/*
* Ticker by Grant Skinner. Dec 5, 2010
* Visit http://easeljs.com/ for documentation, updates and examples.
*
*
* Copyright (c) 2010 Grant Skinner
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
/**
* The Easel Javascript library provides a retained graphics mode for canvas
* including a full, hierarchical display list, a core interaction model, and
* helper classes to make working with Canvas much easier.
* @module EaselJS
**/
(function(window) {
// constructor:
/**
* The Ticker class uses a static interface (ex. Ticker.getPaused()) and should not be instantiated.
* Provides a centralized tick or heartbeat broadcast at a set interval. Listeners can subscribe
* to the tick event to be notified when a set time interval has elapsed.
* Note that the interval that the tick event is called is a target interval, and may be broadcast
* at a slower interval during times of high CPU load.
* @class Ticker
* @static
**/
Ticker = function() {
throw "Ticker cannot be instantiated.";
}
/**
* Event broadcast once each tick / interval. The interval is specified via the
* .setInterval(ms) or setFPS methods.
* @event tick
* @param {Number} timeElapsed The time elapsed in milliseconds since the last tick event.
*/
// private static properties:
/**
* @property _listeners
* @type Array[Object]
* @protected
**/
Ticker._listeners = [];
/**
* @property _pauseable
* @type Array[Boolean]
* @protected
**/
Ticker._pauseable = [];
/**
* @property _paused
* @type Boolean
* @protected
**/
Ticker._paused = false;
/**
* @property _inited
* @type Boolean
* @protected
**/
Ticker._inited = false;
/**
* @property _startTime
* @type Number
* @protected
**/
Ticker._startTime = 0;
/**
* @property _pausedTime
* @type Number
* @protected
**/
Ticker._pausedTime=0;
/**
* Number of ticks that have passed
* @property _ticks
* @type Number
* @protected
**/
Ticker._ticks = 0;
/**
* Number of ticks that have passed while Ticker has been paused
* @property _pausedTickers
* @type Number
* @protected
**/
Ticker._pausedTickers = 0;
/**
* @property _interval
* @type Number
* @protected
**/
Ticker._interval = 50; // READ-ONLY
/**
* @property _intervalID
* @type Number
* @protected
**/
Ticker._intervalID = null;
/**
* @property _lastTime
* @type Number
* @protected
**/
Ticker._lastTime = 0;
/**
* @property _times
* @type Array[Number]
* @protected
**/
Ticker._times = [];
// public static methods:
/**
* Adds a listener for the tick event. The listener object must expose a .tick() method,
* which will be called once each tick / interval. The interval is specified via the
* .setInterval(ms) method.
* The exposed tick method is passed a single parameter, which include the elapsed time between the
* previous tick and the current one.
* @method addListener
* @static
* @param {Object} o The object to add as a listener.
* @param {Boolean} pauseable If false, the listener will continue to have tick called
* even when Ticker is paused via Ticker.pause(). Default is true.
**/
Ticker.addListener = function(o, pauseable) {
if (!Ticker._inited) {
Ticker._inited = true;
Ticker.setInterval(Ticker._interval);
}
this.removeListener(o);
Ticker._pauseable[Ticker._listeners.length] = (pauseable == null) ? true : pauseable;
Ticker._listeners.push(o);
}
/**
* Removes the specified listener.
* @method removeListener
* @static
* @param {Object} o The object to remove from listening from the tick event.
**/
Ticker.removeListener = function(o) {
if (Ticker._listeners == null) { return; }
var index = Ticker._listeners.indexOf(o);
if (index != -1) {
Ticker._listeners.splice(index, 1);
Ticker._pauseable.splice(index, 1);
}
}
/**
* Removes all listeners.
* @method removeAllListeners
* @static
**/
Ticker.removeAllListeners = function() {
Ticker._listeners = [];
Ticker._pauseable = [];
}
/**
* Sets the target time (in milliseconds) between ticks. Default is 50 (20 FPS).
* Note actual time between ticks may be more than requested depending on CPU load.
* @method setInterval
* @static
* @param {Number} interval Time in milliseconds between ticks. Default value is 50.
**/
Ticker.setInterval = function(interval) {
if (Ticker._intervalID != null) { clearInterval(Ticker._intervalID); }
Ticker._lastTime = Ticker._getTime();
Ticker._interval = interval;
Ticker._intervalID = setInterval(Ticker._tick, interval);
}
/**
* Returns the current target time between ticks, as set with setInterval.
