Problems with Overlay Layout - can anyone spot something wrong/missing?

Question

Hi folks, I'm developing a tool that allows you to draw rectangles around objects on an image. The rectangles are then saved, and you can move between images. For some reason, though my rectangles are not drawing on the panel. I am using the Overlay Layout. Can anyone spot what I'm doing wrong? (The TopPanel canvas appears to be there, as it's taking input from the mouse - the problem is simply that the red rectangles are not drawing on the panel). Please help!!
So you know, there is a JFrame in another class which adds an instance of the ObjectMarker panel to it. It also provides buttons for using the next and previous Image methods.
Any other general advice is appreciated too.
* Object_Marker.java
* Created on 07 April 2008, 15:38
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import javax.imageio.ImageIO;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.OverlayLayout;
import javax.swing.event.MouseInputAdapter;
* @author Eric
public class ObjectMarker extends javax.swing.JPanel {
     private static final long serialVersionUID = 6574271353772129556L;
     File directory;
     String directory_path;
     Font big = new Font("SansSerif", Font.BOLD, 18);
     List<File> file_list = Collections.synchronizedList(new LinkedList<File>());
     String[] filetypes = { "jpeg", "jpg", "gif", "bmp", "tif", "tiff", "png" };
     // This Hashmap contains List of Rectangles, allowing me to link images to collections of rectangles through the value 'index'.
     public static HashMap<Integer, List<Rectangle>> collection = new HashMap<Integer, List<Rectangle>>();
     BufferedImage currentImage;
     Thread thread;
     Integer index = 0;
     OverlayLayout overlay;
     private TopPanel top;
     private JPanel pictureFrame;
     String newline = System.getProperty("line.separator");
      * Creates new form Object_Marker
      * @throws IOException
     public ObjectMarker(File directory) {
          System.out.println("Got in...");
          this.directory = directory;
          File[] temp = directory.listFiles();
          directory_path = directory.getPath();
          // Add all the image files in the directory to the linked list for easy
          // iteration.
          for (File file : temp) {
               if (isImage(file)) {
                    file_list.add(file);
          initComponents();
          try {
               currentImage = ImageIO.read(file_list.get(index));
          } catch (IOException e) {
               System.out.println("There was a problem loading the image.");
          // 55 pixels offsets the height of the JMenuBar and the title bar
          // which are included in the size of the JFrame.
          this.setSize(currentImage.getWidth(), currentImage.getHeight() + 55);
     public String getImageList() {
          // Allows me to build the string gradually.
          StringBuffer list = new StringBuffer();
          list.append("Image files found in directory: \n\n");
          for (int i = 0; i < file_list.size(); i++) {
               list.append((((File) file_list.get(i))).getName() + "\n");
          return list.toString();
     private void initComponents() {
          top = new TopPanel();
          pictureFrame = new javax.swing.JPanel();
          OverlayLayout ol = new OverlayLayout(this);
          this.setLayout(ol);
          this.add(top);
          this.add(pictureFrame);
      * private void initComponents() {
      * javax.swing.GroupLayout pictureFrameLayout = new
      * javax.swing.GroupLayout(pictureFrame);
      * pictureFrame.setLayout(pictureFrameLayout);
      * pictureFrameLayout.setHorizontalGroup(
      * pictureFrameLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
      * .addGap(0, 497, Short.MAX_VALUE) ); pictureFrameLayout.setVerticalGroup(
      * pictureFrameLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
      * .addGap(0, 394, Short.MAX_VALUE) );
      * javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
      * this.setLayout(layout); layout.setHorizontalGroup(
      * layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
      * .addComponent(pictureFrame, javax.swing.GroupLayout.DEFAULT_SIZE,
      * javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) );
      * layout.setVerticalGroup(
      * layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
      * .addComponent(pictureFrame, javax.swing.GroupLayout.DEFAULT_SIZE,
      * javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) ); }
      * This function returns the extension of a given file, for example "jpg" or
      * "gif"
      * @param f
      *            The file to examine
      * @return String containing extension
     public static String getExtension(File f) {
          String ext = null;
          String s = f.getName();
          int i = s.lastIndexOf('.');
          if (i > 0 && i < s.length() - 1) {
               ext = s.substring(i + 1).toLowerCase();
          } else {
               ext = "";
          return ext;
     public String getDetails() {
          saveRectangles();
