/* Pango * pango-context.c: Contexts for itemization and shaping * * Copyright (C) 2000 Red Hat Software * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #include #include #include "pango/pango-context.h" #include "pango/pango-utils.h" #include "pango-engine.h" #include "pango-engine-private.h" #include "pango-modules.h" struct _PangoContext { GObject parent_instance; PangoLanguage *language; PangoDirection base_dir; PangoFontDescription *font_desc; PangoFontMap *font_map; }; struct _PangoContextClass { GObjectClass parent_class; }; static void pango_context_init (PangoContext *context); static void pango_context_class_init (PangoContextClass *klass); static void pango_context_finalize (GObject *object); static gpointer parent_class; GType pango_context_get_type (void) { static GType object_type = 0; if (!object_type) { static const GTypeInfo object_info = { sizeof (PangoContextClass), (GBaseInitFunc) NULL, (GBaseFinalizeFunc) NULL, (GClassInitFunc) pango_context_class_init, NULL, /* class_finalize */ NULL, /* class_data */ sizeof (PangoContext), 0, /* n_preallocs */ (GInstanceInitFunc) pango_context_init, }; object_type = g_type_register_static (G_TYPE_OBJECT, "PangoContext", &object_info, 0); } return object_type; } static void pango_context_init (PangoContext *context) { context->base_dir = PANGO_DIRECTION_LTR; context->language = NULL; context->font_map = NULL; context->font_desc = pango_font_description_new (); pango_font_description_set_family (context->font_desc, "serif"); pango_font_description_set_style (context->font_desc, PANGO_STYLE_NORMAL); pango_font_description_set_variant (context->font_desc, PANGO_VARIANT_NORMAL); pango_font_description_set_weight (context->font_desc, PANGO_WEIGHT_NORMAL); pango_font_description_set_stretch (context->font_desc, PANGO_STRETCH_NORMAL); pango_font_description_set_size (context->font_desc, 12 * PANGO_SCALE); } static void pango_context_class_init (PangoContextClass *klass) { GObjectClass *object_class = G_OBJECT_CLASS (klass); parent_class = g_type_class_peek_parent (klass); object_class->finalize = pango_context_finalize; } static void pango_context_finalize (GObject *object) { PangoContext *context; context = PANGO_CONTEXT (object); if (context->font_map) g_object_unref (context->font_map); pango_font_description_free (context->font_desc); G_OBJECT_CLASS (parent_class)->finalize (object); } /** * pango_context_new: * * Creates a new #PangoContext initialized to default value. * * This function is only useful when implementing a new backend * for Pango, something applications won't do. You should use * the context creation function for the backend you are using, * for example, pango_xft_get_context(), pango_win32_get_context() * or, pango_ft2_font_map_create_context(). * * If you are using Pango as part of a higher-level system, * that system may have it's own ways of create a #PangoContext. * For instance, the GTK+ toolkit has, among others, * gdk_pango_context_get_for_screen(), and * gtk_widget_get_pango_context(). * * Return value: the new #PangoContext **/ PangoContext * pango_context_new (void) { PangoContext *context; context = g_object_new (PANGO_TYPE_CONTEXT, NULL); return context; } /** * pango_context_set_font_map: * @context: a #PangoContext * @font_map: the #PangoFontMap to set. * * Sets the font map to be searched when fonts are looked-up in this context. * This is only for internal use by Pango backends, a #PangoContext obtained * via one of the recommended methods should already have a suitable font map. **/ void pango_context_set_font_map (PangoContext *context, PangoFontMap *font_map) { g_return_if_fail (PANGO_IS_CONTEXT (context)); g_return_if_fail (!font_map || PANGO_IS_FONT_MAP (font_map)); if (context->font_map) g_object_unref (context->font_map); if (font_map) g_object_ref (font_map); context->font_map = font_map; } /** * pango_context_list_families: * @context: a #PangoContext * @families: location to store a pointer to an array of PangoFontFamily *. * This array should be freed with g_free(). * @n_families: location to store the number of elements in @descs * * List all families for a context. **/ void pango_context_list_families (PangoContext *context, PangoFontFamily ***families, int *n_families) { g_return_if_fail (context != NULL); g_return_if_fail (families == NULL || n_families != NULL); if (n_families == NULL) return; if (context->font_map == NULL) { *n_families = 0; if (families) *families = NULL; return; } else pango_font_map_list_families (context->font_map, families, n_families); } /** * pango_context_load_font: * @context: a #PangoContext * @desc: a #PangoFontDescription describing the font to load * * Loads the font in one of the fontmaps in the context * that is the closest match for @desc. * * Returns the font loaded, or %NULL if no font matched. **/ PangoFont * pango_context_load_font (PangoContext *context, const PangoFontDescription *desc) { g_return_val_if_fail (context != NULL, NULL); g_return_val_if_fail (pango_font_description_get_family (desc) != NULL, NULL); g_return_val_if_fail (pango_font_description_get_size (desc) != 0, NULL); return pango_font_map_load_font (context->font_map, context, desc); } /** * pango_context_load_fontset: * @context: a #PangoContext * @desc: a #PangoFontDescription describing the fonts to load * @language: a #PangoLanguage the fonts will be used for * * Load a set of fonts in the context that can be used to render * a font matching @desc. * * Returns the fontset, or %NULL if no font matched. **/ PangoFontset * pango_context_load_fontset (PangoContext *context, const PangoFontDescription *desc, PangoLanguage *language) { g_return_val_if_fail (context != NULL, NULL); g_return_val_if_fail (pango_font_description_get_family (desc) != NULL, NULL); g_return_val_if_fail (pango_font_description_get_size (desc) != 0, NULL); return pango_font_map_load_fontset (context->font_map, context, desc, language); } /** * pango_context_set_font_description: * @context: a #PangoContext * @desc: the new pango font description * * Set the default font description for the context **/ void pango_context_set_font_description (PangoContext *context, const PangoFontDescription *desc) { g_return_if_fail (context != NULL); g_return_if_fail (desc != NULL); pango_font_description_free (context->font_desc); context->font_desc = pango_font_description_copy (desc); } /** * pango_context_get_font_description: * @context: a #PangoContext * * Retrieve the default font description for the context. * * Return value: a pointer to the context's default font description. * This value must not be modified or freed. **/ PangoFontDescription * pango_context_get_font_description (PangoContext *context) { g_return_val_if_fail (context != NULL, NULL); return context->font_desc; } /** * pango_context_set_language: * @context: a #PangoContext * @language: the new language tag. * * Sets the global language tag for the context. **/ void pango_context_set_language (PangoContext *context, PangoLanguage *language) { g_return_if_fail (context != NULL); context->language = language; } /** * pango_context_get_language: * @context: a #PangoContext * * Retrieves the global language tag for the context. * * Return value: the global language tag. **/ PangoLanguage * pango_context_get_language (PangoContext *context) { g_return_val_if_fail (context != NULL, NULL); return context->language; } /** * pango_context_set_base_dir: * @context: a #PangoContext * @direction: the new base direction * * Sets the base direction for the context. **/ void pango_context_set_base_dir (PangoContext *context, PangoDirection direction) { g_return_if_fail (context != NULL); context->base_dir = direction; } /** * pango_context_get_base_dir: * @context: * * Retrieves the base direction for the context. * * Return value: the base direction for the context. **/ PangoDirection pango_context_get_base_dir (PangoContext *context) { g_return_val_if_fail (context != NULL, PANGO_DIRECTION_LTR); return context->base_dir; } /**********************************************************************/ static gboolean advance_attr_iterator_to (PangoAttrIterator *iterator, int start_index) { int start_range, end_range; pango_attr_iterator_range (iterator, &start_range, &end_range); while (start_index >= end_range) { if (!pango_attr_iterator_next (iterator)) return FALSE; pango_attr_iterator_range (iterator, &start_range, &end_range); } if (start_range > start_index) g_warning ("In pango_itemize(), the cached iterator passed in " "had already moved beyond the start_index"); return