/* These notices must be untouched at all times.
wz_grapher.js

Copyright (c) 2003 Walter Zorn. All rights reserved.
Created 30. 9. 2003 by Walter Zorn (Web: http://www.walterzorn.com )
Last modified: 28. 3. 2007

The latest version is available at
http://www.walterzorn.com
or http://www.devira.com
or http://www.walterzorn.de

Cross-browser JavaScript function grapher.

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
at http://www.gnu.org/copyleft/gpl.html for more details.
*/


/***********  Config variables  **********/

var BORDERCOLOR	= '#d6d6d6';
var FRAMECOLOR	= '#e6dec8';
var CNVCOLOR	= '#ffffff';
var SCALECOLOR	= '#000000';
var AXCOLOR		= '#acb098';	//'#A0A0A0';
var GRIDCOLOR	= '#dddfd3';	//'#E8E8E8';

var GRAPHCOLOR	=['63a9f6',	//	blue	
				  'fba90a',	//	orange	
				  '88b22c',	//	green	
				  '194a77',
				  'acb098',
				  '4687c9',
				  'dddfd3',
				  'cc6633'];



if (typeof DEFW	  == 'undefined')	var DEFW	= 520;			// default width and height of canvas		
if (typeof LEFT	  == 'undefined')	var LEFT	=  50;			// left margin containing y-hash layer		
if (typeof TOP	  == 'undefined')	var TOP		=   4;			// top   "									
if (typeof RIGHT  == 'undefined')	var RIGHT	=  24;			// right "  containing options				
if (typeof BOTTOM == 'undefined')	var BOTTOM	=  22;			// bottom margin containing x-hash layer	


/*********   End config variables   ***********/







var	g_frame,
	g_inputTb,
	g_cnv,				// canvas				
	g_gridlyr,
	g_xlyr, g_ylyr,		// layers for x- and y-hash					
	g_termlyr,			// termstring-layer on bottom of canvas		
	g_coordtip,			// tooltip displaying mouse-co-ordinates	
	g_n = 0,			// number of graphs on cnv					
	g_htm = '',
	g_term,
	g_w, g_h,			// size of cnv			
	g_xa, g_xz,			// x min, x max			
	g_ya, g_yz,
	g_dx, g_dy,			// delta value/px		
	g_pageX, g_pageY,	// position of canvas	
	g_wait = 0,
	g_infin = 100000000000000000000,

	g_adhtm,
	g_dom,

	g_moz,
	g_ua	= navigator.userAgent.toLowerCase(),
	g_ie	= !!(!window.opera && document.all && (document.documentElement || document.body)),
	g_iemac	= !!(g_ie && g_ua.indexOf('mac') >= 0),
	g_kq	= !!(g_ua.indexOf('konqu') >= 0),
	g_db	= document.documentElement || document.body || null;






function init(o)
	{
	g_frame = getDiv('graphframe');

	if (!g_frame) return;

	g_w = g_h = DEFW;

	o = g_frame.style;

	o.width		 = (LEFT+g_w+1+RIGHT )+'px';
	o.height	 = (TOP +g_h  +BOTTOM)+'px';
//	o.background = FRAMECOLOR;

	g_inputTb = getDiv('inputs');
//	g_inputTb.style.background	= FRAMECOLOR;

	g_inputTb.style.width		= (g_w+1+LEFT+RIGHT)+'px';

//	o.borderBottom = o.borderRight = o.borderLeft = g_inputTb.style.borderTop = g_inputTb.style.borderRight = g_inputTb.style.borderLeft = '1px solid '+BORDERCOLOR;

	g_adhtm = (typeof g_frame.insertAdjacentHTML != "undefined");

	g_dom = (!g_adhtm && typeof g_frame.appendChild								!= "undefined"
					  && typeof document.createRange							!= "undefined"
					  && typeof document.createRange().setStartBefore			!= "undefined"
					  && typeof document.createRange().createContextualFragment != "undefined");

	g_moz = document.body && typeof document.body.style.MozOpacity != "undefined";

	getCnvPos();

	paint(g_frame,	mkDiv('', '',		LEFT,	TOP,		g_w+1,	g_h+1,	CNVCOLOR,	'bglyr'		)+
					mkDiv('', '',		LEFT,	TOP,		g_w+1,	g_h+1,	'',			'gridlyr'	)+
					mkDiv('', '',		LEFT,	TOP,		g_w+1,	g_h+1,	'',			'cnvlyr'	)+
					mkDiv('', '',		LEFT,	TOP+g_h+1,	g_w+1,	BOTTOM,	'',			'xlyr', true)+
					mkDiv('', 'right',	0,		TOP,		LEFT,	g_h+1,	'',			'ylyr', true));


