捏合手势 随意放大缩小

- (void)pinchAction:(UIPinchGestureRecognizer *)sender {

    

    

    if (sender.state == UIGestureRecognizerStateEnded) {

        

        CGRect rect = self.imagev.frame;

        self.imagev.transform = CGAffineTransformIdentity;//重置坐标

        self.imagev.frame = rect;

    } else if (sender.state == UIGestureRecognizerStateBegan) {

        

        CGPoint pinchCenter = [sender locationInView:sender.view];

        CGPoint previousAnchorPoint = self.imagev.layer.anchorPoint;

        CGPoint newAnchorPoint = CGPointMake(pinchCenter.x / self.imagev.frame.size.width, pinchCenter.y / self.imagev.frame.size.height);

        CGPoint previousPosition = self.imagev.layer.position;

        CGPoint newPosition = CGPointZero;

        newPosition.x = previousPosition.x + (newAnchorPoint.x - previousAnchorPoint.x) * self.imagev.frame.size.width;

        newPosition.y = previousPosition.y + (newAnchorPoint.y - previousAnchorPoint.y) * self.imagev.frame.size.height;

        

        self.imagev.layer.position = newPosition;

        self.imagev.layer.anchorPoint = newAnchorPoint;

        

    } else {

        

        

        self.imagev.transform = CGAffineTransformMakeScale(sender.scale, sender.scale);

    }

}