This Curve Editor, written by Jehee Lee in 2015, is freeware. You can use, modify, redistribute the code without restriction. This software requires python3, numpy, and glfw to be installed. I use this code mainly for teaching computer graphics and computer animation courses.

GLFW version

python spline.py

GLUT version

python spline_glut.py

[c] Toggle open/closed

[v] Toggle show/hide latent points

[d] Delete a point

[x] Delete all points

[q] Exit

[up/down arrow] in subdivision mode: level up/down

[up/down arrow] in Lagrange mode: add/remove control points

[left/right arrow] rotate control points

[1] B-spline

[2] Natural spline

[3] Catmull-Rom spline

[4] Lagrange polynomial

[5] Bezier spline

[6] Cubic B-spline subdivision

[7] Corner cutting subdivision

[8] Interpolatory subdivision