Add C++20 RAII wrapper around wlroots 0.20 + scenefx

Wraps wlroots' C ABI behind owning types (Display, Backend, Compositor,
Output, XdgShell/Toplevel, Seat/Cursor/Keyboard, Scene/Node/Tree) with
wl_signal -> std::function callbacks. Links the scenefx effect engine and
ships a wlr::fx animation helper. Includes a runnable tinywl-style compositor
and a scene/blur demo.

License: AGPL-3.0-only.

include/wlr/seat.hpp

@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+#pragma once
+
+#include <functional>
+#include <xkbcommon/xkbcommon.h>
+
+#include "wlr/wlr.hpp"
+#include "wlr/display.hpp"
+#include "wlr/signals.hpp"
+#include "wlr/output.hpp"
+namespace wlr {
+
+class Cursor {
+public:
+	Cursor() : m_cursor(wlr_cursor_create()) {}
+	~Cursor() { if (m_cursor) wlr_cursor_destroy(m_cursor); }
+	Cursor(const Cursor&) = delete;
+	Cursor& operator=(const Cursor&) = delete;
+	struct wlr_cursor* raw() const { return m_cursor; }
+	explicit operator bool() const { return m_cursor != nullptr; }
+
+	void attach_output_layout(struct wlr_output_layout* layout) {
+		wlr_cursor_attach_output_layout(m_cursor, layout);
+	}
+	void attach_input_device(struct wlr_input_device* dev) {
+		wlr_cursor_attach_input_device(m_cursor, dev);
+	}
+	void warp(double x, double y) { wlr_cursor_warp(m_cursor, nullptr, x, y); }
+
+private:
+	struct wlr_cursor* m_cursor;
+};
+
+class Keyboard {
+public:
+	Keyboard(struct wlr_keyboard* kb) : m_keyboard(kb) {}
+	struct wlr_keyboard* raw() const { return m_keyboard; }
+	explicit operator bool() const { return m_keyboard != nullptr; }
+
+	void set_keymap(struct xkb_keymap* keymap) { wlr_keyboard_set_keymap(m_keyboard, keymap); }
+	void set_default_keymap() {
+		struct xkb_context* ctx = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
+		if (!ctx) return;
+		struct xkb_keymap* km = xkb_keymap_new_from_names(ctx, nullptr, XKB_KEYMAP_COMPILE_NO_FLAGS);
+		xkb_context_unref(ctx);
+		if (km) {
+			wlr_keyboard_set_keymap(m_keyboard, km);
+			xkb_keymap_unref(km);
+		}
+	}
+	void on_key(std::function<void(void*)> cb) { m_keys.connect(&m_keyboard->events.key, std::move(cb)); }
+
+private:
+	struct wlr_keyboard* m_keyboard;
+	SignalSink m_keys;
+};
+
+class Seat {
+public:
+	Seat(Display& display, const char* name)
+		: m_seat(wlr_seat_create(display.raw(), name)) {}
+	~Seat() { if (m_seat) wlr_seat_destroy(m_seat); }
+	Seat(const Seat&) = delete;
+	Seat& operator=(const Seat&) = delete;
+
+	struct wlr_seat* raw() const { return m_seat; }
+	explicit operator bool() const { return m_seat != nullptr; }
+
+	void set_capabilities(uint32_t caps) { wlr_seat_set_capabilities(m_seat, caps); }
+	void set_keyboard(Keyboard& kb) { wlr_seat_set_keyboard(m_seat, kb.raw()); }
+	void keyboard_notify_key(uint32_t time, uint32_t keycode, enum wl_keyboard_key_state state) {
+		wlr_seat_keyboard_notify_key(m_seat, time, keycode, state);
+	}
+	void pointer_notify_motion(uint32_t time, double sx, double sy) {
+		wlr_seat_pointer_notify_motion(m_seat, time, sx, sy);
+	}
+	uint32_t pointer_notify_button(uint32_t time, uint32_t button, enum wl_pointer_button_state state) {
+		return wlr_seat_pointer_notify_button(m_seat, time, button, state);
+	}
+	void pointer_notify_axis(uint32_t time, enum wl_pointer_axis axis, double value, int value_discrete, enum wl_pointer_axis_source source) {
+		wlr_seat_pointer_notify_axis(m_seat, time, axis, value, value_discrete, source,
+			WL_POINTER_AXIS_RELATIVE_DIRECTION_IDENTICAL);
+	}
+	void pointer_notify_frame() { wlr_seat_pointer_notify_frame(m_seat); }
+
+private:
+	struct wlr_seat* m_seat;
+};
+
+}