layer shell initial attempt

Makefile

@@ -23,12 +23,22 @@ xdg-shell-protocol.c:
 
 xdg-shell-protocol.o: xdg-shell-protocol.h
 
+wlr-layer-shell-unstable-v1-protocol.h:
+	$(WAYLAND_SCANNER) server-header \
+		protocols/wlr-layer-shell-unstable-v1.xml $@
+
+wlr-layer-shell-unstable-v1-protocol.c:
+	$(WAYLAND_SCANNER) private-code \
+		protocols/wlr-layer-shell-unstable-v1.xml $@
+
+wlr-layer-shell-unstable-v1-protocol.o: wlr-layer-shell-unstable-v1-protocol.h
+
 config.h: | config.def.h
 	cp config.def.h $@
 
-dwl.o: config.h xdg-shell-protocol.h
+dwl.o: config.h xdg-shell-protocol.h wlr-layer-shell-unstable-v1-protocol.h
 
-dwl: xdg-shell-protocol.o
+dwl: xdg-shell-protocol.o wlr-layer-shell-unstable-v1-protocol.o
 
 clean:
 	rm -f dwl *.o xdg-shell-protocol.h xdg-shell-protocol.c

dwl.c

@@ -19,6 +19,7 @@
 #include <wlr/types/wlr_export_dmabuf_v1.h>
 #include <wlr/types/wlr_gamma_control_v1.h>
 #include <wlr/types/wlr_input_device.h>
+#include <wlr/types/wlr_layer_shell_v1.h>
 #include <wlr/types/wlr_keyboard.h>
 #include <wlr/types/wlr_matrix.h>
 #include <wlr/types/wlr_output.h>
@@ -128,6 +129,19 @@ typedef struct {
 	struct wl_listener destroy;
 } Keyboard;
 
+typedef struct {
+	struct wlr_layer_surface_v1 *layer_surface;
+	struct wl_list link;
+
+	struct wl_listener destroy;
+	struct wl_listener map;
+	struct wl_listener unmap;
+	struct wl_listener surface_commit;
+
+	struct wlr_box geo;
+	enum zwlr_layer_shell_v1_layer layer;
+} Layer;
+
 typedef struct {
 	const char *symbol;
 	void (*arrange)(Monitor *);
@@ -140,6 +154,7 @@ struct Monitor {
 	struct wl_listener destroy;
 	struct wlr_box m;      /* monitor area, layout-relative */
 	struct wlr_box w;      /* window area, layout-relative */
+	struct wl_list layers[4]; // Layer::link
 	const Layout *lt[2];
 	unsigned int seltags;
 	unsigned int sellt;
@@ -175,21 +190,30 @@ struct render_data {
 
