A class which controls a value within an interval. More...

#include <qwt_double_range.h>

Inheritance diagram for QwtDoubleRange:

Public Member Functions
	QwtDoubleRange ()
virtual	~QwtDoubleRange ()
	Destroys the QwtDoubleRange.
void	setRange (double vmin, double vmax, double vstep=0.0, int pagesize=1)
	Specify range and step size.
void	setValid (bool)
	Set the value to be valid/invalid.
bool	isValid () const
	Indicates if the value is valid.
virtual void	setValue (double)
	Set a new value without adjusting to the step raster.
double	value () const
	Returns the current value.
void	setPeriodic (bool tf)
	Make the range periodic.
bool	periodic () const
	Returns true if the range is periodic.
void	setStep (double)
	Change the step raster.
double	step () const
double	maxValue () const
	Returns the value of the second border of the range.
double	minValue () const
	Returns the value at the first border of the range.
int	pageSize () const
	Returns the page size in steps.
virtual void	incValue (int)
	Increment the value by a specified number of steps.
virtual void	incPages (int)
	Increment the value by a specified number of pages.
virtual void	fitValue (double)
	Adjust the value to the closest point in the step raster.
Protected Member Functions
double	exactValue () const
	Returns the exact value.
double	exactPrevValue () const
	Returns the exact previous value.
double	prevValue () const
	Returns the previous value.
virtual void	valueChange ()
	Notify a change of value.
virtual void	stepChange ()
	Notify a change of the step size.
virtual void	rangeChange ()
	Notify a change of the range.

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.

Definition at line 31 of file qwt_double_range.h.

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.

Definition at line 22 of file qwt_double_range.cpp.

                              :
    d_minValue(0.0),
    d_maxValue(0.0),
    d_step(1.0),
    d_pageSize(1),
    d_isValid(false),
    d_value(0.0),
    d_exactValue(0.0),
    d_exactPrevValue(0.0),
    d_prevValue(0.0),
    d_periodic(false)
{
}

QwtDoubleRange::~QwtDoubleRange ( ) [virtual]

Destroys the QwtDoubleRange.

Definition at line 37 of file qwt_double_range.cpp.

{
}

Member Function Documentation

double QwtDoubleRange::exactPrevValue ( ) const [protected]

Returns the exact previous value.

Definition at line 383 of file qwt_double_range.cpp.

Referenced by QwtAbstractSlider::mouseMoveEvent().

{ 
    return d_exactPrevValue; 
}

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.

Definition at line 377 of file qwt_double_range.cpp.

Referenced by QwtAbstractSlider::mouseMoveEvent(), and QwtAbstractSlider::timerEvent().

{ 
    return d_exactValue; 
}

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.

Definition at line 135 of file qwt_double_range.cpp.

{
    setNewValue(x, true);
}

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.

Definition at line 274 of file qwt_double_range.cpp.

References isValid().

Referenced by QwtAbstractSlider::mouseReleaseEvent(), QwtAbstractSlider::timerEvent(), and QwtAbstractSlider::wheelEvent().

{
    if ( isValid() )
        setNewValue(d_value + double(nPages) * double(d_pageSize) * d_step, true);
}

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.

Definition at line 262 of file qwt_double_range.cpp.

References isValid().

Referenced by QwtCounter::keyPressEvent(), and QwtCounter::wheelEvent().

{
    if ( isValid() )
        setNewValue(d_value + double(nSteps) * d_step, true);
}

bool QwtDoubleRange::isValid ( ) const

Indicates if the value is valid.

Reimplemented in QwtAbstractSlider.

Definition at line 52 of file qwt_double_range.cpp.

Referenced by incPages(), incValue(), setValid(), and QwtAbstractSlider::setValid().

{
    return d_isValid;
}

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()

Definition at line 329 of file qwt_double_range.cpp.

Referenced by QwtDial::drawContents(), QwtWheel::drawWheel(), QwtWheel::getValue(), QwtDial::getValue(), QwtDial::keyPressEvent(), QwtCounter::keyPressEvent(), QwtCounter::maxVal(), QwtSlider::rangeChange(), QwtCounter::setMinValue(), QwtCounter::sizeHint(), and QwtDial::updateScale().

{   
    return d_maxValue;
}

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()

Definition at line 342 of file qwt_double_range.cpp.

Referenced by QwtDial::drawContents(), QwtWheel::drawWheel(), QwtWheel::getValue(), QwtDial::getValue(), QwtDial::keyPressEvent(), QwtCounter::keyPressEvent(), QwtCounter::minVal(), QwtSlider::rangeChange(), QwtCounter::setMaxValue(), QwtCounter::sizeHint(), and QwtDial::updateScale().

{
    return d_minValue; 
}

int QwtDoubleRange::pageSize ( ) const

Returns the page size in steps.

Definition at line 357 of file qwt_double_range.cpp.

Referenced by QwtDial::keyPressEvent().

{ 
    return d_pageSize; 
}

bool QwtDoubleRange::periodic ( ) const

Returns true if the range is periodic.

See also:: setPeriodic()

Definition at line 351 of file qwt_double_range.cpp.

{ 
    return d_periodic; 
}

double QwtDoubleRange::prevValue ( ) const [protected]

Returns the previous value.

Definition at line 389 of file qwt_double_range.cpp.

Referenced by QwtDial::keyPressEvent(), QwtAbstractSlider::keyPressEvent(), QwtAbstractSlider::mouseMoveEvent(), and QwtAbstractSlider::wheelEvent().

{ 
    return d_prevValue; 
}

void QwtDoubleRange::rangeChange ( ) [protected, virtual]

Notify a change of the range.

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

Reimplemented in QwtCounter, QwtDial, and QwtSlider.

Definition at line 297 of file qwt_double_range.cpp.

Referenced by setRange().

{
}

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

Definition at line 251 of file qwt_double_range.cpp.

Referenced by QwtDial::setWrapping().

{
    d_periodic = tf;
}

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.

Definition at line 172 of file qwt_double_range.cpp.

References qwtAbs, qwtLim(), rangeChange(), and setStep().

Referenced by QwtCounter::setMaxValue(), and QwtCounter::setMinValue().

{
    bool rchg = ((d_maxValue != vmax) || (d_minValue != vmin));
    
    if (rchg) 
    {
        d_minValue = vmin;
        d_maxValue = vmax;
    }
    
    //
    // look if the step width has an acceptable 
    // value or otherwise change it.
    //
    setStep(vstep);

    //
    // limit page size
    //
    d_pageSize = qwtLim(pageSize,0, 
        int(qwtAbs((d_maxValue - d_minValue) / d_step))); 
    
    // 
    // If the value lies out of the range, it 
    // will be changed. Note that it will not be adjusted to 
    // the new step width.
    setNewValue(d_value, false);
    
    // call notifier after the step width has been 
    // adjusted.
    if (rchg)
       rangeChange();
}

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.

Definition at line 211 of file qwt_double_range.cpp.

References DefaultRelStep, MinRelStep, and stepChange().

Referenced by setRange().

{
    double intv = d_maxValue - d_minValue;
    
    double newStep;
    if (vstep == 0.0)
       newStep = intv * DefaultRelStep;
    else
    {
        if ((intv > 0) && (vstep < 0) || (intv < 0) && (vstep > 0))
           newStep = -vstep;
        else
           newStep = vstep;
        
        if ( fabs(newStep) < fabs(MinRelStep * intv) )
           newStep = MinRelStep * intv;
    }
    
    if (newStep != d_step)
    {
        d_step = newStep;
        stepChange();
    }
}

void QwtDoubleRange::setValid ( bool isValid )

Set the value to be valid/invalid.

Reimplemented in QwtAbstractSlider.

Definition at line 42 of file qwt_double_range.cpp.

References isValid(), and valueChange().

{
    if ( isValid != d_isValid )
    {
        d_isValid = isValid;
        valueChange();
    }
}

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 QwtAbstractSlider, and QwtCounter.

Definition at line 150 of file qwt_double_range.cpp.

{
    setNewValue(x, false);
}

double QwtDoubleRange::step ( ) const

Returns:: the step size

See also:: setStep(), setRange()

Reimplemented in QwtCounter.

Definition at line 316 of file qwt_double_range.cpp.

References qwtAbs.

Referenced by QwtAbstractSlider::mouseReleaseEvent(), QwtDial::setScale(), and QwtAbstractSlider::timerEvent().

{
    return qwtAbs(d_step);
}

void QwtDoubleRange::stepChange ( ) [protected, virtual]

Notify a change of the step size.

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

Definition at line 308 of file qwt_double_range.cpp.

Referenced by setStep().

{
}

double QwtDoubleRange::value ( ) const

Returns the current value.

Reimplemented in QwtCounter.

Definition at line 363 of file qwt_double_range.cpp.

Referenced by QwtDial::drawContents(), QwtAnalogClock::drawNeedle(), QwtCompass::drawScaleContents(), QwtSlider::drawSlider(), QwtWheel::drawWheel(), QwtSlider::getScrollMode(), QwtDial::getValue(), QwtDial::keyPressEvent(), QwtCompass::keyPressEvent(), QwtAbstractSlider::keyPressEvent(), QwtAbstractSlider::mouseMoveEvent(), QwtAbstractSlider::mousePressEvent(), QwtAbstractSlider::mouseReleaseEvent(), QwtAbstractSlider::timerEvent(), QwtAbstractSlider::valueChange(), and QwtAbstractSlider::wheelEvent().

{ 
    return d_value; 
}

void QwtDoubleRange::valueChange ( ) [protected, virtual]

Notify a change of value.

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

Reimplemented in QwtAbstractSlider, QwtDial, QwtSlider, and QwtWheel.

Definition at line 286 of file qwt_double_range.cpp.

Referenced by setValid().

{
}

The documentation for this class was generated from the following files:

QwtDoubleRange Class Reference

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation