diff method

Offset? diff()

返回终点与始点的差距

Implementation

Offset? diff() {
  if (scaleUpdateDetails != null && scaleStartDetails != null) {
    final dx = scaleUpdateDetails!.localFocalPoint.dx -
        scaleStartDetails!.localFocalPoint.dx;
    final dy = scaleUpdateDetails!.localFocalPoint.dy -
        scaleStartDetails!.localFocalPoint.dy;
    return Offset(dx, dy);
  }
  return null;
}