631 lines
26 KiB
Java
631 lines
26 KiB
Java
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/* JPEGDecoder.java --
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Copyright (C) 2006 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package gnu.javax.imageio.jpeg;
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import java.io.IOException;
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import java.nio.ByteOrder;
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import javax.imageio.*;
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import javax.imageio.plugins.jpeg.JPEGHuffmanTable;
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import javax.imageio.plugins.jpeg.JPEGQTable;
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import javax.imageio.spi.*;
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import javax.imageio.metadata.*;
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import javax.imageio.stream.ImageInputStream;
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import java.util.ArrayList;
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import java.util.Hashtable;
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import java.util.Iterator;
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import java.awt.Point;
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import java.awt.Transparency;
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import java.awt.color.ColorSpace;
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import java.awt.image.BufferedImage;
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import java.awt.image.ComponentColorModel;
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import java.awt.image.DataBuffer;
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import java.awt.image.Raster;
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import java.awt.image.WritableRaster;
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public class JPEGDecoder
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{
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byte majorVersion;
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byte minorVersion;
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byte units;
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short Xdensity;
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short Ydensity;
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byte Xthumbnail;
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byte Ythumbnail;
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byte[] thumbnail;
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BufferedImage image;
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int width;
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int height;
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byte marker;
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/**
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* This decoder expects JFIF 1.02 encoding.
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*/
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public static final byte MAJOR_VERSION = (byte) 1;
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public static final byte MINOR_VERSION = (byte) 2;
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/**
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* The length of the JFIF field not including thumbnail data.
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*/
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public static final short JFIF_FIXED_LENGTH = 16;
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/**
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* The length of the JFIF extension field not including extension
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* data.
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*/
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public static final short JFXX_FIXED_LENGTH = 8;
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private JPEGImageInputStream jpegStream;
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ArrayList jpegFrames = new ArrayList();
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JPEGHuffmanTable[] dcTables = new JPEGHuffmanTable[4];
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JPEGHuffmanTable[] acTables = new JPEGHuffmanTable[4];
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JPEGQTable[] qTables = new JPEGQTable[4];
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public int getHeight()
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{
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return height;
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}
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public int getWidth()
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{
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return width;
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}
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public JPEGDecoder(ImageInputStream in)
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throws IOException, JPEGException
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{
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jpegStream = new JPEGImageInputStream(in);
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jpegStream.setByteOrder(ByteOrder.LITTLE_ENDIAN);
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if (jpegStream.findNextMarker() != JPEGMarker.SOI)
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throw new JPEGException("Failed to find SOI marker.");
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if (jpegStream.findNextMarker() != JPEGMarker.APP0)
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throw new JPEGException("Failed to find APP0 marker.");
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int length = jpegStream.readShort();
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if (!(length >= JFIF_FIXED_LENGTH))
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throw new JPEGException("Failed to find JFIF field.");
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byte[] identifier = new byte[5];
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jpegStream.read(identifier);
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if (identifier[0] != JPEGMarker.JFIF_J
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|| identifier[1] != JPEGMarker.JFIF_F
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|| identifier[2] != JPEGMarker.JFIF_I
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|| identifier[3] != JPEGMarker.JFIF_F
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|| identifier[4] != JPEGMarker.X00)
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throw new JPEGException("Failed to read JFIF identifier.");
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majorVersion = jpegStream.readByte();
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minorVersion = jpegStream.readByte();
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if (majorVersion != MAJOR_VERSION
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|| (majorVersion == MAJOR_VERSION
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&& minorVersion < MINOR_VERSION))
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throw new JPEGException("Unsupported JFIF version.");
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units = jpegStream.readByte();
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if (units > (byte) 2)
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throw new JPEGException("Units field is out of range.");
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Xdensity = jpegStream.readShort();
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Ydensity = jpegStream.readShort();
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Xthumbnail = jpegStream.readByte();
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Ythumbnail = jpegStream.readByte();
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// 3 * for RGB data
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int thumbnailLength = 3 * Xthumbnail * Ythumbnail;
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if (length > JFIF_FIXED_LENGTH
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&& thumbnailLength != length - JFIF_FIXED_LENGTH)
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throw new JPEGException("Invalid length, Xthumbnail"
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+ " or Ythumbnail field.");
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if (thumbnailLength > 0)
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{
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thumbnail = new byte[thumbnailLength];
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if (jpegStream.read(thumbnail) != thumbnailLength)
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throw new IOException("Failed to read thumbnail.");
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}
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}
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public void decode()
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throws IOException
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{
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System.out.println ("DECODE!!!");
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// The frames in this jpeg are loaded into a list. There is
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// usually just one frame except in heirarchial progression where
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// there are multiple frames.
