// This example is from _Java Examples in a Nutshell_. (http://www.oreilly.com)
// Copyright (c) 1997 by David Flanagan
// This example is provided WITHOUT ANY WARRANTY either expressed or implied.
// You may study, use, modify, and distribute it for non-commercial purposes.
// For any commercial use, see http://www.davidflanagan.com/javaexamples

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

/**
 * This program displays Unicode glyphs using user-specified fonts
 * and font styles.
 **/
public class UnicodeDisplay extends Frame implements ActionListener
{
  int page = 0; 
  UnicodePanel p;
  Scrollbar b;
  String fontfamily = "Serif";
  int fontstyle = Font.PLAIN;

  /** 
   * This constructor creates the frame, menubar, and scrollbar
   * that work along with the UnicodePanel class, defined below
   **/
  public UnicodeDisplay(String name) {
    super(name);
    this.setLayout(new BorderLayout());
    p = new UnicodePanel();                // Create the panel
    p.setBase((char)(page * 0x100));       // Initialize it
    this.add(p, "Center");                 // Center it

    // Create and set up a scrollbar, and put it on the right
    b = new Scrollbar(Scrollbar.VERTICAL, 0, 1, 0, 0xFF);
    b.setUnitIncrement(1);
    b.setBlockIncrement(0x10);
    b.addAdjustmentListener(new AdjustmentListener() {
      public void adjustmentValueChanged(AdjustmentEvent e) {
        page = e.getValue();
        p.setBase((char)(page * 0x100));
      }
    });
    this.add(b, "East");

    // Set things up so we respond to window close requests
    this.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        UnicodeDisplay.this.dispose();
        System.exit(0);
      }
    });

    // Handle Page Up and Page Down and the up and down arrow keys
    this.addKeyListener(new KeyAdapter() {
      public void keyPressed(KeyEvent e) {
        int code = e.getKeyCode();
        int oldpage = page;
        if ((code == KeyEvent.VK_PAGE_UP) || (code == KeyEvent.VK_UP)) {
          if (e.isShiftDown()) page -= 0x10;
          else page -= 1;
          if (page < 0) page = 0;
        }
        else if ((code == KeyEvent.VK_PAGE_DOWN) || (code==KeyEvent.VK_DOWN)) {
          if (e.isShiftDown()) page += 0x10;
          else page += 1;
          if (page > 0xff) page = 0xff;
        }
        if (page != oldpage) {              // if anything has changed...
          p.setBase((char) (page * 0x100)); // update the display
          b.setValue(page);                 // and update scrollbar to match
        }
      }
    });

    // Set up a menu system to change fonts.  Use a convenience method.
    MenuBar menubar = new MenuBar();
    this.setMenuBar(menubar);
    menubar.add(makemenu("Font Family", 
                         new String[] {"Serif", "SansSerif", "Monospaced"},
                         this));
    menubar.add(makemenu("Font Style", 
                         new String[]{"Plain", "Italic", "Bold", "BoldItalic"},
                         this));
  }

  /** This method handles the items in the menubars */
  public void actionPerformed(ActionEvent e) {
    String cmd = e.getActionCommand();
    if (cmd.equals("Serif")) fontfamily = "Serif";
    else if (cmd.equals("SansSerif")) fontfamily = "SansSerif";
    else if (cmd.equals("Monospaced")) fontfamily = "Monospaced";
    else if (cmd.equals("Plain")) fontstyle = Font.PLAIN;
    else if (cmd.equals("Italic")) fontstyle = Font.ITALIC;
    else if (cmd.equals("Bold")) fontstyle = Font.BOLD;
    else if (cmd.equals("BoldItalic")) fontstyle = Font.BOLD + Font.ITALIC;
    p.setFont(fontfamily, fontstyle);
  }

  /** A convenience method to create a Menu from an array of items */
  private Menu makemenu(String name, String[] itemnames, 
                        ActionListener listener) {
    Menu m = new Menu(name);
    for(int i = 0; i