import java.awt.*;


/** class to draw the graphs from bd.java

    @author Jeremy harris
*/

public class bdCanvas extends Canvas
{
  public final int X1 = 50;
  public final int Y1 = 50;
  public final int X2 = 350;
  public final int Y2 = 350;
  public final int BY = Y2+15;
  public final int L1X = X1-12;
  public final int L2X = X1-20;
  public final int HORZAMT = 30;
  public final int VERTAMT = 10;

  private Point[] mypnts;
  private int[] mypops;
  private boolean points = false;
  private boolean axis = true;
  
  public bdCanvas()
    /** constructor for the canvas to be used
	to draw the graphs on, initializes variables and 
	sets parameters
    */
    {
      setBackground(Color.white);
      setForeground(Color.black);
      setSize(400,410);
      mypops = new int[10];
      mypnts = new Point[10];
    }

  public void Ok()
    /** sets test value to true, indicating that the 
	sim has been run and points can now be plotted
    */
    {
      points = true;
    }

  public void Plot(int[] pops)
    /** plots a set of points on the graph

	@param pops the array of values to be plotted
    */
    {
      mypops = pops;
      repaint();
    }

  public void paint(Graphics g)
    /** overloaded method of Canvas class, does all 
	drawing on the graph
    */
    {
      g.setColor(Color.black);

      if(axis)
	{
	  g.drawLine(X1,Y1,X1,Y2);
	  g.drawLine(X1,Y2,X2,Y2);	  
	  g.drawString("0",X1,BY);

	  /* draw x-axis values */
	  int x = X1+30;
	  for(int xaxis=10;xaxis<=100;xaxis+=10)
	    {
	      g.drawString(String.valueOf(xaxis),x-5,BY);
	      x += 30;
	    }
	  
	  /* draw y-axis values */
	  int y = Y2-20;
	  for(int yaxis=2;yaxis<=8;yaxis+=2)
	    {
	      g.drawString(String.valueOf(yaxis),L1X,y+5);
	      y -= 20;
	    }
	  for(int yaxis=10;yaxis<=30;yaxis+=2)
	    {
	      g.drawString(String.valueOf(yaxis),L2X,y+5);
	      y -= 20;
	    }

	  /* set labels */
	  g.drawString("y-axis: time, x-axis: population",X1+55,BY+30);
	}
      
      /* draw points and lines*/
      if(points)
	{
	  int x=X1;
	  for(int k=0;k<10;k++)
	    {
	      mypnts[k] = new Point(x,Y2-VERTAMT*mypops[k]);
	      g.fillRect(x,Y2-VERTAMT*mypops[k],2,2);
	      x += 30;
	    }
	  for(int k=0;k<9;k++)
	    {
	      g.drawLine(mypnts[k].x,mypnts[k].y,mypnts[k+1].x,mypnts[k+1].y);
	    }
	}
    }
}