[mutter] backends/native: Translate right coords when creating motion events

[Marge Bot <marge-bot src gnome org>]

commit 3263084bcf7f241267dc4dc840b81cc4617bed20
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Mon Mar 8 15:09:07 2021 +0100

    backends/native: Translate right coords when creating motion events
    
    With commit 7d7876880998fe7b414bb38f8094af9822020d1b we switched to
    storing pointer coordinates in MetaInputDeviceNative instead of
    ClutterInputDevice, and while we had set the coordinates of the
    ClutterInputDevice in ClutterStage when queueing an event, we now set
    the MetaInputDeviceNative coordinates in new_absolute_motion_event().
    
    Here a small mistake snuck in: new_absolute_motion_event() only
    translates the coordinates of the event, but we call
    meta_input_device_native_set_coords() using the x and y variables
    (which remain untranslated), so now the input device coordinates are no
    longer translated.
    
    Fix that by translating the coordinates of the x and y variables in case
    we're we handling a tablet/stylus event instead of only translating the
    event coordinates.
    
    Fixes https://gitlab.gnome.org/GNOME/mutter/-/issues/1685
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1760>

 src/backends/native/meta-seat-impl.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)
---
diff --git a/src/backends/native/meta-seat-impl.c b/src/backends/native/meta-seat-impl.c
index 1ffc9e6855..71da8f8fac 100644
--- a/src/backends/native/meta-seat-impl.c
+++ b/src/backends/native/meta-seat-impl.c
@@ -514,6 +514,17 @@ new_absolute_motion_event (MetaSeatImpl       *seat_impl,
                                         seat_impl->pointer_y,
                                         &x, &y);
     }
+  else
+    {
+      /* This may happen early at startup */
+      if (seat_impl->viewports)
+        {
+          meta_input_device_native_translate_coordinates_in_impl (input_device,
+                                                                  seat_impl->viewports,
+                                                                  &x,
+                                                                  &y);
+        }
+    }
 
   event->motion.time_us = time_us;
   event->motion.time = us2ms (time_us);
@@ -521,15 +532,6 @@ new_absolute_motion_event (MetaSeatImpl       *seat_impl,
   event->motion.x = x;
   event->motion.y = y;
 
-  /* This may happen early at startup */
-  if (seat_impl->viewports)
-    {
-      meta_input_device_native_translate_coordinates_in_impl (input_device,
-                                                              seat_impl->viewports,
-                                                              &event->motion.x,
-                                                              &event->motion.y);
-    }
-
   event->motion.axes = axes;
   clutter_event_set_device (event, seat_impl->core_pointer);
   clutter_event_set_source_device (event, input_device);