New Dear ImGUI font system (Dear ImGUI 1.92)

[BrunoLevy]

Since v. 1.92 (June 2025), Dear ImGUI now has a dynamic font atlas system (no need to pre-build the fonts with pre-defined sizes). This will introduce a couple of changes (mostly in the Application class, and this will make it simpler).

References:

• Dear ImGUI v1.92 release notes
• Font system doc
• Discussions

[BrunoLevy]

Nearly there ! Just one thing: TextEditor display is garbaged (I suspect xadvance not computed properly).

[BrunoLevy]

Make sure that everything works:

• Linux (seems to be OK)
• Windows (seems to be OK)
• Emscripten -> broken (problem in CMake that tries to link X11) -> fixed
• Mac -> works, but fonts are too large on Retina displays (they have the correct size on non-Retina displays)
• Android