import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.util.*;
import java.lang.*;

// use the old event model to be compatible with Java 1.1.5

public class PixelView extends Applet implements AdjustmentListener {

  Label label;
  Scrollbar scrollbar;
  Image image;
  String param;
  int imageHeight, imageWidth;
  int appletHeight, appletWidth;
  int imageLoadLine;

  public void init() {

    appletHeight = getHeight();
    appletWidth = getWidth();

    String imageFilename = getParameter("filename");
    if (imageFilename == null) imageFilename = getParameter("image");

    image = loadImage(imageFilename);
    imageHeight = image.getHeight(this);
    imageWidth = image.getWidth(this);
    System.out.println("####  For image "+imageFilename+"  width="+
            imageWidth+"  height="+imageHeight);

    String res = getParameter("starting_pixels");
    int npix = 50;
    if (res != null) {
      npix = Integer.parseInt(res);
    }
    // orientation, initial value, size of bubble, minimum, maximum
    scrollbar = new Scrollbar(Scrollbar.HORIZONTAL, npix, 10, 2, imageWidth+10);
    scrollbar.addAdjustmentListener(this);

    label = new Label("Number of pixels in image = "+imageWidth+" x "+imageHeight+" = "+(imageWidth * imageHeight));

    setLayout(null);
    add(scrollbar);
    add(label);

    validate();

    Dimension dim = scrollbar.getPreferredSize();
    Dimension dimlab = label.getPreferredSize();
    int swid = 200;
    int wid = swid + dimlab.width+20;
    if (wid > appletWidth) {
      swid = appletWidth - dimlab.width - 25;
      wid = swid + dimlab.width + 20;
    }

    int widloc = appletWidth/2 - wid/2;
    if (widloc < 0) widloc = 0;

    scrollbar.setBounds(widloc,5,200,dim.height);
    label.setBounds(widloc+220,5,dimlab.width,dimlab.height);

    imageLoadLine = 10+(dim.height > dimlab.height ? dim.height : dimlab.height);   
    repaint();

  }

  public void update(Graphics g) { paint(g); }

  public void paint(Graphics g) {
    Image buffer = createImage(appletWidth, appletHeight);
    Graphics gb = buffer.getGraphics();
    int n = scrollbar.getValue();
    label.setText("Number of pixels in image = "+n+" x "+n+" = "+(n*n));
    Image subimage = createImage(n,n);
    Graphics gs = subimage.getGraphics();
    gs.drawImage(image,0,0,n,n,0,0,imageWidth,imageHeight,this);
    gb.drawImage(subimage,0,0,imageWidth,imageHeight,0,0,n,n,this);

    g.drawImage(buffer,0,imageLoadLine,this);
    buffer.flush();
    gb.dispose();
    subimage.flush();
    gs.dispose();
  }

  // Listeners

  public void adjustmentValueChanged(AdjustmentEvent e) {
    if (e.getSource() == scrollbar) {
      repaint();
    }
  }


  // Utilities for getting images and audio clips from JAR or URL
  public Image loadImage(String name) {
    // first try the URL

    Image img = null;
    URL u = getClass().getResource( (String) name);
    if (u == null) {
      u = getDocumentBase();
      img = getImage(u,name);
    } else {
      img = getImage(u);
    }

		MediaTracker mt = new MediaTracker(this);
		mt.addImage(img, 0);
		try   { mt.waitForAll(); }
		catch ( Exception ex ) {img = null; }
    return img;

  }

}