private static float cubicBezier( float t, float xy1, float xy2 ) {
		float invT = (1 - t);
		float b1 = 3 * t * (invT * invT);
		float b2 = 3 * (t * t) * invT;
		float b3 = t * t * t;
		return (b1 * xy1) + (b2 * xy2) + b3;
	}
Computes the x or y point on a cubic bezier curve for a given t value.

https://en.wikipedia.org/wiki/B%C3%A9zier_curve#Cubic_B%C3%A9zier_curves

The general cubic bezier formula is:
  x = b0*x0 + b1*x1 + b2*x2 + b3*x3
  y = b0*y0 + b1*y1 + b2*y2 + b3*y3

where:
  b0 = (1-t)^3
  b1 = 3 * t * (1-t)^2
  b2 = 3 * t^2 * (1-t)
  b3 = t^3

 x0,y0 is always 0,0 and x3,y3 is 1,1, so we can simplify to:
  x = b1*x1 + b2*x2 + b3
  y = b1*x1 + b2*x2 + b3
flatlaf-core/src/main/java/com/formdev/flatlaf/util/CubicBezierEasing.java