xwayland: render children window in fullscreen

include/wlr/xwayland.h

@@ -98,9 +98,12 @@ struct wlr_xwayland_surface {
 	char *title;
 	char *class;
 	char *instance;
-	struct wlr_xwayland_surface *parent;
 	pid_t pid;
 
+	struct wl_list children; // wlr_xwayland_surface::parent_link
+	struct wlr_xwayland_surface *parent;
+	struct wl_list parent_link; // wlr_xwayland_surface::children
+
 	xcb_atom_t *window_type;
 	size_t window_type_len;
 

rootston/output.c

@@ -169,6 +169,19 @@ static void render_wl_shell_surface(struct wlr_wl_shell_surface *surface,
 	}
 }
 
+static void render_xwayland_children(struct wlr_xwayland_surface *surface,
+		struct roots_desktop *desktop, struct wlr_output *wlr_output,
+		struct timespec *when) {
+	struct wlr_xwayland_surface *child;
+	wl_list_for_each(child, &surface->children, parent_link) {
+		if (child->surface != NULL && child->added) {
+			render_surface(child->surface, desktop, wlr_output, when,
+				child->x, child->y, 0);
+		}
+		render_xwayland_children(child, desktop, wlr_output, when);
+	}
+}
+
 static void render_view(struct roots_view *view, struct roots_desktop *desktop,
 		struct wlr_output *wlr_output, struct timespec *when) {
 	switch (view->type) {
@@ -200,7 +213,7 @@ static bool has_standalone_surface(struct roots_view *view) {
 	case ROOTS_WL_SHELL_VIEW:
 		return wl_list_empty(&view->wl_shell_surface->popups);
 	case ROOTS_XWAYLAND_VIEW:
-		return true;
+		return wl_list_empty(&view->xwayland_surface->children);
 	}
 	return true;
 }
@@ -218,27 +231,36 @@ static void output_frame_notify(struct wl_listener *listener, void *data) {
 	wlr_renderer_begin(server->renderer, wlr_output);
 
 	if (output->fullscreen_view != NULL) {
+		struct roots_view *view = output->fullscreen_view;
+
 		// Make sure the view is centered on screen
 		const struct wlr_box *output_box =
 			wlr_output_layout_get_box(desktop->layout, wlr_output);
 		struct wlr_box view_box;
-		view_get_box(output->fullscreen_view, &view_box);
+		view_get_box(view, &view_box);
 		double view_x = (double)(output_box->width - view_box.width) / 2 +
 			output_box->x;
 		double view_y = (double)(output_box->height - view_box.height) / 2 +
 			output_box->y;
-		view_move(output->fullscreen_view, view_x, view_y);
+		view_move(view, view_x, view_y);
 
-		if (has_standalone_surface(output->fullscreen_view)) {
-			wlr_output_set_fullscreen_surface(wlr_output,
-				output->fullscreen_view->wlr_surface);
+		if (has_standalone_surface(view)) {
+			wlr_output_set_fullscreen_surface(wlr_output, view->wlr_surface);
 		} else {
 			wlr_output_set_fullscreen_surface(wlr_output, NULL);
 
 			glClearColor(0, 0, 0, 0);
 			glClear(GL_COLOR_BUFFER_BIT);
 
-			render_view(output->fullscreen_view, desktop, wlr_output, &now);
+			render_view(view, desktop, wlr_output, &now);
+
+			// During normal rendering the xwayland window tree isn't traversed
+			// because all windows are rendered. Here we only want to render
+			// the fullscreen window's children so we have to traverse the tree.
+			if (view->type == ROOTS_XWAYLAND_VIEW) {
+				render_xwayland_children(view->xwayland_surface, desktop,
+					wlr_output, &now);
+			}
 		}
 		wlr_renderer_end(server->renderer);
 		wlr_output_swap_buffers(wlr_output);

xwayland/xwm.c

@@ -96,6 +96,8 @@ static struct wlr_xwayland_surface *wlr_xwayland_surface_create(
 	surface->height = height;
 	surface->override_redirect = override_redirect;
 	wl_list_insert(&xwm->surfaces, &surface->link);
+	wl_list_init(&surface->children);
+	wl_list_init(&surface->parent_link);
 	wl_signal_init(&surface->events.destroy);
 	wl_signal_init(&surface->events.request_configure);
 	wl_signal_init(&surface->events.request_move);
@@ -215,6 +217,7 @@ static void wlr_xwayland_surface_destroy(
 	}
 
 	wl_list_remove(&xsurface->link);
+	wl_list_remove(&xsurface->parent_link);
 
 	if (xsurface->surface_id) {
 		wl_list_remove(&xsurface->unpaired_link);
@@ -305,6 +308,13 @@ static void read_surface_parent(struct wlr_xwm *xwm,
 		xsurface->parent = NULL;
 	}
 
+	wl_list_remove(&xsurface->parent_link);
+	if (xsurface->parent != NULL) {
+		wl_list_insert(&xsurface->parent->children, &xsurface->parent_link);
+	} else {
+		wl_list_init(&xsurface->parent_link);
+	}
+
 	wlr_log(L_DEBUG, "XCB_ATOM_WM_TRANSIENT_FOR: %p", xid);
 	wl_signal_emit(&xsurface->events.set_parent, xsurface);
 }