denise-winit

The desktop development and preview backend for Denise, a direct-rendering UI toolkit in Rust for embedded Linux and systems without a desktop environment.

This is not a deployment target. It exists so the core abstraction can be proven — and iterated on — without a Raspberry Pi on the desk. Shipping Denise on a desktop means shipping a compositor you did not need.

use denise::{Color, DamageTracker, Frame, InputEvent, Rect};
use denise_render::Canvas;
use denise_winit::{DeniseApp, WindowConfig, run};

struct Hello;

impl DeniseApp for Hello {
    fn update(&mut self, _events: &[InputEvent], _damage: &mut DamageTracker) {}

    fn render(&mut self, frame: &mut Frame<'_>, damage: &[Rect]) {
        let mut canvas = Canvas::new(frame);
        for region in damage {
            canvas.with_clip(*region).clear(Color::from_rgb888(0x1E1E2E));
        }
    }
}

# fn demo() {
run(WindowConfig::default(), Hello).unwrap();
# }

Why it earns its place

Because the alternative is developing blind. A backend that produces the same InputEvents and honours the same Surface contract as DRM means a panel can be written and reviewed on a laptop and then run unchanged on the hardware — and when it does not, the difference is in the backend rather than in the abstraction, which is a far smaller place to look.

It also keeps the contract honest: two independent implementations of Surface is the minimum at which "the trait describes the problem" stops being an assertion.

Runs on Linux, macOS and Windows, on winit and softbuffer — the only two dependencies in the whole workspace that are there purely for convenience.

Where this sits

Implements denise::Surface and denise::InputSource. Swap it for denise-drm plus denise-evdev to ship, usually behind one cfg in the application.

For putting a Denise panel inside an existing desktop application, this is the wrong crate — see denise-win32, denise-macos or denise-activex, which embed rather than own the window.

Status

M0 complete, and used continuously since. Part of Denise — see the repository README for the whole picture.

MIT licensed.