Does Quartz2D test intersection of rect by line before drawing it.

Posted by ddnv on Stack Overflow See other posts from Stack Overflow or by ddnv
Published on 2010-04-02T15:46:28Z Indexed on 2010/04/02 17:13 UTC
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Filed under:

objective-c

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iphone-sdk

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geometry

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quartz-2d

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core-graphics

I'm drawing a big scheme that consist of a lot of lines. I do it in the drawRect: method of UIView. The scheme is larger than the layer of view and I check each line and draw it only if it intersects the visible rect. But at one moment I thought, should I do this? Maybe Quartz is already doing this test?

So the question is: When I use function CGContextAddLineToPoint() does the Core Graphics tests this line for intersection with layer rect or it just draw it anyway?

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