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JPEGFrame frame = null;
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// The restart interval defines how many MCU's we should have
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// between the 8-modulo restart marker. The restart markers allow
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// us to tell whether or not our decoding process is working
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// correctly, also if there is corruption in the image we can
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// recover with these restart intervals. (See RSTm DRI).
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int resetInterval = 0;
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// The JPEGDecoder constructor parses the JFIF field. At this
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// point jpegStream points to the first byte after the JFIF field.
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// Find the first marker after the JFIF field.
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byte marker = jpegStream.findNextMarker();
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// Check for a JFIF extension field directly following the JFIF
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// header and advance the current marker to the next marker in the
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// stream, if necessary.
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decodeJFIFExtension();
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// Loop through until there are no more markers to read in, at
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// that point everything is loaded into the jpegFrames array and
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// can be processed.
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while (true)
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{
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switch (marker)
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{
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// APPn Application Reserved Information - Just throw this
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// information away because we wont be using it.
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case JPEGMarker.APP0:
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case JPEGMarker.APP1:
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case JPEGMarker.APP2:
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case JPEGMarker.APP3:
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case JPEGMarker.APP4:
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case JPEGMarker.APP5:
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case JPEGMarker.APP6:
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case JPEGMarker.APP7:
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case JPEGMarker.APP8:
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case JPEGMarker.APP9:
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case JPEGMarker.APP10:
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case JPEGMarker.APP11:
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case JPEGMarker.APP12:
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case JPEGMarker.APP13:
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case JPEGMarker.APP14:
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case JPEGMarker.APP15:
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jpegStream.skipBytes(jpegStream.readShort() - 2);
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break;
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case JPEGMarker.SOF0:
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// SOFn Start of Frame Marker, Baseline DCT - This is the start
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// of the frame header that defines certain variables that will
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// be carried out through the rest of the encoding. Multiple
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// frames are used in a heirarchiel system, however most JPEG's
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// only contain a single frame.
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jpegFrames.add(new JPEGFrame());
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frame = (JPEGFrame) jpegFrames.get(jpegFrames.size() - 1);
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// Skip the frame length.
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jpegStream.readShort();
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// Bits percision, either 8 or 12.
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frame.setPrecision(jpegStream.readByte());
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// Scan lines = to the height of the frame.
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frame.setScanLines(jpegStream.readShort());
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// Scan samples per line = to the width of the frame.
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frame.setSamplesPerLine(jpegStream.readShort());
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// Number of Color Components (or channels).
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frame.setComponentCount(jpegStream.readByte());
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// Set the color mode for this frame, so far only 2 color
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// modes are supported.
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if (frame.getComponentCount() == 1)
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frame.setColorMode(JPEGFrame.JPEG_COLOR_GRAY);
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else
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frame.setColorMode(JPEGFrame.JPEG_COLOR_YCbCr);
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// Add all of the necessary components to the frame.
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for (int i = 0; i < frame.getComponentCount(); i++)
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frame.addComponent(jpegStream.readByte(), jpegStream.readByte(),
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jpegStream.readByte());
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break;
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case JPEGMarker.SOF2:
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jpegFrames.add(new JPEGFrame());
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frame = (JPEGFrame) jpegFrames.get(jpegFrames.size() - 1);
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// Skip the frame length.
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jpegStream.readShort();
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// Bits percision, either 8 or 12.
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frame.setPrecision(jpegStream.readByte());
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// Scan lines = to the height of the frame.
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frame.setScanLines(jpegStream.readShort());
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// Scan samples per line = to the width of the frame.
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frame.setSamplesPerLine(jpegStream.readShort());
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// Number of Color Components (or channels).
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frame.setComponentCount(jpegStream.readByte());
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// Set the color mode for this frame, so far only 2 color
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// modes are supported.
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if (frame.getComponentCount() == 1)
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frame.setColorMode(JPEGFrame.JPEG_COLOR_GRAY);
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else
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frame.setColorMode(JPEGFrame.JPEG_COLOR_YCbCr);
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// Add all of the necessary components to the frame.
