def trim_rounded(src, trim, radius)
      trim_cc = Cairo::Context.new(Cairo::ImageSurface.new(@width - 2.0 * trim, @height - 2.0 * trim))
      trim_cc.rounded_rectangle(0, 0, trim_cc.target.width, trim_cc.target.height, radius, radius)
      trim_cc.set_source(src, -1 * trim, -1 * trim)
      trim_cc.clip
      trim_cc.paint
      return trim_cc.target
    end
def trim_rounded(src, trim, radius)
      trim_cc = Cairo::Context.new(Cairo::ImageSurface.new(@width - 2.0 * trim, @height - 2.0 * trim))
      trim_cc.rounded_rectangle(0, 0, trim_cc.target.width, trim_cc.target.height, radius, radius)
      trim_cc.set_source(src, -1 * trim, -1 * trim)
      trim_cc.clip
      trim_cc.paint
      return trim_cc.target
    end
:nodoc:
 @api private