Module: HarfBuzz::OT::Layout

Defined in:
lib/harfbuzz/ot/layout.rb

Overview

OpenType Layout table queries (GSUB/GPOS)

Class Method Summary collapse

Class Method Details

.attach_points(face, glyph) ⇒ Array<Integer>

Returns attachment point list for a glyph

Parameters:

  • face (Face) —

    Font face

  • glyph (Integer) —

    Glyph ID

Returns:

  • (Array<Integer>) —

    Attachment point indices



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# File 'lib/harfbuzz/ot/layout.rb', line 66

def attach_points(face, glyph)
  count_ptr = FFI::MemoryPointer.new(:uint)
  count_ptr.write_uint(0)
  total = C.hb_ot_layout_get_attach_points(face.ptr, glyph, 0, count_ptr, nil)
  return [] if total.zero?

  points_ptr = FFI::MemoryPointer.new(:uint, total)
  count_ptr.write_uint(total)
  C.hb_ot_layout_get_attach_points(face.ptr, glyph, 0, count_ptr, points_ptr)
  points_ptr.read_array_of_uint(count_ptr.read_uint)
end

.baseline(font, baseline_tag, dir, script_tag, language = nil) ⇒ Integer?

Returns a baseline coordinate value

Parameters:

  • font (Font) —

    Font

  • baseline_tag (Integer) —

    Baseline tag (HB_OT_LAYOUT_BASELINE_TAG_*)

  • dir (Symbol) —

    Direction (:ltr, :rtl, :ttb, :btt)

  • script_tag (Integer) —

    Script tag

  • language (FFI::Pointer, nil) (defaults to: nil) —

    Language pointer (nil = default)

Returns:

  • (Integer, nil) —

    Baseline coordinate or nil if not available



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# File 'lib/harfbuzz/ot/layout.rb', line 365

def baseline(font, baseline_tag, dir, script_tag, language = nil)
  lang_ptr = language || FFI::Pointer::NULL
  coord_ptr = FFI::MemoryPointer.new(:int32)
  found = C.from_hb_bool(
    C.hb_ot_layout_get_baseline(
      font.ptr, baseline_tag, dir, script_tag, lang_ptr, coord_ptr
    )
  )
  found ? coord_ptr.read_int32 : nil
end

.baseline2(font, baseline_tag, dir, script, language = nil) ⇒ Integer?

Returns a baseline coordinate value (v2: takes hb_script_t + hb_language_t)

Parameters:

  • font (Font) —

    Font

  • baseline_tag (Integer) —

    Baseline tag

  • dir (Symbol) —

    Direction

  • script (Integer) —

    Script value (hb_script_t, e.g. from HarfBuzz.script("Latn"))

  • language (FFI::Pointer, nil) (defaults to: nil) —

    Language pointer (nil = default)

Returns:

  • (Integer, nil) —

    Baseline coordinate or nil if not available



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# File 'lib/harfbuzz/ot/layout.rb', line 422

def baseline2(font, baseline_tag, dir, script, language = nil)
  lang_ptr = language || FFI::Pointer::NULL
  coord_ptr = FFI::MemoryPointer.new(:int32)
  found = C.from_hb_bool(
    C.hb_ot_layout_get_baseline2(
      font.ptr, baseline_tag, dir, script, lang_ptr, coord_ptr
    )
  )
  found ? coord_ptr.read_int32 : nil
end

.baseline_with_fallback(font, baseline_tag, dir, script_tag, language = nil) ⇒ Integer

Returns a baseline coordinate with fallback

Parameters:

  • font (Font) —

    Font

  • baseline_tag (Integer) —

    Baseline tag

  • dir (Symbol) —

    Direction

  • script_tag (Integer) —

    Script tag

  • language (FFI::Pointer, nil) (defaults to: nil) —

    Language pointer

Returns:

  • (Integer) —

    Baseline coordinate (with fallback)



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# File 'lib/harfbuzz/ot/layout.rb', line 383

def baseline_with_fallback(font, baseline_tag, dir, script_tag, language = nil)
  lang_ptr = language || FFI::Pointer::NULL
  coord_ptr = FFI::MemoryPointer.new(:int32)
  C.hb_ot_layout_get_baseline_with_fallback(
    font.ptr, baseline_tag, dir, script_tag, lang_ptr, coord_ptr
  )
  coord_ptr.read_int32
end

