Module harfbuzz

Lua bindings to Harfbuzz.

Info:

Functions

version () Wraps hb_version.
shape (font, buffer[, options]) Wraps hb_shape.

Class Blob

Blob.new (data) Wraps hb_blob_create.
Blob.new_from_file (filename) Wraps hb_blob_create_from_file.
Blob:get_length () Wraps hb_blob_get_length.
Blob:get_data () Wraps hb_blob_get_data.

Class Face

Face.new_from_blob (blob[, font_index=0]) Wraps hb_face_create.
Face.new (file[, font_index=0]) Create a new Face from a file.
Face:blob () Wraps hb_face_reference_blob.
Face:get_name (name_id[, lang]) Wraps hb_ot_name_get_utf8.
Face:collect_unicodes () Wraps hb_face_collect_unicodes.
Face:get_glyph_count () Wraps hb_face_get_glyph_count.
Face:get_table (tag) Wraps hb_face_reference_table.
Face:get_table_tags () Wraps hb_face_get_table_tags.
Face:get_upem () Wraps hb_face_get_upem.
Face:ot_color_has_palettes () Wraps hb_ot_color_has_palettes.
Face:ot_color_palette_get_count () Wraps hb_ot_color_palette_get_count.
Face:ot_color_palette_get_colors ([palette_index=1]) Wraps hb_ot_color_palette_get_colors.
Face:ot_color_has_layers () Wraps hb_ot_color_has_layers.
Face:ot_color_glyph_get_layers (glyph) Wraps hb_ot_color_glyph_get_layers.
Face:ot_color_has_png () Wraps hb_ot_color_has_png.
Face:ot_color_has_svg () Wraps hb_ot_color_has_svg.
Face:ot_color_glyph_get_svg (glyph) Wraps hb_ot_color_glyph_reference_svg.
Face:ot_var_has_data () Wraps hb_ot_var_has_data.
Face:ot_var_find_axis_info (tag) Wraps hb_ot_var_find_axis_info.
Face:ot_var_get_axis_infos ([start=1[, stop=-1]]) Wraps hb_ot_var_get_axis_infos.
Face:ot_var_named_instance_get_infos ([start=1[, stop=-1]]) Wraps hb_ot_var_get_named_instance_count and related functions.
Face:ot_var_named_instance_get_design_coords (index) Wraps hb_ot_var_named_instance_get_design_coords.
Face:ot_var_normalize_variations (...) Wraps hb_ot_var_normalize_variations.
Face:ot_var_normalize_coords (...) Wraps hb_ot_var_normalize_coords.
Face:ot_layout_get_script_tags (table_tag) Wraps hb_ot_layout_table_get_script_tags.
Face:ot_layout_get_language_tags (table_tag, script_index) Wraps hb_ot_layout_script_get_language_tags.
Face:ot_layout_get_feature_tags (table_tag, script_index, language_index) Wraps hb_ot_layout_language_get_feature_tags.
Face:ot_layout_find_script (table_tag, script_tag) Wraps hb_ot_layout_table_find_script.
Face:ot_layout_find_language (table_tag, script_index, language_tag) Wraps hb_ot_layout_script_find_language.
Face:ot_layout_find_feature (table_tag, script_index, language_index, feature_tag) Wraps hb_ot_layout_language_find_feature.

Class Font

Font.new (face) Wraps hb_font_create, and sets up some defaults for scale and shaping functions.
Font:get_scale () Wraps hb_font_get_scale.
Font:set_scale (x_scale, y_scale) Wraps hb_font_set_scale.
Font:get_h_extents () Wraps hb_font_get_h_extents.
Font:get_v_extents () Wraps hb_font_get_v_extents.
Font:get_glyph_extents (glyph) Wraps hb_font_get_glyph_extents.
Font:get_glyph_name (glyph) Wraps hb_font_get_glyph_name.
Font:get_glyph_from_name (name) Wraps hb_font_get_glyph_from_name.
Font:get_glyph_h_advance (glyph) Wraps hb_font_get_glyph_h_advance.
Font:get_glyph_v_advance (glyph) Wraps hb_font_get_glyph_v_advance.
Font:get_nominal_glyph (codepoint.) Wraps hb_font_get_nominal_glyph.
Font:style_get_value (tag) Wraps hb_style_get_value.
Font:ot_color_glyph_get_png (glyph) Wraps hb_ot_color_glyph_get_png.
Font:ot_metrics_get_position (tag) Wraps hb_ot_metrics_get_position.
Font:ot_metrics_get_variation (tag) Wraps hb_ot_metrics_get_variation.
Font:ot_metrics_get_x_variation (tag) Wraps hb_ot_metrics_get_x_variation.
Font:ot_metrics_get_y_variation (tag) Wraps hb_ot_metrics_get_y_variation.
Font:set_variations (...) Wraps hb_font_set_variations.
Font:set_var_coords_design (...) Wraps hb_font_set_var_coords_design.
Font:set_var_coords_normalized (...) Wraps hb_font_set_var_coords_normalized.
Font:set_var_named_instance (index) Wraps hb_font_set_var_named_instance.
Font:get_var_coords_normalized () Wraps hb_font_get_var_coords_normalized.