TRUE; } /*************************************************************************** * We cache the results of character,fontset => font,shaper in a hash table ***************************************************************************/ typedef struct { GHashTable *hash; } ShaperFontCache; typedef struct { PangoEngineShape *shape_engine; PangoFont *font; } ShaperFontElement; static void shaper_font_cache_destroy (ShaperFontCache *cache) { g_hash_table_destroy (cache->hash); g_free (cache); } static void shaper_font_element_destroy (ShaperFontElement *element) { if (element->font) g_object_unref (element->font); g_free (element); } static ShaperFontCache * get_shaper_font_cache (PangoFontset *fontset) { ShaperFontCache *cache; static GQuark cache_quark = 0; if (!cache_quark) cache_quark = g_quark_from_static_string ("pango-shaper-font-cache"); cache = g_object_get_qdata (G_OBJECT (fontset), cache_quark); if (!cache) { cache = g_new (ShaperFontCache, 1); cache->hash = g_hash_table_new_full (g_direct_hash, NULL, NULL, (GDestroyNotify)shaper_font_element_destroy); g_object_set_qdata_full (G_OBJECT (fontset), cache_quark, cache, (GDestroyNotify)shaper_font_cache_destroy); } return cache; } static gboolean shaper_font_cache_get (ShaperFontCache *cache, gunichar wc, PangoEngineShape **shape_engine, PangoFont **font) { ShaperFontElement *element; element = g_hash_table_lookup (cache->hash, GUINT_TO_POINTER (wc)); if (element) { *shape_engine = element->shape_engine; *font = element->font; return TRUE; } else return FALSE; } static void shaper_font_cache_insert (ShaperFontCache *cache, gunichar wc, PangoEngineShape *shape_engine, PangoFont *font) { ShaperFontElement *element = g_new (ShaperFontElement, 1); element->shape_engine = shape_engine; element->font = font; g_hash_table_insert (cache->hash, GUINT_TO_POINTER (wc), element); } /**********************************************************************/ typedef enum { EMBEDDING_CHANGED = 1 << 0, SCRIPT_CHANGED = 1 << 1, LANG_CHANGED = 1 << 2, FONT_CHANGED = 1 << 3, DERIVED_LANG_CHANGED = 1 << 4 } ChangedFlags; typedef struct _ItemizeState ItemizeState; struct _ItemizeState { PangoContext *context; const char *text; const char *end; const char *run_start; const char *run_end; GList *result; PangoItem *item; guint8 *embedding_levels; int embedding_end_offset; const char *embedding_end; guint8 embedding; PangoAttrIterator *attr_iter; gboolean free_attr_iter; const char *attr_end; PangoFontDescription *font_desc; PangoLanguage *lang; GSList *extra_attrs; gboolean copy_extra_attrs; ChangedFlags changed; PangoScriptIter *script_iter; const char *script_end; PangoScript script; PangoLanguage *derived_lang; PangoEngineLang *lang_engine; PangoFontset *current_fonts; ShaperFontCache *cache; GSList *exact_engines; GSList *fallback_engines; }; static void update_embedding_end (ItemizeState *state) { state->embedding = state->embedding_levels[state->embedding_end_offset]; while (state->embedding_end < state->end && state->embedding_levels[state->embedding_end_offset] == state->embedding) { state->embedding_end_offset++; state->embedding_end = g_utf8_next_char (state->embedding_end); } state->changed |= EMBEDDING_CHANGED; } static void update_attr_iterator (ItemizeState *state) { PangoLanguage *old_lang; int end_index; pango_attr_iterator_range (state->attr_iter, NULL, &end_index); if (end_index < state->end - state->text) state->attr_end = state->text + end_index; else state->attr_end = state->end; old_lang = state->lang; state->font_desc = pango_font_description_copy_static (state->context->font_desc); pango_attr_iterator_get_font (state->attr_iter, state->font_desc, &state->lang, &state->extra_attrs); state->copy_extra_attrs = FALSE; state->changed |= FONT_CHANGED; if (state->lang != old_lang) state->changed |= LANG_CHANGED; } static void update_end (ItemizeState *state) { state->run_end = state->embedding_end; if (state->attr_end < state->run_end) state->run_end = state->attr_end; if (state->script_end < state->run_end) state->run_end = state->script_end; } static void itemize_state_init (ItemizeState *state, PangoContext *context, const char *text, int start_index, int length, PangoAttrList *attrs, PangoAttrIterator *cached_iter) { PangoDirection base_dir; gunichar *text_ucs4; long n_chars; state->context = context; state->text = text; state->end = text + start_index + length; state->result = NULL; state->item = NULL; state->run_start = text + start_index; /* First, apply the bidirectional algorithm to break * the text into directional runs. */ base_dir = context->base_dir; text_ucs4 = g_utf8_to_ucs4_fast (text + start_index, length, &n_chars); state->embedding_levels = g_new (guint8, n_chars); pango_log2vis_get_embedding_levels (text_ucs4, n_chars, &base_dir, state->embedding_levels); g_free (text_ucs4); state->embedding_end_offset = 0; state->embedding_end = text + start_index; update_embedding_end (state); /* Initialize the attribute iterator */ if (cached_iter) { state->attr_iter = cached_iter; state->free_attr_iter = FALSE; } else { state->attr_iter = pango_attr_list_get_iterator (attrs); state->free_attr_iter = TRUE; } state->lang = NULL; advance_attr_iterator_to (state->attr_iter, start_index); update_attr_iterator (state); /* Initialize the script iterator */ state->script_iter = pango_script_iter_new (text + start_index, length); pango_script_iter_get_range (state->script_iter, NULL, &state->script_end, &state->script); update_end (state); state->derived_lang = NULL; state->lang_engine = NULL; state->current_fonts = NULL; state->cache = NULL; state->exact_engines = NULL; state->fallback_engines = NULL; state->changed = EMBEDDING_CHANGED | SCRIPT_CHANGED | LANG_CHANGED | FONT_CHANGED; } static gboolean itemize_state_next (ItemizeState *state) { if (state->run_end == state->end) return FALSE; state->changed = 0; state->run_start = state->run_end; if (state->run_end == state->embedding_end) { update_embedding_end (state); } if (state->run_end == state->attr_end) { pango_attr_iterator_next (state->attr_iter); update_attr_iterator (state); } if (state->run_end == state->script_end) { pango_script_iter_next (state->script_iter); pango_script_iter_get_range (state->script_iter, NULL, &state->script_end, &state->script); state->changed |= SCRIPT_CHANGED; } update_end (state); return TRUE; } static GSList * copy_attr_slist (GSList *attr_slist) { GSList *new_list = NULL; GSList *l; for (l = attr_slist; l; l = l->next) new_list = g_slist_prepend (new_list, pango_attribute_copy (l->data)); return g_slist_reverse (new_list); } static void itemize_state_fill_shaper (ItemizeState *state, PangoEngineShape *shape_engine, PangoFont *font) { GList *l; for (l = state->result; l; l = l->next) { PangoItem *item = l->data; if (item->analysis.shape_engine) break; item->analysis.font = g_object_ref (font); item->analysis.shape_engine = shape_engine; } } static void itemize_state_add_character (ItemizeState *state, PangoEngineShape *shape_engine, PangoFont *font, gboolean force_break, const char *pos) { if (state->item) { if (!state->item->analysis.shape_engine && shape_engine) { itemize_state_fill_shaper (state, shape_engine, font); } else if (state->item->analysis.shape_engine && !shape_engine) { font = state->item->analysis.font; shape_engine = state->item->analysis.shape_engine; } if (!force_break && state->item->analysis.lang_engine == state->lang_engine && state->item->analysis.shape_engine == shape_engine && state->item->analysis.font == font) { state->item->num_chars++; return; } state->item->length = (pos - state->text) - state->item->offset; } state->item = pango_item_new (); state->item->offset = pos - state->text; state->item->length = 0; state->item->num_chars = 1; state->item->analysis.shape_engine = shape_engine; state->item->analysis.lang_engine = state->lang_engine; if (font) g_object_ref (font); state->item->analysis.font = font; state->item->analysis.level = state->embedding; state->item->analysis.language = state->derived_lang; if (state->copy_extra_attrs) { state->item->analysis.extra_attrs = copy_attr_slist (state->extra_attrs); } else { state->item->analysis.extra_attrs = state->extra_attrs; state->copy_extra_attrs = TRUE; } state->result = g_list_prepend (state->result, state->item); } static void get_engines (PangoContext *context, PangoLanguage *lang, PangoScript script, GSList **exact_engines, GSList **fallback_engines) { const char *engine_type = pango_font_map_get_shape_engine_type (context->font_map); PangoMap *shaper_map = pango_find_map (lang, g_quark_from_string (PANGO_ENGINE_TYPE_SHAPE), g_quark_from_string (engine_type)); pango_map_get_engines (shaper_map, script, exact_engines, fallback_engines); } typedef struct { PangoLanguage *lang; gunichar wc; GSList *engines; PangoEngineShape *shape_engine; PangoFont *font; } GetShaperFontInfo; static gboolean get_shaper_and_font_foreach (PangoFontset *fontset, PangoFont *font, gpointer data) { GetShaperFontInfo *info = data; GSList *l; for (l = info->engines; l; l = l->next) { PangoEngineShape *engine = l->data; PangoCoverageLevel level; level = _pango_engine_shape_covers (engine, font, info->lang, info->wc); if (level != PANGO_COVERAGE_NONE) { info->shape_engine = engine; info->font = g_object_ref (font); return TRUE; } } return FALSE; } static gboolean get_shaper_and_font (ItemizeState *state, gunichar wc, PangoEngineShape **shape_engine, PangoFont **font) { GetShaperFontInfo info; if (shaper_font_cache_get (state->cache, wc, shape_engine, font)) return *shape_engine != NULL; if (!state->exact_engines && !state->fallback_engines) get_engines (state->context, state->derived_lang, state->script, &state->exact_engines, &state->fallback_engines); info.lang = state->derived_lang; info.wc = wc; info.shape_engine = NULL; info.font = NULL; info.engines = state->exact_engines; pango_fontset_foreach (state->current_fonts, get_shaper_and_font_foreach, &info); if (info.shape_engine) { *shape_engine = info.shape_engine; *font = info.font; shaper_font_cache_insert (state->cache, wc, *shape_engine, *font); return TRUE; } info.engines = state->fallback_engines; pango_fontset_foreach (state->current_fonts, get_shaper_and_font_foreach, &info); *shape_engine = info.shape_engine; *font = info.font; shaper_font_cache_insert (state->cache, wc, *shape_engine, *font); return *shape_engine != NULL; } static void itemize_state_reset_shape_engines (ItemizeState *state) { g_slist_free (state->exact_engines); state->exact_engines = NULL; g_slist_free (state->fallback_engines); state->fallback_engines = NULL; } static PangoLanguage * compute_derived_language (PangoLanguage *lang, PangoScript script) { PangoLanguage *derived_lang; /* Make sure the language tag is consistent with the derived * script. There is no point in marking up a section of * Arabic text with the "en" language tag. */ if (lang && pango_language_includes_script (lang, script)) derived_lang = lang; else { derived_lang = pango_script_get_sample_language (script); if (!derived_lang) derived_lang = lang; } return derived_lang; } static PangoMap * get_lang_map (PangoLanguage *lang) { static guint engine_type_id = 0; static guint render_type_id = 0; if (engine_type_id == 0) { engine_type_id = g_quark_from_static_string (PANGO_ENGINE_TYPE_LANG); render_type_id = g_quark_from_static_string (PANGO_RENDER_TYPE_NONE); } return pango_find_map (lang, engine_type_id, render_type_id); } static void itemize_state_update_for_new_run (ItemizeState *state) { if (state->changed & (SCRIPT_CHANGED | LANG_CHANGED)) { PangoLanguage *old_derived_lang = state->derived_lang; state->derived_lang = compute_derived_language (state->lang, state->script); if (old_derived_lang != state->derived_lang) state->changed |= DERIVED_LANG_CHANGED; } if ((state->changed & DERIVED_LANG_CHANGED) || !state->lang_engine) { PangoMap *lang_map = get_lang_map (state->derived_lang); state->lang_engine = (PangoEngineLang *)pango_map_get_engine (lang_map, state->script); } if (state->changed & (SCRIPT_CHANGED | DERIVED_LANG_CHANGED)) itemize_state_reset_shape_engines (state); if (state->changed & (FONT_CHANGED | DERIVED_LANG_CHANGED) && state->current_fonts) { g_object_unref (state->current_fonts); state->current_fonts = NULL; state->cache = NULL; } if (!state->current_fonts) { state->current_fonts = pango_font_map_load_fontset (state->context->font_map, state->context, state->font_desc, state->derived_lang); state->cache = get_shaper_font_cache (state->current_fonts); } } static void itemize_state_process_run (ItemizeState *state) { const char *p; gboolean last_was_forced_break = FALSE; /* Only one character has type G_UNICODE_LINE_SEPARATOR in Unicode 4.0; * update this if that changes. */ #define LINE_SEPARATOR 0x2028 itemize_state_update_for_new_run (state); for (p = state->run_start; p < state->run_end; p = g_utf8_next_char (p)) { gunichar wc = g_utf8_get_char (p); gboolean is_forced_break = (wc == '\t' || wc == LINE_SEPARATOR); PangoEngineShape *shape_engine; PangoFont *font; if (!g_unichar_isgraph (wc)) { shape_engine = NULL; font = NULL; } else get_shaper_and_font (state, wc, &shape_engine, &font); itemize_state_add_character (state, shape_engine, font, is_forced_break || last_was_forced_break, p); last_was_forced_break = is_forced_break; } /* Finish the final item from the current segment */ state->item->length = (p - state->text) - state->item->offset; if (!state->item->analysis.shape_engine) { PangoEngineShape *shape_engine; PangoFont *font; if (!get_shaper_and_font (state, ' ', &shape_engine, &font)) { shape_engine = _pango_get_fallback_shaper (); font = NULL; } itemize_state_fill_shaper (state, shape_engine, font); } state->item = NULL; } static void itemize_state_finish (ItemizeState *state) { g_free (state->embedding_levels); if (state->free_attr_iter) pango_attr_iterator_destroy (state->attr_iter); pango_script_iter_free (state->script_iter); pango_font_description_free (state->font_desc); itemize_state_reset_shape_engines (state); if (state->current_fonts) g_object_unref (state->current_fonts); } /** * pango_itemize: * @context: a structure holding information that affects the itemization process. * @text: the text to itemize. * @start_index: first byte in @text to process * @length: the number of bytes (not characters) to process * after @start_index. * This must be >= 0. * @attrs: the set of attributes that apply to @text. * @cached_iter: Cached attribute iterator, or NULL * * Breaks a piece of text into segments with consistent * directional level and shaping engine. Each byte of @text will * be contained in exactly one of the items in the returned list; * the generated list of items will be in logical order (the start * offsets of the items are ascending). * * @cached_iter should be an iterator over @attrs currently positioned at a * range before or containing @start_index; @cached_iter will be advanced to * the range covering the position just after @start_index + @length. * (i.e. if itemizing in a loop, just keep passing in the same @cached_iter). * * Return value: a GList of PangoItem structures. */ GList * pango_itemize (PangoContext *context, const char *text, int start_index, int length, PangoAttrList *attrs, PangoAttrIterator *cached_iter) { ItemizeState state; g_return_val_if_fail (context != NULL, NULL); g_return_val_if_fail (start_index >= 0, NULL); g_return_val_if_fail (length >= 0, NULL); g_return_val_if_fail (length == 0 || text != NULL, NULL); if (length == 0) return NULL; itemize_state_init (&state, context, text, start_index, length, attrs, cached_iter); do itemize_state_process_run (&state); while (itemize_state_next (&state)); itemize_state_finish (&state); return g_list_reverse (state.result); } /** * pango_context_get_metrics: * @context: a #PangoContext * @desc: a #PangoFontDescription structure * @language: language tag used to determine which script to get the metrics * for, or %NULL to indicate to get the metrics for the entire * font. * * Get overall metric information for a font particular font * description. Since the metrics may be substantially different for * different scripts, a language tag can be provided to indicate that * the metrics should be retrieved that correspond to the script(s) * used by that language. * * The #PangoFontDescription is interpreted in the same way as * by pango_itemize(), and the family name may be a comma separated * list of figures. If characters from multiple of these families * would be used to render the string, then the returned fonts would * be a composite of the metrics for the fonts loaded for the * individual families. * * Returns: a #PangoMetrics object. The caller must call pango_font_metrics_unref() * when finished using the object. **/ PangoFontMetrics * pango_context_get_metrics (PangoContext *context, const PangoFontDescription *desc, PangoLanguage *language) { PangoFontset *current_fonts = NULL; PangoFontMetrics *metrics; g_return_val_if_fail (PANGO_IS_CONTEXT (context), NULL); g_return_val_if_fail (desc != NULL, NULL); current_fonts = pango_font_map_load_fontset (context->font_map, context, desc, language); metrics = pango_fontset_get_metrics (current_fonts); g_object_unref (current_fonts); return metrics; }