Java AWT / swing “include” and “intersect” methods do not work properly

I tried to teach myself some Java AWT and simple graphics, but it was difficult to use the contains and intersects methods

The problem is that it seems to detect a collision of several pixels from the mouse click position and the actual shape

GameDemo. java

package uk.co.mhayward.games.sand@R_863_2419@;

import java.awt.Basicstroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Polygon;
import java.awt.Shape;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class GameDemo extends JFrame {

    GamePanel gamePanel = new GamePanel();

    public static void main(String[] args) {
        new GameDemo();
    }

    public GameDemo() {
        super("click me");
        this.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
        this.add(gamePanel);
        this.setSize(200,200);

        this.setVisible(true);
        this.addMouseListener(new MouseListener() {
            public void mouseClicked(MouseEvent e) {}

            public void mousePressed(MouseEvent e) {
                System.out.println(e.getPoint().toString());
                if (gamePanel.shape.contains(e.getPoint())) {
                    System.out.println("IN");
                } else {
                    System.out.println("out");
                }
            }

            public void mouseReleased(MouseEvent e) {}

            public void mouseEntered(MouseEvent e) {}

            public void mouseExited(MouseEvent e) {}
        });
    }

    public class GamePanel extends JPanel {

        Shape shape = new RegularPolygon(100,100,6,0);

        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);

            Graphics2D g2d = (Graphics2D) g;

            g2d.setstroke(new Basicstroke(1));
            g2d.setPaint(Color.WHITE);
            g2d.fill(shape);
            g2d.setPaint(Color.BLACK);
            g2d.draw(shape);
        }
    }

    public static class RegularPolygon extends Polygon {
        private static final long serialVersionUID = 8828151557263250246L;

        /**
         * @param x
         * @param y
         * @param r
         * @param vertexCount
         */
        public RegularPolygon(int x,int y,int r,int vertexCount) {
            this(x,y,r,vertexCount,0);
        }

        /**
         * @param x
         * @param y
         * @param r
         * @param vertexCount
         * @param startAngle
         *            360deg = PI
         */
        public RegularPolygon(int x,int vertexCount,double startAngle) {
            super(getXCoordinates(x,startAngle),getYCoordinates(x,vertexCount);
        }

        protected static int[] getXCoordinates(int x,double startAngle) {
            int res[] = new int[vertexCount];
            double addAngle = 2 * Math.PI / vertexCount;
            double angle = startAngle;
            for (int i = 0; i < vertexCount; i++) {
                res[i] = (int) Math.round(r * Math.cos(angle)) + x;
                angle += addAngle;
            }
            return res;
        }

        protected static int[] getYCoordinates(int x,double startAngle) {
            int res[] = new int[vertexCount];
            double addAngle = 2 * Math.PI / vertexCount;
            double angle = startAngle;
            for (int i = 0; i < vertexCount; i++) {
                res[i] = (int) Math.round(r * Math.sin(angle)) + y;
                angle += addAngle;
            }
            return res;
        }
    }
}

EDITS

04 / Jan / 12 – change the covering paint (g) to paintcomponent (g) – collision is still not detected correctly 05 / Jan / 12 – created an sscce to prove the problem more easily

Solution

Listen on the panel instead of JFrame The offset you see comes from the title bar