Uiview Zoom In/Out的特定部分，而不会增加视图目标C IOS的高度/宽度

Question

i实现了此。但问题是它通过缩放增加视图的高度/宽度。如何放大而不增加hight/width。我的Uiview Hight/Width是固定的。我的基本目的是，视图/宽度保持不变，但视图的内侧缩小。

    UIPinchGestureRecognizer * pinGeture =  [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(twoFingerPinch:)];
    [radarViewHolder addGestureRecognizer:pinGeture];

- (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer
{
    NSLog(@"Pinch scale: %f", recognizer.scale);
    if([recognizer state] == UIGestureRecognizerStateBegan) {
        // Reset the last scale, necessary if there are multiple objects with different scales
        lastScale = [recognizer scale];
    }
    if ([recognizer state] == UIGestureRecognizerStateBegan ||
        [recognizer state] == UIGestureRecognizerStateChanged) {
        CGFloat currentScale = [[[recognizer view].layer valueForKeyPath:@"transform.scale"] floatValue];
        // Constants to adjust the max/min values of zoom
        const CGFloat kMaxScale = 2.0;
        const CGFloat kMinScale = 1.0;
        CGFloat newScale = 1 -  (lastScale - [recognizer scale]);
        newScale = MIN(newScale, kMaxScale / currentScale);
        newScale = MAX(newScale, kMinScale / currentScale);
        CGAffineTransform transform = CGAffineTransformScale([[recognizer view] transform], newScale, newScale);
        [recognizer view].transform = transform;
        lastScale = [recognizer scale];  // Store the previous scale factor for the next pinch gesture call
    }
}

Answer 1

在子视图中添加您的视图。

[yourScroll addSubView:radarViewHolder];

- (void)scrollViewDidZoom:(UIScrollView *)scrollView
{
    CGFloat size = scrollView.zoomScale;
    if (size > ZoomMaxValue)
    {
        yourScroll.zoomScale = maximumScale;
    }
    if (size > ZoomMinValue && size < ZoomValue && size < 1.01)
    {
        yourScroll.zoomScale = minimumScale;
    }
    ZoomValue = size;
}

Answer 2

@shahbazakram声明一个float变量 CGFloat lastScale;

将此方法替换为您的代码。

- (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer
{
    NSLog(@"Pinch scale: %f", recognizer.scale);
    if([recognizer state] == UIGestureRecognizerStateBegan) {
        // Reset the last scale, necessary if there are multiple objects with different scales
        lastScale = [recognizer scale];
    }
    if ([recognizer state] == UIGestureRecognizerStateBegan ||
        [recognizer state] == UIGestureRecognizerStateChanged) {
        CGFloat currentScale = [[[recognizer view].layer valueForKeyPath:@"transform.scale"] floatValue];
        // Constants to adjust the max/min values of zoom
        const CGFloat kMaxScale = 2.0;
        const CGFloat kMinScale = 1.0;
        CGFloat newScale = 1 -  (lastScale - [recognizer scale]);
        newScale = MIN(newScale, kMaxScale / currentScale);
        newScale = MAX(newScale, kMinScale / currentScale);
        CGAffineTransform transform = CGAffineTransformScale([[recognizer view] transform], newScale, newScale);
        [recognizer view].transform = transform;
        lastScale = [recognizer scale];  // Store the previous scale factor for the next pinch gesture call
    }
}

Answer 3

在视图上使用变换时，其帧的Getter将与此转换相乘。因此，内部框架没有真正更新。

这通常不是问题，但在某些情况下可能是。通常，避免这种情况，您需要做的就是将视图添加到另一个视图中，然后扩展监督。假设这样的代码：

let baseView = UIView(frame: CGRect(x: 0.0, y: 0.0, width: 50.0, height: 50.0))
baseView.backgroundColor = .red
let addedView = UIView(frame: CGRect(x: 0.0, y: 0.0, width: 50.0, height: 50.0))
addedView.backgroundColor = .green
baseView.addSubview(addedView)
baseView.transform = CGAffineTransform(scaleX: 3.0, y: 3.0)

（对不起，Swift，但对您的情况没有区别）

当打印这两个视图时，结果为

baseView: (-50 -50; 150 150)
addedView: (0 0; 50 50)

，但从视觉上看，这两个视图是相同的，并且添加的视图完全重叠了基本视图。

在您的情况下，没有足够的代码来显示特定的修复程序，但是如果您为当前拥有的视图创建基本视图并扩展基本视图，则应使用更改框架的问题进行修复。