/**
* Copyright (c) 2005, www.pdfbox.org
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of pdfbox; nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* http://www.pdfbox.org
*
*/
package org.pdfbox.pdmodel.graphics.predictor;
/**
* The up algorithm.
*
* Up(i,j) = Raw(i,j) - Raw(i,j-1)
*
* Raw(i,j) = Up(i,j) + Raw(i,j-1)
*
* @author xylifyx@yahoo.co.uk
* @version $Revision: 1.2 $
*/
public class Up extends PredictorAlgorithm
{
/**
* @see org.pdfbox.pdmodel.graphics.predictor.PredictorAlgorithm#encodeLine(byte[], byte[], int, int, int, int)
*/
public void encodeLine(byte[] src, byte[] dest, int srcDy, int srcOffset,
int destDy, int destOffset)
{
int bpl = getWidth()*getBpp();
// case: y = 0;
if (srcOffset - srcDy < 0)
{
if (0 < getHeight())
{
for (int x = 0; x < bpl; x++)
{
dest[destOffset + x] = src[srcOffset + x];
}
}
}
else
{
for (int x = 0; x < bpl; x++)
{
dest[destOffset + x] = (byte) (src[srcOffset + x] - src[srcOffset
+ x - srcDy]);
}
}
}
/**
* @see org.pdfbox.pdmodel.graphics.predictor.PredictorAlgorithm#decodeLine(byte[], byte[], int, int, int, int)
*/
public void decodeLine(byte[] src, byte[] dest, int srcDy, int srcOffset,
int destDy, int destOffset)
{
// case: y = 0;
int bpl = getWidth()*getBpp();
if (destOffset - destDy < 0)
{
if (0 < getHeight())
{
for (int x = 0; x < bpl; x++)
{
dest[destOffset + x] = src[srcOffset + x];
}
}
}
else
{
for (int x = 0; x < bpl; x++)
{
dest[destOffset + x] = (byte) (src[srcOffset + x] + dest[destOffset
+ x - destDy]);
}
}
}
}