QwtLogTransform(3) Qwt User's Guide QwtLogTransform(3)

QwtLogTransform - Logarithmic transformation.

#include <qwt_transform.h>

Inherits QwtTransform.


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


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.

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.

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.

Parameters:

value Value to be transformed

Returns:

exp( value )

Implements QwtTransform.

Parameters:

value Value to be transformed

Returns:

log( value )

Implements QwtTransform.

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Wed Jan 2 2019 Version 6.1.4