/** Daryl Rauhala
 * File: PlotCanvas.java
 * Henon Cavas with some flexability build in
 */

import java.awt.*;

public class PlotCanvas extends Canvas
{
 
 private static double maxDomX, maxDomY, minDomX, minDomY;
 private static double canHeight, canWidth, A, B;
 private double initX, initY;
 private int numPoints = 10000; 

   public PlotCanvas()
   {
      super();
   }

public void setToCanvasSize()
    {
    Rectangle temp = getBounds();
    canHeight = (double) temp.height;
    canWidth  = (double) temp.width;
    }

public void setHenonDefaults()
    {
     maxDomX = 2;
     maxDomY = 0.5;
     minDomX = -2;
     minDomY = -0.75;

     initX = 0.1;
     initY = 0.2;
     A = 1.4;
     B = 0.3;
     numPoints = 10000;
    }

public void setUserDomain(double maxx,double maxy,double minx,double miny)
    {
     maxDomX = maxx;
     maxDomY = maxy;
     minDomX = minx;
     minDomY = miny;
    }
    
public void setInitState(double x, double y)
    {
    initX = x;
    initY = y;
    }

 public void setIterations( int iterations )
  {
  numPoints = iterations;
  }

 public void setParametersAB( double a, double b )
  {
   A = a;
   B = b;
  }
 
/**
 * These mapping functions set according to the given
 * Canvas size and the X and Y domain.
 * The origin is in the bottom left corner.
 */

  private static int scaleY ( double y)
    {
     return (int) ( ((maxDomY - y)/(maxDomY-minDomY))*canHeight );
    }

  private static int scaleX ( double x)
    {
     return (int) ( ((x - minDomX)/(maxDomX-minDomX ))*canWidth );                                      
    }

/** 
 * Now do the inverse functions to convert a MouseClick to 
 * a number relative to the current Canvas size and scale
 */

   public double scaleMouseX( int x )
     {
      return (double) ( ( (double) x /canWidth)*(maxDomX - minDomX) + minDomX ) ; 
     }


   public double scaleMouseY( int y )
     {
      return (double) ( maxDomY - ( (double) y /canHeight)*(maxDomY - minDomY) ); 
     }

 private static void plotPoints(Graphics g, double x, double y, int iterations )
      
   {
      double xtemp;

      // these next lines draw the axis on the canvas for orientation
      g.drawLine(scaleX(0), scaleY(maxDomY), scaleX(0), scaleY(minDomY) );
      g.drawLine(scaleX(maxDomX), scaleY(0), scaleX(minDomX), scaleY(0) );

      for (int i = 1; i <= iterations; i++)
      {
         xtemp = 1.0 - A*x*x + y;
         y = B*x;
         x = xtemp;
         g.drawLine(scaleX(x), scaleY(y), scaleX(x), scaleY(y));
      }  
  }

   public void paint(Graphics g)
   {
      ZoomHandler.setClickNumber( true );   // reset the mouse click variable
      setToCanvasSize();          //set private variables to suit window size
      Rectangle r = getBounds();  // bounds for this canvas
      g.setColor(Color.black);
      plotPoints(g, initX, initY, numPoints);
      g.setColor(Color.red);
      g.drawRect(0, 0, r.width - 1, r.height - 1);
   }

}