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The Apache PDFBox library is an open source Java tool for working with PDF documents.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.pdfbox.filter;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferByte;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.SequenceInputStream;
import java.util.Iterator;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSStream;
/**
* Modeled on the JBIG2Decode filter.
*
* thanks to Timo Boehme
*/
public class JBIG2Filter implements Filter
{
/** Log instance. */
private static final Log LOG = LogFactory.getLog(JBIG2Filter.class);
/**
* Decode JBIG2 data using Java ImageIO library.
*
* {@inheritDoc}
*
*/
public void decode( InputStream compressedData, OutputStream result, COSDictionary options, int filterIndex )
throws IOException
{
/**
* A working JBIG2 ImageIO plugin is needed to decode JBIG2 encoded streams.
* The following is known to be working. It can't be bundled with PDFBox because of an incompatible license.
* http://code.google.com/p/jbig2-imageio/
*/
Iterator readers = ImageIO.getImageReadersByFormatName("JBIG2");
if (!readers.hasNext())
{
LOG.error( "Can't find an ImageIO plugin to decode the JBIG2 encoded datastream.");
return;
}
ImageReader reader = readers.next();
if (reader == null)
{
LOG.error( "ImageIO plugin to decode the JBIG2 encoded datastream is null.");
return;
}
COSBase decodeP = options.getDictionaryObject(COSName.DECODE_PARMS, COSName.DP);
COSDictionary decodeParms = null;
if (decodeP instanceof COSDictionary)
{
decodeParms = (COSDictionary) decodeP;
}
else if (decodeP instanceof COSArray)
{
decodeParms = (COSDictionary) ((COSArray) decodeP).getObject(filterIndex);
}
int bits = options.getInt(COSName.BITS_PER_COMPONENT, 1);
COSStream st = null;
if (decodeParms != null)
{
st = (COSStream) decodeParms.getDictionaryObject(COSName.JBIG2_GLOBALS);
}
if (st != null)
{
compressedData = new SequenceInputStream(st.getUnfilteredStream(),
compressedData);
}
ImageInputStream iis = ImageIO.createImageInputStream(compressedData);
reader.setInput(iis);
BufferedImage bi = reader.read(0, reader.getDefaultReadParam());
iis.close();
reader.dispose();
if ( bi != null )
{
// I am assuming since JBIG2 is always black and white
// depending on your renderer this might or might be needed
if (bi.getColorModel().getPixelSize() != bits)
{
if (bits != 1)
{
LOG.error("Do not know how to deal with JBIG2 with more than 1 bit");
return;
}
BufferedImage packedImage =
new BufferedImage(bi.getWidth(), bi.getHeight(), BufferedImage.TYPE_BYTE_BINARY);
Graphics graphics = packedImage.getGraphics();
graphics.drawImage(bi, 0, 0, null);
graphics.dispose();
bi = packedImage;
}
DataBuffer dBuf = bi.getData().getDataBuffer();
if ( dBuf.getDataType() == DataBuffer.TYPE_BYTE )
{
result.write( ( ( DataBufferByte ) dBuf ).getData() );
}
else
{
LOG.error( "Image data buffer not of type byte but type " + dBuf.getDataType() );
}
}
else
{
LOG.error( "Something went wrong when decoding the JBIG2 encoded datastream.");
}
}
/**
* {@inheritDoc}
*/
public void encode( InputStream rawData, OutputStream result, COSDictionary options, int filterIndex )
throws IOException
{
System.err.println( "Warning: JBIG2.encode is not implemented yet, skipping this stream." );
}
}