 /* function declarations */
 static void applybounds(Client *c, struct wlr_box *bbox);
+static void applyexclusive(struct wlr_box *usable_area, uint32_t anchor,
+		int32_t exclusive, int32_t margin_top, int32_t margin_right,
+		int32_t margin_bottom, int32_t margin_left);
 static void applyrules(Client *c);
 static void arrange(Monitor *m);
+static void arrangelayer(Monitor *m, struct wl_list *list,
+		struct wlr_box *usablearea, bool exclusive);
+static void arrangelayers(Monitor *m);
 static void axisnotify(struct wl_listener *listener, void *data);
 static void buttonpress(struct wl_listener *listener, void *data);
 static void chvt(const Arg *arg);
 static void cleanup(void);
 static void cleanupkeyboard(struct wl_listener *listener, void *data);
 static void cleanupmon(struct wl_listener *listener, void *data);
+static void commitlayernotify(struct wl_listener *listener, void *data);
 static void commitnotify(struct wl_listener *listener, void *data);
 static void createkeyboard(struct wlr_input_device *device);
 static void createmon(struct wl_listener *listener, void *data);
 static void createnotify(struct wl_listener *listener, void *data);
+static void createlayer(struct wl_listener *listener, void *data);
 static void createpointer(struct wlr_input_device *device);
 static void createxdeco(struct wl_listener *listener, void *data);
 static void cursorframe(struct wl_listener *listener, void *data);
+static void destroylayernotify(struct wl_listener *listener, void *data);
 static void destroynotify(struct wl_listener *listener, void *data);
 static void destroyxdeco(struct wl_listener *listener, void *data);
 static Monitor *dirtomon(int dir);
@@ -204,6 +228,7 @@ static int keybinding(uint32_t mods, xkb_keysym_t sym);
 static void keypress(struct wl_listener *listener, void *data);
 static void keypressmod(struct wl_listener *listener, void *data);
 static void killclient(const Arg *arg);
+static void maplayernotify(struct wl_listener *listener, void *data);
 static void maprequest(struct wl_listener *listener, void *data);
 static void monocle(Monitor *m);
 static void motionabsolute(struct wl_listener *listener, void *data);
@@ -236,7 +261,9 @@ static void tile(Monitor *m);
 static void togglefloating(const Arg *arg);
 static void toggletag(const Arg *arg);
 static void toggleview(const Arg *arg);
+static void unmaplayer(Layer *layer);
 static void unmapnotify(struct wl_listener *listener, void *data);
+static void unmaplayernotify(struct wl_listener *listener, void *data);
 static void view(const Arg *arg);
 static Client *xytoclient(double x, double y);
 static Monitor *xytomon(double x, double y);
@@ -255,6 +282,7 @@ static struct wl_list fstack;  /* focus order */
 static struct wl_list stack;   /* stacking z-order */
 static struct wl_list independents;
 static struct wlr_xdg_decoration_manager_v1 *xdeco_mgr;
+static struct wlr_layer_shell_v1 *layer_shell;
 
 static struct wlr_cursor *cursor;
 static struct wlr_xcursor_manager *cursor_mgr;
@@ -280,6 +308,7 @@ static struct wl_listener new_input = {.notify = inputdevice};
 static struct wl_listener new_output = {.notify = createmon};
 static struct wl_listener new_xdeco = {.notify = createxdeco};
 static struct wl_listener new_xdg_surface = {.notify = createnotify};
+static struct wl_listener new_layer_shell_surface = {.notify = createlayer};
 static struct wl_listener request_cursor = {.notify = setcursor};
 static struct wl_listener request_set_psel = {.notify = setpsel};
 static struct wl_listener request_set_sel = {.notify = setsel};
@@ -322,6 +351,71 @@ applybounds(Client *c, struct wlr_box *bbox)
 		c->geom.y = bbox->y;
 }
 
+void
+applyexclusive(struct wlr_box *usable_area,
+		uint32_t anchor, int32_t exclusive,
+		int32_t margin_top, int32_t margin_right,
+		int32_t margin_bottom, int32_t margin_left) {
+	struct {
+		uint32_t singular_anchor;
+		uint32_t anchor_triplet;
+		int *positive_axis;
+		int *negative_axis;
+		int margin;
+	} edges[4];
+
+	if (exclusive <= 0)
+		return;
+
+	// Top
+	edges[0].singular_anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP;
+	edges[0].anchor_triplet =
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT |
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP;
+	edges[0].positive_axis = &usable_area->y;
+	edges[0].negative_axis = &usable_area->height;
+	edges[0].margin = margin_top;
+	// Bottom
+	edges[1].singular_anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM;
+	edges[1].anchor_triplet =
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT |
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM;
+	edges[1].positive_axis = NULL;
+	edges[1].negative_axis = &usable_area->height;
+	edges[1].margin = margin_bottom;
+	// Left
+	edges[2].singular_anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT;
+	edges[2].anchor_triplet =
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT |
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP |
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM;
+	edges[2].positive_axis = &usable_area->x;
+	edges[2].negative_axis = &usable_area->width;
+	edges[2].margin = margin_left;
+	// Right
+	edges[3].singular_anchor = ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT;
+	edges[3].anchor_triplet =
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP |
+		ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM;
+	edges[3].positive_axis = NULL;
+	edges[3].negative_axis = &usable_area->width;
+	edges[3].margin = margin_right;
+
+	for (size_t i = 0; i < LENGTH(edges); ++i) {
+		if ((anchor  == edges[i].singular_anchor || anchor == edges[i].anchor_triplet)
+				&& exclusive + edges[i].margin > 0) {
+			if (edges[i].positive_axis)
+				*edges[i].positive_axis += exclusive + edges[i].margin;
+			if (edges[i].negative_axis)
+				*edges[i].negative_axis -= exclusive + edges[i].margin;
+			break;
+		}
+	}
+}
+
 void
 applyrules(Client *c)
 {
@@ -373,6 +467,152 @@ arrange(Monitor *m)
 	/* XXX recheck pointer focus here... or in resize()? */
 }
 