	(o = (g_cnv = getDiv('cnvlyr')).style).zIndex = 1;
	o.cursor	= 'crosshair';
	g_xlyr		= getDiv('xlyr'	  );
	g_ylyr		= getDiv('ylyr'	  );
	g_gridlyr	= getDiv('gridlyr');
	g_termlyr	= getDiv('terms'  );


	if (document.captureEvents) document.captureEvents(Event.MOUSEMOVE);

	window.onresize = getCnvPos;



	if (window.mkGraph)
		{
		mkGraph (document.getElementById("fo"));
		}
	}






function isNum(x)
	{
	return (!isNaN(x) && typeof x == 'number');
	}





function getDiv(x)
	{
	x = !!document.all? document.all[x] : !!document.getElementById? document.getElementById(x) : null;
	return (x && typeof x.style != 'undefined' && typeof x.innerHTML != 'undefined')? x : null;
	}





function getCnvPos(o)
	{
	g_pageX = LEFT+1;
	g_pageY = TOP;
	o = g_frame;

	while (o.offsetParent)
		{
		g_pageX += o.offsetLeft;
		g_pageY += o.offsetTop;
		o = o.offsetParent;
		}
	}





function getVal(el, y)
	{
	return ((y = el.value.replace(/ /g, '')) == '' || !isNaN(y = parseFloat(y.replace(/\,/,'.'))))? y : 'n';
	}





function alertErr (el,str)
	{
	alert (S_ERR_BASE + str);
	el.focus ();
	el.select();
	}





function setCssWH (o,w,h,over)
	{
	o.style.width  = w+'px';
	o.style.height = h+'px';

	if (!over)
		{
		o.style.clip	 = 'rect(0,'+w+'px,'+h+'px,0)';
		o.style.overflow = 'hidden';
		}
	}





function resizeCnv()
	{
	g_inputTb.style.width = (LEFT+g_w+1+RIGHT)+'px';

	setCssWH (g_frame,			LEFT+g_w+1+RIGHT, Math.max(350, TOP+g_h+BOTTOM));
	setCssWH (getDiv('bglyr'),	g_w+1,	g_h+1);
	setCssWH (g_cnv,			g_w+1,	g_h+1);
	setCssWH (g_gridlyr,		g_w+1,	g_h+1);
	setCssWH (g_ylyr,			LEFT,	g_h+1,	true);
	setCssWH (g_xlyr,			g_w+1,	BOTTOM,	true);

	g_xlyr.style.top = (TOP+g_h+1)+'px';
	}






function fitWnd()
	{
	if (document.forms.fo.FITWND.checked)
		{
		if (!!((o = document.documentElement || document.body) && o.clientWidth))
			{
			var _w = o.clientWidth;
			var _h = o.clientHeight;
			}
		else
			{
			var _w = window.innerWidth;
			var _h = window.innerHeight;
			}

		g_w = g_h = Math.min(_w-_w%2-LEFT-RIGHT, _h-_h%2-TOP-BOTTOM)-4;
		}
	  else g_w = g_h = DEFW;

	resizeCnv();
	getCnvPos();
	}




function initCoordtip(o)
	{
	(o = (g_coordtip = getDiv('coordtip')).style).left = (g_pageX+15)+'px';
	o.top = (g_pageY+10)+'px';
	o.zIndex = 2;
	paint(g_coordtip, '<small style="background:'+CNVCOLOR+';white-space:nowrap;">'+S_COORDTIP+'<\/small>');
	g_cnv.onmouseover = function() {document.onmousemove = coordTip; g_cnv.onmouseover = null;}
	}





function prt()
	{
	getDiv('body1').style.display = getDiv('body2').style.display = (document.forms.fo.PRT.checked)? 'none' : 'block';
	getCnvPos();
	}





function setGridVis()
	{
	g_gridlyr.style.visibility = (document.forms.fo.GRID.checked)? 'visible' : 'hidden';
	}





function delGraphs(ask)
	{
	if (ask && !(g_n && window.confirm(S_DELGRAPHS))) return;
	g_n = 0;
	paint(g_cnv,	 '');
	paint(g_termlyr, '');
	}





