import java.applet.*;
import java.awt.*;
import java.awt.image.*;

public class SimpleDithering extends Applet
{

	Image backImage;
	Button button;
	TextField textField;
	Label labelField;

	final int WIDTH = 256;
	final int HEIGHT = 256;

	public void init()
	{
		this.draw (0, 255, 0);
		button = new Button("Red");
		add(button);
		button = new Button("Green");
		add(button);
		button = new Button("Blue");
		add(button);
		labelField = new Label("Intensity");
		add(labelField);
		textField = new TextField(3);
		add(textField);
		textField.setText("255");
		repaint();
	}

	public boolean action(Event event, Object arg)
	{
		try
		{
			String str = textField.getText();
			int intensity = Integer.parseInt(str);
			if (intensity < 0) { intensity = 0; textField.setText("0"); }
			if (intensity > 255) { intensity = 255; textField.setText("255"); }
			repaint();

			if (arg == "Red") this.draw (intensity, 0, 0);
			else if (arg == "Green") this.draw (0, intensity, 0);
			else if (arg == "Blue") this.draw (0, 0, intensity);
		}
		catch (Exception e)
		{
		}

		repaint();
		return true;
	}

	public void draw(int r, int g, int b)
	{

		int imageBits[] = new int[WIDTH * HEIGHT];

		for (int row = 0; row < HEIGHT; ++row)
		{
			int red = (row * r) / (HEIGHT - 1);
			int green = (row * g) / (HEIGHT - 1);
			int blue = (row * b) / (HEIGHT - 1);
			int alpha = 255;

			for (int col = 0; col < WIDTH; ++col)
			{
				int index = row * WIDTH + col;
				imageBits[index++] = (alpha << 24) | (red << 16) | (green << 8) | blue;
			}
		}

		MemoryImageSource producer = new MemoryImageSource (WIDTH, HEIGHT, imageBits, 0, WIDTH);
		backImage = createImage(producer);
	}

	public void paint(Graphics g)
	{
		g.drawImage(backImage, 0, 0, this);
	}
}