Imagine you have a completely normal four-point bezier curve (two points and two control points) created using curveToPoint:controlPoint1:controlPoint2: in your cocoa application:
How do you find points (and the tangents), along the curve?
Later: for a complete, simplified, solution based on Michal's answer below, click to:
Find the tangent of a point on a cubic bezier curve (on an iPhone)
And just copy and paste the code from: https://stackoverflow.com/a/31317254/294884
Best Answer
There's some simple math behind calculating the positions, you can read about it in every paper discussing Bézier curves, even on wikipedia. Anyway, I can relate to everybody who's in trouble to actually implement it in code, so I wrote this sample UIView as it's probably the easiest way to get you started.
This is what I get: