Credits

Penpal gratefully uses the following third-party code, under MIT license:

​BezierJS by Pomax - for general Bezier magic.

​fit-curve by Aleksandr Motsjonov - for the Simplify function to optimise bezier paths.

DragSelect​ by Thibault Jan Beyer - for selecting elements in the canvas by dragging.

SweetAlert2​ by various contributors - for alerts and tooltips.