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* An OpenGL based 'interactive canvas' library.
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* Authored By Matthew Allum <mallum@openedhand.com>
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* Copyright (C) 2008 OpenedHand
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses>.
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#include "cogl-pango-glyph-cache.h"
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#include "cogl-pango-private.h"
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/* Minimum width/height for each texture */
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#define MIN_TEXTURE_SIZE 256
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/* All glyph with heights within this margin from each other can be
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put in the same band */
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#define BAND_HEIGHT_ROUND 4
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typedef struct _CoglPangoGlyphCacheKey CoglPangoGlyphCacheKey;
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typedef struct _CoglPangoGlyphCacheTexture CoglPangoGlyphCacheTexture;
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typedef struct _CoglPangoGlyphCacheBand CoglPangoGlyphCacheBand;
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struct _CoglPangoGlyphCache
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/* Hash table to quickly check whether a particular glyph in a
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particular font is already cached */
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GHashTable *hash_table;
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/* List of textures */
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CoglPangoGlyphCacheTexture *textures;
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/* List of horizontal bands of glyphs */
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CoglPangoGlyphCacheBand *bands;
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struct _CoglPangoGlyphCacheKey
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/* Represents one texture that will be used to store glyphs. The
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texture is divided into horizontal bands which all contain glyphs
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of approximatly the same height */
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struct _CoglPangoGlyphCacheTexture
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/* The width and height of the texture which should always be a
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power of two. This can vary so that glyphs larger than
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MIN_TEXTURE_SIZE can use a bigger texture */
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/* The remaining vertical space not taken up by any bands */
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/* The actual texture */
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CoglPangoGlyphCacheTexture *next;
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/* Represents one horizontal band of a texture. Each band contains
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glyphs of a similar height */
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struct _CoglPangoGlyphCacheBand
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/* The y position of the top of the band */
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/* The height of the band */
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/* The remaining horizontal space not taken up by any glyphs */
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/* The size of the texture. Needed to calculate texture
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/* The texture containing this band */
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CoglPangoGlyphCacheBand *next;
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cogl_pango_glyph_cache_value_free (CoglPangoGlyphCacheValue *value)
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cogl_handle_unref (value->texture);
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g_slice_free (CoglPangoGlyphCacheValue, value);
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cogl_pango_glyph_cache_key_free (CoglPangoGlyphCacheKey *key)
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g_object_unref (key->font);
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g_slice_free (CoglPangoGlyphCacheKey, key);
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cogl_pango_glyph_cache_hash_func (gconstpointer key)
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const CoglPangoGlyphCacheKey *cache_key
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= (const CoglPangoGlyphCacheKey *) key;
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/* Generate a number affected by both the font and the glyph
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number. We can safely directly compare the pointers because the
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key holds a reference to the font so it is not possible that a
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different font will have the same memory address */
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return GPOINTER_TO_UINT (cache_key->font) ^ cache_key->glyph;
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cogl_pango_glyph_cache_equal_func (gconstpointer a,
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const CoglPangoGlyphCacheKey *key_a
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= (const CoglPangoGlyphCacheKey *) a;
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const CoglPangoGlyphCacheKey *key_b
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= (const CoglPangoGlyphCacheKey *) b;
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/* We can safely directly compare the pointers for the fonts because
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the key holds a reference to the font so it is not possible that
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a different font will have the same memory address */
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return key_a->font == key_b->font
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&& key_a->glyph == key_b->glyph;
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cogl_pango_glyph_cache_free_textures (CoglPangoGlyphCacheTexture *node)
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CoglPangoGlyphCacheTexture *next;
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cogl_handle_unref (node->texture);
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g_slice_free (CoglPangoGlyphCacheTexture, node);
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cogl_pango_glyph_cache_free_bands (CoglPangoGlyphCacheBand *node)
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CoglPangoGlyphCacheBand *next;
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cogl_handle_unref (node->texture);
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g_slice_free (CoglPangoGlyphCacheBand, node);
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CoglPangoGlyphCache *
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cogl_pango_glyph_cache_new (void)
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CoglPangoGlyphCache *cache;
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cache = g_malloc (sizeof (CoglPangoGlyphCache));
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cache->hash_table = g_hash_table_new_full
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(cogl_pango_glyph_cache_hash_func,
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cogl_pango_glyph_cache_equal_func,
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(GDestroyNotify) cogl_pango_glyph_cache_key_free,
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(GDestroyNotify) cogl_pango_glyph_cache_value_free);
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cache->textures = NULL;
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cogl_pango_glyph_cache_clear (CoglPangoGlyphCache *cache)
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cogl_pango_glyph_cache_free_textures (cache->textures);
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cache->textures = NULL;
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cogl_pango_glyph_cache_free_bands (cache->bands);
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g_hash_table_remove_all (cache->hash_table);
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cogl_pango_glyph_cache_free (CoglPangoGlyphCache *cache)
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cogl_pango_glyph_cache_clear (cache);
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g_hash_table_unref (cache->hash_table);
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CoglPangoGlyphCacheValue *
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cogl_pango_glyph_cache_lookup (CoglPangoGlyphCache *cache,
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CoglPangoGlyphCacheKey key;
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return (CoglPangoGlyphCacheValue *)
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g_hash_table_lookup (cache->hash_table, &key);
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CoglPangoGlyphCacheValue *
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cogl_pango_glyph_cache_set (CoglPangoGlyphCache *cache,
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gconstpointer pixels,
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CoglPangoGlyphCacheBand *band;
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CoglPangoGlyphCacheKey *key;
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CoglPangoGlyphCacheValue *value;
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/* Reserve an extra pixel gap around the glyph so that it can pull
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in blank pixels when linear filtering is enabled */
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/* Round the height up to the nearest multiple of
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band_height = (height + BAND_HEIGHT_ROUND - 1) & ~(BAND_HEIGHT_ROUND - 1);
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/* Look for a band with the same height and enough width available */
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for (band = cache->bands;
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band && (band->height != band_height || band->space_remaining < width);
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CoglPangoGlyphCacheTexture *texture;
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/* Look for a texture with enough vertical space left for a band
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for (texture = cache->textures;
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texture && (texture->space_remaining < band_height
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|| texture->texture_size < width);
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texture = texture->next);
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/* Allocate a new texture that is the nearest power of two
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greater than the band height or the minimum size,
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whichever is lower */
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texture = g_slice_new (CoglPangoGlyphCacheTexture);
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texture->texture_size = MIN_TEXTURE_SIZE;
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while (texture->texture_size < band_height ||
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texture->texture_size < width)
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texture->texture_size *= 2;
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/* Allocate an empty buffer to clear the texture */
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g_malloc0 (texture->texture_size * texture->texture_size);
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cogl_texture_new_from_data (texture->texture_size,
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texture->texture_size,
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COGL_PIXEL_FORMAT_A_8,
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COGL_PIXEL_FORMAT_A_8,
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texture->texture_size,
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texture->space_remaining = texture->texture_size;
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texture->next = cache->textures;
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cache->textures = texture;
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band = g_slice_new (CoglPangoGlyphCacheBand);
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band->top = texture->texture_size - texture->space_remaining;
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band->height = band_height;
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band->space_remaining = texture->texture_size;
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band->texture = cogl_handle_ref (texture->texture);
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band->texture_size = texture->texture_size;
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band->next = cache->bands;
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texture->space_remaining -= band_height;
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band->space_remaining -= width;
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cogl_texture_set_region (band->texture,
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band->space_remaining,
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COGL_PIXEL_FORMAT_A_8,
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key = g_slice_new (CoglPangoGlyphCacheKey);
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key->font = g_object_ref (font);
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value = g_slice_new (CoglPangoGlyphCacheValue);
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value->texture = cogl_handle_ref (band->texture);
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value->tx1 = (float)(band->space_remaining)
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/ band->texture_size;
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value->tx2 = (float)(band->space_remaining + width)
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/ band->texture_size;
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value->ty1 = (float)(band->top)
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/ band->texture_size;
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value->ty2 = (float)(band->top + height)
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/ band->texture_size;
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value->draw_x = draw_x;
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value->draw_y = draw_y;
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value->draw_width = width;
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value->draw_height = height;
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g_hash_table_insert (cache->hash_table, key, value);
added
removed
clutter/pango/cogl-pango-glyph-cache.c
