Qwt User's Guide
QwtLogTransform Class Reference

Logarithmic transformation. More...

#include <qwt_transform.h>

Inheritance diagram for QwtLogTransform:

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 QwtTransformcopy () 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 ( double  value) const [virtual]
Parameters:
valueValue 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 ( double  value) const [virtual]
Parameters:
valueValue to be transformed
Returns:
exp( value )

Implements QwtTransform.

double QwtLogTransform::transform ( double  value) const [virtual]
Parameters:
valueValue to be transformed
Returns:
log( value )

Implements QwtTransform.

List of all members.

 All Classes Functions Variables Typedefs Enumerations Enumerator