pack method

@override Uint8List pack()

Corresponding parser should be called from frame_app data handler

Implementation

@override
Uint8List pack() {
  if (_spriteLines.isEmpty) {
    throw Exception('_spriteLines is empty: no image to pack()');
  }

  // pack the width and height of the image (Uint16 each)
  int widthMsb = width >> 8;
  int widthLsb = width & 0xFF;
  int heightMsb = height >> 8;
  int heightLsb = height & 0xFF;

  // store the spriteLineHeight (Uint16)
  int spriteLineHeightMsb = spriteLineHeight >> 8;
  int spriteLineHeightLsb = spriteLineHeight & 0xFF;

  // special marker for Block header 0xFF, width and height of the block, spriteLineHeight, progressive rendering flag, updatable flag
  return Uint8List.fromList([
    0xFF,
    widthMsb,
    widthLsb,
    heightMsb,
    heightLsb,
    spriteLineHeightMsb,
    spriteLineHeightLsb,
    _progressiveRender ? 1 : 0,
    _updatable ? 1 : 0,
  ]);
}