[gnome-nibbles/arnaudb/wip/gtk4: 142/188] Handle window state change.

[Arnaud B. <arnaudb src gnome org>]

commit 495e6b44f9e9e06b6d6607894c3af51320863c2e
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Wed Sep 30 16:23:34 2020 +0200

    Handle window state change.

 src/nibbles-window.vala | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)
---
diff --git a/src/nibbles-window.vala b/src/nibbles-window.vala
index 6961326..85d48c8 100644
--- a/src/nibbles-window.vala
+++ b/src/nibbles-window.vala
@@ -126,7 +126,7 @@ private class NibblesWindow : ApplicationWindow
         }
 
         size_allocate.connect (size_allocate_cb);
-        window_state_event.connect (window_state_event_cb);
+        map.connect (init_state_watcher);
         set_default_size (settings.get_int ("window-width"), settings.get_int ("window-height"));
         if (settings.get_boolean ("window-is-maximized"))
             maximize ();
@@ -267,6 +267,34 @@ private class NibblesWindow : ApplicationWindow
         return Source.CONTINUE;
     }
 
+    /*\
+    * * State saving
+    \*/
+
+    private inline void init_state_watcher ()
+    {
+        Gdk.Surface? nullable_surface = window.get_surface ();  // TODO report bug, get_surface() returns a 
nullable Surface
+        if (nullable_surface == null || !((!) nullable_surface is Gdk.Toplevel))
+            assert_not_reached ();
+        surface = (Gdk.Toplevel) (!) nullable_surface;
+        surface.notify ["state"].connect (on_state_changed);
+    }
+
+    private Gdk.Toplevel surface;
+    private const Gdk.ToplevelState tiled_state = Gdk.ToplevelState.TILED
+                                                | Gdk.ToplevelState.TOP_TILED
+                                                | Gdk.ToplevelState.BOTTOM_TILED
+                                                | Gdk.ToplevelState.LEFT_TILED
+                                                | Gdk.ToplevelState.RIGHT_TILED;
+    private inline void on_state_changed ()
+    {
+        Gdk.ToplevelState state = surface.get_state ();
+
+        window_is_maximized  = (state & Gdk.ToplevelState.MAXIMIZED)  != 0;
+        /* tiled: not saved, but should not change saved window size */
+        window_is_tiled      = (state & tiled_state)                  != 0;
+    }
+
     /*\
     * * Window events
     \*/
@@ -294,16 +322,6 @@ private class NibblesWindow : ApplicationWindow
         get_size (out window_width, out window_height);
     }
 
-    private bool window_state_event_cb (Gdk.EventWindowState event)
-    {
-        if ((event.changed_mask & Gdk.WindowState.MAXIMIZED) != 0)
-            window_is_maximized = (event.new_window_state & Gdk.WindowState.MAXIMIZED) != 0;
-        /* We don’t save this state, but track it for saving size allocation */
-        if ((event.changed_mask & Gdk.WindowState.TILED) != 0)
-            window_is_tiled = (event.new_window_state & Gdk.WindowState.TILED) != 0;
-        return false;
-    }
-
     private void start_game ()
     {
         settings.set_boolean ("first-run", false);