import java.awt.*;
import java.awt.image.*;
import javax.swing.*;

/**
 * OFImage is a class that defines an image in OF (Objects First) format.
 * 
 * @author Michael Kölling and David J. Barnes.
 * @version 1.1
 */
public class OFImage extends BufferedImage
{
    /**
     * Create an OFImage copied from a BufferedImage.
     * @param image The image to copy.
     */
    public OFImage(BufferedImage image)
    {
         super(image.getColorModel(), image.copyData(null), 
               image.isAlphaPremultiplied(), null);
    }

    /**
     * Create an OFImage with specified size and unspecified content.
     * @param width The width of the image.
     * @param height The height of the image.
     */
    public OFImage(int width, int height)
    {
        super(width, height, TYPE_INT_RGB);
    }

    /**
     * Set a given pixel of this image to a specified color. The
     * color is represented as an (r,g,b) value.
     * @param x The x position of the pixel.
     * @param y The y position of the pixel.
     * @param col The color of the pixel.
     */
    public void setPixel(int x, int y, Color col)
    {
        int pixel = col.getRGB();
        setRGB(x, y, pixel);
    }
    
    /**
     * Get the color value at a specified pixel position.
     * @param x The x position of the pixel.
     * @param y The y position of the pixel.
     * @return The color of the pixel at the given position.
     */
    public Color getPixel(int x, int y)
    {
        int pixel = getRGB(x, y);
        return new Color(pixel);
    }

    /**
     * Make this image a bit darker.
     */
    public void darker()
    {
        int height = getHeight();
        int width = getWidth();
        for(int y = 0; y < height; y++) {
            for(int x = 0; x < width; x++) {
                setPixel(x, y, getPixel(x, y).darker());
            }
        }
    }

    /**
     * Make this image a bit lighter.
     */
    public void lighter()
    {
        int height = getHeight();
        int width = getWidth();
        for(int y = 0; y < height; y++) {
            for(int x = 0; x < width; x++) {
                setPixel(x, y, getPixel(x, y).brighter());
            }
        }
    }

    /**
     * Perform a three level threshold operation.
     * That is: repaint the image with only three color values:
     *          white, gray, and black.
     */
    public void threshold()
    {
        int height = getHeight();
        int width = getWidth();
        for(int y = 0; y < height; y++) {
            for(int x = 0; x < width; x++) {
                Color pixel = getPixel(x, y);
                int brightness = (pixel.getRed() + pixel.getBlue() + pixel.getGreen()) / 3;
                if(brightness <= 85) {
                    setPixel(x, y, Color.BLACK);
                }
                else if(brightness <= 170) {
                    setPixel(x, y, Color.GRAY);
                }
                else {
                    setPixel(x, y, Color.WHITE);
                }
            }
        }
    }
}