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for (int i = 0; i < frame.getComponentCount(); i++)
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frame.addComponent(jpegStream.readByte(), jpegStream.readByte(),
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jpegStream.readByte());
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break;
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case JPEGMarker.DHT:
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// DHT non-SOF Marker - Huffman Table is required for decoding
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// the JPEG stream, when we receive a marker we load in first
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// the table length (16 bits), the table class (4 bits), table
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// identifier (4 bits), then we load in 16 bytes and each byte
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// represents the count of bytes to load in for each of the 16
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// bytes. We load this into an array to use later and move on 4
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// huffman tables can only be used in an image.
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int huffmanLength = (jpegStream.readShort() - 2);
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// Keep looping until we are out of length.
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int index = huffmanLength;
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// Multiple tables may be defined within a DHT marker. This
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// will keep reading until there are no tables left, most
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// of the time there are just one tables.
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while (index > 0)
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{
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// Read the identifier information and class
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// information about the Huffman table, then read the
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// 16 byte codelength in and read in the Huffman values
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// and put it into table info.
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byte huffmanInfo = jpegStream.readByte();
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byte tableClass = (byte) (huffmanInfo >> 4);
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byte huffmanIndex = (byte) (huffmanInfo & 0x0f);
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short[] codeLength = new short[16];
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jpegStream.readFully(codeLength, 0, codeLength.length);
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int huffmanValueLen = 0;
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for (int i = 0; i < 16; i++)
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huffmanValueLen += codeLength[i];
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index -= (huffmanValueLen + 17);
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short[] huffmanVal = new short[huffmanValueLen];
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for (int i = 0; i < huffmanVal.length; i++)
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huffmanVal[i] = jpegStream.readByte();
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// Assign DC Huffman Table.
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if (tableClass == HuffmanTable.JPEG_DC_TABLE)
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dcTables[(int) huffmanIndex] = new JPEGHuffmanTable(codeLength,
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huffmanVal);
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// Assign AC Huffman Table.
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else if (tableClass == HuffmanTable.JPEG_AC_TABLE)
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acTables[(int) huffmanIndex] = new JPEGHuffmanTable(codeLength,
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huffmanVal);
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}
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break;
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case JPEGMarker.DQT:
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// DQT non-SOF Marker - This defines the quantization
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// coeffecients, this allows us to figure out the quality of
|
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// compression and unencode the data. The data is loaded and
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// then stored in to an array.
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short quantizationLength = (short) (jpegStream.readShort() - 2);
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for (int j = 0; j < quantizationLength / 65; j++)
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{
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byte quantSpecs = jpegStream.readByte();
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int[] quantData = new int[64];
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if ((byte) (quantSpecs >> 4) == 0)
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// Precision 8 bit.
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{
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for (int i = 0; i < 64; i++)
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quantData[i] = jpegStream.readByte();
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}
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else if ((byte) (quantSpecs >> 4) == 1)
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// Precision 16 bit.
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{
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for (int i = 0; i < 64; i++)
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quantData[i] = jpegStream.readShort();
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}
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qTables[(int) (quantSpecs & 0x0f)] = new JPEGQTable (quantData);
|
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}
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break;
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case JPEGMarker.SOS:
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// SOS non-SOF Marker - Start Of Scan Marker, this is where the
|
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// actual data is stored in a interlaced or non-interlaced with
|
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// from 1-4 components of color data, if three components most
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||
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// likely a YCrCb model, this is a fairly complex process.
|
||
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// Read in the scan length.
|
||
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jpegStream.readShort();
|
||
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// Number of components in the scan.
|
||
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byte numberOfComponents = jpegStream.readByte();
|
||
|
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byte[] componentSelector = new byte[numberOfComponents];
|
||
|
|
for (int i = 0; i < numberOfComponents; i++)
|
||
|
|
{
|
||
|
|
// Component ID, packed byte containing the Id for the
|
||
|
|
// AC table and DC table.
