menus.java

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            if (System.getProperty("mrj.version") != null)
               commandKey = "meta ";
         }
         catch (SecurityException e) {
         }
      }
      return KeyStroke.getKeyStroke(commandKey + description);
   }
   
   
   /**
    * A convenience method that breaks up a string into tokens, where
    * the tokens are substrings seprated by specified delimiters.
    * For example, explode("ab,cde,f,ghij", ",") produces an array
    * of the four substrings "ab"  "cde"  "f"  "ghi".
    */
   private String[] explode(String str, String separators) {
      StringTokenizer tokenizer = new StringTokenizer(str, separators);
      int ct = tokenizer.countTokens();
      String[] tokens = new String[ct];
      for (int i = 0; i < ct; i++)
         tokens[i] = tokenizer.nextToken();
      return tokens;
   }
   
   
   /**
    * Enables/Disables some menu items, based on the status of the MandelbrotDisplay.
    * This method is called by a listener that listens for property change events
    * from the display.
    * @param status is probably either "working" or "ready".  Working means that
    *   a computation is in progress in the display.  The save commands, the
    *   entire MaxIterations menu,and the Set Limits and Set Image Size commands
    *   are disabled during computations.  There is a small posility that the 
    *   program will not have enough memory to create the image; Set Image Size
    *   would be enabled in this case because changing the image size might fix
    *   the problem.
    */
   private void newDisplayStatus(Object status) {
      boolean ready = status.equals(MandelbrotDisplay.STATUS_READY);
      boolean outofmem = status.equals(MandelbrotDisplay.STATUS_OUT_OF_MEMORY);
      saveImage.setEnabled(ready);
      saveParams.setEnabled(ready);
      openParams.setEnabled(ready);
      setLimits.setEnabled(ready);
      setImageSize.setEnabled(ready || outofmem);
      maxIterationsManager.setEnabled(ready || outofmem);
   }
   
   
   /**
    * A little utility method that makes strings out of the xy-limits on the display,
    * where the lengths of the strings is adjusted depending on the distance between
    * xmax and xmin.  The idea is to try to avoid more digits after the decimal
    * points than makes sense.  If it succeeds the coordinates that are shown for xmin
    * and xmax should differ only in their last four or five digits and the same should
    * also be true for ymin and ymax.
    * @return An array of 4 strings representing the values of xmin, xmax, ymin, ymax.
    */
   private String[] makeScaledLimitStrings() {
      double xmin = owner.getDisplay().getXmin();
      double xmax = owner.getDisplay().getXmax();
      double ymin = owner.getDisplay().getYmin();
      double ymax = owner.getDisplay().getYmax();
      double diff = xmax - xmin;
      if (diff == 0)
         return new String[] { ""+xmin, ""+xmax, ""+ymin, ""+ymax };
      int scale = 4;
      if (diff > 0) {
         while (diff < 1) {
            scale++;
            diff *= 10;
         }
      }
      String fmt = "%1." + scale + "f";
      String[] str = new String[4];
      str[0] = String.format(fmt,xmin);
      str[1] = String.format(fmt,xmax);
      str[2] = String.format(fmt,ymin);
      str[3] = String.format(fmt,ymax);
      return str;
   }
   
   // ------ The rest of the file defines Actions and nested classes that implement commands -------
   
   
   private Action saveParams = new AbstractAction(I18n.tr("command.save")) {
         // Saves current setting in an XML format file.
      public void actionPerformed(ActionEvent evt) {
         if (fileDialog == null)
            fileDialog = new JFileChooser();
         File selectedFile = new File(I18n.tr("files.saveparams.defaultFileName"));
         fileDialog.setSelectedFile(selectedFile); 
         fileDialog.setDialogTitle(I18n.tr("files.saveparams.title"));
         int option = fileDialog.showSaveDialog(owner);
         if (option != JFileChooser.APPROVE_OPTION)
            return;  // User canceled or clicked the dialog's close box.
         selectedFile = fileDialog.getSelectedFile();
         if (selectedFile.exists()) {  // Ask the user whether to replace the file.
            int response = JOptionPane.showConfirmDialog( owner,
                  I18n.tr("files.fileexists",selectedFile.getName()),
                  I18n.tr("files.confirmsave.title"),
                  JOptionPane.YES_NO_OPTION, 
                  JOptionPane.WARNING_MESSAGE );
            if (response == JOptionPane.NO_OPTION)
               return;  // User does not want to replace the file.
         }
         PrintWriter out; 
         try {
            FileOutputStream stream = new FileOutputStream(selectedFile); 
            out = new PrintWriter( stream );
         }
         catch (Exception e) {
            JOptionPane.showMessageDialog(owner,
                  I18n.tr("files.saveparams.error.cannotOpen", 
                        selectedFile.getName(), e.toString()));
            return;
         }
         try {
            out.print(currentSettingsAsXML());
            out.close();
         }
         catch (Exception e) {
            JOptionPane.showMessageDialog(owner,
                  I18n.tr("files.saveparams.error.cannotWrite", 
                        selectedFile.getName(), e.toString()));
         }   
      }
   };
   
