getClip method

@override Rect getClip(Size size)

Returns a description of the clip given that the render object being clipped is of the given size.

Implementation

@override
Rect getClip(Size size) {
  // center of rectangle
  final center = new Offset(size.width / 2, size.height * 0.9);

  // Calculate distance from center to the top left corner to make sure we fill the screen via simple trigonometry.
  double theta = atan(center.dy / center.dx);
  final distanceToCorner = center.dy / sin(theta);

  final radius = distanceToCorner * revealPercent!;
  final diameter = 2 * radius;

  return new Rect.fromLTWH(
      center.dx - radius, center.dy - radius, diameter, diameter);
}