Is it possible to erase drawing made by NSRectFill?

I have been using NSRectFill to draw rectangles on the screen. I would like to erase t开发者_StackOverflowhese rectangles. I can't paint over them, as the back ground behind them is textured and can't be replicated with a solid color. Is this possible?

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I don't know much Objective-C, or Cocoa, so I can't give you details, but here's how my Windows oriented mind thinks:

Simply request a redrawing of the window, and then don't paint the rectangles.

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Just draw the background again.