   
   private Action openParams = new AbstractAction(I18n.tr("command.open")) {
          // Loads settings from an XML file of the form that is saved by the Save Params command.
      public void actionPerformed(ActionEvent evt) {
         if (fileDialog == null)
            fileDialog = new JFileChooser();
         fileDialog.setDialogTitle(I18n.tr("files.openparams.title"));
         fileDialog.setSelectedFile(null);  // No file is initially selected.
         int option = fileDialog.showOpenDialog(owner);
         if (option != JFileChooser.APPROVE_OPTION)
            return;  // User canceled or clicked the dialog's close box.
         File selectedFile = fileDialog.getSelectedFile();
         Document xmldoc;
         try {
            DocumentBuilder docReader = DocumentBuilderFactory.newInstance().newDocumentBuilder();
            xmldoc = docReader.parse(selectedFile);
         }
         catch (Exception e) {
            JOptionPane.showMessageDialog(owner,
                  I18n.tr("files.openparams.error.notXML", 
                        selectedFile.getName(), e.toString()));
            return;
         }
         try {
            retrieveSettingsFromXML(xmldoc);
         }
         catch (Exception e) {
            JOptionPane.showMessageDialog(owner,
                  I18n.tr("files.openparams.error.notParamsFile", 
                        selectedFile.getName(), e.getMessage()));
         }   
      }
   };
   
   
   private Action saveImage = new AbstractAction(I18n.tr("command.saveImage")) {
         // Saves the current image as a file in PNG format.
      public void actionPerformed(ActionEvent evt) {
         if (fileDialog == null)      
            fileDialog = new JFileChooser();
         BufferedImage image;  // A copy of the sketch will be drawn here.
         image = owner.getDisplay().getImage();
         if (image == null) {
            JOptionPane.showMessageDialog(owner,I18n.tr("files.saveimage.noImage"));
            return;
         }
         fileDialog.setSelectedFile(new File(I18n.tr("files.saveimage.defaultFileName"))); 
         fileDialog.setDialogTitle(I18n.tr("files.saveimage.title"));
         int option = fileDialog.showSaveDialog(owner);
         if (option != JFileChooser.APPROVE_OPTION)
            return;  // User canceled or clicked the dialog's close box.
         File selectedFile = fileDialog.getSelectedFile();
         if (selectedFile.exists()) {  // Ask the user whether to replace the file.
            int response = JOptionPane.showConfirmDialog( owner,
                  I18n.tr("files.fileexists",selectedFile.getName()),
                  I18n.tr("files.confirmsave.title"),
                  JOptionPane.YES_NO_OPTION, 
                  JOptionPane.WARNING_MESSAGE );
            if (response == JOptionPane.NO_OPTION)
               return;  // User does not want to replace the file.
         }
         try {
            boolean hasPNG = ImageIO.write(image,"PNG",selectedFile);
            if ( ! hasPNG )
               throw new Exception(I18n.tr("files.saveimage.noPNG"));
         }
         catch (Exception e) {
            JOptionPane.showMessageDialog(owner,
                  I18n.tr("files.saveimage.cantwrite", 
                        selectedFile.getName(), e.toString()));
         }   
      }
   };
   
   
   private Action close = new AbstractAction(I18n.tr("command.close")) {
         // Implement the Close or Quit command by disposing the frame.
      public void actionPerformed(ActionEvent evt) {
         frame.dispose();
      }
   };
   
   
   private Action defaultLimits = new AbstractAction(I18n.tr("command.defaultLimits")) {
         // Restores the default xy-limits on the MandelbrotDisplay.
      public void actionPerformed(ActionEvent evt) {
         owner.getDisplay().setLimits(-2.5,1.1,-1.35,1.35);
      }
   };
   
