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[docs] Complete hb-ot-layout docs a bit

This commit is contained in:
Khaled Hosny 2020-12-30 23:37:49 +02:00 committed by Behdad Esfahbod
parent 5b7b730d4b
commit 8e8c3e5878
4 changed files with 101 additions and 26 deletions
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2
docs/harfbuzz-sections.txt
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@ -600,6 +600,8 @@ hb_ot_layout_language_get_required_feature_index
Xhb_ot_layout_lookup_enumerate_sequences
Xhb_ot_layout_lookup_position
Xhb_ot_layout_lookup_substitute
hb_ot_layout_glyph_sequence_t
hb_ot_layout_glyph_sequence_func_t
</SECTION>
<SECTION>

59
src/hb-ot-layout.cc
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@ -410,7 +410,7 @@ get_gsubgpos_table (hb_face_t *face,
/**
* hb_ot_layout_table_get_script_tags:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @start_offset: offset of the first script tag to retrieve
* @script_count: (inout) (allow-none): Input = the maximum number of script tags to return;
* Output = the actual number of script tags returned (may be zero)
@ -437,7 +437,7 @@ hb_ot_layout_table_get_script_tags (hb_face_t *face,
/**
* hb_ot_layout_table_find_script:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @script_tag: #hb_tag_t of the script tag requested
* @script_index: (out): The index of the requested script tag
*
@ -481,7 +481,7 @@ hb_ot_layout_table_find_script (hb_face_t *face,
/**
* hb_ot_layout_table_choose_script:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @script_tags: Array of #hb_tag_t script tags
* @script_index: (out): The index of the requested script tag
* @chosen_script: (out): #hb_tag_t of the script tag requested
@ -504,11 +504,22 @@ hb_ot_layout_table_choose_script (hb_face_t *face,
/**
* hb_ot_layout_table_select_script:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @script_count: Number of script tags in the array
* @script_tags: Array of #hb_tag_t script tags
* @script_index: (out): The index of the requested script
* @chosen_script: (out): #hb_tag_t of the requested script
* @script_index: (out) (optional): The index of the requested script
* @chosen_script: (out) (optional): #hb_tag_t of the requested script
*
* Selects an OpenType script for @table_tag from the @script_tags array.
*
* If the table does not have any of the requested scripts, then `DFLT`,
* `dflt`, and `latn` tags are tried in that order. If the table still does not
* have any of these scripts, @script_index and @chosen_script are set to
* #HB_OT_LAYOUT_NO_SCRIPT_INDEX.
*
* Return value:
* %true if one of the requested scripts is selected, %false if a fallback
* script is selected or if no scripts are selected.
*
* Since: 2.0.0
**/
@ -566,7 +577,7 @@ hb_ot_layout_table_select_script (hb_face_t *face,
/**
* hb_ot_layout_table_get_feature_tags:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @start_offset: offset of the first feature tag to retrieve
* @feature_count: (inout) (allow-none): Input = the maximum number of feature tags to return;
* Output = the actual number of feature tags returned (may be zero)
@ -591,7 +602,7 @@ hb_ot_layout_table_get_feature_tags (hb_face_t *face,
/**
* hb_ot_layout_table_find_feature:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @feature_tag: The #hb_tag_t og the requested feature tag
* @feature_index: (out): The index of the requested feature
*
@ -626,7 +637,7 @@ hb_ot_layout_table_find_feature (hb_face_t *face,
/**
* hb_ot_layout_script_get_language_tags:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @script_index: The index of the requested script tag
* @start_offset: offset of the first language tag to retrieve
* @language_count: (inout) (allow-none): Input = the maximum number of language tags to return;
@ -655,7 +666,7 @@ hb_ot_layout_script_get_language_tags (hb_face_t *face,
/**
* hb_ot_layout_script_find_language:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @script_index: The index of the requested script tag
* @language_tag: The #hb_tag_t of the requested language
* @language_index: The index of the requested language
@ -688,7 +699,7 @@ hb_ot_layout_script_find_language (hb_face_t *face,
/**
* hb_ot_layout_script_select_language:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @script_index: The index of the requested script tag
* @language_count: The number of languages in the specified script
* @language_tags: The array of language tags
@ -731,7 +742,7 @@ hb_ot_layout_script_select_language (hb_face_t *face,
/**
* hb_ot_layout_language_get_required_feature_index:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @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_index: (out): The index of the requested feature
@ -761,7 +772,7 @@ hb_ot_layout_language_get_required_feature_index (hb_face_t *face,
/**
* hb_ot_layout_language_get_required_feature:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @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_index: (out): The index of the requested feature
@ -796,7 +807,7 @@ hb_ot_layout_language_get_required_feature (hb_face_t *face,
/**
* hb_ot_layout_language_get_feature_indexes:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @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
* @start_offset: offset of the first feature tag to retrieve
@ -827,7 +838,7 @@ hb_ot_layout_language_get_feature_indexes (hb_face_t *face,
/**
* hb_ot_layout_language_get_feature_tags:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @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
* @start_offset: offset of the first feature tag to retrieve
@ -868,7 +879,7 @@ hb_ot_layout_language_get_feature_tags (hb_face_t *face,
/**
* hb_ot_layout_language_find_feature:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @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_tag: #hb_tag_t of the feature tag requested
@ -910,7 +921,7 @@ hb_ot_layout_language_find_feature (hb_face_t *face,
/**
* hb_ot_layout_feature_get_lookups:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @feature_index: The index of the requested feature
* @start_offset: offset of the first lookup to retrieve
* @lookup_count: (inout) (allow-none): Input = the maximum number of lookups to return;
@ -944,7 +955,7 @@ hb_ot_layout_feature_get_lookups (hb_face_t *face,
/**
* hb_ot_layout_table_get_lookup_count:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
*
* Fetches the total number of lookups enumerated in the specified
* face's GSUB table or GPOS table.
@ -1101,7 +1112,7 @@ script_collect_features (hb_collect_features_context_t *c,
/**
* hb_ot_layout_collect_features:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @scripts: The array of scripts to collect features for
* @languages: The array of languages to collect features for
* @features: The array of features to collect
@ -1152,7 +1163,7 @@ hb_ot_layout_collect_features (hb_face_t *face,
/**
* hb_ot_layout_collect_lookups:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @scripts: The array of scripts to collect lookups for
* @languages: The array of languages to collect lookups for
* @features: The array of features to collect lookups for
@ -1191,7 +1202,7 @@ hb_ot_layout_collect_lookups (hb_face_t *face,
/**
* hb_ot_layout_lookup_collect_glyphs:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @lookup_index: The index of the feature lookup to query
* @glyphs_before: (out): Array of glyphs preceding the substitution range
* @glyphs_input: (out): Array of input glyphs that would be substituted by the lookup
@ -1243,7 +1254,7 @@ hb_ot_layout_lookup_collect_glyphs (hb_face_t *face,
/**
* hb_ot_layout_table_find_feature_variations:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @coords: The variation coordinates to query
* @num_coords: The number of variation coordinates
* @variations_index: (out): The array of feature variations found for the query
@ -1268,7 +1279,7 @@ hb_ot_layout_table_find_feature_variations (hb_face_t *face,
/**
* hb_ot_layout_feature_with_variations_get_lookups:
* @face: #hb_face_t to work upon
* @table_tag: HB_OT_TAG_GSUB or HB_OT_TAG_GPOS
* @table_tag: #HB_OT_TAG_GSUB or #HB_OT_TAG_GPOS
* @feature_index: The index of the feature to query
* @variations_index: The index of the feature variation to query
* @start_offset: offset of the first lookup to retrieve
@ -1488,6 +1499,8 @@ hb_ot_layout_lookups_substitute_closure (hb_face_t *face,
* hb_ot_layout_has_positioning:
* @face: #hb_face_t to work upon
*
* Tests whether the specified face includes any GPOS positioning.
*
* Return value: %true if the face has GPOS data, %false otherwise
*
**/

51
src/hb-ot-layout.h
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@ -38,10 +38,35 @@
HB_BEGIN_DECLS
/**
* HB_OT_TAG_BASE:
*
* OpenType [Baseline Table](https://docs.microsoft.com/en-us/typography/opentype/spec/base).
