calculateCubicBezierPoint is a helper method for drawCubicBezier / drawCubicBezierPath to work. It returns a point in a section of a simple curve. To get all the points in a curve with many sections, you could modify drawCubicBezierPath to return the points instead of draw, but actually I was already experimenting with this some time ago, you can see here:
With the points of the shape you can try a triangulate algorithm, or draw lines getting the points horizontally. That is something I'm interested but didn't test yet.
There is alternative that works for now in cpp targets:
But I didn't test yet on mobile devices.
zui - Immediate Mode Graphical User interface for Haxe Kha
khasam - SAM for Kha
khamint - Kha backend for mint library
z-particles - Particle system for Kha