+void
+arrangelayer(Monitor *m, struct wl_list *list, struct wlr_box *usable_area, bool exclusive)
+{
+	Layer *layer;
+	struct wlr_box full_area = { 0 };
+	wlr_output_effective_resolution(m->wlr_output,
+			&full_area.width, &full_area.height);
+
+	wl_list_for_each(layer, list, link) {
+		struct wlr_layer_surface_v1 *layer_surface = layer->layer_surface;
+		struct wlr_layer_surface_v1_state *state = &layer_surface->current;
+		struct wlr_box bounds;
+		struct wlr_box box = {
+			.width = state->desired_width,
+			.height = state->desired_height
+		};
+		const uint32_t both_horiz = ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT
+			| ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT;
+		const uint32_t both_vert = ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP
+			| ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM;
+
+		if (exclusive != (state->exclusive_zone > 0))
+			continue;
+
+		bounds = state->exclusive_zone == -1 ? full_area : *usable_area;
+
+		// Horizontal axis
+		if ((state->anchor & both_horiz) && box.width == 0) {
+			box.x = bounds.x;
+			box.width = bounds.width;
+		} else if ((state->anchor & ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT)) {
+			box.x = bounds.x;
+		} else if ((state->anchor & ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT)) {
+			box.x = bounds.x + (bounds.width - box.width);
+		} else {
+			box.x = bounds.x + ((bounds.width / 2) - (box.width / 2));
+		}
+		// Vertical axis
+		if ((state->anchor & both_vert) && box.height == 0) {
+			box.y = bounds.y;
+			box.height = bounds.height;
+		} else if ((state->anchor & ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP)) {
+			box.y = bounds.y;
+		} else if ((state->anchor & ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM)) {
+			box.y = bounds.y + (bounds.height - box.height);
+		} else {
+			box.y = bounds.y + ((bounds.height / 2) - (box.height / 2));
+		}
+		// Margin
+		if ((state->anchor & both_horiz) == both_horiz) {
+			box.x += state->margin.left;
+			box.width -= state->margin.left + state->margin.right;
+		} else if ((state->anchor & ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT)) {
+			box.x += state->margin.left;
+		} else if ((state->anchor & ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT)) {
+			box.x -= state->margin.right;
+		}
+		if ((state->anchor & both_vert) == both_vert) {
+			box.y += state->margin.top;
+			box.height -= state->margin.top + state->margin.bottom;
+		} else if ((state->anchor & ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP)) {
+			box.y += state->margin.top;
+		} else if ((state->anchor & ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM)) {
+			box.y -= state->margin.bottom;
+		}
+		if (box.width < 0 || box.height < 0) {
+			wlr_layer_surface_v1_close(layer_surface);
+			continue;
+		}
+		layer->geo = box;
+
+		applyexclusive(usable_area, state->anchor, state->exclusive_zone,
+				state->margin.top, state->margin.right,
+				state->margin.bottom, state->margin.left);
+		wlr_layer_surface_v1_configure(layer_surface, box.width, box.height);
+	}
+}
+
+void
+arrangelayers(Monitor *m)
+{
+	struct wlr_box usable_area = { 0 };
+	uint32_t layers_above_shell[] = {
+		ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY,
+		ZWLR_LAYER_SHELL_V1_LAYER_TOP,
+	};
+	size_t nlayers = LENGTH(layers_above_shell);
+	Layer *layer, *topmost = NULL;
+
+	wlr_output_effective_resolution(m->wlr_output,
+			&usable_area.width, &usable_area.height);
+
+	// Arrange exclusive surfaces from top->bottom
+	arrangelayer(m, &m->layers[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY],
+			&usable_area, true);
+	arrangelayer(m, &m->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP],
+			&usable_area, true);
+	arrangelayer(m, &m->layers[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM],
+			&usable_area, true);
+	arrangelayer(m, &m->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND],
+			&usable_area, true);
+
+	/* XXX does wlr_output_effective_resolution return the same dimensions
+	   as wlr_output_layout_get_box which is used to set m->m ? */
+	if (memcmp(&usable_area, &m->w, sizeof(struct wlr_box))) {
+		memcpy(&m->w, &usable_area, sizeof(struct wlr_box));
+		arrange(m);
+	}
+
+	// Arrange non-exlusive surfaces from top->bottom
+	arrangelayer(m, &m->layers[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY],
+			&usable_area, false);
+	arrangelayer(m, &m->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP],
+			&usable_area, false);
+	arrangelayer(m, &m->layers[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM],
+			&usable_area, false);
+	arrangelayer(m, &m->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND],
+			&usable_area, false);
+
+	// Find topmost keyboard interactive layer, if such a layer exists
+	for (size_t i = 0; i < nlayers; ++i) {
+		wl_list_for_each_reverse(layer,
+				&m->layers[layers_above_shell[i]], link) {
+			if (layer->layer_surface->current.keyboard_interactive &&
+					layer->layer_surface->mapped) {
+				topmost = layer;
+				break;
+			}
+		}
+		if (topmost) {
+			break;
+		}
+	}
+
+	if (topmost)
+		wlr_seat_keyboard_notify_enter(seat,
+				topmost->layer_surface->surface, NULL, 0, NULL);
+	else if (
+		seat->keyboard_state.focused_surface
+		&& wlr_surface_is_layer_surface(seat->keyboard_state.focused_surface)
+		&& !wlr_layer_surface_v1_from_wlr_surface(seat->keyboard_state.focused_surface)
+			->current.keyboard_interactive
+	)
+		wlr_seat_keyboard_notify_clear_focus(seat);
+}
+
 void
 axisnotify(struct wl_listener *listener, void *data)
 {
@@ -470,6 +710,28 @@ cleanupmon(struct wl_listener *listener, void *data)
 	free(m);
 }
 
+void
+commitlayernotify(struct wl_listener *listener, void *data)
+{
+	Layer *layer = wl_container_of(listener, layer, surface_commit);
+	struct wlr_layer_surface_v1 *layer_surface = layer->layer_surface;
+	struct wlr_output *wlr_output = layer_surface->output;
+	Monitor *m;
+
+	if (!wlr_output)
+		return;
+
+	m = wlr_output->data;
+	arrangelayers(m);
+
+	if (layer->layer != layer_surface->current.layer) {
+		wl_list_remove(&layer->link);
+		wl_list_insert(&m->layers[layer_surface->current.layer],
+			&layer->link);
+		layer->layer = layer_surface->current.layer;
+	}
+}
+
 void
 commitnotify(struct wl_listener *listener, void *data)
 {
@@ -522,6 +784,7 @@ createmon(struct wl_listener *listener, void *data)
 	struct wlr_output *wlr_output = data;
 	Monitor *m;
 	const MonitorRule *r;
+	size_t len;
 
 	/* The mode is a tuple of (width, height, refresh rate), and each
 	 * monitor supports only a specific set of modes. We just pick the
@@ -567,6 +830,11 @@ createmon(struct wl_listener *listener, void *data)
 	 */
 	wlr_output_layout_add_auto(output_layout, wlr_output);
 	sgeom = *wlr_output_layout_get_box(output_layout, NULL);
+
+	len = LENGTH(m->layers);
+	for (size_t i = 0; i < len; ++i) {
+		wl_list_init(&m->layers[i]);
+	}
 }
 
 void
@@ -600,6 +868,48 @@ createnotify(struct wl_listener *listener, void *data)
 	wl_signal_add(&xdg_surface->events.destroy, &c->destroy);
 }
 
