Question

在我的UIScrollview中，我有一个黑色背景的UIImageView。在里面有另一个UIImageView里面有一个UIImage，我使用这段代码来启用缩放：

fullImageView = [[UIView alloc] initWithFrame:CGRectMake(0,0,screenWidth,screenHeight)];
fullImageView.backgroundColor = [UIColor blackColor];

[fullImageView addSubview:copyImageToShowImageView];

zoomFullImageScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0,0,screenWidth,screenHeight)];

[zoomFullImageScrollView addSubview:fullImageView];

[self.view addSubview:zoomFullImageScrollView];

UIPinchGestureRecognizer *twoFingerTapRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(doubleTapImage:)];

[copyImageToShowImageView addGestureRecognizer:twoFingerTapRecognizer];


//Then..

- (void)doubleTapImage:(UIPinchGestureRecognizer *)gesture{

if (gesture.state == UIGestureRecognizerStateEnded
    || gesture.state == UIGestureRecognizerStateChanged) {

    CGFloat currentScale = copyImageToShowImageView.frame.size.width / copyImageToShowImageView.bounds.size.width;
    CGFloat newScale = currentScale * gesture.scale;

    NSLog(@"gesture.scale = %f", currentScale * gesture.scale);

    if (newScale < 1) {
        newScale = 1;
    }
    if (newScale > 100) {
        newScale = 100;
    }

    CGAffineTransform transform = CGAffineTransformMakeScale(newScale, newScale);
    copyImageToShowImageView.transform = transform;
    gesture.scale = 1;

    copyImageToShowImageView.transform = CGAffineTransformTranslate(copyImageToShowImageView.transform, newScale, newScale);
    zoomFullImageScrollView.contentSize=CGSizeMake(copyImageToShowImageView.frame.size.width, copyImageToShowImageView.frame.size.height);
}
}

//and the methods:

- (void)viewDidLoad {

NSLog(@"super");

[super viewDidLoad];

zoomFullImageScrollView.minimumZoomScale=0.5;
zoomFullImageScrollView.maximumZoomScale=6.0;
zoomFullImageScrollView.delegate=self;
}

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{

    return copyImageToShowImageView;
}

此代码有效，但存在问题，因为scrollview内容大小与UIImageView大小不同。也许他们是平等但不一致的。然后我想在用户进行缩放时，图像放大，而不是总是从中心放大，但这并不重要。

我希望自己解释一下。

我该怎么办？

Answer 1

如果您将UIImageView放在UIScrollView中，它将使您的生活更轻松。

UIScrollView委托实现特定于Zoom的方法。因为它是可滚动的，所以你可以“移动”整个图像。

在UIScrollView的documentation中，您可以找到与缩放相关的优秀示例。

缩放UIImageView并在缩放内移动

1 个答案: