ReadPNGWithNoTextInTEXTChunk.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/*
 * @test
 * @bug     8212116
 * @summary Test verifies that PNGImageReader doesn't throw IIOException
 *          when reading a tEXt chunk having no text.
 * @run     main ReadPNGWithNoTextInTEXTChunk
 */

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.Color;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Iterator;
import javax.imageio.ImageTypeSpecifier;
import javax.imageio.ImageWriter;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.ImageWriteParam;
import javax.imageio.metadata.IIOInvalidTreeException;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataNode;
import javax.imageio.stream.ImageOutputStream;
import javax.imageio.stream.ImageInputStream;
import javax.imageio.IIOImage;

public class ReadPNGWithNoTextInTEXTChunk {

    private static BufferedImage img;
    private static ImageWriter writer;
    private static ImageWriteParam param;
    private static IIOMetadata metadata;
    private static byte[] imageByteArray;

    private static void initialize(int type) {
        int width = 1;
        int height = 1;
        img = new BufferedImage(width, height, type);
        Graphics2D g2D = img.createGraphics();
        g2D.setColor(new Color(255, 255, 255));
        g2D.fillRect(0, 0, width, width);
        g2D.dispose();

        Iterator<ImageWriter> iterWriter =
                ImageIO.getImageWritersBySuffix("png");
        writer = iterWriter.next();

        param = writer.getDefaultWriteParam();
        ImageTypeSpecifier specifier =
                ImageTypeSpecifier.
                        createFromBufferedImageType(type);
        metadata = writer.getDefaultImageMetadata(specifier, param);
    }

    private static void createTEXTNode()
            throws IIOInvalidTreeException {
        IIOMetadataNode tEXt_Entry = new IIOMetadataNode("tEXtEntry");
        tEXt_Entry.setAttribute("keyword", "Author");
        tEXt_Entry.setAttribute("value", "");

        IIOMetadataNode tEXt = new IIOMetadataNode("tEXt");
        tEXt.appendChild(tEXt_Entry);
        IIOMetadataNode root = new IIOMetadataNode("javax_imageio_png_1.0");
        root.appendChild(tEXt);
        metadata.mergeTree("javax_imageio_png_1.0", root);
    }

    private static void writeImage() throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ImageOutputStream ios = ImageIO.createImageOutputStream(baos);
        writer.setOutput(ios);
        writer.write(metadata, new IIOImage(img, null, metadata), param);
        writer.dispose();

        baos.flush();
        imageByteArray = baos.toByteArray();
        baos.close();
    }

    private static void readPNGTEXTChunk() throws IOException {
        initialize(BufferedImage.TYPE_BYTE_GRAY);
        // Create tEXt node with text length 0
        createTEXTNode();

        writeImage();

        ByteArrayInputStream bais = new ByteArrayInputStream( imageByteArray );
        ImageInputStream input= ImageIO.createImageInputStream(bais);
        Iterator iter = ImageIO.getImageReaders(input);
        ImageReader reader = (ImageReader) iter.next();
        reader.setInput(input, false, false);
        BufferedImage image = reader.read(0, reader.getDefaultReadParam());
        input.close();
        bais.close();
    }

    public static void main(String[] args) throws IOException {

        // read PNG image where tEXt chunk's text length is 0
        readPNGTEXTChunk();
    }
}