Merge pull request #1642 from swaywm/layer-shell

Implement layer shell (rendering)

14 files changed, 525 insertions, 57 deletions

diff --git a/include/sway/layers.h b/include/sway/layers.h
new file mode 100644
index 00000000..22054be1
--- /dev/null
+++ b/include/sway/layers.h
@@ -0,0 +1,27 @@
+#ifndef _SWAY_LAYERS_H
+#define _SWAY_LAYERS_H
+#include <stdbool.h>
+#include <wlr/types/wlr_box.h>
+#include <wlr/types/wlr_surface.h>
+#include <wlr/types/wlr_layer_shell.h>
+
+struct sway_layer_surface {
+        struct wlr_layer_surface *layer_surface;
+        struct wl_list link;
+
+        struct wl_listener destroy;
+        struct wl_listener map;
+        struct wl_listener unmap;
+        struct wl_listener surface_commit;
+        struct wl_listener output_destroy;
+        struct wl_listener output_mode;
+        struct wl_listener output_transform;
+
+        bool configured;
+        struct wlr_box geo;
+};
+
+struct sway_output;
+void arrange_layers(struct sway_output *output);
+
+#endif
diff --git a/include/sway/output.h b/include/sway/output.h
index 95d64705..f899230f 100644
--- a/include/sway/output.h
+++ b/include/sway/output.h
@@ -1,7 +1,9 @@
 #ifndef _SWAY_OUTPUT_H
 #define _SWAY_OUTPUT_H
 #include <time.h>
+#include <unistd.h>
 #include <wayland-server.h>
+#include <wlr/types/wlr_box.h>
 #include <wlr/types/wlr_output.h>
 
 struct sway_server;
@@ -13,8 +15,14 @@ struct sway_output {
         struct sway_server *server;
         struct timespec last_frame;
 
+        struct wl_list layers[4]; // sway_layer_surface::link
+        struct wlr_box usable_area;
+
         struct wl_listener frame;
-        struct wl_listener output_destroy;
+        struct wl_listener destroy;
+        struct wl_listener mode;
+
+        pid_t bg_pid;
 };
 
 #endif
diff --git a/include/sway/server.h b/include/sway/server.h
index eb7fa2ff..25eb64fe 100644
--- a/include/sway/server.h
+++ b/include/sway/server.h
@@ -6,6 +6,7 @@
 #include <wlr/backend/session.h>
 #include <wlr/types/wlr_compositor.h>
 #include <wlr/types/wlr_data_device.h>
+#include <wlr/types/wlr_layer_shell.h>
 #include <wlr/types/wlr_xdg_shell_v6.h>
 #include <wlr/render/wlr_renderer.h>
 // TODO WLR: make Xwayland optional
@@ -27,6 +28,9 @@ struct sway_server {
         struct wl_listener new_output;
         struct wl_listener output_frame;
 
+        struct wlr_layer_shell *layer_shell;
+        struct wl_listener layer_shell_surface;
+
         struct wlr_xdg_shell_v6 *xdg_shell_v6;
         struct wl_listener xdg_shell_v6_surface;
 
@@ -46,6 +50,7 @@ void server_run(struct sway_server *server);
 
 void handle_new_output(struct wl_listener *listener, void *data);
 
+void handle_layer_shell_surface(struct wl_listener *listener, void *data);
 void handle_xdg_shell_v6_surface(struct wl_listener *listener, void *data);
 void handle_xwayland_surface(struct wl_listener *listener, void *data);
 void handle_wl_shell_surface(struct wl_listener *listener, void *data);
diff --git a/protocols/meson.build b/protocols/meson.build
index 1fda600e..3f79e719 100644
--- a/protocols/meson.build
+++ b/protocols/meson.build
@@ -14,24 +14,57 @@ wayland_scanner_client = generator(
         arguments: ['client-header', '@INPUT@', '@OUTPUT@'],
 )
 
-protocols = [
+wayland_scanner_server = generator(
+        wayland_scanner,
+        output: '@BASENAME@-protocol.h',
+        arguments: ['server-header', '@INPUT@', '@OUTPUT@'],
+)
+
+client_protocols = [
         [wl_protocol_dir, 'stable/xdg-shell/xdg-shell.xml'],
         ['wlr-layer-shell-unstable-v1.xml']
 ]
 