.baseline_with_fallback2(font, baseline_tag, dir, script, language = nil) ⇒ Integer

Returns a baseline coordinate with fallback (v2: takes hb_script_t + hb_language_t)

Parameters:

  • font (Font) —

    Font

  • baseline_tag (Integer) —

    Baseline tag

  • dir (Symbol) —

    Direction

  • script (Integer) —

    Script value (hb_script_t)

  • language (FFI::Pointer, nil) (defaults to: nil) —

    Language pointer

Returns:

  • (Integer) —

    Baseline coordinate (with fallback)



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# File 'lib/harfbuzz/ot/layout.rb', line 440

def baseline_with_fallback2(font, baseline_tag, dir, script, language = nil)
  lang_ptr = language || FFI::Pointer::NULL
  coord_ptr = FFI::MemoryPointer.new(:int32)
  C.hb_ot_layout_get_baseline_with_fallback2(
    font.ptr, baseline_tag, dir, script, lang_ptr, coord_ptr
  )
  coord_ptr.read_int32
end

.collect_features(face, table_tag, scripts: nil, languages: nil, features: nil) ⇒ HarfBuzz::Set

Collects all feature indices

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

Returns:



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# File 'lib/harfbuzz/ot/layout.rb', line 518

def collect_features(face, table_tag, scripts: nil, languages: nil, features: nil)
  set = HarfBuzz::Set.new
  scripts_ptr   = build_tag_array_ptr(scripts)
  languages_ptr = build_tag_array_ptr(languages)
  features_ptr  = build_tag_array_ptr(features)
  C.hb_ot_layout_collect_features(
    face.ptr, table_tag, scripts_ptr, languages_ptr, features_ptr, set.ptr
  )
  set
end

.collect_lookups(face, table_tag, scripts: nil, languages: nil, features: nil) ⇒ HarfBuzz::Set

Collects all lookups referenced by features

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • scripts (Array<Integer>, nil) (defaults to: nil) —

    Script tags filter (nil = all)

  • languages (Array<Integer>, nil) (defaults to: nil) —

    Language tags filter (nil = all)

  • features (Array<Integer>, nil) (defaults to: nil) —

    Feature tags filter (nil = all)

Returns:



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# File 'lib/harfbuzz/ot/layout.rb', line 503

def collect_lookups(face, table_tag, scripts: nil, languages: nil, features: nil)
  set = HarfBuzz::Set.new
  scripts_ptr  = build_tag_array_ptr(scripts)
  languages_ptr = build_tag_array_ptr(languages)
  features_ptr  = build_tag_array_ptr(features)
  C.hb_ot_layout_collect_lookups(
    face.ptr, table_tag, scripts_ptr, languages_ptr, features_ptr, set.ptr
  )
  set
end

.feature_characters(face, table_tag, feature_index) ⇒ Array<Integer>

Returns codepoints for a named feature's characters

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • feature_index (Integer) —

    Feature index

Returns:

  • (Array<Integer>) —

    Codepoints



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# File 'lib/harfbuzz/ot/layout.rb', line 342

def feature_characters(face, table_tag, feature_index)
  count_ptr = FFI::MemoryPointer.new(:uint)
  count_ptr.write_uint(0)
  total = C.hb_ot_layout_feature_get_characters(
    face.ptr, table_tag, feature_index, 0, count_ptr, nil
  )
  return [] if total.zero?

  cps_ptr = FFI::MemoryPointer.new(:uint32, total)
  count_ptr.write_uint(total)
  C.hb_ot_layout_feature_get_characters(
    face.ptr, table_tag, feature_index, 0, count_ptr, cps_ptr
  )
  cps_ptr.read_array_of_uint32(count_ptr.read_uint)
end

.feature_indexes(face, table_tag, script_index, language_index) ⇒ Array<Integer>

Returns feature indices for a language

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • script_index (Integer) —

    Script index

  • language_index (Integer) —

    Language index

Returns:

  • (Array<Integer>) —

    Feature indices



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# File 'lib/harfbuzz/ot/layout.rb', line 205

def feature_indexes(face, table_tag, script_index, language_index)
  count_ptr = FFI::MemoryPointer.new(:uint)
  count_ptr.write_uint(0)
  total = C.hb_ot_layout_language_get_feature_indexes(
    face.ptr, table_tag, script_index, language_index, 0, count_ptr, nil
  )
  return [] if total.zero?

  idx_ptr = FFI::MemoryPointer.new(:uint, total)
  count_ptr.write_uint(total)
  C.hb_ot_layout_language_get_feature_indexes(
    face.ptr, table_tag, script_index, language_index, 0, count_ptr, idx_ptr
  )
  idx_ptr.read_array_of_uint(count_ptr.read_uint)
end

.feature_lookups(face, table_tag, feature_index) ⇒ Array<Integer>

Returns lookup indices for a feature

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • feature_index (Integer) —

    Feature index

Returns:

  • (Array<Integer>) —

    Lookup indices



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# File 'lib/harfbuzz/ot/layout.rb', line 265

def feature_lookups(face, table_tag, feature_index)
  count_ptr = FFI::MemoryPointer.new(:uint)
  count_ptr.write_uint(0)
  total = C.hb_ot_layout_feature_get_lookups(
    face.ptr, table_tag, feature_index, 0, count_ptr, nil
  )
  return [] if total.zero?

  idx_ptr = FFI::MemoryPointer.new(:uint, total)
  count_ptr.write_uint(total)
  C.hb_ot_layout_feature_get_lookups(
    face.ptr, table_tag, feature_index, 0, count_ptr, idx_ptr
  )
  idx_ptr.read_array_of_uint(count_ptr.read_uint)
end

.feature_name_ids(face, table_tag, feature_index) ⇒ Hash?

Returns OpenType feature UI name IDs

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • feature_index (Integer) —

    Feature index

Returns:

  • (Hash, nil) —

    Name ID hash or nil



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# File 'lib/harfbuzz/ot/layout.rb', line 313

def feature_name_ids(face, table_tag, feature_index)
  label_id_ptr       = FFI::MemoryPointer.new(:uint)
  tooltip_id_ptr     = FFI::MemoryPointer.new(:uint)
  sample_id_ptr      = FFI::MemoryPointer.new(:uint)
  num_params_ptr     = FFI::MemoryPointer.new(:uint)
  first_param_id_ptr = FFI::MemoryPointer.new(:uint)
  found = C.from_hb_bool(
    C.hb_ot_layout_feature_get_name_ids(
      face.ptr, table_tag, feature_index,
      label_id_ptr, tooltip_id_ptr, sample_id_ptr,
      num_params_ptr, first_param_id_ptr
    )
  )
  return nil unless found

  {
    label_id: label_id_ptr.read_uint,
    tooltip_id: tooltip_id_ptr.read_uint,
    sample_id: sample_id_ptr.read_uint,
    num_named_parameters: num_params_ptr.read_uint,
    first_param_id: first_param_id_ptr.read_uint
  }
end

.feature_tags(face, table_tag) ⇒ Array<Integer>

Returns the feature tags for a table

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

Returns:

  • (Array<Integer>) —

    Feature tags



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# File 'lib/harfbuzz/ot/layout.rb', line 483

def feature_tags(face, table_tag)
  count_ptr = FFI::MemoryPointer.new(:uint)
  count_ptr.write_uint(0)
  C.hb_ot_layout_table_get_feature_tags(face.ptr, table_tag, 0, count_ptr, nil)
  count = count_ptr.read_uint
  return [] if count.zero?

  tags_ptr = FFI::MemoryPointer.new(:uint32, count)
  count_ptr.write_uint(count)
  C.hb_ot_layout_table_get_feature_tags(face.ptr, table_tag, 0, count_ptr, tags_ptr)
  tags_ptr.read_array_of_uint32(count_ptr.read_uint)
end

.feature_tags_for_lang(face, table_tag, script_index, language_index) ⇒ Array<Integer>

Returns feature tags for a language

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • script_index (Integer) —

    Script index

  • language_index (Integer) —

    Language index

Returns:

