XenonUI – A Hybrid Retained/Immediate Mode UI Framework in C++ (SDL3)

I'm excited to share XenonUI, a cross-platform UI framework written in modern C++ (using SDL3 for rendering). I've been working on this for the last two years and it's currently at v0.9.0-alpha.

Why XenonUI? I started this project because I found existing cross-platform UI options were too heavy or too rigid for developing specialized desktop tools or game engine debug UIs.

The key differentiator is the Hybrid Mode approach:

Retained Mode: For complex, persistent elements like settings dialogs or configuration windows. Objects (Button, Slider) are created once and handle their own state/events. (Similar to traditional application frameworks).

Immediate Mode: For fast, lightweight components like in-game overlays or logic that needs to run every frame. Widgets are drawn and handle their logic in a single function call, perfect for visualizing real-time data. (Similar to Dear ImGui).

This lets developers choose the best paradigm per application context.

Links and Quick Start Code & Examples: [https://github.com/Sarowar-s/XenUI]

License: Apache 2.0 (Permissive)

I'm looking forward to any feedback on the C++ design, performance on different platforms, or suggestions on simplifying the API. Thanks for checking it out!