F = (0, 1)
f = Function(If[x < 0.0, 0.0, If[x ≟ 0.0, 1.0, 2.0]], -5.0, 5.0)

Tool: Orthocentre
Cliquer sur les trois sommets du triangle
Input: A, B, C
Output: D

a = Line(B, C)
b = Line(A, B)
c = OrthogonalLine(C, b)
d = OrthogonalLine(A, a)
D = Intersect(c, d)