  • (Array<Integer>) —

    Feature tags



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# File 'lib/harfbuzz/ot/layout.rb', line 227

def feature_tags_for_lang(face, table_tag, script_index, language_index)
  count_ptr = FFI::MemoryPointer.new(:uint)
  count_ptr.write_uint(0)
  total = C.hb_ot_layout_language_get_feature_tags(
    face.ptr, table_tag, script_index, language_index, 0, count_ptr, nil
  )
  return [] if total.zero?

  tags_ptr = FFI::MemoryPointer.new(:uint32, total)
  count_ptr.write_uint(total)
  C.hb_ot_layout_language_get_feature_tags(
    face.ptr, table_tag, script_index, language_index, 0, count_ptr, tags_ptr
  )
  tags_ptr.read_array_of_uint32(count_ptr.read_uint)
end

.find_feature(face, table_tag, script_index, language_index, feature_tag) ⇒ Array

Finds a specific feature in a language, returns [found, feature_index]

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • script_index (Integer) —

    Script index

  • language_index (Integer) —

    Language index

  • feature_tag (Integer) —

    Feature tag to find

Returns:

  • (Array) —

    [Boolean, Integer] found and feature index



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# File 'lib/harfbuzz/ot/layout.rb', line 250

def find_feature(face, table_tag, script_index, language_index, feature_tag)
  idx_ptr = FFI::MemoryPointer.new(:uint)
  found = C.from_hb_bool(
    C.hb_ot_layout_language_find_feature(
      face.ptr, table_tag, script_index, language_index, feature_tag, idx_ptr
    )
  )
  [found, idx_ptr.read_uint]
end

.find_script(face, table_tag, script_tag) ⇒ Array

Finds a script in the table, returns [found, index]

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • script_tag (Integer) —

    Script tag to find

Returns:

  • (Array) —

    [Boolean, Integer] found and script index



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# File 'lib/harfbuzz/ot/layout.rb', line 100

def find_script(face, table_tag, script_tag)
  idx_ptr = FFI::MemoryPointer.new(:uint)
  found = C.from_hb_bool(
    C.hb_ot_layout_table_find_script(face.ptr, table_tag, script_tag, idx_ptr)
  )
  [found, idx_ptr.read_uint]
end

.font_extents(font, dir, script_tag, language = nil) ⇒ Hash?

Returns font extents from OT tables

Parameters:

  • font (Font) —

    Font

  • dir (Symbol) —

    Direction

  • script_tag (Integer) —

    Script tag

  • language (FFI::Pointer, nil) (defaults to: nil) —

    Language pointer

Returns:

  • (Hash, nil) —

    Font extents hash or nil



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# File 'lib/harfbuzz/ot/layout.rb', line 398

def font_extents(font, dir, script_tag, language = nil)
  lang_ptr = language || FFI::Pointer::NULL
  extents = C::HbFontExtentsT.new
  found = C.from_hb_bool(
    C.hb_ot_layout_get_font_extents(
      font.ptr, dir, script_tag, lang_ptr, extents.to_ptr
    )
  )
  return nil unless found

  {
    ascender: extents[:ascender],
    descender: extents[:descender],
    line_gap: extents[:line_gap]
  }
end

.font_extents2(font, dir, script, language = nil) ⇒ Hash?

Returns font extents from OT tables (v2: takes hb_script_t + hb_language_t)

Parameters:

  • font (Font) —

    Font

  • dir (Symbol) —

    Direction

  • script (Integer) —

    Script value (hb_script_t)

  • language (FFI::Pointer, nil) (defaults to: nil) —

    Language pointer

Returns:

  • (Hash, nil) —

    Font extents hash or nil



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# File 'lib/harfbuzz/ot/layout.rb', line 455

def font_extents2(font, dir, script, language = nil)
  lang_ptr = language || FFI::Pointer::NULL
  extents = C::HbFontExtentsT.new
  found = C.from_hb_bool(
    C.hb_ot_layout_get_font_extents2(
      font.ptr, dir, script, lang_ptr, extents.to_ptr
    )
  )
  return nil unless found

  {
    ascender: extents[:ascender],
    descender: extents[:descender],
    line_gap: extents[:line_gap]
  }
end

.glyph_class(face, glyph) ⇒ Symbol

Returns the glyph class from GDEF

Parameters:

  • face (Face) —

    Font face

  • glyph (Integer) —

    Glyph ID

Returns:

