Thread: Chessboard filling issue

Hi,

I'm trying to create an 8x8 chessboard using GeneralPath. I've been able to make the outline of the "matrix" itself, but I am having trouble filling it. I've tried filling it with both windingrules, so I guess my question is as follows: Is there any way I can make the board I've created using a path into one whole figure which allows me to fill every other square with the color black?

My code:

import java.awt.*;
import javax.swing.*;
import java.awt.geom.*;
 
public class chessBoard extends JApplet{
 
	public static void main (String []args) {
		JFrame frame = new JFrame();
		frame.setTitle("Chessboard");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		JApplet applet = new chessBoard();
		applet.init();
		frame.getContentPane().add(applet);
		frame.pack();
		frame.setVisible(true);
	}
 
	public void init() {
		JPanel panel = new chessBoardPanel();
		getContentPane().add(panel);
	}
}
 
class chessBoardPanel extends JPanel {
 
	public chessBoardPanel() {
		setBackground(Color.white);
		setPreferredSize(new Dimension(600, 400));
	}
 
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		Graphics2D g2 = (Graphics2D)g;
		GeneralPath path = new GeneralPath(GeneralPath.WIND_EVEN_ODD);
		g2.setColor(Color.black);
 
		int w = this.getWidth();
		int h = this.getHeight();
		float x0 = 0.1f*w;
		float y0 = 0.1f*h;
		float y = y0;
		float x = x0;
 
		path.reset();
		for (int i = 0; i <= 8; i++) {
			path.moveTo(x, y0);
			path.lineTo(x, h - y0);
			x += x0;
		}
		for (int i = 0; i <= 8; i++) {
			path.moveTo(x0, y);
			path.lineTo(w - x0, y);
			y += y0;
		}
		path.closePath();
		g2.draw(path);
	}
}

What I've done is created 9 lines vertically and horizonally, merging into an 8x8 matrix.

I've also tried adding this after I'm done drawing with"path":

AffineTransform tr = new AffineTransform();
		Shape pathshape;
		path.setWindingRule(GeneralPath.WIND_EVEN_ODD);
		pathshape = (Shape)tr.createTransformedShape(path);
		g2.draw(pathshape);

Current output:


Very grateful for any response.

Best regards
Ole Martin

A better way is to use a grid layout. Setup your JPanel to accept a 8*8 set of components, and then each component can be drawn separately.

public class GUI
{
     public static void main(String[] args)
     {
          JPanel board = new JPanel(new GridLayout(8,8,0,0));
          for (int i = 0; i < 63; i++)
          {
               if (i % 2 == 0)
               {
                    board.add(new Square(Color.black);
               }
               else
               {
                    board.add(new Square(Color.white);
               }
          }
          JFrame mainFrame = new JFrame(board);
          mainFrame.setDefaultCloseOperation(JFrame.CLOSE_ON_EXIT);
          mainFrame.setVisible(true);
     }
}

public class Square extends JComponent
{
     protected Color color;
 
     public Square(Color color)
     {
          this.color = color;
     }
 
     protected void PaintComponent(Graphics g)
     {
          super();
          Graphics ours = g.create(); // so we don't mess-up the original graphics
          ours.setColor(this.color);
          ours.fillRect(0,0,this.getWidth(), this.getHeight()); // I may have it drawing the wrong direction. If so, that's a simple fix
     }
}