-wl_protos_src = []
-wl_protos_headers = []
+server_protocols = [
+        ['wlr-layer-shell-unstable-v1.xml']
+]
+
+client_protos_src = []
+client_protos_headers = []
+
+server_protos_src = []
+server_protos_headers = []
 
-foreach p : protocols
+foreach p : client_protocols
         xml = join_paths(p)
-        wl_protos_src += wayland_scanner_code.process(xml)
-        wl_protos_headers += wayland_scanner_client.process(xml)
+        client_protos_src += wayland_scanner_code.process(xml)
+        client_protos_headers += wayland_scanner_client.process(xml)
 endforeach
 
-lib_wl_protos = static_library('wl_protos', wl_protos_src + wl_protos_headers,
-        dependencies: [wayland_client]) # for the include directory
+foreach p : server_protocols
+        xml = join_paths(p)
+        server_protos_src += wayland_scanner_code.process(xml)
+        server_protos_headers += wayland_scanner_server.process(xml)
+endforeach
+
+lib_client_protos = static_library(
+        'client_protos',
+        client_protos_src + client_protos_headers,
+        dependencies: [wayland_client]
+) # for the include directory
+
+client_protos = declare_dependency(
+        link_with: lib_client_protos,
+        sources: client_protos_headers,
+)
+
+lib_server_protos = static_library(
+        'server_protos',
+        server_protos_src + server_protos_headers,
+        dependencies: [wayland_client]
+) # for the include directory
 
-sway_protos = declare_dependency(
-        link_with: lib_wl_protos,
-        sources: wl_protos_headers,
+server_protos = declare_dependency(
+        link_with: lib_server_protos,
+        sources: server_protos_headers,
 )
diff --git a/sway/commands/output.c b/sway/commands/output.c
index e747eb4e..35bc8099 100644
--- a/sway/commands/output.c
+++ b/sway/commands/output.c
@@ -188,7 +188,7 @@ static struct cmd_results *cmd_output_background(struct output_config *output,
                 }
 
                 wordexp_t p;
-                char *src = join_args(argv + *i - 1, j);
+                char *src = join_args(argv + *i, j);
                 if (wordexp(src, &p, 0) != 0 || p.we_wordv[0] == NULL) {
                         return cmd_results_new(CMD_INVALID, "output",
                                 "Invalid syntax (%s).", src);
diff --git a/sway/config/output.c b/sway/config/output.c
index 69e883f1..9e211861 100644
--- a/sway/config/output.c
+++ b/sway/config/output.c
@@ -1,7 +1,10 @@
 #define _XOPEN_SOURCE 700
+#include <assert.h>
 #include <stdbool.h>
 #include <string.h>
-#include <assert.h>
+#include <signal.h>
+#include <sys/wait.h>
+#include <unistd.h>
 #include <wlr/types/wlr_output.h>
 #include <wlr/types/wlr_output_layout.h>
 #include "sway/config.h"
@@ -107,6 +110,16 @@ static void set_mode(struct wlr_output *output, int width, int height,
         }
 }
 
+void terminate_swaybg(pid_t pid) {
+        int ret = kill(pid, SIGTERM);
+        if (ret != 0) {
+                wlr_log(L_ERROR, "Unable to terminate swaybg [pid: %d]", pid);
+        } else {
+                int status;
+                waitpid(pid, &status, 0);
+        }
+}
+
 void apply_output_config(struct output_config *oc, swayc_t *output) {
         assert(output->type == C_OUTPUT);
 
@@ -160,12 +173,12 @@ void apply_output_config(struct output_config *oc, swayc_t *output) {
         }
 
         if (oc && oc->background) {
-                // TODO swaybg
-                /*if (output->bg_pid != 0) {
-                        terminate_swaybg(output->bg_pid);
+                if (output->sway_output->bg_pid != 0) {
+                        terminate_swaybg(output->sway_output->bg_pid);
                 }
 
