Resolving self-intersecting paths

[Alfie Woodland]

I'm getting to grips with paper.js by creating a simple animation tool in the browser, but I've hit an issue. In this tool brush strokes of the same colour are united into a single path, much like in flash; however, as self-intersecting paths aren't yet supported within the boolean operations of paper.js I'm left struggling to find a method to remove these intersections. Picture supplied for reference.

Is there a method within paper.js already which can deal with this case, or am I just going to have to be a little more clever with how the brush strokes are generated?

Any plans to introduce boolean operations for self-intersecting paths in the future?

Thanks!

[Péter Vívó]

try: split your path to segments and test each segments intersection by other segments, then you get all intersections points.

[Alfie Woodland]

Hey, thanks for the reply.

The only way I can think to do that is if I split the path into an array of paths each containing a single curve and then called getIntersections() for all n! cases, but even a single cubic Bézier curve can self-intersect, so I might not find all of the points. Not to mention the fact that even then there would be the issue of slicing up the path and recombining it correctly.

This problem is way over my head, honestly. I'll just work around it for now, but a method to clean up paths like this would be a really awesome addition to paper.js

[Jürg Lehni]

Hari, here another request for support of self-intersection in the boolean code. That's the same situation as the previous one, right?

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<self-intersect.png>

[Harikrishnan G.]

I think I will be able to find some time to finish it. All the required algorithms are in place now.
You can see the progress here https://groups.google.com/forum/#!topic/paperjs/bJ-e1Fu0MnU

/Hari