          StringBuffer sb = new StringBuffer();
          for (int i = 0; i < file_list.size(); i++) {
               try{
               int count = collection.get(i).size();
               if (count > 0) {
                    sb.append(file_list.get(i).getPath() + " "); // Add the
                    // filename of
                    // the file
                    sb.append(count + " "); // Add the number of rectangles
                    for (int j = 0; j < collection.get(i).size(); j++) {
                         Rectangle current = collection.get(i).get(j);
                         String coordinates = (int) current.getMinX() + " "
                                   + (int) current.getMinY() + " ";
                         String size = ((int) current.getMaxX() - (int) current
                                   .getMinX())
                                   + " "
                                   + ((int) current.getMaxY() - (int) current
                                             .getMinY()) + " ";
                         String result = coordinates + size;
                         sb.append(result);
                    sb.append(newline);
               } catch (NullPointerException e){
                    // Do nothing.  "int count = collection.get(i).size();"
                    // will try to over count.
          return sb.toString();
     private boolean isImage(File f) {
          List<String> list = Arrays.asList(filetypes);
          String extension = getExtension(f);
          if (list.contains(extension)) {
               return true;
          return false;
     /** Draw the image on the panel. * */
     public void paint(Graphics g) {
          if (currentImage == null) {
               g.drawString("No image to display!", 300, 240);
          } else {
               // Draw the image
               g.drawImage(currentImage, 0, 0, this);
               // Write the index
               g.setFont(big);
               g.drawString(index + 1 + "/" + file_list.size(), 10, 25);
     public void nextImage() throws IOException {
          if (index < file_list.size() - 1) {
               printOutContents();
               System.out.println("Index: " + index);
               saveRectangles();
               index++;
               currentImage = ImageIO.read(file_list.get(index));
               this
                         .setSize(currentImage.getWidth(),
                                   currentImage.getHeight() + 55);
               top.setSize(this.getSize());
               top.rectangle_list.clear();
               if (collection.size() > index) {
                    loadRectangles();
               repaint();
     private void saveRectangles() {
          // If the current image's rectangles have not been changed, don't do
          // anything.
          if (collection.containsKey(index)) {
               System.out.println("Removing Index: " + index);
               collection.remove(index);
          collection.put(index, top.getRectangleList());
          System.out.println("We just saved " + collection.get(index).size()
                    + " rectangles");
          System.out.println("They were saved in HashMap Location " + index);
          System.out.println("Proof: ");
          List<Rectangle> temp = collection.get(index);
          for (int i = 0; i < temp.size(); i++) {
               System.out.println("Rectangle " + (i + 1) + ": " + temp.get(i));
          // If the rectangle list has changed, set the list the current index
          // as the new list.
     private void loadRectangles() {
          System.out.println("We just loaded index " + index
                    + " into temporary memory.");
          System.out.println("Proof: ");
          List<Rectangle> temp = collection.get(index);
          top.rectangle_list = collection.get(index);
          for (int i = 0; i < temp.size(); i++) {
               System.out.println("Rectangle " + (i + 1) + ": " + temp.get(i));
     private void printOutContents() {
          System.out.println();
          System.out.println("Contents printout...");
          for (int i = 0; i < collection.size(); i++) {
               for (Rectangle r : collection.get(i)) {
                    System.out.println("In collection index: " + i + " Rectangle "
                              + r.toString());
          System.out.println();
     public void previousImage() throws IOException {
          if (index >= 1) {
               printOutContents();
               System.out.println("Index: " + index);
               saveRectangles();
               index--;
               currentImage = ImageIO.read(file_list.get(index));
               this
                         .setSize(currentImage.getWidth(),
                                   currentImage.getHeight() + 55);
               top.setSize(this.getSize());
               top.rectangle_list.clear();
               if (index >= 0) {
                    loadRectangles();
               repaint();
     public void removeLastRectangle() {
          // This method removes the most recent rectangle added.
