我将ImageView放入ViewController中,并且想用Pinch Gesture放大或缩小。另外,我想在用户双击图像时获得初始视图。我按照本教程Make Gallery

如果我仅使用捏合手势就能正常工作,则可以放大直到达到最大缩放,然后缩小直到达到最小缩放。右图为下图。

虽然,如果我双击ImageView,ImageView会获得其初始格式(图片1),但无法识别最小缩放的效果;如果我继续用捏手势进行缩小,则ImageView会继续缩小,并且我会得到此结果(图片2):

这些是我处理事件的方法:

@interface ImageGalleryViewController (){


NSString *productName;
CGFloat previousScale;
CGFloat previousRotation;
CGFloat beginX;
CGFloat beginY;

CGFloat scale;
//CGFloat __previousScale;
}

- (void)viewDidLoad{
[super viewDidLoad];
// Do any additional setup after loading the view.

   scale=1.0;

   UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc]       initWithTarget:self action:@selector(scaleImage:)];
   [self.view addGestureRecognizer:pinchGesture];

   UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(resetImage:)];
   tapGesture.numberOfTapsRequired=2;
   [self.view addGestureRecognizer:tapGesture];


}

 - (void)resetImage:(UITapGestureRecognizer *)recognizer{
     [UIView animateWithDuration:0.3 animations:^() {

     self.view.transform = CGAffineTransformIdentity;

     }];
     self.bigImage.transform = CGAffineTransformIdentity;
     [self.bigImage setCenter: CGPointMake(self.view.frame.size.width/2,self.view.frame.size.height/2+32)];
     [UIView commitAnimations];
 }

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

     NSLog(@"Scale: %f", [recognizer scale]);
     if ([recognizer state] == UIGestureRecognizerStateBegan) {
        previousScale = scale;
     }

     CGFloat currentScale = MAX(MIN([recognizer scale] * scale, 10), 1);
     CGFloat scaleStep = currentScale / previousScale;
     [self.view setTransform: CGAffineTransformScale(self.view.transform, scaleStep, scaleStep)];

    previousScale = currentScale;

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

那么,如果实现了初始右视图(第一张图像),如何停止缩小?

最佳答案

我不得不将变量重置为1.0到resetImage方法中。所以现在它可以正常工作了。

10-07 19:54
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