核心动画绕任意点旋转一层 [英] Core Animation rotating a layer around arbitrary point

问题描述

如何使用Core Animation围绕任意点旋转图层？ （在我的情况下，一个点不在层内我想旋转）

我喜欢这样做而不改变锚点，因为除非我每次都得到错误我改变了锚点，它也改变了层的位置。

我尝试这样的，但它不工作：

  [UIImageView beginAnimations：nil context：nil]; 
 CATransform3D rotationTransform = CATransform3DIdentity; 
 rotationTransform = CATransform3DTranslate（rotationTransform，0.0，-100.0，0.0）; 
 rotationTransform = CATransform3DRotate（rotationTransform，DegreesToRadians（180），
 0.0，0.0，1.0）; 
 rotationTransform = CATransform3DTranslate（rotationTransform，0.0，100.0，0.0）
 shape1.layer.transform = rotationTransform; 
 [UIImageView commitAnimations]; 
  

看起来旋转轴在旋转过程中移动。

<我最终通过创建一个新的更大的图层，它的中心在我的旋转轴和设置图层我想旋转作为它的子图层。

然后我旋转较大的图层而不是子图层

How can I rotate a layer using Core Animation around an arbitrary point? ( In my case a point that is not inside the layer I want to rotate )

I prefer doing this without changing the anchor point, because unless I get something wrong every time I change the anchor point it also changes the position of the layer.

I tried something like that but it didn't work:

[UIImageView beginAnimations:nil context:nil];
CATransform3D rotationTransform = CATransform3DIdentity;
rotationTransform = CATransform3DTranslate(rotationTransform, 0.0, -100.0, 0.0);
rotationTransform = CATransform3DRotate(rotationTransform, DegreesToRadians(180),
                        0.0, 0.0, 1.0);
rotationTransform = CATransform3DTranslate(rotationTransform, 0.0, 100.0, 0.0)
shape1.layer.transform = rotationTransform;
[UIImageView commitAnimations];

It looks like the rotation axis is moving during the rotate.

解决方案

I finaly did it by creating a new bigger layer with it's center at my rotation axis and setting the layer i want to rotate as it's sub layer.

Then I rotate the bigger layer instead of the sub layer

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