比较UIImage [英] Comparing UIImage

问题描述

如何将图片与另一张图片进行比较？

How can I compare an image to another one?

谢谢！

推荐答案

如果你有两个UIImages，你应该得到他们的 CGImageRef quartz来自这些对象的表示。然后创建两个新的位图上下文，由您创建和传递的内存缓冲区支持，每个图像一个。然后使用 CGContextDrawImage 将图像绘制到位图上下文中。现在图像的字节在缓冲区中。您可以手动循环或 memcmp 来检查差异。

If you have two UIImages, you should get their CGImageRef quartz representations from those objects. Then create two new bitmap contexts backed by a memory buffer that you create and pass in, one for each of the images. Then use CGContextDrawImage to draw the images into the bitmap contexts. Now the bytes of the images are in the buffers. You can then loop through manually or memcmp to check for differences.

Apple自己的详细解释和示例代码位图上下文和绘图到这里：

Apple's own detailed explanation and sample code around creating bitmap contexts and drawing into them is here:

http://developer.apple.com/iphone/library/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/ dq_context / dq_context.html＃// apple_ref / doc / uid / TP30001066-CH203-CJBHBFFE

您的区别在于您正在绘制现有图像到上下文中。使用 CGContextDrawImage 。

The difference for you is that you're drawing an existing image into the context. Use CGContextDrawImage for this.

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