+void
+createlayer(struct wl_listener *listener, void *data)
+{
+	struct wlr_layer_surface_v1 *layer_surface = data;
+	Layer *layer;
+	Monitor *m;
+	struct wlr_layer_surface_v1_state old_state;
+
+	if (!layer_surface->output) {
+		layer_surface->output = selmon->wlr_output;
+	}
+
+	layer = calloc(1, sizeof(Layer));
+	if (!layer)
+		return;
+
+	layer->surface_commit.notify = commitlayernotify;
+	wl_signal_add(&layer_surface->surface->events.commit,
+		&layer->surface_commit);
+
+	layer->destroy.notify = destroylayernotify;
+	wl_signal_add(&layer_surface->events.destroy, &layer->destroy);
+	layer->map.notify = maplayernotify;
+	wl_signal_add(&layer_surface->events.map, &layer->map);
+	layer->unmap.notify = unmaplayernotify;
+	wl_signal_add(&layer_surface->events.unmap, &layer->unmap);
+
+	layer->layer_surface = layer_surface;
+	layer_surface->data = layer;
+
+	m = layer_surface->output->data;
+
+	wl_list_insert(&m->layers[layer_surface->client_pending.layer], &layer->link);
+
+	// Temporarily set the layer's current state to client_pending
+	// so that we can easily arrange it
+	old_state = layer_surface->current;
+	layer_surface->current = layer_surface->client_pending;
+	arrangelayers(m);
+	layer_surface->current = old_state;
+}
+
 void
 createpointer(struct wlr_input_device *device)
 {
@@ -636,6 +946,28 @@ cursorframe(struct wl_listener *listener, void *data)
 	wlr_seat_pointer_notify_frame(seat);
 }
 
+void
+destroylayernotify(struct wl_listener *listener, void *data)
+{
+	Layer *layer = wl_container_of(listener, layer, destroy);
+	Monitor *m;
+
+	if (layer->layer_surface->mapped)
+		unmaplayer(layer);
+	wl_list_remove(&layer->link);
+	wl_list_remove(&layer->destroy.link);
+	wl_list_remove(&layer->map.link);
+	wl_list_remove(&layer->unmap.link);
+	wl_list_remove(&layer->surface_commit.link);
+	if (layer->layer_surface->output) {
+		m = layer->layer_surface->output->data;
+		if (m)
+			arrangelayers(m);
+		layer->layer_surface->output = NULL;
+	}
+	free(layer);
+}
+
 void
 destroynotify(struct wl_listener *listener, void *data)
 {
@@ -901,6 +1233,14 @@ killclient(const Arg *arg)
 		wlr_xdg_toplevel_send_close(sel->surface.xdg);
 }
 
+void
+maplayernotify(struct wl_listener *listener, void *data)
+{
+	Layer *layer = wl_container_of(listener, layer, map);
+	wlr_surface_send_enter(layer->layer_surface->surface, layer->layer_surface->output);
+	// XXX recheck pointer focus
+}
+
 void
 maprequest(struct wl_listener *listener, void *data)
 {
@@ -1521,6 +1861,10 @@ setup(void)
 	wl_list_init(&fstack);
 	wl_list_init(&stack);
 	wl_list_init(&independents);
+
+	layer_shell = wlr_layer_shell_v1_create(dpy);
+	wl_signal_add(&layer_shell->events.new_surface, &new_layer_shell_surface);
+
 	xdg_shell = wlr_xdg_shell_create(dpy);
 	wl_signal_add(&xdg_shell->events.new_surface, &new_xdg_surface);
 
@@ -1703,6 +2047,20 @@ toggleview(const Arg *arg)
 	}
 }
 
+void
+unmaplayer(Layer *layer)
+{
+	if (
+		seat->keyboard_state.focused_surface
+		&& wlr_surface_is_layer_surface(seat->keyboard_state.focused_surface)
+		&& !wlr_layer_surface_v1_from_wlr_surface(seat->keyboard_state.focused_surface)
+			->current.keyboard_interactive
+	)
+		wlr_seat_keyboard_notify_clear_focus(seat);
+
+	// XXX recheck pointer focus
+}
+
 void
 unmapnotify(struct wl_listener *listener, void *data)
 {
@@ -1718,6 +2076,13 @@ unmapnotify(struct wl_listener *listener, void *data)
 	wl_list_remove(&c->slink);
 }
 
