konva/src/GlobalObject.js

///////////////////////////////////////////////////////////////////////
//  Global Object
///////////////////////////////////////////////////////////////////////
/**
 * Kinetic Namespace
 * @namespace
 */
var Kinetic = {};
/**
 * Kinetic Global Object
 * @property {Object} GlobalObjet
 */
Kinetic.GlobalObject = {
    stages: [],
    idCounter: 0,
    isAnimating: false,
    frame: {
        time: 0,
        timeDiff: 0,
        lastTime: 0
    },
    drag: {
        moving: false,
        node: undefined,
        offset: {
            x: 0,
            y: 0
        }
    },
    extend: function(obj1, obj2) {
        for(var key in obj2.prototype) {
            if(obj2.prototype.hasOwnProperty(key) && obj1.prototype[key] === undefined) {
                obj1.prototype[key] = obj2.prototype[key];
            }
        }
    },
    _isaCanvasAnimating: function() {
        for(var n = 0; n < this.stages.length; n++) {
            if(this.stages[n].isAnimating) {
                return true;
            }
        }
        return false;
    },
    _runFrames: function() {
        for(var n = 0; n < this.stages.length; n++) {
            if(this.stages[n].isAnimating) {
                this.stages[n].onFrameFunc(this.frame);
            }
        }
    },
    _updateFrameObject: function() {
        var date = new Date();
        var time = date.getTime();
        if(this.frame.lastTime === 0) {
            this.frame.lastTime = time;
        } else {
            this.frame.timeDiff = time - this.frame.lastTime;
            this.frame.lastTime = time;
            this.frame.time += this.frame.timeDiff;
        }
    },
    _animationLoop: function() {
        if(this.isAnimating) {
            this._updateFrameObject();
            this._runFrames();
            var that = this;
            requestAnimFrame(function() {
                that._animationLoop();
            });
        }
    },
    _handleAnimation: function() {
        var that = this;
        if(!this.isAnimating && this._isaCanvasAnimating()) {
            this.isAnimating = true;
            that._animationLoop();
        } else if(this.isAnimating && !this._isaCanvasAnimating()) {
            this.isAnimating = false;
            this.frame.lastTime = 0;
        }
    }
};

window.requestAnimFrame = (function(callback) {
    return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame ||
    function(callback) {
        window.setTimeout(callback, 1000 / 60);
    };

})();