QwtDoubleInterval(3) A class representing an interval.


#include <qwt_double_interval.h>

Public Types

enum BorderMode { IncludeBorders = 0, ExcludeMinimum = 1, ExcludeMaximum = 2, ExcludeBorders = ExcludeMinimum | ExcludeMaximum }

Public Member Functions

int borderFlags () const

bool contains (double value) const

QwtDoubleInterval extend (double value) const

QwtDoubleInterval intersect (const QwtDoubleInterval &) const

bool intersects (const QwtDoubleInterval &) const

void invalidate ()

QwtDoubleInterval inverted () const

bool isNull () const

bool isValid () const

QwtDoubleInterval limited (double minValue, double maxValue) const

double maxValue () const

double minValue () const

QwtDoubleInterval normalized () const

int operator!= (const QwtDoubleInterval &) const

QwtDoubleInterval operator& (const QwtDoubleInterval &) const

QwtDoubleInterval & operator&= (const QwtDoubleInterval &)

int operator== (const QwtDoubleInterval &) const

QwtDoubleInterval operator| (double) const

QwtDoubleInterval operator| (const QwtDoubleInterval &) const

QwtDoubleInterval & operator|= (double)

QwtDoubleInterval & operator|= (const QwtDoubleInterval &)

QwtDoubleInterval (double minValue, double maxValue, int borderFlags=IncludeBorders)

QwtDoubleInterval ()

void setBorderFlags (int)

void setInterval (double minValue, double maxValue, int borderFlags=IncludeBorders)

void setMaxValue (double)

void setMinValue (double)

QwtDoubleInterval symmetrize (double value) const

QwtDoubleInterval unite (const QwtDoubleInterval &) const

double width () const

Detailed Description

A class representing an interval.

The interval is represented by 2 doubles, the lower and the upper limit.

Member Enumeration Documentation

enum QwtDoubleInterval::BorderModeFlag indicating if a border is included/excluded from an interval

  • IncludeBorders

     min/max values are inside the interval
  • ExcludeMinimum

     min value is not included in the interval
  • ExcludeMaximum

     max value is not included in the interval
  • ExcludeBorders

     min/max values are not included in the interval

See also:

setBorderMode(), testBorderMode()

Constructor & Destructor Documentation

QwtDoubleInterval::QwtDoubleInterval () [inline]

Default Constructor. Creates an invalid interval [0.0, -1.0]

See also:

setInterval(), isValid()

QwtDoubleInterval::QwtDoubleInterval (doubleminValue, doublemaxValue, intborderFlags = IncludeBorders) [inline]Constructor

Build an interval with from min/max values


minValue Minimum value
maxValue Maximum value
borderFlags Include/Exclude borders

Member Function Documentation

int QwtDoubleInterval::borderFlags () const [inline]Returns:

Border flags

See also:


bool QwtDoubleInterval::contains (doublevalue) constTest if a value is inside an interval


value Value


true, if value >= minValue() && value <= maxValue()

QwtDoubleInterval QwtDoubleInterval::extend (doublevalue) constExtend the interval

If value is below minValue, value becomes the lower limit. If value is above maxValue, value becomes the upper limit.

extend has no effect for invalid intervals


value Value

See also:


QwtDoubleInterval QwtDoubleInterval::intersect (const QwtDoubleInterval &other) const

Intersect 2 intervals.

bool QwtDoubleInterval::intersects (const QwtDoubleInterval &other) constTest if two intervals overlap

void QwtDoubleInterval::invalidate () [inline]Invalidate the interval

The limits are set to interval [0.0, -1.0]

See also:


QwtDoubleInterval QwtDoubleInterval::inverted () constInvert the limits of the interval


Inverted interval

See also:


bool QwtDoubleInterval::isNull () const [inline]Returns:

true, if isValid() && (minValue() >= maxValue())

bool QwtDoubleInterval::isValid () const [inline]A interval is valid when minValue() <= maxValue(). In case of QwtDoubleInterval::ExcludeBorders it is true when minValue() < maxValue()

QwtDoubleInterval QwtDoubleInterval::limited (doublelowerBound, doubleupperBound) constLimit the interval, keeping the border modes


lowerBound Lower limit
upperBound Upper limit


Limited interval

double QwtDoubleInterval::maxValue () const [inline]Returns:

Upper limit of the interval

double QwtDoubleInterval::minValue () const [inline]Returns:

Lower limit of the interval

QwtDoubleInterval QwtDoubleInterval::normalized () const

Normalize the limits of the interval. If maxValue() < minValue() the limits will be inverted.


Normalized interval

See also:

isValid(), inverted()

int QwtDoubleInterval::operator!= (const QwtDoubleInterval &other) const [inline]

Compare two intervals.

QwtDoubleInterval QwtDoubleInterval::operator& (const QwtDoubleInterval &interval) const [inline]Intersection of two intervals

See also:


QwtDoubleInterval & QwtDoubleInterval::operator&= (const QwtDoubleInterval &interval)

Intersects this interval with the given interval.

int QwtDoubleInterval::operator== (const QwtDoubleInterval &other) const [inline]

Compare two intervals.

QwtDoubleInterval QwtDoubleInterval::operator| (const QwtDoubleInterval &interval) const [inline]Union of two intervals

See also:


QwtDoubleInterval QwtDoubleInterval::operator| (doublevalue) const [inline]Extend an interval

See also:


QwtDoubleInterval & QwtDoubleInterval::operator|= (const QwtDoubleInterval &interval)

Unites this interval with the given interval.

void QwtDoubleInterval::setBorderFlags (intborderFlags) [inline]Change the border flags


borderFlags Or'd BorderMode flags

See also:


void QwtDoubleInterval::setInterval (doubleminValue, doublemaxValue, intborderFlags = IncludeBorders) [inline]Assign the limits of the interval


minValue Minimum value
maxValue Maximum value
borderFlags Include/Exclude borders

void QwtDoubleInterval::setMaxValue (doublemaxValue) [inline]Assign the upper limit of the interval


maxValue Maximum value

void QwtDoubleInterval::setMinValue (doubleminValue) [inline]Assign the lower limit of the interval


minValue Minimum value

QwtDoubleInterval QwtDoubleInterval::symmetrize (doublevalue) constAdjust the limit that is closer to value, so that value becomes the center of the interval.


value Center


Interval with value as center

QwtDoubleInterval QwtDoubleInterval::unite (const QwtDoubleInterval &other) const

Unite 2 intervals.

double QwtDoubleInterval::width () const [inline]Return the width of an interval The width of invalid intervals is 0.0, otherwise the result is maxValue() - minValue().

See also:



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