Concurrent Programming with Java
Lab Manual, Version 1.0, F. Astha Ekadiyanto, 2002.

[Contents] [Next] [Previous]

Lab 3: Building Applets - Graphical representation

Adding draw(Graphics) method in HexCell Class

Similar to the process in defining draw(Graphics) method in the CircleCell, the declaration of HexCell Class should change into:

public class HexCell extends Cell implements Visualization

Then add a new method called draw(Graphics g) inside the Class definition. This time we will use the drawPolygon(Polygon) method.
But, before we could call the drawPolygon(Polygon) method, we must first create a Polygon Object that represent the HexCell Shape.

We can create a Hexagonal Polygon just by adding the six corner points into the Polygon Object. Of course, things would be easier if we could define a looping process for it.

 Polygon polygon = new Polygon(); 
 for( int i=0; i<6;i++) 
 {
   int x1 = (int) ( x + r * Math.cos(i*Math.PI/3));
   int y1 = (int) ( y + r * Math.sin(i*Math.PI/3)); 
   polygon.addPoint(x1,y1);
 }

After that, drawing Polygon should be very simple

 g.drawPolygon(polygon);

The complete implementation in Java is shown below.

import java.lang.Math;
import java.awt.Graphics;
import java.awt.Polygon;
public class HexCell extends Cell implements Visualization
{

     // . . . all other code of the original HexCell Class
       
     public void draw(Graphics g)
     {
        double x = getX();
        double y = getY();
        double r = getR();             
        Polygon polygon = new Polygon();        
        for( int i=0; i<6;i++) {
            int x1 = (int) ( x + r * Math.cos(i*Math.PI/3));
            int y1 = (int) ( y + r * Math.sin(i*Math.PI/3));            
            polygon.addPoint(x1,y1);
        }
        g.drawPolygon(polygon);
     } 
}

 

[Contents] [Next] [Previous]