[gtk+] wayland: Stop using ::monitors-changed

[Matthias Clasen <matthiasc src gnome org>]

commit e424dcb049b2662245e75d4bfa9986d2f8454347
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Oct 31 21:48:58 2017 -0400

    wayland: Stop using ::monitors-changed
    
    Instead of connecting to this signal for every single window,
    walk the window tree from the root window.

 gdk/wayland/gdkprivate-wayland.h |    3 +++
 gdk/wayland/gdkscreen-wayland.c  |   18 +++++-------------
 gdk/wayland/gdkwindow-wayland.c  |   30 ++++++++++++------------------
 3 files changed, 20 insertions(+), 31 deletions(-)
---
diff --git a/gdk/wayland/gdkprivate-wayland.h b/gdk/wayland/gdkprivate-wayland.h
index 1a45bad..20b77ee 100644
--- a/gdk/wayland/gdkprivate-wayland.h
+++ b/gdk/wayland/gdkprivate-wayland.h
@@ -290,4 +290,7 @@ void gdk_wayland_window_inhibit_shortcuts (GdkWindow *window,
 void gdk_wayland_window_restore_shortcuts (GdkWindow *window,
                                            GdkSeat   *gdk_seat);
 
+void window_update_scale (GdkWindow *window);
+
+
 #endif /* __GDK_PRIVATE_WAYLAND_H__ */
diff --git a/gdk/wayland/gdkscreen-wayland.c b/gdk/wayland/gdkscreen-wayland.c
index bf11e35..9e8d297 100644
--- a/gdk/wayland/gdkscreen-wayland.c
+++ b/gdk/wayland/gdkscreen-wayland.c
@@ -698,8 +698,7 @@ output_handle_geometry (void             *data,
   if (GDK_MONITOR (monitor)->geometry.width != 0 && monitor->version < OUTPUT_VERSION_WITH_DONE)
     {
       GdkDisplay *display = GDK_MONITOR (monitor)->display;
-      GdkWaylandScreen *screen = GDK_WAYLAND_SCREEN (gdk_display_get_default_screen (display));
-      g_signal_emit_by_name (screen, "monitors-changed");
+      window_update_scale (gdk_display_get_root_window (display));
     }
 }
 
@@ -709,7 +708,6 @@ output_handle_done (void             *data,
 {
   GdkWaylandMonitor *monitor = (GdkWaylandMonitor *)data;
   GdkDisplay *display = gdk_monitor_get_display (GDK_MONITOR (monitor));
-  GdkWaylandScreen *screen_wayland = GDK_WAYLAND_SCREEN (gdk_display_get_default_screen (display));
 
   GDK_NOTE (MISC,
             g_message ("handle done output %d", monitor->id));
@@ -721,7 +719,7 @@ output_handle_done (void             *data,
       gdk_display_monitor_added (display, GDK_MONITOR (monitor));
     }
 
-  g_signal_emit_by_name (screen_wayland, "monitors-changed");
+  window_update_scale (gdk_display_get_root_window (display));
 }
 
 static void
@@ -748,10 +746,7 @@ output_handle_scale (void             *data,
   gdk_monitor_set_size (GDK_MONITOR (monitor), width / scale, height / scale);
 
   if (GDK_MONITOR (monitor)->geometry.width != 0 && monitor->version < OUTPUT_VERSION_WITH_DONE)
-    {
-      GdkScreen *screen = gdk_display_get_default_screen (GDK_MONITOR (monitor)->display);
-      g_signal_emit_by_name (screen, "monitors-changed");
-    }
+    window_update_scale (gdk_display_get_root_window (GDK_MONITOR (monitor)->display));
 }
 
 static void
@@ -777,10 +772,7 @@ output_handle_mode (void             *data,
   gdk_monitor_set_refresh_rate (GDK_MONITOR (monitor), refresh);
 
   if (width != 0 && monitor->version < OUTPUT_VERSION_WITH_DONE)
-    {
-      GdkScreen *screen = gdk_display_get_default_screen (GDK_MONITOR (monitor)->display);
-      g_signal_emit_by_name (screen, "monitors-changed");
-    }
+    window_update_scale (gdk_display_get_root_window (GDK_MONITOR (monitor)->display));
 }
 
 static const struct wl_output_listener output_listener =
@@ -879,8 +871,8 @@ _gdk_wayland_screen_remove_output (GdkScreen *screen,
       g_object_ref (monitor);
       g_ptr_array_remove (display_wayland->monitors, monitor);
       gdk_display_monitor_removed (GDK_DISPLAY (display_wayland), GDK_MONITOR (monitor));
+      window_update_scale (gdk_display_get_root_window (GDK_MONITOR (monitor)->display));
       g_object_unref (monitor);
-      g_signal_emit_by_name (screen_wayland, "monitors-changed");
     }
 }
 
diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index bb070d3..0dc12ab 100644
--- a/gdk/wayland/gdkwindow-wayland.c
+++ b/gdk/wayland/gdkwindow-wayland.c
@@ -614,14 +614,14 @@ on_frame_clock_after_paint (GdkFrameClock *clock,
   g_signal_emit (impl, signals[COMMITTED], 0);
 }
 
-static void
+void
 window_update_scale (GdkWindow *window)
 {
   GdkWindowImplWayland *impl = GDK_WINDOW_IMPL_WAYLAND (window->impl);
-  GdkWaylandDisplay *display_wayland =
-    GDK_WAYLAND_DISPLAY (gdk_window_get_display (window));
+  GdkWaylandDisplay *display_wayland = GDK_WAYLAND_DISPLAY (gdk_window_get_display (window));
   guint32 scale;
   GSList *l;
+  GList *children, *c;
 
   if (display_wayland->compositor_version < WL_SURFACE_HAS_BUFFER_SCALE)
     {
@@ -639,16 +639,16 @@ window_update_scale (GdkWindow *window)
 
   /* Notify app that scale changed */
   gdk_wayland_window_maybe_configure (window, window->width, window->height, scale);
-}
 
-static void
-on_monitors_changed (GdkScreen *screen,
-                     GdkWindow *window)
-{
-  window_update_scale (window);
+  children = gdk_window_get_children (window);
+  for (c = children; c; c = c->next)
+    {
+      GdkWindow *child = c->data;
+      window_update_scale (child);
+    }
+  g_list_free (children);
 }
 
-
 static void gdk_wayland_window_create_surface (GdkWindow *window);
 
 void
@@ -702,14 +702,8 @@ _gdk_wayland_display_create_window_impl (GdkDisplay    *display,
   gdk_wayland_window_create_surface (window);
 
   frame_clock = gdk_window_get_frame_clock (window);
-
-  g_signal_connect (frame_clock, "before-paint",
-                    G_CALLBACK (on_frame_clock_before_paint), window);
-  g_signal_connect (frame_clock, "after-paint",
-                    G_CALLBACK (on_frame_clock_after_paint), window);
-
-  g_signal_connect (gdk_display_get_default_screen (display), "monitors-changed",
-                    G_CALLBACK (on_monitors_changed), window);
+  g_signal_connect (frame_clock, "before-paint", G_CALLBACK (on_frame_clock_before_paint), window);
+  g_signal_connect (frame_clock, "after-paint", G_CALLBACK (on_frame_clock_after_paint), window);
 }
 
 static void