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标题: iphone - UIPinchGestureRecognizer 用于在 xcode 中缩放和平移图像 [打印本页]

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作者: 菜鸟教程小白    时间: 2022-12-13 12:39
标题: iphone - UIPinchGestureRecognizer 用于在 xcode 中缩放和平移图像

我创建了一个应用程序，其中有一个包含 ImageView 的 View 。 下面使用 UIPinchGestureRecognizer 缩放图像的代码正在工作。 这里 innerview 是我的 View 的名称。

 - (void)viewDidLoad
    {
[super viewDidLoad];

//Zoom Photo
UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self actionselector(handlePinch];
[innerview addGestureRecognizer:pinchGesture];
[pinchGesture release];
mCurrentScale = 0;
mLastScale = 0;
}

-(void)handlePinchUIPinchGestureRecognizer*)sender {

NSLog(@"latscale = %f",mLastScale);

mCurrentScale += [sender scale] - mLastScale;
mLastScale = [sender scale];

if (sender.state == UIGestureRecognizerStateEnded)
{
    mLastScale = 1.0;
}

CGAffineTransform currentTransform = CGAffineTransformIdentity;
CGAffineTransform newTransform = CGAffineTransformScale(currentTransform,mCurrentScale, mCurrentScale);
innerview.transform = newTransform;

 } 

但是如何使用 ScrollView 来正确查看图像呢？

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Best Answer-推荐答案

在 ScrollView 中嵌入你的 innerView 完成捏合后，您可以获取新图像的大小，然后设置其内容大小

-(void)scaleid)sender {
  if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {
    lastScale = 1.0;
    CGSize zoomViewSize = CGSizeApplyAffineTransform(imgScrollView.frame.size, [(UIPinchGestureRecognizer *)sender view].transform);
    CGPoint centerPoint = CGPointApplyAffineTransform(imgScrollView.frame.origin, [(UIPinchGestureRecognizer *)sender view].transform);

    CGRect r = imgScrollView.bounds;
    CGSize scrollViewSize = imgScrollView.frame.size;
    imgScrollView.contentSize = zoomViewSize;
    imgScrollView.contentOffset = centerPoint; 
  }

  CGFloat currentScale = [[[(UIPinchGestureRecognizer*)sender view].layer valueForKeyPath"transform.scale"] floatValue];

  CGFloat scale = 1.0 - (lastScale - [(UIPinchGestureRecognizer*)sender scale]);
  scale = MIN(scale, imgScrollView.maximumZoomScale / currentScale);   
  scale = MAX(scale, imgScrollView.minimumZoomScale / currentScale);
  CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform;
  CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);
  [[(UIPinchGestureRecognizer*)sender view] setTransform:newTransform];
  lastScale = [(UIPinchGestureRecognizer*)sender scale];    
}

希望对你有帮助

关于iphone - UIPinchGestureRecognizer 用于在 xcode 中缩放和平移图像，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/9954582/

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