SYNOPSIS

#include <qwt_scale_engine.h>

Inherits QwtScaleEngine.

Public Member Functions

QwtLogScaleEngine (uint base=10)

virtual ~QwtLogScaleEngine ()
Destructor.
virtual void autoScale (int maxSteps, double &x1, double &x2, double &stepSize) const

virtual QwtScaleDiv divideScale (double x1, double x2, int numMajorSteps, int numMinorSteps, double stepSize=0.0) const
Calculate a scale division for an interval.

Protected Member Functions

QwtInterval align (const QwtInterval &, double stepSize) const
Align an interval to a step size.
void buildTicks (const QwtInterval &, double stepSize, int maxMinSteps, QList< double > ticks[QwtScaleDiv::NTickTypes]) const
Calculate ticks for an interval.
QList< double > buildMajorTicks (const QwtInterval &interval, double stepSize) const
Calculate major ticks for an interval.
void buildMinorTicks (const QList< double > &majorTicks, int maxMinorSteps, double stepSize, QList< double > &minorTicks, QList< double > &mediumTicks) const
Calculate minor/medium ticks for major ticks.

Additional Inherited Members

Detailed Description

A scale engine for logarithmic scales.

The step size is measured in decades and the major step size will be adjusted to fit the pattern $

---

re n is a natural number including zero.

Warning:

the step size as well as the margins are measured in decades.

Constructor & Destructor Documentation

QwtLogScaleEngine::QwtLogScaleEngine (uintbase = 10)

Constructor

Parameters:

base Base of the scale engine

See Also:

setBase()

Member Function Documentation

QwtInterval QwtLogScaleEngine::align (const QwtInterval &interval, doublestepSize) const [protected]

Align an interval to a step size. The limits of an interval are aligned that both are integer multiples of the step size.

Parameters:

interval Interval
stepSize Step size

Returns:

Aligned interval

void QwtLogScaleEngine::autoScale (intmaxNumSteps, double &x1, double &x2, double &stepSize) const [virtual]

Align and divide an interval

Parameters:

maxNumSteps Max. number of steps
x1 First limit of the interval (In/Out)
x2 Second limit of the interval (In/Out)
stepSize Step size (Out)

See Also:

QwtScaleEngine::setAttribute()

Implements QwtScaleEngine.

QList< double > QwtLogScaleEngine::buildMajorTicks (const QwtInterval &interval, doublestepSize) const [protected]

Calculate major ticks for an interval.

Parameters:

interval Interval
stepSize Step size

Returns:

Calculated ticks

void QwtLogScaleEngine::buildMinorTicks (const QList< double > &majorTicks, intmaxMinorSteps, doublestepSize, QList< double > &minorTicks, QList< double > &mediumTicks) const [protected]

Calculate minor/medium ticks for major ticks.

Parameters:

majorTicks Major ticks
maxMinorSteps Maximum number of minor steps
stepSize Step size
minorTicks Array to be filled with the calculated minor ticks
mediumTicks Array to be filled with the calculated medium ticks

void QwtLogScaleEngine::buildTicks (const QwtInterval &interval, doublestepSize, intmaxMinorSteps, QList< double >ticks[QwtScaleDiv::NTickTypes]) const [protected]

Calculate ticks for an interval.

Parameters:

interval Interval
maxMinorSteps Maximum number of minor steps
stepSize Step size
ticks Arrays to be filled with the calculated ticks

See Also:

buildMajorTicks(), buildMinorTicks

QwtScaleDiv QwtLogScaleEngine::divideScale (doublex1, doublex2, intmaxMajorSteps, intmaxMinorSteps, doublestepSize = 0.0) const [virtual]

Calculate a scale division for an interval.

Parameters:

x1 First interval limit
x2 Second interval limit
maxMajorSteps Maximum for the number of major steps
maxMinorSteps Maximum number of minor steps
stepSize Step size. If stepSize == 0, the engine calculates one.

Returns:

Calculated scale division

Implements QwtScaleEngine.

Author

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