stretch_box.rb

def stretch_box(ratio, point, options, &block)
  x, y = if ratio.is_a?(Array)
           ratio.map(&:to_f)
         else
           [ratio.to_f, 1.0]
         end
  options[:width] = options[:width] / x
  options[:height] = options[:height] / y if options.key?(:height)
  point[0] += bounds.absolute_left
  point[1] += bounds.absolute_bottom
  point[0] /= x
  point[1] /= y
  canvas do
    transformation_matrix(x, 0, 0, y, 0, 0) do
      bounding_box(point, options, &block)
    end
  end
end