itextpdf.jar is a component in iText 5 Java library to provide core functionalities. iText Java library allows you to generate and manage PDF documents.

The Source Code files are provided at iText GitHub site.

You can compile it to generate your JAR file, using pom.xml as the build configuration file.

The source code of itextpdf-5.5.14.jar is provided below:

⏎ com/itextpdf/text/pdf/BarcodeQRCode.java

/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2020 iText Group NV
 * Authors: Bruno Lowagie, Paulo Soares, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * a covered work must retain the producer line in every PDF that is created
 * or manipulated using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
 * disclosing the source code of your own applications.
 * These activities include: offering paid services to customers as an ASP,
 * serving PDFs on the fly in a web application, shipping iText with a closed
 * source product.
 *
 * For more information, please contact iText Software Corp. at this
 * address: sales@itextpdf.com
 */
package com.itextpdf.text.pdf;

import com.itextpdf.text.*;
import com.itextpdf.text.pdf.qrcode.EncodeHintType;
import com.itextpdf.text.pdf.qrcode.WriterException;
import com.itextpdf.text.pdf.qrcode.ByteMatrix;
import com.itextpdf.text.pdf.qrcode.QRCodeWriter;
import com.itextpdf.text.pdf.codec.CCITTG4Encoder;
import java.util.Map;

/**
 * A QRCode implementation based on the zxing code.
 * @author Paulo Soares
 * @since 5.0.2
 */
public class BarcodeQRCode {
    ByteMatrix bm;

    /**
     * Creates the QR barcode. The barcode is always created with the smallest possible size and is then stretched
     * to the width and height given. Set the width and height to 1 to get an unscaled barcode.
     * @param content the text to be encoded
     * @param width the barcode width
     * @param height the barcode height
     * @param hints modifiers to change the way the barcode is create. They can be EncodeHintType.ERROR_CORRECTION
     * and EncodeHintType.CHARACTER_SET. For EncodeHintType.ERROR_CORRECTION the values can be ErrorCorrectionLevel.L, M, Q, H.
     * For EncodeHintType.CHARACTER_SET the values are strings and can be Cp437, Shift_JIS and ISO-8859-1 to ISO-8859-16.
     * You can also use UTF-8, but correct behaviour is not guaranteed as Unicode is not supported in QRCodes.
     * The default value is ISO-8859-1.
     * @throws WriterException
     */
    public BarcodeQRCode(String content, int width, int height, Map<EncodeHintType,Object> hints) {
        try {
            QRCodeWriter qc = new QRCodeWriter();
            bm = qc.encode(content, width, height, hints);
        }
        catch (WriterException ex) {
            throw new ExceptionConverter(ex);
        }
    }

    private byte[] getBitMatrix() {
        int width = bm.getWidth();
        int height = bm.getHeight();
        int stride = (width + 7) / 8;
        byte[] b = new byte[stride * height];
        byte[][] mt = bm.getArray();
        for (int y = 0; y < height; ++y) {
            byte[] line = mt[y];
            for (int x = 0; x < width; ++x) {
                if (line[x] != 0) {
                    int offset = stride * y + x / 8;
                    b[offset] |= (byte)(0x80 >> (x % 8));
                }
            }
        }
        return b;
    }

    /** Gets an <CODE>Image</CODE> with the barcode.
     * @return the barcode <CODE>Image</CODE>
     * @throws BadElementException on error
     */
    public Image getImage() throws BadElementException {
        byte[] b = getBitMatrix();
        byte g4[] = CCITTG4Encoder.compress(b, bm.getWidth(), bm.getHeight());
        return Image.getInstance(bm.getWidth(), bm.getHeight(), false, Image.CCITTG4, Image.CCITT_BLACKIS1, g4, null);
    }

    // AWT related methods (remove this if you port to Android / GAE)

    /** Creates a <CODE>java.awt.Image</CODE>.
     * @param foreground the color of the bars
     * @param background the color of the background
     * @return the image
     */
    public java.awt.Image createAwtImage(java.awt.Color foreground, java.awt.Color background) {
        int f = foreground.getRGB();
        int g = background.getRGB();
        java.awt.Canvas canvas = new java.awt.Canvas();

        int width = bm.getWidth();
        int height = bm.getHeight();
        int pix[] = new int[width * height];
        byte[][] mt = bm.getArray();
        for (int y = 0; y < height; ++y) {
            byte[] line = mt[y];
            for (int x = 0; x < width; ++x) {
                pix[y * width + x] = line[x] == 0 ? f : g;
            }
        }

        java.awt.Image img = canvas.createImage(new java.awt.image.MemoryImageSource(width, height, pix, 0, width));
        return img;
    }

    public void placeBarcode(PdfContentByte cb, BaseColor foreground, float moduleSide) {
        int width = bm.getWidth();
        int height = bm.getHeight();
        byte[][] mt = bm.getArray();

        cb.setColorFill(foreground);

        for (int y = 0; y < height; ++y) {
            byte[] line = mt[y];
            for (int x = 0; x < width; ++x) {
                if (line[x] == 0) {
                    cb.rectangle(x * moduleSide, (height - y - 1) * moduleSide, moduleSide, moduleSide);
                }
            }
        }
        cb.fill();
    }

    /** Gets the size of the barcode grid. */
    public Rectangle getBarcodeSize() {
        return new Rectangle(0, 0, bm.getWidth(), bm.getHeight());
    }
}

⏎ com/itextpdf/text/pdf/BarcodeQRCode.java

Or download all of them as a single archive file:

File name: itextpdf-5.5.14-fyi.zip
File size: 2163839 bytes
Release date: 2009-10-09
Download 

⇒ iText-2.1.6.jar - iText, a JAVA-PDF library

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