Question

有没有办法在不复制基础像素数据的情况下从屏幕外表面创建UIImage对象？

我想做这样的事情：

// These numbers are made up obviously...
CGContextRef offscreenContext = MyCreateBitmapContext(width, height);

// Draw into the offscreen buffer
// Draw commands not relevant...

// Convert offscreen into CGImage
// This consumes ~15MB
CGImageRef offscreenContextImage = CGBitmapContextCreateImage(offscreenContext);

// This allocates another ~15MB
// Is there any way to share the bits from the 
// CGImageRef instead of copying the data???
UIImage * newImage = [[UIImage alloc] initWithCGImage:offscreenContextImage];

// Releases the original 15MB, but the spike of 30MB total kills the app.
CGImageRelease(offscreenContextImage);
CGContextRelease(offscreenContext);

内存被释放并以可接受的大小进行调整，但30MB的内存峰值会杀死应用程序。有没有办法分享像素数据？

我考虑将屏幕外缓冲区保存到文件并再次加载数据，但这是一个黑客攻击，iPhone的便捷方法需要UIImage才能保存...

Answer 1

您可以尝试在创建CGImage之后立即释放上下文，释放上下文使用的内存，因为CGBitmapContextCreateImage（）会创建上下文的副本。

像这样：

CGImageRef offscreenContextImage = CGBitmapContextCreateImage(offscreenContext);

CGContextRelease(offscreenContext);

UIImage * newImage = [[UIImage alloc] initWithCGImage:offscreenContextImage];

// ...

CGImageRelease(offscreenContextImage);

Answer 2

也许

UIImage *newImage = [[UIImage alloc[ initWithData:offScreenContext];

在CGImageRef和UIImage之间共享内存

2 个答案: