Improve curve offsetting

[bourgesl]

Ill-conditioned quad or cubic curves can have 1 to 5 curvature maxima... so the current basic approach in Stroker is really approximative for thick curves > 5px ...

In branch better-curves, new adaptative algorithms achieve high quality, but its performance can be improved for general use.

See https://github.com/bourgesl/marlin-renderer/tree/better-curves

EA releases:
https://github.com/bourgesl/marlin-renderer/releases/tag/v1_0_0_EA_3

This is the Marlin-renderer 1.0.0 Early Access release 2 release providing better curve rendering i.e. stroke width along the quad / cubic curves is more accurate.
See screenshots of improvements:

https://raw.githubusercontent.com/bourgesl/bourgesl.github.io/master/marlin-better-curves/computeOffsetCubic_fixed.png

https://raw.githubusercontent.com/bourgesl/bourgesl.github.io/master/marlin-better-curves/computeOffsetCubic_bug.png

more screenshots: at https://github.com/bourgesl/bourgesl.github.io/tree/master/marlin-better-curves

[bourgesl]

See this bug report in 2021.11 on jdk11 & 17:
https://bugs.openjdk.java.net/browse/JDK-8277574

[bourgesl]

To fix marlin's bezier quad or cubic issues, I found how to solve accurately:

• quadratics: http://people.eecs.berkeley.edu/~wkahan/Qdrtcs.pdf
• cubics: http://people.eecs.berkeley.edu/~wkahan/Math128/Cubic.pdf

So happy !

See
http://people.eecs.berkeley.edu/~wkahan/Math128/