iphone - 我在 ImageView 中使用了 PinchGesture。此代码运行完美，现在我想在某个尺寸处停止 ZoomOut，我该怎么办？

Question

我在我的ImageView中使用了PinchGesture。此代码运行完美，现在我想在某个尺寸处停止ZoomOut，我应该做什么？

UIPanGestureRecognizer *panGesture=[[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(handlePan:)];
    panGesture.delegate=self;
    [overlayimageView addGestureRecognizer:panGesture];


- (void)handlePinch:(UIPinchGestureRecognizer *)recognizer
{

    recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, recognizer.scale, recognizer.scale);
    recognizer.scale = 1;
}

Answer 1

CGFloat scale = 1.0 - (ImageLastScale - pinchscale);
CGRect bounds = [(UIPinchGestureRecognizer*)sender view].bounds;
scale = MIN(scale, maximumHeight / CGRectGetHeight(bounds));//define maximumHeight and minimumHeight for zoom level
scale = MAX(scale, minimumHeight / CGRectGetHeight(bounds));

使用方法，我像下面这样使用它。将lastScale变量定义为.h文件中的Float对象

-(void)scale:(id)sender {

    if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {
        lastScale = 1.0;
        return;
    }

    CGFloat pinchscale = [(UIPinchGestureRecognizer*)sender scale];
    CGFloat scale = 1.0 - (lastScale - pinchscale);
    CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform;
    CGAffineTransform holderTransform = holderView.transform;
    CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);
    [[(UIPinchGestureRecognizer*)sender view] setTransform:newTransform];

    CGFloat scale = 1.0 - (lastScale - pinchscale);
    CGRect bounds = [(UIPinchGestureRecognizer*)sender view].bounds;
    scale = MIN(scale, maximumHeight / CGRectGetHeight(bounds));
    scale = MAX(scale, minimumHeight / CGRectGetHeight(bounds));

    lastScale = [(UIPinchGestureRecognizer*)sender scale];
}

已更新

    UIPinchGestureRecognizer *pinchGesture=[[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(scale:)];
    pinchGesture.delegate=self;
    [overlayimageView addGestureRecognizer:pinchGesture];

希望这个回答对你有帮助..