/**copyright by Emanuele Dalla Torre - Technion 2002*/

import java.awt.*;
class KPGraph extends Canvas
	{
	private final long pointsNumber=(long)1000;

	KronigPenney kp;
	Graphics g;
	int maxX,maxY;

	KPGraph(KronigPenney kp)
		{this.kp=kp;}

	public void paint(Graphics g)
		{
		this.g=g;
		maxX=(int)getBounds().width;
		maxY=(int)getBounds().height;

		if (kp.number>0)
			{
			paintAxis();
			paintGraph();
			if(kp.effective>0)paintParabola(kp.band[kp.effective-1]);
			if(kp.valency>0)paintGap(kp.band[kp.valency-1],kp.band[kp.valency]);
			g.setColor(Color.magenta);
			g.drawString("by Emanuele D.T. - Technion V1.4",(int)((0.666)*maxX),maxY-20);
			}
		else{g.drawString(kp.errorMsg1,0,20);g.drawString(kp.errorMsg2,0,50);g.drawString(kp.errorMsg3,0,80);}
		}

	private void paintAxis()
		{
		g.setColor(Color.black);
		line(-Math.PI,0,Math.PI,0);
		line(0,0,0,kp.getMaxZ());
		//double step=Math.pow(10,Math.floor( Math.log(kp.getMaxZ())/Math.log(10) ))/5;
		double step=kp.getMaxZ()/15;
		double z=0;
		do	{
			g.drawString( "-"+(int)(z*kp.Uo*1000)+"meV",getX(0)-2,getY(z)+5) ;//needed for "0"!
			z=z+step;
			}
		while(z<=kp.getMaxZ());

		double k;
		for(int j=-5;j<6;j++)
			{
			k=(Math.PI/(5*(kp.a+kp.b)))*j;
			g.drawString( (k+"     " ).substring(0,5),getX(k),getY(0)+10) ;//needed for "0"!
			}
		}

	private void paintGraph()
		{
		g.setColor(Color.blue);
		double maxZ=kp.getMaxZ();
		double step=maxZ/pointsNumber;

		for(int n=0;n<kp.number;n++)
			{
			double oldz=kp.band[n].minZ,oldk=kp.k(oldz);
			double newk=oldk,newz=oldk;
			do	{
				newz=oldz+step;
				newk=kp.k(newz);
				if ((!Double.isNaN(newk))&&(!Double.isNaN(oldk)))
					{
					line(oldk,oldz,newk,newz);
					line(-oldk,oldz,-newk,newz);
					}
				oldk=newk;oldz=newz;
				}
			while(newz<maxZ);
			}
		}

	void paintParabola(KPBand band)
		{
		g.setColor(Color.red);
		double start=band.conduction?band.minZ:band.maxZ, end=band.conduction?band.maxZ:band.minZ;
		double step=(end-start)/pointsNumber;

		double d2=band.derivate(kp);

		double oldZ=start, oldK=0, newZ=oldZ, newK=oldK;
		while(band.conduction?(newZ<end):(newZ>end))
			{
			newZ=oldZ+step;
			newK=Math.sqrt(2*(newZ-start)/d2);
			line(oldK,oldZ,newK,newZ);
			line(-oldK,oldZ,-newK,newZ);
			oldZ=newZ;oldK=newK;
			}
		g.drawString("effective mass= "+((kp.getMe(d2)+"         ").substring(0,7))+"*me",0,maxY-20);
		}

	void paintGap(KPBand v, KPBand c)
		{
		g.setColor(Color.orange);
		line(0,v.maxZ,0,c.minZ);
		g.drawString("energy gap= "+((int)1000*(c.minZ-v.maxZ)*kp.Uo)+"meV",(int)(maxX*(0.333)),maxY-20);
		}

	private void line(double k1, double z1, double k2, double z2)
		{g.drawLine(getX(k1),getY(z1),getX(k2),getY(z2));}

	private int getX(double k)
		{return (int)(maxX/2+(k*maxX)/(2*Math.PI/(kp.a+kp.b)));}

	private int getY(double z)
		{return (int)(maxY-(z*(maxY-40))/kp.getMaxZ()-40);}

	}