main-window: Smooth transition to greeter screen.

 This completes a ported patch from slick-greeter. Credits to Björn Esser.

 From 5d39cade1f70ffe0a9bc38ad0b405bb55d98a505 Mon Sep 17 00:00:00 2001
 From: =?UTF-8?q?Bj=C3=B6rn=20Esser?= <besser82@fedoraproject.org>
 Date: Wed, 29 Nov 2017 18:24:15 +0100
 Subject: [PATCH] main-window: Calculate the really needed screen size properly
  (#84)

 * main-window: Calculate the really needed screen size properly

 * arctica-greeter: Smooth transition to the greeter screen

1 files changed, 19 insertions, 3 deletions

diff --git a/src/main-window.vala b/src/main-window.vala
index 5dd5a9a..cf7042e 100644
--- a/src/main-window.vala
+++ b/src/main-window.vala
@@ -36,6 +36,7 @@ public class MainWindow : Gtk.Window
     private ShutdownDialog? shutdown_dialog = null;
     private int window_size_x;
     private int window_size_y;
+    private bool do_resize;
 
     public ListStack stack;
 
@@ -158,6 +159,7 @@ public class MainWindow : Gtk.Window
         window_size_x = 0;
         window_size_y = 0;
         primary_monitor = null;
+        do_resize = false;
 
         only_on_monitor = AGSettings.get_string(AGSettings.KEY_ONLY_ON_MONITOR);
         monitor_setting_ok = only_on_monitor == "auto";
@@ -216,6 +218,14 @@ public class MainWindow : Gtk.Window
         menubar.cleanup();
     }
 
+    /* Setup the size and position of the window */
+    public void setup_window ()
+    {
+        resize (window_size_x, window_size_y);
+        move (0, 0);
+        move_to_monitor (primary_monitor);
+    }
+
     public override void realize ()
     {
         base.realize ();
@@ -275,9 +285,15 @@ public class MainWindow : Gtk.Window
         debug ("MainWindow is %dx%d pixels", window_size_x, window_size_y);
 
         background.set_monitors (monitors);
-        resize (window_size_x, window_size_y);
-        move (0, 0);
-        move_to_monitor (primary_monitor);
+
+        if(do_resize)
+        {
+            setup_window ();
+        }
+        else
+        {
+            do_resize = true;
+        }
     }
 
     /* Check if a monitor has a unique position */