Class Buffer

Buffer.new () Wraps hb_buffer_create.
Buffer:add (codepoint, cluster) Wraps hb_buffer_add.
Buffer:add_utf8 (text[, item_offset=0[, item_length=-1]]) Wraps hb_buffer_add_utf8.
Buffer:add_codepoints (text[, item_offset=0[, item_length=-1]]) Wraps hb_buffer_add_codepoints.
Buffer:set_direction (dir) Wraps hb_buffer_set_direction.
Buffer:get_direction () Wraps hb_buffer_get_direction.
Buffer:set_script (script) Wraps hb_buffer_set_script.
Buffer:get_script () Wraps hb_buffer_get_script.
Buffer:set_language (lang) Wraps hb_buffer_set_language.
Buffer:get_language () Wraps hb_buffer_get_language.
Buffer:set_flags (flags) Wraps hb_buffer_set_flags.
Buffer:get_flags () Wraps hb_buffer_get_flags.
Buffer:set_cluster_level (level) Wraps hb_buffer_set_cluster_level.
Buffer:get_cluster_level () Wraps hb_buffer_get_cluster_level.
Buffer:set_invisible_glyph (glyph) Wraps hb_buffer_set_invisible_glyph.
Buffer:get_invisible_glyph () Wraps hb_buffer_get_invisible_glyph.
Buffer:set_replacement_codepoint (codepoint) Wraps hb_buffer_set_replacement_codepoint.
Buffer:get_replacement_codepoint () Wraps hb_buffer_get_replacement_codepoint.
Buffer:get_length () Wraps hb_buffer_get_length.
Buffer:guess_segment_properties () Wraps hb_buffer_guess_segment_properties.
Buffer:reverse () Wraps hb_buffer_reverse.
Buffer:clear_contents () Wraps hb_buffer_clear_contents.
Buffer:reset () Wraps hb_buffer_reset.
Buffer:pre_allocate (size) Wraps hb_buffer_pre_allocate.
Buffer:get_glyphs () Helper method to get shaped glyph data.

Cluster Levels

Buffer.CLUSTER_LEVEL_MONOTONE_GRAPHEMES Wraps HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES.
Buffer.CLUSTER_LEVEL_MONOTONE_CHARACTERS Wraps HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS.
Buffer.CLUSTER_LEVEL_CHARACTERS Wraps HB_BUFFER_CLUSTER_LEVEL_CHARACTERS.
Buffer.CLUSTER_LEVEL_DEFAULT Wraps HB_BUFFER_CLUSTER_LEVEL_DEFAULT.

Buffer Flags

Buffer.FLAG_DEFAULT Wraps HB_BUFFER_FLAG_DEFAULT.
Buffer.FLAG_BOT Wraps HB_BUFFER_FLAG_BOT.
Buffer.FLAG_EOT Wraps HB_BUFFER_FLAG_EOT.
Buffer.FLAG_PRESERVE_DEFAULT_IGNORABLES Wraps HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES.
Buffer.FLAG_REMOVE_DEFAULT_IGNORABLES Wraps HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES.
Buffer.FLAG_DO_NOT_INSERT_DOTTED_CIRCLE Wraps HB_BUFFER_FLAG_DO_NOT_INSERT_DOTTED_CIRCLE.
Buffer.FLAG_VERIFY Wraps HB_BUFFER_FLAG_VERIFY.
Buffer.FLAG_PRODUCE_UNSAFE_TO_CONCAT Wraps HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT.
Buffer.FLAG_PRODUCE_SAFE_TO_INSERT_TATWEEL Wraps HB_BUFFER_FLAG_PRODUCE_SAFE_TO_INSERT_TATWEEL.
Buffer.FLAG_DEFINED Wraps HB_BUFFER_FLAG_DEFINED.

Glyph Flags

Buffer.GLYPH_FLAG_UNSAFE_TO_BREAK Wraps HB_GLYPH_FLAG_UNSAFE_TO_BREAK.
Buffer.GLYPH_FLAG_UNSAFE_TO_CONCAT Wraps HB_GLYPH_FLAG_UNSAFE_TO_CONCAT.
Buffer.GLYPH_FLAG_SAFE_TO_INSERT_TATWEEL Wraps HB_GLYPH_FLAG_SAFE_TO_INSERT_TATWEEL.
Buffer.GLYPH_FLAG_DEFINED Wraps HB_GLYPH_FLAG_DEFINED.

Class Feature

Feature.new (feature_string) Wraps hb_feature_from_string
Feature:__tostring () Wraps hb_feature_to_string.

Class Variation

Variation.new (variation_string) Wraps hb_variation_from_string.
Variation:__tostring () Wraps hb_variation_to_string.

Class Tag

Tag.new (string) Wraps hb_tag_from_string.
Tag:__tostring () Wraps hb_tag_to_string.
Tag:__eq () Enables equality comparisions with == between two tags.

Class Script

Script.new (script) Wraps hb_script_from_string.
Script.from_iso15924_tag (tag) Wraps hb_script_from_iso15924_tag
Script:to_iso15924_tag () Wraps hb_script_to_iso15924_tag.
Script:__tostring () Enable nice output with tostring(…)
Script:__eq () Enables equality comparisions with == between two scripts.

Predefined Script Codes

Script.COMMON Wraps HB_SCRIPT_COMMON.
Script.INHERITED Wraps HB_SCRIPT_INHERITED.
Script.UNKNOWN Wraps HB_SCRIPT_UNKNOWN.
Script.INVALID Wraps HB_SCRIPT_INVALID.

