我如何呈现，其中包含核心动画层位图一个看法？ [英] How do I render a view which contains Core Animation layers to a bitmap?
问题描述
我使用的是的NSView 来托管多个核心动画的CALayer 的对象。我希望能够做的就是抓住该视图的当前状态的快照作为位图图像。
I am using an NSView to host several Core Animation CALayer objects. What I want to be able to do is grab a snapshot of the view's current state as a bitmap image.
这是一个正常的的NSView 使用这样的事情比较简单：
This is relatively simple with a normal NSView using something like this:
void ClearBitmapImageRep(NSBitmapImageRep* bitmap) {
unsigned char* bitmapData = [bitmap bitmapData];
if (bitmapData != NULL)
bzero(bitmapData, [bitmap bytesPerRow] * [bitmap pixelsHigh]);
}
@implementation NSView (Additions)
- (NSBitmapImageRep*)bitmapImageRepInRect:(NSRect)rect
{
NSBitmapImageRep* imageRep = [self bitmapImageRepForCachingDisplayInRect:rect];
ClearBitmapImageRep(imageRep);
[self cacheDisplayInRect:rect toBitmapImageRep:imageRep];
return imageRep;
}
@end
然而，当我用这个code，核心动画层不会被渲染。
However, when I use this code, the Core Animation layers are not rendered.
我已经调查 CARenderer ，因为它似乎做什么，我需要，但我不能让它呈现现有的图层树。我试过如下：
I have investigated CARenderer, as it appears to do what I need, however I cannot get it to render my existing layer tree. I tried the following:
NSOpenGLPixelFormatAttribute att[] =
{
NSOpenGLPFAWindow,
NSOpenGLPFADoubleBuffer,
NSOpenGLPFAColorSize, 24,
NSOpenGLPFAAlphaSize, 8,
NSOpenGLPFADepthSize, 24,
NSOpenGLPFANoRecovery,
NSOpenGLPFAAccelerated,
0
};
NSOpenGLPixelFormat *pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:att];
NSOpenGLView* openGLView = [[NSOpenGLView alloc] initWithFrame:[self frame] pixelFormat:pixelFormat];
NSOpenGLContext* oglctx = [openGLView openGLContext];
CARenderer* renderer = [CARenderer rendererWithCGLContext:[oglctx CGLContextObj] options:nil];
renderer.layer = myContentLayer;
[renderer render];
NSBitmapImageRep* bitmap = [oglView bitmapImageRepInRect:[oglView bounds]];
不过，我这样做时，我得到一个异常：
However, when I do this I get an exception:
CAContextInvalidLayer - 层LT; CALayer的：0x1092ea0＆GT;已经连接到上下文
我猜这一定是因为该层树在我的的NSView 托管，因此附着于它的上下文。我不明白我怎么可以从的NSView ，以便将其渲染为位图分离层树，它的不平凡在这种情况下创建重复层树。
I'm guessing that this must be because the layer tree is hosted in my NSView and therefore attached to its context. I don't understand how I can detach the layer tree from the NSView in order to render it to a bitmap, and it's non-trivial in this case to create a duplicate layer tree.
有一些其他的方式来获得的CALayer s到渲染为位图？我找不到任何样品code这样做的任何地方，其实我找不到任何样品$ C $为 CARenderer 在所有的C
Is there some other way to get the CALayers to render to a bitmap? I can't find any sample code anywhere for doing this, in fact I can't find any sample code for CARenderer at all.
推荐答案
有一个伟大的职位上可可是我的女朋友关于录制动画的核心。作者抓住了整个动画拍成电影，但你可以使用他抓起一帧的部分。结果
跳转到本文中的获取当前帧部分：结果
<一href=\"http://www.cimgf.com/2009/02/03/record-your-core-animation-animation/\">http://www.cimgf.com/2009/02/03/record-your-core-animation-animation/
There is a great post on "Cocoa is my girlfriend" about recording Core Animations. The author captures the whole animation into a movie, but you could use the part where he grabs a single frame.
Jump to the "Obtaining the Current Frame" section in this article:
http://www.cimgf.com/2009/02/03/record-your-core-animation-animation/
的基本思想是：
- 创建一个CGContext上
- 使用<一个href=\"http://developer.apple.com/mac/library/DOCUMENTATION/GraphicsImaging/Reference/CALayer%5Fclass/Introduction/Introduction.html#//apple%5Fref/occ/instm/CALayer/renderInContext%3A\">CALayer's
renderInContext： - 从创建NSBitmapImageRep
（当使用
CGBitmapContextCreateImage和
NSBitmapImageRep的initWithCGImage）
更新：结果
我刚才读，即 renderInContext：方法不支持所有类型层在Mac OS X 10.5。
它不为以下层类工作：
Update:
I just read, that the renderInContext: method does not support all kind of layers in Mac OS X 10.5.
It does not work for the following layers classes:
- QCCompositionLayer
- CAOpenGLLayer
- QTMovieLayer
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