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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.
 */
 
 #ifndef KGAMMATABLE_H
 #define KGAMMATABLE_H
 
 #include "kookascan_export.h"
 
 #include <qobject.h>
 #include <qvector.h>
 
 /**
  * @short A gamma table.
  *
  * The gamma table maps input intensity values to output values.
  * The transfer function is defined by three parameters gamma, brightness
  * and contrast.  These values are retained internally.
  *
  * When the data from the table is required, either for display or for
  * sending to the scanner, it is calculated and made available as a vector
  * of integers.  Each of these values is in the range 0..(valueRange-1).
  *
  * The @c gamma values specified and returned are expressed as a
  * percentage, so 100 is a linear transfer function.  Reasonable values
  * for the gamma are within the range 30..300 (corresponding to
  * "conventional" gamma values of 0.3..3.0).
  *
  * Reasonable values for the @c brightness and @c contrast are within
  * the range -50..+50.
  *
  * @author Klaas Freitag
  * @author Jonathan Marten
  **/
 
 class KOOKASCAN_EXPORT KGammaTable : public QObject
 {
     Q_OBJECT
 
     Q_PROPERTY(int g READ getGamma WRITE setGamma)
     Q_PROPERTY(int c READ getContrast WRITE setContrast)
     Q_PROPERTY(int b READ getBrightness WRITE setBrightness)
 
 public:
     /**
      * Constructor.
      *
      * Create a new gamma table object, with default parameters or
      * as specified.
      *
      * @param gamma Initial gamma value
      * @param brightness Initial brightness value
      * @param contrast Initial contrast value
      *
      * @note The data array is not allocated at this point.
      **/
     explicit KGammaTable(int gamma = 100, int brightness = 0, int contrast = 0);
 
     /**
      * Copy constructor.
      *
      * @param other Gamma table to be copied
      *
      * @note Only the gamma/brightness/contrast parameters are copied,
      * the data array is neither copied nor allocated.
      **/
     KGammaTable(const KGammaTable &other);
 
     /**
      * Set all of the gamma table parameters in one operation.
      *
      * @param gamma New gamma value
      * @param brightness New brightness value
      * @param contrast New contrast value
      **/
     void setAll(int gamma, int brightness, int contrast);
 
     /**
      * Set the gamma table parameters from a string representation.
      *
      * @param str String value, in the form "gamma,brightness,contrast"
      * where each parameter is a decimal integer.
      *
      * @return @c true if the string format is valid.  If it is not
      * valid, then @c false is returned and the gamma table parameters
      * will not have been changed.
      *
      * @see toString
      **/
     bool setFromString(const QString &str);
 
     /**
      * Convert the gamma table parameters to a string representation.
      *
      * @return The string representation, in the form "gamma,brightness,contrast".
      *
      * @see setFromString
      **/
     QString toString() const;
 
     /**
      * Get the current gamma value.
      *
      * @return The gamma value
      **/
     int getGamma() const
     {
         return (mGamma);
     }
 
     /**
      * Get the current brightness value.
      *
      * @return The brightness value
      **/
     int getBrightness() const
     {
         return (mBrightness);
     }
 
     /**
      * Get the current contrast value.
      *
      * @return The contrast value
      **/
     int getContrast() const
     {
         return (mContrast);
     }
 
     /**
      * Get the currently allocated table size.
      *
      * @return The number of entries in the gamma table.  If the table
      * has not yet been calculated (i.e. @c getTable() has never been
      * called) then the size returned will be zero.  Otherwise, the size
      * returned is the last size requested for @c getTable(), or 256
      * if no explicit size has been requested.
      *
      * @see getTable
      **/
     int tableSize() const
     {
         return (mData.size());
     }
 
     /**
      * Calculate the gamma table values.
      *
      * @param size Size of the table required.  If not specified, then
      * the previous size requested for the table is retained.  If no
      * explicit size has ever been requested, then 256 is assumed.
      *
      * @return A pointer to the array of values
      **/
     const int *getTable(int size = -1);
 
     /**
      * The range of values that will be found in the table.
      **/
     static const int valueRange = 256;
 
 public slots:
     /**
      * Set a new brightness value.
      *
      * @param brightness New brightness value
      **/
     void setBrightness(int brightness);
 
     /**
      * Set a new contrast value.
      *
      * @param contrast New contrast value
      **/
     void setContrast(int contrast);
 
     /**
      * Set a new gamma value.
      *
      * @param gamma New gamma value
      **/
     void setGamma(int gamma);
 
 signals:
     /**
      * Emitted when any of the table parameters (gamma, brightness or
      * contrast) have changed.
      **/
     void tableChanged();
 
 private:
     void init();
     void calcTable();
 
     int mGamma;
     int mBrightness;
     int mContrast;
     bool mDirty;
 
     QVector<int> mData;
 };
 
 #endif                          // KGAMMATABLE_H