Class Direction

Direction.new (dir) Wraps hb_direction_from_string.
Direction:__tostring () Wraps hb_direction_to_string.
Direction:__eq () Enables equality comparisions with == between two directions.
Direction:is_valid () Wraps HB_DIRECTION_IS_VALID.
Direction:is_horizontal () Wraps HB_DIRECTION_IS_HORIZONTAL.
Direction:is_vertical () Wraps HB_DIRECTION_IS_VERTICAL.
Direction:is_forward () Wraps HB_DIRECTION_IS_FORWARD.
Direction:is_backward () Wraps HB_DIRECTION_IS_BACKWARD.

Predefined directions

Direction.LTR Wraps HB_DIRECTION_LTR.
Direction.RTL Wraps HB_DIRECTION_RTL.
Direction.TTB Wraps HB_DIRECTION_TTB.
Direction.BTT Wraps HB_DIRECTION_LTR.

Class Language

Language.new (lang) Wraps hb_language_from_string.
Language:__tostring () Wraps hb_language_to_string.
Language:__eq () Enables equality comparisions with == between two languages.

Predefined languages

Language.INVALID Wraps HB_LANGUAGE_INVALID.

Class Set

Set:add (codepoint) Wraps hb_set_add.

Unicode functions

unicode.script (char) Wraps hb_unicode_script

Predefined Name IDs

ot.NAME_ID_COPYRIGHT Wraps HB_OT_NAME_ID_COPYRIGHT
ot.NAME_ID_FONT_FAMILY Wraps HB_OT_NAME_ID_FONT_FAMILY
ot.NAME_ID_FONT_SUBFAMILY Wraps HB_OT_NAME_ID_FONT_SUBFAMILY
ot.NAME_ID_UNIQUE_ID Wraps HB_OT_NAME_ID_UNIQUE_ID
ot.NAME_ID_FULL_NAME Wraps HB_OT_NAME_ID_FULL_NAME
ot.NAME_ID_VERSION_STRING Wraps HB_OT_NAME_ID_VERSION_STRING
ot.NAME_ID_POSTSCRIPT_NAME Wraps HB_OT_NAME_ID_POSTSCRIPT_NAME
ot.NAME_ID_TRADEMARK Wraps HB_OT_NAME_ID_TRADEMARK
ot.NAME_ID_MANUFACTURER Wraps HB_OT_NAME_ID_MANUFACTURER
ot.NAME_ID_DESIGNER Wraps HB_OT_NAME_ID_DESIGNER
ot.NAME_ID_DESCRIPTION Wraps HB_OT_NAME_ID_DESCRIPTION
ot.NAME_ID_VENDOR_URL Wraps HB_OT_NAME_ID_VENDOR_URL
ot.NAME_ID_DESIGNER_URL Wraps HB_OT_NAME_ID_DESIGNER_URL
ot.NAME_ID_LICENSE Wraps HB_OT_NAME_ID_LICENSE
ot.NAME_ID_LICENSE_URL Wraps HB_OT_NAME_ID_LICENSE_URL
ot.NAME_ID_TYPOGRAPHIC_FAMILY Wraps HB_OT_NAME_ID_TYPOGRAPHIC_FAMILY
ot.NAME_ID_TYPOGRAPHIC_SUBFAMILY Wraps HB_OT_NAME_ID_TYPOGRAPHIC_SUBFAMILY
ot.NAME_ID_MAC_FULL_NAME Wraps HB_OT_NAME_ID_MAC_FULL_NAME
ot.NAME_ID_SAMPLE_TEXT Wraps HB_OT_NAME_ID_SAMPLE_TEXT
ot.NAME_ID_CID_FINDFONT_NAME Wraps HB_OT_NAME_ID_CID_FINDFONT_NAME
ot.NAME_ID_WWS_FAMILY Wraps HB_OT_NAME_ID_WWS_FAMILY
ot.NAME_ID_WWS_SUBFAMILY Wraps HB_OT_NAME_ID_WWS_SUBFAMILY
ot.NAME_ID_LIGHT_BACKGROUND Wraps HB_OT_NAME_ID_LIGHT_BACKGROUND
ot.NAME_ID_DARK_BACKGROUND Wraps HB_OT_NAME_ID_DARK_BACKGROUND
ot.NAME_ID_VARIATIONS_PS_PREFIX Wraps HB_OT_NAME_ID_VARIATIONS_PS_PREFIX
ot.NAME_ID_INVALID Wraps HB_OT_NAME_ID_INVALID
ot.LAYOUT_NO_SCRIPT_INDEX Wraps HB_OT_LAYOUT_NO_SCRIPT_INDEX
ot.LAYOUT_NO_FEATURE_INDEX Wraps HB_OT_LAYOUT_NO_FEATURE_INDEX
ot.LAYOUT_DEFAULT_LANGUAGE_INDEX Wraps HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX
ot.LAYOUT_NO_VARIATIONS_INDEX Wraps HB_OT_LAYOUT_NO_VARIATIONS_INDEX


Functions

version ()
Wraps hb_version.
shape (font, buffer[, options])
Wraps hb_shape.

Parameters:

  • font Font to use for shaping
  • buffer Buffer to shape
  • options

    table containing one or more supported options:

    • direction: A Direction object representing the object.
    • script: A Script object representing the script.
    • language: A Language object representing the language.
    • features: features to enable, specified as either of the following.
    (optional)

Class Blob

Lua wrapper for hb_blob_t type. Wraps binary data such as font file contents or raw font table data.
Blob.new (data)
Wraps hb_blob_create. Initializes a new hb_blob_t.

