hb-ot-layout: HarfBuzz Manual

hb-ot-layout

hb-ot-layout — OpenType Layout

Functions

hb_language_t	hb_ot_tag_to_language ()
hb_script_t	hb_ot_tag_to_script ()
void	hb_ot_tags_from_script_and_language ()
void	hb_ot_tags_to_script_and_language ()
void	hb_ot_layout_collect_lookups ()
void	hb_ot_layout_collect_features ()
unsigned int	hb_ot_layout_feature_get_characters ()
unsigned int	hb_ot_layout_feature_get_lookups ()
hb_bool_t	hb_ot_layout_feature_get_name_ids ()
unsigned int	hb_ot_layout_feature_with_variations_get_lookups ()
unsigned int	hb_ot_layout_get_attach_points ()
hb_ot_layout_glyph_class_t	hb_ot_layout_get_glyph_class ()
void	hb_ot_layout_get_glyphs_in_class ()
unsigned int	hb_ot_layout_get_ligature_carets ()
hb_bool_t	hb_ot_layout_get_size_params ()
hb_bool_t	(*hb_ot_layout_glyph_sequence_func_t) ()
hb_bool_t	hb_ot_layout_has_glyph_classes ()
hb_bool_t	hb_ot_layout_has_positioning ()
hb_bool_t	hb_ot_layout_has_substitution ()
hb_bool_t	hb_ot_layout_language_find_feature ()
unsigned int	hb_ot_layout_language_get_feature_indexes ()
unsigned int	hb_ot_layout_language_get_feature_tags ()
hb_bool_t	hb_ot_layout_language_get_required_feature ()
void	hb_ot_layout_lookup_collect_glyphs ()
void	hb_ot_layout_lookup_substitute_closure ()
void	hb_ot_layout_lookups_substitute_closure ()
hb_bool_t	hb_ot_layout_lookup_would_substitute ()
unsigned int	hb_ot_layout_script_get_language_tags ()
hb_bool_t	hb_ot_layout_script_select_language ()
hb_bool_t	hb_ot_layout_table_find_feature_variations ()
unsigned int	hb_ot_layout_table_get_feature_tags ()
unsigned int	hb_ot_layout_table_get_script_tags ()
unsigned int	hb_ot_layout_table_get_lookup_count ()
hb_bool_t	hb_ot_layout_table_select_script ()
void	hb_ot_shape_plan_collect_lookups ()
hb_bool_t	hb_ot_layout_language_get_required_feature_index ()

Types and Values

#define	HB_OT_MAX_TAGS_PER_LANGUAGE
#define	HB_OT_MAX_TAGS_PER_SCRIPT
#define	HB_OT_TAG_DEFAULT_LANGUAGE
#define	HB_OT_TAG_DEFAULT_SCRIPT
#define	HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX
#define	HB_OT_LAYOUT_NO_FEATURE_INDEX
#define	HB_OT_LAYOUT_NO_SCRIPT_INDEX
#define	HB_OT_LAYOUT_NO_VARIATIONS_INDEX
#define	HB_OT_TAG_BASE
#define	HB_OT_TAG_GDEF
#define	HB_OT_TAG_GPOS
#define	HB_OT_TAG_GSUB
#define	HB_OT_TAG_JSTF
enum	hb_ot_layout_glyph_class_t

Object Hierarchy

    GEnum
    ╰── hb_ot_layout_glyph_class_t

Includes

#include <hb-ot.h>

Description

Functions for querying OpenType Layout features in the font face.

Functions

hb_ot_tag_to_language ()

hb_language_t
hb_ot_tag_to_language (hb_tag_t tag);

Returns

[transfer none]

Since: 0.9.2

hb_ot_tag_to_script ()

hb_script_t
hb_ot_tag_to_script (hb_tag_t tag);

hb_ot_tags_from_script_and_language ()

void
hb_ot_tags_from_script_and_language (hb_script_t script,
                                     hb_language_t language,
                                     unsigned int *script_count,
                                     hb_tag_t *script_tags,
                                     unsigned int *language_count,
                                     hb_tag_t *language_tags);

Converts an hb_script_t and an hb_language_t to script and language tags.

Parameters

script	an hb_script_t to convert.
language	an hb_language_t to convert.
script_count	maximum number of script tags to retrieve (IN) and actual number of script tags retrieved (OUT).	[allow-none]
script_tags	array of size at least `script_count` to store the script tag results.	[out][allow-none]
language_count	maximum number of language tags to retrieve (IN) and actual number of language tags retrieved (OUT).	[allow-none]
language_tags	array of size at least `language_count` to store the language tag results.	[out][allow-none]

Since: 2.0.0

hb_ot_tags_to_script_and_language ()

void
hb_ot_tags_to_script_and_language (hb_tag_t script_tag,
                                   hb_tag_t language_tag,
                                   hb_script_t *script,
                                   hb_language_t *language);

Converts a script tag and a language tag to an hb_script_t and an hb_language_t.

