draw method

@override void draw({Canvas canvas, Image paintImage, double progress, Offset startingOffset})

Implementation

@override
void draw({
  Canvas canvas,
  ui.Image paintImage,
  double progress,
  Offset startingOffset,
}) {
  Paint paint = Paint();
  Size imageSize =
      Size(paintImage.width.toDouble(), paintImage.height.toDouble());
  if (_startingOffset != startingOffset) {
    calculateStartingCoordinate(
      size: imageSize,
      startingOffset: startingOffset,
    );
    _startingOffset = startingOffset;
  }
  double maxDistance = startingCoordinate.maxDistance(
    maxX: numberOfRow - 1,
    maxY: numberOfColumn - 1,
  );
  for (int i = 0; i < numberOfColumn; i++) {
    for (int j = 0; j < numberOfRow; j++) {
      double currentProgress = calculateFragmentProgress(
        maxDistance: maxDistance,
        currentCoordinate: Coordinate(x: j, y: i),
      );
      if (currentProgress > progress) {
        Rect rect = calculateFragment(i: i, j: j, size: imageSize);
        if (disableTransition == false) {
          double opacity = 1;
          double transition =
              (numberOfRow + numberOfColumn) / (numberOfRow * numberOfColumn);
          transition = min(transition, .1);
          if (currentProgress - transition < progress) {
            opacity = .6;
          } else if (currentProgress - transition / 2 < progress) {
            opacity = .8;
          }
          paint.color = Colors.white.withOpacity(opacity);
        }
        canvas.drawImageRect(paintImage, rect, rect, paint);
      }
    }
  }
}