Parameters:

  • data lua string containing binary or character data.

Returns:

    a Blob object holding the binary data.
Blob.new_from_file (filename)
Wraps hb_blob_create_from_file. Initializes a new hb_blob_t.

Parameters:

  • filename lua string.

Returns:

    a Blob object holding the file contents.
Blob:get_length ()
Wraps hb_blob_get_length.

Returns:

    length of the blob in bytes.
Blob:get_data ()
Wraps hb_blob_get_data.

Returns:

    blob contents as a string.

Class Face

Lua wrapper for hb_face_t type
Face.new_from_blob (blob[, font_index=0])
Wraps hb_face_create. Initializes a new hb_face_t from a Blob object.

Parameters:

  • blob Blob to read the font from.
  • font_index index of font to read. (default 0)

Returns:

    a Face object, or nil if the blob is invalid.
Face.new (file[, font_index=0])
Create a new Face from a file. Makes a call to Face:new_from_blob after creating a Blob from the file contents.

Parameters:

  • file path to font file.
  • font_index index of font to read. (default 0)

Returns:

    a Face object, or nil if the file cannot be read.
Face:blob ()
Wraps hb_face_reference_blob.

Returns:

    Blob containing the raw font data, or nil.
Face:get_name (name_id[, lang])
Wraps hb_ot_name_get_utf8.

Parameters:

  • name_id an ot.NAME_ID_* constant.
  • lang a Language object; uses default language if omitted. (optional)

Returns:

    name string, or nil if not found.
Face:collect_unicodes ()
Wraps hb_face_collect_unicodes.

Returns:

    table of codepoints supported by the face.
Face:get_glyph_count ()
Wraps hb_face_get_glyph_count.

Returns:

    number of glyphs in the face.
Face:get_table (tag)
Wraps hb_face_reference_table.

Parameters:

  • tag Tag object of the table.

Returns:

    Blob object for the face table of tag.
Face:get_table_tags ()
Wraps hb_face_get_table_tags.

Returns:

    table of Tags representing face table tags.
Face:get_upem ()
Wraps hb_face_get_upem.

Returns:

    units-per-em value of the face.
Face:ot_color_has_palettes ()
Wraps hb_ot_color_has_palettes.

Returns:

    boolean indicating whether the face has color palettes.
Face:ot_color_palette_get_count ()
Wraps hb_ot_color_palette_get_count.

Returns:

    number of color palettes in the face.
Face:ot_color_palette_get_colors ([palette_index=1])
Wraps hb_ot_color_palette_get_colors.

Parameters:

  • palette_index 1-indexed palette index. (default 1)

Returns:

    table of color tables each with red, green, blue, alpha fields, or nil.
Face:ot_color_has_layers ()
Wraps hb_ot_color_has_layers.

Returns:

    boolean indicating whether the face has layered color glyphs.
Face:ot_color_glyph_get_layers (glyph)
Wraps hb_ot_color_glyph_get_layers.

Parameters:

  • glyph glyph index.

Returns:

    table of layer tables each with glyph and color_index fields, or nil.
Face:ot_color_has_png ()
Wraps hb_ot_color_has_png.

Returns:

    boolean indicating whether the face has PNG color glyphs.
Face:ot_color_has_svg ()
Wraps hb_ot_color_has_svg.

Returns:

    boolean indicating whether the face has SVG color glyphs.
Face:ot_color_glyph_get_svg (glyph)
Wraps hb_ot_color_glyph_reference_svg.

Parameters:

  • glyph glyph index.

Returns:

    Blob containing the SVG data, or nil.
Face:ot_var_has_data ()
Wraps hb_ot_var_has_data.

Returns:

    boolean indicating whether the face has OpenType variation data.
Face:ot_var_find_axis_info (tag)
Wraps hb_ot_var_find_axis_info.

Parameters:

  • tag Tag of the variation axis.

Returns:

    table with fields axis_index, tag, name_id, flags, min_value, default_value, max_value, or nil if not found.
Face:ot_var_get_axis_infos ([start=1[, stop=-1]])
Wraps hb_ot_var_get_axis_infos.

Parameters:

  • start 1-indexed start axis. (default 1)
  • stop 1-indexed end axis (inclusive); -1 means last. (default -1)

Returns:

    table of axis info tables, each with fields axis_index, tag, name_id, flags, min_value, default_value, max_value.
Face:ot_var_named_instance_get_infos ([start=1[, stop=-1]])
Wraps hb_ot_var_get_named_instance_count and related functions.

Parameters:

  • start 1-indexed start instance. (default 1)
  • stop 1-indexed end instance (inclusive); -1 means last. (default -1)

Returns:

    table of instance info tables, each with fields index, subfamily_name_id, postscript_name_id.
Face:ot_var_named_instance_get_design_coords (index)
Wraps hb_ot_var_named_instance_get_design_coords.

Parameters:

  • index 1-indexed named instance index.

Returns:

    multiple return values, one number per axis.
Face:ot_var_normalize_variations (...)
Wraps hb_ot_var_normalize_variations.

Parameters:

  • ... one or more Variation objects.

Returns:

    multiple return values, one normalized integer coordinate per axis.
Face:ot_var_normalize_coords (...)
Wraps hb_ot_var_normalize_coords.

