Name: rm29839 Date: 03/31/98


/////////////////////////////////////////////////////////////////////////////////////////////////
//
// When the size of the component inside the JScrollPane is
// more than that of the JScrollPane itself, any painting done
// by the component paints over other components in the
// frame (the frame that contains the scroll pane and some other
// components). This happens only when painting is done
// using a Graphics objects returned by getGraphics(). This
// problem does not occur when the same painting is done
// using the Graphics object given to paint() function.
//
// Here's the source code in its entirety - run it and see for yourself.
/////////////////////////////////////////////////////////////////////////////////////////////////

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import com.sun.java.swing.*;

public class Test extends JFrame
{
    Test(String s)
    {
        super(s);
    }

    static public void main (String []args)
    {
        Test tst = new Test("Test Application");
        tst.getContentPane().setLayout(new BorderLayout());
        tst.getContentPane().add("East", new JButton ("East"));
        tst.getContentPane().add("West", new JButton ("West"));
        tst.getContentPane().add("North", new JButton ("North"));
        tst.getContentPane().add("South", new JButton ("South"));
        tst.getContentPane().add(new MyScrollPane());
        tst.setSize(640, 480);
        tst.show();
    }
}

class MyScrollPane extends JScrollPane
{
    MyScrollPane()
    {
super (new Contained());
    }
}

class Contained extends JComponent implements MouseMotionListener
{
Contained()
{
addMouseMotionListener(this);
}
    public Dimension getMaximumSize()
    {
return new Dimension(1500, 1500);
    }
    public Dimension getMinimumSize()
    {
return new Dimension(1500, 1500);
    }
    public Dimension getPreferredSize()
    {
return new Dimension(1500, 1500);
    }
public void mouseDragged(MouseEvent e)
{
Graphics g;
g = getGraphics();
Point point;
point = e.getPoint();
// repaint();
display_mouse_coordinates(g, point);
}
public void mouseMoved(MouseEvent e)
{
Graphics g;
g = getGraphics();
Point point;
point = e.getPoint();
// repaint();
display_mouse_coordinates(g, point);
}
void display_mouse_coordinates(Graphics g, Point point)
{
        String s;
s = point.x + ", " + point.y;

        Dimension dimWin = getSize();
        Insets insFrame = getInsets();
        int nWinWidth = dimWin.width - (insFrame.left + insFrame.right);
        int nWinHeight = dimWin.height - (insFrame.top + insFrame.bottom);

g.setColor(Color.white);
        g.fillRect(0, 0, nWinWidth, nWinHeight);
g.setColor(Color.black);
g.drawString(s, point.x, point.y);
}
}
(Review ID: 26665)
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