          try {
               int length = collection.get(index).size();
               collection.get(index).remove(length - 1);
          } catch (NullPointerException e) {
               try {
                    top.rectangle_list.remove(top.rectangle_list.size() - 1);
               } catch (IndexOutOfBoundsException ioobe) {
                    JOptionPane.showMessageDialog(this, "Cannot undo any more!");
* Class developed from SSCCE found on Java forum:
* http://forum.java.sun.com/thread.jspa?threadID=647074&messageID=3817479
* @author 74philip
class TopPanel extends JPanel {
     List<Rectangle> rectangle_list;
     private static final long serialVersionUID = 6208367976334130998L;
     Point loc;
     int width, height, arcRadius;
     Rectangle temp; // for mouse ops in TopRanger
     public TopPanel() {
          setOpaque(false);
          rectangle_list = Collections
                    .synchronizedList(new LinkedList<Rectangle>());
          TopRanger ranger = new TopRanger(this);
          addMouseListener(ranger);
          addMouseMotionListener(ranger);
     public List<Rectangle> getRectangleList() {
          List<Rectangle> temporary = Collections
                    .synchronizedList(new LinkedList<Rectangle>());
          temporary.addAll(rectangle_list);
          return temporary;
     protected void paintComponent(Graphics g) {
          super.paintComponent(g);
          Graphics2D g2 = (Graphics2D) g;
          g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                    RenderingHints.VALUE_ANTIALIAS_ON);
          g2.setPaint(Color.red);
          // Draw all the rectangles in the rectangle list.
          for (int i = 0; i < rectangle_list.size(); i++) {
               g2.drawRect(rectangle_list.get(i).x, rectangle_list.get(i).y,
                         rectangle_list.get(i).width, rectangle_list.get(i).height);
          if (temp != null) {
               g2.draw(temp);
     public void loadRectangleList(List<Rectangle> list) {
          rectangle_list.addAll(list);
     public void addRectangle(Rectangle r) {
          rectangle_list.add(r);
class TopRanger extends MouseInputAdapter {
     TopPanel top;
     Point offset;
     boolean dragging;
     public TopRanger(TopPanel top) {
          this.top = top;
          dragging = false;
     public void mousePressed(MouseEvent e) {
          Point p = e.getPoint();
          top.temp = new Rectangle(p, new Dimension(0, 0));
          offset = new Point();
          dragging = true;
          top.repaint();
     public void mouseReleased(MouseEvent e) {
          dragging = false;
          // update top.r
          System.out.println(top.getRectangleList().size() + ": Object added: "
                    + top.temp.toString());
          top.addRectangle(top.temp);
          top.repaint();
     public void mouseDragged(MouseEvent e) {
          if (dragging) {
               top.temp.setBounds(top.temp.x, top.temp.y, e.getX() - top.temp.x, e
                         .getY()
                         - top.temp.y);
               top.repaint();
}Regards,
Eric

Answer 1

Alright so I fixed it! I created a new class called BottomPanel extends JPanel, which I then gave the responsibility of drawing the image. I gave it an update method which took the details of the currentImage and displayed it on the screen.
If anybody's interested I also discovered/solved a problem with my mouseListener - I couldn't drag backwards. I fixed this by adding tests looking for negative widths and heights. I compensated accordingly by reseting the rectangle origin to e.getX(), e.getY() and by setting the to original_origin.x - e.getX() and original_origin.y - e.getY().
No problem!