Merge with revealer branch

src/PanelWindow.vala

@@ -22,14 +22,14 @@ public class Wingpanel.PanelWindow : Gtk.Window {
 
     private Widgets.Panel panel;
     private Gtk.EventControllerKey key_controller; // For keeping in memory
+    private Gtk.Revealer revealer;
     private int monitor_number;
     private int monitor_width;
     private int monitor_height;
     private int monitor_x;
     private int monitor_y;
     private int panel_height;
     private bool expanded = false;
-    private int panel_displacement;
 
     public PanelWindow (Gtk.Application application) {
         Object (
@@ -77,32 +77,28 @@ public class Wingpanel.PanelWindow : Gtk.Window {
         application.set_accels_for_action ("app.cycle", {"<Control>Tab"});
         application.set_accels_for_action ("app.cycle-back", {"<Control><Shift>Tab"});
 
-        add (panel);
+        revealer = new Gtk.Revealer () {
+            child = panel,
+            reveal_child = true,
+            transition_type = NONE
+        };
+
+        child = revealer;
 
         key_controller = new Gtk.EventControllerKey (this);
         key_controller.key_pressed.connect (on_key_pressed);
 
         panel.size_allocate.connect (update_panel_dimensions);
     }
 
-    private bool animation_step () {
-        if (panel_displacement <= panel_height * (-1)) {
-            return false;
-        }
-
-        panel_displacement--;
-
-        update_panel_dimensions ();
-
-        return true;
-    }
-
     private void on_realize () {
+        // realize isn't called when reveal_child is false, so we set true, then
+        // false, then true again to animate
+        revealer.reveal_child = false;
         update_panel_dimensions ();
-
         Services.BackgroundManager.initialize (this.monitor_number, panel_height);
-
-        Timeout.add (300 / panel_height, animation_step);
+        revealer.transition_type = SLIDE_DOWN;
+        revealer.reveal_child = true;
     }
 
     private void update_panel_dimensions () {
@@ -126,7 +122,7 @@ public class Wingpanel.PanelWindow : Gtk.Window {
         monitor_x = monitor_dimensions.x;
         monitor_y = monitor_dimensions.y;
 
-        this.move (monitor_x, monitor_y);
+        move (monitor_x, monitor_y);
 
         update_struts ();
     }