Source/Fx/Fx.js

   1 /*
   2 ---
   3
   4 name: Fx
   5
   6 description: Contains the basic animation logic to be extended by all other Fx Classes.
   7
   8 license: MIT-style license.
   9
  10 requires: [Chain, Events, Options]
  11
  12 provides: Fx
  13
  14 ...
  15 */
  16
  17 (function(){
  18
  19 var Fx = this.Fx = new Class({
  20
  21         Implements: [Chain, Events, Options],
  22
  23         options: {
  24                 /*
  25                 onStart: nil,
  26                 onCancel: nil,
  27                 onComplete: nil,
  28                 */
  29                 fps: 60,
  30                 unit: false,
  31                 duration: 500,
  32                 frames: null,
  33                 frameSkip: true,
  34                 link: 'ignore'
  35         },
  36
  37         initialize: function(options){
  38                 this.subject = this.subject || this;
  39                 this.setOptions(options);
  40         },
  41
  42         getTransition: function(){
  43                 return function(p){
  44                         return -(Math.cos(Math.PI * p) - 1) / 2;
  45                 };
  46         },
  47
  48         step: function(now){
  49                 if (this.options.frameSkip){
  50                         var diff = (this.time != null) ? (now - this.time) : 0, frames = diff / this.frameInterval;
  51                         this.time = now;
  52                         this.frame += frames;
  53                 } else {
  54                         this.frame++;
  55                 }
  56
  57                 if (this.frame < this.frames){
  58                         var delta = this.transition(this.frame / this.frames);
  59                         this.set(this.compute(this.from, this.to, delta));
  60                 } else {
  61                         this.frame = this.frames;
  62                         this.set(this.compute(this.from, this.to, 1));
  63                         this.stop();
  64                 }
  65         },
  66
  67         set: function(now){
  68                 return now;
  69         },
  70
  71         compute: function(from, to, delta){
  72                 return Fx.compute(from, to, delta);
  73         },
  74
  75         check: function(){
  76                 if (!this.isRunning()) return true;
  77                 switch (this.options.link){
  78                         case 'cancel': this.cancel(); return true;
  79                         case 'chain': this.chain(this.caller.pass(arguments, this)); return false;
  80                 }
  81                 return false;
  82         },
  83
  84         start: function(from, to){
  85                 if (!this.check(from, to)) return this;
  86                 this.from = from;
  87                 this.to = to;
  88                 this.frame = (this.options.frameSkip) ? 0 : -1;
  89                 this.time = null;
  90                 this.transition = this.getTransition();
  91                 var frames = this.options.frames, fps = this.options.fps, duration = this.options.duration;
  92                 this.duration = Fx.Durations[duration] || duration.toInt();
  93                 this.frameInterval = 1000 / fps;
  94                 this.frames = frames || Math.round(this.duration / this.frameInterval);
  95                 this.fireEvent('start', this.subject);
  96                 pushInstance.call(this, fps);
  97                 return this;
  98         },
  99
 100         stop: function(){
 101                 if (this.isRunning()){
 102                         this.time = null;
 103                         pullInstance.call(this, this.options.fps);
 104                         if (this.frames == this.frame){
 105                                 this.fireEvent('complete', this.subject);
 106                                 if (!this.callChain()) this.fireEvent('chainComplete', this.subject);
 107                         } else {
 108                                 this.fireEvent('stop', this.subject);
 109                         }
 110                 }
 111                 return this;
 112         },
 113
 114         cancel: function(){
 115                 if (this.isRunning()){
 116                         this.time = null;
 117                         pullInstance.call(this, this.options.fps);
 118                         this.frame = this.frames;
 119                         this.fireEvent('cancel', this.subject).clearChain();
 120                 }
 121                 return this;
 122         },
 123
 124         pause: function(){
 125                 if (this.isRunning()){
 126                         this.time = null;
 127                         pullInstance.call(this, this.options.fps);
 128                 }
 129                 return this;
 130         },
 131
 132         resume: function(){
 133                 if ((this.frame < this.frames) && !this.isRunning()) pushInstance.call(this, this.options.fps);
 134                 return this;
 135         },
 136
 137         isRunning: function(){
 138                 var list = instances[this.options.fps];
 139                 return list && list.contains(this);
 140         }
 141
 142 });
 143
 144 Fx.compute = function(from, to, delta){
 145         return (to - from) * delta + from;
 146 };
 147
 148 Fx.Durations = {'short': 250, 'normal': 500, 'long': 1000};
 149
 150 // global timers
 151
 152 var instances = {}, timers = {};
 153
 154 var loop = function(){
 155         var now = Date.now();
 156         for (var i = this.length; i--;){
 157                 var instance = this[i];
 158                 if (instance) instance.step(now);
 159         }
 160 };
 161
 162 var pushInstance = function(fps){
 163         var list = instances[fps] || (instances[fps] = []);
 164         list.push(this);
 165         if (!timers[fps]) timers[fps] = loop.periodical(Math.round(1000 / fps), list);
 166 };
 167
 168 var pullInstance = function(fps){
 169         var list = instances[fps];
 170         if (list){
 171                 list.erase(this);
 172                 if (!list.length && timers[fps]){
 173                         delete instances[fps];
 174                         timers[fps] = clearInterval(timers[fps]);
 175                 }
 176         }
 177 };
 178
 179 })();