third_party/web-animations-js/sources/src/tick.js

   1 // Copyright 2014 Google Inc. All rights reserved.
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 //     You may obtain a copy of the License at
   6 //
   7 // http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 //     See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15
  16 (function(shared, scope, testing) {
  17   var originalRequestAnimationFrame = window.requestAnimationFrame;
  18   var rafCallbacks = [];
  19   var rafId = 0;
  20   window.requestAnimationFrame = function(f) {
  21     var id = rafId++;
  22     if (rafCallbacks.length == 0 && !WEB_ANIMATIONS_TESTING) {
  23       originalRequestAnimationFrame(processRafCallbacks);
  24     }
  25     rafCallbacks.push([id, f]);
  26     return id;
  27   };
  28
  29   window.cancelAnimationFrame = function(id) {
  30     rafCallbacks.forEach(function(entry) {
  31       if (entry[0] == id) {
  32         entry[1] = function() {};
  33       }
  34     });
  35   };
  36
  37   function processRafCallbacks(t) {
  38     var processing = rafCallbacks;
  39     rafCallbacks = [];
  40     tick(t);
  41     processing.forEach(function(entry) { entry[1](t); });
  42     if (needsRetick)
  43       tick(t);
  44     applyPendingEffects();
  45   }
  46
  47   function comparePlayers(leftPlayer, rightPlayer) {
  48     return leftPlayer._sequenceNumber - rightPlayer._sequenceNumber;
  49   }
  50
  51   function InternalTimeline() {
  52     this._players = [];
  53     // Android 4.3 browser has window.performance, but not window.performance.now
  54     this.currentTime = window.performance && performance.now ? performance.now() : 0;
  55   };
  56
  57   InternalTimeline.prototype = {
  58     _play: function(source) {
  59       source._timing = shared.normalizeTimingInput(source.timing);
  60       var player = new scope.Player(source);
  61       player._idle = false;
  62       player._timeline = this;
  63       this._players.push(player);
  64       scope.restart();
  65       scope.invalidateEffects();
  66       return player;
  67     }
  68   };
  69
  70   var ticking = false;
  71   var hasRestartedThisFrame = false;
  72
  73   scope.restart = function() {
  74     if (!ticking) {
  75       ticking = true;
  76       requestAnimationFrame(function() {});
  77       hasRestartedThisFrame = true;
  78     }
  79     return hasRestartedThisFrame;
  80   };
  81
  82   var needsRetick = false;
  83   scope.invalidateEffects = function() {
  84     needsRetick = true;
  85   };
  86
  87   var pendingEffects = [];
  88   function applyPendingEffects() {
  89     pendingEffects.forEach(function(f) { f(); });
  90   }
  91
  92   var originalGetComputedStyle = window.getComputedStyle;
  93   Object.defineProperty(window, 'getComputedStyle', {
  94     configurable: true,
  95     enumerable: true,
  96     value: function() {
  97       if (needsRetick) tick(timeline.currentTime);
  98       applyPendingEffects();
  99       return originalGetComputedStyle.apply(this, arguments);
 100     },
 101   });
 102
 103   function tick(t) {
 104     hasRestartedThisFrame = false;
 105     var timeline = scope.timeline;
 106     timeline.currentTime = t;
 107     timeline._players.sort(comparePlayers);
 108     ticking = false;
 109     var updatingPlayers = timeline._players;
 110     timeline._players = [];
 111
 112     var newPendingClears = [];
 113     var newPendingEffects = [];
 114     updatingPlayers = updatingPlayers.filter(function(player) {
 115       player._inTimeline = player._tick(t);
 116
 117       if (!player._inEffect)
 118         newPendingClears.push(player._source);
 119       else
 120         newPendingEffects.push(player._source);
 121
 122       if (!player.finished && !player.paused && !player._idle)
 123         ticking = true;
 124
 125       return player._inTimeline;
 126     });
 127
 128     pendingEffects.length = 0;
 129     pendingEffects.push.apply(pendingEffects, newPendingClears);
 130     pendingEffects.push.apply(pendingEffects, newPendingEffects);
 131
 132     timeline._players.push.apply(timeline._players, updatingPlayers);
 133     needsRetick = false;
 134
 135     if (ticking)
 136       requestAnimationFrame(function() {});
 137   };
 138
 139   if (WEB_ANIMATIONS_TESTING) {
 140     testing.tick = processRafCallbacks;
 141     testing.isTicking = function() { return ticking; };
 142     testing.setTicking = function(newVal) { ticking = newVal; };
 143   }
 144
 145   var timeline = new InternalTimeline();
 146   scope.timeline = timeline;
 147
 148 })(webAnimationsShared, webAnimations1, webAnimationsTesting);