Kalligraph is a utility library for rendering vector graphics on the GPU.
It does the mesh generation for the technique presented by Loop and Blinn in 2005 in GPU Gems 3 (original paper, presentation).
There is a patent (US7564459B2) on using this for cubic curves until 2026... So for now this only does quadratic curves, which is enough for true type fonts and can be used to approximate cubic ones.
- Cubic to quadratic curve simplification (Works surprisingly well, but the error is quite big with the simple approach I implemented)
- Curve intersection removal by finding intersection points and generating new curves to that point.
- Curve overlap reduction by subdividing overlapping curves.
- Curve simplification by merging points that are close and reducing the order of a curve if it's higher than needed.
- Brute force polygon triangulation that mostly just works. It's slow and can run into precision issues, but other than that it can handle a lot. (I've looked at different libraries to use, but they are either only free for non commercial projects or have other restrictions. I am considering to eventually try poly2tri if my solution ends up too slow).
- Loop-Blinn based quadratic curves to triangles mesh generation.