File indexing completed on 2025-01-19 12:59:18

 /* 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 "kgammatable.h"
 
 #include <math.h>
 
 #include <qregexp.h>
 
 #include "libkookascan_logging.h"
 
 
 KGammaTable::KGammaTable(int gamma, int brightness, int contrast)
     : QObject()
 {
     mGamma = (gamma < 1) ? 1 : gamma;
     mBrightness = brightness;
     mContrast = contrast;
     init();
 }
 
 KGammaTable::KGammaTable(const KGammaTable &other)
     : QObject()
 {
     mGamma = other.mGamma;
     mBrightness = other.mBrightness;
     mContrast = other.mContrast;
     init();
 }
 
 void KGammaTable::init()
 {
     mDirty = true;
 }
 
 // Adapted from LabeledGamma::calculateGT()
 // in kdegraphics/libksane/libksane/widgets/labeled_gamma.cpp
 //
 // Input values are expected to be:
 //   brightness     -50 ... +50
 //   contrast       -50 ... +50
 //   gamma           30 ... 300 = 0.3 ... 3.0
 //
 void KGammaTable::calcTable()
 {
     if (mGamma < 1.0) {             // impossibly small
         qCWarning(LIBKOOKASCAN_LOG) << "invalid gamma" << mGamma;
         mDirty = false;                 // pointless, but don't repeat
         return;
     }
 
     if (mData.isEmpty()) {              // not allocated yet
         mData.resize(256);              // do it now
         qCDebug(LIBKOOKASCAN_LOG) << "allocated table size" << mData.size();
     }
 
     qCDebug(LIBKOOKASCAN_LOG) << "initial b" << mBrightness << "c" << mContrast << "g" << mGamma;
 
     const double maxval = (KGammaTable::valueRange - 1);
     double gam = 100.0 / mGamma;
     double con = (200.0 / (100.0 - mContrast)) - 1;
     double halfmax = maxval / 2.0;
     double bri = (mBrightness / halfmax) * maxval;
     qCDebug(LIBKOOKASCAN_LOG) << "adjusted bri" << bri << "con" << con << "gam" << gam;
 
     for (int i = 0; i < mData.size(); ++i) {
         double x = pow(i / maxval, gam) * maxval;   // apply gamma
         x = (con * (x - halfmax)) + halfmax;    // apply contrast
         x += bri;                   // apply brightness
         mData[i] = qRound(qBound(0.0, x, maxval));  // limit value, save in table
         //qCDebug(LIBKOOKASCAN_LOG) << "  " << i << "->" << mData[i];
     }
 
     mDirty = false;                 // table now calculated
 }
 
 void KGammaTable::setBrightness(int brightness)     // slot
 {
     mBrightness = brightness;
     mDirty = true;
     emit tableChanged();
 }
 
 void KGammaTable::setContrast(int contrast)     // slot
 {
     mContrast = contrast;
     mDirty = true;
     emit tableChanged();
 }
 
 void KGammaTable::setGamma(int gamma)           // slot
 {
     mGamma = gamma;
     mDirty = true;
     emit tableChanged();
 }
 
 void KGammaTable::setAll(int gamma, int brightness, int contrast)
 {
     mGamma = gamma < 1 ? 1 : gamma;
     mBrightness = brightness;
     mContrast = contrast;
 
     mDirty = true;
     emit tableChanged();
 }
 
 const int *KGammaTable::getTable(int size)
 {
     if (size > 0 && size != mData.size()) {
         qCDebug(LIBKOOKASCAN_LOG) << "resize from" << mData.size() << "to" << size;
         mData.resize(size);
         mDirty = true;
     }
 
     if (mDirty) {
         calcTable();
     }
     return (mData.constData());
 }
 
 // originally done in KScanOption::set(const QByteArray &)
 bool KGammaTable::setFromString(const QString &str)
 {
     QRegExp re("(\\d+),(\\d+),(\\d+)");
     if (!re.exactMatch(str)) {
         return (false);    // unrecognised format
     }
 
     int g = re.cap(1).toInt();
     int b = re.cap(2).toInt();
     int c = re.cap(3).toInt();
 
     setAll(g, b, c);
     return (true);                  // matched and set
 }
 
 // originally done in KScanOption::get()
 QString KGammaTable::toString() const
 {
     return (QString("%1,%2,%3").arg(mGamma).arg(mBrightness).arg(mContrast));
 }