Parameters

script_tag	a script tag
language_tag	a language tag
script	the hb_script_t corresponding to `script_tag` (OUT).	[allow-none]
language	the hb_language_t corresponding to `script_tag` and `language_tag` (OUT).	[allow-none]

Since: 2.0.0

hb_ot_layout_collect_lookups ()

void
hb_ot_layout_collect_lookups (hb_face_t *face,
                              hb_tag_t table_tag,
                              const hb_tag_t *scripts,
                              const hb_tag_t *languages,
                              const hb_tag_t *features,
                              hb_set_t *lookup_indexes);

Since: 0.9.8

hb_ot_layout_collect_features ()

void
hb_ot_layout_collect_features (hb_face_t *face,
                               hb_tag_t table_tag,
                               const hb_tag_t *scripts,
                               const hb_tag_t *languages,
                               const hb_tag_t *features,
                               hb_set_t *feature_indexes);

Since: 1.8.5

hb_ot_layout_feature_get_characters ()

unsigned int
hb_ot_layout_feature_get_characters (hb_face_t *face,
                                     hb_tag_t table_tag,
                                     unsigned int feature_index,
                                     unsigned int start_offset,
                                     unsigned int *char_count,
                                     hb_codepoint_t *characters);

Fetches characters listed by designer under feature parameters for "Character Variant" ("cvXX") features.

Parameters

face	hb_face_t to work upon
table_tag	table tag to query, "GSUB" or "GPOS".
feature_index	index of feature to query.
start_offset	In case the resulting char_count was equal to its input value, there is a chance there were more characters on the tag so this API can be called with an offset till resulting char_count gets to a number lower than input buffer (or consider using just a bigger buffer for one shot copying).
char_count	The count of characters for which this feature provides glyph variants. (May be zero.).	[inout][allow-none]
characters	A buffer pointer. The Unicode codepoints of the characters for which this feature provides glyph variants.	[out caller-allocates][array length=char_count]

Returns

Number of total sample characters in the cvXX feature.

Since: 2.0.0

hb_ot_layout_feature_get_lookups ()

unsigned int
hb_ot_layout_feature_get_lookups (hb_face_t *face,
                                  hb_tag_t table_tag,
                                  unsigned int feature_index,
                                  unsigned int start_offset,
                                  unsigned int *lookup_count,
                                  unsigned int *lookup_indexes);

Since: 0.9.7

hb_ot_layout_feature_get_name_ids ()

hb_bool_t
hb_ot_layout_feature_get_name_ids (hb_face_t *face,
                                   hb_tag_t table_tag,
                                   unsigned int feature_index,
                                   hb_ot_name_id_t *label_id,
                                   hb_ot_name_id_t *tooltip_id,
                                   hb_ot_name_id_t *sample_id,
                                   unsigned int *num_named_parameters,
                                   hb_ot_name_id_t *first_param_id);

Fetches name indices from feature parameters for "Stylistic Set" ('ssXX') or "Character Variant" ('cvXX') features.

Parameters

face	hb_face_t to work upon
table_tag	table tag to query, "GSUB" or "GPOS".
feature_index	index of feature to query.
label_id	The ‘name’ table name ID that specifies a string for a user-interface label for this feature. (May be NULL.).	[out][allow-none]
tooltip_id	The ‘name’ table name ID that specifies a string that an application can use for tooltip text for this feature. (May be NULL.).	[out][allow-none]
sample_id	The ‘name’ table name ID that specifies sample text that illustrates the effect of this feature. (May be NULL.).	[out][allow-none]
num_named_parameters	Number of named parameters. (May be zero.).	[out][allow-none]
first_param_id	The first ‘name’ table name ID used to specify strings for user-interface labels for the feature parameters. (Must be zero if numParameters is zero.).	[out][allow-none]

Returns

true if data found, false otherwise

Since: 2.0.0

hb_ot_layout_feature_with_variations_get_lookups ()

unsigned int
hb_ot_layout_feature_with_variations_get_lookups
                               (hb_face_t *face,
                                hb_tag_t table_tag,
                                unsigned int feature_index,
                                unsigned int variations_index,
                                unsigned int start_offset,
                                unsigned int *lookup_count,
                                unsigned int *lookup_indexes);

hb_ot_layout_get_attach_points ()

unsigned int
hb_ot_layout_get_attach_points (hb_face_t *face,
                                hb_codepoint_t glyph,
                                unsigned int start_offset,
                                unsigned int *point_count,
                                unsigned int *point_array);

hb_ot_layout_get_glyph_class ()

hb_ot_layout_glyph_class_t
hb_ot_layout_get_glyph_class (hb_face_t *face,
                              hb_codepoint_t glyph);

