From 5cb02c1cb501ac396674995f5480e1f20eab04b8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20Dre=C3=9Fler?= <verdre@v0yd.nl>
Date: Wed, 21 Aug 2019 16:47:38 +0200
Subject: [PATCH] pieTimer: Use custom GObject property for animating pie

Before the move to Clutters implicit animations with 0846238f6 and
bf497ed64, we used Tweener to do a fake-animation of the opacity and
Tweeners `onUpdate` signal to queue a repaint of the PieTimer everytime
Tweener tries to update the animation.

Now, with Clutters implicit animations, there is no `onUpdate` signal
anymore and also `notify::opacity` no longer gets emitted since the
value doesn't actually change. This lead to the PieTimer no longer being
repainted, which broke the animation.

Fix this by implementing the current angle of the pie using a custom
GObject property `angle` and animating this property using the new
`actor.ease_property` method.

Fixes https://gitlab.gnome.org/GNOME/gnome-shell/issues/1533
---
 js/ui/pointerA11yTimeout.js | 41 +++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/js/ui/pointerA11yTimeout.js b/js/ui/pointerA11yTimeout.js
index 77b17ac37..970ca6b33 100644
--- a/js/ui/pointerA11yTimeout.js
+++ b/js/ui/pointerA11yTimeout.js
@@ -3,21 +3,37 @@ const { Clutter, GLib, GObject, Meta, St } = imports.gi;
 const Main = imports.ui.main;
 const Cairo = imports.cairo;
 
-var PieTimer = GObject.registerClass(
-class PieTimer extends St.DrawingArea {
+var PieTimer = GObject.registerClass({
+    Properties: {
+        'angle': GObject.ParamSpec.double(
+            'angle', 'angle', 'angle',
+            GObject.ParamFlags.READWRITE,
+            0, 2 * Math.PI, 0)
+    }
+}, class PieTimer extends St.DrawingArea {
     _init() {
         this._x = 0;
         this._y = 0;
-        this._startTime = 0;
-        this._duration = 0;
+        this._angle = 0;
         super._init({
             style_class: 'pie-timer',
             visible: false,
             can_focus: false,
             reactive: false
         });
+    }
 
-        this.connect('notify::opacity', this.queue_repaint.bind(this));
+    get angle() {
+        return this._angle;
+    }
+
+    set angle(angle) {
+        if (this._angle == angle)
+            return;
+
+        this._angle = angle;
+        this.notify('angle');
+        this.queue_repaint();
     }
 
     vfunc_repaint() {
@@ -28,11 +44,8 @@ class PieTimer extends St.DrawingArea {
         let [width, height] = this.get_surface_size();
         let radius = Math.min(width / 2, height / 2);
 
-        let currentTime = GLib.get_monotonic_time() / 1000.0;
-        let ellapsed = currentTime - this._startTime;
-        let angle = (ellapsed / this._duration) * 2 * Math.PI;
         let startAngle = 3 * Math.PI / 2;
-        let endAngle = startAngle + angle;
+        let endAngle = startAngle + this._angle;
 
         let cr = this.get_context();
         cr.setLineCap(Cairo.LineCap.ROUND);
@@ -60,16 +73,14 @@ class PieTimer extends St.DrawingArea {
 
         this.x = x - this.width / 2;
         this.y = y - this.height / 2;
+        this._angle = 0;
+
         this.show();
         Main.uiGroup.set_child_above_sibling(this, null);
 
-        this._startTime = GLib.get_monotonic_time() / 1000.0;
-        this._duration = duration;
-
-        this.ease({
-            opacity: 255,
+        this.ease_property('angle', 2 * Math.PI, {
             duration,
-            mode: Clutter.AnimationMode.EASE_OUT_QUAD,
+            mode: Clutter.AnimationMode.LINEAR,
             onComplete: () => this.stop()
         });
     }