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 QwtTransform *	copy () const
Public Member Functions inherited from QwtTransform
	QwtTransform ()
	Constructor.
virtual	~QwtTransform ()
	Destructor.

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

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 ( double  value ) const

virtual

Parameters

value

Value to be transformed

Returns

exp( value )

Implements QwtTransform.

double QwtLogTransform::transform ( double  value ) const

virtual

Parameters

value

Value to be transformed

Returns

log( value )

Implements QwtTransform.