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//
// libavg - Media Playback Engine.
// Copyright (C) 2003-2014 Ulrich von Zadow
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// Current versions can be found at www.libavg.de
//
#include "FilterFastDownscale.h"
#include "Pixeldefs.h"
#include "../base/Exception.h"
#include <iostream>
namespace avg {
using namespace std;
FilterFastDownscale::FilterFastDownscale(int factor)
: Filter(),
m_Factor(factor)
{
}
FilterFastDownscale::~FilterFastDownscale()
{
}
BitmapPtr FilterFastDownscale::apply(BitmapPtr pBmpSrc)
{
AVG_ASSERT(pBmpSrc->getPixelFormat() == I8);
BitmapPtr pBmpDest = BitmapPtr(new Bitmap(pBmpSrc->getSize()/m_Factor, I8,
pBmpSrc->getName()));
unsigned char * pSrcLine = pBmpSrc->getPixels();
unsigned char * pDestLine = pBmpDest->getPixels();
IntPoint size = pBmpDest->getSize();
int srcStride = pBmpSrc->getStride();
for (int y = 0; y < size.y; ++y) {
unsigned char * pSrcPixel = pSrcLine;
unsigned char * pDstPixel = pDestLine;
switch (m_Factor) {
case 2:
for (int x = 0; x < size.x; ++x) {
int dstPixel= int(*pSrcPixel)+int(*(pSrcPixel+1))
+int(*(pSrcPixel+srcStride))+int(*(pSrcPixel+srcStride+1));
*pDstPixel = (dstPixel+2)/4;
pSrcPixel += 2;
pDstPixel++;
}
break;
case 3:
for (int x = 0; x < size.x; ++x) {
int dstPixel= int(*pSrcPixel)+int(*(pSrcPixel+1))+int(*(pSrcPixel+2))
+int(*(pSrcPixel+srcStride))+int(*(pSrcPixel+srcStride+1))
+int(*(pSrcPixel+srcStride+2))
+int(*(pSrcPixel+srcStride*2))+int(*(pSrcPixel+srcStride*2+1))
+int(*(pSrcPixel+srcStride*2+2));
*pDstPixel = (dstPixel+4)/9;
pSrcPixel += 3;
pDstPixel++;
}
break;
default:
for (int x = 0; x < size.x; ++x) {
int dstPixel=0;
for (int y1 = 0; y1 < m_Factor; y1++) {
for (int x1 = 0; x1 < m_Factor; x1++) {
dstPixel+= (int)(*(pSrcPixel+srcStride*y1+x1));
}
}
*pDstPixel = (dstPixel+(m_Factor*m_Factor)/2)/(m_Factor*m_Factor);
pSrcPixel += m_Factor;
pDstPixel++;
}
break;
}
pSrcLine = pSrcLine + pBmpSrc->getStride()*m_Factor;
pDestLine = pDestLine + pBmpDest->getStride();
}
return pBmpDest;
}
} // namespace
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