  • (Symbol) —

    Glyph class (:base_glyph, :ligature, :mark, :component)



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# File 'lib/harfbuzz/ot/layout.rb', line 31

def glyph_class(face, glyph)
  C.hb_ot_layout_get_glyph_class(face.ptr, glyph)
end

.glyphs_in_class(face, klass) ⇒ HarfBuzz::Set

Returns all glyphs in a given GDEF class

Parameters:

  • face (Face) —

    Font face

  • klass (Symbol) —

    Glyph class

Returns:



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# File 'lib/harfbuzz/ot/layout.rb', line 39

def glyphs_in_class(face, klass)
  set = HarfBuzz::Set.new
  C.hb_ot_layout_get_glyphs_in_class(face.ptr, klass, set.ptr)
  set
end

.has_glyph_classes?(face) ⇒ Boolean

Returns true if the face has GDEF glyph classes.

Parameters:

  • face (Face) —

    Font face

Returns:

  • (Boolean) —

    true if the face has GDEF glyph classes



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# File 'lib/harfbuzz/ot/layout.rb', line 11

def has_glyph_classes?(face)
  C.from_hb_bool(C.hb_ot_layout_has_glyph_classes(face.ptr))
end

.has_positioning?(face) ⇒ Boolean

Returns true if the face has a GPOS table.

Parameters:

  • face (Face) —

    Font face

Returns:

  • (Boolean) —

    true if the face has a GPOS table



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# File 'lib/harfbuzz/ot/layout.rb', line 23

def has_positioning?(face)
  C.from_hb_bool(C.hb_ot_layout_has_positioning(face.ptr))
end

.has_substitution?(face) ⇒ Boolean

Returns true if the face has a GSUB table.

Parameters:

  • face (Face) —

    Font face

Returns:

  • (Boolean) —

    true if the face has a GSUB table



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# File 'lib/harfbuzz/ot/layout.rb', line 17

def has_substitution?(face)
  C.from_hb_bool(C.hb_ot_layout_has_substitution(face.ptr))
end

.horizontal_baseline_tag_for_script(script) ⇒ Integer

Returns the horizontal baseline tag for a script

Parameters:

  • script (Integer) —

    Script value

Returns:

  • (Integer) —

    Baseline tag



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# File 'lib/harfbuzz/ot/layout.rb', line 475

def horizontal_baseline_tag_for_script(script)
  C.hb_ot_layout_get_horizontal_baseline_tag_for_script(script)
end

.language_tags(face, table_tag, script_index) ⇒ Array<Integer>

Returns language tags for a script

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • script_index (Integer) —

    Script index

Returns:

  • (Array<Integer>) —

    Language tags



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# File 'lib/harfbuzz/ot/layout.rb', line 131

def language_tags(face, table_tag, script_index)
  count_ptr = FFI::MemoryPointer.new(:uint)
  count_ptr.write_uint(0)
  total = C.hb_ot_layout_script_get_language_tags(
    face.ptr, table_tag, script_index, 0, count_ptr, nil
  )
  return [] if total.zero?

  tags_ptr = FFI::MemoryPointer.new(:uint32, total)
  count_ptr.write_uint(total)
  C.hb_ot_layout_script_get_language_tags(
    face.ptr, table_tag, script_index, 0, count_ptr, tags_ptr
  )
  tags_ptr.read_array_of_uint32(count_ptr.read_uint)
end

.ligature_carets(font, dir, glyph) ⇒ Array<Integer>

Returns ligature caret positions for a glyph

Parameters:

  • font (Font) —

    Font

  • dir (Symbol) —

    Direction (:ltr, :rtl)

  • glyph (Integer) —

    Glyph ID

Returns:

  • (Array<Integer>) —

    Caret positions



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# File 'lib/harfbuzz/ot/layout.rb', line 83

def ligature_carets(font, dir, glyph)
  count_ptr = FFI::MemoryPointer.new(:uint)
  count_ptr.write_uint(0)
  total = C.hb_ot_layout_get_ligature_carets(font.ptr, dir, glyph, 0, count_ptr, nil)
  return [] if total.zero?

  carets_ptr = FFI::MemoryPointer.new(:int32, total)
  count_ptr.write_uint(total)
  C.hb_ot_layout_get_ligature_carets(font.ptr, dir, glyph, 0, count_ptr, carets_ptr)
  carets_ptr.read_array_of_int32(count_ptr.read_uint)
end

.required_feature(face, table_tag, script_index, language_index) ⇒ Array?

