class TTFunk::Table::Hmtx

Constants

HorizontalMetric

Attributes

left_side_bearings[R]
metrics[R]
widths[R]

Public Class Methods

encode(hmtx, mapping) click to toggle source
# File lib/ttfunk/table/hmtx.rb, line 12
def self.encode(hmtx, mapping)
  metrics =
    mapping.keys.sort.map do |new_id|
      metric = hmtx.for(mapping[new_id])
      [metric.advance_width, metric.left_side_bearing]
    end

  {
    number_of_metrics: metrics.length,
    table: metrics.flatten.pack('n*')
  }
end

Public Instance Methods

for(glyph_id) click to toggle source
# File lib/ttfunk/table/hmtx.rb, line 27
def for(glyph_id)
  @metrics[glyph_id] ||
    metrics_cache[glyph_id] ||=
      HorizontalMetric.new(
        @metrics.last.advance_width,
        @left_side_bearings[glyph_id - @metrics.length]
      )
end

Private Instance Methods

metrics_cache() click to toggle source
# File lib/ttfunk/table/hmtx.rb, line 38
def metrics_cache
  @metrics_cache ||= {}
end
parse!() click to toggle source
# File lib/ttfunk/table/hmtx.rb, line 42
def parse!
  @metrics = []

  file.horizontal_header.number_of_metrics.times do
    advance = read(2, 'n').first
    lsb = read_signed(1).first
    @metrics.push HorizontalMetric.new(advance, lsb)
  end

  lsb_count = file.maximum_profile.num_glyphs -
    file.horizontal_header.number_of_metrics
  @left_side_bearings = read_signed(lsb_count)

  @widths = @metrics.map(&:advance_width)
  @widths += [@widths.last] * @left_side_bearings.length
end