|
||
|
|
byte componentID = jpegStream.readByte();
|
||
|
|
byte tableInfo = jpegStream.readByte();
|
||
|
|
frame.setHuffmanTables(componentID,
|
||
|
|
acTables[(byte) (tableInfo >> 4)],
|
||
|
|
dcTables[(byte) (tableInfo & 0x0f)]);
|
||
|
|
componentSelector[i] = componentID;
|
||
|
|
}
|
||
|
|
byte startSpectralSelection = jpegStream.readByte();
|
||
|
|
byte endSpectralSelection = jpegStream.readByte();
|
||
|
|
byte successiveApproximation = jpegStream.readByte();
|
||
|
|
|
||
|
|
int mcuIndex = 0;
|
||
|
|
int mcuTotalIndex = 0;
|
||
|
|
// This loops through until a MarkerTagFound exception is
|
||
|
|
// found, if the marker tag is a RST (Restart Marker) it
|
||
|
|
// simply skips it and moves on this system does not handle
|
||
|
|
// corrupt data streams very well, it could be improved by
|
||
|
|
// handling misplaced restart markers.
|
||
|
|
while (true)
|
||
|
|
{
|
||
|
|
try
|
||
|
|
{
|
||
|
|
// Loop though capturing MCU, instruct each
|
||
|
|
// component to read in its necessary count, for
|
||
|
|
// scaling factors the components automatically
|
||
|
|
// read in how much they need
|
||
|
|
for (int compIndex = 0; compIndex < numberOfComponents; compIndex++)
|
||
|
|
{
|
||
|
|
JPEGComponent comp = (JPEGComponent) frame.components.getComponentByID(componentSelector[compIndex]);
|
||
|
|
comp.readComponentMCU(jpegStream);
|
||
|
|
}
|
||
|
|
mcuIndex++;
|
||
|
|
mcuTotalIndex++;
|
||
|
|
}
|
||
|
|
// We've found a marker, see if the marker is a restart
|
||
|
|
// marker or just the next marker in the stream. If
|
||
|
|
// it's the next marker in the stream break out of the
|
||
|
|
// while loop, if it's just a restart marker skip it
|
||
|
|
catch (JPEGMarkerFoundException bse)
|
||
|
|
{
|
||
|
|
// Handle JPEG Restart Markers, this is where the
|
||
|
|
// count of MCU's per interval is compared with
|
||
|
|
// the count actually obtained, if it's short then
|
||
|
|
// pad on some MCU's ONLY for components that are
|
||
|
|
// greater than one. Also restart the DC prediction
|
||
|
|
// to zero.
|
||
|
|
if (marker == JPEGMarker.RST0
|
||
|
|
|| marker == JPEGMarker.RST1
|
||
|
|
|| marker == JPEGMarker.RST2
|
||
|
|
|| marker == JPEGMarker.RST3
|
||
|
|
|| marker == JPEGMarker.RST4
|
||
|
|
|| marker == JPEGMarker.RST5
|
||
|
|
|| marker == JPEGMarker.RST6
|
||
|
|
|| marker == JPEGMarker.RST7)
|
||
|
|
{
|
||
|
|
for (int compIndex = 0; compIndex < numberOfComponents; compIndex++)
|
||
|
|
{
|
||
|
|
JPEGComponent comp = (JPEGComponent) frame.components.getComponentByID(componentSelector[compIndex]);
|
||
|
|
if (compIndex > 1)
|
||
|
|
comp.padMCU(mcuTotalIndex, resetInterval - mcuIndex);
|
||
|
|
comp.resetInterval();
|
||
|
|
}
|
||
|
|
mcuTotalIndex += (resetInterval - mcuIndex);
|
||
|
|
mcuIndex = 0;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
// We're at the end of our scan, exit out.
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case JPEGMarker.DRI:
|
||
|
|
// DRI - This defines the restart interval, if we have a
|
||
|
|
// restart interval when we reach our restart modulo calculate
|
||
|
|
// whether the count of MCU's specified in the restart
|
||
|
|
// interval have been reached, if they havent then pad with
|
||
|
|
// whatever MCU was last used, this is supposed to be a form of
|
||
|
|
// error recovery but it turns out that some JPEG encoders
|
||
|
|
// purposely cause missing MCU's on repeating MCU's to compress
|
||
|
|
// data even more (even though it adds an extra layer of
|
||
|
|
// complexity.. But since when is JPEG easy?
|
||
|
|
jpegStream.skipBytes(2);
|
||
|
|
resetInterval = jpegStream.readShort();
|
||
|
|
break;
|
||
|
|
case JPEGMarker.COM:
|
||
|
|
// COM - This is a comment that was inserted into the JPEG, we
|
||
|
|
// simply skip over the comment because it's really of no
|
||
|
|
// importance, usually contains a verbal description of the
|
||
|
|
// application or author who created the JPEG.
