1# neferclient
2
3A Wayland client toolkit library for Go: connection, outputs, surface roles, seat and DMA-BUF presentation. It does not render and holds no application policy. No cgo required.
4
5> [!WARNING]
6> **Early development.** No release yet. Expect bugs and breaking changes.
7
8## Requirements
9
10- Linux, kernel 6.6 or newer (DRM syncobj eventfd).
11- A compositor advertising `zwp_linux_dmabuf_v1` (v4) and `wp_linux_drm_syncobj_manager_v1`.
12- `libxkbcommon` at runtime for keyboard input.
13
14## Usage
15
16The library does not render. The `examples` module pairs it with [NeferGUI](https://github.com/bnema/nefergui) (a pure graphics library with no Wayland code); the two never import each other, and the examples copy plain fields between them. The loop runs on one owner goroutine:
17
18```go
19conn, err := neferclient.Connect(ctx, "")
20if err != nil {
21	return fmt.Errorf("connect: %w", err)
22}
23defer conn.Close()
24surf, err := conn.NewLayerSurface(neferclient.LayerConfig{Level: neferclient.LayerTop, Width: 240, Height: 90})
25if err != nil {
26	return fmt.Errorf("layer surface: %w", err)
27}
28for {
29	select {
30	case <-conn.Wake():
31		if err := conn.Dispatch(handler); err != nil { // Configure, FeedbackDone, Frame, Pointer, Key, FDReady...
32			return fmt.Errorf("dispatch: %w", err)
33		}
34	case <-ctx.Done():
35		return nil
36	}
37	// render with NeferGUI, then surf.ImportBuffer / surf.ImportTimeline / surf.Present
38}
39```
40
41### Popups
42
43`Conn.NewPopup` creates an `xdg_popup` on a layer surface, a toplevel or another popup: a menu or tooltip placed relative to an anchor rectangle of its parent. With `Grab` the popup takes the keyboard and the compositor dismisses it on a click outside; the grab needs the `PointerEvent.Serial` of the button press that opened it. The compositor can dismiss a popup at any time, so a handler must implement `PopupDone` (embedded `NopHandler` ignores it) and close the popup; close popups before their parent.
44
45```go
46func (h *handler) Pointer(ev *neferclient.PointerEvent) {
47	if ev.Kind != neferclient.PointerButton || !ev.Pressed {
48		return
49	}
50	popup, err := h.conn.NewPopup(neferclient.PopupConfig{
51		Parent: h.bar, // a layer surface
52		Place: neferclient.PopupPlacement{
53			Anchor: neferclient.Rect{X: 100, Y: 0, Width: 24, Height: 30}, // on the parent, logical px
54			Edge:   neferclient.EdgeBottom, Gravity: neferclient.EdgeBottomRight,
55			Adjust: neferclient.AdjustSlideX | neferclient.AdjustFlipY,
56			Width:  200, Height: 120,
57		},
58		Grab: true, Serial: ev.Serial,
59	})
60	if err != nil {
61		h.err = err
62		return
63	}
64	h.popup = popup // presentable after Configure, like any surface
65}
66
67func (h *handler) PopupDone(id neferclient.SurfaceID) {
68	if h.popup != nil && h.popup.ID() == id {
69		h.err = h.popup.Close()
70		h.popup = nil
71	}
72}
73```
74
75`Surface.Reposition` moves a mapped popup (`xdg_wm_base` version 3).
76
77- [`examples/layer`](examples/layer): a layer surface with a counter button.
78- [`examples/lock`](examples/lock): a session lock with a masked password field. It is a demo and authenticates nothing; read its header before running it.
79
80Run them against a compositor with `cd examples && go run ./layer`. `make examples-check` builds, vets and lints them; the headless test needs a NeferWL binary: `cd examples && NEFERCLIENT_HEADLESS=/usr/sbin/neferwl go test -run Headless ./...`.
81
82## License
83
84MIT