TL;DR AffineUI is a DearImgui style GPU accellerated html5 UI engine you can easily just drop into a project. It gives you what you get with Electron and JS, but with pure C++ and in only 2-3MB of space.  
  
I thought this might be useful to C++ engineers working on games, graphics, content in C++ looking for a good lightweight html5 Electron style UI engine.

I built AffineUI with the idea that it was a small zero-dep drop in lib that could be a cross between DearIMGUI and Electron. A UI engine that was a full featured GPU accelerated html5 rendering engine that understood all of HTML5 and CSS, but also was a (fairly) small single file header style drop in that just worked. With NO javascript - just pure C++.

AffineUI is a full DOM and web page renderer that understands html and CSS, but it also has a full Gradio style UI framework that lets you just program the UI of your app like you always have, with buttons, list boxes, menus, docking panels, floating panels, etc. You can write an entire app without touching html5 or CSS, but all it's power is there working underneath.   
  
This means you can grab entire designs from Claude Design and bring them as-is to your C++ code, avoiding Electron and javascript and GBs of chromium. Just have Claude design your UI, drag the files into your project, and then have your agents build the C++ version of it with AffineUI with the same CSS, but all 100% in C++ instead of javascript.  


AffineUI is very fast, and pretty small. It's not nearly as small as DearImgui but it's only a few MB optimized, and it renders optimally and only updates what needs to be draw, and only rendering when something animates or changes. When a screen is not animating, it takes 0 cpu/gpu time. But it's capable of rendering pretty complex anims and even layout at 60hz, 120hz, or higher.

Internally AffineUI leverages some excellent projects like Lexbor, NanoVG, SokolGFX to do what it does, with those symbols all static in the single .cpp file not leaking into your app. It's built on a pretty solid foundation.

Right now it's tested on Linux (Ubuntu flavors), Mac, Windows and runs in GL, DX11, Metal (with I think Vulcan experimental in the Sokol GFX core I'm using). I also have a python wrapper, rust, and C# .net bindings in [crates.io](http://crates.io) and nuget, pypi. It's well tested but I'd still consider the lib "alpha" status at this point. 

It's just a single .cpp and a single .h you drop into your project, and only adds symbols from it's official api. It runs perfectly fine with that and just a main.cpp. Also if your project is already running with SDL2 or sokol\_app it can just drop in, or you can also write your own bespoke window manager bridge.

Feel free to kick the tires. File bug reports, or contribute if you want. MIT licensed and completely free.

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HelloWorld.cpp for AffineUI - you just need to add affineui.cpp and affineui.h for this to run on any platform.

    #include "affineui.h"
    
    int main() {
        affineui::View view{affineui::ViewTheme::Decius};
        view.begin();
        view.heading(1, "Hello from C++");
        view.paragraph("AffineUI — native HTML/CSS, no browser, no JS.");
        view.button("Click me", /*primary=*/true, "go")
            .on_click([] { std::puts("clicked!"); });
        view.end();
    
        affineui::App::Config cfg;
        cfg.title  = "Hello";
        cfg.width  = 720;
        cfg.height = 480;
        affineui::App app{cfg};
        app.load_view(view);
        return app.run();
    }



  


AffineUI - a two file zero-dep gpu html5 UI engine for C++20.