/*
* 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 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.COSDictionary;
import org.apache.pdfbox.cos.COSInteger;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSStream;
/**
* Decompresses data encoded using the JBIG2 standard, reproducing the original
* monochrome (1 bit per pixel) image data (or an approximation of that data).
*
* Requires a JBIG2 plugin for Java Image I/O to be installed. A known working
* plug-in is <a href="http://code.google.com/p/jbig2-imageio/">jbig2-imageio</a>
* which is available under the GPL v3 license.
*
* @author Timo Boehme
*/
final class JBIG2Filter extends Filter
{
private static final Log LOG = LogFactory.getLog(JBIG2Filter.class);
@Override
public final DecodeResult decode(InputStream encoded, OutputStream decoded,
COSDictionary parameters, int index) throws IOException
{
ImageReader reader = findImageReader("JBIG2", "jbig2-imageio is not installed");
DecodeResult result = new DecodeResult(new COSDictionary());
result.getParameters().addAll(parameters);
COSInteger bits = (COSInteger) parameters.getDictionaryObject(COSName.BITS_PER_COMPONENT);
COSDictionary params = (COSDictionary) parameters.getDictionaryObject(COSName.DECODE_PARMS);
COSStream globals = null;
if (params != null)
{
globals = (COSStream) params.getDictionaryObject(COSName.JBIG2_GLOBALS);
}
ImageInputStream iis = null;
try
{
if (globals != null)
{
iis = ImageIO.createImageInputStream(
new SequenceInputStream(globals.getUnfilteredStream(), encoded));
reader.setInput(iis);
}
else
{
iis = ImageIO.createImageInputStream(encoded);
reader.setInput(iis);
}
BufferedImage image;
try
{
image = reader.read(0);
}
catch (Exception e)
{
// wrap and rethrow any exceptions
throw new IOException("Could not read JBIG2 image", e);
}
// I am assuming since JBIG2 is always black and white
// depending on your renderer this might or might be needed
if (image.getColorModel().getPixelSize() != bits.intValue())
{
if (bits.intValue() != 1)
{
LOG.warn("Attempting to handle a JBIG2 with more than 1-bit depth");
}
BufferedImage packedImage = new BufferedImage(image.getWidth(), image.getHeight(),
BufferedImage.TYPE_BYTE_BINARY);
Graphics graphics = packedImage.getGraphics();
graphics.drawImage(image, 0, 0, null);
graphics.dispose();
image = packedImage;
}
DataBuffer dBuf = image.getData().getDataBuffer();
if (dBuf.getDataType() == DataBuffer.TYPE_BYTE)
{
decoded.write(((DataBufferByte) dBuf).getData());
}
else
{
throw new IOException("Unexpected image buffer type");
}
}
finally
{
if (iis != null)
{
iis.close();
}
reader.dispose();
}
// repair missing color space
if (!parameters.containsKey(COSName.COLORSPACE))
{
result.getParameters().setName(COSName.COLORSPACE, COSName.DEVICEGRAY.getName());
}
return new DecodeResult(parameters);
}
@Override
protected final void encode(InputStream input, OutputStream encoded, COSDictionary parameters)
throws IOException
{
throw new UnsupportedOperationException("JBIG2 encoding not implemented");
}
}