/*
                  *************************
                  *     Javascript        *
                  *     g02.js            *
                  *     May 30, 2022      *
                  *     Arlon Staywell    *
                  *************************
*/

function init()
{	ogm.innerHTML=txt[0];
	section1=$('noScripts');
	section1.style.display='none';
	section2=$('gotScripts');
	section2.style.display='block';
	initCanvas();
}

function initCanvas()
{   var canvas = $('cnvs');
	if (canvas.getContext)
	{ccc = canvas.getContext('2d');}
}

function selmode(n)
{	gmode=n;
	ogm.innerHTML=txt[n];
	initGraph();
	switch(gmode)
	{	case 0: CirSz(radg,radgin); break
		case 1: CirSlc(); break
	}
}

function udt()
{	kWhouse=900;
	kWcar=30*(ncars.value*=1);
	opt0.innerHTML=(ncars.value*=1);
	kWhouse=kWhouse+kWcar;
	kWhouse=kWhouse/30;
	kWhouse=kWhouse/24;
	kWhouse=kWhouse*Math.pow(10,3);
	cap=2*Math.pow(10,9);
	nHouse=(cap/kWhouse);
	nHouseInt=cnv2int(nHouse);
	opt1.innerHTML=(nHouseInt+="");
	nPop=nHouse*2.53;
	sqMi=nPop/150;
	sqMiInt=cnv2int(sqMi);
	opt2.innerHTML=(sqMiInt+="");
	rad=Math.sqrt(sqMi/(Math.PI));
	radInt=cnv2int(rad);
	opt3.innerHTML=(radInt+="");
	pHouse=1-nHouse/1600000;
	opHouse=fix5(pHouse*100);
	opt4.innerHTML=opHouse+'%';
	radg=rad*1.5;
	radgin=radg*(2/3);

	initGraph();
	switch(gmode)
	{	case 0: CirSz(radg,radgin); break
		case 1: CirSlc(); break
	}
}

function initGraph()
{	ccc.clearRect(1,1,298,298);
	ccc.beginPath();
	ccc.strokeStyle = 'rgb(0,0,0)';
	ccc.lineWidth = 1;
	ccc.strokeRect(0,0,298,298);
}
	
function CirSz(ri,ro)
{	lG=ccc.createRadialGradient(150,150,ro,150,150,ri);
	lG.addColorStop(0,'rgba(255,0,0,0.55)');
	lG.addColorStop(1,'rgba(255,255,255,0)');
	ccc.fillStyle=lG;
	ccc.fillRect(0,0,298,298);
	star(150,150,9,2.5);
}

function CirSlc()
{	CirSz(138,92);
	s=Math.PI*3/2;
	q=pHouse*Math.PI*2;
	e=s+q;
	ccc.fillStyle='rgba(255,255,255,0.95)';
	ccc.arc(150,150,125,s,e,false);
	ccc.fill();
	star(150,150,9,2.5);
}

//////

function $(id)
{return document.getElementById(id);}

function fix5(n)
{	s=n+='';
	if (s.length > 5)
	{s=s.substring(0,6);}
	return s;
}

function cnv2int(n)
{
  n+=''; var m; var p;
    p=n.indexOf('.')
	  if(p>-1)
		{
		  m=n.substring(0,p);
		  n=m;
        }
  return n*=1;
}

function star(x,y,r,f)
{	a1=Math.PI/10; a2=a1*3;
	sa1=Math.sin(a1); sa2=Math.sin(a2);
	ca1=Math.cos(a1); ca2=Math.cos(a2);
	ccc.beginPath();
	ccc.strokeStyle='rgb(0,0,0)';
	ccc.moveTo(x,(y-r));                    // start
	ccc.lineTo(x+(ca2*r/f),y-(sa2*r/f));    // 1
	ccc.lineTo(x+(ca1*r),y-(sa1*r));        // 2
	ccc.lineTo(x+(ca1*r)/f,y+(sa1*r)/f)     // 3
	ccc.lineTo(x+(ca2*r),y+(sa2*r));        // 4
	ccc.lineTo(x,y+r/f);                    // 5
	ccc.lineTo(x-(ca2*r),y+(sa2*r));        // 6
	ccc.lineTo(x-(ca1*r)/f,y+(sa1*r)/f);    // 7
	ccc.lineTo(x-(ca1*r),y-(sa1*r));        // 8
	ccc.lineTo(x-(ca2*r)/f,y-(sa2*r)/f);    // 9
	ccc.lineTo(x,(y-r));                    // 10
	ccc.stroke();
	ccc.fillStyle='rgb(0,0,0)';
	ccc.fill();
}

//////