Parameters:

  • ... one or more design-space coordinate numbers, one per axis.

Returns:

    multiple return values, one normalized integer coordinate per axis.
Face:ot_layout_get_script_tags (table_tag)
Wraps hb_ot_layout_table_get_script_tags.

Parameters:

  • table_tag Tag for the layout table (GSUB or GPOS).

Returns:

    table of script Tags, or nil.
Face:ot_layout_get_language_tags (table_tag, script_index)
Wraps hb_ot_layout_script_get_language_tags.

Parameters:

  • table_tag Tag for the layout table (GSUB or GPOS).
  • script_index index of the script.

Returns:

    table of language Tags, or nil.
Face:ot_layout_get_feature_tags (table_tag, script_index, language_index)
Wraps hb_ot_layout_language_get_feature_tags.

Parameters:

  • table_tag Tag for the layout table (GSUB or GPOS).
  • script_index index of the script.
  • language_index index of the language.

Returns:

    table of feature Tags, or nil.
Face:ot_layout_find_script (table_tag, script_tag)
Wraps hb_ot_layout_table_find_script.

Parameters:

  • table_tag Tag for the layout table (GSUB or GPOS).
  • script_tag Tag of the script to find.

Returns:

    boolean indicating whether the script was found, and its index.
Face:ot_layout_find_language (table_tag, script_index, language_tag)
Wraps hb_ot_layout_script_find_language.

Parameters:

  • table_tag Tag for the layout table (GSUB or GPOS).
  • script_index index of the script.
  • language_tag Tag of the language to find.

Returns:

    boolean indicating whether the language was found, and its index.
Face:ot_layout_find_feature (table_tag, script_index, language_index, feature_tag)
Wraps hb_ot_layout_language_find_feature.

Parameters:

  • table_tag Tag for the layout table (GSUB or GPOS).
  • script_index index of the script.
  • language_index index of the language.
  • feature_tag Tag of the feature to find.

Returns:

    boolean indicating whether the feature was found, and its index.

Class Font

Lua wrapper for hb_font_t type
Font.new (face)
Wraps hb_font_create, and sets up some defaults for scale and shaping functions. Initializes a new hb_font_t from a Face object. Sets the default scale to the face’s upem value, and sets the font shaping functions by calling hb_ot_font_set_funcs on it.

Parameters:

  • face Face object.

Returns:

    a Font object.
Font:get_scale ()
Wraps hb_font_get_scale.

Returns:

    two values for the x-scale and y-scale of the font.
Font:set_scale (x_scale, y_scale)
Wraps hb_font_set_scale.

Parameters:

  • x_scale desired x-scale of font.
  • y_scale desired y-scale of font.
Font:get_h_extents ()
Wraps hb_font_get_h_extents.

Returns:

    font extents table for horizontal direction, contains the following or nil if HarfBuzz fails to load font extents:

    • ascender: typographic ascender.
    • descender: typographic descender.
    • line_gap: line spacing gap.
Font:get_v_extents ()
Wraps hb_font_get_v_extents.

Returns:

    font extents table for vertical direction, similar to Font:get_h_extents, or nil if HarfBuzz fails to load font extents:
Font:get_glyph_extents (glyph)
Wraps hb_font_get_glyph_extents.

Parameters:

  • glyph index inside the font.

Returns:

    extents table contains the following or nil if HarfBuzz fails to load glyph extents:

    • x_bearing: left side of glyph from origin.
    • y_bearing: top side of glyph from origin.
    • width: distance from left to right side.
    • height: distance from top to bottom side.
Font:get_glyph_name (glyph)
Wraps hb_font_get_glyph_name.

Parameters:

  • glyph index inside the font.

Returns:

    name of the glyph or nil.
Font:get_glyph_from_name (name)
Wraps hb_font_get_glyph_from_name.

Parameters:

  • name of the glyph.

Returns:

    glyph index inside the font or nil.
Font:get_glyph_h_advance (glyph)
Wraps hb_font_get_glyph_h_advance.

Parameters:

  • glyph index inside the font.

Returns:

    advance glyph advance of the glyph in horizontal direction.
Font:get_glyph_v_advance (glyph)
Wraps hb_font_get_glyph_v_advance.

Parameters:

  • glyph index inside the font.

Returns:

    advance glyph advance of the glyph in vertical direction.
Font:get_nominal_glyph (codepoint.)
Wraps hb_font_get_nominal_glyph.

Parameters:

  • codepoint.

Returns:

    glyph index or nil if codepoint is not supported by the font.
Font:style_get_value (tag)
Wraps hb_style_get_value. Available when HarfBuzz >= 3.

Parameters:

  • tag a Tag object for the style axis (e.g. wght, ital).

Returns:

    style value as a number.
Font:ot_color_glyph_get_png (glyph)
Wraps hb_ot_color_glyph_get_png.

Parameters:

  • glyph glyph index.

Returns:

    Blob containing the PNG data, or nil.
Font:ot_metrics_get_position (tag)
Wraps hb_ot_metrics_get_position.

Parameters:

  • tag a Tag object for the metric.

Returns:

    integer position value, or nil if not available.
Font:ot_metrics_get_variation (tag)
Wraps hb_ot_metrics_get_variation.

Parameters:

  • tag a Tag object for the metric.

