[gtk/x11-damage-reporting] x11: Fix damage reporting

[Matthias Clasen <matthiasc src gnome org>]

commit dd4293b67ab1b586ba49d52eb83b49412cefaabe
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Mar 14 17:25:55 2021 -0400

    x11: Fix damage reporting

 gdk/x11/gdksurface-x11.c | 44 +++++++++++++++++++++++++++-----------------
 gdk/x11/gdksurface-x11.h |  1 -
 2 files changed, 27 insertions(+), 18 deletions(-)
---
diff --git a/gdk/x11/gdksurface-x11.c b/gdk/x11/gdksurface-x11.c
index 92a0a23d6c..b7abd5135e 100644
--- a/gdk/x11/gdksurface-x11.c
+++ b/gdk/x11/gdksurface-x11.c
@@ -179,19 +179,29 @@ _gdk_x11_surface_get_toplevel (GdkSurface *surface)
 
 /**
  * _gdk_x11_surface_update_size:
- * @impl: a #GdkX11Surface.
- * 
+ * @impl: a #GdkX11Surface
+ *
  * Updates the state of the surface (in particular the drawable's
  * cairo surface) when its size has changed.
  **/
-void
-_gdk_x11_surface_update_size (GdkX11Surface *impl)
+static void
+_gdk_x11_surface_update_size (GdkX11Surface *impl,
+                              int            width,
+                              int            height)
 {
+  GdkSurface *surface = GDK_SURFACE (impl);
+
+  if (surface->width == width && surface->height == height)
+    return;
+
+  surface->width = width;
+  surface->height = height;
+  _gdk_surface_update_size (surface);
+
   if (impl->cairo_surface)
-    {
-      cairo_xlib_surface_set_size (impl->cairo_surface,
-                                   impl->unscaled_width, impl->unscaled_height);
-    }
+    cairo_xlib_surface_set_size (impl->cairo_surface,
+                                 impl->unscaled_width,
+                                 impl->unscaled_height);
 }
 
 static void
@@ -385,10 +395,9 @@ gdk_x11_surface_compute_size (GdkSurface *surface)
 
       if (surface->resize_count == 0)
         {
-          surface->width = impl->next_layout.configured_width;
-          surface->height = impl->next_layout.configured_height;
-          _gdk_surface_update_size (surface);
-          _gdk_x11_surface_update_size (impl);
+          _gdk_x11_surface_update_size (impl,
+                                        impl->next_layout.configured_width,
+                                        impl->next_layout.configured_height);
         }
 
       impl->next_layout.surface_geometry_dirty = FALSE;
@@ -396,11 +405,9 @@ gdk_x11_surface_compute_size (GdkSurface *surface)
     }
   else
     {
-      surface->width = impl->next_layout.configured_width;
-      surface->height = impl->next_layout.configured_height;
-
-      _gdk_surface_update_size (surface);
-      _gdk_x11_surface_update_size (impl);
+      _gdk_x11_surface_update_size (impl,
+                                    impl->next_layout.configured_width,
+                                    impl->next_layout.configured_height);
 
       impl->next_layout.surface_geometry_dirty = FALSE;
     }
@@ -1991,6 +1998,9 @@ _gdk_x11_surface_set_surface_scale (GdkSurface *surface,
 
   impl = GDK_X11_SURFACE (surface);
 
+  if (impl->surface_scale == scale)
+    return;
+
   impl->surface_scale = scale;
   if (impl->cairo_surface)
     cairo_surface_set_device_scale (impl->cairo_surface, impl->surface_scale, impl->surface_scale);
diff --git a/gdk/x11/gdksurface-x11.h b/gdk/x11/gdksurface-x11.h
index 0830407dd0..89f4b12845 100644
--- a/gdk/x11/gdksurface-x11.h
+++ b/gdk/x11/gdksurface-x11.h
@@ -195,7 +195,6 @@ GdkToplevelX11 *_gdk_x11_surface_get_toplevel        (GdkSurface *window);
 
 GdkCursor      *_gdk_x11_surface_get_cursor          (GdkSurface *window);
 
-void            _gdk_x11_surface_update_size         (GdkX11Surface *impl);
 void            _gdk_x11_surface_set_surface_scale   (GdkSurface *window,
                                                       int        scale);
 gboolean        _gdk_x11_surface_syncs_frames        (GdkSurface *surface);