wayland: Use scale from core wl_output protocol

The “xdg-output” protocol provides clients with the outputs size and
position in compositor coordinates, and does not provide the output
scale which is already provided by the core “wl_output” protocol.

So when receiving the wl_output scale event, we should update the scale
regardless of “xdg-output” support, otherwise the scale will remain to
its default value of 1 and the surface will be scaled up by the
compositor to match the actual output scale, which causes blurry fonts
and widgets.

Fixes: https://gitlab.gnome.org/GNOME/gtk/issues/1901
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/gdk/wayland/gdkscreen-wayland.c b/gdk/wayland/gdkscreen-wayland.c
index 2457ecea2a..6aff3a5a1a 100644
--- a/gdk/wayland/gdkscreen-wayland.c
+++ b/gdk/wayland/gdkscreen-wayland.c
@@ -1591,16 +1591,18 @@ output_handle_scale (void             *data,
   GDK_NOTE (MISC,
             g_message ("handle scale output %d, scale %d", monitor->id, scale));
 
-  if (monitor_has_xdg_output (monitor))
-    return;
-
   gdk_monitor_get_geometry (GDK_MONITOR (monitor), &previous_geometry);
   previous_scale = gdk_monitor_get_scale_factor (GDK_MONITOR (monitor));
 
+  /* Set the scale from wl_output protocol, regardless of xdg-output support */
+  gdk_monitor_set_scale_factor (GDK_MONITOR (monitor), scale);
+
+  if (monitor_has_xdg_output (monitor))
+    return;
+
   width = previous_geometry.width * previous_scale;
   height = previous_geometry.height * previous_scale;
 
-  gdk_monitor_set_scale_factor (GDK_MONITOR (monitor), scale);
   monitor->width = width / scale;
   monitor->height = height / scale;