   
   private Action allDefaults = new AbstractAction(I18n.tr("command.restoreAllDefaults")) {
         // Restores default settings for limtis, palette type, palette lenght, and maxIterations.
      public void actionPerformed(ActionEvent evt) {
         owner.getDisplay().setLimits(-2.5,1.1,-1.35,1.35);
         paletteManager.setDefault();
         paletteLengthManager.setDefault();
         maxIterationsManager.setDefault();
      }
   };
   
   
   private Action undoChangeOfLimits = new AbstractAction(I18n.tr("command.undoChangeOfLimits")) {
          // Restores previous xy-limits on MandelbrotPanel.  The previous limits are
          // obtained from a property change event that is emitted by the display whenever
          // the limits change.  The listener stores the old limits in the previousLimits
          // instance variable.
      public void actionPerformed(ActionEvent evt) {
         if (previousLimits != null)
            owner.getDisplay().setLimits(previousLimits[0],previousLimits[1],
                                           previousLimits[2],previousLimits[3]);
      }
   };
   
   
   private Action showLimits = new AbstractAction(I18n.tr("command.showLimits")) {
          // Puts up a message dialog that contains the current range of xy-values
          // that is shown in the MandelbrotDisplay.
      public void actionPerformed(ActionEvent evt) {
         String[] limits = makeScaledLimitStrings();
         JOptionPane.showMessageDialog(owner, 
               I18n.tr("dialog.showLimits",limits[0],limits[1],limits[2],limits[3]));
      }
   };
   
   
   private Action setImageSize = new AbstractAction(I18n.tr("command.enterImageSize")) {
          // Puts up a dialog box of type SetImageSizeDialog (another class defined in
          // this package).  The dialog box lets the user enter new values for the
          // width and height of the image.  If the user does not cancel, then the
          // new width and height are applied to the image.  The frame changes size
          // to match the new size.  However, the size is not allowed to grow bigger
          // than will fit on the screen.
      public void actionPerformed(ActionEvent evt) {
         Dimension oldSize = owner.getDisplay().getSize();
         Dimension newSize = SetImageSizeDialog.showDialog(frame, oldSize);
         if (newSize == null)
            return;
         owner.getDisplay().setPreferredSize(newSize);  // Change the size that the display wants to be.
         frame.pack();  // Sizes the window to accomodate the preferred size.
         frame.adjustToScreenIfNecessary();  // Make sure frame fits on the screen.
      }
   };
   
    
   private Action setLimits= new AbstractAction(I18n.tr("command.enterLimits")) {
         // Puts up a dialog box of type SetLimitsDialog (another class defined in
         // this package.  The dialog box lets the user enter new values for xmin,
         // xmax, ymin, and ymax (the limits of the range of xy-values shown in the
         // MandelbrotDisplay).  If the user does not cancel, the new limits are
         // applied to the display.
      public void actionPerformed(ActionEvent evt) {
         String[] limits = makeScaledLimitStrings();
         double[] newLimits = SetLimitsDialog.showDialog(frame, limits);
         if (newLimits != null)
            owner.getDisplay().setLimits(newLimits[0],newLimits[1],newLimits[2],newLimits[3]);
      }
   };
    
   
   
   /**
    * Defines the object that manages the Palette menu.
    */
   private class PaletteManager implements ActionListener{
      
      JRadioButtonMenuItem[] items;  // Array ontains all the items that are in the Palette menu.
      int selectedItem = 0;  // Index in the items array of the item that is currently selected.
      private String[] valueStrings = {"Spectrum","PaleSpectrum","Grayscale","ReverseGrayscale",
                       "BlackToRed","RedToCyan","OrangeToBlue"};  // Names for commands in XML settings file.
      
      PaletteManager() {
            // Constructor creates the items and adds them to a ButtonGroup.  Also this
            // object adds itself as an ActionListener to each item so it can carry out
            // the command when the user selects one of the items.
         items = new JRadioButtonMenuItem[8];
         items[0] = new JRadioButtonMenuItem(I18n.tr("command.palette.spectrum"));
         items[1] = new JRadioButtonMenuItem(I18n.tr("command.palette.paleSpectrum"));
         items[2] = new JRadioButtonMenuItem(I18n.tr("command.palette.grayscale"));
         items[3] = new JRadioButtonMenuItem(I18n.tr("command.palette.reverseGrayscale"));
         items[4] = new JRadioButtonMenuItem(I18n.tr("command.palette.gradientBlackToRed"));
         items[5] = new JRadioButtonMenuItem(I18n.tr("command.palette.gradientRedToCyan"));
         items[6] = new JRadioButtonMenuItem(I18n.tr("command.palette.gradientOrangeToBlue"));