+void
+unmaplayernotify(struct wl_listener *listener, void *data)
+{
+	Layer *layer = wl_container_of(listener, layer, unmap);
+	unmaplayer(layer);
+}
+
 void
 view(const Arg *arg)
 {

protocols/wlr-layer-shell-unstable-v1.xml

@@ -0,0 +1,311 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="wlr_layer_shell_unstable_v1">
+  <copyright>
+    Copyright © 2017 Drew DeVault
+
+    Permission to use, copy, modify, distribute, and sell this
+    software and its documentation for any purpose is hereby granted
+    without fee, provided that the above copyright notice appear in
+    all copies and that both that copyright notice and this permission
+    notice appear in supporting documentation, and that the name of
+    the copyright holders not be used in advertising or publicity
+    pertaining to distribution of the software without specific,
+    written prior permission.  The copyright holders make no
+    representations about the suitability of this software for any
+    purpose.  It is provided "as is" without express or implied
+    warranty.
+
+    THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
+    SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+    FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
+    SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
+    AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+    ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
+    THIS SOFTWARE.
+  </copyright>
+
+  <interface name="zwlr_layer_shell_v1" version="3">
+    <description summary="create surfaces that are layers of the desktop">
+      Clients can use this interface to assign the surface_layer role to
+      wl_surfaces. Such surfaces are assigned to a "layer" of the output and
+      rendered with a defined z-depth respective to each other. They may also be
+      anchored to the edges and corners of a screen and specify input handling
+      semantics. This interface should be suitable for the implementation of
+      many desktop shell components, and a broad number of other applications
+      that interact with the desktop.
+    </description>
+
+    <request name="get_layer_surface">
+      <description summary="create a layer_surface from a surface">
+        Create a layer surface for an existing surface. This assigns the role of
+        layer_surface, or raises a protocol error if another role is already
+        assigned.
+
+        Creating a layer surface from a wl_surface which has a buffer attached
+        or committed is a client error, and any attempts by a client to attach
+        or manipulate a buffer prior to the first layer_surface.configure call
+        must also be treated as errors.
+
+        You may pass NULL for output to allow the compositor to decide which
+        output to use. Generally this will be the one that the user most
+        recently interacted with.
+
+        Clients can specify a namespace that defines the purpose of the layer
+        surface.
+      </description>
+      <arg name="id" type="new_id" interface="zwlr_layer_surface_v1"/>
+      <arg name="surface" type="object" interface="wl_surface"/>
+      <arg name="output" type="object" interface="wl_output" allow-null="true"/>
+      <arg name="layer" type="uint" enum="layer" summary="layer to add this surface to"/>
+      <arg name="namespace" type="string" summary="namespace for the layer surface"/>
+    </request>
+
+    <enum name="error">
+      <entry name="role" value="0" summary="wl_surface has another role"/>
+      <entry name="invalid_layer" value="1" summary="layer value is invalid"/>
+      <entry name="already_constructed" value="2" summary="wl_surface has a buffer attached or committed"/>
+    </enum>
+
+    <enum name="layer">
+      <description summary="available layers for surfaces">
+        These values indicate which layers a surface can be rendered in. They
+        are ordered by z depth, bottom-most first. Traditional shell surfaces
+        will typically be rendered between the bottom and top layers.
+        Fullscreen shell surfaces are typically rendered at the top layer.
+        Multiple surfaces can share a single layer, and ordering within a
+        single layer is undefined.
+      </description>
+
+      <entry name="background" value="0"/>
+      <entry name="bottom" value="1"/>
+      <entry name="top" value="2"/>
+      <entry name="overlay" value="3"/>
+    </enum>
+
+    <!-- Version 3 additions -->
+
+    <request name="destroy" type="destructor" since="3">
+      <description summary="destroy the layer_shell object">
+        This request indicates that the client will not use the layer_shell
+        object any more. Objects that have been created through this instance
+        are not affected.
+      </description>
+    </request>
+  </interface>
+
+  <interface name="zwlr_layer_surface_v1" version="3">
+    <description summary="layer metadata interface">
