# NeferGUI

A pure-Go GUI renderer for Linux: build your view from the current model, style it with CSS, and draw it with Vulkan into DMA-BUF buffers. Controls return events during the view call. No cgo required.

NeferGUI imports no Wayland library. Your application owns the Wayland client (connection, surface, linux-dmabuf feedback, buffer import, seat events) and drives a `Renderer`; [github.com/bnema/neferclient](https://github.com/bnema/neferclient) is a client toolkit built for this. The two do not import each other: the application copies plain fields between them.

> [!WARNING]
> **Early development.** No release yet. Expect bugs and breaking changes. Platform accessibility is not connected.

## A small example

The view is plain Go. The model type is yours.

```go
type Model struct{ Count int }

view := func(f *nefergui.Frame, m *Model) {
	root := f.Root().Column()
	root.Text("Hello, Wayland!")
	if root.Button("Count", nefergui.Key("count")).Activated() {
		m.Count++
	}
	root.Text(fmt.Sprintf("Clicked %d times", m.Count))
}
```

The client loop, on one owner goroutine:

```go
r, err := nefergui.NewRenderer(nefergui.RendererConfig{MainDevice: dev, Formats: formats})
r.Resize(320, 200, 1)          // on configure and scale changes
r.Input(&nefergui.Input{...})  // for each pointer, key and focus event

var out nefergui.Output
if ok, err := r.Render(&out, &model, view); ok && err == nil {
	// import out.Planes as a wl_buffer when out.NewBuffer, attach with the
	// acquire/release points, commit
}
r.Released(buffer) // when out.ReleaseFD becomes readable
```

`RendererConfig.Styles` loads your own CSS; default styles work without it. See `ExampleRenderer` and [runtime](docs/runtime.md) for the full contract.

## Demo

[`examples/demo`](examples/demo) is a document workspace (toolbar, document list, text editor, properties pane, light and dark themes) in a Wayland window, using neferclient as the client. It lives in its own module, so NeferGUI does not depend on neferclient, and it always builds against the NeferGUI code in this checkout:

```sh
cd examples && go run ./demo
```

## Requirements

Go 1.27, `libvulkan.so.1` and usable fonts. The GPU must export DMA-BUF and support DRM syncobj timelines (kernel 6.6 or later for eventfd waits). The compositor, reached through your Wayland client, must offer linux-dmabuf and linux-drm-syncobj; fractional scaling also needs viewporter. No X11 or software-rendering fallback.

```sh
go get github.com/bnema/nefergui
```

## Documentation

- [Controls](docs/controls.md) and [layout](docs/layout.md)
- [CSS properties and limitations](docs/css.md)
- [Runtime requirements and behavior](docs/runtime.md) and [troubleshooting](docs/troubleshooting.md)
- [Performance](docs/performance.md)
- [Architecture decisions](docs/adr)

## License

[GNU GPL v3](LICENSE). Third-party code and test fonts retain their own licenses and attribution.