require 'tempfile'

class Svg2Png < Nanoc::Filter
  identifier :svg2png
  type :binary
  def run(filename, params={})
    temp = Tempfile.new(File.basename(filename))
    raise Exception unless system("inkscape '--export-png=#{temp.path}' '#{filename}' >/dev/null")
    raise Exception unless system("convert '#{temp.path}' +dither -colors 256 '#{temp.path}'")
    raise Exception unless system("pngcrush -brute -q '#{temp.path}' '#{output_filename}'")
  end
end