+      An interface that may be implemented by a wl_surface, for surfaces that
+      are designed to be rendered as a layer of a stacked desktop-like
+      environment.
+
+      Layer surface state (layer, size, anchor, exclusive zone,
+      margin, interactivity) is double-buffered, and will be applied at the
+      time wl_surface.commit of the corresponding wl_surface is called.
+    </description>
+
+    <request name="set_size">
+      <description summary="sets the size of the surface">
+        Sets the size of the surface in surface-local coordinates. The
+        compositor will display the surface centered with respect to its
+        anchors.
+
+        If you pass 0 for either value, the compositor will assign it and
+        inform you of the assignment in the configure event. You must set your
+        anchor to opposite edges in the dimensions you omit; not doing so is a
+        protocol error. Both values are 0 by default.
+
+        Size is double-buffered, see wl_surface.commit.
+      </description>
+      <arg name="width" type="uint"/>
+      <arg name="height" type="uint"/>
+    </request>
+
+    <request name="set_anchor">
+      <description summary="configures the anchor point of the surface">
+        Requests that the compositor anchor the surface to the specified edges
+        and corners. If two orthogonal edges are specified (e.g. 'top' and
+        'left'), then the anchor point will be the intersection of the edges
+        (e.g. the top left corner of the output); otherwise the anchor point
+        will be centered on that edge, or in the center if none is specified.
+
+        Anchor is double-buffered, see wl_surface.commit.
+      </description>
+      <arg name="anchor" type="uint" enum="anchor"/>
+    </request>
+
+    <request name="set_exclusive_zone">
+      <description summary="configures the exclusive geometry of this surface">
+        Requests that the compositor avoids occluding an area with other
+        surfaces. The compositor's use of this information is
+        implementation-dependent - do not assume that this region will not
+        actually be occluded.
+
+        A positive value is only meaningful if the surface is anchored to one
+        edge or an edge and both perpendicular edges. If the surface is not
+        anchored, anchored to only two perpendicular edges (a corner), anchored
+        to only two parallel edges or anchored to all edges, a positive value
+        will be treated the same as zero.
+
+        A positive zone is the distance from the edge in surface-local
+        coordinates to consider exclusive.
+
+        Surfaces that do not wish to have an exclusive zone may instead specify
+        how they should interact with surfaces that do. If set to zero, the
+        surface indicates that it would like to be moved to avoid occluding
+        surfaces with a positive exclusive zone. If set to -1, the surface
+        indicates that it would not like to be moved to accommodate for other
+        surfaces, and the compositor should extend it all the way to the edges
+        it is anchored to.
+
+        For example, a panel might set its exclusive zone to 10, so that
+        maximized shell surfaces are not shown on top of it. A notification
+        might set its exclusive zone to 0, so that it is moved to avoid
+        occluding the panel, but shell surfaces are shown underneath it. A
+        wallpaper or lock screen might set their exclusive zone to -1, so that
+        they stretch below or over the panel.
+
+        The default value is 0.
+
+        Exclusive zone is double-buffered, see wl_surface.commit.
+      </description>
+      <arg name="zone" type="int"/>
+    </request>
+
+    <request name="set_margin">
+      <description summary="sets a margin from the anchor point">
+        Requests that the surface be placed some distance away from the anchor
+        point on the output, in surface-local coordinates. Setting this value
+        for edges you are not anchored to has no effect.
+
+        The exclusive zone includes the margin.
+
+        Margin is double-buffered, see wl_surface.commit.
+      </description>
+      <arg name="top" type="int"/>
+      <arg name="right" type="int"/>
+      <arg name="bottom" type="int"/>
+      <arg name="left" type="int"/>
+    </request>
+
+    <request name="set_keyboard_interactivity">
+      <description summary="requests keyboard events">
+        Set to 1 to request that the seat send keyboard events to this layer
+        surface. For layers below the shell surface layer, the seat will use
+        normal focus semantics. For layers above the shell surface layers, the
+        seat will always give exclusive keyboard focus to the top-most layer
+        which has keyboard interactivity set to true.
+
+        Layer surfaces receive pointer, touch, and tablet events normally. If
