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filterstamp.cpp

/**********************************************************************************
* Copyright (c) 2003, Matthias Bader and Christoph Rueegg <opendev@cdrnet.ch>     *
* 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         *
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF          *
* THE POSSIBILITY OF SUCH DAMAGE.                                                 *
**********************************************************************************/

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

StampFilter::StampFilter() : ChannelFilter<unsigned char>()
{
  stamp = GrayImage::CreateFromTiff("stamp.tif");
  stamp->LoadAlphaMap("stampa.tif");
}

StampFilter::~StampFilter()
{
  delete stamp;
}

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

void StampFilter::OnMouseEvent(const int button, const int state, int x, int y)
{
  if(state == 0 && button == 0)
  {
    
  int i, j;
  int i_left, i_right, j_top, j_bottom;
  float alpha;

  //assert(StampImage->width==StampImageAlpha->width);         //do the two stamp images have the same dimensions?
  //assert(StampImage->height==StampImageAlpha->height);

  i_left=0;
  j_top=0;
  i_right=stamp->GetWidth();
  j_bottom=stamp->GetHeight();
  x -= i_right/2;
  y -= j_bottom/2;

  if (x+i_right>GetWidth())   i_right=GetWidth()-x; //we don't want to stamp off-image areas
  if (y+j_bottom>GetHeight())  j_bottom=GetHeight()-y;
  if (x<0)                              i_left=-x;
  if (y<0)                               j_top=-y;

  for (j=j_top; j<j_bottom; j++)
  {
    for (i=i_left; i<i_right; i++)
    {
      alpha=(stamp->GetAlpha(i,j))/255.0f;    //this is the alpha value. It goes from [0 to 1]. 0 means transparent, 1 means solid.
      Set(i+x,j+y,(unsigned char)(alpha*stamp->GetLuminance(i,j)+(1-alpha)*Get(i+x,j+y)));
      //img->data[(i + destleft) + (j + desttop)*img->width] = (unsigned char) (alpha*StampImage->data[i + j*StampImage->width] + (1-alpha)*img->data[(i + destleft) + (j + desttop)*img->width]);
    }                                        //the line above renders the stampImage into img by using the alpha values from stampImageAlpha
  }
  }
}

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