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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.pdmodel.graphics.predictor;
/**
*
*
* In an Uptimum encoded image, each line takes up width*bpp+1 bytes. The first
* byte holds a number that signifies which algorithm encoded the line.
*
* @author [email protected]
* @version $Revision: 1.1 $
*/
public class Optimum extends PredictorAlgorithm
{
/**
* {@inheritDoc}
*/
public void checkBufsiz(byte[] filtered, byte[] raw)
{
if (filtered.length != (getWidth() * getBpp() + 1) * getHeight())
{
throw new IllegalArgumentException(
"filtered.length != (width*bpp + 1) * height, "
+ filtered.length + " "
+ (getWidth() * getBpp() + 1) * getHeight()
+ "w,h,bpp=" + getWidth() + "," + getHeight() + ","
+ getBpp());
}
if (raw.length != getWidth() * getHeight() * getBpp())
{
throw new IllegalArgumentException(
"raw.length != width * height * bpp, raw.length="
+ raw.length + " w,h,bpp=" + getWidth() + ","
+ getHeight() + "," + getBpp());
}
}
/**
* {@inheritDoc}
*/
public void encodeLine(byte[] src, byte[] dest, int srcDy, int srcOffset,
int destDy, int destOffset)
{
throw new UnsupportedOperationException("encodeLine");
}
/**
* {@inheritDoc}
*/
public void decodeLine(byte[] src, byte[] dest, int srcDy, int srcOffset,
int destDy, int destOffset)
{
throw new UnsupportedOperationException("decodeLine");
}
/**
* {@inheritDoc}
*/
public void encode(byte[] src, byte[] dest)
{
checkBufsiz(dest, src);
throw new UnsupportedOperationException("encode");
}
/**
* Filter indexed by byte code.
*/
PredictorAlgorithm[] filter = { new None(), new Sub(), new Up(), new Average(),
new Paeth() };
/**
* {@inheritDoc}
*/
public void setBpp(int bpp)
{
super.setBpp(bpp);
for (int i = 0; i < filter.length; i++)
{
filter[i].setBpp(bpp);
}
}
/**
* {@inheritDoc}
*/
public void setHeight(int height)
{
super.setHeight(height);
for (int i = 0; i < filter.length; i++)
{
filter[i].setHeight(height);
}
}
/**
* {@inheritDoc}
*/
public void setWidth(int width)
{
super.setWidth(width);
for (int i = 0; i < filter.length; i++)
{
filter[i].setWidth(width);
}
}
/**
* {@inheritDoc}
*/
public void decode(byte[] src, byte[] dest)
{
checkBufsiz(src, dest);
int bpl = getWidth() * getBpp();
int srcDy = bpl + 1;
for (int y = 0; y < getHeight(); y++)
{
PredictorAlgorithm f = filter[src[y * srcDy]];
int srcOffset = y * srcDy + 1;
f.decodeLine(src, dest, srcDy, srcOffset, bpl, y * bpl);
}
}
}