+        you do not want to receive them, set the input region on your surface
+        to an empty region.
+
+        Events is double-buffered, see wl_surface.commit.
+      </description>
+      <arg name="keyboard_interactivity" type="uint"/>
+    </request>
+
+    <request name="get_popup">
+      <description summary="assign this layer_surface as an xdg_popup parent">
+        This assigns an xdg_popup's parent to this layer_surface.  This popup
+        should have been created via xdg_surface::get_popup with the parent set
+        to NULL, and this request must be invoked before committing the popup's
+        initial state.
+
+        See the documentation of xdg_popup for more details about what an
+        xdg_popup is and how it is used.
+      </description>
+      <arg name="popup" type="object" interface="xdg_popup"/>
+    </request>
+
+    <request name="ack_configure">
+      <description summary="ack a configure event">
+        When a configure event is received, if a client commits the
+        surface in response to the configure event, then the client
+        must make an ack_configure request sometime before the commit
+        request, passing along the serial of the configure event.
+
+        If the client receives multiple configure events before it
+        can respond to one, it only has to ack the last configure event.
+
+        A client is not required to commit immediately after sending
+        an ack_configure request - it may even ack_configure several times
+        before its next surface commit.
+
+        A client may send multiple ack_configure requests before committing, but
+        only the last request sent before a commit indicates which configure
+        event the client really is responding to.
+      </description>
+      <arg name="serial" type="uint" summary="the serial from the configure event"/>
+    </request>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the layer_surface">
+        This request destroys the layer surface.
+      </description>
+    </request>
+
+    <event name="configure">
+      <description summary="suggest a surface change">
+        The configure event asks the client to resize its surface.
+
+        Clients should arrange their surface for the new states, and then send
+        an ack_configure request with the serial sent in this configure event at
+        some point before committing the new surface.
+
+        The client is free to dismiss all but the last configure event it
+        received.
+
+        The width and height arguments specify the size of the window in
+        surface-local coordinates.
+
+        The size is a hint, in the sense that the client is free to ignore it if
+        it doesn't resize, pick a smaller size (to satisfy aspect ratio or
+        resize in steps of NxM pixels). If the client picks a smaller size and
+        is anchored to two opposite anchors (e.g. 'top' and 'bottom'), the
+        surface will be centered on this axis.
+
+        If the width or height arguments are zero, it means the client should
+        decide its own window dimension.
+      </description>
+      <arg name="serial" type="uint"/>
+      <arg name="width" type="uint"/>
+      <arg name="height" type="uint"/>
+    </event>
+
+    <event name="closed">
+      <description summary="surface should be closed">
+        The closed event is sent by the compositor when the surface will no
+        longer be shown. The output may have been destroyed or the user may
+        have asked for it to be removed. Further changes to the surface will be
+        ignored. The client should destroy the resource after receiving this
+        event, and create a new surface if they so choose.
+      </description>
+    </event>
+
+    <enum name="error">
+      <entry name="invalid_surface_state" value="0" summary="provided surface state is invalid"/>
+      <entry name="invalid_size" value="1" summary="size is invalid"/>
+      <entry name="invalid_anchor" value="2" summary="anchor bitfield is invalid"/>
+    </enum>
+
+    <enum name="anchor" bitfield="true">
+      <entry name="top" value="1" summary="the top edge of the anchor rectangle"/>
+      <entry name="bottom" value="2" summary="the bottom edge of the anchor rectangle"/>
+      <entry name="left" value="4" summary="the left edge of the anchor rectangle"/>
+      <entry name="right" value="8" summary="the right edge of the anchor rectangle"/>
+    </enum>
+
+    <!-- Version 2 additions -->
+
+    <request name="set_layer" since="2">
+      <description summary="change the layer of the surface">
+        Change the layer that the surface is rendered on.
+
+        Layer is double-buffered, see wl_surface.commit.
+      </description>
+      <arg name="layer" type="uint" enum="zwlr_layer_shell_v1.layer" summary="layer to move this surface to"/>
+    </request>
+  </interface>
+</protocol>