[gnome-shell] pointerA11yTimeout: Add a zoom out+fade animation on success

[Olivier Fourdan <ofourdan src gnome org>]

commit 5d0c403f1d0cc7c756a8578e3423826b88191b31
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Thu Aug 22 10:25:19 2019 +0200

    pointerA11yTimeout: Add a zoom out+fade animation on success
    
    We currently don't indicate success of the pie timer at all, let's do
    this by animating the circle's scale and fading it out at the same time.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/688

 js/ui/pointerA11yTimeout.js | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)
---
diff --git a/js/ui/pointerA11yTimeout.js b/js/ui/pointerA11yTimeout.js
index d285ccf2ad..ea3c2ab8bb 100644
--- a/js/ui/pointerA11yTimeout.js
+++ b/js/ui/pointerA11yTimeout.js
@@ -3,6 +3,8 @@ const { Clutter, GLib, GObject, Meta, St } = imports.gi;
 const Main = imports.ui.main;
 const Cairo = imports.cairo;
 
+const SUCCESS_ZOOM_OUT_DURATION = 150;
+
 var PieTimer = GObject.registerClass({
     Properties: {
         'angle': GObject.ParamSpec.double(
@@ -19,6 +21,8 @@ var PieTimer = GObject.registerClass({
             can_focus: false,
             reactive: false
         });
+
+        this.set_pivot_point(0.5, 0.5);
     }
 
     get angle() {
@@ -77,6 +81,8 @@ var PieTimer = GObject.registerClass({
         this.opacity = 0;
         this.x = x - this.width / 2;
         this.y = y - this.height / 2;
+        this.scale_y = 1;
+        this.scale_x = 1;
         this._angle = 0;
 
         this.show();
@@ -91,7 +97,18 @@ var PieTimer = GObject.registerClass({
         this.ease_property('angle', 2 * Math.PI, {
             duration,
             mode: Clutter.AnimationMode.LINEAR,
-            onComplete: () => this.stop()
+            onComplete: this._onTransitionComplete.bind(this)
+        });
+    }
+
+    _onTransitionComplete() {
+        this.ease({
+            scale_x: 2,
+            scale_y: 2,
+            opacity: 0,
+            duration: SUCCESS_ZOOM_OUT_DURATION,
+            mode: Clutter.AnimationMode.EASE_OUT_QUAD,
+            onStopped: () => this.hide()
         });
     }