How could I implement x,y coordinates of a pixel color?

How can 开发者_StackOverflow中文版I implement X,Y coordinates of a piksel color with Objective C or C#? For example; at x:20,y:30 coordinates, rgb values are 255,255,255.

Thanks...

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Getting the color of a bitmap picture is part of the .net framework. You can then use the Color.A, R, G values. To perform a screencapture you can simply call the Graphics.CopyFromScreen method.

We'll need more info if that doesn't answer your question.

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I think space's example means: Given x and y screen coordinates of an iPhone display, what colour is the pixel that is currently showing there?

If that is the case, there is sample code here: http://www.markj.net/iphone-uiimage-pixel-color/