Returns [feature_index, feature_tag] for the required feature, or nil

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • script_index (Integer) —

    Script index

  • language_index (Integer) —

    Language index

Returns:

  • (Array, nil) —

    [feature_index, feature_tag] or nil



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# File 'lib/harfbuzz/ot/layout.rb', line 188

def required_feature(face, table_tag, script_index, language_index)
  idx_ptr = FFI::MemoryPointer.new(:uint)
  tag_ptr = FFI::MemoryPointer.new(:uint32)
  found = C.from_hb_bool(
    C.hb_ot_layout_language_get_required_feature(
      face.ptr, table_tag, script_index, language_index, idx_ptr, tag_ptr
    )
  )
  found ? [idx_ptr.read_uint, tag_ptr.read_uint32] : nil
end

.required_feature_index(face, table_tag, script_index, language_index) ⇒ Integer?

Returns the required feature index for a language, or nil if none

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • script_index (Integer) —

    Script index

  • language_index (Integer) —

    Language index

Returns:

  • (Integer, nil) —

    Feature index or nil



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# File 'lib/harfbuzz/ot/layout.rb', line 172

def required_feature_index(face, table_tag, script_index, language_index)
  idx_ptr = FFI::MemoryPointer.new(:uint)
  found = C.from_hb_bool(
    C.hb_ot_layout_language_get_required_feature_index(
      face.ptr, table_tag, script_index, language_index, idx_ptr
    )
  )
  found ? idx_ptr.read_uint : nil
end

.script_tags(face, table_tag) ⇒ Array<Integer>

Returns the script tags for a table

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB (0x47535542) or GPOS (0x47504F53)

Returns:

  • (Array<Integer>) —

    Script tags



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# File 'lib/harfbuzz/ot/layout.rb', line 49

def script_tags(face, table_tag)
  count_ptr = FFI::MemoryPointer.new(:uint)
  count_ptr.write_uint(0)
  C.hb_ot_layout_table_get_script_tags(face.ptr, table_tag, 0, count_ptr, nil)
  count = count_ptr.read_uint
  return [] if count.zero?

  tags_ptr = FFI::MemoryPointer.new(:uint32, count)
  count_ptr.write_uint(count)
  C.hb_ot_layout_table_get_script_tags(face.ptr, table_tag, 0, count_ptr, tags_ptr)
  tags_ptr.read_array_of_uint32(count_ptr.read_uint)
end

.select_language(face, table_tag, script_index, language_tags) ⇒ Array

Selects the best matching language, returns [found, language_index]

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • script_index (Integer) —

    Script index

  • language_tags (Array<Integer>) —

    Candidate language tags

Returns:

  • (Array) —

    [Boolean, Integer] found and language index



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# File 'lib/harfbuzz/ot/layout.rb', line 153

def select_language(face, table_tag, script_index, language_tags)
  tags_ptr = FFI::MemoryPointer.new(:uint32, language_tags.size)
  tags_ptr.put_array_of_uint32(0, language_tags)
  lang_idx_ptr = FFI::MemoryPointer.new(:uint)
  found = C.from_hb_bool(
    C.hb_ot_layout_script_select_language(
      face.ptr, table_tag, script_index,
      language_tags.size, tags_ptr, lang_idx_ptr
    )
  )
  [found, lang_idx_ptr.read_uint]
end

.select_script(face, table_tag, script_tags) ⇒ Array

Selects the best matching script from a list

Parameters:

  • face (Face) —

    Font face

  • table_tag (Integer) —

    GSUB or GPOS tag

  • script_tags (Array<Integer>) —

    Candidate script tags (in preference order)

Returns:

  • (Array) —

    [Boolean, Integer, Integer] exact_match, script_index, chosen_script_tag



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# File 'lib/harfbuzz/ot/layout.rb', line 113

def select_script(face, table_tag, script_tags)
  tags_ptr = FFI::MemoryPointer.new(:uint32, script_tags.size)
  tags_ptr.put_array_of_uint32(0, script_tags)
  idx_ptr = FFI::MemoryPointer.new(:uint)
  chosen_tag_ptr = FFI::MemoryPointer.new(:uint32)
  exact = C.from_hb_bool(
    C.hb_ot_layout_table_select_script(
      face.ptr, table_tag, script_tags.size, tags_ptr, idx_ptr, chosen_tag_ptr
    )
  )
  [exact, idx_ptr.read_uint, chosen_tag_ptr.read_uint32]
end

.size_params(face) ⇒ Hash?

