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filterpr.cpp

/**********************************************************************************
* Copyright (c) 2003, Christoph Rueegg <opendev@cdrnet.ch> and Matthias Bader     *
* All rights reserved.                                                            *
*                                                                                 *
* Project Website: http://www.cdrnet.net/projects/painter/                        *
*                                                                                 *
* 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.                          *
*                                                                                 *
* 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 COPYRIGHT OWNER 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 ANY THEORY OF LIABILITY, WHETHER IN         *
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)         *
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF          *
* THE POSSIBILITY OF SUCH DAMAGE.                                                 *
**********************************************************************************/

#include "filterpr.h"
#include <cmath>

PrFilter::PrFilter() : StatefullTransformationFilter()
{
}

PrFilter::~PrFilter()
{
}

ChannelFilter<unsigned char>* PrFilter::EmptyClone()
{
  PrFilter *copy = new PrFilter();
  copy->SetSubChannel(GetSubChannel());
  return(copy);
}

void PrFilter::OnStart(Channel<unsigned char>* source, Channel<unsigned char>* target, int x, int y)
{
  height = target->GetHeight();
  width = target->GetWidth();
}

void PrFilter::OnEnd(Channel<unsigned char>* source, Channel<unsigned char>* target, int x0, int y0, int x1, int y1)
{
  int height = target->GetHeight();
  int width = target->GetWidth();
  for(int x=0;x<width;x++)
    for(int y=0;y<height;y++)
      source->Set(x,y,target->Get(x,y));
}

bool PrFilter::OnRender(Channel<unsigned char>* source, Channel<unsigned char>* target, int x0, int y0, int x1, int y1)
{
  int current, sum;
  for(int x=0;x<width;x++)
    for(int y=0;y<height;y++)
    {
      current = target->Get(x,y);
      sum = 0;
      if(x>0)
        sum+=source->Get(x-1,y);
      if(y>0)
        sum+=source->Get(x,y-1);
      if(x<width-1)
        sum+=source->Get(x+1,y);
      if(y<height-1)
        sum+=source->Get(x,y+1);
      sum /= 16;
      if(abs(sum) > 16)
        target->Set(x,y,(unsigned)(abs(current+(sum))%255));
    }
  return(true);
}

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