发布CGImage（CGImageRef） [英] Releasing CGImage (CGImageRef)

问题描述

我很好奇我是否正在使用CGImageRef跟踪正确的内存管理，我正在通过几种方法（因为它是CG对象，我认为它不支持自动释放）。使用非NSObjects进行内存管理以及与其他NSObject的交互对我来说仍然有点新鲜。

I'm curious if I'm following proper memory management with CGImageRef, which I'm passing through several methods (since it's CG object, I assume it doesn't support autorelease). Memory management with non-NSObjects and interaction with other NSObjects is still somewhat new to me.

这里我正在做的事情：

我正在使用CGBitmapContextCreateImage（保留计数1）在我的图像缓存管理器中创建CGImageRef，并将其添加到NSMutableDictionary（保留计数2）。

I'm creating the CGImageRef inside my image cache manager with CGBitmapContextCreateImage (retain count 1), and adding it to the NSMutableDictionary (retain count 2).

当CALayers使用图像时，我分配了layer.contents（保留计数+1），并在删除图层之前使用layer.contents = nil（保留计数-1）清除内容。

When CALayers use the image, I assign with layer.contents (retain count +1), and clearing contents with layer.contents = nil (retain count -1) before removing the layer.

最后，在清除纹理时，我调用CGImageRefRelease和[NSMutableDictionary removeObject]使保留计数为0.。

Finally, when clearing the texture, I call CGImageRefRelease and [NSMutableDictionary removeObject] to have retain count as 0.

这是一种正确的方法吗？

Is this a proper way to do so?

推荐答案

Core Foundation对象（所有Core Graphics对象都支持）支持自动发布。

您描述的步骤应该正常工作，不会泄漏或过度释放对象。

The steps you describe should work just fine and not leak or over-release the object.

我使用 CFRelease 而不是像 CGImageRelease 这样的特定类发布函数，但纯粹是作为一种风格问题。我只需要注意 NULL ： CGImageRelease 检查 NULL ，而 CFRelease 在传递 NULL 时会崩溃。使用 CGImageRelease 及其兄弟姐妹意味着你不必担心这个。

I use CFRelease instead of specific-class release functions like CGImageRelease, but purely as a matter of style. I just have to beware of NULL: CGImageRelease checks for NULL, whereas CFRelease will crash when passed NULL. Using CGImageRelease and its siblings means you don't have to worry about this.

我假设你的意思 removeObject：forKey：，而不是 removeObject （它不存在，无论如何也无法指定对象）。

I'm assuming you meant removeObject:forKey:, not removeObject (which doesn't exist and wouldn't have somewhere to specify an object anyway).

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