Since: 0.9.7

hb_ot_layout_get_glyphs_in_class ()

void
hb_ot_layout_get_glyphs_in_class (hb_face_t *face,
                                  hb_ot_layout_glyph_class_t klass,
                                  hb_set_t *glyphs);

Since: 0.9.7

hb_ot_layout_get_ligature_carets ()

unsigned int
hb_ot_layout_get_ligature_carets (hb_font_t *font,
                                  hb_direction_t direction,
                                  hb_codepoint_t glyph,
                                  unsigned int start_offset,
                                  unsigned int *caret_count,
                                  hb_position_t *caret_array);

hb_ot_layout_get_size_params ()

hb_bool_t
hb_ot_layout_get_size_params (hb_face_t *face,
                              unsigned int *design_size,
                              unsigned int *subfamily_id,
                              hb_ot_name_id_t *subfamily_name_id,
                              unsigned int *range_start,
                              unsigned int *range_end);

Since: 0.9.10

hb_ot_layout_glyph_sequence_func_t ()

hb_bool_t
(*hb_ot_layout_glyph_sequence_func_t) (hb_font_t *font,
                                       hb_tag_t table_tag,
                                       unsigned int lookup_index,
                                       const hb_ot_layout_glyph_sequence_t *sequence,
                                       void *user_data);

hb_ot_layout_has_glyph_classes ()

hb_bool_t
hb_ot_layout_has_glyph_classes (hb_face_t *face);

hb_ot_layout_has_positioning ()

hb_bool_t
hb_ot_layout_has_positioning (hb_face_t *face);

hb_ot_layout_has_substitution ()

hb_bool_t
hb_ot_layout_has_substitution (hb_face_t *face);

hb_ot_layout_language_find_feature ()

hb_bool_t
hb_ot_layout_language_find_feature (hb_face_t *face,
                                    hb_tag_t table_tag,
                                    unsigned int script_index,
                                    unsigned int language_index,
                                    hb_tag_t feature_tag,
                                    unsigned int *feature_index);

hb_ot_layout_language_get_feature_indexes ()

unsigned int
hb_ot_layout_language_get_feature_indexes
                               (hb_face_t *face,
                                hb_tag_t table_tag,
                                unsigned int script_index,
                                unsigned int language_index,
                                unsigned int start_offset,
                                unsigned int *feature_count,
                                unsigned int *feature_indexes);

hb_ot_layout_language_get_feature_tags ()

unsigned int
hb_ot_layout_language_get_feature_tags
                               (hb_face_t *face,
                                hb_tag_t table_tag,
                                unsigned int script_index,
                                unsigned int language_index,
                                unsigned int start_offset,
                                unsigned int *feature_count,
                                hb_tag_t *feature_tags);

hb_ot_layout_language_get_required_feature ()

hb_bool_t
hb_ot_layout_language_get_required_feature
                               (hb_face_t *face,
                                hb_tag_t table_tag,
                                unsigned int script_index,
                                unsigned int language_index,
                                unsigned int *feature_index,
                                hb_tag_t *feature_tag);

Since: 0.9.30

hb_ot_layout_lookup_collect_glyphs ()

void
hb_ot_layout_lookup_collect_glyphs (hb_face_t *face,
                                    hb_tag_t table_tag,
                                    unsigned int lookup_index,
                                    hb_set_t *glyphs_before,
                                    hb_set_t *glyphs_input,
                                    hb_set_t *glyphs_after,
                                    hb_set_t *glyphs_output);

Since: 0.9.7

hb_ot_layout_lookup_substitute_closure ()

void
hb_ot_layout_lookup_substitute_closure
                               (hb_face_t *face,
                                unsigned int lookup_index,
                                hb_set_t *glyphs);

Since: 0.9.7

hb_ot_layout_lookups_substitute_closure ()

void
hb_ot_layout_lookups_substitute_closure
                               (hb_face_t *face,
                                const hb_set_t *lookups,
                                hb_set_t *glyphs);

Compute the transitive closure of glyphs needed for all of the provided lookups.

Since: 1.8.1

hb_ot_layout_lookup_would_substitute ()

hb_bool_t
hb_ot_layout_lookup_would_substitute (hb_face_t *face,
                                      unsigned int lookup_index,
                                      const hb_codepoint_t *glyphs,
                                      unsigned int glyphs_length,
                                      hb_bool_t zero_context);

Since: 0.9.7

hb_ot_layout_script_get_language_tags ()

unsigned int
hb_ot_layout_script_get_language_tags (hb_face_t *face,
                                       hb_tag_t table_tag,
                                       unsigned int script_index,
                                       unsigned int start_offset,
                                       unsigned int *language_count,
                                       hb_tag_t *language_tags);

hb_ot_layout_script_select_language ()

hb_bool_t
hb_ot_layout_script_select_language (hb_face_t *face,
                                     hb_tag_t table_tag,
                                     unsigned int script_index,
                                     unsigned int language_count,
                                     const hb_tag_t *language_tags,
                                     unsigned int *language_index);

Since: 2.0.0

hb_ot_layout_table_find_feature_variations ()

hb_bool_t
hb_ot_layout_table_find_feature_variations
                               (hb_face_t *face,
                                hb_tag_t table_tag,
                                const int *coords,
                                unsigned int num_coords,
                                unsigned int *variations_index);

hb_ot_layout_table_get_feature_tags ()

unsigned int
hb_ot_layout_table_get_feature_tags (hb_face_t *face,
                                     hb_tag_t table_tag,
                                     unsigned int start_offset,
                                     unsigned int *feature_count,
                                     hb_tag_t *feature_tags);

hb_ot_layout_table_get_script_tags ()

unsigned int
hb_ot_layout_table_get_script_tags (hb_face_t *face,
                                    hb_tag_t table_tag,
                                    unsigned int start_offset,
                                    unsigned int *script_count,
                                    hb_tag_t *script_tags);

hb_ot_layout_table_get_lookup_count ()

unsigned int
hb_ot_layout_table_get_lookup_count (hb_face_t *face,
                                     hb_tag_t table_tag);

Since: 0.9.22

hb_ot_layout_table_select_script ()

hb_bool_t
hb_ot_layout_table_select_script (hb_face_t *face,
                                  hb_tag_t table_tag,
                                  unsigned int script_count,
                                  const hb_tag_t *script_tags,
                                  unsigned int *script_index,
                                  hb_tag_t *chosen_script);

Since: 2.0.0

hb_ot_shape_plan_collect_lookups ()

void
hb_ot_shape_plan_collect_lookups (hb_shape_plan_t *shape_plan,
                                  hb_tag_t table_tag,
                                  hb_set_t *lookup_indexes);

Since: 0.9.7

hb_ot_layout_language_get_required_feature_index ()

hb_bool_t
hb_ot_layout_language_get_required_feature_index
                               (hb_face_t *face,
                                hb_tag_t table_tag,
                                unsigned int script_index,
                                unsigned int language_index,
                                unsigned int *feature_index);

Types and Values

HB_OT_MAX_TAGS_PER_LANGUAGE

#define HB_OT_MAX_TAGS_PER_LANGUAGE 3u

Since: 2.0.0

HB_OT_MAX_TAGS_PER_SCRIPT

#define HB_OT_MAX_TAGS_PER_SCRIPT 3u

Since: 2.0.0

HB_OT_TAG_DEFAULT_LANGUAGE

#define HB_OT_TAG_DEFAULT_LANGUAGE HB_TAG ('d', 'f', 'l', 't')

HB_OT_TAG_DEFAULT_SCRIPT

#define HB_OT_TAG_DEFAULT_SCRIPT HB_TAG ('D', 'F', 'L', 'T')

HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX

#define HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX 0xFFFFu

HB_OT_LAYOUT_NO_FEATURE_INDEX

#define HB_OT_LAYOUT_NO_FEATURE_INDEX		0xFFFFu

HB_OT_LAYOUT_NO_SCRIPT_INDEX

#define HB_OT_LAYOUT_NO_SCRIPT_INDEX		0xFFFFu

HB_OT_LAYOUT_NO_VARIATIONS_INDEX

#define HB_OT_LAYOUT_NO_VARIATIONS_INDEX 0xFFFFFFFFu

HB_OT_TAG_BASE

#define HB_OT_TAG_BASE HB_TAG('B','A','S','E')

HB_OT_TAG_GDEF

#define HB_OT_TAG_GDEF HB_TAG('G','D','E','F')

HB_OT_TAG_GPOS

#define HB_OT_TAG_GPOS HB_TAG('G','P','O','S')

HB_OT_TAG_GSUB

#define HB_OT_TAG_GSUB HB_TAG('G','S','U','B')

HB_OT_TAG_JSTF

#define HB_OT_TAG_JSTF HB_TAG('J','S','T','F')

enum hb_ot_layout_glyph_class_t

Members

HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED
HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH
HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE
HB_OT_LAYOUT_GLYPH_CLASS_MARK
HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT