Main.java

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;


import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Scanner;

import javax.imageio.ImageIO;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner scanner = new Scanner(System.in);
        System.out.println("\nPlease enter the text:\n");
        String data = scanner.nextLine();
        System.out.println("\nPlease enter a name for the QR:\n");
        String qrName = scanner.next();
        System.out.println("\nPlease enter the error correction level (1 - 4):");
        int errorCorrectionLevel = scanner.nextInt();
        scanner.close();
        if(errorCorrectionLevel < 1 || errorCorrectionLevel > 4) throw new Exception("Please eneter a valid error correction level number (1 - 4)! Try again.");
        QR qr = new QR(data, errorCorrectionLevel);
        Packed resultQRPacked = qr.generateQR();

        int width = resultQRPacked.size + 10;
        int height = resultQRPacked.size + 10;

        int sizeMultiplayer;

        if (resultQRPacked.size < 15) {
            sizeMultiplayer = 10;
        } else {
            sizeMultiplayer = 5;
        }


        BufferedImage bufferedImage = new BufferedImage(width * sizeMultiplayer, height * sizeMultiplayer, BufferedImage.TYPE_INT_RGB);

        Graphics2D g2d = bufferedImage.createGraphics();

        g2d.setColor(Color.white);
        g2d.fillRect(0, 0, width * sizeMultiplayer, height * sizeMultiplayer);

        if (resultQRPacked.state >= 0) {
            for (int x = 0; x < resultQRPacked.size; x++) {
                for (int y = 0; y < resultQRPacked.size; y++) {
                    if (resultQRPacked.matrix[x][y]) {
                        g2d.setColor(Color.black);
                    } else {
                        g2d.setColor(Color.white);
                    }
                    g2d.fillRect((x + 5) * sizeMultiplayer, (y + 5) * sizeMultiplayer, sizeMultiplayer, sizeMultiplayer);
                }
            } 
        } else {
            System.out.println("build faild with output: " + Integer.toString(resultQRPacked.state));
            Exception e = new Exception("An exception occurred!");
            throw e;
        }

        g2d.dispose();

        File dir = new File(System.getProperty("user.dir") + "\\generated images");
        File file = new File(dir.getAbsolutePath() + "\\" + qrName + ".png");

        try {
            dir.mkdir();
            file.createNewFile();
            ImageIO.write(bufferedImage, "png", file);
        } catch (IOException e) {
            throw new IOException("An error occurred while trying to create the image png file!");
        }


        JFrame f = new JFrame(qrName);
        JLabel label = new JLabel(new ImageIcon(file.getAbsolutePath()));
        label.setBounds(-4, -4, width * sizeMultiplayer + 10, height * sizeMultiplayer + 10);
        f.add(label);
        f.setSize(width * sizeMultiplayer + 14 , height * sizeMultiplayer + 40);  
        f.setLayout(null);  
        f.setVisible(true);
    }
}