anchor.diff:  
   /// Draw the image [src] onto the image [dst].
   ///
  -/// In other words, copyInto will take an rectangular area from src of
  +/// In other words, drawImage will take an rectangular area from src of
   /// width [src_w] and height [src_h] at position ([src_x],[src_y]) and place it
   /// in a rectangular area of [dst] of width [dst_w] and height [dst_h] at
   /// position ([dst_x],[dst_y]).
  
positive.code:   if (srcH == null) {
      srcH = src.height;
    }
  
    for (int y = 0; y < srcH; ++y) {
      for (int x = 0; x < srcW; ++x) {
        if (blend) {
          drawPixel(dst, dstX + x, dstY + y, src.getPixel(srcX + x, srcY + y));
        } else {
          dst.setPixel(dstX + x, dstY + y, src.getPixel(srcX + x, srcY + y));
        }
      }
    }
  
negative.code: /// The coordinates refer to the upper left corner. This function can be used to
  /// copy regions within the same image (if [dst] is the same as [src])
  /// but if the regions overlap the results will be unpredictable.
  Image drawImage(Image dst, Image src, {int dstX, int dstY, int dstW, int dstH,
    int srcX, int srcY, int srcW, int srcH, bool blend = true}) {
    if (dstX == null) {
      dstX = 0;
    }
  