Returns size design parameters for the face

Parameters:

  • face (Face) —

    Font face

Returns:

  • (Hash, nil) —

    Size params hash or nil if not available



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# File 'lib/harfbuzz/ot/layout.rb', line 284

def size_params(face)
  design_size_ptr    = FFI::MemoryPointer.new(:uint)
  subfamily_id_ptr   = FFI::MemoryPointer.new(:uint)
  name_id_ptr        = FFI::MemoryPointer.new(:uint)
  range_start_ptr    = FFI::MemoryPointer.new(:uint)
  range_end_ptr      = FFI::MemoryPointer.new(:uint)
  found = C.from_hb_bool(
    C.hb_ot_layout_get_size_params(
      face.ptr,
      design_size_ptr, subfamily_id_ptr, name_id_ptr,
      range_start_ptr, range_end_ptr
    )
  )
  return nil unless found

  {
    design_size: design_size_ptr.read_uint,
    subfamily_id: subfamily_id_ptr.read_uint,
    subfamily_name_id: name_id_ptr.read_uint,
    range_start: range_start_ptr.read_uint,
    range_end: range_end_ptr.read_uint
  }
end

.tag_to_language(tag) ⇒ FFI::Pointer

Converts an OT tag to a language pointer

Parameters:

  • tag (Integer) —

    Language tag

Returns:

  • (FFI::Pointer) —

    Language pointer



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# File 'lib/harfbuzz/ot/layout.rb', line 561

def tag_to_language(tag)
  C.hb_ot_tag_to_language(tag)
end

.tag_to_script(tag) ⇒ Integer

Converts an OT tag to a script value

Parameters:

  • tag (Integer) —

    Script tag

Returns:

  • (Integer) —

    Script value



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# File 'lib/harfbuzz/ot/layout.rb', line 568

def tag_to_script(tag)
  C.hb_ot_tag_to_script(tag)
end

.tags_from_script_and_language(script, language) ⇒ Array<Array<Integer>>

Converts script+language to OT tags

Parameters:

  • script (Integer) —

    Script value

  • language (FFI::Pointer) —

    Language pointer

Returns:

  • (Array<Array<Integer>>) —

    [script_tags, language_tags]



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# File 'lib/harfbuzz/ot/layout.rb', line 533

def tags_from_script_and_language(script, language)
  s_count = FFI::MemoryPointer.new(:uint)
  l_count = FFI::MemoryPointer.new(:uint)
  s_count.write_uint(8)
  l_count.write_uint(8)
  s_tags = FFI::MemoryPointer.new(:uint32, 8)
  l_tags = FFI::MemoryPointer.new(:uint32, 8)
  C.hb_ot_tags_from_script_and_language(script, language, s_count, s_tags, l_count, l_tags)
  [
    s_tags.read_array_of_uint32(s_count.read_uint),
    l_tags.read_array_of_uint32(l_count.read_uint)
  ]
end

.tags_to_script_and_language(script_tag, language_tag) ⇒ Array

Converts OT tags to script + language

Parameters:

  • script_tag (Integer) —

    OT script tag

  • language_tag (Integer) —

    OT language tag

Returns:

  • (Array) —

    [script, language_ptr]



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# File 'lib/harfbuzz/ot/layout.rb', line 551

def tags_to_script_and_language(script_tag, language_tag)
  script_ptr = FFI::MemoryPointer.new(:uint32)
  lang_ptr = FFI::MemoryPointer.new(:pointer)
  C.hb_ot_tags_to_script_and_language(script_tag, language_tag, script_ptr, lang_ptr)
  [script_ptr.read_uint32, lang_ptr.read_pointer]
end