[gnome-initial-setup] Handle screen resolution changes

[Matthias Clasen <matthiasc src gnome org>]

commit b20422961a6b34d74782108249e9822adcc2df38
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Feb 11 15:37:29 2016 -0500

    Handle screen resolution changes
    
    When running in VMs, it is not uncommon to see resolution changes
    at runtime. Handle this, and update all the things that we adjust
    for small screens, like scrollbars, image visibility, window
    placement and sizing.
    
    To do so, add a GisDriver::small-screen property and have GisPage
    listen to changes of this property.

 gnome-initial-setup/gis-driver.c |  161 +++++++++++++++++++++++++++++---------
 gnome-initial-setup/gis-page.c   |   15 ++++-
 2 files changed, 137 insertions(+), 39 deletions(-)
---
diff --git a/gnome-initial-setup/gis-driver.c b/gnome-initial-setup/gis-driver.c
index 7eb9c9a..aecec2d 100644
--- a/gnome-initial-setup/gis-driver.c
+++ b/gnome-initial-setup/gis-driver.c
@@ -59,6 +59,7 @@ enum {
   PROP_0,
   PROP_MODE,
   PROP_USERNAME,
+  PROP_SMALL_SCREEN,
   PROP_LAST,
 };
 
@@ -76,6 +77,7 @@ struct _GisDriverPrivate {
 
   GisDriverMode mode;
   UmAccountMode account_mode;
+  gboolean small_screen;
 };
 typedef struct _GisDriverPrivate GisDriverPrivate;
 
@@ -100,35 +102,15 @@ static void
 prepare_main_window (GisDriver *driver)
 {
   GisDriverPrivate *priv = gis_driver_get_instance_private (driver);
-  GdkGeometry size_hints;
-
-  if (gis_driver_is_small_screen (driver))
-    {
-      GtkWidget *child, *sw;
-
-      child = g_object_ref (gtk_bin_get_child (GTK_BIN (priv->main_window)));
-      gtk_container_remove (GTK_CONTAINER (priv->main_window), child);
-      sw = gtk_scrolled_window_new (NULL, NULL);
-      gtk_widget_show (sw);
-      gtk_container_add (GTK_CONTAINER (priv->main_window), sw);
-      gtk_container_add (GTK_CONTAINER (sw), child);
-      g_object_unref (child);
-
-      gtk_window_maximize (priv->main_window);
-    }
-  else
-    {
-      size_hints.min_width = 1024;
-      size_hints.min_height = 768;
-      size_hints.win_gravity = GDK_GRAVITY_CENTER;
+  GtkWidget *child, *sw;
 
-      gtk_window_set_geometry_hints (priv->main_window,
-                                     NULL,
-                                     &size_hints,
-                                     GDK_HINT_MIN_SIZE | GDK_HINT_WIN_GRAVITY);
-      gtk_window_set_resizable (priv->main_window, FALSE);
-      gtk_window_set_position (priv->main_window, GTK_WIN_POS_CENTER_ALWAYS);
-    }
+  child = g_object_ref (gtk_bin_get_child (GTK_BIN (priv->main_window)));
+  gtk_container_remove (GTK_CONTAINER (priv->main_window), child);
+  sw = gtk_scrolled_window_new (NULL, NULL);
+  gtk_widget_show (sw);
+  gtk_container_add (GTK_CONTAINER (priv->main_window), sw);
+  gtk_container_add (GTK_CONTAINER (sw), child);
+  g_object_unref (child);
 
   gtk_window_set_titlebar (priv->main_window,
                            gis_assistant_get_titlebar (priv->assistant));
@@ -252,10 +234,13 @@ gis_driver_get_mode (GisDriver *driver)
 gboolean
 gis_driver_is_small_screen (GisDriver *driver)
 {
-  GdkScreen *screen;
-
-  screen = gdk_screen_get_default ();
+  GisDriverPrivate *priv = gis_driver_get_instance_private (driver);
+  return priv->small_screen;
+}
 
+static gboolean
+screen_is_small (GdkScreen *screen)
+{
   if (g_getenv ("GIS_SMALL_SCREEN"))
     return TRUE;
 
@@ -278,6 +263,9 @@ gis_driver_get_property (GObject      *object,
     case PROP_USERNAME:
       g_value_set_string (value, priv->username);
       break;
+    case PROP_SMALL_SCREEN:
+      g_value_set_boolean (value, priv->small_screen);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -318,21 +306,104 @@ gis_driver_activate (GApplication *app)
   gtk_window_present (GTK_WINDOW (priv->main_window));
 }
 
+static gboolean
+maximize (gpointer data)
+{
+  GtkWindow *window = data;
+
+  gtk_window_maximize (window);
+  gtk_window_present (window);
+
+  return G_SOURCE_REMOVE;
+}
+
+static gboolean
+unmaximize (gpointer data)
+{
+  GtkWindow *window = data;
+
+  gtk_window_unmaximize (window);
+  gtk_window_present (window);
+
+  return G_SOURCE_REMOVE;
+}
+
 static void
-window_realize_cb (GtkWidget *widget, gpointer user_data)
+update_screen_size (GisDriver *driver)
 {
-  GisDriver *driver = GIS_DRIVER (user_data);
   GisDriverPrivate *priv = gis_driver_get_instance_private (driver);
   GdkWindow *window;
-  GdkWMFunction funcs;
+  GdkGeometry size_hints;
+  GtkWidget *sw;
+
+  if (!gtk_widget_get_realized (GTK_WIDGET (priv->main_window)))
+    return;
 
+  sw = gtk_bin_get_child (GTK_BIN (priv->main_window));
   window = gtk_widget_get_window (GTK_WIDGET (priv->main_window));
-  funcs = GDK_FUNC_ALL | GDK_FUNC_MINIMIZE | GDK_FUNC_CLOSE;
 
-  if (!gis_driver_is_small_screen (driver))
-    funcs |= GDK_FUNC_RESIZE | GDK_FUNC_MOVE | GDK_FUNC_MAXIMIZE;
+  if (priv->small_screen)
+    {
+      if (window)
+        gdk_window_set_functions (window,
+                                  GDK_FUNC_ALL | GDK_FUNC_MINIMIZE | GDK_FUNC_CLOSE);
+
+      gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
+                                      GTK_POLICY_AUTOMATIC,
+                                      GTK_POLICY_AUTOMATIC);
 
-  gdk_window_set_functions (window, funcs);
+      gtk_window_set_geometry_hints (priv->main_window, NULL, NULL, 0);
+      gtk_window_set_resizable (priv->main_window, TRUE);
+      gtk_window_set_position (priv->main_window, GTK_WIN_POS_NONE);
+
+      g_idle_add (maximize, priv->main_window);
+    }
+  else
+    {
+      if (window)
+        gdk_window_set_functions (window,
+                                  GDK_FUNC_ALL | GDK_FUNC_MINIMIZE | GDK_FUNC_CLOSE |
+                                  GDK_FUNC_RESIZE | GDK_FUNC_MOVE | GDK_FUNC_MAXIMIZE);
+
+      gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
+                                      GTK_POLICY_NEVER,
+                                      GTK_POLICY_NEVER);
+
+      size_hints.min_width = 1024;
+      size_hints.min_height = 768;
+      size_hints.win_gravity = GDK_GRAVITY_CENTER;
+
+      gtk_window_set_geometry_hints (priv->main_window,
+                                     NULL,
+                                     &size_hints,
+                                     GDK_HINT_MIN_SIZE | GDK_HINT_WIN_GRAVITY);
+      gtk_window_set_resizable (priv->main_window, FALSE);
+      gtk_window_set_position (priv->main_window, GTK_WIN_POS_CENTER_ALWAYS);
+
+      g_idle_add (unmaximize, priv->main_window);
+    }
+}
+
+static void
+screen_size_changed (GdkScreen *screen, GisDriver *driver)
+{
+  GisDriverPrivate *priv = gis_driver_get_instance_private (driver);
+  gboolean small_screen;
+
+  small_screen = screen_is_small (screen);
+
+  if (priv->small_screen != small_screen)
+    {
+      priv->small_screen = small_screen;
+      update_screen_size (driver);
+      g_object_notify (G_OBJECT (driver), "small-screen");
+    }
+}
+
+static void
+window_realize_cb (GtkWidget *widget, gpointer user_data)
+{
+  update_screen_size (GIS_DRIVER (user_data));
 }
 
 static void
@@ -369,6 +440,15 @@ gis_driver_startup (GApplication *app)
 static void
 gis_driver_init (GisDriver *driver)
 {
+  GisDriverPrivate *priv = gis_driver_get_instance_private (driver);
+  GdkScreen *screen;
+
+  screen = gdk_screen_get_default ();
+
+  priv->small_screen = screen_is_small (screen);
+
+  g_signal_connect (screen, "size-changed",
+                    G_CALLBACK (screen_size_changed), driver);
 }
 
 static void
@@ -411,6 +491,11 @@ gis_driver_class_init (GisDriverClass *klass)
                          NULL,
                          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
 
+  obj_props[PROP_SMALL_SCREEN] =
+    g_param_spec_boolean ("small-screen", "", "",
+                          FALSE,
+                          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);
+
   g_object_class_install_properties (gobject_class, PROP_LAST, obj_props);
 }
 
diff --git a/gnome-initial-setup/gis-page.c b/gnome-initial-setup/gis-page.c
index 3365230..9427f71 100644
--- a/gnome-initial-setup/gis-page.c
+++ b/gnome-initial-setup/gis-page.c
@@ -87,7 +87,10 @@ gis_page_get_property (GObject    *object,
       g_value_set_boolean (value, gis_page_get_applying (page));
       break;
     case PROP_SMALL_SCREEN:
-      g_value_set_boolean (value, gis_driver_is_small_screen (page->driver));
+      if (page->driver)
+        g_object_get_property (G_OBJECT (page->driver), "small-screen", value);
+      else
+        g_value_set_boolean (value, FALSE);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -96,6 +99,12 @@ gis_page_get_property (GObject    *object,
 }
 
 static void
+small_screen_changed (GObject *driver, GParamSpec *pspec, GisPage *page)
+{
+  g_object_notify_by_pspec (G_OBJECT (page), obj_props[PROP_SMALL_SCREEN]);
+}
+
+static void
 gis_page_set_property (GObject      *object,
                        guint         prop_id,
                        const GValue *value,
@@ -107,6 +116,8 @@ gis_page_set_property (GObject      *object,
     {
     case PROP_DRIVER:
       page->driver = g_value_dup_object (value);
+      g_signal_connect (page->driver, "notify::small-screen",
+                        G_CALLBACK (small_screen_changed), page);
       break;
     case PROP_TITLE:
       gis_page_set_title (page, (char *) g_value_get_string (value));
@@ -149,6 +160,8 @@ gis_page_dispose (GObject *object)
   if (priv->apply_cancel)
     g_cancellable_cancel (priv->apply_cancel);
 
+  if (page->driver)
+    g_signal_handlers_disconnect_by_func (page->driver, small_screen_changed, page);
   g_clear_object (&page->driver);
 
   G_OBJECT_CLASS (gis_page_parent_class)->dispose (object);