how to draw rectangle on java applet using mouse drag event

Question

i am using java. i want to draw rectangle based on mousedrag event. if user dragging the mouse, then the rectangle on the applet should increase or decrease basing on current mo

Answer 1

My question was about create a select rectangle invert mouse click position, but, in the end I got make this with this method:

...     //to set the selection area
    private int iniSelX;
    private int iniSelY;
    private int endSelX;
    private int endSelY;

    private JPanel myJPanel = new JPanel() {

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.setColor(Color.WHITE);
            g.fillRect(0, 0, this.getWidth(), this.getHeight());

            g.setColor(Color.red);
            g.drawLine(260, 5, 260, 260);

            g.setColor(Color.BLUE);

            //verify if go draw the rectangle
            if (iniSelX != 0 || endSelX != 0) {
                boolean revertX = iniSelX < endSelX;
                boolean revertY = iniSelY < endSelY;

                //Simple way
                //g.drawRect(iniSelX, iniSelY, endSelX - iniSelX, endSelY - iniSelY);

                //reverse way
                g.drawRect(revertX ? iniSelX : endSelX, revertY ? iniSelY : endSelY,
                        revertX ? endSelX - iniSelX : iniSelX - endSelX, revertY ? endSelY - iniSelY : iniSelY - endSelY);
            }
        }
    }; ...
        addMouseMotionListener(new MouseMotionListener() {

            @Override
            public void mouseDragged(MouseEvent m) {
                //update selection area
                endSelX = m.getX();
                endSelY = m.getY();

                repaint();
            }

            @Override
            public void mouseMoved(MouseEvent m) {
                repaint();
            }
        });

        addMouseListener(new MouseListener() {

 ...
            @Override
            public void mousePressed(MouseEvent e) {
               //start  drawing the selection
                iniSelX = e.getX() - 15;
                iniSelY = e.getY() - 20;
            }

            @Override
            public void mouseReleased(MouseEvent e) {
                //start  drawing the selection
                iniSelX = 0;
                iniSelY = 0;
                endSelX = 0;
                endSelY = 0;
            }

...
        });

    }

    public void log() {
        System.out.println("iniSelX" + iniSelX);
        System.out.println("iniSelY" + iniSelY);
        System.out.println("endSelX" + endSelX);
        System.out.println("endSelY" + endSelY);
    } ...

I hope this is useful.