Dear ImGui is a C++ immediate-mode graphical user interface library for developers building tools, debug interfaces, game editors, and lightweight desktop interfaces....
Pros
- Immediate-mode API is fast to integrate into existing C++ applications
- MIT license permits commercial and closed-source use
- Strong support for developer tools, debugging panels, and game-engine interfaces
Cons
- Less suited than Qt or GTK for traditional end-user desktop applications
- Requires platform and renderer backends instead of shipping as a complete GUI stack
- C++-focused API offers less convenience for developers using other languages
Free, open source
