/*

 * Resizer - a JavaScript module for dynamically animating the resizing

 * of an HTML element over time, so that it appears to grow or shrink

 *

 * Author:	Benjamin Black <benjamin.black@gmail.com>

 * Revision:	1.0

 * Link:	http://www.benjaminblack.net/js/Resize.js

 * License:	GPL (http://www.gnu.org/copyleft/gpl.html)

 * 

 * Copyright (C) 2006  Benjamin Black

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 */



var	__Resize_stateBuffer	= new Array();



var	__Resize_timeStep	= 25;



var	__Debug			= false;



function dump(obj)

{

	var s = "";

	for (i in obj)

	{

		s += i + ": " + obj[i] + "\n";

	}

	alert(s);

}





function ResizeOptions(width, height, duration, rate, animateBorder, endBorder, callback)

{

	// check the arguments for validity

	this.checkArgs(arguments);

	

	this.isWidthResized = (width != null);

	this.isHeightResized = (height != null);



	// Internet Explorer prior to version 7 does not support element dimensions of zero;

	// this code checks if the user is running IE 6 or lower and caps the width and height

	// at a minimum of one

	if (width == 0 || height == 0) {

		with (navigator.appVersion) {

			if (indexOf("MSIE") >= 0) {

				var version = parseFloat(substr(indexOf("MSIE") + 5, 3));

				 if (version <= 6.0) {	

				 	if (width == 0)

				 		width = 1;

				 	if (height == 0)

				 		height = 1;

				 }

			}

		}

	}

	

	this.endWidth = width;

	this.endHeight = height;

	this.duration = duration;

	this.rate = rate;

	this.animateBorder = animateBorder;

	this.endBorder = endBorder;

	this.callback = callback;

}







ResizeOptions.prototype.checkArgs = function(args)

{

	var width, height, duration, rate, animateBorder, endBorder, callback;

	width = args[0]; 

	height = args[1]; 

	duration = args[2]; 

	rate = args[3]; 

	animateBorder = args[4]; 

	endBorder = args[5];

	callback = args[6];



	try {

		if (width != null) {

			if (width < 0)

				throw new Error("ResizeOptions: 'width' must be a greater than or equal to zero.");

			if (width % 1 != 0)

				throw new Error("ResizeOptions: 'width' must be a whole number.");

		}

		

		if (height != null) {

			if (height < 0)

				throw new Error("ResizeOptions: 'height' must be greater than or equal to zero.");

			if (height % 1 != 0)

				throw new Error("ResizeOptions: 'height' must be a whole number.");

		}

		

		if (duration == null && rate == null)

			throw new Error("ResizeOptions: either 'duration' or 'rate' must be specified (cannot both be null).");

		

		if (duration != null) {

			if (typeof duration != "number")

				throw new Error("ResizeOptions: 'duration' must be a number.");

			else {

				if (duration < __Resize_timeStep)

					throw new Error("ResizeOptions: 'duration' must be at least " + __Resize_timeStep + ".");

				if (duration % 1 != 0)

					throw new Error("ResizeOptions: 'duration' must be a whole number.");

			}

		}

			

		if (rate != null) {

			if (typeof rate != "number")

				throw new Error("ResizeOptions: 'rate' must be a number.");

			else {

				if (rate <= 0)

					throw new Error("ResizeOptions: 'rate' must be greater than zero.");

				if (rate % 1 != 0)

					throw new Error("ResizeOptions: 'rate' must be a whole number.");

			}

		}

		

		if (animateBorder != null && typeof animateBorder != "string")

			throw new Error("ResizeOptions: 'animateBorder' must be a string representing a valid CSS border.");

		

		if (endBorder != null && typeof endBorder != "string")

			throw new Error("ResizeOptions: 'endBorder' must be a string representing a valid CSS border.");

			

		if (callback != null && typeof callback != "function")

			throw new Error("ResizeOptions: 'callback' must be a valid function.");

	}

	catch (e) {

		alert(e);

		throw e;

	}



}











function __Resize_state(id, element, options, 

		currentWidth, widthStep, widthComp,

		currentHeight, heightStep, heightComp)

{

	this.id = id;

	this.element = element;

	this.options = options;

	this.currentWidth = currentWidth;

	this.widthStep = widthStep;

	this.widthComp = widthComp;

	this.currentHeight = currentHeight;

	this.heightStep = heightStep;

	this.heightComp = heightComp;

	this.timeoutID = null;

	

	this.toString = function()

	{

		return	"id: " + id + "\n" +

			"element: " + element + "\n" +

			"isWidthResized: " + options.isWidthResized + "\n" +

			"isHeightResized: " + options.isHeightResized + "\n" +

			"width: " + options.width + "\n" +

			"height: " + options.height + "\n" +

			"duration: " + options.duration + "\n" +

			"animateBorder: " + options.animateBorder + "\n" +

			"endBorder: " + options.endBorder + "\n" +

			"callback: " + options.callback + "\n" + 

			"currentWidth: " + currentWidth + "\n" + 

			"widthStep: " + widthStep + "\n" + 

			"widthComp: " + widthComp + "\n" +

			"currentHeight: " + currentHeight + "\n" +

			"heightStep: " + heightStep + "\n" + 

			"heightComp: " + heightComp + "\n" +

			"timeoutID: " + timeoutID;

	}

}







function resize(element, id, options)

{	

	if (element == null || element.style == null)

		throw new Error("resize: 'element' must be a valid object with a 'style' attribute");



	if (id == null)

		id = "__Resize_global";

	

	if (typeof id == "object")

		id = id.toString();

		

	if (typeof id != "string" && typeof id != "number")

		throw new Error("resize: 'id' must be a valid object, string, or number");

		

	if (!(options instanceof ResizeOptions))

		throw new Error("resize: 'options' must be an instance of ResizeOptions");

		



	var state = __Resize_stateBuffer[id];

	if (state != null) {

		if (state.timeoutID != null)

			clearTimeout(state.timeoutID);

		state = __Resize_stateBuffer[id] = null;

	}



	var currentWidth, widthComp, widthStep;

	var currentHeight, heightComp, heightStep;



	var isUsingDuration = (options.duration != null);

	

	if (!options.isWidthResized) {

		currentWidth = widthComp = widthStep = null;

	}

	else {

		currentWidth = element.clientWidth;

		widthComp = (currentWidth < options.endWidth) ? Math.min : Math.max;

		if (isUsingDuration) {

			var percentChange = __Resize_timeStep / options.duration;

			widthStep = ((widthStep = (options.endWidth - currentWidth) * percentChange) > 0) ? 

					Math.max(1, Math.round(widthStep)) :

					Math.min(-1, Math.round(widthStep));

		}

		else {

			widthStep = options.rate * __Resize_timeStep / 1000;

		}

	}

	

	if (!options.isHeightResized) {

		currentHeight = heightComp = heightStep = null;

	}

	else {

		currentHeight = element.clientHeight;

		heightComp = (currentHeight < options.endHeight) ? Math.min : Math.max;

		if (isUsingDuration) {		

			var percentChange = __Resize_timeStep / options.duration;

			heightStep = ((heightStep = (options.endHeight - currentHeight) * percentChange) > 0) ?

					Math.max(1, Math.round(heightStep)) :

					Math.min(-1, Math.round(heightStep));

		}

		else {

			heightStep = options.rate * __Resize_timeStep / 1000;

			if (options.endHeight - currentHeight >= 0)

				heightStep = Math.abs(heightStep);

			else

				heightStep = -Math.abs(heightStep);

				

		}

	}

	

	var isWidthResized = (widthStep != null);

	var isHeightResized = (heightStep != null);

	

	state = new __Resize_state(id, element, options, 

					currentWidth, widthStep, widthComp,

					currentHeight, heightStep, heightComp);

	if (__Debug)

		dump(state);

	__Resize_stateBuffer[id] = state;

	if (options.animateBorder != null)

		element.style.border = options.animateBorder;

	__resize(id);

}







function __resize(id)

{

	var state = __Resize_stateBuffer[id];

	state.timeoutID = null;

	

	with (state)

	{

		if (options.isWidthResized) {

			currentWidth = widthComp(currentWidth + widthStep, options.endWidth);

			element.style.width = currentWidth + "px";

		}

		if (options.isHeightResized) {

			currentHeight = heightComp(currentHeight + heightStep, options.endHeight);

			element.style.height = currentHeight + "px";

		}

		

		if (currentWidth != options.endWidth || currentHeight != options.endHeight) {

			timeoutID = setTimeout("__resize(\""+id+"\");", __Resize_timeStep);

		}

		else {

			__Resize_stateBuffer[id] = null;

			if (options.endBorder != null)

				element.style.border = options.endBorder;

			if (options.callback != null)

				options.callback(state);

		}

	}

}