please implement an FLTK-based backend

I am new to polyscope and per my initial evaluation, it looks really great for use as a 3d visualization tool in my projects.

However, I am heavily invested in using the GUI toolkit FLTK for UI's in my current code.

Could you please implement an FLTK backend in addition to the GLFW + ImGUI one you already provide? It already provides a wrapper class for opengl windows, called FL_Gl_Window. Moreover, it's rich set of GUI widgets (buttons, slider, menus, etc.) can be used anywhere on that window (meaning ImGUI is not needed).

The released version of FLTK I use is 1.4 although I also use the "bleeding edge" version 1.5, so either works fine for me. Both are available as source repos on github.

Thank you for considering this!

Paul

Inizia leggendo il backend GLFW + ImGui esistente di Polyscope e la documentazione di FLTK FL_Gl_Window. Determina come un backend FLTK si integrerebbe con l’attuale modello di viewer e widget. Il lavoro è considerato completato quando è disponibile un backend per finestre OpenGL basato su FLTK insieme al backend esistente e i widget FLTK possono essere utilizzati nella finestra.