# File lib/gd2/image.rb, line 753
    def merge_from(other, dst_x, dst_y, src_x, src_y, w, h, pct, gray = false)
      return super(other, dst_x, dst_y, src_x, src_y, w, h, pct) unless gray
      SYM[:gdImageCopyMergeGray].call(image_ptr, other.image_ptr,
        dst_x, dst_y, src_x, src_y, w, h, pct.to_percent.round)
      self
    end