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tdegraphics/libkscan/kgammatable.cpp

94 lines
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/* This file is part of the KDE Project
Copyright (C) 2002 Klaas Freitag <freitag@suse.de>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include <math.h>
#include <kdebug.h>
#include "kgammatable.h"
KGammaTable::KGammaTable( int gamma, int brightness, int contrast )
: TQObject()
{
g = gamma < 1 ? 1 : gamma;
b = brightness;
c = contrast;
gt.resize(256);
calcTable();
}
const KGammaTable& KGammaTable::operator=(const KGammaTable& gt)
{
if( this != &gt )
{
g = gt.g;
b = gt.b;
c = gt.c;
calcTable();
}
return( *this );
}
inline SANE_Word adjust( SANE_Word x, int gl,int bl,int cl)
{
//printf("x : %d, x/256 : %lg, g : %d, 100/g : %lg",
// x,(double)x/256.0,g,100.0/(double)g);
x = ( SANE_Int )(256*pow((double)x/256.0,100.0/(double)gl));
x = ((65536/(128-cl)-256)*(x-128)>>8)+128+bl;
if(x<0) x = 0; else if(x>255) x = 255;
//printf(" -> %d\n",x);
return x;
}
void KGammaTable::calcTable( )
{
int br = (b<<8)/(128-c);
int gr = g;
int cr = c;
if( gr == 0 )
{
kdDebug(29000) << "Cant calc table -> would raise div. by zero !" << endl;
return;
}
for( SANE_Word i = 0; i<256; i++)
gt[i] = adjust(i, gr, br, cr );
dirty = false;
}
void KGammaTable::setAll( int gamma, int brightness, int contrast )
{
g = gamma < 1 ? 1 : gamma;
b = brightness;
c = contrast;
dirty = true;
}
SANE_Word* KGammaTable::getTable()
{
if( dirty ) calcTable();
return( gt.data());
}
#include "kgammatable.moc"