-                wlr_log(L_DEBUG, "Setting background for output %d to %s", output_i, oc->background);
+                wlr_log(L_DEBUG, "Setting background for output %d to %s",
+                                output_i, oc->background);
 
                 size_t bufsize = 12;
                 char output_id[bufsize];
@@ -173,17 +186,17 @@ void apply_output_config(struct output_config *oc, swayc_t *output) {
                 output_id[bufsize-1] = 0;
 
                 char *const cmd[] = {
-                        "swaybg",
+                        "./swaybg/swaybg",
                         output_id,
                         oc->background,
                         oc->background_option,
                         NULL,
                 };
 
-                output->bg_pid = fork();
-                if (output->bg_pid == 0) {
+                output->sway_output->bg_pid = fork();
+                if (output->sway_output->bg_pid == 0) {
                         execvp(cmd[0], cmd);
-                }*/
+                }
         }
 }
 
diff --git a/sway/desktop/layer_shell.c b/sway/desktop/layer_shell.c
new file mode 100644
index 00000000..bd62f84a
--- /dev/null
+++ b/sway/desktop/layer_shell.c
@@ -0,0 +1,320 @@
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wayland-server.h>
+#include <wlr/types/wlr_box.h>
+#include <wlr/types/wlr_layer_shell.h>
+#include <wlr/types/wlr_output.h>
+#include <wlr/util/log.h>
+#include "sway/layers.h"
+#include "sway/layout.h"
+#include "sway/output.h"
+#include "sway/server.h"
+
+static void apply_exclusive(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) {
+        if (exclusive <= 0) {
+                return;
+        }
+        struct {
+                uint32_t anchors;
+                int *positive_axis;
+                int *negative_axis;
+                int margin;
+        } edges[] = {
+                {
+                        .anchors =
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT |
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP,
+                        .positive_axis = &usable_area->y,
+                        .negative_axis = &usable_area->height,
+                        .margin = margin_top,
+                },
+                {
+                        .anchors =
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT |
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM,
+                        .positive_axis = NULL,
+                        .negative_axis = &usable_area->height,
+                        .margin = margin_bottom,
+                },
+                {
+                        .anchors =
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT |
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP |
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM,
+                        .positive_axis = &usable_area->x,
+                        .negative_axis = &usable_area->width,
+                        .margin = margin_left,
+                },
+                {
+                        .anchors =
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP |
+                                ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM,
+                        .positive_axis = NULL,
+                        .negative_axis = &usable_area->width,
+                        .margin = margin_right,
+                },
+        };
+        for (size_t i = 0; i < sizeof(edges) / sizeof(edges[0]); ++i) {
+                if ((anchor & edges[i].anchors) == edges[i].anchors) {
+                        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;
+                        }
+                }
+        }
+}
+
+static void arrange_layer(struct sway_output *output, struct wl_list *list,
+                struct wlr_box *usable_area, bool exclusive) {
+        struct sway_layer_surface *sway_layer;
+        struct wlr_box full_area = { 0 };
+        wlr_output_effective_resolution(output->wlr_output,
+                        &full_area.width, &full_area.height);
+        wl_list_for_each(sway_layer, list, link) {
+                struct wlr_layer_surface *layer = sway_layer->layer_surface;
+                struct wlr_layer_surface_state *state = &layer->current;
+                if (exclusive != (state->exclusive_zone > 0)) {
+                        continue;
+                }
+                struct wlr_box bounds;
+                if (state->exclusive_zone == -1) {
+                        bounds = full_area;
+                } else {
+                        bounds = *usable_area;
+                }
+                struct wlr_box box = {
+                        .width = state->desired_width,
+                        .height = state->desired_height
+                };
+                // Horizontal axis
