XenonUI: Revolutionizing Cross-Platform UI Development with Hybrid Modes

In a landscape dominated by heavyweight UI toolkits, a new contender has emerged: XenonUI, a cross-platform UI framework crafted in modern C++ and powered by SDL3 for rendering. Announced by its creator, Sarowar, after a year of development, the project has reached v0.9.0-alpha and targets developers building specialized desktop tools or game engine debug UIs. Unlike traditional frameworks that force a single paradigm, XenonUI's standout feature is its Hybrid Mode, seamlessly blending retained and immediate rendering styles to offer unparalleled flexibility.

The Problem with Existing UI Frameworks

Existing cross-platform UI options often fall short for niche applications. Many are either too bloated for lightweight tools or too inflexible for real-time needs like in-game overlays. Sarowar started XenonUI to fill this void, prioritizing performance and adaptability over feature bloat.

"I found existing cross-platform UI options were too heavy or too rigid for developing specialized desktop tools or game engine debug UIs."

This quote from the project's announcement captures the motivation behind XenonUI, resonating with C++ developers frustrated by frameworks that compromise on speed or ease of integration into performance-sensitive environments like game engines.

Hybrid Mode: The Game-Changer

At the heart of XenonUI lies its Hybrid Mode, allowing developers to mix two proven UI paradigms:

Retained Mode

For complex, persistent UI elements such as settings dialogs or configuration windows:
- Objects like Button or Slider are instantiated once.
- They autonomously manage their own state and events, akin to traditional application frameworks (e.g., Qt or GTK).

Immediate Mode

Ideal for fast, lightweight components like in-game overlays or per-frame logic:
- Widgets are drawn and handle logic in a single function call.
- Perfect for real-time data visualization, mirroring the efficiency of libraries like Dear ImGui.

This duality lets developers select the optimal approach per context, reducing overhead while maintaining expressiveness. For instance, a game engine could use immediate mode for dynamic debug panels while employing retained mode for static config screens—without framework-wide compromises.

// Example pseudocode for Hybrid Mode usage
// Retained: Create once
auto button = xenon::Button("Save").onClick([](){ saveConfig(); });

// Immediate: Call every frame
xenon::Slider("Volume", &volume, 0.0f, 1.0f);

Such flexibility could streamline workflows for C++ developers in gaming, scientific visualization, or embedded systems, where every millisecond counts.

Technical Details and Accessibility

Built on SDL3, XenonUI ensures robust cross-platform support—Windows, Linux, macOS, and beyond. The source code, examples, and documentation reside on GitHub, released under the permissive Apache 2.0 license. Currently in alpha, it's ripe for early adopters to test C++ design choices, platform performance, and API ergonomics.

Sarowar invites feedback: "I'm looking forward to any feedback on the C++ design, performance on different platforms, or suggestions on simplifying the API."

Implications for C++ Developers

XenonUI arrives at a pivotal moment for C++ UI development. With rising demand for performant, embeddable UIs in tools like Unreal Engine plugins or real-time simulators, a lightweight hybrid framework could gain traction. If it matures, XenonUI might challenge incumbents by offering a middle ground between ImGui's simplicity and full-featured toolkits' complexity—potentially accelerating prototyping for high-performance applications.

As the community engages with this alpha release, XenonUI stands poised to influence how C++ teams approach cross-platform interfaces, blending the best of both UI worlds in a single, efficient package.