|
||
|
|
jpegStream.skipBytes(jpegStream.readShort() - 2);
|
||
|
|
break;
|
||
|
|
case JPEGMarker.DNL:
|
||
|
|
// DNL - This sets the height of the image. This is the Define
|
||
|
|
// Number Lines for the image, I'm not sure exactly why we need
|
||
|
|
// this but, whatever we'll abide.
|
||
|
|
frame.setScanLines(jpegStream.readShort());
|
||
|
|
break;
|
||
|
|
case JPEGMarker.EOI:
|
||
|
|
// EOI - End of Image, this processes the frames and turns the
|
||
|
|
// frames into a buffered image.
|
||
|
|
|
||
|
|
if (jpegFrames.size() == 0)
|
||
|
|
{
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
else if (jpegFrames.size() == 1)
|
||
|
|
{
|
||
|
|
// Only one frame, JPEG Non-Heirarchial Frame.
|
||
|
|
|
||
|
|
DCT myDCT = new DCT();
|
||
|
|
WritableRaster raster =
|
||
|
|
Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE,
|
||
|
|
frame.width,
|
||
|
|
frame.height,
|
||
|
|
frame.getComponentCount(),
|
||
|
|
new Point(0, 0));
|
||
|
|
|
||
|
|
// Unencode the data.
|
||
|
|
for (int i = 0; i < frame.getComponentCount(); i++)
|
||
|
|
{
|
||
|
|
JPEGComponent comp =
|
||
|
|
(JPEGComponent) frame.components.get(i);
|
||
|
|
comp.setQuantizationTable(qTables[comp.quant_id].getTable());
|
||
|
|
comp.quantitizeData();
|
||
|
|
comp.idctData(myDCT);
|
||
|
|
}
|
||
|
|
// Scale the image and write the data to the raster.
|
||
|
|
for (int i = 0; i < frame.getComponentCount(); i++)
|
||
|
|
{
|
||
|
|
JPEGComponent comp = (JPEGComponent) frame.components.get(i);
|
||
|
|
comp.scaleByFactors();
|
||
|
|
comp.writeData(raster, i);
|
||
|
|
// Ensure garbage collection.
|
||
|
|
comp = null;
|
||
|
|
}
|
||
|
|
// Grayscale Color Image (1 Component).
|
||
|
|
if (frame.getComponentCount() == 1)
|
||
|
|
{
|
||
|
|
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
|
||
|
|
ComponentColorModel ccm =
|
||
|
|
new ComponentColorModel(cs, false, false,
|
||
|
|
Transparency.OPAQUE,
|
||
|
|
DataBuffer.TYPE_BYTE);
|
||
|
|
image = new BufferedImage(ccm, raster, false,
|
||
|
|
new Hashtable());
|
||
|
|
}
|
||
|
|
// YCbCr Color Image (3 Components).
|
||
|
|
else if (frame.getComponentCount() == 3)
|
||
|
|
{
|
||
|
|
ComponentColorModel ccm =
|
||
|
|
new ComponentColorModel(new YCbCr_ColorSpace(), false,
|
||
|
|
false, Transparency.OPAQUE,
|
||
|
|
DataBuffer.TYPE_BYTE);
|
||
|
|
image = new BufferedImage(ccm, raster, false,
|
||
|
|
new Hashtable());
|
||
|
|
}
|
||
|
|
// Possibly CMYK or RGBA ?
|
||
|
|
else
|
||
|
|
{
|
||
|
|
throw new JPEGException("Unsupported Color Mode: 4 "
|
||
|
|
+ "Component Color Mode found.");
|
||
|
|
}
|
||
|
|
height = frame.height;
|
||
|
|
width = frame.width;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
//JPEG Heirarchial Frame (progressive or baseline).
|
||
|
|
throw new JPEGException("Unsupported Codec Type:"
|
||
|
|
+ " Hierarchial JPEG");
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case JPEGMarker.SOF1:
|
||
|
|
// ERROR - If we encounter any of the following marker codes
|
||
|
|
// error out with a codec exception, progressive, heirarchial,
|
||
|
|
// differential, arithmetic, lossless JPEG's are not supported.
|
||
|
|
// This is where enhancements can be made for future versions.
