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 override
virtual double	invTransform (double value) const override
virtual double	bounded (double value) const override
virtual QwtTransform *	copy () const override
Public Member Functions inherited from QwtTransform
	QwtTransform ()
	Constructor.
virtual	~QwtTransform ()
	Destructor.

Static Public Attributes
static const double	LogMin = 1.0e-150
	Smallest allowed value for logarithmic scales: 1.0e-150.
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.

Definition at line 100 of file qwt_transform.h.

Member Function Documentation

bounded()

double QwtLogTransform::bounded ( double  value ) const

overridevirtual

Parameters

value

Value to be bounded

Returns

qBound( LogMin, value, LogMax )

Reimplemented from QwtTransform.

Definition at line 106 of file qwt_transform.cpp.

copy()

QwtTransform * QwtLogTransform::copy ( ) const

overridevirtual

Returns

Clone of the transformation

Implements QwtTransform.

Definition at line 112 of file qwt_transform.cpp.

invTransform()

double QwtLogTransform::invTransform ( double  value ) const

overridevirtual

Parameters

value

Value to be transformed

Returns

exp( value )

Implements QwtTransform.

Definition at line 97 of file qwt_transform.cpp.

transform()

double QwtLogTransform::transform ( double  value ) const

overridevirtual

Parameters

value

Value to be transformed

Returns

log( value )

Implements QwtTransform.

Definition at line 88 of file qwt_transform.cpp.