#include <qwt_double_range.h>

Inheritance diagram for QwtDoubleRange:

Public Member Functions
	QwtDoubleRange ()
virtual	~QwtDoubleRange ()
virtual void	fitValue (double)
virtual void	incPages (int)
virtual void	incValue (int)
bool	isValid () const
double	maxValue () const
double	minValue () const
int	pageSize () const
bool	periodic () const
void	setPeriodic (bool tf)
void	setRange (double vmin, double vmax, double vstep=0.0, int pagesize=1)
void	setStep (double)
void	setValid (bool)
virtual void	setValue (double)
double	step () const
double	value () const

Protected Member Functions
double	exactPrevValue () const
double	exactValue () const
double	prevValue () const
virtual void	rangeChange ()
virtual void	stepChange ()
virtual void	valueChange ()

Detailed Description

A class which controls a value within an interval.

This class is useful as a base class or a member for sliders. It represents an interval of type double within which a value can be moved. The value can be either an arbitrary point inside the interval (see QwtDoubleRange::setValue), or it can be fitted into a step raster (see QwtDoubleRange::fitValue and QwtDoubleRange::incValue).

As a special case, a QwtDoubleRange can be periodic, which means that a value outside the interval will be mapped to a value inside the interval when QwtDoubleRange::setValue(), QwtDoubleRange::fitValue(), QwtDoubleRange::incValue() or QwtDoubleRange::incPages() are called.

Constructor & Destructor Documentation

QwtDoubleRange::QwtDoubleRange ( )

The range is initialized to [0.0, 100.0], the step size to 1.0, and the value to 0.0.

Member Function Documentation

double QwtDoubleRange::exactValue ( ) const

protected

Returns the exact value.

The exact value is the value which QwtDoubleRange::value would return if the value were not adjusted to the step raster. It differs from the current value only if QwtDoubleRange::fitValue or QwtDoubleRange::incValue have been used before. This function is intended for internal use in derived classes.

void QwtDoubleRange::fitValue ( double x )

virtual

Adjust the value to the closest point in the step raster.

Parameters:

x value

Warning:

The value is clipped when it lies outside the range. When the range is QwtDoubleRange::periodic, it will be mapped to a point in the interval such that

new value := x + n * (max. value - min. value)

with an integer number n.

Reimplemented in QwtAbstractSlider.

void QwtDoubleRange::incPages ( int nPages )

virtual

Increment the value by a specified number of pages.

Parameters:

nPages Number of pages to increment. A negative number decrements the value.

Warning:: The Page size is specified in the constructor.

void QwtDoubleRange::incValue ( int nSteps )

virtual

Increment the value by a specified number of steps.

Parameters:

nSteps Number of steps to increment

Warning:: As a result of this operation, the new value will always be adjusted to the step raster.

Reimplemented in QwtAbstractSlider.

double QwtDoubleRange::maxValue ( ) const

Returns the value of the second border of the range.

maxValue returns the value which has been specified as the second parameter in QwtDoubleRange::setRange.

See also:: setRange()

double QwtDoubleRange::minValue ( ) const

Returns the value at the first border of the range.

minValue returns the value which has been specified as the first parameter in setRange().

See also:: setRange()

bool QwtDoubleRange::periodic ( ) const

Returns true if the range is periodic.

See also:: setPeriodic()

void QwtDoubleRange::rangeChange ( )

protectedvirtual

Notify a change of the range.

This virtual function is called whenever the range changes. The default implementation does nothing.

Reimplemented in QwtDial, QwtCounter, and QwtSlider.

void QwtDoubleRange::setPeriodic ( bool tf )

Make the range periodic.

When the range is periodic, the value will be set to a point inside the interval such that

point = value + n * width

if the user tries to set a new value which is outside the range. If the range is nonperiodic (the default), values outside the range will be clipped.

Parameters:

tf	true for a periodic range

void QwtDoubleRange::setRange	(	double	vmin,
		double	vmax,
		double	vstep = `0.0`,
		int	pageSize = `1`
	)

Specify range and step size.

Parameters:

vmin	lower boundary of the interval
vmax	higher boundary of the interval
vstep	step width
pageSize	page size in steps

Warning:

A change of the range changes the value if it lies outside the new range. The current value will not be adjusted to the new step raster.
vmax < vmin is allowed.
If the step size is left out or set to zero, it will be set to 1/100 of the interval length.
If the step size has an absurd value, it will be corrected to a better one.

void QwtDoubleRange::setStep ( double vstep )

Change the step raster.

Parameters:

vstep new step width

Warning:: The value will not be adjusted to the new step raster.

Reimplemented in QwtCounter.

void QwtDoubleRange::setValue ( double x )

virtual

Set a new value without adjusting to the step raster.

Parameters:

x new value

Warning:

The value is clipped when it lies outside the range. When the range is QwtDoubleRange::periodic, it will be mapped to a point in the interval such that

new value := x + n * (max. value - min. value)

with an integer number n.

Reimplemented in QwtCounter, and QwtAbstractSlider.

double QwtDoubleRange::step ( ) const

Returns:: the step size

See also:: setStep(), setRange()

Reimplemented in QwtCounter.

void QwtDoubleRange::stepChange ( )

protectedvirtual

Notify a change of the step size.

This virtual function is called whenever the step size changes. The default implementation does nothing.

void QwtDoubleRange::valueChange ( )

protectedvirtual

Notify a change of value.

This virtual function is called whenever the value changes. The default implementation does nothing.

Reimplemented in QwtDial, QwtAbstractSlider, QwtSlider, and QwtWheel.

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation