Problems with ScrollPane's

Question

I have a ScrollPane
// Canvas
Canvas m_MapCanvas = new Canvas();
// ScrollPane
ScrollPane scrollPane1 = new ScrollPane(ScrollPane.SCROLLBARS_ALWAYS);
// add mouse listener's
addMouseMotionListener(this);
addMouseListener(this);
// Canvas init
m_MapCanvas.setBounds(0,0,512,512);
// Init
scrollPane1.setBounds(new Rectangle(MapPos.x, MapPos.y, 800, 600));
scrollPane1.getVAdjustable().setUnitIncrement( 32 );
scrollPane1.add(m_MapCanvas);
scrollPane1.addMouseListener(this);
scrollPane1.addMouseMotionListener(this);
// Add
contentPane.add(scrollPane1);Case 1:
I load an image file into a BufferedImage. After the file is loaded I set the size if the Canvas to the size of the BufferedImage, and draw this on m_MapCanvas. The m_Canvas still remains the same size in scrollPane1.
I set the size like this:
m_MapCanvas.setSize(l_iWidth, l_iHeight);Case 2:
I cant read the mouse position when the mouse is above the scrollPane
I get the mouse envent like this:
public void mouseMoved(MouseEvent e)
    mouseXpos = e.getX();
    mouseYpos = e.getY();
}

Answer 1

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import javax.imageio.ImageIO;
public class ScrollPaneTest
    ScrollableCanvas scrollableCanvas;
    public ScrollPaneTest()
        scrollableCanvas = new ScrollableCanvas(getImages());
        ScrollPane scrollPane = new ScrollPane();
        scrollPane.add(scrollableCanvas);
        Frame f = new Frame();
        f.addWindowListener(new WindowAdapter()
            public void windowClosing(WindowEvent e)
                System.exit(0);
        f.add(getImageController(), "North");
        f.add(scrollPane);
        f.add(getSizeController(), "South");
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    private BufferedImage[] getImages()
        String[] fileNames = {
            "barnowl.jpg", "timberwolf.jpg", "owls.jpg", "coyote.jpg"
        BufferedImage[] images = new BufferedImage[fileNames.length];
        for(int j = 0; j < images.length; j++)
            try
                URL url = getClass().getResource("images/" + fileNames[j]);
                images[j] = ImageIO.read(url);
            catch(MalformedURLException mue)
                System.err.println("url" + mue.getMessage());
            catch(IOException ioe)
                System.err.println("read: " + ioe.getMessage());
        return images;
    private Panel getImageController()
        Button next = new Button("next image");
        next.addActionListener(new ActionListener()
            public void actionPerformed(ActionEvent e)
                scrollableCanvas.moveAhead();
        Panel panel = new Panel();
        panel.add(next);
        return panel;
    private Panel getSizeController()
        final Button
            less = new Button("smaller canvas"),
            more = new Button("bigger canvas");
        ActionListener l = new ActionListener()
            int direction;
            public void actionPerformed(ActionEvent e)
                Button button = (Button)e.getSource();
                if(button == less)
                    direction = -1;
                if(button == more)
                    direction = 1;
                scrollableCanvas.changeSize(direction);
        less.addActionListener(l);
        more.addActionListener(l);
        Panel panel = new Panel();
        panel.add(less);
        panel.add(more);
        return panel;
    public static void main(String[] args)
        new ScrollPaneTest();
class ScrollableCanvas extends Canvas
    BufferedImage[] images;
    int index;
    Dimension size;
    public ScrollableCanvas(BufferedImage[] images)
        this.images = images;
        index = 0;
        size = new Dimension(images[index].getWidth(), images[index].getHeight());
    public void paint(Graphics g)
        super.paint(g);
        int w = getWidth();
        int h = getHeight();
        int imageWidth = images[index].getWidth();
        int imageHeight = images[index].getHeight();
        int x = (w - imageWidth)/2;
        int y = (h - imageHeight)/2;
        g.drawImage(images[index], x, y, this);
    public Dimension getPreferredSize()
        return size;
    public void moveAhead()
        index = (index + 1) % images.length;
        size.width  = images[index].getWidth();
        size.height = images[index].getHeight();
        invalidate();             // mark this (Canvas) invalid
        getParent().validate();   // ask scrollPane to validate its child
        repaint();
    public void changeSize(int direction)
        size.width  = size.width  + (int)(direction * 0.1 * size.width);
        size.height = size.height + (int)(direction * 0.1 * size.height);
        invalidate();
        getParent().validate();
}