String.prototype.toExp = function()
	{
	var neg = (this.charAt(0) == '-')*1;
	var n	= this.match(/[1-9]/g).length;

	if (Math.abs(parseFloat(this)) > 1)
		return this.substring(0,neg+1) + ((n-1)? ('.'+this.substring(neg+1, this.indexOf('0'))) : '') + '*10<sup>' + (this.length-1-neg) + '<\/sup>';

	return (neg? '-' : '') + this.match(/[1-9]/)[0] + ((n-1)? ('.'+this.substring(this.length-n+1)) : '') + '*10<sup>-' + (this.substring(this.indexOf('.')+1).length-n+1) + '<\/sup>';
	}





function shiftL(x, n)
	{
	x = ''+Math.abs(x);

	while (n--)
		{
			 if (x.charAt(x.length-1) == '0')	x = x.substring(0, x.length-1);
		else if (!(/\./).test(x))				x = x.substring(0, x.length-1)+'.'+x.charAt(x.length-1);
		else if (!x.indexOf('.'))				x = '.0'+x.substring(1);
		else									x = x.substring(0, x.indexOf('.')-1)+'.'+x.charAt(x.indexOf('.')-1)+x.substring(x.indexOf('.')+1);
		}

	return	  ((x<0				)?'-':'')
			+ ((x.charAt(0)=='.')?'0':'')
			+ x;
	}





function mkIv(x)
	{
	x *= DEFW/g_w;;

	var i = 0;

	while (x-100 <= 0)
		{
		x *= 10;
		i++;
		}

	while (x-1000 > 0)
		{
		x /= 10;
		i--;
		}

	x = Math.floor(x);
	x = (x-600 >= 0)? 100 : (x-300 >= 0)? 50 : (x-200 >= 0)? 25 : 20;

	while (i < 0)
		{
		x = parseInt(x += '0');
		i++;
		}
	return parseFloat(shiftL(x, i));
	}





function mkNumStr(n, iv, toE)
	{
	var i = 0;

	if (!n || !iv) return '0';

	while (Math.abs(iv)-1 < 0)
		{
		iv *= 10;
		i++;
		}

	n = shiftL(!toE? Math.round(n*iv) : (n*iv), i);
	return (toE && n.length > 6)? n.toExp() : n;
	}





function mkScale()
	{
	var ivx = mkIv(g_xz-g_xa), ivy = mkIv((g_yz-g_ya)*g_w/g_h),
	rx = ivx/g_dx, ry = ivy/g_dy,

	htm = '', gridhtm = '',
	pos, str, strs, strl,
	limt = Math.round(g_xz/g_dx), limb = Math.round(g_xa/g_dx),
	j = Math.ceil(g_xa/ivx),
	i = Math.round(j*rx);

	while (i-limt <= 0)
		{
		strs = (str = ''+mkNumStr(j, ivx, true)).match(/[^\>\<a-z]+/g);
		strl = strs[0].length + (strs[1]? strs[1].length : 0);
		htm += mkDiv('', '', (pos = i-limb), 0, 1, 4, SCALECOLOR, '', false, true)+
			mkDiv('<font style="font-size:11px;font-family:Arial,Helvetica,sans-serif;color:black;">'+str+'<\/font>', '', pos-3*strl, 4, 16*strl, 12, '', '', true, false);
		gridhtm += mkDiv('', '',  pos, 0, 1, g_h+1, !j? AXCOLOR : GRIDCOLOR, '', false, true);
		i = Math.round(++j*rx);
		}

	paint(g_xlyr, htm);

	var sclw = parseInt(g_ylyr.style.width);

