问题描述
我在屏幕外的UIView(远大于320x480)上用3D转换了CALayer。
I have a CALayer transformed in 3D on a offscreen UIView (much larger than 320x480).
如何将UIView上看到的内容转储到UIImage?
How do I dump what is seen on this UIView to a UIImage?
注意:我已编辑问题以包含此代码...
这就是我创建图层的方式......
This is how I create the layer...
CGRect area = CGRectMake (0,0,400,600];
vista3D = [[UIView alloc] initWithFrame:area ];
[self.view addSubview:vista3D];
[vista3D release];
transformed = [CALayer layer];
transformed.frame = area;
[vista3D.layer addSublayer:transformed];
CALayer *imageLayer = [CALayer layer];
imageLayer.doubleSided = YES;
imageLayer.frame = area;
imageLayer.transform = CATransform3DMakeRotation(40 * M_PI / 180.0f, 1.0f, 0.0f, 0.0f);
imageLayer.contents = (id)myRawImage.CGImage;
[transformed addSublayer:imageLayer];
// Add a perspective effect
CATransform3D initialTransform = transformed.sublayerTransform;
initialTransform.m34 = 1.0 / -500;
transformed.sublayerTransform = initialTransform;
// now the layer is in perspective
// my next step is to "flatten" the composition into a UIImage
UIImage *thisIsTheResult = some magic command
感谢您的帮助!
编辑1:我已尝试过jessecurry解决方案,但它给了我一个没有任何视角的平面图层。
EDIT 1: I have tried jessecurry solution but it gives me a flat layer without any perspective.
编辑2:我发现了一个部分解决方案,但这个解决方案给了我一个大小与屏幕相同的图像,我正在寻找获得更高分辨率的版本,渲染屏幕。
EDIT 2: I discovered a partial solution for this that works, but this solution gives me an image the size of the screen and I was looking for obtaining a higher resolution version, rendering off screen.
推荐答案
在iPhone SDK的范围内,没有办法做到这一点。您可以使用 UIGetScreenImage
获取屏幕内容,或使用 - [CALayer renderInContext:]
将图层绘制到一个 CGContext
,但强制GPU只将一部分图层合成到一个缓冲区中,只能使用私有API和方法来实现。
Within the confines of the iPhone SDK, there is no way to do this. You can grab the contents of the screen with UIGetScreenImage
or use -[CALayer renderInContext:]
to have a layer draw into a CGContext
, but forcing the GPU to composite only a subset of layers into a buffer is something that can only be achieved using private APIs and methods.
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