[gnome-taquin] Add unfullscreen button.

[Arnaud B. <arnaudb src gnome org>]

commit d29909cef17af48249328c358947fb8c64864203
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Thu Feb 21 17:26:48 2019 +0100

    Add unfullscreen button.

 data/base-window.ui        | 29 +++++++++++++++++++++++++++--
 data/taquin.css            |  4 ++++
 src/adaptative-window.vala |  7 +++++++
 src/base-window.vala       | 15 ++++++++++++++-
 4 files changed, 52 insertions(+), 3 deletions(-)
---
diff --git a/data/base-window.ui b/data/base-window.ui
index 22e39e3..87931be 100644
--- a/data/base-window.ui
+++ b/data/base-window.ui
@@ -21,9 +21,34 @@
     <property name="visible">False</property>
     <signal name="key-press-event" handler="on_key_press_event"/>
     <child>
-      <object class="GtkGrid" id="main_grid">
+      <object class="GtkOverlay">
         <property name="visible">True</property>
-        <property name="orientation">vertical</property>
+        <child>
+          <object class="GtkGrid" id="main_grid">
+            <property name="visible">True</property>
+            <property name="orientation">vertical</property>
+          </object>
+        </child>
+        <child type="overlay">
+          <object class="GtkButton" id="unfullscreen_button">
+            <property name="visible">False</property>
+            <property name="halign">end</property>
+            <property name="valign">start</property>
+            <property name="action-name">base.unfullscreen</property>
+            <style>
+              <class name="image-button"/>
+              <class name="unfullscreen-button"/>
+              <class name="flat"/>
+            </style>
+            <child>
+              <object class="GtkImage">
+                <property name="icon-name">view-restore-symbolic</property>
+                <property name="visible">True</property>
+                <property name="icon-size">1</property>
+              </object>
+            </child>
+          </object>
+        </child>
       </object>
     </child>
   </template>
diff --git a/data/taquin.css b/data/taquin.css
index daecc7e..4a0482b 100644
--- a/data/taquin.css
+++ b/data/taquin.css
@@ -17,6 +17,10 @@
 
 @import url("base-window.css");
 
+button.unfullscreen-button {
+  margin:6px;
+}
+
 /* hack: fix the double spacing around the centerwidget box, on extra-thin window (visible with big moves 
count) */
 .extra-thin-window.thin-window button.new-game-button { margin-right:-6px; }
 
diff --git a/src/adaptative-window.vala b/src/adaptative-window.vala
index 3f85b65..e182c5f 100644
--- a/src/adaptative-window.vala
+++ b/src/adaptative-window.vala
@@ -229,8 +229,13 @@ private abstract class AdaptativeWindow : ApplicationWindow
             window_is_maximized = (event.new_window_state & Gdk.WindowState.MAXIMIZED) != 0;
 
         /* fullscreen: saved as maximized */
+        bool window_was_fullscreen = window_is_fullscreen;
         if ((event.changed_mask & Gdk.WindowState.FULLSCREEN) != 0)
             window_is_fullscreen = (event.new_window_state & Gdk.WindowState.FULLSCREEN) != 0;
+        if (window_was_fullscreen && !window_is_fullscreen)
+            on_unfullscreen ();
+        else if (!window_was_fullscreen && window_is_fullscreen)
+            on_fullscreen ();
 
         /* tiled: not saved, but should not change saved window size */
         Gdk.WindowState tiled_state = Gdk.WindowState.TILED
@@ -243,6 +248,8 @@ private abstract class AdaptativeWindow : ApplicationWindow
 
         return false;
     }
+    protected abstract void on_fullscreen ();
+    protected abstract void on_unfullscreen ();
 
     [GtkCallback]
     private void on_size_allocate (Allocation allocation)
diff --git a/src/base-window.vala b/src/base-window.vala
index 52b0613..3d69ec5 100644
--- a/src/base-window.vala
+++ b/src/base-window.vala
@@ -73,12 +73,23 @@ private class BaseWindow : AdaptativeWindow, AdaptativeWidget
     \*/
 
     [GtkChild] private Grid main_grid;
+    [GtkChild] private Button unfullscreen_button;
 
     protected void add_to_main_grid (Widget widget)
     {
         main_grid.add (widget);
     }
 
+    protected override void on_fullscreen ()
+    {
+        unfullscreen_button.show ();
+    }
+
+    protected override void on_unfullscreen ()
+    {
+        unfullscreen_button.hide ();
+    }
+
     /*\
     * * action entries
     \*/
@@ -105,7 +116,9 @@ private class BaseWindow : AdaptativeWindow, AdaptativeWidget
         { "show-default-view",  show_default_view   },
 
         { "help",               help                },
-        { "about",              about               }
+        { "about",              about               },
+
+        { "unfullscreen",       unfullscreen        }
     };
 
     /*\