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/*
* Copyright (c) 2004 Michael Thaler <michael.thaler@physik.tu-muenchen.de>
* Copyright (c) 2005 Casper Boemann <cbr@boemann.dk>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <kdebug.h>
#include <tdelocale.h>
#include "kis_debug_areas.h"
#include "kis_filter_strategy.h"
#include <math.h>
double KisHermiteFilterStrategy::valueAt(double t) const {
/* f(t) = 2|t|^3 - 3|t|^2 + 1, -1 <= t <= 1 */
if(t < 0.0) t = -t;
if(t < 1.0) return((2.0 * t - 3.0) * t * t + 1.0);
return(0.0);
}
TQ_UINT32 KisHermiteFilterStrategy::intValueAt(TQ_INT32 t) const {
/* f(t) = 2|t|^3 - 3|t|^2 + 1, -1 <= t <= 1 */
if(t < 0) t = -t;
if(t < 256)
{
t =(2 * t - 3*256) * t * t +(256<<16);
//go from .24 fixed point to .8 fixedpoint (hack only works with positve numbers, which it is)
t = (t + 0x8000) >> 16;
// go from .8 fixed point to 8bitscale. ie t = (t*255)/256;
if(t >= 128)
return t - 1;
return t;
}
return(0);
}
double KisCubicFilterStrategy::valueAt(double x) const {
if (x < -2.0)
return(0.0);
if (x < -1.0)
return((2.0+x)*(2.0+x)*(2.0+x)/6.0);
if (x < 0.0)
return((4.0+x*x*(-6.0-3.0*x))/6.0);
if (x < 1.0)
return((4.0+x*x*(-6.0+3.0*x))/6.0);
if (x < 2.0)
return((2.0-x)*(2.0-x)*(2.0-x)/6.0);
return(0.0);
}
TQ_UINT32 KisCubicFilterStrategy::intValueAt(TQ_INT32 x) const {
if (x < 2)
return 0;
if (x < -1)
return (2 + x) * (2 + x) * ( 2 + x) / 6;
if ( x < 0)
return (4 + x * x * ( -6 - 3 * x)) / 6;
if (x < 1)
return (4 + x * x * ( -6 + 3 * x)) / 6;
if (x < 2)
return (2 - x) * ( 2 - x) * (2 - x) / 6;
return 0;
}
double KisBoxFilterStrategy::valueAt(double t) const {
if((t > -0.5) && (t <= 0.5)) return(1.0);
return(0.0);
}
TQ_UINT32 KisBoxFilterStrategy::intValueAt(TQ_INT32 t) const {
/* f(t) = 1, -0.5 < t <= 0.5 */
if((t > -128) && (t <= 128))
return 255;
return 0;
}
double KisTriangleFilterStrategy::valueAt(double t) const {
if(t < 0.0) t = -t;
if(t < 1.0) return(1.0 - t);
return(0.0);
}
TQ_UINT32 KisTriangleFilterStrategy::intValueAt(TQ_INT32 t) const {
/* f(t) = |t|, -1 <= t <= 1 */
if(t < 0) t = -t;
if(t < 256)
{
// calc 256-1 but also go from .8 fixed point to 8bitscale. ie t = (t*255)/256; ie: if(t>=128) return t-1;
if(t>=128) return 256 - t;
return 255 - t;
}
return(0);
}
double KisBellFilterStrategy::valueAt(double t) const {
if(t < 0) t = -t;
if(t < .5) return(.75 - (t * t));
if(t < 1.5) {
t = (t - 1.5);
return(.5 * (t * t));
}
return(0.0);
}
double KisBSplineFilterStrategy::valueAt(double t) const {
double tt;
if(t < 0) t = -t;
if(t < 1) {
tt = t * t;
return((.5 * tt * t) - tt + (2.0 / 3.0));
} else if(t < 2) {
t = 2 - t;
return((1.0 / 6.0) * (t * t * t));
}
return(0.0);
}
double KisLanczos3FilterStrategy::valueAt(double t) const {
if(t < 0) t = -t;
if(t < 3.0) return(sinc(t) * sinc(t/3.0));
return(0.0);
}
double KisLanczos3FilterStrategy::sinc(double x) const {
const double pi=3.1415926535897932385;
x *= pi;
if(x != 0) return(sin(x) / x);
return(1.0);
}
double KisMitchellFilterStrategy::valueAt(double t) const {
const double B=1.0/3.0;
const double C=1.0/3.0;
double tt;
tt = t * t;
if(t < 0) t = -t;
if(t < 1.0) {
t = (((12.0 - 9.0 * B - 6.0 * C) * (t * tt)) + ((-18.0 + 12.0 * B + 6.0 * C) * tt) + (6.0 - 2 * B));
return(t / 6.0);
} else if(t < 2.0) {
t = (((-1.0 * B - 6.0 * C) * (t * tt)) + ((6.0 * B + 30.0 * C) * tt) + ((-12.0 * B - 48.0 * C) * t) + (8.0 * B + 24 * C));
return(t / 6.0);
}
return(0.0);
}
KisFilterStrategyRegistry *KisFilterStrategyRegistry::m_singleton = 0;
KisFilterStrategyRegistry::KisFilterStrategyRegistry()
{
Q_ASSERT(KisFilterStrategyRegistry::m_singleton == 0);
KisFilterStrategyRegistry::m_singleton = this;
}
KisFilterStrategyRegistry::~KisFilterStrategyRegistry()
{
}
KisFilterStrategyRegistry* KisFilterStrategyRegistry::instance()
{
if(KisFilterStrategyRegistry::m_singleton == 0)
{
KisFilterStrategyRegistry::m_singleton = new KisFilterStrategyRegistry();
TQ_CHECK_PTR(KisFilterStrategyRegistry::m_singleton);
m_singleton->add(new KisHermiteFilterStrategy);
m_singleton->add(new KisBoxFilterStrategy);
m_singleton->add(new KisTriangleFilterStrategy);
m_singleton->add(new KisBellFilterStrategy);
m_singleton->add(new KisBSplineFilterStrategy);
// m_singleton->add(new KisLanczos3FilterStrategy);
m_singleton->add(new KisMitchellFilterStrategy);
// m_singleton->add(new KisCubicFilterStrategy);
}
return KisFilterStrategyRegistry::m_singleton;
}
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