	htm = '';
	limt = Math.round(g_yz/g_dy), limb = Math.round(g_ya/g_dy);
	j = Math.ceil(g_ya/ivy);
	i = Math.round(j*ry);

	while (i-limt <= 0)
		{
		strl = (str = ''+mkNumStr(j, ivy, true)).length;
		htm += mkDiv('', '', sclw-4, (pos = g_h-i+limb), 4, 1, SCALECOLOR, '', false, true)+
			mkDiv('<font style="font-size:11px;font-family:Arial,Helvetica,sans-serif;color:black;">'+str+'<\/font>', 'right', 0, pos-7, sclw-6, 12, '', '', true, false);
		gridhtm += mkDiv('', '',  0, pos, g_w+1, 1, !j? AXCOLOR : GRIDCOLOR, '', false, true);
		i = Math.round(++j*ry);
		}

	paint(g_ylyr, htm);
	paint(g_gridlyr, gridhtm);
	}







function mkDiv (txt, align, x, y, w, h, c, id, over, cut)
	{
	if (cut)
		{
		if (x-g_w > 0 || x+w < 0 || y-g_h > 0 || y+h < 0) return '';

		if (y < 0)
			{
			h += y;
			y = 0;
			}

		if (h > g_h+1-y)
			h = g_h+1-y;

		if (x < 0)
			{
			w += x;
			x = 0;
			}

		if (w > g_w+1+x)
			w = g_w+1+x;
		}

	if (g_ie) return ('%%'+x+';'+y+';'+w+';'+h+';'+(align? 'righ;' : 'lef;')+(c? (c+';') : ';')+(over? 'visible;' : 'hidden;')+(id? (' id="'+id+'">') : '>')+txt);

	return ('<div'+	(id?' id="'+id+'"' : '')+
			' style="position:absolute;left:' + x + 'px;top:' + y + 'px;width:' + w + 'px;height:' + h + 'px;'+
			(over? '' : ('clip:rect(0,' + w + 'px,' + h + 'px,0);' + (g_moz? '' : 'overflow:hidden;')))+
			(c? 'background-color:' + c + ';' : '')+
			'text-align:' + (align || 'left') + ';">' + txt + '<\/div>'	);
	}






function gReplace(x)
	{
	return x.replace(/%%([^;]+);([^;]+);([^;]+);([^;]+);([^;]+);([^;]*);([^;]+);([^%%]*)/g,
		'<div style="position:absolute;left:$1px;top:$2px;width:$3px;height:$4px;text-align:$5t;'+
		'background:$6;overflow:$7;"$8<\/div>');
	}





function paint(cnv, htm, add)
	{
	if (cnv)
		{
		if (add)
			{
			var o;

			if (g_adhtm)
				cnv.insertAdjacentHTML("BeforeEnd", gReplace(htm));
			  else
				if (g_dom)
					{
					o = document.createRange();
					o.setStartBefore(cnv);
					o = o.createContextualFragment(htm);
					cnv.appendChild(o);
					}
				  else
					cnv.innerHTML += htm;
			}
		  else
			cnv.innerHTML = g_ie? gReplace(htm) : htm;
		}
	}





function scaleY(x)
	{
	return (Math.min(Math.max(g_h+Math.round((g_ya-x)/g_dy), -1), g_h+1));
	}




