/* 

		dw_slide.js 

		requires dw_core.js

		version date: July 2002



		This code is from Dynamic Web Coding - www.dyn-web.com 

    See Terms of Use at http://www.dyn-web.com/bus/terms.html

    Permission granted to use this code 

    as long as this entire notice is included.

		

		This code was developed while studying code from: 

		dynduo by Dan Steinman at www.dansteinman.com/dynduo,

		www.cross-browser.com by Mike Foster,

		and www.youngpup.net by Aaron Boodman.

		Code is adapted from those sources.

		

		The slide methods are modified from cbe_slide.js from

		www.cross-browser.com by Mike Foster, where the following

		notice is included:

		

		* Copyright (c) 2002 Michael Foster (mike@cross-browser.com)

 		* This library is distributed under the terms of the 

		* GNU Lesser General Public License (gnu.org).

	  * Time-based, parametric equation animation derived from 

	  * algorithms by Aaron Boodman (youngpup.net), 

	  * and Sebastien Chevrel (sebchevrel.com).

		

    Permission granted to use this code 

    as long as this entire notice is included.

*/





// slide methods

// heavily borrowed from www.cross-browser.com

dynObj.prototype.slideTo = function(destX,destY,slideTime,fn,container) {

	this.slideTime = slideTime||.0001; this.fn=fn||null;

	// ok to slide along one axis only

	if (destX==null) destX=this.x;

	if (destY==null) destY=this.y;

	if (isNaN(parseInt(destX))) {	// if relative to container (string)

		this.posRel(destX,destY,container);

		this.destX=this.leftPos; this.destY=this.topPos;

	} else {

		this.destX=destX; this.destY=destY;

	}

	this.distX=this.destX-this.x; this.startX=this.x;

	this.distY=this.destY-this.y; this.startY=this.y;

	this.slideStart = (new Date()).getTime();

	if (this.slideProp=="steady") this.per = 1/this.slideTime;

	else this.per = Math.PI/(2*this.slideTime);

	if (this.slideProp=="acc") {

		this.distX=-this.distX; this.distY=-this.distY;

		this.startX=this.destX; this.startY=this.destY;

	}

	this.sliding=true;

	this.doSlide();

}



dynObj.prototype.slideBy = function(dx,dy,slideTime,fn,container) {

	var destX=this.x+dx; var destY=this.y+dy;

	this.slideTo(destX,destY,slideTime,fn,container);

}



dynObj.prototype.doSlide = function() {

	if (!this.sliding) return;	// slide can be interrupted

	var elapsed = (new Date()).getTime()-this.slideStart;

	if (elapsed<this.slideTime) {

		if (this.slideProp=="dec") {

			var x = Math.round((this.distX)*Math.sin(this.per*elapsed)+this.startX);

			var y = Math.round((this.distY)*Math.sin(this.per*elapsed)+this.startY);

		} else if (this.slideProp=="acc") {

			var x = Math.round((this.distX)*Math.cos(this.per*elapsed)+this.startX);

			var y = Math.round((this.distY)*Math.cos(this.per*elapsed)+this.startY);

		} else {

			var x = Math.round((this.distX)*(this.per*elapsed)+this.startX);

			var y = Math.round((this.distY)*(this.per*elapsed)+this.startY);

		}

		this.shiftTo(x,y);

		this.onSlide();

		setTimeout(this.obj+".doSlide()",35);

	} else {	// if time's up

		this.shiftTo(this.destX,this.destY);

		this.onSlide();

		this.sliding=false;

		this.onSlideEnd();

		if (this.fn) eval(this.fn);

	}

}



// do you want your slides to be steady, accelerate or decelerate?

dynObj.prototype.slideProp="dec";	// can be "steady", "acc", or "dec"



dynObj.prototype.onSlide=function() {}

dynObj.prototype.onSlideEnd=function() {}