* @method getInterval
* @static
* @return {Number} The current target interval in milliseconds between tick events.
**/
Ticker.getInterval = function() {
return Ticker._interval;
}
/**
* Returns the target frame rate in frames per second (FPS). For example, with an
* interval of 40, getFPS() will return 25 (1000ms per second divided by 40 ms per tick = 25fps).
* @method getFPS
* @static
* @return {Number} The current target number of frames / ticks broadcast per second.
**/
Ticker.getFPS = function() {
return 1000/Ticker._interval;
}
/**
* Sets the target frame rate in frames per second (FPS). For example, with an interval of 40, getFPS() will
* return 25 (1000ms per second divided by 40 ms per tick = 25fps).
* @method setFPS
* @static
* @param {Number} value Target number of ticks broadcast per second.
**/
Ticker.setFPS = function(value) {
Ticker.setInterval(1000/value);
}
/**
* Returns the actual frames / ticks per second.
* @method getMeasuredFPS
* @static
* @param {Number} ticks Optional. The number of previous ticks over which to measure the actual
* frames / ticks per second.
* @return {Number} The actual frames / ticks per second. Depending on performance, this may differ
* from the target frames per second.
**/
Ticker.getMeasuredFPS = function(ticks) {
if (Ticker._times.length < 2) { return -1; }
// x >> 1 : use bitwise to divide by two (int math)
if (ticks == null) { ticks = Ticker.getFPS()>>1; }
ticks = Math.min(Ticker._times.length-1, ticks);
return 1000/((Ticker._times[0]-Ticker._times[ticks])/ticks);
}
/**
* While Ticker is paused, pausable listeners are not ticked. See addListener for more information.
* @method setPaused
* @static
* @param {Boolean} value Indicates whether to pause (true) or unpause (false) Ticker.
**/
Ticker.setPaused = function(value) {
Ticker._paused = value;
}
/**
* Returns a boolean indicating whether Ticker is currently paused, as set with setPaused.
* @method getPaused
* @static
* @return {Boolean} Whether the Ticker is currently paused.
**/
Ticker.getPaused = function() {
return Ticker._paused;
}
/**
* Returns the number of milliseconds that have elapsed since the first tick event listener was added to
* Ticker. For example, you could use this in a time synchronized animation to determine the exact amount of
* time that has elapsed.
* @method getTime
* @static
* @param {Boolean} pauseable Indicates whether to include time elapsed
* while Ticker was paused. If false only time elapsed while Ticker is not paused will be returned.
* If true, the value returned will be total time elapsed since the first tick event listener was added.
* @return {Number} Number of milliseconds that have elapsed since Ticker was begun.
**/
Ticker.getTime = function(pauseable) {
return Ticker._getTime() - Ticker._startTime - (pauseable ? Ticker._pausedTime : 0);
}
/**
* Returns the number of ticks that have been broadcast by Ticker.
* @method getTicks
* @static
* @param {Boolean} pauseable Indicates whether to include ticks that would have been broadcast
* while Ticker was paused. If false only tick events broadcast while Ticker is not paused will be returned.
* If true, tick events that would have been broadcast while Ticker was paused will be included in the return
* value. The default value is false.
* @return {Number} of ticks that have been broadcast.
**/
Ticker.getTicks = function(pauseable) {
return Ticker._ticks - (pauseable ?Ticker._pausedTickers : 0);
}
// private static methods:
/**
* @method _tick
* @protected
**/
Ticker._tick = function() {
Ticker._ticks++;
var time = Ticker.getTime(false);
var elapsedTime = time-Ticker._lastTime;
var paused = Ticker._paused;
if (paused) {
Ticker._pausedTickers++;
Ticker._pausedTime += elapsedTime;
}
Ticker._lastTime = time;
var pauseable = Ticker._pauseable;
var listeners = Ticker._listeners;
var l = listeners ? listeners.length : 0;
for (var i=0; i<l; i++) {
var p = pauseable[i];
var listener = listeners[i];
if (listener == null || (paused && p) || listener.tick == null) { continue; }
listener.tick(elapsedTime);
}
Ticker._times.unshift(time);
if (Ticker._times.length > 100) { Ticker._times.pop(); }
}
/**
* @method _getTime
* @protected
**/
Ticker._getTime = function() {
return new Date().getTime();
}
//docced above
Ticker._startTime = Ticker._getTime();
window.Ticker = Ticker;
}(window));