|
||
|
|
// Thankfully 99% of all JPEG's are baseline DCT.
|
||
|
|
throw new JPEGException("Unsupported Codec Type: Extended "
|
||
|
|
+ "Sequential DCT JPEG's Not-Supported");
|
||
|
|
//case JPEGMarker.SOF2:
|
||
|
|
// throw new JPEGException("Unsupported Codec Type: Progressive DCT JPEG's Not-Supported");
|
||
|
|
case JPEGMarker.SOF3:
|
||
|
|
throw new JPEGException("Unsupported Codec Type:"
|
||
|
|
+ " Lossless (sequential)");
|
||
|
|
case JPEGMarker.SOF5:
|
||
|
|
throw new JPEGException("Unsupported Codec Type:"
|
||
|
|
+ " Differential sequential DCT");
|
||
|
|
case JPEGMarker.SOF6:
|
||
|
|
throw new JPEGException("Unsupported Codec Type:"
|
||
|
|
+ " Differential progressive DCT");
|
||
|
|
case JPEGMarker.SOF7:
|
||
|
|
throw new JPEGException("Unsupported Codec Type:"
|
||
|
|
+ " Differential lossless");
|
||
|
|
case JPEGMarker.SOF9:
|
||
|
|
case JPEGMarker.SOF10:
|
||
|
|
case JPEGMarker.SOF11:
|
||
|
|
case JPEGMarker.SOF13:
|
||
|
|
case JPEGMarker.SOF14:
|
||
|
|
case JPEGMarker.SOF15:
|
||
|
|
throw new JPEGException("Unsupported Codec Type:"
|
||
|
|
+ " Arithmetic Coding Frame");
|
||
|
|
default:
|
||
|
|
// Unknown marker found, ignore it.
|
||
|
|
}
|
||
|
|
marker = jpegStream.findNextMarker();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// If the current marker is APP0, tries to decode a JFIF extension
|
||
|
|
// and advances the current marker to the next marker in the stream.
|
||
|
|
private void decodeJFIFExtension() throws IOException
|
||
|
|
{
|
||
|
|
if (marker == JPEGMarker.APP0)
|
||
|
|
{
|
||
|
|
int length = jpegStream.readShort();
|
||
|
|
|
||
|
|
if (length >= JFXX_FIXED_LENGTH)
|
||
|
|
{
|
||
|
|
byte[] identifier = new byte[5];
|
||
|
|
jpegStream.read(identifier);
|
||
|
|
if (identifier[0] != JPEGMarker.JFIF_J
|
||
|
|
|| identifier[1] != JPEGMarker.JFIF_F
|
||
|
|
|| identifier[2] != JPEGMarker.JFIF_X
|
||
|
|
|| identifier[3] != JPEGMarker.JFIF_X
|
||
|
|
|| identifier[4] != JPEGMarker.X00)
|
||
|
|
// Not a JFXX field. Ignore it and continue.
|
||
|
|
jpegStream.skipBytes(length - 7);
|
||
|
|
else
|
||
|
|
{
|
||
|
|
byte extension_code = jpegStream.readByte();
|
||
|
|
|
||
|
|
switch (extension_code)
|
||
|
|
{
|
||
|
|
case JPEGMarker.JFXX_JPEG:
|
||
|
|
// FIXME: add support for JFIF Extension:
|
||
|
|
// Thumbnail coded using JPEG.
|
||
|
|
jpegStream.skipBytes(length - 8);
|
||
|
|
case JPEGMarker.JFXX_ONE_BPP:
|
||
|
|
// FIXME: add support for JFIF Extension:
|
||
|
|
// Thumbnail stored using 1 byte/pixel.
|
||
|
|
jpegStream.skipBytes(length - 8);
|
||
|
|
case JPEGMarker.JFXX_THREE_BPP:
|
||
|
|
// FIXME: add support for JFIF Extension:
|
||
|
|
// Thumbnail stored using 3 bytes/pixel.
|
||
|
|
jpegStream.skipBytes(length - 8);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
// Unknown APP0 marker. Ignore it and continue.
|
||
|
|
jpegStream.skipBytes(length - 2);
|
||
|
|
}
|
||
|
|
marker = jpegStream.findNextMarker();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
public BufferedImage getImage()
|
||
|
|
{
|
||
|
|
return image;
|
||
|
|
}
|
||
|
|
}
|