iphone - 如何使用UIPinchGestureRecognizer设置最小和最大缩放比例

我想放大和缩小 ImageView ，但我不想为此使用UIScrollView。
所以为此，我使用了UIPinchGestureRecognizer，这是我的代码-

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

这对于放大和缩小工作正常。
但是问题是我想放大和缩小特定的比例，例如在UIScrollView中，我们可以设置maxZoom和minZoom。我找不到任何解决方案，每个有关UIPinchGestureRecognizer的教程都只描述相同的代码。

最佳答案

在处理手势的类的界面中声明2个ivat CGFloat __scale和CGFloat __previousScale。通过覆盖__scale函数之一将1.0设置为init(确保在此处调用 super 构造函数)。

- (void)zoom:(UIPinchGestureRecognizer *)gesture {
    NSLog(@"Scale: %f", [gesture scale]);

    if ([gesture state] == UIGestureRecognizerStateBegan) {
        __previousScale = __scale;
    }

    CGFloat currentScale = MAX(MIN([gesture scale] * __scale, MAX_SCALE), MIN_SCALE);
    CGFloat scaleStep = currentScale / __previousScale;
    [self.view setTransform: CGAffineTransformScale(self.view.transform, scaleStep, scaleStep)];

    __previousScale = currentScale;

    if ([gesture state] == UIGestureRecognizerStateEnded ||
        [gesture state] == UIGestureRecognizerStateCancelled ||
        [gesture state] == UIGestureRecognizerStateFailed) {
        // Gesture can fail (or cancelled?) when the notification and the object is dragged simultaneously
        __scale = currentScale;
        NSLog(@"Final scale: %f", __scale);
    }
}

关于iphone - 如何使用UIPinchGestureRecognizer设置最小和最大缩放比例，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/10958624/