function mkTerm(x)
	{
	x = x.toLowerCase().replace (/\s/g,										''			).
						replace (/f(\(|\{|\[)x(\)|\}|\])\=/g,				''			).
						replace (/math\./g,									''			).
						replace (/\.*\;+/g,									';'			).
						replace (/[\.\;]*$/,								''			).
						replace (/\|([^\|]*)\|/g,							'abs($1)'	).
						replace (/:/g,										'\/'		).
						replace (/²/g,										'^2'		).
						replace (/³/g,										'^3'		).
						replace (/[\"\']/g,									'^'			).
						replace (/e/g,										'E'			).
						replace (/log(\d)/g,								'LOG$1'		).
						replace (/ln(\d)/g,									'LN$1'		).
						replace (/arc(us)?|arEa|ar/g,						'a'			).
						replace (/hyp(Erbolicus)?/g,						'h'			).
						replace (/cosin(us|E)?/g,							'cos'		).
						replace (/sin(us|E)/g,								'sin'		).
						replace (/sEc(an(s|t))?/g,							'sec'		).
						replace (/cosec/g,									'csc'		).
						replace (/tangEn[st]/g,								'tan'		).
						replace (/cotan/g,									'cot'		).
						replace (/random(\(|\{|\[)(\)|\}|\])|rand(om)?/g,	'random()'	).
						replace (/(p|power)(\(|\{|\[)/g,					'pow$2'		).
						replace (/(b|q)r(\(|\{|\[)/g,						'$1rt$2'	).
						replace (/(sqr|sqrt)(\d)/g,							'SQRT$2'	).
						replace (/tan2/g,									'tanz'		).
						replace (/max/g,									'maz'		).
						replace (/pi/g,										'PI'		).
						replace (/phi/g,									'PHI'		).
						replace (/y/,										'nuts'		).
						replace (/cEil/g,									'ceil'		).
						replace (/Expow|Exp/g,								'exp'		).
						replace (/([^m]|^)(\(|\{|\[)(\)|\}|\])/g,			'$1$2x$3'	).
						replace (/(\(|\{|\[)\,/g,							'$1x,'		).
						replace (/\,(\)|\}|\])/g,							',x$1'		).
						replace (/\,\,/g,									',x,'		);

	x = x.replace (/([^G]\d\d|[^G\d]\d|^\d|^\d\d)E/g,	'$1*E');
	x = x.replace (/(RT1_2|RT2|LN10|LN2)(\d)/g,			'$1*$2');

	var reg = /(x|E|PI|\)|\}|\])(E|\d)/g;

	while (x.match(reg)) x = x.replace(reg,'$1*$2');

	reg = /(\d|E|PI|x|\)|\}|\])(\(|\{|\[|x|a|c|exp|f|gaus|l|m|pow|r|s|tan|L|PI|SQRT)/g;

	while (x.match(reg)) x = x.replace(reg,'$1*$2');

	x = x.replace(/tanz/g,'tan2').replace(/maz/g,'max');

	return x;
	}




function WzMath()
	{
	this.PHI	= 1.6180339887498948482045868343656;
	this.root	= function(x, xp)	{return Math.pow(x, 1/xp);					};
	this.cbrt	= function(x)		{return Math.pow(x, 1/3);					};
	this.logn	= function(x, bs)	{return Math.log(x)/Math.log(bs);			};
	this.ln		= function(x)		{return Math.log(x);						};
	this.lg		= function(x)		{return Math.log(x)/Math.LN10;				};
	this.lb		= function(x)		{return Math.log(x)/Math.LN2;				};
	this.cot	= function(x)		{return Math.cos(x)/Math.sin(x);			};
	this.sec	= function(x)		{return 1/Math.cos(x);						};
	this.csc	= function(x)		{return 1/Math.sin(x);						};
	this.acot	= function(x)		{return Math.atan(-x)+Math.PI/2;			};
	this.asec	= function(x)		{return Math.acos(1/x);						};
	this.acsc	= function(x)		{return Math.asin(1/x);						};
	this.sinh	= function(x)		{return (Math.exp(x)-Math.exp(-x))/2;		};
	this.cosh	= function(x)		{return (Math.exp(x)+Math.exp(-x))/2;		};
	this.sech	= function(x)		{return 2/(Math.exp(x)+Math.exp(-x));		};
	this.csch	= function(x)		{return 2/(Math.exp(x)-Math.exp(-x))	;	};
	this.tanh	= function(x)		{return (Math.exp(2*x)-1)/(Math.exp(2*x)+1);};
	this.coth	= function(x)		{return (Math.exp(2*x)+1)/(Math.exp(2*x)-1);};
	this.asinh	= function(x)		{return Math.log(x+Math.sqrt(x*x+1));		};
	this.acosh	= function(x)		{return Math.log(x+Math.sqrt(x*x-1));		};
	this.atanh	= function(x)		{return Math.log((1+x)/(1-x))/2;			};
	this.acoth	= function(x)		{return Math.log((x+1)/(x-1))/2;			};
	this.asech	= function(x)		{return Math.log(1/x+Math.sqrt(1/(x*x)-1));	};
	this.acsch	= function(x)		{return Math.log(1/x+Math.sqrt(1/(x*x)+1));	};
	this.gaussd	= function(x,m,s)	{return 1/(s*2.5066282746310002)*Math.exp(-(x -= m)*x/(2*s*s));};
	this.sgn	= function(x)		{return (x < 0)? -1 : (x > 0)? 1 : 0;		};
	this.fact	= function(x)
					{
					x = Math.round(Math.abs(x));
					return (x>1) ? x*this.fact(x-1) : 1;
					};
	}




