osd: add multi-monitor support

Adds `output` attribute to control which monitor(s) display the window
switcher OSD. Supports three modes:
- "all": display on all monitors (default)
- "pointer": display on monitor with mouse cursor
- "keyboard": display on monitor with keyboard focus

The configuration structure is also refactored to nest OSD-specific
settings (show, style, output, thumbnailLabelFormat) under an <osd>
element within <windowSwitcher>, improving logical organization.

docs/labwc-config.5.scd

@@ -339,7 +339,8 @@ this is for compatibility with Openbox.
 ## WINDOW SWITCHER
 
 ```
-<windowSwitcher show="yes" style="classic" preview="yes" outlines="yes" allWorkspaces="no" thumbnailLabelFormat="%T">
+<windowSwitcher preview="yes" outlines="yes" allWorkspaces="no">
+  <osd show="yes" style="classic" output="all" thumbnailLabelFormat="%T" />
   <fields>
     <field content="icon" width="5%" />
     <field content="desktop_entry_name" width="30%" />
@@ -348,14 +349,7 @@ this is for compatibility with Openbox.
 </windowSwitcher>
 ```
 
-*<windowSwitcher show="" style="" preview="" outlines="" allWorkspaces="" unshade="" thumbnailLabelFormat="">*
+*<windowSwitcher preview="" outlines="" allWorkspaces="" unshade="">*
-	*show* [yes|no] Draw the OnScreenDisplay when switching between
-	windows. Default is yes.
-
-	*style* [classic|thumbnail] Configures the style of the OnScreenDisplay.
-	"classic" displays window information like icons and titles in a vertical list.
-	"thumbnail" shows window thumbnail, icon and title in grids.
-
 	*preview* [yes|no] Preview the contents of the selected window when
 	switching between windows. Default is yes.
 
@@ -369,12 +363,26 @@ this is for compatibility with Openbox.
 	*unshade* [yes|no] Temporarily unshade windows when switching between
 	them and permanently unshade on the final selection. Default is yes.
 
+*<osd show="" style="" output="" thumbnailLabelFormat="" />*
+	*show* [yes|no] Draw the OnScreenDisplay when switching between
+	windows. Default is yes.
+
+	*style* [classic|thumbnail] Configures the style of the OSD.
+	"classic" displays window information like icons and titles in a vertical list.
+	"thumbnail" shows window thumbnail, icon and title in grids.
+
+	*output* [all|pointer|keyboard] Configures which monitor(s) show the OSD.
+	"all" displays the OSD on all monitors.
+	"pointer" displays the OSD on the monitor containing the mouse pointer.
+	"keyboard" displays the OSD on the monitor with keyboard focus.
+	Default is "all".
+
 	*thumbnailLabelFormat* Format to be used for the thumbnail label according to *custom*
-	field below, only applied when using *<windowSwitcher style="thumbnail" />*.
+	field below, only applied when using *<osd style="thumbnail" />*.
 	Default is "%T".
 
 *<windowSwitcher><fields><field content="" width="%">*
-	Define window switcher fields when using *<windowSwitcher style="classic" />*.
+	Define window switcher fields when using *<osd style="classic" />*.
 
 	*content* defines what the field shows and can be any of:
 

docs/rc.xml.all

@@ -77,8 +77,8 @@
     </font>
   </theme>
 
-  <windowSwitcher show="yes" style="classic" preview="yes"
+  <windowSwitcher preview="yes" outlines="yes" allWorkspaces="no" unshade="yes">
-      outlines="yes" allWorkspaces="no" unshade="yes">
+    <osd show="yes" style="classic" output="all" thumbnailLabelFormat="%T" />
     <fields>
       <field content="icon" width="5%" />
       <field content="desktop_entry_name" width="30%" />
@@ -98,7 +98,8 @@
     Some contents are fixed-length and others are variable-length.
     See "man 5 labwc-config" for details.
 
-    <windowSwitcher show="yes" preview="no" outlines="no" allWorkspaces="yes">
+    <windowSwitcher preview="no" outlines="no" allWorkspaces="yes">
+      <osd show="yes" />
       <fields>
         <field content="workspace" width="5%" />
         <field content="state" width="3%" />
@@ -118,7 +119,8 @@
     then workspace name, then identifier/app-id, then the window title.
     It uses 100% of OSD window width.
 
-    <windowSwitcher show="yes" preview="no" outlines="no" allWorkspaces="yes">
+    <windowSwitcher preview="no" outlines="no" allWorkspaces="yes">
+      <osd show="yes" />
       <fields>
         <field content="custom" format="foobar %b %3s %-10o %-20W %-10i %t" width="100%" />
       </fields>

include/config/rcxml.h

@@ -183,6 +183,7 @@ struct rcxml {
 		enum lab_view_criteria criteria;
 		struct wl_list fields;  /* struct window_switcher_field.link */
 		enum window_switcher_style style;
+		enum osd_output_criteria output_criteria;
 		char *thumbnail_label_format;
 	} window_switcher;
 

include/config/types.h

@@ -112,4 +112,10 @@ enum window_switcher_style {
 	WINDOW_SWITCHER_THUMBNAIL,
 };
 
+enum osd_output_criteria {
+	OSD_OUTPUT_ALL,
+	OSD_OUTPUT_POINTER,
+	OSD_OUTPUT_KEYBOARD,
+};
+
 #endif /* LABWC_CONFIG_TYPES_H */

src/config/rcxml.c

@@ -1068,7 +1068,7 @@ entry(xmlNode *node, char *nodename, char *content)
 		load_default_mouse_bindings();
 	} else if (!strcasecmp(nodename, "prefix.desktops")) {
 		xstrdup_replace(rc.workspace_config.prefix, content);
-	} else if (!strcasecmp(nodename, "thumbnailLabelFormat.windowSwitcher")) {
+	} else if (!strcasecmp(nodename, "thumbnailLabelFormat.osd.windowSwitcher")) {
 		xstrdup_replace(rc.window_switcher.thumbnail_label_format, content);
 