Returns:

    number variation value.
Font:ot_metrics_get_x_variation (tag)
Wraps hb_ot_metrics_get_x_variation.

Parameters:

  • tag a Tag object for the metric.

Returns:

    integer x variation value.
Font:ot_metrics_get_y_variation (tag)
Wraps hb_ot_metrics_get_y_variation.

Parameters:

  • tag a Tag object for the metric.

Returns:

    integer y variation value.
Font:set_variations (...)
Wraps hb_font_set_variations.

Parameters:

  • ... one or more Variation objects.
Font:set_var_coords_design (...)
Wraps hb_font_set_var_coords_design.

Parameters:

  • ... one or more design-space coordinate numbers, one per axis.
Font:set_var_coords_normalized (...)
Wraps hb_font_set_var_coords_normalized.

Parameters:

  • ... one or more normalized coordinate integers, one per axis.
Font:set_var_named_instance (index)
Wraps hb_font_set_var_named_instance.

Parameters:

  • index 1-indexed named instance index.
Font:get_var_coords_normalized ()
Wraps hb_font_get_var_coords_normalized.

Returns:

    multiple return values, one normalized integer coordinate per axis.

Class Buffer

Lua wrapper for hb_buffer_t type.
Buffer.new ()
Wraps hb_buffer_create.

Returns:

    a Buffer object.
Buffer:add (codepoint, cluster)
Wraps hb_buffer_add.

Parameters:

  • codepoint Unicode codepoint to add.
  • cluster cluster index of the codepoint.
Buffer:add_utf8 (text[, item_offset=0[, item_length=-1]])
Wraps hb_buffer_add_utf8.

Parameters:

  • text UTF8 encoded string.
  • item_offset 0-indexed offset in text, from where to start adding. (default 0)
  • item_length length to add from item_offset. -1 adds till end of text. (default -1)
Buffer:add_codepoints (text[, item_offset=0[, item_length=-1]])
Wraps hb_buffer_add_codepoints.

Parameters:

  • text table with codepoints as lua numbers.
  • item_offset 0-indexed offset in text, from where to start adding. (default 0)
  • item_length length to add from item_offset. -1 adds till end of text. (default -1)
Buffer:set_direction (dir)
Wraps hb_buffer_set_direction.

Parameters:

  • dir A Direction object.
Buffer:get_direction ()
Wraps hb_buffer_get_direction.

Returns:

    A Direction object.
Buffer:set_script (script)
Wraps hb_buffer_set_script.

Parameters:

  • script A Script object.
Buffer:get_script ()
Wraps hb_buffer_get_script.

Returns:

    A Script object.
Buffer:set_language (lang)
Wraps hb_buffer_set_language.

Parameters:

  • lang A Language object
Buffer:get_language ()
Wraps hb_buffer_get_language.

Returns:

    A Language object
Buffer:set_flags (flags)
Wraps hb_buffer_set_flags.

Parameters:

Buffer:get_flags ()
Wraps hb_buffer_get_flags.

Returns:

    see Buffer Flags
Buffer:set_cluster_level (level)
Wraps hb_buffer_set_cluster_level.

Parameters:

Buffer:get_cluster_level ()
Wraps hb_buffer_get_cluster_level.

Returns:

    see Cluster Levels
Buffer:set_invisible_glyph (glyph)
Wraps hb_buffer_set_invisible_glyph.

Parameters:

  • glyph glyph index to use for invisible characters.
Buffer:get_invisible_glyph ()
Wraps hb_buffer_get_invisible_glyph.

Returns:

    glyph index used for invisible characters.
Buffer:set_replacement_codepoint (codepoint)
Wraps hb_buffer_set_replacement_codepoint.

Parameters:

  • codepoint replacement codepoint for invalid input.
Buffer:get_replacement_codepoint ()
Wraps hb_buffer_get_replacement_codepoint.

Returns:

    replacement codepoint for invalid input.
Buffer:get_length ()
Wraps hb_buffer_get_length.

Returns:

    number of items in the buffer.
Buffer:guess_segment_properties ()
Wraps hb_buffer_guess_segment_properties.
Buffer:reverse ()
Wraps hb_buffer_reverse.
Buffer:clear_contents ()
Wraps hb_buffer_clear_contents.
Buffer:reset ()
Wraps hb_buffer_reset.
Buffer:pre_allocate (size)
Wraps hb_buffer_pre_allocate.

Parameters:

  • size number of items to pre-allocate.

Returns:

    boolean indicating success.
Buffer:get_glyphs ()
Helper method to get shaped glyph data. Calls hb_buffer_get_glyph_infos, hb_buffer_get_glyph_positions and hb_glyph_info_get_glyph_flags, and assembles the data into a Lua table.

Returns:

    table containing data for each glyph, in a nested table. Each nested table contains the following:

    • x_advance: horizontal advance.
    • y_advance: vertical advance.
    • x_offset: horizontal displacement.
    • y_offset: vertical displacement.
    • cluster: glyph cluster index within input.
    • codepoint: glyph index inside the font (this field name is a bit misleading, but that’s what Harfbuzz uses).
    • flags: glyph flags

Cluster Levels

See Harfbuzz docs for more details about what each of these levels mean.
Buffer.CLUSTER_LEVEL_MONOTONE_GRAPHEMES
Wraps HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES.
Buffer.CLUSTER_LEVEL_MONOTONE_CHARACTERS
Wraps HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS.
Buffer.CLUSTER_LEVEL_CHARACTERS
Wraps HB_BUFFER_CLUSTER_LEVEL_CHARACTERS.
Buffer.CLUSTER_LEVEL_DEFAULT
Wraps HB_BUFFER_CLUSTER_LEVEL_DEFAULT.

