RGBAPacked.java

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

public class Main {

	public static void main(String[] args) {
		if(args.length == 0) {
			System.out.println("No arguments given!");
			System.out.println("\"command encode\" - to encode text and save as out.png");
			System.out.println("\"command [PATH]\" - to decode given file and print to console");
			System.exit(0);
		}
		try {
			String tempString = "";
			ArrayList<Color> colors = new ArrayList<>();
			BufferedImage img;
			if(args[0].equals("encode")) {

				System.out.println("Write something in ASCII:");
				Scanner in = new Scanner(System.in);
				String input = in.nextLine();
				in.close();

				for(char har : input.toCharArray())
					tempString += getNumber(har);

				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(new Color(rgb | num<<24, true));
						rgb = 0; stg = -1;
					} else rgb |= num << (8*(2-stg));
					++stg;
				}

				if(stg != 0)
					colors.add(new Color(rgb, true));

				img = new BufferedImage(colors.size(), 1, BufferedImage.TYPE_INT_ARGB);

				for(int i=0; i<colors.size(); i++)
					img.setRGB(i, 0, colors.get(i).getRGB());

				ImageIO.write(img, "png", new File("out.png"));

			} else {
				img = ImageIO.read(new File(args[0]));

				for(int i=0; i < img.getWidth(); i++) {
					Color color = new Color(img.getRGB(i, 0), true);
					tempString += get8Number(color.getRed()) + get8Number(color.getGreen()) + get8Number(color.getBlue()) + get8Number(color.getAlpha());
				}

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

			}

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

	public static String getNumber(char chr) {
		return String.format("%7s", Integer.toBinaryString((int)chr)).replace(" ", "0");
	}

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

}