[gnome-games] display-bin: Use a slightly less hacky way to offset the game

[Alexander Mikhaylenko <alexm src gnome org>]

commit 560a880d39b27148de07d1e8e1f14a88fb41eadd
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Tue Dec 29 19:26:38 2020 +0500

    display-bin: Use a slightly less hacky way to offset the game

 src/ui/display-bin.vala  | 43 ++++++++++++++++++++-----------------------
 src/ui/display-view.ui   | 26 +++++++++++++++-----------
 src/ui/display-view.vala | 11 ++++++-----
 3 files changed, 41 insertions(+), 39 deletions(-)
---
diff --git a/src/ui/display-bin.vala b/src/ui/display-bin.vala
index e43c1d26..373d0355 100644
--- a/src/ui/display-bin.vala
+++ b/src/ui/display-bin.vala
@@ -1,38 +1,35 @@
 // This file is part of GNOME Games. License: GPL-3.0+.
 
-public class Games.DisplayBin : Gtk.Bin {
-       private int _horizontal_offset;
-       public int horizontal_offset {
-               get { return _horizontal_offset; }
+public class Games.DisplayBin : Gtk.EventBox {
+       private int _child_width;
+       public int child_width {
+               get { return _child_width; }
                set {
-                       if (horizontal_offset == value)
+                       if (child_width == value)
                                return;
 
-                       _horizontal_offset = value;
-                       queue_draw ();
+                       _child_width = value;
+                       queue_allocate ();
                }
        }
 
-       private int _vertical_offset;
-       public int vertical_offset {
-               get { return _vertical_offset; }
-               set {
-                       if (vertical_offset == value)
-                               return;
+       public override void get_preferred_width (out int minimum, out int natural) {
+               var child = get_child ();
 
-                       _vertical_offset = value;
-                       queue_draw ();
-               }
-       }
+               minimum = 0;
 
-       public override bool draw (Cairo.Context cr) {
-               if (get_direction () == Gtk.TextDirection.RTL)
-                       cr.translate (-horizontal_offset, vertical_offset);
+               if (child != null)
+                       child.get_preferred_width (null, out natural);
                else
-                       cr.translate (horizontal_offset, vertical_offset);
+                       natural = 0;
+       }
 
-               base.draw (cr);
+       public override void size_allocate (Gtk.Allocation alloc) {
+               base.size_allocate (alloc);
 
-               return true;
+               int delta = alloc.width - child_width;
+               var child = get_child ();
+               if (child != null)
+                       child.size_allocate ({ delta / 2, 0, child_width, alloc.height });
        }
 }
diff --git a/src/ui/display-view.ui b/src/ui/display-view.ui
index 7d98f8a6..344d51c9 100644
--- a/src/ui/display-view.ui
+++ b/src/ui/display-view.ui
@@ -204,26 +204,30 @@
               </object>
             </child>
             <child>
-              <object class="GtkOverlay" id="display_overlay">
+              <object class="GtkBox" id="display_box">
                 <property name="visible">True</property>
                 <child>
-                  <object class="GamesDisplayBin" id="display_bin">
+                  <object class="GtkOverlay">
                     <property name="visible">True</property>
-                    <property name="hexpand">True</property>
+                    <child>
+                      <object class="GamesDisplayBin" id="display_bin">
+                        <property name="visible">True</property>
+                        <property name="hexpand">True</property>
+                      </object>
+                    </child>
+                    <child type="overlay">
+                      <object class="GamesFlashBox" id="flash_box"/>
+                      <packing>
+                        <property name="pass-through">True</property>
+                      </packing>
+                    </child>
                   </object>
                 </child>
-                <child type="overlay">
-                  <object class="GamesFlashBox" id="flash_box"/>
-                  <packing>
-                    <property name="pass-through">True</property>
-                  </packing>
-                </child>
-                <child type="overlay">
+                <child>
                   <object class="GamesSnapshotsList" id="snapshots_list">
                     <property name="visible">True</property>
                     <property name="halign">end</property>
                     <property name="is-revealed" bind-source="GamesDisplayView" 
bind-property="is-showing-snapshots" bind-flags="bidirectional"/>
-                    <signal name="size-allocate" handler="on_snapshots_list_size_allocate"/>
                     <signal name="hidden" handler="on_snapshots_hidden"/>
                   </object>
                 </child>
diff --git a/src/ui/display-view.vala b/src/ui/display-view.vala
index a2bc5049..571e90eb 100644
--- a/src/ui/display-view.vala
+++ b/src/ui/display-view.vala
@@ -29,7 +29,7 @@ private class Games.DisplayView : Gtk.Box, UiView {
        [GtkChild]
        private Gtk.Button restart_btn;
        [GtkChild]
-       private Gtk.Overlay display_overlay;
+       private Gtk.Box display_box;
        [GtkChild]
        private DisplayBin display_bin;
        [GtkChild]
@@ -82,7 +82,7 @@ private class Games.DisplayView : Gtk.Box, UiView {
                        if (runner == null)
                                return;
 
-                       stack.visible_child = display_overlay;
+                       stack.visible_child = display_box;
 
                        var display = runner.get_display ();
                        set_display (display);
@@ -746,9 +746,10 @@ private class Games.DisplayView : Gtk.Box, UiView {
                        display_bin.remove (child);
        }
 
-       [GtkCallback]
-       private void on_snapshots_list_size_allocate (Gtk.Allocation allocation) {
-               display_bin.horizontal_offset = -allocation.width / 2;
+       protected override void size_allocate (Gtk.Allocation allocation) {
+               display_bin.child_width = allocation.width;
+
+               base.size_allocate (allocation);
        }
 
        [GtkCallback]