*/
#define HB_OT_TAG_BASE HB_TAG('B','A','S','E')
/**
* HB_OT_TAG_GDEF:
*
* OpenType [Glyph Definition Table](https://docs.microsoft.com/en-us/typography/opentype/spec/gdef).
*/
#define HB_OT_TAG_GDEF HB_TAG('G','D','E','F')
/**
* HB_OT_TAG_GSUB:
*
* OpenType [Glyph Substitution Table](https://docs.microsoft.com/en-us/typography/opentype/spec/gsub).
*/
#define HB_OT_TAG_GSUB HB_TAG('G','S','U','B')
/**
* HB_OT_TAG_GPOS:
*
* OpenType [Glyph Positioning Table](https://docs.microsoft.com/en-us/typography/opentype/spec/gpos).
*/
#define HB_OT_TAG_GPOS HB_TAG('G','P','O','S')
/**
* HB_OT_TAG_JSTF:
*
* OpenType [Justification Table](https://docs.microsoft.com/en-us/typography/opentype/spec/jstf).
*/
#define HB_OT_TAG_JSTF HB_TAG('J','S','T','F')
@ -55,12 +80,16 @@ HB_BEGIN_DECLS
/**
* HB_OT_MAX_TAGS_PER_SCRIPT:
*
* Maximum number of OpenType tags that can correspond to a give #hb_script_t.
*
* Since: 2.0.0
**/
#define HB_OT_MAX_TAGS_PER_SCRIPT 3u
/**
* HB_OT_MAX_TAGS_PER_LANGUAGE:
*
* Maximum number of OpenType tags that can correspond to a give #hb_language_t.
*
* Since: 2.0.0
**/
#define HB_OT_MAX_TAGS_PER_LANGUAGE 3u
@ -144,9 +173,29 @@ hb_ot_layout_get_ligature_carets (hb_font_t *font,
* GSUB/GPOS feature query and enumeration interface
*/
/**
* HB_OT_LAYOUT_NO_SCRIPT_INDEX:
*
* Special value for script index indicating unsupported script.
*/
#define HB_OT_LAYOUT_NO_SCRIPT_INDEX 0xFFFFu
/**
* HB_OT_LAYOUT_NO_FEATURE_INDEX:
*
* Special value for feature index indicating unsupported feature.
*/
#define HB_OT_LAYOUT_NO_FEATURE_INDEX 0xFFFFu
/**
* HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX:
*
* Special value for language index indicating default or unsupported language.
*/
#define HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX 0xFFFFu
/**
* HB_OT_LAYOUT_NO_VARIATIONS_INDEX:
*
* Special value for variations index indicating unsupported variation.
*/
#define HB_OT_LAYOUT_NO_VARIATIONS_INDEX 0xFFFFFFFFu
HB_EXTERN unsigned int
@ -433,7 +482,7 @@ hb_ot_layout_feature_get_characters (hb_face_t *face,
* @HB_OT_LAYOUT_BASELINE_TAG_MATH: The baseline about which mathematical characters are centered.
* In vertical writing mode when mathematical characters rotated 90 degrees clockwise, are centered.
*
* Baseline tags from https://docs.microsoft.com/en-us/typography/opentype/spec/baselinetags
* Baseline tags from [Baseline Tags](https://docs.microsoft.com/en-us/typography/opentype/spec/baselinetags) registry.
*
* Since: 2.6.0
*/

15
src/hb-ot-tag.cc
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@ -164,6 +164,15 @@ hb_ot_all_tags_from_script (hb_script_t script,
*count = i;
}
/**
* hb_ot_tag_to_script:
* @tag: a script tag
*
* Converts a script tag to an #hb_script_t.
*
* Return value: The #hb_script_t corresponding to @tag.
*
**/
hb_script_t
hb_ot_tag_to_script (hb_tag_t tag)
{
@ -424,10 +433,12 @@ hb_ot_tags_from_script_and_language (hb_script_t script,
/**
* hb_ot_tag_to_language:
* @tag: an language tag
*
* Converts a language tag to an #hb_language_t.
*
*
* Return value: (transfer none):
* Return value: (transfer none) (nullable):
* The #hb_language_t corresponding to @tag.
*
* Since: 0.9.2
**/