WzMath.prototype = Math;
WzMath = new WzMath();




function mkPow(x)
	{
	x = x.replace(/\{|\[/g,'(').replace(/\}|\]/g,')');

	while (/\^/.test(x))
		{
		var az = x.search(/\^/),
		a = x.substring(0, az), z = x.substring(az+1),
		p = 0, ch, lim = az-1;

		while (true)
			{
			ch = a.charAt(lim);
			if (ch == ')') p++;
			else if (ch == '(') p--;
			if (p < 0 || !p && (!(lim+1) || /[\+\-\*\/\,]/.test(ch))) break;
			lim--;
			}

		a = a.substring(0, lim+1) + 'pow(' + a.substring(lim+1, az);
		lim = 0; p = 0;

		while (true)
			{
			ch = z.charAt(lim);
			if (ch == '(') p++;
			else if (ch == ')') p--;
			if (p < 0 || !p && (lim == z.length || lim > 0 && /[\+\-\*\/\^\,]/.test(ch))) break;
			lim++;
			}

		z = z.substring(0, lim) + ')' + z.substring(lim);
		x = a+','+z;
		}

	return x;
	}





Number.prototype.lim = function(i, j, xdir, ydir)
	{
	var yy = parseFloat(this), y,
	incr = g_dx/100, _incr = incr*xdir, qt = 1, lim = (g_xa+(j+xdir)*g_dx),
	x = g_xa+j*g_dx;
	while (qt < 0x100000 && !!((xdir < 0)? (x-lim > 0) : (x-lim < 0)))
	{
		x += _incr;
		y = gEval(x, g_term[i]);
		if (isNum(y) && y*ydir-yy*ydir > 0) yy = y;
		else
		{
			x -= _incr;
			_incr = incr*xdir/(qt <<= 3);
		}
	}
	return yy;
	}




function gEval(x, term, y)
	{
	with (WzMath)	return Math.min(Math.max(parseFloat(eval(term)),-g_infin),g_infin);
	}




function mkGraph(f)
	{
	if (!g_cnv)
		{
		alert(S_OLDBROWSER);
		return;
		}

	g_htm = '';

	var xa = getVal(f.XA);
	var xz = getVal(f.XZ);

	if (!isNum(xa))	 return alertErr (f.XA, 'x min');
	if (!isNum(xz))	 return alertErr (f.XZ, 'x max');
	if (xa >= xz)	 return alertErr (f.XA, S_ERR_XRANGE);

	if (!f.Add.checked) g_n = 0;

	if (!g_n)
		{
		var ya = getVal(f.YA);
		var yz = getVal(f.YZ);

		if (!isNum(ya) && ya != '')  return alertErr (f.YA, 'y min');
		if (!isNum(yz) && yz != '')  return alertErr (f.YZ, 'y max');
		if ( isNum(ya)
		  && isNum(yz) && ya >= yz)  return alertErr (f.YA, S_ERR_YRANGE);

		fitWnd();

		g_xa = xa;
		g_xz = xz;
		g_dx = (xz-xa)/g_w;
		g_ya = ya;
		g_yz = yz;

		if (!isNum(ya)) ya =  g_infin;
		if (!isNum(yz)) yz = -g_infin;

		delGraphs();
		}

	g_term = mkTerm(f.F.value).split(';');

	var term = [];
	var yy = [], y;

	try
		{
		for (i = 0; i < g_term.length; i++)
			{
			g_term[i] = mkPow(term[i] = g_term[i]);

			while (true)
				{
				var coms = (g_term[i].match(/\,/g) || []).length, meths = (g_term[i].match(/pow|min|max|atan2|root|logn|gau|ssd?/g) || []).length;

					 if (coms > meths && g_term[i].match(/\d+\,\d/))	return alertErr (f.F, S_ERR_TDECI	 );
				else if (coms > meths)									return alertErr (f.F, S_ERR_TCOMM	 );
				else if (coms < meths)									return alertErr (f.F, S_ERR_TMISSCOMM);
				else break;
				}

			if (/\|/.test(g_term[i]))	return alertErr(f.F, S_ERR_TPIPE);

			if ((g_term[i].match(/\(/g) || []).length != (g_term[i].match(/\)/g) || []).length)		return alertErr(f.F, S_ERR_TPARENTH);

			var rand = !(g_term[i].indexOf('ran') < 0);
			yy[i] = [];
			yy[i][g_w] = gEval(g_xz, g_term[i]);

			var j = g_w+1;

			while (j--)
				{
				if (j) yy[i][j-1] = gEval(g_xa+(j-1)*g_dx, g_term[i]);

				if (isNum(y = yy[i][j]))
					{
					if (!rand)
						{
						if (isNum(yy[i][j-1]) && isNum(yy[i][j+1]))
							{
								 if (yy[i][j-1] < 0 && y > 0 && yy[i][j+1]-y < 0)	y = y.lim(i,j,-1, 1);
							else if (yy[i][j-1] > 0 && y < 0 && yy[i][j+1]-y > 0)	y = y.lim(i,j,-1,-1);
							else if (yy[i][j+1] > 0 && y < 0 && yy[i][j-1]-y > 0)	y = y.lim(i,j, 1,-1);
							else if (yy[i][j+1] < 0 && y > 0 && yy[i][j-1]-y < 0)	y = y.lim(i,j, 1, 1);
							}
						  else	if (j-g_w && !isNum(yy[i][j+1]) && isNum(yy[i][j-1]))	y = y.lim(i,j, 1,(y-yy[i][j-1] > 0)? 1 : -1);
						  else	if (j	  && !isNum(yy[i][j-1]) && isNum(yy[i][j+1]))	y = y.lim(i,j,-1,(y-yy[i][j+1] > 0)? 1 : -1);

						yy[i][j] = y;
						}

					if (!isNum(g_ya)) ya = Math.min(ya, y);
					if (!isNum(g_yz)) yz = Math.max(yz, y);
					}
				}
			}
		}

	catch (err)
		{
		alertErr(f.F, S_ERR_TERM);
		return;
		}


	if (!g_n)
		{
		g_yz = yz;
		g_ya = ya;
		var oldh = g_h;

		if (document.forms.fo.XYRATIO.checked)
			{
			g_dy = g_dx;
			var h = (g_yz-g_ya)/g_dy;

			if (h > 100*g_w)
				{
				if (g_ya < 0 && g_ya < -g_w*g_dy) g_ya *= 100*g_w/h;
				if (g_yz > 0 && g_yz > g_w*g_dy) g_yz *= 100*g_w/h;
				}

			if (h-1 < 0) g_ya -= g_dy;
			g_h = Math.round((g_yz-g_ya)/g_dy);
			}
		  else
			{
			if (!(g_yz-g_ya))
				{
				g_ya -= (g_xz-g_xa)/2;
				g_yz += (g_xz-g_xa)/2;
				}

			g_h = g_w;
			g_dy = (g_yz-g_ya)/g_h;
			}

		if (oldh != g_h) resizeCnv();
		mkScale();
		}

	var termhtm = '', ci = 0, x;
	//var t0 = (new Date()).getTime();

	for (i = 0; i < g_term.length; i++)
		{
		var c = '#' + GRAPHCOLOR[(ci++)%GRAPHCOLOR.length];
		var tp, bot;
		var ox = g_w+1;
		var oy = '';
		var ny = (isNum(yy[i][g_w]))? scaleY(yy[i][g_w]) : '';

		x = g_w+1;

		while (x--)
			{
			y = ny;
			ny = (x && isNum(yy[i][x-1]))? scaleY(yy[i][x-1]) : '';

