以下是我的手势识别器的当前实现:
- (IBAction)handleRotate:(UIRotationGestureRecognizer *)recognizer {
if([recognizer state] == UIGestureRecognizerStateEnded) {
_lastRotation = 0.0;
return;
}
CGFloat rotation = 0.0 - (_lastRotation - [recognizer rotation]);
CGAffineTransform currentTransform = self.container.transform;
CGAffineTransform newTransform = CGAffineTransformRotate(currentTransform,rotation);
[self.container setTransform:newTransform];
_lastRotation = [recognizer rotation];
}
运行良好。问题在于self.container始终围绕其中心旋转。我希望它围绕两个触摸点的中点旋转,这样如果你放大了,就可以围绕你触摸的区域旋转。我该怎么做?