Merge pull request #887 from swaywm/layer-optional-output

Update layer shell with optional wl_output

examples/layer-shell.c

@@ -1,6 +1,7 @@
 #define _POSIX_C_SOURCE 199309L
 #include <assert.h>
 #include <GLES2/gl2.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -28,7 +29,7 @@ struct wl_egl_window *egl_window;
 struct wlr_egl_surface *egl_surface;
 struct wl_callback *frame_callback;
 
-static uint32_t output = 0;
+static uint32_t output = UINT32_MAX;
 static uint32_t layer = ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND;
 static uint32_t anchor = 0;
 static uint32_t width = 256, height = 256;
@@ -283,11 +284,13 @@ static void handle_global(void *data, struct wl_registry *registry,
 		shm = wl_registry_bind(registry, name,
 				&wl_shm_interface, 1);
 	} else if (strcmp(interface, "wl_output") == 0) {
-		if (output == 0 && !wl_output) {
-			wl_output = wl_registry_bind(registry, name,
-					&wl_output_interface, 1);
-		} else {
-			output--;
+		if (output != UINT32_MAX) {
+			if (!wl_output) {
+				wl_output = wl_registry_bind(registry, name,
+						&wl_output_interface, 1);
+			} else {
+				output--;
+			}
 		}
 	} else if (strcmp(interface, wl_seat_interface.name) == 0) {
 		seat = wl_registry_bind(registry, name,
@@ -426,10 +429,6 @@ int main(int argc, char **argv) {
 		fprintf(stderr, "layer_shell not available\n");
 		return 1;
 	}
-	if (wl_output == NULL) {
-		fprintf(stderr, "wl_output not available\n");
-		return 1;
-	}
 
 	cursor_theme = wl_cursor_theme_load(NULL, 16, shm);
 	assert(cursor_theme);

include/rootston/input.h

@@ -30,4 +30,6 @@ bool input_view_has_focus(struct roots_input *input, struct roots_view *view);
 
 struct roots_seat *input_get_seat(struct roots_input *input, char *name);
 
+struct roots_seat *input_last_active_seat(struct roots_input *input);
+
 #endif

include/wlr/types/wlr_layer_shell.h

@@ -27,6 +27,9 @@ struct wlr_layer_shell {
 	struct wl_listener display_destroy;
 
 	struct {
+		 // struct wlr_layer_surface *
+		 // Note: the output may be NULL. In this case, it is your
+		 // responsibility to assign an output before returning.
 		struct wl_signal new_surface;
 	} events;
 

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

@@ -47,12 +47,16 @@
         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"/>
+      <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>

rootston/desktop.c

@@ -326,13 +326,7 @@ bool view_center(struct roots_view *view) {
 
 	struct roots_desktop *desktop = view->desktop;
 	struct roots_input *input = desktop->server->input;
-	struct roots_seat *seat = NULL, *_seat;
-	wl_list_for_each(_seat, &input->seats, link) {
-		if (!seat || (seat->seat->last_event.tv_sec > _seat->seat->last_event.tv_sec &&
-				seat->seat->last_event.tv_nsec > _seat->seat->last_event.tv_nsec)) {
-			seat = _seat;
-		}
-	}
+	struct roots_seat *seat = input_last_active_seat(input);
 	if (!seat) {
 		return false;
 	}

rootston/layer_shell.c

@@ -312,6 +312,18 @@ void handle_layer_shell_surface(struct wl_listener *listener, void *data) {
 		return;
 	}
 
+	if (!layer_surface->output) {
+		struct roots_input *input = desktop->server->input;
+		struct roots_seat *seat = input_last_active_seat(input);
+		assert(seat); // Technically speaking we should handle this case
+		struct wlr_output *output =
+			wlr_output_layout_output_at(desktop->layout,
+					seat->cursor->cursor->x,
+					seat->cursor->cursor->y);
+		assert(output); // And this one
+		layer_surface->output = output;
+	}
+
 	roots_surface->surface_commit.notify = handle_surface_commit;
 	wl_signal_add(&layer_surface->surface->events.commit,
 		&roots_surface->surface_commit);

rootston/seat.c

@@ -999,3 +999,14 @@ void roots_seat_end_compositor_grab(struct roots_seat *seat) {
 
 	cursor->mode = ROOTS_CURSOR_PASSTHROUGH;
 }
+
+struct roots_seat *input_last_active_seat(struct roots_input *input) {
+	struct roots_seat *seat = NULL, *_seat;
+	wl_list_for_each(_seat, &input->seats, link) {
+		if (!seat || (seat->seat->last_event.tv_sec > _seat->seat->last_event.tv_sec &&
+				seat->seat->last_event.tv_nsec > _seat->seat->last_event.tv_nsec)) {
+			seat = _seat;
+		}
+	}
+	return seat;
+}

types/wlr_layer_shell.c

@@ -276,6 +276,7 @@ static void handle_wlr_surface_committed(struct wlr_surface *wlr_surface,
 		surface->added = true;
 		wlr_signal_emit_safe(&surface->shell->events.new_surface,
 				surface);
+		assert(surface->output);
 	}
 	if (surface->configured && wlr_surface_has_buffer(surface->surface) &&
 			!surface->mapped) {
@@ -319,7 +320,9 @@ static void layer_shell_handle_get_layer_surface(struct wl_client *wl_client,
 
 	surface->shell = shell;
 	surface->surface = wlr_surface;
-	surface->output = wlr_output_from_resource(output_resource);
+	if (output_resource) {
+		surface->output = wlr_output_from_resource(output_resource);
+	}
 	surface->resource = wl_resource_create(wl_client,
 		&zwlr_layer_surface_v1_interface,
 		wl_resource_get_version(client_resource),