Is it possible to detect intersection of CGMutablePathRef and CGRect ?

Question

I have a sprite with its bounding box and I want to detect the intersection of it with a CGMutablePathRef. How would I do that ?

score 1 · Answer 1 · edited May 23 '17 at 12:10

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There's no readily available solution for that. It also depends on what features of CGPath you are using. If it's just a series of points, you can use a regular line with rectangle intersection test.

Everything else (eg bezier curve and rectangle intersection) is going to be very complicated.

edited May 23 '17 at 12:10

Community

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answered Dec 29 '11 at 20:55

CodeSmile

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Thank you for your response. I indeed do not have a curve but a hexagon shape. Do I have to create these lines separate from the hexagon or are they handled as separate lines anyway ? – the_critic Dec 31 '11 at 16:08

score 1 · Answer 2 · answered Dec 29 '11 at 21:46

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If it's a pure rectangular comparison, you can use CGPathGetBoundingBox to obtain the path's bounding box and then use CGRectIntersectsRect to determine if the intersection occurs.

answered Dec 29 '11 at 21:46

jstevenco

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This is useful too, thank you, but for me it is just a temporary solution as I do not want to detect the path's bounding box, but rather its proper shape. – the_critic Dec 31 '11 at 16:25

score 1 · Answer 3 · answered Dec 30 '11 at 00:41

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Depending on performance needs, draw into a 1-bit deep bitmap, clipping to the CGRect. Then scan for a pixel. (This technique tends to be more appropriate for testing to a point.)

answered Dec 30 '11 at 00:41

David Dunham

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This approach also appeals to me, thank you very much, I'll try it out. – the_critic Dec 31 '11 at 16:23

Is it possible to detect intersection of CGMutablePathRef and CGRect ?

3 Answers3