[gimp] app: undeprecate gimpdisplayshell-scale.c and fix "unused variable" warning

[Michael Natterer <mitch src gnome org>]

commit d9e016bd374fb5afb4ad29b3e013d9a97c70821b
Author: Michael Natterer <mitch gimp org>
Date:   Wed May 23 23:44:19 2018 +0200

    app: undeprecate gimpdisplayshell-scale.c and fix "unused variable" warning

 app/display/gimpdisplayshell-scale.c |   13 +++++++++----
 1 files changed, 9 insertions(+), 4 deletions(-)
---
diff --git a/app/display/gimpdisplayshell-scale.c b/app/display/gimpdisplayshell-scale.c
index a9f8753..6b63bc6 100644
--- a/app/display/gimpdisplayshell-scale.c
+++ b/app/display/gimpdisplayshell-scale.c
@@ -353,7 +353,7 @@ gimp_display_shell_scale (GimpDisplayShell *shell,
 {
   GimpDisplayConfig *config;
   gdouble            current_scale;
-  gdouble            delta;
+  gdouble            delta = 0.0;
   gboolean           resize_window;
 
   g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
@@ -1206,9 +1206,14 @@ gimp_display_shell_scale_get_zoom_focus (GimpDisplayShell *shell,
         }
       else
         {
-          gtk_widget_get_pointer (shell->canvas,
-                                  &canvas_pointer_x,
-                                  &canvas_pointer_y);
+          GdkDisplay *display = gtk_widget_get_display (shell->canvas);
+          GdkSeat    *seat    = gdk_display_get_default_seat (display);
+
+          gdk_window_get_device_position (gtk_widget_get_window (shell->canvas),
+                                          gdk_seat_get_pointer (seat),
+                                          &canvas_pointer_x,
+                                          &canvas_pointer_y,
+                                          NULL);
         }
 
       if (canvas_pointer_x >= 0 &&