Syfran.com

Not sure what motivated me here but I took a little time and came up with this. It takes the original image file ( can be a multitude of formats, has worked with both jpg and png so far) and outputs a grayscale image (jpeg or png).

Tux the penguin in full color.

The Aftermath

Here is the code… (hint

import javax.imageio.*;
import javax.imageio.*;
import java.io.*;
import java.awt.image.*;

public class GreyScale {
        public static void main(String [] pie) {

                // Argument Checks
                if(!((pie.length == 3) && (new File(pie[0]).exists()) && (pie[2].equals("jpeg") || pie[2].equals("png"
                        System.out.println("Usage: java GreyScale {original image} {modified image} {Output Format}\nO
                        System.exit(0);
                }

                BufferedImage image = null;
                try {
                image = ImageIO.read(new File(pie[0])); // Read in the original file
                } catch(IOException e) {
                        System.err.println("Error reading in file, check file name and format");
                        System.exit(0);
                }

                // loop through every pixel in the image
                for(int x = 0; x <image.getWidth(); x ++) {
                        for(int y = 0; y < image.getHeight(); y++) {
                                int RGB = image.getRGB(x,y);            // Get the rgb of the pixel
                                int blue = (RGB & 0x000000FF);
                                int green = (RGB & 0x0000FF00) >> 8;
                                int red = (RGB & 0x00FF0000) >> 16;
                                int average = (int) ((.11 * blue) + (.59 * green) + (.3 * red));
                                int newRGB = 0xFF000000 + (average << 16) + (average << 8) + average; // and reassign
                                image.setRGB(x,y,newRGB);
                        }
                }
                try {
                        ImageIO.write(image, pie[2], new File(pie[1])); // Writes the new greyscale file.
                } catch(IOException e) {
                        System.err.println("Unable to output results");
                }

        }
}

UPDATE: Edited thanks to the comment from Gasper. Swapped out the Color class for bitwise operations and it seems to be working well. Also figured out how to format the code in a way that looks better.

UPDATE: Updated to use a different algorithm for finding the grey intensity. Instead of averaging used values based on human vision. (30% red, 59% Green, 11% Red) Taken from Wikipedia.

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