dispatchRect method

@override Uint8List dispatchRect(Uint8List data, int width, int height, Rect rect,)

Implementation

@override
Uint8List dispatchRect(Uint8List data, int width, int height, Rect rect) {
  final newByte = Uint8List.fromList(data);
  final emptyByte = Uint8List(rect.width * rect.height);
  final random = math.Random();
  int areaSize = 0;
  final step = random.nextDouble() * 2 + 1;

  int reductWidth, reductHeight = 0;

  for (double startH = rect.top.toDouble();
      startH < rect.bottom;
      startH += step) {
    reductHeight++;
    for (double startW = rect.left.toDouble();
        startW < rect.right;
        startW += step) {
      final index = (startH.toInt()) * width + startW.toInt();
      emptyByte[areaSize] = newByte[index];
      areaSize++;
    }
  }
  reductWidth = areaSize ~/ reductHeight;
  areaSize = 0;
  for (int startH = rect.top; startH < rect.bottom; startH++) {
    for (int startW = rect.left; startW < rect.right; startW++) {
      final index = startH * width + startW;
      final lefW = (rect.width - reductWidth) ~/ 2 + rect.left;
      final rigW = lefW + reductWidth;
      final topH = (rect.height - reductHeight) ~/ 2 + rect.top;
      final botH = topH + reductHeight;

      if (startH >= topH &&
          startH < botH &&
          startW >= lefW &&
          startW < rigW) {
        newByte[index] = emptyByte[areaSize++];
      } else {
        newByte[index] = 255;
      }
    }
  }
  return grayScaleDispatch.dispatch(newByte, width, height, rect);
}