Retained ← Immediate Mode

Rim is an UI library that translates immediate-mode UI calls into a retained-mode UI tree. It's able to do this using a virtual DOM that diffs UI trees and applies changes to a window using a native toolkit (such as GTK, Cocoa, etc)

It's very similar to react.js, but provides a imgui-like API rather than something like JSX.

#include <stdio.h>
#include <rim.h>
int mymain(struct RimContext *ctx, void *arg) {
    int show_more = 0;
    while (rim_poll(ctx)) {
        if (im_begin_window("My Window", 500, 500)) {
            if (im_button("Button")) show_more = !show_more;
            if (show_more) im_label("Hello World");
            im_end_window();
        }
    }
    return 0;
}
int main(void) {
    return rim_start(mymain, NULL);
}

• Rim is capable of supporting multiple different UI toolkits (backends).
• currently LibUI is the only backend, but adding a Qt or wxWidgets backend would be trivial.
• LibUI backend Supports Win32 (Windows Common Controls), MacOS (Cocoa), and Linux (GTK3)

The tree builder and differ is fast enough that there should be virtually zero overhead for basic changes. (eg: text in a label changes) For more info see perf.

Rim is compiled as a static library with the backend included. On Linux, libgtk-3-dev is required.

git clone https://github.com/petabyt/libui-dev.git --depth 1 --recurse-submodules
git clone https://github.com/petabyt/rim.git --depth 1 --recurse-submodules
cd rim
cmake -G Ninja -B build -DRIM_COMPILE_DEMOS=ON CMAKE_BUILD_TYPE=Debug
cmake --build build

• Support tables
• Widget Recycler
• Support multiple sessions in one process
• A way to handle RecyclerViews/tables
• Qt backend
• Jetpack Compose backend

See why.