+                const uint32_t both_horiz = ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT
+                        | ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT;
+                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
+                const uint32_t both_vert = ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP
+                        | ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM;
+                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) {
+                        // TODO: Bubble up a protocol error?
+                        wlr_layer_surface_close(layer);
+                        continue;
+                }
+                // Apply
+                sway_layer->geo = box;
+                apply_exclusive(usable_area, state->anchor, state->exclusive_zone,
+                                state->margin.top, state->margin.right,
+                                state->margin.bottom, state->margin.left);
+                wlr_layer_surface_configure(layer, box.width, box.height);
+        }
+}
+
+void arrange_layers(struct sway_output *output) {
+        struct wlr_box usable_area = { 0 };
+        wlr_output_effective_resolution(output->wlr_output,
+                        &usable_area.width, &usable_area.height);
+        struct wlr_box usable_area_before = output->usable_area;
+
+        // Arrange exclusive surfaces from top->bottom
+        arrange_layer(output, &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY],
+                        &usable_area, true);
+        arrange_layer(output, &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP],
+                        &usable_area, true);
+        arrange_layer(output, &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM],
+                        &usable_area, true);
+        arrange_layer(output, &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND],
+                        &usable_area, true);
+        memcpy(&output->usable_area, &usable_area, sizeof(struct wlr_box));
+
+        if (memcmp(&usable_area_before,
+                        &usable_area, sizeof(struct wlr_box)) != 0) {
+                wlr_log(L_DEBUG, "arrange");
+                arrange_windows(output->swayc, -1, -1);
+        }
+
+        // Arrange non-exlusive surfaces from top->bottom
+        usable_area.x = usable_area.y = 0;
+        wlr_output_effective_resolution(output->wlr_output,
+                        &usable_area.width, &usable_area.height);
+        arrange_layer(output, &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY],
+                        &usable_area, false);
+        arrange_layer(output, &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP],
+                        &usable_area, false);
+        arrange_layer(output, &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM],
+                        &usable_area, false);
+        arrange_layer(output, &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND],
+                        &usable_area, false);
+}
+
+static void handle_output_destroy(struct wl_listener *listener, void *data) {
+        struct sway_layer_surface *sway_layer =
+                wl_container_of(listener, sway_layer, output_destroy);
+        wl_list_remove(&sway_layer->output_destroy.link);
+        wl_list_remove(&sway_layer->output_mode.link);
+        wl_list_remove(&sway_layer->output_transform.link);
+        sway_layer->layer_surface->output = NULL;
+        wlr_layer_surface_close(sway_layer->layer_surface);
+}
+
+static void handle_output_mode(struct wl_listener *listener, void *data) {
+        struct wlr_output *output = data;
+        arrange_layers((struct sway_output *)output->data);
+}
+
+static void handle_output_transform(struct wl_listener *listener, void *data) {
+        struct wlr_output *output = data;
+        arrange_layers((struct sway_output *)output->data);
+}
+
+static void handle_surface_commit(struct wl_listener *listener, void *data) {
+        struct sway_layer_surface *layer =
+                wl_container_of(listener, layer, surface_commit);
+        struct wlr_layer_surface *layer_surface = layer->layer_surface;
+        struct wlr_output *wlr_output = layer_surface->output;
+        if (wlr_output != NULL) {
+                struct sway_output *output = wlr_output->data;
+                struct wlr_box old_geo = layer->geo;
+                arrange_layers(output);
+                if (memcmp(&old_geo, &layer->geo, sizeof(struct wlr_box)) != 0) {
+                        // TODO DAMAGE apply whole surface from previous and new geos
+                } else {
+                        // TODO DAMAGE from surface damage
+                }
+        }
+}
+
+static void unmap(struct wlr_layer_surface *layer_surface) {
+        // TODO DAMAGE
+}
+
+static void handle_destroy(struct wl_listener *listener, void *data) {
