Question

What would be the formula to rotate a curve by the x axis in java?

Answer 1

Assuming you have the curve as an array of Points here is something like a pseudocode:

Point[] curve;

double x_max = curve[0].x, x_min = curve[0].x;
for( point : curve) {
  x_max = max(x_max, point.x);
  x_min = max(x_min, point.x);
}

for (point : curve) {
  point.x = x_max - point.x + x_min;
}

How does it work? In fact I try to mirror the curve’s normalized coordinates – that is the coordinates that the points would have if they started from x = 0 (the formula for that is point.x - x_min) and then you subtract the result from x_max so that the curve now is defined right to left instead of left to right.