[OpenJDK 2D-Dev] Displacement by one pixel if using setStroke

[Dr. Christoph Gille]

When using setStroke, the pixel is displaced by one position
I guess that it is a numeric rounding error in 2d.
The following program demonstrates the error and shows my workaround:
g.translate(0.001,0.001);




import java.awt.*;
import javax.swing.*;

/**
   You should see a dashed black-red rectangle.

   Without calling translate however, the dashed rectangle is displaced by one
   pixel.

   Starting
   java test.Topenjdk

   java -version
   java version "1.6.0_0"
   OpenJDK  Runtime Environment (build 1.6.0_0-b11)
   OpenJDK Client VM (build 1.6.0_0-b11, mixed mode, sharing)
*/
public final class Topenjdk extends JComponent {
    boolean bugfixed;
    public static void main(String argv[]) throws Exception {
        for(boolean withWorkaround : new boolean[]{true,false}) {
            final JFrame f=new JFrame(withWorkaround ? "With workaround" : "Bug: rectangles do not coincide ");
            final Topenjdk component=new Topenjdk();
            component.bugfixed=withWorkaround;
            f.getContentPane().add(component);
            f.setLocation(withWorkaround ? 20:0, withWorkaround ? 20:0);
            f.setSize(300,300);
            f.show();
        }
    }
    public void paintComponent(Graphics graphics) {
        final Graphics2D g=(Graphics2D)graphics;
        if (bugfixed) g.translate(0.001,0.001);
        g.setColor(Color.WHITE);
        g.fillRect(0,0,999,999);
        g.setColor(Color.BLACK);
        g.drawRect(10,10,100,100);
        g.setStroke(new BasicStroke(1f,BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND,1f,new float[]{12/3f, 12-12/3f},3));
        g.setColor(Color.RED);
        g.drawRect(10,10,100,100);
        if (bugfixed)  g.translate(-0.001,-0.001);
    }
}