+        struct sway_layer_surface *sway_layer = wl_container_of(
+                        listener, sway_layer, destroy);
+        if (sway_layer->layer_surface->mapped) {
+                unmap(sway_layer->layer_surface);
+        }
+        wl_list_remove(&sway_layer->link);
+        wl_list_remove(&sway_layer->destroy.link);
+        wl_list_remove(&sway_layer->map.link);
+        wl_list_remove(&sway_layer->unmap.link);
+        wl_list_remove(&sway_layer->surface_commit.link);
+        if (sway_layer->layer_surface->output != NULL) {
+                wl_list_remove(&sway_layer->output_destroy.link);
+                wl_list_remove(&sway_layer->output_mode.link);
+                wl_list_remove(&sway_layer->output_transform.link);
+        }
+        struct sway_output *output = sway_layer->layer_surface->output->data;
+        arrange_layers(output);
+        free(sway_layer);
+}
+
+static void handle_map(struct wl_listener *listener, void *data) {
+        // TODO DAMAGE
+}
+
+static void handle_unmap(struct wl_listener *listener, void *data) {
+        struct sway_layer_surface *sway_layer = wl_container_of(
+                        listener, sway_layer, unmap);
+        unmap(sway_layer->layer_surface);
+}
+
+void handle_layer_shell_surface(struct wl_listener *listener, void *data) {
+        struct wlr_layer_surface *layer_surface = data;
+        struct sway_server *server =
+                wl_container_of(listener, server, layer_shell_surface);
+        wlr_log(L_DEBUG, "new layer surface: namespace %s layer %d anchor %d "
+                        "size %dx%d margin %d,%d,%d,%d",
+                layer_surface->namespace, layer_surface->layer, layer_surface->layer,
+                layer_surface->client_pending.desired_width,
+                layer_surface->client_pending.desired_height,
+                layer_surface->client_pending.margin.top,
+                layer_surface->client_pending.margin.right,
+                layer_surface->client_pending.margin.bottom,
+                layer_surface->client_pending.margin.left);
+
+        struct sway_layer_surface *sway_layer =
+                calloc(1, sizeof(struct sway_layer_surface));
+        if (!sway_layer) {
+                return;
+        }
+
+        sway_layer->surface_commit.notify = handle_surface_commit;
+        wl_signal_add(&layer_surface->surface->events.commit,
+                &sway_layer->surface_commit);
+
+        sway_layer->output_destroy.notify = handle_output_destroy;
+        wl_signal_add(&layer_surface->output->events.destroy,
+                &sway_layer->output_destroy);
+
+        sway_layer->output_mode.notify = handle_output_mode;
+        wl_signal_add(&layer_surface->output->events.mode,
+                &sway_layer->output_mode);
+
+        sway_layer->output_transform.notify = handle_output_transform;
+        wl_signal_add(&layer_surface->output->events.transform,
+                &sway_layer->output_transform);
+
+        sway_layer->destroy.notify = handle_destroy;
+        wl_signal_add(&layer_surface->events.destroy, &sway_layer->destroy);
+        sway_layer->map.notify = handle_map;
+        wl_signal_add(&layer_surface->events.map, &sway_layer->map);
+        sway_layer->unmap.notify = handle_unmap;
+        wl_signal_add(&layer_surface->events.unmap, &sway_layer->unmap);
+        // TODO: Listen for subsurfaces
+
+        sway_layer->layer_surface = layer_surface;
+        layer_surface->data = sway_layer;
+
+        struct sway_output *output = layer_surface->output->data;
+        wl_list_insert(&output->layers[layer_surface->layer], &sway_layer->link);
+
+        // Temporarily set the layer's current state to client_pending
+        // So that we can easily arrange it
+        struct wlr_layer_surface_state old_state = layer_surface->current;
+        layer_surface->current = layer_surface->client_pending;
+        arrange_layers(output);
+        layer_surface->current = old_state;
+}
diff --git a/sway/desktop/output.c b/sway/desktop/output.c
index 6c990c47..9e7fbcc6 100644
--- a/sway/desktop/output.c
+++ b/sway/desktop/output.c
@@ -4,14 +4,17 @@
 #include <time.h>
 #include <wayland-server.h>
 #include <wlr/render/wlr_renderer.h>
+#include <wlr/types/wlr_box.h>
 #include <wlr/types/wlr_matrix.h>
 #include <wlr/types/wlr_output.h>
+#include <wlr/types/wlr_output_layout.h>
 #include <wlr/types/wlr_surface.h>
 #include <wlr/types/wlr_wl_shell.h>
 #include "log.h"
 #include "sway/container.h"
 #include "sway/input/input-manager.h"
 #include "sway/input/seat.h"
+#include "sway/layers.h"
 #include "sway/layout.h"
 #include "sway/output.h"
 #include "sway/server.h"
@@ -78,9 +81,7 @@ static void render_surface(struct wlr_surface *surface,
                 rotate_child_position(&sx, &sy, sw, sh, width, height, rotation);
 
