Use daemon to show display labels

data/Display.css

@@ -9,11 +9,6 @@
     -gtk-icon-palette: warning white;
 }
 
-/* Don't use alpha for the on-screen identifier */
-window.colored {
-    background-color: alpha (@BG_COLOR, 0.8);
-}
-
 widget.colored {
     border: 1px solid mix(@BG_COLOR_ALPHA, @TEXT_COLOR, 0.3);
 }

src/Interfaces/GalaDBus.vala

@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.0-or-later
+ * SPDX-FileCopyrightText: 2024 elementary, Inc. (https://elementary.io)
+ */
+
+[DBus (name = "org.pantheon.gala.daemon")]
+public interface GalaDBus : Object {
+    public abstract void show_monitor_labels (MonitorLabelInfo[] label_infos) throws GLib.DBusError, GLib.IOError;
+    public abstract void hide_monitor_labels () throws GLib.DBusError, GLib.IOError;
+}
+
+public struct MonitorLabelInfo {
+    public int monitor;
+    public string label;
+    public string background_color;
+    public string text_color;
+    public int x;
+    public int y;
+}

src/Widgets/DisplayWidget.vala

@@ -1,5 +1,5 @@
 /*-
- * Copyright 2014–2021 elementary, Inc.
+ * Copyright 2014–2024 elementary, Inc.
  *           2014–2018 Corentin Noël <corentin@elementary.io>
  *
  * This software is free software; you can redistribute it and/or
@@ -35,6 +35,8 @@ public class Display.DisplayWidget : Gtk.EventBox {
     public signal void active_changed ();
 
     public Display.VirtualMonitor virtual_monitor { get; construct; }
+    public string bg_color { get; construct; }
+    public string text_color { get; construct; }
 
     public double window_ratio { get; private set; default = 1.0; }
     public int delta_x { get; set; default = 0; }
@@ -45,7 +47,6 @@ public class Display.DisplayWidget : Gtk.EventBox {
     private double start_y = 0;
     private bool holding = false;
 
-    public DisplayWindow display_window { get; private set; }
     public Gtk.Button primary_image { get; private set; }
     public Gtk.MenuButton toggle_settings { get; private set; }
 
@@ -85,19 +86,19 @@ public class Display.DisplayWidget : Gtk.EventBox {
         TOTAL
     }
 
-    public DisplayWidget (Display.VirtualMonitor virtual_monitor) {
-        Object (virtual_monitor: virtual_monitor);
+    public DisplayWidget (Display.VirtualMonitor virtual_monitor, string bg_color, string text_color) {
+        Object (
+            virtual_monitor: virtual_monitor,
+            bg_color: bg_color,
+            text_color: text_color
+        );
     }
 
     construct {
         events |= Gdk.EventMask.BUTTON_PRESS_MASK;
         events |= Gdk.EventMask.BUTTON_RELEASE_MASK;
         events |= Gdk.EventMask.POINTER_MOTION_MASK;
 
-        display_window = new DisplayWindow (virtual_monitor) {
-            attached_to = this
-        };
-
         virtual_monitor.get_current_mode_size (out real_width, out real_height);
 
         primary_image = new Gtk.Button.from_icon_name ("non-starred-symbolic") {
@@ -291,8 +292,6 @@ public class Display.DisplayWidget : Gtk.EventBox {
         set_primary (virtual_monitor.primary);
         add (grid);
 
-        destroy.connect (() => display_window.destroy ());
-
         use_switch.bind_property ("active", resolution_combobox, "sensitive");
         use_switch.bind_property ("active", rotation_combobox, "sensitive");
         use_switch.bind_property ("active", refresh_combobox, "sensitive");

src/Widgets/DisplaysOverlay.vala

@@ -34,6 +34,7 @@ public class Display.DisplaysOverlay : Gtk.Overlay {
     private int default_y_margin = 0;
 
     private unowned Display.MonitorManager monitor_manager;
+    private static GalaDBus gala_dbus = null;
     public int active_displays { get; set; default = 0; }
 
