diff options
Diffstat (limited to 'src/hb-ot-layout.cc')
| -rw-r--r-- | src/hb-ot-layout.cc | 45 |
1 files changed, 44 insertions, 1 deletions
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc index 020b8a6c8..2eb8535db 100644 --- a/src/hb-ot-layout.cc +++ b/src/hb-ot-layout.cc @@ -1241,7 +1241,7 @@ script_collect_features (hb_collect_features_context_t *c, * terminated by %HB_TAG_NONE * @features: (nullable) (array zero-terminated=1): The array of features to collect, * terminated by %HB_TAG_NONE - * @feature_indexes: (out): The array of feature indexes found for the query + * @feature_indexes: (out): The set of feature indexes found for the query * * Fetches a list of all feature indexes in the specified face's GSUB table * or GPOS table, underneath the specified scripts, languages, and features. @@ -1282,6 +1282,49 @@ hb_ot_layout_collect_features (hb_face_t *face, } } +/** + * hb_ot_layout_collect_features_map: + * @face: #hb_face_t to work upon + * @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS + * @script_index: The index of the requested script tag + * @language_index: The index of the requested language tag + * @feature_map: (out): The map of feature tag to feature index. + * + * Fetches the mapping from feature tags to feature indexes for + * the specified script and language. + * + * Since: 8.1.0 + **/ +void +hb_ot_layout_collect_features_map (hb_face_t *face, + hb_tag_t table_tag, + unsigned script_index, + unsigned language_index, + hb_map_t *feature_map /* OUT */) +{ + const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag); + const OT::LangSys &l = g.get_script (script_index).get_lang_sys (language_index); + + unsigned int count = l.get_feature_indexes (0, nullptr, nullptr); + feature_map->alloc (count); + + /* Loop in reverse, such that earlier entries win. That emulates + * a linear search, which seems to be what other implementations do. + * We found that with arialuni_t.ttf, the "ur" language system has + * duplicate features, and the earlier ones work but not later ones. + */ + for (unsigned int i = count; i; i--) + { + unsigned feature_index = 0; + unsigned feature_count = 1; + l.get_feature_indexes (i - 1, &feature_count, &feature_index); + if (!feature_count) + break; + hb_tag_t feature_tag = g.get_feature_tag (feature_index); + feature_map->set (feature_tag, feature_index); + } +} + /** * hb_ot_layout_collect_lookups: |