import java.applet.*;
import java.awt.*;
import java.net.*;
import java.util.*;
import java.io.*;

public class Imagemap extends Applet {
  protected Image image;       // image to display.
  protected Vector rects;      // list of rectangles in it.

  // init
  //
  public void init() {
    Graphics g = this.getGraphics();
    g.drawString("trying to get image",25,50);

    // load the image to be displayed.
    image = this.getImage(this.getDocumentBase(),this.getParameter("image"));
    
    // lookup a list of rectangular areas and URLs they map to.
    rects = new Vector();
    ImagemapRectangle r;
    int i = 0;
    while ( (r=getRectangleParameter("rect"+i)) != null) {
      rects.addElement(r);
      i++;
    }
  }

  // destroy
  //
  // Called when the applet is being unloaded from the system.
  // We use it here to "flush" the image. They may result in memory
  // and other resources being freed quicker than they otherwise would.
  public void destroy() {image.flush(); }

  // paint
  //
  // Display the image
  public void paint(Graphics g) { 
    g.drawImage(image,0,0,this);
  }

  // update
  //
  // We override this method so that it doesn't clear the background
  // before calling paint(). Makes for less flickering in some situations.
  public void update(Graphics g) { paint(g); }

  // findrect
  //
  // Find the rectangle we're inside
  private ImagemapRectangle findrect(int x, int y) {
    int i;
    ImagemapRectangle r = null;
    for (i=0; i<rects.size(); i++) {
      r = (ImagemapRectangle) rects.elementAt(i);
      if (r.inside(x,y)) break;
    }
    if (i<rects.size()) return r;
    else return null;
  }

  private ImagemapRectangle lastrect;

  // On button down, highlight the rectangle and display a message
  public boolean mouseDown(Event e, int x, int y) {
    ImagemapRectangle r = findrect(x,y);
    if (r==null) return false;
    Graphics g = this.getGraphics();
    g.setXORMode(Color.red);
    g.drawRect(r.x,r.y,r.width,r.height);
    lastrect = r;
    this.showStatus("To: "+r.url);
    return true;
  }

  // On button up, unhighlight the rectangle.
  // If still inside the rectangle, go to the URL
  public boolean mouseUp(Event e, int x, int y) {
    if (lastrect != null) {
      Graphics g = this.getGraphics();
      g.setXORMode(Color.red);
      g.drawRect(lastrect.x, lastrect.y, lastrect.width, lastrect.height);
      this.showStatus("");
      ImagemapRectangle r = findrect(x,y);
      if ((r!=null) && (r==lastrect))
	this.getAppletContext().showDocument(r.url);
      lastrect = null;
    }
    return true;
  }

  // Parse a comma-separated list of rectangel coordinates and a URL
  protected ImagemapRectangle getRectangleParameter(String name) {
    int x,y,w,h;
    URL url;
    String value = this.getParameter(name);
    if (value == null) return null;

    try {
      StringTokenizer st = new StringTokenizer(value, ",");
      x = Integer.parseInt(st.nextToken());
      y = Integer.parseInt(st.nextToken());
      w = Integer.parseInt(st.nextToken());
      h = Integer.parseInt(st.nextToken());
      url = new URL(this.getDocumentBase(), st.nextToken());
    }
    catch(NoSuchElementException e) return null;
    catch(NumberFormatException e) return null;
    catch(MalformedURLException e) return null;

    return new ImagemapRectangle(x,y,w,h,url);
  }
}

// A helper class. Just like java.awt.Rectangle, but with a new URL field.
// The constructor lets us create them from parameter specifications
class ImagemapRectangle extends Rectangle {
  URL url;
  public ImagemapRectangle(int x, int y, int w, int h, URL url) {
    super(x,y,w,h);
    this.url = url;
  }
}