File indexing completed on 2024-05-12 15:58:15

 /*
  *  SPDX-FileCopyrightText: 2004 Michael Thaler <michael.thaler@physik.tu-muenchen.de>
  *  SPDX-FileCopyrightText: 2005 C. Boemann <cbo@boemann.dk>
  *  SPDX-FileCopyrightText: 2013 Juan Palacios <jpalaciosdev@gmail.com>
  *
  *  SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #include "kis_filter_strategy.h"
 
 #include <math.h>
 
 #include <klocalizedstring.h>
 #include <QGlobalStatic>
 
 #include "kis_debug.h"
 #include <QtMath>
 #include <QSize>
 
 Q_GLOBAL_STATIC(KisFilterStrategyRegistry, s_instance)
 
 qreal KisHermiteFilterStrategy::valueAt(qreal t, qreal weightsPositionScale) const
 {
     Q_UNUSED(weightsPositionScale);
     /* 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);
 }
 
 qint32 KisHermiteFilterStrategy::intValueAt(qint32 t, qreal weightsPositionScale) const
 {
     Q_UNUSED(weightsPositionScale);
     /* 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 positive 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);
 }
 
 qint32 KisBicubicFilterStrategy::intValueAt(qint32 t, qreal weightsPositionScale) const
 {
     Q_UNUSED(weightsPositionScale);
     /* f(t) = 1.5|t|^3 - 2.5|t|^2 + 1, -1 <= t <= 1 */
     if (t < 0) t = -t;
     if (t < 256) {
         t = (3 * t - 5 * 256) * t * t / 2 + (256 << 16);
 
         //go from .24 fixed point to .8 fixedpoint (hack only works with positive 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;
     }
     if (t < 512) {
         /* f(t) = -0.5|t|^3 + 2.5|t|^2 + 4|t| - 2, -2 <= t <= 2 */
         t = ((-t + 5 * 256) * t / 2 - 4 * 256 * 256) * t + (2 * 256 << 16);
 
         //go from .24 fixed point to .8 fixedpoint (hack only works with positive 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);
 }
 
 qreal KisBoxFilterStrategy::valueAt(qreal t, qreal weightsPositionScale) const
 {
     if ((t >= -0.5  * weightsPositionScale) && (t < 0.5 * weightsPositionScale)) return(1.0);
     return(0.0);
 }
 
 qint32 KisBoxFilterStrategy::intValueAt(qint32 t, qreal weightsPositionScale) const
 {
     /* f(t) = 1, -0.5 < t <= 0.5 */
     if ((t >= -128  * weightsPositionScale) && (t < 128 * weightsPositionScale))
         return 255;
     return 0;
 }
 
 
 qreal KisBoxFilterStrategy::support(qreal weightsPositionScale)
 {
     return supportVal*weightsPositionScale;
 }
 
 qint32 KisBoxFilterStrategy::intSupport(qreal weightsPositionScale)
 {
     return qCeil(intSupportVal*weightsPositionScale);
 }
 
 qreal KisBilinearFilterStrategy::valueAt(qreal t, qreal weightsPositionScale) const
 {
     Q_UNUSED(weightsPositionScale);
     if (t < 0.0) t = -t;
     if (t < 1.0) return(1.0 - t);
     return(0.0);
 }
 
 qint32 KisBilinearFilterStrategy::intValueAt(qint32 t, qreal weightsPositionScale) const
 {
     Q_UNUSED(weightsPositionScale);
     /* 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);
 }
 
 
 qreal KisBellFilterStrategy::valueAt(qreal t, qreal weightsPositionScale) const
 {
     Q_UNUSED(weightsPositionScale);
     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);
 }
 
 qreal KisBSplineFilterStrategy::valueAt(qreal t, qreal weightsPositionScale) const
 {
     Q_UNUSED(weightsPositionScale);
     qreal 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);
 }
 
 qreal KisLanczos3FilterStrategy::valueAt(qreal t, qreal weightsPositionScale) const
 {
     Q_UNUSED(weightsPositionScale);
     if (t < 0) t = -t;
     if (t < 3.0) return(sinc(t) * sinc(t / 3.0));
     return(0.0);
 }
 
 qreal KisLanczos3FilterStrategy::sinc(qreal x) const
 {
     const qreal pi = 3.1415926535897932385;
     x *= pi;
     if (x != 0) return(sin(x) / x);
     return(1.0);
 }
 
 qreal KisMitchellFilterStrategy::valueAt(qreal t, qreal weightsPositionScale) const
 {
     Q_UNUSED(weightsPositionScale);
     const qreal B = 1.0 / 3.0;
     const qreal C = 1.0 / 3.0;
     qreal 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()
 {
 }
 
 KisFilterStrategyRegistry::~KisFilterStrategyRegistry()
 {
     Q_FOREACH (const QString &id, keys()) {
         delete get(id);
     }
     dbgRegistry << "deleting KisFilterStrategyRegistry";
 }
 
 KisFilterStrategyRegistry* KisFilterStrategyRegistry::instance()
 {
     if (!s_instance.exists()) {
         s_instance->add(new KisBoxFilterStrategy);
         s_instance->addAlias("Box", "NearestNeighbor");
 
         s_instance->add(new KisHermiteFilterStrategy);
         s_instance->add(new KisBicubicFilterStrategy);
         s_instance->add(new KisBilinearFilterStrategy);
         s_instance->add(new KisBellFilterStrategy);
         s_instance->add(new KisBSplineFilterStrategy);
         s_instance->add(new KisLanczos3FilterStrategy);
         s_instance->add(new KisMitchellFilterStrategy);
     }
     return s_instance;
 }
 
 QList<KoID> KisFilterStrategyRegistry::listKeys() const
 {
     QList<KoID> answer;
     Q_FOREACH (const QString key, keys()) {
         answer.append(KoID(key, get(key)->name()));
     }
 
     return answer;
 }
 
 QString KisFilterStrategyRegistry::formattedDescriptions() const
 {
     QString formatedDescription("<html><head/><body>");
 
     Q_FOREACH (const QString key, keys()) {
         KisFilterStrategy *strategy = get(key);
         QString description = strategy->description();
 
         if (!description.isEmpty()) {
             formatedDescription.append("<p><span style=\"font-weight:600;\">");
             formatedDescription.append(strategy->name());
             formatedDescription.append("</span>: ");
             formatedDescription.append(description);
             formatedDescription.append("</p>");
         }
     }
     formatedDescription.append("</body></html>");
 
     return formatedDescription;
 }
 
 KisFilterStrategy *KisFilterStrategyRegistry::autoFilterStrategy(QSize originalSize, QSize desiredSize) const
 {
     // Default to nearest neighbor scaling for tiny source images. (i.e: icons or small sprite sheets.)
     const int pixelArtThreshold = 256;
     if (originalSize.width() <= pixelArtThreshold ||
         originalSize.height() <= pixelArtThreshold) {
         return KisFilterStrategyRegistry::instance()->value("NearestNeighbor");
     }
 
     const float xScaleFactor = (float)desiredSize.width() / originalSize.width();
     const float yScaleFactor = (float)desiredSize.height() / originalSize.height();
 
     if (xScaleFactor > 1.f || yScaleFactor > 1.f) { // Enlargement.
         return KisFilterStrategyRegistry::instance()->value("Bicubic");
     } else if (xScaleFactor < 1.f || yScaleFactor < 1.f) { // Reduction.
         return KisFilterStrategyRegistry::instance()->value("Bicubic");
     }
 
     return KisFilterStrategyRegistry::instance()->value("NearestNeighbor");
 }