import java.awt.*;
import java.awt.image.*;
import java.applet.*;
import java.net.*;
import java.io.*;
import java.lang.Math;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JApplet;
import javax.imageio.*;
import javax.swing.event.*;



public class sobelDemo extends JApplet {
	
	Image edgeImage, accImage, outputImage;
	MediaTracker tracker = null;
	PixelGrabber grabber = null;
	int width = 0, height = 0;
	String fileNames[] = {"lena.png", "microphone.png", "screw.png", "drawing.png", "film.png"};

	javax.swing.Timer timer;
	//slider constraints
	static final int TH_MIN = 0;
	static final int TH_MAX = 255;
	static final int TH_INIT = 60;
	int threshold=TH_INIT;
	boolean thresholdActive=false;

	int imageNumber=0;
	static int progress=0;
	public int orig[] = null;
	
	Image image[] = new Image[fileNames.length];
	
	JProgressBar progressBar;
	JPanel controlPanel, imagePanel, progressPanel;
	JLabel origLabel, outputLabel,comboLabel,sigmaLabel,thresholdLabel,processing;
	JSlider thresholdSlider;
	JButton thresholding;
	JComboBox imSel;
	static sobel edgedetector;
	 
	 
	   	// Applet init function	
	public void init() {
		
		tracker = new MediaTracker(this);
		for(int i = 0; i < fileNames.length; i++) {
			image[i] = getImage(this.getCodeBase(),fileNames[i]);
			image[i] = image[i].getScaledInstance(256, 256, Image.SCALE_SMOOTH);
			tracker.addImage(image[i], i);
		}
		try {
			tracker.waitForAll();
		}
		catch(InterruptedException e) {
			System.out.println("error: " + e);
		}
		
		Container cont = getContentPane();
		cont.removeAll();
		cont.setBackground(Color.black);
		cont.setLayout(new BorderLayout());
		
		controlPanel = new JPanel();
		controlPanel.setLayout(new GridLayout(2,3,15,0));
		controlPanel.setBackground(new Color(192,204,226));
		imagePanel = new JPanel();
		imagePanel.setBackground(new Color(192,204,226));
		progressPanel = new JPanel();
		progressPanel.setBackground(new Color(192,204,226));
		progressPanel.setLayout(new GridLayout(2,1));

		comboLabel = new JLabel("IMAGE");
		comboLabel.setHorizontalAlignment(JLabel.CENTER);
		controlPanel.add(comboLabel);
		sigmaLabel = new JLabel("");
		sigmaLabel.setHorizontalAlignment(JLabel.CENTER);
		controlPanel.add(sigmaLabel);
		thresholdLabel = new JLabel("Threshold Value = "+TH_INIT);
		thresholdLabel.setHorizontalAlignment(JLabel.CENTER);
		controlPanel.add(thresholdLabel);


		processing = new JLabel("Processing...");
		processing.setHorizontalAlignment(JLabel.LEFT);
		progressBar = new JProgressBar(0,100);
        progressBar.setValue(0);
        progressBar.setStringPainted(true); //get space for the string
        progressBar.setString("");          //but don't paint it
		progressPanel.add(processing);
		progressPanel.add(progressBar);
		
		width = image[imageNumber].getWidth(null);
		height = image[imageNumber].getHeight(null);

		imSel = new JComboBox(fileNames);
		imageNumber = imSel.getSelectedIndex();
		imSel.addActionListener( 
			new ActionListener() {  
				public void actionPerformed(ActionEvent e) {
					imageNumber = imSel.getSelectedIndex();
					origLabel.setIcon(new ImageIcon(image[imageNumber]));	
					processImage();
				}
			}
		);
		controlPanel.add(imSel, BorderLayout.PAGE_START);

        timer = new javax.swing.Timer(100, new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                progressBar.setValue(edgedetector.getProgress());
            }
        });

		origLabel = new JLabel("Original Image", new ImageIcon(image[imageNumber]), JLabel.CENTER);
		origLabel.setVerticalTextPosition(JLabel.BOTTOM);
		origLabel.setHorizontalTextPosition(JLabel.CENTER);
		origLabel.setForeground(Color.blue);
		imagePanel.add(origLabel);
		
		outputLabel = new JLabel("Edge Detected", new ImageIcon(image[imageNumber]), JLabel.CENTER);
		outputLabel.setVerticalTextPosition(JLabel.BOTTOM);
		outputLabel.setHorizontalTextPosition(JLabel.CENTER);
		outputLabel.setForeground(Color.blue);
		imagePanel.add(outputLabel);
	

		thresholding = new JButton("Thresholding Off");
		//thresholding.setVerticalTextPosition(AbstractButton.BOTTOM);
    	//thresholding.setHorizontalTextPosition(AbstractButton.CENTER);
		thresholding.setBackground(Color.RED);
		thresholding.addActionListener( 
			new ActionListener() {  
				public void actionPerformed(ActionEvent e) {
					if(thresholdActive==true){
						thresholdActive=false;
						thresholding.setBackground(Color.RED);
						thresholding.setText("Thresholding Off");
						thresholdSlider.setEnabled(false);
					}
					else{
						thresholdActive=true;
						thresholding.setBackground(Color.GREEN);
						thresholding.setText("Thresholding ON");
						thresholdSlider.setEnabled(true);
					}
					processImage();
				}
			}
		);
		controlPanel.add(thresholding);

		thresholdSlider = new JSlider(JSlider.HORIZONTAL, TH_MIN, TH_MAX, TH_INIT);
		thresholdSlider.addChangeListener(new thresholdListener());
		thresholdSlider.setMajorTickSpacing(40);
		thresholdSlider.setMinorTickSpacing(10);
		thresholdSlider.setPaintTicks(true);
		thresholdSlider.setPaintLabels(true);
		thresholdSlider.setBackground(new Color(192,204,226));
		controlPanel.add(thresholdSlider);



		cont.add(controlPanel, BorderLayout.NORTH);
		cont.add(imagePanel, BorderLayout.CENTER);
		cont.add(progressPanel, BorderLayout.SOUTH);

		processImage();

	}
  	class thresholdListener implements ChangeListener {
	    public void stateChanged(ChangeEvent e) {
	        JSlider source = (JSlider)e.getSource();
	        if (!source.getValueIsAdjusting()) {
				System.out.println("threshold="+source.getValue());
				threshold=source.getValue();
				thresholdLabel.setText("Threshold Value = "+source.getValue());
				processImage();
	        }    
	    }
	}
	public int[] threshold(int[] original, int value) {
		for(int x=0; x<original.length; x++) {
			if((original[x] & 0xff)>=value)
				original[x]=0xffffffff;
			else
				original[x]=0xff000000;
		}
		return original;
	}
	private void processImage(){
		orig=new int[width*height];
		PixelGrabber grabber = new PixelGrabber(image[imageNumber], 0, 0, width, height, orig, 0, width);
		try {
			grabber.grabPixels();
		}
		catch(InterruptedException e2) {
			System.out.println("error: " + e2);
		}
		progressBar.setMaximum(width-4);

		processing.setText("Processing...");
		thresholdSlider.setEnabled(false);
		thresholding.setEnabled(false);
		imSel.setEnabled(false);
		edgedetector = new sobel();
		timer.start();

		new Thread(){
			public void run(){
				edgedetector.init(orig,width,height);
				int[] res = edgedetector.process();
				if(thresholdActive==true)
					res=threshold(res, threshold);
				final Image output = createImage(new MemoryImageSource(width, height, res, 0, width));
				SwingUtilities.invokeLater(new Runnable() {
					public void run() {
						outputLabel.setIcon(new ImageIcon(output));	
						processing.setText("Done");
						if(thresholdActive==true){
							thresholdSlider.setEnabled(true);
							}
						thresholding.setEnabled(true);
						imSel.setEnabled(true);
					}
				});
			}
		}.start();
	}

}