transformRect method

Rect transformRect (Matrix4 transform, Rect rect)

Returns a rect that bounds the result of applying the given matrix as a perspective transform to the given rect.

This function assumes the given rect is in the plane with z equals 0.0. The transformed rect is then projected back into the plane with z equals 0.0 before computing its bounding rect.

Implementation 

static Rect transformRect(Matrix4 transform, Rect rect) {
  final Offset point1 = transformPoint(transform, rect.topLeft);
  final Offset point2 = transformPoint(transform, rect.topRight);
  final Offset point3 = transformPoint(transform, rect.bottomLeft);
  final Offset point4 = transformPoint(transform, rect.bottomRight);
  return Rect.fromLTRB(
      _min4(point1.dx, point2.dx, point3.dx, point4.dx),
      _min4(point1.dy, point2.dy, point3.dy, point4.dy),
      _max4(point1.dx, point2.dx, point3.dx, point4.dx),
      _max4(point1.dy, point2.dy, point3.dy, point4.dy)
  );
}