如何用uipinchsturerecognizer检测或定义缩放手势的方向?

I'm using UIPinchGestureRecognizer to detect pinch gestures, something like:

我用uipinchsturerecognizer来检测捏手势，比如:

- (void) initPinchRecon {
 UIPinchGestureRecognizer *pinchRecognizer = [[[UIPinchGestureRecognizer alloc] 
              initWithTarget:self
              action:@selector(Perform_Pinch:)] autorelease];
 [self addGestureRecognizer:pinchRecognizer];

 [pinchRecognizer setScale:20.0f];
}

- (void) Perform_Pinch:(UIPinchGestureRecognizer*)sender{
 NSLog(@"PINCH");
} 

And it works well to detect a simple pinch gesture: It's possible to determine (or define myself) the angle or orientation of the pinch gesture ?, for example, to differentiate between an horizontal and an vertical pinch gesture ?

它能很好地检测一个简单的缩放手势:可以确定(或定义我自己)缩放手势的角度或方向，例如，区分水平和垂直的缩放手势?

Thanks

谢谢

1 个解决方案

#1

A very simple solution is to implement the gesture handler like this:

一个非常简单的解决方案是实现这样的手势处理程序:

-(void)handlePinchGesture:(UIPinchGestureRecognizer *)recognizer {
if (recognizer.state != UIGestureRecognizerStateCancelled) {
    if (recognizer.numberOfTouches == 2) {
        CGPoint firstPoint = [recognizer locationOfTouch:0 inView:recognizer.view];
        CGPoint secondPoint = [recognizer locationOfTouch:1 inView:recognizer.view];

        CGFloat angle = atan2(secondPoint.y - firstPoint.y, secondPoint.x - firstPoint.x);

        // handle the gesture based on the angle (in radians)
    }
}