                 render_surface(subsurface->surface, wlr_output, when,
-                        lx + sx,
-                        ly + sy,
-                        rotation);
+                        lx + sx, ly + sy, rotation);
         }
 }
 
@@ -139,9 +140,15 @@ static void render_wl_shell_surface(struct wlr_wl_shell_surface *surface,
         }
 }
 
+struct render_data {
+        struct sway_output *output;
+        struct timespec *now;
+};
 
 static void output_frame_view(swayc_t *view, void *data) {
-        struct sway_output *output = data;
+        struct render_data *rdata = data;
+        struct sway_output *output = rdata->output;
+        struct timespec *now = rdata->now;
         struct wlr_output *wlr_output = output->wlr_output;
         struct sway_view *sway_view = view->sway_view;
         struct wlr_surface *surface = sway_view->surface;
@@ -154,29 +161,38 @@ static void output_frame_view(swayc_t *view, void *data) {
         case SWAY_XDG_SHELL_V6_VIEW: {
                 int window_offset_x = view->sway_view->wlr_xdg_surface_v6->geometry.x;
                 int window_offset_y = view->sway_view->wlr_xdg_surface_v6->geometry.y;
-                render_surface(surface, wlr_output, &output->last_frame,
-                        view->x - window_offset_x,
-                        view->y - window_offset_y,
-                        0);
+                render_surface(surface, wlr_output, now,
+                        view->x - window_offset_x, view->y - window_offset_y, 0);
                 render_xdg_v6_popups(sway_view->wlr_xdg_surface_v6, wlr_output,
-                        &output->last_frame,
-                        view->x - window_offset_x, view->y - window_offset_y,
-                        0);
+                        now, view->x - window_offset_x, view->y - window_offset_y, 0);
                 break;
         }
         case SWAY_WL_SHELL_VIEW:
                 render_wl_shell_surface(sway_view->wlr_wl_shell_surface, wlr_output,
-                        &output->last_frame, view->x, view->y, 0, false);
+                        now, view->x, view->y, 0, false);
                 break;
         case SWAY_XWAYLAND_VIEW:
-                render_surface(surface, wlr_output, &output->last_frame, view->x,
-                        view->y, 0);
+                render_surface(surface, wlr_output, now, view->x, view->y, 0);
                 break;
         default:
                 break;
         }
 }
 
+static void render_layer(struct sway_output *output,
+                const struct wlr_box *output_layout_box,
+                struct timespec *when,
+                struct wl_list *layer) {
+        struct sway_layer_surface *sway_layer;
+        wl_list_for_each(sway_layer, layer, link) {
+                struct wlr_layer_surface *layer = sway_layer->layer_surface;
+                render_surface(layer->surface, output->wlr_output, when,
+                                sway_layer->geo.x + output_layout_box->x,
+                                sway_layer->geo.y + output_layout_box->y, 0);
+                wlr_surface_send_frame_done(layer->surface, when);
+        }
+}
+
 static void output_frame_notify(struct wl_listener *listener, void *data) {
         struct sway_output *soutput = wl_container_of(listener, soutput, frame);
         struct wlr_output *wlr_output = data;
@@ -189,13 +205,29 @@ static void output_frame_notify(struct wl_listener *listener, void *data) {
         wlr_output_make_current(wlr_output, &buffer_age);
         wlr_renderer_begin(server->renderer, wlr_output->width, wlr_output->height);
 
+        struct timespec now;
+        clock_gettime(CLOCK_MONOTONIC, &now);
+
+        struct wlr_output_layout *layout = root_container.sway_root->output_layout;
+        const struct wlr_box *output_box = wlr_output_layout_get_box(
+                        layout, wlr_output);
+
+        render_layer(soutput, output_box, &now,
+                        &soutput->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND]);
+        render_layer(soutput, output_box, &now,
+                        &soutput->layers[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM]);
+
         struct sway_seat *seat = input_manager_current_seat(input_manager);
         swayc_t *focus = sway_seat_get_focus_inactive(seat, soutput->swayc);
         swayc_t *workspace = (focus->type == C_WORKSPACE ?
                         focus :
                         swayc_parent_by_type(focus, C_WORKSPACE));
 
-        swayc_descendants_of_type(workspace, C_VIEW, output_frame_view, soutput);
+        struct render_data rdata = {
+                .output = soutput,
+                .now = &now,
+        };
+        swayc_descendants_of_type(workspace, C_VIEW, output_frame_view, &rdata);
 