 	} else if (!lab_xml_node_is_leaf(node)) {
@@ -1201,15 +1201,50 @@ entry(xmlNode *node, char *nodename, char *content)
 			wlr_log(WLR_ERROR, "ignoring invalid value for notifyClient");
 		}
 
-	/* <windowSwitcher show="" preview="" outlines="" /> */
+	/*
+	 * <windowSwitcher preview="" outlines="">
+	 *   <osd show="" style="" output="" thumbnailLabelFormat="" />
+	 * </windowSwitcher>
+	 *
+	 * thumnailLabelFormat is handled above to allow for an empty value
+	 */
+	} else if (!strcasecmp(nodename, "show.osd.windowSwitcher")) {
+		set_bool(content, &rc.window_switcher.show);
+	} else if (!strcasecmp(nodename, "style.osd.windowSwitcher")) {
+		if (!strcasecmp(content, "classic")) {
+			rc.window_switcher.style = WINDOW_SWITCHER_CLASSIC;
+		} else if (!strcasecmp(content, "thumbnail")) {
+			rc.window_switcher.style = WINDOW_SWITCHER_THUMBNAIL;
+		} else {
+			wlr_log(WLR_ERROR, "Invalid windowSwitcher style %s: "
+				"should be one of classic|thumbnail", content);
+		}
+	} else if (!strcasecmp(nodename, "output.osd.windowSwitcher")) {
+		if (!strcasecmp(content, "all")) {
+			rc.window_switcher.output_criteria = OSD_OUTPUT_ALL;
+		} else if (!strcasecmp(content, "pointer")) {
+			rc.window_switcher.output_criteria = OSD_OUTPUT_POINTER;
+		} else if (!strcasecmp(content, "keyboard")) {
+			rc.window_switcher.output_criteria = OSD_OUTPUT_KEYBOARD;
+		} else {
+			wlr_log(WLR_ERROR, "Invalid windowSwitcher output %s: "
+				"should be one of all|pointer|keyboard", content);
+		}
+
+	/* The following two are for backward compatibility only. */
 	} else if (!strcasecmp(nodename, "show.windowSwitcher")) {
 		set_bool(content, &rc.window_switcher.show);
+		wlr_log(WLR_ERROR, "<windowSwitcher show=\"\" /> is deprecated."
+			" Use <osd show=\"\" />");
 	} else if (!strcasecmp(nodename, "style.windowSwitcher")) {
 		if (!strcasecmp(content, "classic")) {
 			rc.window_switcher.style = WINDOW_SWITCHER_CLASSIC;
 		} else if (!strcasecmp(content, "thumbnail")) {
 			rc.window_switcher.style = WINDOW_SWITCHER_THUMBNAIL;
 		}
+		wlr_log(WLR_ERROR, "<windowSwitcher style=\"\" /> is deprecated."
+			" Use <osd style=\"\" />");
+
 	} else if (!strcasecmp(nodename, "preview.windowSwitcher")) {
 		set_bool(content, &rc.window_switcher.preview);
 	} else if (!strcasecmp(nodename, "outlines.windowSwitcher")) {
@@ -1431,6 +1466,7 @@ rcxml_init(void)
 
 	rc.window_switcher.show = true;
 	rc.window_switcher.style = WINDOW_SWITCHER_CLASSIC;
+	rc.window_switcher.output_criteria = OSD_OUTPUT_ALL;
 	rc.window_switcher.thumbnail_label_format = xstrdup("%T");
 	rc.window_switcher.preview = true;
 	rc.window_switcher.outlines = true;

src/osd/osd.c

@@ -294,6 +294,20 @@ preview_cycled_view(struct view *view)
 	wlr_scene_node_raise_to_top(osd_state->preview_node);
 }
 
+static void
+update_osd_on_output(struct server *server, struct output *output,
+	struct osd_impl *osd_impl, struct wl_array *views)
+{
+	if (!output_is_usable(output)) {
+		return;
+	}
+	if (!output->osd_scene.tree) {
+		osd_impl->create(output, views);
+		assert(output->osd_scene.tree);
+	}
+	osd_impl->update(output);
+}
+
 static void
 update_osd(struct server *server)
 {
@@ -318,16 +332,29 @@ update_osd(struct server *server)
 
 	if (rc.window_switcher.show) {
 		/* Display the actual OSD */
+		switch (rc.window_switcher.output_criteria) {
+		case OSD_OUTPUT_ALL: {
 				struct output *output;
 				wl_list_for_each(output, &server->outputs, link) {
-			if (!output_is_usable(output)) {
+					update_osd_on_output(server, output, osd_impl, &views);
-				continue;
 				}
-			if (!output->osd_scene.tree) {
+				break;
-				osd_impl->create(output, &views);
+			}
-				assert(output->osd_scene.tree);
+		case OSD_OUTPUT_POINTER:
+			update_osd_on_output(server,
+				output_nearest_to_cursor(server), osd_impl, &views);
+			break;
+		case OSD_OUTPUT_KEYBOARD: {
+				struct output *output;
+				if (server->active_view) {
+					output = server->active_view->output;
+				} else {
+					/* Fallback to pointer, if there is no active_view */
+					output = output_nearest_to_cursor(server);
+				}
+				update_osd_on_output(server, output, osd_impl, &views);
+				break;
 			}
-			osd_impl->update(output);
 		}
 	}