dojo.provide("dojox.fx._core");

dojox.fx._Line = function(start, end){
	// summary: a custom _Line to accomodate multi-dimensional values
	//	
	// description: 
	//	a normal dojo._Line is the curve, and does Line(start,end)
	//	for propertyAnimation. as we make more complicatied animations, we realize
	//	some properties can have 2, or 4 values relevant (x,y) or (t,l,r,b) for example 
	//
	// 	this function provides support for those Lines, and is ported directly from 0.4
	//	this is a lot of extra code for something so seldom used, so we'll put it here as
	//	and optional core addition. you can create a new line, and use it during onAnimate
	//	as you see fit.
	//
	// start: Integer|Array
	//	An Integer (or an Array of integers) to use as a starting point
	// end: Integer|Array
	//	An Integer (or an Array of integers) to use as an ending point
	//
	// example: see dojox.fx.smoothScroll 
	//
	// example: 
	// |	// this is 10 .. 100 and 50 .. 500
	// |	var curve = new dojox.fx._Line([10,50],[100,500]);
	// |	// dojo._Animation.onAnimate is called at every step of the animation
	// |	// to define current values. this _Line returns an array
	// | 	// at each step. arguments[0] and [1] in this example. 
	//
	this.start = start;
	this.end = end;
	
	var isArray = dojo.isArray(start), 
		d = (isArray ? [] : end - start);
	
	if(isArray){
		// multi-dimensional branch
		dojo.forEach(this.start, function(s, i){
			d[i] = this.end[i] - s;
		}, this);
		
		this.getValue = function(/*float*/ n){
			var res = [];
			dojo.forEach(this.start, function(s, i){
				res[i] = (d[i] * n) + s;
			}, this);
			return res; // Array
		}
	}else{
		// single value branch, document here for both branches:
		this.getValue = function(/*float*/ n){
			// summary: Returns the point on the line, or an array of points
			// n: a floating point number greater than 0 and less than 1
			// returns: Mixed 
			return (d * n) + this.start; // Decimal
		}
	}
};