         // render unmanaged views on top
         struct sway_view *view;
@@ -210,22 +242,31 @@ static void output_frame_notify(struct wl_listener *listener, void *data) {
                 }
         }
 
-        wlr_renderer_end(server->renderer);
-        wlr_output_swap_buffers(wlr_output, &soutput->last_frame, NULL);
+        // TODO: Consider revising this when fullscreen windows are supported
+        render_layer(soutput, output_box, &now,
+                        &soutput->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP]);
+        render_layer(soutput, output_box, &now,
+                        &soutput->layers[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY]);
 
-        struct timespec now;
-        clock_gettime(CLOCK_MONOTONIC, &now);
+        wlr_renderer_end(server->renderer);
+        wlr_output_swap_buffers(wlr_output, &now, NULL);
         soutput->last_frame = now;
 }
 
 static void handle_output_destroy(struct wl_listener *listener, void *data) {
-        struct sway_output *output = wl_container_of(listener, output, output_destroy);
+        struct sway_output *output = wl_container_of(listener, output, destroy);
         struct wlr_output *wlr_output = data;
         wlr_log(L_DEBUG, "Output %p %s removed", wlr_output, wlr_output->name);
 
         destroy_output(output->swayc);
 }
 
+static void handle_output_mode(struct wl_listener *listener, void *data) {
+        struct sway_output *output = wl_container_of(listener, output, mode);
+        arrange_layers(output);
+        arrange_windows(output->swayc, -1, -1);
+}
+
 void handle_new_output(struct wl_listener *listener, void *data) {
         struct sway_server *server = wl_container_of(listener, server, new_output);
         struct wlr_output *wlr_output = data;
@@ -236,6 +277,7 @@ void handle_new_output(struct wl_listener *listener, void *data) {
                 return;
         }
         output->wlr_output = wlr_output;
+        wlr_output->data = output;
         output->server = server;
 
         if (!wl_list_empty(&wlr_output->modes)) {
@@ -250,13 +292,20 @@ void handle_new_output(struct wl_listener *listener, void *data) {
                 return;
         }
 
+        size_t len = sizeof(output->layers) / sizeof(output->layers[0]);
+        for (size_t i = 0; i < len; ++i) {
+                wl_list_init(&output->layers[i]);
+        }
+
         sway_input_manager_configure_xcursor(input_manager);
 
         wl_signal_add(&wlr_output->events.frame, &output->frame);
         output->frame.notify = output_frame_notify;
+        wl_signal_add(&wlr_output->events.destroy, &output->destroy);
+        output->destroy.notify = handle_output_destroy;
+        wl_signal_add(&wlr_output->events.mode, &output->mode);
+        output->mode.notify = handle_output_mode;
 
-        wl_signal_add(&wlr_output->events.destroy, &output->output_destroy);
-        output->output_destroy.notify = handle_output_destroy;
-
+        arrange_layers(output);
         arrange_windows(&root_container, -1, -1);
 }
diff --git a/sway/desktop/xwayland.c b/sway/desktop/xwayland.c
index 6b5e03f9..f9b5242b 100644
--- a/sway/desktop/xwayland.c
+++ b/sway/desktop/xwayland.c
@@ -84,7 +84,7 @@ static void set_activated(struct sway_view *view, bool activated) {
         wlr_xwayland_surface_activate(surface, activated);
 }
 
-static void close(struct sway_view *view) {
+static void close_view(struct sway_view *view) {
         if (!assert_xwayland(view)) {
                 return;
         }
@@ -203,7 +203,7 @@ void handle_xwayland_surface(struct wl_listener *listener, void *data) {
         sway_view->iface.set_size = set_size;
         sway_view->iface.set_position = set_position;
         sway_view->iface.set_activated = set_activated;
-        sway_view->iface.close = close;
+        sway_view->iface.close = close_view;
         sway_view->wlr_xwayland_surface = xsurface;
         sway_view->sway_xwayland_surface = sway_surface;
         sway_view->surface = xsurface->surface;
diff --git a/sway/meson.build b/sway/meson.build
index 26e56ad2..8bddb11b 100644
--- a/sway/meson.build
+++ b/sway/meson.build
@@ -46,6 +46,7 @@ sway_sources = files(
         'ipc-json.c',
         'ipc-server.c',
         'desktop/output.c',
+        'desktop/layer_shell.c',
         'desktop/wl_shell.c',
         'desktop/xdg_shell_v6.c',
         'desktop/xwayland.c',
@@ -57,14 +58,15 @@ sway_sources = files(
 )
 
