ColorCoder.java

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		if(args.length < 2) {
			System.out.println("Not enough arguments given!");
			System.out.println("\"command encode [PATH]\" - to encode text and save to given path");
			System.out.println("\"command decode [PATH]\" - to decode given file and print to console");
			System.exit(0);
		}
		try {
			String tempString = "";
			ArrayList<Integer> colors = new ArrayList<>();
			BufferedImage img;

			if(args[0].equals("encode")) {
				Scanner in = new Scanner(System.in);

				loop:
					for (;;) {
						System.out.println("Write something in ASCII:");
						String input = in.nextLine();

						for(char har : input.toCharArray()) {
							String numR = getNumber(har);
							if(numR==null) {
								System.out.println("Text must only contain ASCII characters!");
								continue loop;
							}
							tempString += numR;
						}

						int rgb=0, stg=0;
						while (tempString.length() > 0) {
							int num = Integer.valueOf(String.format("%1$-8s",tempString.substring(0,Math.min(8, tempString.length()))).replace(" ", "0"), 2);
							tempString = tempString.substring(Math.min(8, tempString.length()));

							if(stg==3) {
								colors.add(rgb | num<<24);
								rgb = 0; stg = -1;
							} else rgb |= num << (8*(2-stg));
							++stg;
						}

						if(stg != 0)
							colors.add(rgb);

						int size = (int)Math.sqrt(colors.size());
						int size2 = size + (Math.sqrt(colors.size())-size>0?1:0);

						img = new BufferedImage(size, size2, BufferedImage.TYPE_INT_ARGB);

						for(int y=0, i=0; y<size2; y++) {
							for(int x=0; x<size; x++) {
								img.setRGB(x, y, colors.get(i));
								if(++i>=colors.size()) break;
							}
						}

						ImageIO.write(img, "png", new File(args[1]));
						System.out.println("Image saved as: " + new File(args[1]).getName());
						in.close();
						break;
					}
			} else {
				try {
					img = ImageIO.read(new URL(args[1]));
				} catch (MalformedURLException r) {
					img = ImageIO.read(new File(args[1]));
				}

				for(int i=0; i < img.getHeight(); i++)
					for (int j = 0; j < img.getWidth(); j++)
						tempString += get8Number((img.getRGB(j, i) >> 16) & 0xFF) + get8Number((img.getRGB(j, i) >> 8) & 0xFF)
								+ get8Number(img.getRGB(j, i) & 0xFF) + get8Number((img.getRGB(j, i) >> 24) & 0xFF);

				while (tempString.length() > 0) {
					System.out.print((char)(int)Integer.valueOf(tempString.substring(0, Math.min(7, tempString.length())), 2));
					tempString = tempString.substring(Math.min(7, tempString.length()));
				}

			}

		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public static String getNumber(char chr) {
		return ((int)chr)>=0&&((int)chr)<=127?String.format("%7s", Integer.toBinaryString((int)chr)).replace(" ", "0"):null;
	}

	public static String get8Number(int num) {
		return String.format("%8s", Integer.toBinaryString(num)).replace(" ", "0");
	}

}