How to find a point lies inside circle

Question

Hi,
How do I find a point (x,y) is lies inside a circle? I trying to do a small shooting game.
If the user clicks inside the circle they get a point. I am using the Pythagoras theorem to achieve this. But I can't.
Please advice me.
Here is my code
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Shoot extends JFrame implements MouseListener, MouseMotionListener
    private int winWidth = 300;
    private int winHeight = 300;
    private MyCanvas canvas = null;
    private int ballX = 50;
    private int ballY = 50;
    private int ballW = 50;
    private int ballH = 50;
    private int ballR = ballW / 2;
    private int curX = 0;
    private int curY = 0;
    private int left = 0;
    private int top = 0;
    public Shoot()
        Cursor c = new Cursor(Cursor.CROSSHAIR_CURSOR);
        this.setCursor(c);
        canvas = new MyCanvas();
        packIt();
        left = getInsets().left;
        top = getInsets().top;
    private void packIt()
        setTitle("My first game!");
        setPreferredSize(new Dimension(winWidth, winHeight));
        setSize(new Dimension(winWidth, winHeight));
        setContentPane(canvas);
        addMouseListener(this);
        addMouseMotionListener(this);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //setUndecorated(true);
        setLocation(300, 0);
        setVisible(true);
    public void mouseClicked(MouseEvent e)
        int x = e.getX() - left - ballX;
        int y = e.getY() - top - ballY;
        int r = ballR;
        System.out.println("x :" + x + "\ty :" + y);
        //Trying to implememt Pythagoras theorem. But I am missing something.
        System.out.println(((x * x) + (y * y)) + "\t=\t" + (r * r));
        System.out.println();
    public void mousePressed(MouseEvent e)
    public void mouseReleased(MouseEvent e)
    public void mouseEntered(MouseEvent e)
    public void mouseExited(MouseEvent e)
    public void mouseDragged(MouseEvent e)
    public void mouseMoved(MouseEvent e)
        curX = e.getX() - left;
        curY = e.getY() - top;
        canvas.repaint();
    private class MyCanvas extends JPanel
        public MyCanvas()
            setBackground(Color.BLACK);
            setBorder(BorderFactory.createLineBorder(Color.yellow));
        public void paintComponent(Graphics g)
            super.paintComponent(g);
            g.setColor(Color.WHITE);
            g.drawString("x :" + curX, 10, 20);
            g.drawString("y :" + curY, 10, 30);
            g.setColor(Color.RED);
            g.fillOval(ballX, ballY, ballW, ballH);
    public static void main(String[] asd)
        new Shoot();
}

Answer 1

public boolean isPointInCircle(){
    double x= circle.getWidth/2.0+circle.getX();
    double y= circle.getHeight/2.0+circle.getY();
    double distance=getDistance(x,y,pointX,PointY);
    return (distance<= circle.getWidth/2.0); //if the distance from the point to the center of the circle is less than the radius of the circle return true
double getDistance(double x1, double y1, double x2, double y2){
    return math.sqrt((x1-x2)(x1-x2) + (y1-y2)(y1-y2));
}Edited by: ghostbust555 on Jan 23, 2011 3:20 PM