 sway_deps = [
+        jsonc,
+        libcap,
+        libinput,
+        math,
         pcre,
         pixman,
+        server_protos,
         wayland_server,
-        jsonc,
         wlroots,
-        libcap,
-        math,
-        libinput,
         xkbcommon,
 ]
 
diff --git a/sway/server.c b/sway/server.c
index ca08d7fb..92f72f13 100644
--- a/sway/server.c
+++ b/sway/server.c
@@ -7,6 +7,7 @@
 #include <wlr/render/wlr_renderer.h>
 #include <wlr/render/gles2.h>
 #include <wlr/types/wlr_compositor.h>
+#include <wlr/types/wlr_layer_shell.h>
 #include <wlr/types/wlr_wl_shell.h>
 // TODO WLR: make Xwayland optional
 #include <wlr/xwayland.h>
@@ -51,6 +52,11 @@ bool server_init(struct sway_server *server) {
         server->new_output.notify = handle_new_output;
         wl_signal_add(&server->backend->events.new_output, &server->new_output);
 
+        server->layer_shell = wlr_layer_shell_create(server->wl_display);
+        wl_signal_add(&server->layer_shell->events.new_surface,
+                &server->layer_shell_surface);
+        server->layer_shell_surface.notify = handle_layer_shell_surface;
+
         server->xdg_shell_v6 = wlr_xdg_shell_v6_create(server->wl_display);
         wl_signal_add(&server->xdg_shell_v6->events.new_surface,
                 &server->xdg_shell_v6_surface);
diff --git a/sway/tree/container.c b/sway/tree/container.c
index 705221d7..bbafe9ec 100644
--- a/sway/tree/container.c
+++ b/sway/tree/container.c
@@ -254,7 +254,9 @@ swayc_t *destroy_output(swayc_t *output) {
                 }
         }
 
-        wl_list_remove(&output->sway_output->output_destroy.link);
+        wl_list_remove(&output->sway_output->frame.link);
+        wl_list_remove(&output->sway_output->destroy.link);
+        wl_list_remove(&output->sway_output->mode.link);
 
         wlr_log(L_DEBUG, "OUTPUT: Destroying output '%s'", output->name);
         free_swayc(output);
diff --git a/sway/tree/layout.c b/sway/tree/layout.c
index 3d04a1a7..de9e7b58 100644
--- a/sway/tree/layout.c
+++ b/sway/tree/layout.c
@@ -204,10 +204,13 @@ void arrange_windows(swayc_t *container, double width, double height) {
         case C_WORKSPACE:
                 {
                         swayc_t *output = swayc_parent_by_type(container, C_OUTPUT);
-                        container->width = output->width;
-                        container->height = output->height;
-                        container->x = x;
-                        container->y = y;
+                        struct wlr_box *area = &output->sway_output->usable_area;
+                        wlr_log(L_DEBUG, "Usable area for ws: %dx%d@%d,%d",
+                                        area->width, area->height, area->x, area->y);
+                        container->width = area->width;
+                        container->height = area->height;
+                        container->x = x = area->x;
+                        container->y = y = area->y;
                         wlr_log(L_DEBUG, "Arranging workspace '%s' at %f, %f",
                                         container->name, container->x, container->y);
                 }
diff --git a/swaybg/meson.build b/swaybg/meson.build
index 5e10f3c7..8704de6d 100644
--- a/swaybg/meson.build
+++ b/swaybg/meson.build
@@ -4,12 +4,12 @@ executable(
         include_directories: [sway_inc],
         dependencies: [
                 cairo,
+                client_protos,
                 gdk_pixbuf,
                 jsonc,
                 math,
                 pango,
                 pangocairo,
-                sway_protos,
                 wayland_client,
                 wlroots,
         ],