project method

@override Shape project(Transform2D transform, [ Shape? target ])

Returns the result of applying an affine transformation to the shape.

Certain shapes may be transformed into shapes of a different kind during the projection. For example, a Circle may transform into an Ellipse, and Rectangle into a Polygon.

If target is provided and it has a proper type, then this method should modify the target in-place and return it. If target is null, or if its type is not compatible with the requested transform, then the method should create and return a new Shape.

Implementation

@override
Shape project(Transform2D transform, [Shape? target]) {
  if (transform.isAxisAligned && transform.isConformal) {
    final v1 = transform.localToGlobal(Vector2(_left, _top));
    final v2 = transform.localToGlobal(Vector2(_right, _bottom));
    final newLeft = min(v1.x, v2.x);
    final newRight = max(v1.x, v2.x);
    final newTop = min(v1.y, v2.y);
    final newBottom = max(v1.y, v2.y);
    final newRadius = transform.scale.x.abs() * _radius;
    if (target is RoundedRectangle) {
      target._left = newLeft;
      target._right = newRight;
      target._top = newTop;
      target._bottom = newBottom;
      target._radius = newRadius;
      target._aabb = null;
      return target;
    } else {
      return RoundedRectangle.fromLTRBR(
        newLeft,
        newTop,
        newRight,
        newBottom,
        newRadius,
      );
    }
  }
  throw UnimplementedError();
}