convertRect:toView: 在iPad Retina和iPad 2上的表现不同。

Question

我有一段代码，在iPad2上运行得非常完美，但在Retina iPad上缩放出现了问题。

我在两台iPad上都执行了该应用程序，但行为完全不同。在Retina iPad上，图像回到原始位置，变换没有发生。

该代码获取一组视图，将它们添加到临时视图中，调整临时视图的大小，然后再将这些视图添加回来，以便同时调整它们的大小。

- (IBAction)scaleParts:(UIPinchGestureRecognizer *)sender {
if (sender.state == UIGestureRecognizerStateBegan) {
    self.tempCanvasView = [[UIView alloc] initWithFrame:self.canvas.bounds];
    self.tempCanvasView.backgroundColor = [UIColor redColor];
    for (UIView *view in [self.canvas subviews]) {
        CGRect currentFrame = view.bounds;
        CGRect newFrame = [view convertRect:currentFrame toView:self.tempCanvasView];
        view.bounds = newFrame;
        [self.tempCanvasView addSubview:view];
    }
    [self.canvas addSubview:self.tempCanvasView];
} else if (sender.state == UIGestureRecognizerStateChanged) {
    self.tempCanvasView.transform = CGAffineTransformScale(self.tempCanvasView.transform, sender.scale, sender.scale);
    sender.scale = 1.0;
} else if (sender.state == UIGestureRecognizerStateEnded) {
    for (UIView *view in [self.tempCanvasView subviews]) {
        CGRect currentFrame = view.bounds;
        CGRect newFrame = [view convertRect:currentFrame toView:self.canvas];
        view.frame = newFrame;
        [self.canvas addSubview:view];
    }
    [self.tempCanvasView removeFromSuperview];
    self.tempCanvasView = nil;
}
}

- zago

Answer 1

这里是一个正确的方法：

SWIFT：

extension UIView {

    func convertRectCorrectly(rect: CGRect, toView view: UIView) -> CGRect {
        if UIScreen.mainScreen().scale == 1 {
            return self.convertRect(rect, toView: view)
        }
        else if self == view {
            return rect
        }
        else {
            var rectInParent = self.convertRect(rect, toView: self.superview)
            rectInParent.origin.x /= UIScreen.mainScreen().scale
            rectInParent.origin.y /= UIScreen.mainScreen().scale
            let superViewRect = self.superview!.convertRectCorrectly(self.superview!.frame, toView: view)
            rectInParent.origin.x += superViewRect.origin.x
            rectInParent.origin.y += superViewRect.origin.y
            return rectInParent
        }
    }
}

- Alexander Volkov

Answer 2

也许你需要检测应用程序正在使用哪种屏幕类型（iPad的比例为1，iPadRetina的比例为2）。

CGFloat scale = [[UIScreen mainScreen] scale];

之后...

 if (scale==1) {
        //code from above
    } else {
        //code from above with small modification
    }

- TonyMkenu