# File lib/compass/sass_extensions/sprites/engines/chunky_png_engine.rb, line 12
        def construct_sprite
          @canvas = ChunkyPNG::Image.new(width, height, ChunkyPNG::Color::TRANSPARENT)
          images.each do |image|
            input_png  = ChunkyPNG::Image.from_file(image.file)
            if image.repeat == "no-repeat"
              canvas.replace! input_png, image.left, image.top
            else
              x = image.left - (image.left / image.width).ceil * image.width
              while x < width do
                begin
                  canvas.replace! input_png, x, image.top
                  x += image.width 
                rescue ChunkyPNG::OutOfBounds
                  break;
                end
              end
            end
          end
        end