Set panels' geometries correctly and don't render them explicitly

Panels were explicitly rendered by calling wlc_surface_render in
handle_output_pre_render. Calling wlc_surface_render does not set the
surface's geometry (like wlc_view_set_geometry does). Sway did not call
wlc_view_set_geometry for panels, so wlc defaulted their geometry to be at
the origin. This is not correct for bars unless their location is top.

Furthermore, for a surface to receive pointer events, its mask has to be
set to visible. This causes wlc to render these surfaces, causing panels
and backgrounds to be rendered twice.

This commit makes panels and surfaces visible, sets the correct geometries
and removes the code that explicitly rendered them.

include/extensions.h

@@ -23,6 +23,8 @@ struct panel_config {
 	enum desktop_shell_panel_position panel_position;
 	// used to determine if client is a panel
 	struct wl_client *client;
+	// wlc handle for this panel's surface, not set until panel is created
+	wlc_handle handle;
 };
 
 struct desktop_shell_state {

sway/handlers.c

@@ -33,6 +33,66 @@
 // Event handled by sway and should not be sent to client
 #define EVENT_HANDLED true
 
+static struct panel_config *if_panel_find_config(struct wl_client *client) {
+	int i;
+	for (i = 0; i < desktop_shell.panels->length; i++) {
+		struct panel_config *config = desktop_shell.panels->items[i];
+		if (config->client == client) {
+			return config;
+		}
+	}
+	return NULL;
+}
+
+static struct wlc_geometry compute_panel_geometry(struct panel_config *config) {
+	const struct wlc_size resolution = *wlc_output_get_resolution(config->output);
+	const struct wlc_geometry *old = wlc_view_get_geometry(config->handle);
+	struct wlc_geometry new;
+
+	switch (config->panel_position) {
+	case DESKTOP_SHELL_PANEL_POSITION_TOP:
+		new.origin.x = 0;
+		new.origin.y = 0;
+		new.size.w = resolution.w;
+		new.size.h = old->size.h;
+		break;
+	case DESKTOP_SHELL_PANEL_POSITION_BOTTOM:
+		new.origin.x = 0;
+		new.origin.y = resolution.h - old->size.h;
+		new.size.w = resolution.w;
+		new.size.h = old->size.h;
+		break;
+	case DESKTOP_SHELL_PANEL_POSITION_LEFT:
+		new.origin.x = 0;
+		new.origin.y = 0;
+		new.size.w = old->size.w;
+		new.size.h = resolution.h;
+		break;
+	case DESKTOP_SHELL_PANEL_POSITION_RIGHT:
+		new.origin.x = resolution.w - old->size.w;
+		new.origin.y = 0;
+		new.size.w = old->size.w;
+		new.size.h = resolution.h;
+		break;
+	}
+
+	return new;
+}
+
+static void update_panel_geometry(struct panel_config *config) {
+	struct wlc_geometry geometry = compute_panel_geometry(config);
+	wlc_view_set_geometry(config->handle, 0, &geometry);
+}
+
+static void update_panel_geometries(wlc_handle output) {
+	for (int i = 0; i < desktop_shell.panels->length; i++) {
+		struct panel_config *config = desktop_shell.panels->items[i];
+		if (config->output == output) {
+			update_panel_geometry(config);
+		}
+	}
+}
+
 /* Handles */
 
 static bool handle_input_created(struct libinput_device *device) {
@@ -119,32 +179,6 @@ static void handle_output_pre_render(wlc_handle output) {
 			break;
 		}
 	}
-
-	for (i = 0; i < desktop_shell.panels->length; ++i) {
-		struct panel_config *config = desktop_shell.panels->items[i];
-		if (config->output == output) {
-			struct wlc_size size = *wlc_surface_get_size(config->surface);
-			struct wlc_geometry geo = {
-				.size = size
-			};
-			switch (config->panel_position) {
-			case DESKTOP_SHELL_PANEL_POSITION_TOP:
-				geo.origin = (struct wlc_point){ 0, 0 };
-				break;
-			case DESKTOP_SHELL_PANEL_POSITION_BOTTOM:
-				geo.origin = (struct wlc_point){ 0, resolution.h - size.h };
-				break;
-			case DESKTOP_SHELL_PANEL_POSITION_LEFT:
-				geo.origin = (struct wlc_point){ 0, 0 };
-				break;
-			case DESKTOP_SHELL_PANEL_POSITION_RIGHT:
-				geo.origin = (struct wlc_point){ resolution.w - size.w, 0 };
-				break;
-			}
-			wlc_surface_render(config->surface, &geo);
-			break;
-		}
-	}
 }
 
 static void handle_output_post_render(wlc_handle output) {
@@ -158,10 +192,16 @@ static void handle_view_pre_render(wlc_handle view) {
 
 static void handle_output_resolution_change(wlc_handle output, const struct wlc_size *from, const struct wlc_size *to) {
 	sway_log(L_DEBUG, "Output %u resolution changed to %d x %d", (unsigned int)output, to->w, to->h);
+
 	swayc_t *c = swayc_by_handle(output);
-	if (!c) return;
+	if (!c) {
+		return;
+	}
 	c->width = to->w;
 	c->height = to->h;
+
+	update_panel_geometries(output);
+
 	arrange_windows(&root_container, -1, -1);
 }
 
@@ -176,17 +216,6 @@ static void handle_output_focused(wlc_handle output, bool focus) {
 	}
 }
 
-static bool client_is_panel(struct wl_client *client) {
-	int i;
-	for (i = 0; i < desktop_shell.panels->length; i++) {
-		struct panel_config *config = desktop_shell.panels->items[i];
-		if (config->client == client) {
-			return true;
-		}
-	}
-	return false;
-}
-
 static void ws_cleanup() {
 	swayc_t *op, *ws;
 	int i = 0, j;
@@ -217,8 +246,14 @@ static bool handle_view_created(wlc_handle handle) {
 	bool return_to_workspace = false;
 	struct wl_client *client = wlc_view_get_wl_client(handle);
 	pid_t pid;
+	struct panel_config *panel_config = NULL;
 
-	if (client_is_panel(client)) {
+	panel_config = if_panel_find_config(client);
+	if (panel_config) {
+		panel_config->handle = handle;
+		update_panel_geometry(panel_config);
+		wlc_view_set_mask(handle, VISIBLE);
+		wlc_view_set_output(handle, panel_config->output);
 		return true;
 	}