qgsscaleexpression.h

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/***************************************************************************
 qgsscaleexpression.h
 ---------------------
 begin                : November 2014
 copyright            : (C) 2014 by Vincent Mora
 email                : vincent dor mora at oslandia dot com
 ***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef QGSSCALEEXPRESSION_H
#define QGSSCALEEXPRESSION_H

#include "qgsexpression.h"

class CORE_EXPORT QgsScaleExpression : public QgsExpression
{
  public:

    enum Type
    {
      Linear,
      Area,
      Flannery,
      Exponential,
      Unknown
    };

    QgsScaleExpression( const QString &expression );

    QgsScaleExpression( Type type, const QString& baseExpression, double minValue, double maxValue, double minSize, double maxSize, double nullSize = 0, double exponent = 1 );

    operator bool() const { return ! mExpression.isEmpty(); }

    double size( double value ) const;

    double minSize() const { return mMinSize; }

    double maxSize() const { return mMaxSize; }

    double minValue() const { return mMinValue; }

    double maxValue() const { return mMaxValue; }

    double nullSize() const { return mNullSize; }

    double exponent() const { return mExponent; }

    QString baseExpression() const { return mExpression; }

    Type type() const { return mType; }

  private:
    QString mExpression;
    Type mType;
    double mMinSize;
    double mMaxSize;
    double mMinValue;
    double mMaxValue;
    double mNullSize;
    double mExponent;

    void init();
    static QString createExpression( Type type, const QString& baseExpr, double minValue, double maxValue, double minSize, double maxSize, double nullSize, double exponent );

};

#endif