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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * 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).
 *
 * 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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 * questions.
 */

/*
 * @test
 * @bug     6788458
 * @summary Test verifies that PNGImageReader takes tRNS chunk values
 *          into consideration while reading non-indexed 16 bit PNG image.
 * @run     main Read16BitPNGWithTRNSChunk
 */

import java.awt.color.ColorSpace;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.ComponentColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferUShort;
import java.awt.image.WritableRaster;
import java.awt.image.Raster;
import java.awt.Color;
import java.awt.Transparency;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.Iterator;
import javax.imageio.ImageTypeSpecifier;
import javax.imageio.ImageWriter;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataNode;
import javax.imageio.stream.ImageOutputStream;
import javax.imageio.IIOImage;

public final class Read16BitPNGWithTRNSChunk {

    public static void main(String[] args) throws IOException {
        String dir = System.getProperty("test.src");
        String sep = System.getProperty("file.separator");
        String filePath = dir + sep;
        File directory = new File(filePath);
        File output = File.createTempFile("output", "png", directory);
        directory.delete();
        ImageOutputStream ios = ImageIO.createImageOutputStream(output);
        try {
            // Create 16 bit PNG image and fill it with white color
            int height = 50;
            int width = 50;
            int numBands = 3;
            int shortArrayLength = width * height * numBands;
            short[] pixelData = new short[shortArrayLength];
            for (int i = 0; i < shortArrayLength; i++) {
                pixelData[i] = (short)0xffff;
            }

            DataBuffer buffer = new DataBufferUShort(pixelData, shortArrayLength);

            int[] bandOffset = {0, 1 ,2};
            WritableRaster ras =
                Raster.createInterleavedRaster(buffer, width, height,
                    width * numBands, numBands, bandOffset, null);

            int nBits[] = {16, 16 ,16};
            ColorModel colorModel = new
            ComponentColorModel(ColorSpace.getInstance(ColorSpace.CS_sRGB),
                nBits, false, false, Transparency.OPAQUE,
                DataBuffer.TYPE_USHORT);
            BufferedImage img = new BufferedImage(colorModel, ras,
                false, null);

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

            ImageWriteParam param = writer.getDefaultWriteParam();
            ImageTypeSpecifier specifier =
                ImageTypeSpecifier.
                    createFromBufferedImageType(BufferedImage.TYPE_3BYTE_BGR);
            IIOMetadata metadata =
                writer.getDefaultImageMetadata(specifier, param);

            // Create tRNS node and merge it with default metadata
            IIOMetadataNode tRNS_rgb = new IIOMetadataNode("tRNS_RGB");
            tRNS_rgb.setAttribute("red", "65535");
            tRNS_rgb.setAttribute("green", "65535");
            tRNS_rgb.setAttribute("blue", "65535");

            IIOMetadataNode tRNS = new IIOMetadataNode("tRNS");
            tRNS.appendChild(tRNS_rgb);
            IIOMetadataNode root =
                new IIOMetadataNode("javax_imageio_png_1.0");
            root.appendChild(tRNS);

            metadata.mergeTree("javax_imageio_png_1.0", root);

            writer.setOutput(ios);

            writer.write(metadata, new IIOImage(img, null, metadata), param);

            // Read 16 bit PNG RGB image with tRNS chunk and verify
            BufferedImage display_img = ImageIO.read(output);
            Color c = new Color(display_img.getRGB(0, 0), true);
            if (c.getAlpha() != 0) {
                throw new RuntimeException("PNGImageReader is not using" +
                " transparent pixel information present in tRNS chunk");
            }
        } finally {
            ios.close();
            Files.delete(output.toPath());
        }

    }
}