CGAffineTransform：UIButton 上的旋转调整按钮图像的大小
我在使用 UIButtons 时遇到了一个奇怪的问题，输入 custom。我将其中 4 个按钮放置在 UIScrollview 上，并使用 CGAffineTransform 将每个按钮旋转随机角度。现在看来按钮本身会根据旋转角度改变大小。
UIGraphicsBeginImageContext(tempCtxSize);
[cookbookImage drawInRect:CGRectMake(imgOffsetX, imgOffsetY+frmOffsetY, cookbookImage.size.width, cookbookImage.size.height)];
[cookbookFrame drawInRect:CGRectMake(0.0f, frmOffsetY, cookbookFrame.size.width, cookbookFrame.size.height)];
UIImage *combinedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
…
UIButton *cookbookViewButton = [UIButton buttonWithType:UIButtonTypeCustom];
[cookbookViewButton setFrame:CGRectMake(0.0f, 0.0f, combinedImage.size.width, combinedImage.size.height)];
[cookbookViewButton setBackgroundColor:[UIColor clearColor]];
[cookbookViewButton setBackgroundImage:combinedImage forState:UIControlStateNormal];
CGAffineTransform rotation = [cookbookViewButton transform];
rotation = CGAffineTransformRotate(rotation, angle); // some random angle
[cookbookViewButton setTransform:rotation];
I've got a strange problem using UIButtons, type custom. I'm placing 4 of those buttons on a UIScrollview, rotating each button by a random angle using CGAffineTransform. Now it seems that the buttons themselves change size depending on the angle of rotation.
UIGraphicsBeginImageContext(tempCtxSize);
[cookbookImage drawInRect:CGRectMake(imgOffsetX, imgOffsetY+frmOffsetY, cookbookImage.size.width, cookbookImage.size.height)];
[cookbookFrame drawInRect:CGRectMake(0.0f, frmOffsetY, cookbookFrame.size.width, cookbookFrame.size.height)];
UIImage *combinedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
…
UIButton *cookbookViewButton = [UIButton buttonWithType:UIButtonTypeCustom];
[cookbookViewButton setFrame:CGRectMake(0.0f, 0.0f, combinedImage.size.width, combinedImage.size.height)];
[cookbookViewButton setBackgroundColor:[UIColor clearColor]];
[cookbookViewButton setBackgroundImage:combinedImage forState:UIControlStateNormal];
CGAffineTransform rotation = [cookbookViewButton transform];
rotation = CGAffineTransformRotate(rotation, angle); // some random angle
[cookbookViewButton setTransform:rotation];
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这是一个系统错误：
“
重要如果视图的变换属性不包含恒等变换，则该视图的框架是未定义的，其自动调整大小行为的结果也是如此。”来自：使用自动调整大小规则自动处理布局更改< /a>
解决方案：将父视图的autoResizeSubviews设置为NO。
This is a system bug:
"
ImportantIf a view’s transform property does not contain the identity transform, the frame of that view is undefined and so are the results of its autoresizing behaviors."from: Handling Layout Changes Automatically Using Autoresizing Rules
Solution: set the parent view's autoResizeSubviews to NO.
不要设置 CookbookViewButton 的框架 - 设置边界。
Don't set the frame of cookbookViewButton - set the bounds.