ASCIIArt.java

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.file.NoSuchFileException;
import java.util.Scanner;

import static java.lang.System.out;

/**
 * Created by User on 7/25/2016.
 */


public class ASCIIArt {

    static BufferedImage imgRead = null;
    static BufferedWriter writer = null;

    public static void main(String[] args) {
        Scanner inp = new Scanner(System.in);
        int tempInp = 0;
        int artWidth = 0;
        int artHeight = 0;

        try {
            writer = new BufferedWriter(new FileWriter("output.txt"));
        } catch (Exception e) {
            out.println("Unable to create text file for output.");
            System.exit(0);
        }

        //get a valid BufferedImage
        try {
            imgRead = ImageIO.read(new File("ASCII.jpg"));
        } catch (NoSuchFileException e) {
            out.println("Please put a .jpg image into the folder.");
            System.exit(0);
        } catch (Exception e) {
            out.println("Only .jpg format supported at this time.");
            System.exit(0);
        }

        //get the desired width (in characters), making sure it is less than the image width and not 0 or less.
        boolean invalidInp = false;
        out.println("How many pixels width-wise do you want to be represented per ASCII character?" +
                "\nExample: If the input is 10, then a 400x200 image would be represented by a text file of 40x10.");
        do {
            try {
                tempInp = Integer.parseInt(inp.nextLine());
                invalidInp = false;
            } catch (Exception e) {
                out.println("Please input a number.");
                invalidInp = true;
            }
            if (tempInp > imgRead.getWidth() && !invalidInp) {
                out.println("Please input a number that is less than or equal to the original dimensions of the picture.");
                invalidInp = true;
            } else if (tempInp < 1 && !invalidInp) {
                out.println("Please input a positive number.");
                invalidInp = true;
            }
        } while (invalidInp);
        artWidth = tempInp;
        //Text is twice as tall as it is wide, so we have to half the number of characters per pixel height-wise
        artHeight = artWidth * 2;

        //shaves off pixels that make the image dimensions indivisible with the desired width
        int nHeight = imgRead.getHeight();
        int nWidth = imgRead.getWidth();
        if (imgRead.getHeight() % artHeight != 0) {
            nHeight = nHeight - (imgRead.getHeight() % artHeight);
        }
        if (imgRead.getWidth() % artWidth != 0) {
            nWidth = nWidth - (imgRead.getWidth() % artWidth);
        }

        int count = 0;
        for (int r = 0; r < nHeight; r += artHeight) {
            for (int c = 0; c < nWidth; c += artWidth) {
                int totalR = 0;
                int totalG = 0;
                int totalB = 0;
                Double avgBright = 0.0;
                for (int x = c; x < c + artWidth; x++) {
                    for (int y = r; y < r + artHeight; y++) {
                        Color getColor = new Color(imgRead.getRGB(x, y));
                        totalR += getColor.getRed();
                        totalG += getColor.getGreen();
                        totalB += getColor.getBlue();
                        count++;
                    }
                }
                avgBright = (Math.sqrt(0.299 * totalR * totalR + 0.587 * totalG * totalG + 0.114 * totalB * totalB) / (artWidth * artHeight));
                //out.println(count + " " + avgBright);
                try {
                    printChar(avgBright);
                } catch (IOException e) {
                    e.printStackTrace();
                    System.exit(1);
                }
            }
            try {
                writer.newLine();
            } catch (Exception e) {
                e.printStackTrace();
                System.exit(1);
            }
        }
        try {
            writer.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
        out.close();

    }

    private static void printChar(Double avgBright) throws IOException {

        //this organization is fucking AIDS but it makes a mostly decipherable picture
        if (avgBright < 15) {
            writer.write('█');
            return;
        }
        if (avgBright < 30) {
            writer.write('▓');
            return;
        }
        if (avgBright < 50) {
            writer.write('▒');
            return;
        }
        if (avgBright < 65) {
            writer.write('░');
            return;
        }
        if (avgBright < 80) {
            writer.write('X');
            return;
        }
        if (avgBright < 100) {
            writer.write('E');
            return;
        }
        if (avgBright < 115) {
            writer.write('S');
            return;
        }
        if (avgBright < 130) {
            writer.write('7');
            return;
        }
        if (avgBright < 145) {
            writer.write('1');
            return;
        }
        if (avgBright < 150) {
            writer.write(':');
            return;
        }
        if (avgBright < 170) {
            writer.write('<');
            return;
        }
        if (avgBright < 190) {
            writer.write('-');
            return;
        }
        if (avgBright < 210) {
            writer.write('`');
            return;
        }
        if (avgBright < 230) {
            writer.write('.');
        } else {
            writer.write(' ');
        }
    }
}