adamwulf / ClippingBezier

ClippingBezier calculates intersection points, paths, and shapes between two UIBezierPaths
http://getlooseleaf.com/opensource/
MIT License
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Can not find intersection of two path #30

Open iOSjhx opened 11 months ago

iOSjhx commented 11 months ago

First of all thank you for your ClippingBezier library, it's very useful for me. I encountered a problem,I can't find the intersection of two path, but they do.

first path is unclosed:

    UIBezierPath * path1 = [UIBezierPath bezierPath];
    [path1 moveToPoint:CGPointMake(400, 364)];
    [path1 addLineToPoint:CGPointMake(401.5078817412837, 369.1644648236025)];
    [path1 addLineToPoint:CGPointMake(402, 371.5)];
    [path1 addLineToPoint:CGPointMake(421.5, 371.5)];

second path is closed:

    UIBezierPath *path2 = [UIBezierPath bezierPath];
    [path2 moveToPoint:CGPointMake(390.4289321881345, 369.0710678118655)];
    [path2 addLineToPoint:CGPointMake(390.9289321881345, 369.5710678118655)];
    [path2 addCurveToPoint:CGPointMake(405.0710678118655, 369.5710678118655) controlPoint1:CGPointMake(394.8341751056472, 373.4763107293782) controlPoint2:CGPointMake(401.1658248943528, 373.4763107293782)];
    [path2 addCurveToPoint:CGPointMake(405.0710678118655, 355.4289321881345) controlPoint1:CGPointMake(408.9763107293782, 365.6658248943528) controlPoint2:CGPointMake(408.9763107293782, 359.3341751056472)];
    [path2 addLineToPoint:CGPointMake(404.5710678118655, 354.9289321881345)];
    [path2 addCurveToPoint:CGPointMake(390.4289321881345, 354.9289321881345) controlPoint1:CGPointMake(400.6658248943528, 351.0236892706218) controlPoint2:CGPointMake(394.3341751056472, 351.0236892706218)];
    [path2 addCurveToPoint:CGPointMake(390.4289321881345, 369.0710678118655) controlPoint1:CGPointMake(386.5236892706218, 358.8341751056472) controlPoint2:CGPointMake(386.5236892706218, 365.1658248943528)];
    [path2 closePath];

use method : [path1 findIntersectionsWithClosedPath:path2 andBeginsInside:nil];

screenShot My English is poor, I don't know if you understand what I'm saying, I need your help, thank you .

adamwulf commented 11 months ago

Thanks for sending in this error case - it's very helpful for me to track down bugs with test cases like this.

Unfortunately, I don't have a quick fix for you, but I do have some workarounds that might help. sometimes the algorithm finds more consistently with large paths, so you can try scaling the paths by 100x → find intersections → scale intersections down by 1/100. Anther option is to bump one of the paths by a very small amount, translating it by a very small epsilon → find intersections.