[gnome-boxes] Add Revealer actor

[Alexander Larsson <alexl src gnome org>]

commit 83067811aa85c5d97f6fe1f66162a58eb6387682
Author: Alexander Larsson <alexl redhat com>
Date:   Fri Jun 1 15:27:25 2012 +0200

    Add Revealer actor
    
    This is an actor that lets you slide in/out a child, clipping the child
    to the revealer. This is useful for instance to implement sliding in
    sidebars or notifications.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=677274

 src/Makefile.am   |    1 +
 src/revealer.vala |   88 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 89 insertions(+), 0 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index af60f51..cdeb9b0 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -51,6 +51,7 @@ gnome_boxes_SOURCES =				\
 	i-properties-provider.vala		\
 	properties.vala				\
 	remote-machine.vala			\
+	revealer.vala				\
 	selectionbar.vala			\
 	sidebar.vala				\
 	spice-display.vala			\
diff --git a/src/revealer.vala b/src/revealer.vala
new file mode 100644
index 0000000..5065acd
--- /dev/null
+++ b/src/revealer.vala
@@ -0,0 +1,88 @@
+// This file is part of GNOME Boxes. License: LGPLv2+
+using Clutter;
+
+public class Boxes.Revealer: Clutter.Actor {
+    private bool horizontal;
+    private bool revealed;
+    public uint duration;
+
+    public Revealer (bool horizontal) {
+        this.horizontal = horizontal;
+        clip_to_allocation = true;
+        revealed = true;
+        duration = 250;
+
+        if (horizontal) {
+            var layout = new Clutter.BinLayout (Clutter.BinAlignment.FILL,
+                                                Clutter.BinAlignment.FIXED);
+            this.set_layout_manager (layout);
+        } else {
+            var layout = new Clutter.BinLayout (Clutter.BinAlignment.FIXED,
+                                                Clutter.BinAlignment.FILL);
+            this.set_layout_manager (layout);
+        }
+
+        this.actor_added.connect ( (child) => {
+            if (revealed)
+                child.show ();
+            else
+                child.hide ();
+        });
+    }
+
+    public void reveal () {
+        foreach (var child in get_children ()) {
+            if (!revealed)
+                child.show ();
+            if (horizontal) {
+                if (!revealed) {
+                    float height;
+                    child.get_preferred_height (-1, null, out height);
+                    child.y = -height;
+                }
+                child.animate (Clutter.AnimationMode.EASE_IN_QUAD, duration, "y", 0f);
+            } else {
+                if (!revealed) {
+                    float width;
+                    child.get_preferred_width (-1, null, out width);
+                    child.x = -width;
+                }
+                child.animate (Clutter.AnimationMode.EASE_IN_QUAD, duration, "x", 0f);
+            }
+        }
+        revealed = true;
+    }
+
+    private void unreveal_child (Clutter.Actor child) {
+        if (horizontal) {
+            float height;
+            child.get_preferred_height (-1, null, out height);
+            var anim = child.animate (Clutter.AnimationMode.EASE_OUT_QUAD, duration, "y", -height);
+            anim.completed.connect (() => {
+                child.hide ();
+                revealed = false;
+            });
+        } else {
+            float width;
+            child.get_preferred_width (-1, null, out width);
+            var anim = child.animate (Clutter.AnimationMode.EASE_OUT_QUAD, duration, "x", -width);
+            anim.completed.connect (() => {
+                child.hide ();
+                revealed = false;
+            });
+        }
+    }
+
+    public void unreveal () {
+        if (!revealed)
+            return;
+
+        bool found_child = false;
+        foreach (var child in get_children ()) {
+            found_child = true;
+            unreveal_child (child);
+        }
+        if (!found_child)
+            revealed = false;
+    }
+}