Unwanted space within an extended JPanel

Question

Hello JDC
I subclass the Jpanel and I draw an image inside. The problem is that I receive unwanted empty space in the canvas bounds. I tried to set the mini,maxi and preferred size of both the jframe and the canvas but its doesnt help.
public class ImageCanvas extends JPanel{
  static Image thisImg=null;
  static URL url=null;
  static Toolkit tool=null;
  public static final String DEFAULTADDRESS = "http://127.0.0.1/image/def.gif";
  public static final  boolean PRINTLN=true;
  public  static void p(String out){
    if(PRINTLN)
      System.out.println(out);
  // constructs a
  public ImageCanvas(String filepath){
     setLayout(new BorderLayout());
     try{
      url = new URL(filepath);
    }catch(Exception e){
      System.out.println("problem with creating url :" + e.toString());
    thisImg = Toolkit.getDefaultToolkit().getImage(url);
  public ImageCanvas(){
    try{
      url = new URL(DEFAULTADDRESS);
    }catch(Exception e){
      System.out.println("problem with creating url :" + e.toString());
    thisImg = Toolkit.getDefaultToolkit().getImage(url);
    repaint();
  public void setPic(Image x){
    //System.out.println("ImageCanvas > setPit(Image) invoked");
    thisImg = x;
    repaint();
  public static Image makeImage(String path){
    try{
      url = new URL(path);
    }catch(Exception e){
      System.out.println("problem with creating url :" + e.toString());
    Image img = Toolkit.getDefaultToolkit().getImage(url);
    return img;
  public void paintComponent(Graphics g){
    g.drawImage(thisImg,0,0,this);
public void update(Graphics g){
    paint(g);
  public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.getContentPane().add(new ImageCanvas());
      frame.addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
          System.exit(0);
    frame.pack();
    frame.setVisible(true);
}the image dimension 100x100
Any replies will by imprecated
Shay Gaghe

Answer 1

You could try using JLabel instead of subclassing JPanel. Just set the label's icon and don't set any text.
I also agree that GridBagLayout is the most useful layout. When I was new to Java programming it was the most confusing. In order to do complicated graphical interfaces I use to have to use a lot of nested panels with different layouts. Even then I had problems because I couldn't specify exactly which component should expand etc. Now, two years later and after becoming a Sun certified programmer for the Java 2 platform, I use GridBagLayouts almost always and it give me the most flexibility. It allows me to make some really professional gui programs. I recommend spending some time getting used to using GridBagLayout more.