Buffer Flags

See Harfbuzz docs for more details about what each of these flags mean.
Buffer.FLAG_DEFAULT
Wraps HB_BUFFER_FLAG_DEFAULT.
Buffer.FLAG_BOT
Wraps HB_BUFFER_FLAG_BOT.
Buffer.FLAG_EOT
Wraps HB_BUFFER_FLAG_EOT.
Buffer.FLAG_PRESERVE_DEFAULT_IGNORABLES
Wraps HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES.
Buffer.FLAG_REMOVE_DEFAULT_IGNORABLES
Wraps HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES.
Buffer.FLAG_DO_NOT_INSERT_DOTTED_CIRCLE
Wraps HB_BUFFER_FLAG_DO_NOT_INSERT_DOTTED_CIRCLE.
Buffer.FLAG_VERIFY
Wraps HB_BUFFER_FLAG_VERIFY.
Buffer.FLAG_PRODUCE_UNSAFE_TO_CONCAT
Wraps HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT.
Buffer.FLAG_PRODUCE_SAFE_TO_INSERT_TATWEEL
Wraps HB_BUFFER_FLAG_PRODUCE_SAFE_TO_INSERT_TATWEEL.
Buffer.FLAG_DEFINED
Wraps HB_BUFFER_FLAG_DEFINED.

Glyph Flags

See Harfbuzz docs for more details about what each of these flags mean.
Buffer.GLYPH_FLAG_UNSAFE_TO_BREAK
Wraps HB_GLYPH_FLAG_UNSAFE_TO_BREAK.
Buffer.GLYPH_FLAG_UNSAFE_TO_CONCAT
Wraps HB_GLYPH_FLAG_UNSAFE_TO_CONCAT.
Buffer.GLYPH_FLAG_SAFE_TO_INSERT_TATWEEL
Wraps HB_GLYPH_FLAG_SAFE_TO_INSERT_TATWEEL.
Buffer.GLYPH_FLAG_DEFINED
Wraps HB_GLYPH_FLAG_DEFINED.

Class Feature

Lua wrapper for hb_feature_t type
Feature.new (feature_string)
Wraps hb_feature_from_string

Parameters:

Feature:__tostring ()
Wraps hb_feature_to_string. Enables nice output with tostring(…).

Class Variation

Lua wrapper for hb_variation_t type.
Variation.new (variation_string)
Wraps hb_variation_from_string.

Parameters:

  • variation_string variation string, e.g. "wght=700".

Returns:

    a Variation object, or nil if the string is invalid.
Variation:__tostring ()
Wraps hb_variation_to_string. Enables nice output with tostring(…).

Class Tag

Lua wrapper for hb_tag_t type.
Tag.new (string)
Wraps hb_tag_from_string.

Parameters:

  • string to be converted to a Tag object.

Returns:

    a Tag object.
Tag:__tostring ()
Wraps hb_tag_to_string. Enable nice output with tostring(…).

Returns:

    Returns a string representation for the tag object.
Tag:__eq ()
Enables equality comparisions with == between two tags.

Returns:

    true or false depending on whether the two tags are equal.

Class Script

Lua wrapper for hb_script_t type.
Script.new (script)
Wraps hb_script_from_string.

Parameters:

Returns:

    a Script object.
Script.from_iso15924_tag (tag)
Wraps hb_script_from_iso15924_tag

Parameters:

Script:to_iso15924_tag ()
Wraps hb_script_to_iso15924_tag.

Returns:

    a Tag object representing the script.
Script:__tostring ()
Enable nice output with tostring(…)

Returns:

    Returns a 4-letter ISO 15924 script code for the script object.
Script:__eq ()
Enables equality comparisions with == between two scripts.

Returns:

    true or false depending on whether the two scripts are equal.

Predefined Script Codes

Predefined directions that correspond to their original definitions in Harfbuzz.
Script.COMMON
Wraps HB_SCRIPT_COMMON.
Script.INHERITED
Wraps HB_SCRIPT_INHERITED.
Script.UNKNOWN
Wraps HB_SCRIPT_UNKNOWN.
Script.INVALID
Wraps HB_SCRIPT_INVALID.

Class Direction

Lua wrapper for hb_direction_t type.
Direction.new (dir)
Wraps hb_direction_from_string.

Parameters:

  • dir can be one of ltr, rtl, ttb, btt or invalid.

Returns:

    a Direction object.
Direction:__tostring ()
Wraps hb_direction_to_string. Enable nice output with tostring(…).

Returns:

    Returns a string representation for direction.
Direction:__eq ()
Enables equality comparisions with == between two directions.

Returns:

    true or false depending on whether the two tags are equal.
Direction:is_valid ()
Wraps HB_DIRECTION_IS_VALID.

Returns:

    a boolean value
Direction:is_horizontal ()
Wraps HB_DIRECTION_IS_HORIZONTAL.

Returns:

    a boolean value
Direction:is_vertical ()
Wraps HB_DIRECTION_IS_VERTICAL.

Returns:

    a boolean value
Direction:is_forward ()
Wraps HB_DIRECTION_IS_FORWARD.

