NAME

       QwtLogTransform -

       Logarithmic transformation.

SYNOPSIS

       #include <qwt_transform.h>

       Inherits QwtTransform.

   Public Member Functions
       QwtLogTransform ()
           Constructor.
       virtual ~QwtLogTransform ()
           Destructor.
       virtual double transform (double value) const
       virtual double invTransform (double value) const
       virtual double bounded (double value) const
       virtual QwtTransform * copy () const

   Public Attributes
       QT_STATIC_CONST double LogMin = 1.0e-150
           Smallest allowed value for logarithmic scales: 1.0e-150.
       QT_STATIC_CONST double LogMax = 1.0e150
           Largest allowed value for logarithmic scales: 1.0e150.

Detailed Description

       Logarithmic transformation.

       QwtLogTransform modifies the values using log() and exp().

       Note:
           In the calculations of QwtScaleMap the base of the log function has no effect on the
           mapping. So QwtLogTransform can be used for log2(), log10() or any other logarithmic
           scale.

Member Function Documentation

   double QwtLogTransform::bounded (doublevalue) const [virtual]
       Parameters:
           value Value to be bounded

       Returns:
           qBound( LogMin, value, LogMax )

       Reimplemented from QwtTransform.

   QwtTransform * QwtLogTransform::copy () const [virtual]
       Returns:
           Clone of the transformation

       Implements QwtTransform.

   double QwtLogTransform::invTransform (doublevalue) const [virtual]
       Parameters:
           value Value to be transformed

       Returns:
           exp( value )

       Implements QwtTransform.

   double QwtLogTransform::transform (doublevalue) const [virtual]
       Parameters:
           value Value to be transformed

       Returns:
           log( value )

       Implements QwtTransform.

Author

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