     private List<DisplayWidget> display_widgets;
@@ -82,6 +83,20 @@ public class Display.DisplaysOverlay : Gtk.Overlay {
     static construct {
         display_provider = new Gtk.CssProvider ();
         display_provider.load_from_resource ("io/elementary/switchboard/display/Display.css");
+
+        GLib.Bus.get_proxy.begin<GalaDBus> (
+            GLib.BusType.SESSION,
+            "org.pantheon.gala.daemon",
+            "/org/pantheon/gala/daemon",
+            GLib.DBusProxyFlags.NONE,
+            null,
+            (obj, res) => {
+            try {
+                gala_dbus = GLib.Bus.get_proxy.end (res);
+            } catch (GLib.Error e) {
+                critical (e.message);
+            }
+        });
     }
 
     public override bool get_child_position (Gtk.Widget widget, out Gdk.Rectangle allocation) {
@@ -129,22 +144,39 @@ public class Display.DisplaysOverlay : Gtk.Overlay {
         scanning = false;
     }
 
-    public void show_windows () {
+    public void show_windows () requires (gala_dbus != null) {
         if (monitor_manager.is_mirrored) {
             return;
         }
 
+        MonitorLabelInfo[] label_infos = {};
+
         foreach (unowned var widget in display_widgets) {
             if (widget.virtual_monitor.is_active) {
-                widget.display_window.show_all ();
+                label_infos += MonitorLabelInfo () {
+                    monitor = label_infos.length,
+                    label = widget.virtual_monitor.get_display_name (),
+                    background_color = widget.bg_color,
+                    text_color = widget.text_color,
+                    x = widget.virtual_monitor.current_x,
+                    y = widget.virtual_monitor.current_y
+                };
             }
         }
+
+        try {
+            gala_dbus.show_monitor_labels (label_infos);
+        } catch (Error e) {
+            warning ("Couldn't show monitor labels: %s", e.message);
+        }
     }
 
-    public void hide_windows () {
-        foreach (unowned var widget in display_widgets) {
-            widget.display_window.hide ();
-        };
+    public void hide_windows () requires (gala_dbus != null) {
+        try {
+            gala_dbus.hide_monitor_labels ();
+        } catch (Error e) {
+            warning ("Couldn't hide monitor labels: %s", e.message);
+        }
     }
 
     private void change_active_displays_sensitivity () {
@@ -187,16 +219,16 @@ public class Display.DisplaysOverlay : Gtk.Overlay {
     }
 
     private void add_output (Display.VirtualMonitor virtual_monitor) {
-        var display_widget = new DisplayWidget (virtual_monitor);
         current_allocated_width = 0;
         current_allocated_height = 0;
+
+        var color_number = (get_children ().length () - 2) % 7;
+        var display_widget = new DisplayWidget (virtual_monitor, colors[color_number], text_colors[color_number]);
         add_overlay (display_widget);
         display_widgets.append (display_widget);
 
         var provider = new Gtk.CssProvider ();
         try {
-            var color_number = (get_children ().length () - 2) % 7;
-
             var colored_css = COLORED_STYLE_CSS.printf (colors[color_number], text_colors[color_number]);
             provider.load_from_data (colored_css, colored_css.length);
 
@@ -205,11 +237,6 @@ public class Display.DisplaysOverlay : Gtk.Overlay {
             context.add_provider (display_provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
             context.add_class ("colored");
 
-            context = display_widget.display_window.get_style_context ();
-            context.add_provider (provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
-            context.add_provider (display_provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
-            context.add_class ("colored");
-
             context = display_widget.primary_image.get_style_context ();
             context.add_provider (provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
             context.add_provider (display_provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
@@ -243,7 +270,7 @@ public class Display.DisplaysOverlay : Gtk.Overlay {
         });
 
         if (!monitor_manager.is_mirrored && virtual_monitor.is_active) {
-            display_widget.display_window.show_all ();
+            show_windows ();
         }
 
         display_widget.end_grab.connect ((delta_x, delta_y) => {

src/meson.build

@@ -2,6 +2,7 @@ plug_files = files(
     'Utils.vala',
     'SettingsDaemon.vala',
     'DisplayPlug.vala',
+    'Interfaces/GalaDBus.vala',
     'Interfaces/NightLightManager.vala',
     'Interfaces/MutterDisplayConfig.vala',
     'Objects/VirtualMonitor.vala',
@@ -11,7 +12,6 @@ plug_files = files(
     'Views/NightLightView.vala',
     'Views/DisplaysView.vala',
     'Views' / 'FiltersView.vala',
-    'Widgets/DisplayWindow.vala',
     'Widgets/DisplayWidget.vala',
     'Widgets/DisplaysOverlay.vala',
 )