Module: Fontisan::Ufo::Compile::Avar

Defined in:
lib/fontisan/ufo/compile/avar.rb

Overview

Builds the OpenType avar (Axis Variation) table.

avar defines non-linear interpolation curves for each axis. For axes with linear interpolation (the common case), each axis gets 3 default maps: (-1→-1, 0→0, 1→1).

See Also:

Class Method Summary collapse

Class Method Details

.build(axes:) ⇒ String

Returns avar table bytes.

Parameters:

  • axes (Array<Hash>) —

    axis definitions (tag + optional maps)

Returns:

  • (String) —

    avar table bytes



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# File 'lib/fontisan/ufo/compile/avar.rb', line 16

def self.build(axes:)
  return nil if axes.nil? || axes.empty?

  io = +""
  io << [0x00010000].pack("N") # version 1.0
  io << [0].pack("n")          # reserved
  io << [axes.size].pack("n")  # axisCount

  axes.each do |axis|
    maps = axis[:maps] || default_maps
    io << [maps.size].pack("n")
    maps.each do |from, to|
      io << [f2dot14(from), f2dot14(to)].pack("nn")
    end
  end

  io
end