Returns:

    a boolean value
Direction:is_backward ()
Wraps HB_DIRECTION_IS_BACKWARD.

Returns:

    a boolean value

Predefined directions

Predefined directions that correspond to their original definitions in Harfbuzz.
Direction.LTR
Wraps HB_DIRECTION_LTR.
Direction.RTL
Wraps HB_DIRECTION_RTL.
Direction.TTB
Wraps HB_DIRECTION_TTB.
Direction.BTT
Wraps HB_DIRECTION_LTR.

Class Language

Lua wrapper for hb_language_t type.
Language.new (lang)
Wraps hb_language_from_string.

Parameters:

Returns:

    a Language object.
Language:__tostring ()
Wraps hb_language_to_string. Enable nice output with tostring(…).

Returns:

    Returns a string representation for the language object.
Language:__eq ()
Enables equality comparisions with == between two languages.

Returns:

    true or false depending on whether the two languages are equal.

Predefined languages

Predefined languages that correspond to their original definitions in Harfbuzz.
Language.INVALID
Wraps HB_LANGUAGE_INVALID.

Class Set

Lua wrapper for hb_set_t type.

Set objects represent a mathematical set of integer values.

Set:add (codepoint)
Wraps hb_set_add.

Adds a codepoint to the set.

Parameters:

  • codepoint The element to add.

Unicode functions

unicode.script (char)
Wraps hb_unicode_script

Parameters:

  • char Unicode codepoint

Returns:

    a Script object.

Predefined Name IDs

Predefined OpenType 'name' table name identifier.
ot.NAME_ID_COPYRIGHT
Wraps HB_OT_NAME_ID_COPYRIGHT
ot.NAME_ID_FONT_FAMILY
Wraps HB_OT_NAME_ID_FONT_FAMILY
ot.NAME_ID_FONT_SUBFAMILY
Wraps HB_OT_NAME_ID_FONT_SUBFAMILY
ot.NAME_ID_UNIQUE_ID
Wraps HB_OT_NAME_ID_UNIQUE_ID
ot.NAME_ID_FULL_NAME
Wraps HB_OT_NAME_ID_FULL_NAME
ot.NAME_ID_VERSION_STRING
Wraps HB_OT_NAME_ID_VERSION_STRING
ot.NAME_ID_POSTSCRIPT_NAME
Wraps HB_OT_NAME_ID_POSTSCRIPT_NAME
ot.NAME_ID_TRADEMARK
Wraps HB_OT_NAME_ID_TRADEMARK
ot.NAME_ID_MANUFACTURER
Wraps HB_OT_NAME_ID_MANUFACTURER
ot.NAME_ID_DESIGNER
Wraps HB_OT_NAME_ID_DESIGNER
ot.NAME_ID_DESCRIPTION
Wraps HB_OT_NAME_ID_DESCRIPTION
ot.NAME_ID_VENDOR_URL
Wraps HB_OT_NAME_ID_VENDOR_URL
ot.NAME_ID_DESIGNER_URL
Wraps HB_OT_NAME_ID_DESIGNER_URL
ot.NAME_ID_LICENSE
Wraps HB_OT_NAME_ID_LICENSE
ot.NAME_ID_LICENSE_URL
Wraps HB_OT_NAME_ID_LICENSE_URL
ot.NAME_ID_TYPOGRAPHIC_FAMILY
Wraps HB_OT_NAME_ID_TYPOGRAPHIC_FAMILY
ot.NAME_ID_TYPOGRAPHIC_SUBFAMILY
Wraps HB_OT_NAME_ID_TYPOGRAPHIC_SUBFAMILY
ot.NAME_ID_MAC_FULL_NAME
Wraps HB_OT_NAME_ID_MAC_FULL_NAME
ot.NAME_ID_SAMPLE_TEXT
Wraps HB_OT_NAME_ID_SAMPLE_TEXT
ot.NAME_ID_CID_FINDFONT_NAME
Wraps HB_OT_NAME_ID_CID_FINDFONT_NAME
ot.NAME_ID_WWS_FAMILY
Wraps HB_OT_NAME_ID_WWS_FAMILY
ot.NAME_ID_WWS_SUBFAMILY
Wraps HB_OT_NAME_ID_WWS_SUBFAMILY
ot.NAME_ID_LIGHT_BACKGROUND
Wraps HB_OT_NAME_ID_LIGHT_BACKGROUND
ot.NAME_ID_DARK_BACKGROUND
Wraps HB_OT_NAME_ID_DARK_BACKGROUND
ot.NAME_ID_VARIATIONS_PS_PREFIX
Wraps HB_OT_NAME_ID_VARIATIONS_PS_PREFIX
ot.NAME_ID_INVALID
Wraps HB_OT_NAME_ID_INVALID
ot.LAYOUT_NO_SCRIPT_INDEX
Wraps HB_OT_LAYOUT_NO_SCRIPT_INDEX
ot.LAYOUT_NO_FEATURE_INDEX
Wraps HB_OT_LAYOUT_NO_FEATURE_INDEX
ot.LAYOUT_DEFAULT_LANGUAGE_INDEX
Wraps HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX
ot.LAYOUT_NO_VARIATIONS_INDEX
Wraps HB_OT_LAYOUT_NO_VARIATIONS_INDEX
generated by LDoc 1.5.0 Last updated 2026-06-23 14:19:38