->bits.width;
    451 	glyph_box.y2 = glyph_box.y1 + glyph->image->bits.height;
    452 
    453 	pbox = pixman_region32_rectangles (&region, &n);
    454 
    455 	info.mask_image = glyph_img;
    456 
    457 	while (n--)
    458 	{
    459 	    if (box32_intersect (&composite_box, pbox, &glyph_box))
    460 	    {
    461 		if (glyph_img->common.extended_format_code != glyph_format	||
    462 		    glyph_img->common.flags != glyph_flags)
    463 		{
    464 		    glyph_format = glyph_img->common.extended_format_code;
    465 		    glyph_flags = glyph_img->common.flags;
    466 
    467 		    _pixman_implementation_lookup_composite (
    468 			get_implementation(), op,
    469 			src->common.extended_format_code, src->common.flags,
    470 			glyph_format, glyph_flags | extra,
    471 			dest_format, dest_flags,
    472 			&implementation, &func);
    473 		}
    474 
    475 		info.src_x = src_x + composite_box.x1 - dest_x;
    476 		info.src_y = src_y + composite_box.y1 - dest_y;
    477 		info.mask_x = composite_box.x1 - (dest_x + glyphs[i].x - glyph->origin_x);
    478 		info.mask_y = composite_box.y1 - (dest_y + glyphs[i].y - glyph->origin_y);
    479 		info.dest_x = composite_box.x1;
    480 		info.dest_y = composite_box.y1;
    481 		info.width = composite_box.x2 - composite_box.x1;
    482 		info.height = composite_box.y2 - composite_box.y1;
    483 
    484 		info.mask_flags = glyph_flags;
    485 
    486 		func (implementation, &info);
    487 	    }
    488 
    489 	    pbox++;
    490 	}
    491 	pixman_list_move_to_front (&cache->mru, &glyph->mru_link);
    492     }
    493 
    494 out:
    495     pixman_region32_fini (&region);
    496 }
    497 
    498 static void
    499 add_glyphs (pixman_glyph_cache_t *cache,
    500 	    pixman_image_t *dest,
    501 	    int off_x, int off_y,
    502 	    int n_glyphs, const pixman_glyph_t *glyphs)
    503 {
    504     pixman_format_code_t glyph_format = PIXMAN_null;
    505     uint32_t glyph_flags = 0;
    506     pixman_composite_func_t func = NULL;
    507     pixman_implementation_t *implementation = NULL;
    508     pixman_format_code_t dest_format;
    509     uint32_t dest_flags;
    510     pixman_box32_t dest_box;
    511     pixman_composite_info_t info;
    512     pixman_image_t *white_img = NULL;
    513     pixman_bool_t white_src = FALSE;
    514     int i;
    515 
    516     _pixman_image_validate (dest);
    517 
    518     dest_format = dest->common.extended_format_code;
    519     dest_flags = dest->common.flags;
    520 
    521     info.op = PIXMAN_OP_ADD;
    522     info.dest_image = dest;
    523     info.src_x = 0;
    524     info.src_y = 0;
    525     info.dest_flags = dest_flags;
    526 
    527     dest_box.x1 = 0;
    528     dest_box.y1 = 0;
    529     dest_box.x2 = dest->bits.width;
    530     dest_box.y2 = dest->bits.height;
    531 
    532     for (i = 0; i < n_glyphs; ++i)
    533     {
    534 	glyph_t *glyph = (glyph_t *)glyphs[i].glyph;
    535 	pixman_image_t *glyph_img = glyph->image;
    536 	pixman_box32_t glyph_box;
    537 	pixman_box32_t composite_box;
    538 
    539 	if (glyph_img->common.extended_format_code != glyph_format	||
    540 	    glyph_img->common.flags != glyph_flags)
    541 	{
    542 	    pixman_format_code_t src_format, mask_format;
    543 
    544 	    glyph_format = glyph_img->common.extended_format_code;
    545 	    glyph_flags = glyph_img->common.flags;
    546 
    547 	    if (glyph_format == dest->bits.format)
    548 	    {
    549 		src_format = glyph_format;
    550 		mask_format = PIXMAN_null;
    551 		info.src_flags = glyph_flags | FAST_PATH_SAMPLES_COVER_CLIP_NEAREST;
    552 		info.mask_flags = FAST_PATH_IS_OPAQUE;
    553 		info.mask_image = NULL;
    554 		white_src = FALSE;
    555 	    }
    556 	    else
    557 	    {
    558 		if (!white_img)
    559 		{
    560 		    static const pixman_color_t white = { 0xffff, 0xffff, 0xffff, 0xffff };
    561 
    562 		    if (!(white_img = pixman_image_create_solid_fill (&white)))
    563 			goto out;
    564 
    565 		    _pixman_image_validate (white_img);
    566 		}
    567 
    568 		src_format = PIXMAN_solid;
    569 		mask_format = glyph_format;
    570 		info.src_flags = white_img->common.flags;
    571 		info.mask_flags = glyph_flags | FAST_PATH_SAMPLES_COVER_CLIP_NEAREST;
    572 		info.src_image = white_img;
    573 		white_src = TRUE;
    574 	    }
    575 
    576 	    _pixman_implementation_lookup_composite (
    577 		get_implementation(), PIXMAN_OP_ADD,
    578 		src_format, info.src_flags,
    579 		mask_format, info.mask_flags,
    580 		dest_format, dest_flags,
    581 		&implementation, &func);
    582 	}
    583 
    584 	glyph_box.x1 = glyphs[i].x - glyph->origin_x + off_x;
    585 	glyph_box.y1 = glyphs[i].y - glyph->origin_y + off_y;
    586 	glyph_box.x2 = glyph_box.x1 + glyph->image->bits.width;
    587 	glyph_box.y2 = glyph_box.y1 + glyph->image->bits.height;
    588 
    589 	if (box32_intersect (&composite_box, &glyph_box, &dest_box))
    590 	{
    591 	    int src_x = composite_box.x1 - glyph_box.x1;
    592 	    int src_y = composite_box.y1 - glyph_box.y1;
    593 
    594 	    if (white_src)
    595 		info.mask_image = glyph_img;
    596 	    else
    597 		info.src_image = glyph_img;
    598 
    599 	    info.mask_x = info.src_x = src_x;
    600 	    info.mask_y = info.src_y = src_y;
    601 	    info.dest_x = composite_box.x1;
    602 	    info.dest_y = composite_box.y1;
    603 	    info.width = composite_box.x2 - composite_box.x1;
    604 	    info.height = composite_box.y2 - composite_box.y1;
    605 
    606 	    func (implementation, &info);
    607 
    608 	    pixman_list_move_to_front (&cache->mru, &glyph->mru_link);
    609 	}
    610     }
    611 
    612 out:
    613     if (white_img)
    614 	pixman_image_unref (white_img);
    615 }
    616 
    617 /* Conceptually, for each glyph, (white IN glyph) is PIXMAN_OP_ADDed to an
    618  * infinitely big mask image at the position such that the glyph origin point
    619  * is positioned at the (glyphs[i].x, glyphs[i].y) point.
    620  *
    621  * Then (mask_x, mask_y) in the infinite mask and (src_x, src_y) in the source
    622  * image are both aligned with (dest_x, dest_y) in the destination image. Then
    623  * these three images are composited within the
    624  *
    625  *       (dest_x, dest_y, dst_x + width, dst_y + height)
    626  *
    627  * rectangle.
    628  *
    629  * TODO:
    630  *   - Trim the mask to the destination clip/image?
    631  *   - Trim composite region based on sources, when the op ignores 0s.
    632  */
    633 PIXMAN_EXPORT void
    634 pixman_composite_glyphs (pixman_op_t            op,
    635 			 pixman_image_t        *src,
    636 			 pixman_image_t        *dest,
    637 			 pixman_format_code_t   mask_format,
    638 			 int32_t                src_x,
    639 			 int32_t                src_y,
    640 			 int32_t		mask_x,
    641 			 int32_t		mask_y,
    642 			 int32_t                dest_x,
    643 			 int32_t                dest_y,
    644 			 int32_t                width,
    645 			 int32_t                height,
    646 			 pixman_glyph_cache_t  *cache,
    647 			 int			n_glyphs,
    648 			 const pixman_glyph_t  *glyphs)
    649 {
    650     pixman_image_t *mask;
    651 
    652     if (!(mask = pixman_image_create_bits (mask_format, width, height, NULL, -1)))
    653 	return;
    654 
    655     if (PIXMAN_FORMAT_A   (mask_format) != 0 &&
    656 	PIXMAN_FORMAT_RGB (mask_format) != 0)
    657     {
    658 	pixman_image_set_component_alpha (mask, TRUE);
    659     }
    660 
    661     add_glyphs (cache, mask, - mask_x, - mask_y, n_glyphs, glyphs);
    662 
    663     pixman_image_composite32 (op, src, mask, dest,
    664 			      src_x, src_y,
    665 			      0, 0,
    666 			      dest_x, dest_y,
    667 			      width, height);
    668 
    669     pixman_image_unref (mask);
    670 }
    671