add extjs 6.0.1 sources

[extjs.git] / extjs / packages / core / src / fx / easing / Momentum.js

/**\r
 * @private\r
 */\r
Ext.define('Ext.fx.easing.Momentum', {\r
\r
    extend: 'Ext.fx.easing.Abstract',\r
\r
    config: {\r
        acceleration: 30,\r
        friction: 0,\r
        startVelocity: 0\r
    },\r
\r
    alpha: 0,\r
\r
    updateFriction: function(friction) {\r
        var theta = Math.log(1 - (friction / 10));\r
\r
        this.theta = theta;\r
\r
        this.alpha = theta / this.getAcceleration();\r
    },\r
\r
    updateStartVelocity: function(velocity) {\r
        this.velocity = velocity * this.getAcceleration();\r
    },\r
\r
    updateAcceleration: function(acceleration) {\r
        this.velocity = this.getStartVelocity() * acceleration;\r
\r
        this.alpha = this.theta / acceleration;\r
    },\r
\r
    getValue: function() {\r
        return this.getStartValue() - this.velocity * (1 - this.getFrictionFactor()) / this.theta;\r
    },\r
\r
    getFrictionFactor: function() {\r
        var deltaTime = Ext.Date.now() - this.getStartTime();\r
\r
        return Math.exp(deltaTime * this.alpha);\r
    },\r
\r
    getVelocity: function() {\r
        return this.getFrictionFactor() * this.velocity;\r
    }\r
});\r