// Copyright © 2007. Adobe Systems Incorporated. All Rights Reserved.
package fl.transitions.easing
{

/**
 * The None class defines easing functions to implement 
 * nonaccelerated motion with ActionScript animations. 
 * Its methods all produce the same effect, a constant motion.
 * The various names, <code>easeIn</code>, <code>easeOut</code> and so on
 * are provided in the interest of polymorphism.
 * The None class is identical to the fl.motion.easing.Linear class in functionality.
 * 
 * @playerversion Flash 9.0
 * @langversion 3.0
 * @keyword Ease, Transition    
 * @see fl.transitions.TransitionManager  
 */  
public class None
{


	//--------------------------------------------------------------------------
	//
	//  Class methods
	//
	//--------------------------------------------------------------------------
	
    /**
     * The <code>easeNone()</code> method defines a constant motion, 
     * with no acceleration. 
     *
     * @param t Specifies the current time, between 0 and duration inclusive.
     *
     * @param b Specifies the initial value of the animation property.
     *
     * @param c Specifies the total change in the animation property.
     *
     * @param d Specifies the duration of the motion.
     *
     * @return The value of the interpolated property at the specified time.
     *
     * @playerversion Flash 9.0
     * @langversion 3.0
     * @keyword Ease, Transition    
     * @see fl.transitions.TransitionManager          
     */  
	public static function easeNone(t:Number, b:Number,
									c:Number, d:Number):Number
	{
		return c * t / d + b;
	}

    /**
     * The <code>easeIn()</code> method defines a constant motion, 
     * with no acceleration. 
     *
     * @param t Specifies the current time, between 0 and duration inclusive.
     *
     * @param b Specifies the initial value of the animation property.
     *
     * @param c Specifies the total change in the animation property.
     *
     * @param d Specifies the duration of the motion.
     *
     * @return The value of the interpolated property at the specified time.
     *
     * @includeExample examples/None.easeIn.1.as -noswf
     *
     * @playerversion Flash 9.0
     * @langversion 3.0
     * @keyword Ease, Transition    
     * @see fl.transitions.TransitionManager          
     */  
	public static function easeIn(t:Number, b:Number,
								  c:Number, d:Number):Number
	{
		return c * t / d + b;
	}

    /**
     * The <code>easeOut()</code> method defines a constant motion, 
     * with no acceleration. 
     *
     * @param t Specifies the current time, between 0 and duration inclusive.
     *
     * @param b Specifies the initial value of the animation property.
     *
     * @param c Specifies the total change in the animation property.
     *
     * @param d Specifies the duration of the motion.
     *
     * @return The value of the interpolated property at the specified time.
     *
     * @includeExample examples/None.easeOut.1.as -noswf
     *
     * @playerversion Flash 9.0
     * @langversion 3.0
     * @keyword Ease, Transition    
     * @see fl.transitions.TransitionManager          
     */  
	public static function easeOut(t:Number, b:Number,
								   c:Number, d:Number):Number
	{
		return c * t / d + b;
	}

    /**
     * The <code>easeInOut()</code> method defines a constant motion, 
     * with no acceleration. 
     *
     * @param t Specifies the current time, between 0 and duration inclusive.
     *
     * @param b Specifies the initial value of the animation property.
     *
     * @param c Specifies the total change in the animation property.
     *
     * @param d Specifies the duration of the motion.
     *
     * @return The value of the interpolated property at the specified time.
     *
     * @includeExample examples/None.easeInOut.1.as -noswf
     *
     * @playerversion Flash 9.0
     * @langversion 3.0
     * @keyword Ease, Transition    
     * @see fl.transitions.TransitionManager          
     */  
	public static function easeInOut(t:Number, b:Number,
									 c:Number, d:Number):Number
	{
		return c * t / d + b;
	}
}

}
