third_party_qrcodegen/java/QrCodeGeneratorDemo.java

/* 
 * QR Code generator demo (Java)
 * 
 * Run this command-line program with no arguments. The program creates/overwrites a bunch of
 * PNG and SVG files in the current working directory to demonstrate the creation of QR Codes.
 * 
 * Copyright (c) 2016 Project Nayuki
 * https://www.nayuki.io/page/qr-code-generator-library
 * 
 * (MIT License)
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 * - The above copyright notice and this permission notice shall be included in
 *   all copies or substantial portions of the Software.
 * - The Software is provided "as is", without warranty of any kind, express or
 *   implied, including but not limited to the warranties of merchantability,
 *   fitness for a particular purpose and noninfringement. In no event shall the
 *   authors or copyright holders be liable for any claim, damages or other
 *   liability, whether in an action of contract, tort or otherwise, arising from,
 *   out of or in connection with the Software or the use or other dealings in the
 *   Software.
 */

package io.nayuki.qrcodegen;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.List;
import javax.imageio.ImageIO;


public final class QrCodeGeneratorDemo {
	
	// The main application program.
	public static void main(String[] args) throws IOException {
		doBasicDemo();
		doVarietyDemo();
		doSegmentDemo();
	}
	
	
	// Creates a single QR Code, then writes it to a PNG file and an SVG file.
	private static void doBasicDemo() throws IOException {
		String text = "Hello, world!";          // User-supplied Unicode text
		QrCode.Ecc errCorLvl = QrCode.Ecc.LOW;  // Error correction level
		
		QrCode qr = QrCode.encodeText(text, errCorLvl);  // Make the QR Code symbol
		
		BufferedImage img = qr.toImage(10, 4);          // Convert to bitmap image
		File imgFile = new File("hello-world-QR.png");  // File path for output
		ImageIO.write(img, "png", imgFile);             // Write image to file
		
		String svg = qr.toSvgString(4);  // Convert to SVG XML code
		try (Writer out = new OutputStreamWriter(
				new FileOutputStream("hello-world-QR.svg"),
				StandardCharsets.UTF_8)) {
			out.write(svg);  // Create/overwrite file and write SVG data
		}
	}
	
	
	// Creates a variety of QR Codes that exercise different features of the library, and writes each one to file.
	private static void doVarietyDemo() throws IOException {
		QrCode qr;
		
		// Project Nayuki URL
		qr = QrCode.encodeText("https://www.nayuki.io/", QrCode.Ecc.HIGH);
		qr = new QrCode(qr, 3);  // Change mask, forcing to mask #3
		writePng(qr.toImage(8, 6), "project-nayuki-QR.png");
		
		// Numeric mode encoding (3.33 bits per digit)
		qr = QrCode.encodeText("314159265358979323846264338327950288419716939937510", QrCode.Ecc.MEDIUM);
		writePng(qr.toImage(13, 1), "pi-digits-QR.png");
		
		// Alphanumeric mode encoding (5.5 bits per character)
		qr = QrCode.encodeText("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", QrCode.Ecc.HIGH);
		writePng(qr.toImage(10, 2), "alphanumeric-QR.png");
		
		// Unicode text as UTF-8, and different masks
		qr = QrCode.encodeText("こんにちwa、世界！ αβγδ", QrCode.Ecc.QUARTILE);
		writePng(new QrCode(qr, 0).toImage(10, 3), "unicode-mask0-QR.png");
		writePng(new QrCode(qr, 1).toImage(10, 3), "unicode-mask1-QR.png");
		writePng(new QrCode(qr, 5).toImage(10, 3), "unicode-mask5-QR.png");
		writePng(new QrCode(qr, 7).toImage(10, 3), "unicode-mask7-QR.png");
		
		// Moderately large QR Code using longer text (from Lewis Carroll's Alice in Wonderland)
		qr = QrCode.encodeText("Alice was beginning to get very tired of sitting by her sister on the bank, "
			+ "and of having nothing to do: once or twice she had peeped into the book her sister was reading, "
			+ "but it had no pictures or conversations in it, 'and what is the use of a book,' thought Alice "
			+ "'without pictures or conversations?' So she was considering in her own mind (as well as she could, "
			+ "for the hot day made her feel very sleepy and stupid), whether the pleasure of making a "
			+ "daisy-chain would be worth the trouble of getting up and picking the daisies, when suddenly "
			+ "a White Rabbit with pink eyes ran close by her.",
			QrCode.Ecc.HIGH);
		writePng(qr.toImage(6, 10), "alice-wonderland-QR.png");
	}
	
	
	// Creates QR Codes with manually specified segments for better compactness.
	private static void doSegmentDemo() throws IOException {
		QrCode qr;
		List<QrSegment> segs;
		
		// Illustration "silver"
		String silver0 = "THE SQUARE ROOT OF 2 IS 1.";
		String silver1 = "41421356237309504880168872420969807856967187537694807317667973799";
		qr = QrCode.encodeText(silver0 + silver1, QrCode.Ecc.LOW);
		writePng(qr.toImage(10, 3), "sqrt2-monolithic-QR.png");
		
		segs = Arrays.asList(
			QrSegment.makeAlphanumeric(silver0),
			QrSegment.makeNumeric(silver1));
		qr = QrCode.encodeSegments(segs, QrCode.Ecc.LOW);
		writePng(qr.toImage(10, 3), "sqrt2-segmented-QR.png");
		
		// Illustration "golden"
		String golden0 = "Golden ratio φ = 1.";
		String golden1 = "6180339887498948482045868343656381177203091798057628621354486227052604628189024497072072041893911374";
		String golden2 = "......";
		qr = QrCode.encodeText(golden0 + golden1 + golden2, QrCode.Ecc.LOW);
		writePng(qr.toImage(8, 5), "phi-monolithic-QR.png");
		
		segs = Arrays.asList(
			QrSegment.makeBytes(golden0.getBytes(StandardCharsets.UTF_8)),
			QrSegment.makeNumeric(golden1),
			QrSegment.makeAlphanumeric(golden2));
		qr = QrCode.encodeSegments(segs, QrCode.Ecc.LOW);
		writePng(qr.toImage(8, 5), "phi-segmented-QR.png");
	}
	
	
	// Helper function to reduce code duplication.
	private static void writePng(BufferedImage img, String filepath) throws IOException {
		ImageIO.write(img, "png", new File(filepath));
	}
	
}