从CIImage获取CGImage [英] Getting a CGImage from CIImage

问题描述

我有一个从CIImage加载的UIImage：

I have a UIImage which is loaded from a CIImage with:

tempImage = [UIImage imageWithCIImage：ciImage];

问题是我需要将 tempImage 裁剪为特定的 CGRect ，我知道如何做到这一点的唯一方法是使用 CGImage 。
问题是在iOS 6.0文档中我发现了这个：

The problem is I need to crop tempImage to a specific CGRect and the only way I know how to do this is by using CGImage. The problem is that in the iOS 6.0 documentation I found this:

CGImage

如果使用CIImage对象初始化UIImage对象，则该属性的值为NULL。

A。如何转换CIImage至CGImage？
我正在使用此代码，但我有内存泄漏（并且无法理解在哪里）：

A. How to convert from CIImage to CGImage? I'm using this code but I have a memory leak (and can't understand where):

+(UIImage*)UIImageFromCIImage:(CIImage*)ciImage {  
    CGSize size = ciImage.extent.size;  
    UIGraphicsBeginImageContext(size);  
    CGRect rect;  
    rect.origin = CGPointZero;  
    rect.size   = size;  
    UIImage *remImage = [UIImage imageWithCIImage:ciImage];  
    [remImage drawInRect:rect];  
    UIImage *result = UIGraphicsGetImageFromCurrentImageContext();  
    UIGraphicsEndImageContext();  
    remImage = nil;  
    ciImage = nil;  
    //
    return result;  
}

推荐答案

查看 CIContext createCGImage：fromRect：

CGImageRef img = [myContext createCGImage:ciImage fromRect:[ciImage extent]];

从回答类似问题： https://stackoverflow.com/a/10472842/474896

此外，因为你有 CIImage 首先，您可以使用 CIFilter 来实际裁剪图像。

Also since you have a CIImage to begin with, you could use CIFilter to actually crop your image.

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