			if (isNum(y))
				{
				if (!isNum(oy)) oy = y;
				if (!isNum(ny))
					{
					if (ox-x-1 || !(oy-y))
					{
						tp = y;
						bot = y+1;
					}
					else if (oy-y < 0)
					{
						tp = oy;
						bot = y+1;
					}
					else
					{
						tp = y;
						bot = oy;
					}

					g_htm += mkDiv('', '', x, tp, ox-x, bot-tp, c, '', false, true);
					ox = x;
					oy = '';
					}

				else if (ny-y > 0)
				{
					if (ox-x-1)
					{
						bot = y+1;
						tp = y;
					}
					else if ((oy-y > 0 || !(oy-y) && y < 0) && ny > oy && (isNum(yy[i][x-2])? yy[i][x-2]-yy[i][x-1] >= 0 : true))
					{
						tp = y;
						bot = !isNum(yy[i][x+1])? ny : oy;
					}
					else
					{
						if (isNum(yy[i][x-2]) && scaleY(yy[i][x-2])-ny <= 0) bot = ny;
						else bot = y+Math.round((ny-y)/2);
						tp = (oy-y > 0)? y : oy;
					}
					g_htm += mkDiv('', '', x, tp, ox-x, bot-tp, c, '', false, true);
					oy = bot;
					ox = x;
				}
				else if (ny-y < 0)
				{
					if (ox-x-1)
					{
						tp = y;
						bot = y+1;
					}
					else if ((oy-y < 0 || !(oy-y) && y-g_h > 0) && ny < oy)
					{
						tp = !isNum(yy[i][x+1])? ny+1 : oy;
						bot = y+1;
					}
					else
					{
						if (isNum(yy[i][x-2]) && scaleY(yy[i][x-2])-ny >= 0) tp = ny+1;
						else tp = y-Math.floor((y-ny)/2);
						bot = (oy-y <= 0)? y+1 : oy;
					}
					g_htm += mkDiv('', '', x, tp, ox-x, bot-tp, c, '', false, true);
					oy = tp;
					ox = x;
				}
			}
			else
			{
				oy = '';
				ox = x;
			}
		}
		//term[i] = g_term[i];
		termhtm += ('<small style="color:' + c + '"><b>&mdash;&mdash; &nbsp;' + term[i].replace(/random\(\)/g,'rand').replace(/pow/g,'p').replace(/log\(/g,'ln(').replace(/rt\(/g,'r(').replace(/RT/g,'R') + '<\/b><\/small><br />');
		g_n ++;
	}
	paint(g_cnv, g_htm, true);
	//alert((new Date()).getTime()-t0);
	paint(g_termlyr, termhtm, true);

	if (!g_coordtip)
		initCoordtip();
	}







function coordTip(e)
	{
	if (g_wait) return;

	g_wait = 1;
	setTimeout('g_wait = 0;', 1);

	var x = (e = e || window.event).pageX || e.clientX || 0;
	var y =						  e.pageY || e.clientY || 0;

	if (g_ie || g_kq)
		{
		x += g_db.scrollLeft-(g_ie && !g_iemac)*2;
		y += g_db.scrollTop -(g_ie && !g_iemac)*2;
		}

	if (x-g_pageX		>= 0
	 && x-g_pageX-g_w	<= 0
	 && y-g_pageY		>= 0
	 && y-g_pageY-g_h	<= 0)
		{
		g_coordtip.style.left = (x+16)+'px';
		g_coordtip.style.top  = (y-12)+'px';

		paint (g_coordtip,	'<small style="background:'+CNVCOLOR+';white-space:nowrap;">'
						  + 'x = '+mkNumStr(x	 -g_pageX+Math.round(g_xa/g_dx), g_dx)+'&nbsp;<br />'
						  + 'y = '+mkNumStr(g_h-y+g_pageY+Math.round(g_ya/g_dy), g_dy)+'&nbsp;<\/small>', false);

		if (g_coordtip.style.visibility == 'hidden')
			g_coordtip.style.visibility = 'visible';
		}
	  else
		g_coordtip.style.visibility = 'hidden';
	}






document.write(g_ie? gReplace (mkDiv ('','',0,0,0,0,'','coordtip',true)) : mkDiv('','',0,0,0,0,'','coordtip',true));





window.onload = init;