import java.applet.*;
import java.awt.*; // to get Graphics object.
import java.lang.*;
import java.lang.Math.*;


public class bendGraphic 
{
	int height;
	int width;

	double twist_R;
	double twist_L;

	public bendGraphic(int w, int h, double t_R, double t_L) 
	{
		height = h; width = w; twist_R = t_R; twist_L = t_L;
	}

	public bendGraphic(int w, int h) 
	{
		this(w,h,0.0,0.0);
	}
	
	public void setSize(int w, int h) 
	{ 
		height = h; width = w; 
	}
	
	public void setTwist_L(double t_L) 
	{
		twist_L = t_L;
	}
 
	public void setTwist_R(double t_R) 
	{
		twist_R = t_R;
	}

	public void draw(Graphics g) 
	{
		double hcanvas = (double)height; // use local copy in case it gets
		double wcanvas = (double)width;  // altered while we draw
        	double length = .005;		// distance between wires (m)
		double wideness = length;	// other dimension of crystal
		double thickness = 5e-5;	// thickness of crystal (m)
		double twis_L = twist_L*Math.PI/180;
		double twis_R  = twist_R*Math.PI/180;
		double t_L, t_R; 		// here, t means torque
                double YoungsMod = 900e9;	// in Pa
		double ShearMod = 500e9;	// in Pa 
		double x, y;
		double[] u = new double[2];
		double[] v = new double[2];
		double u0 = 0.05*wcanvas;
                double uS = 0.90*wcanvas/length;
		double v0 = hcanvas/2;
                double vS = uS*(hcanvas/wcanvas)*750;
                double xstep = length/100;
		u[1] = u0;
		v[1] = v0;

		// calculate torques from twists,
                // using only the shear contribution
		double wire_radius = 12.5e-6;		// in meters	
		double wire_length = .001; 		// in meters	
		double wire_shearMod = 150e9;		// in Pa 
		t_L = wire_shearMod * twis_L * wire_radius*wire_radius*wire_radius* 
			wire_radius * Math.PI/(2*wire_length);
		t_R = wire_shearMod * twis_R * wire_radius*wire_radius*wire_radius* 
			wire_radius * Math.PI/(2*wire_length);

		// add label, dots
		g.setColor(Color.black);
		g.drawString("5 mm", (int)(u0 + .1 * wcanvas), 
				(int)(hcanvas/1.11)); 
		g.drawString("5 µm", 8, (int)(hcanvas/1.3)); 
		g.fillOval((int)(u0 - 5), (int)v0, 10, 10);
		g.fillOval((int)(u0 + (uS*length) - 5), (int)v0, 10, 10);

		// calculate and draw curve
                double x1 = length;
		double y1 = x1 *
                           (t_L + t_R)/(length * ShearMod * wideness * thickness)
			  + 12 / (YoungsMod * wideness * 
				  thickness*thickness*thickness) *
                           ( x1*x1 * t_L/2  -  x1*x1*x1 * (t_L + t_R)/(length*6) );
		double highest = v0, lowest = v0;
		for (x = 0; x < length; x += xstep)
		{
			y = x *
                           (t_L + t_R)/(length * ShearMod * wideness * thickness)
			  + 12 / (YoungsMod * wideness * 
				  thickness*thickness*thickness) *
                           ( x*x * t_L/2  -  x*x*x * (t_L + t_R)/(length*6) );

			y = y - y1*(x/x1);
			u[0] = u[1];
			v[0] = v[1];
			u[1] = u0 + uS*x;
			v[1] = v0 + vS*y;
	
			if (v[1] < lowest)
			{
				lowest = v[1];
			}	
			if (v[1] > highest)
			{
				highest = v[1];
			}

			// kludge: lines are too thin to appear unless you draw
			// them with lots of small segments.  So we do the
			// scale this way.
			g.setColor(Color.black);
  			g.drawLine((int)u[0], (int)(hcanvas/1.1), 
				   (int)u[1], (int)(hcanvas/1.1));
  			g.drawLine(1, (int)(v0 + 2.5e-6*vS), 
				   1, (int)(v0 - 2.5e-6*vS));

			g.setColor(Color.red);
			g.drawLine( (int)u[0], (int)v[0],
                                    (int)u[1], (int)v[1] );
		}
System.out.println("Highest: " + (highest - v0)/vS + ", Lowest:" + 
	(lowest - v0)/vS);
	}
}