QwtDateScaleEngine - A scale engine for date/time values.

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Version 6.1.4                                    Wed Jan 2 2019                            QwtDateScaleEngine(3)

QwtDateScaleEngine::QwtDateScaleEngine(Qt::TimeSpectimeSpec=Qt::LocalTime)
       Constructor. The engine is initialized to build scales for the given time specification. It classifies
       intervals > 4 weeks as >= Qt::Month. The first week of a year is defined like for QwtDate::FirstThursday.

       Parameters:timeSpec Time specification

       Seealso:setTimeSpec(), setMaxWeeks(), setWeek0Type()

       A scale engine for date/time values.

       QwtDateScaleEngine builds scales from a time intervals. Together with QwtDateScaleDraw it can be used for
       axes according to date/time values.

       Years, months, weeks, days, hours and minutes are organized in steps with non constant intervals.
       QwtDateScaleEngine classifies intervals and aligns the boundaries and tick positions according to this
       classification.

       QwtDateScaleEngine supports representations depending on Qt::TimeSpec specifications. The valid range for
       scales is limited by the range of QDateTime, that differs between Qt4 and Qt5.

       Datetime values are expected as the number of milliseconds since 1970-01-01T00:00:00 Universal
       Coordinated Time - also known as 'The Epoch', that can be converted to QDateTime using
       QwtDate::toDateTime().

       Seealso:QwtDate, QwtPlot::setAxisScaleEngine(), QwtAbstractScale::setScaleEngine()

QDateTimeQwtDateScaleEngine::alignDate(constQDateTime&dateTime,doublestepSize,QwtDate::IntervalTypeintervalType,boolup)const[protected],[virtual]
       Align a date/time value for a step size

       For Qt::Day alignments there is no 'natural day 0' - instead the first day of the year is used to avoid
       jumping major ticks positions when panning a scale. For other alignments ( f.e according to the first day
       of the month ) alignDate() has to be overloaded.

       Parameters:dateTime Date/time value
           stepSize Step size
           intervalType Interval type
           up When true dateTime is ceiled - otherwise it is floored

       Returns:
           Aligned date/time value

   voidQwtDateScaleEngine::autoScale(intmaxNumSteps,double&x1,double&x2,double&stepSize)const[virtual]
       Align and divide an interval

       The algorithm aligns and divides the interval into steps.

       Datetime interval divisions are usually not equidistant and the calculated stepSize can only be used as
       an approximation for the steps calculated by divideScale().

       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)

       Seealso:QwtScaleEngine::setAttribute()

       Reimplemented from QwtLinearScaleEngine.

   QwtScaleDivQwtDateScaleEngine::divideScale(doublex1,doublex2,intmaxMajorSteps,intmaxMinorSteps,doublestepSize=0.0)const[virtual]
       Calculate a scale division for a date/time 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 scaleEngine calculates one.

       Returns:
           Calculated scale division

       Reimplemented from QwtLinearScaleEngine.

   QwtDate::IntervalTypeQwtDateScaleEngine::intervalType(constQDateTime&minDate,constQDateTime&maxDate,intmaxSteps)const[virtual]
       Classification of a date/time interval division

       Parameters:minDate Minimum ( = earlier ) of the interval
           maxDate Maximum ( = later ) of the interval
           maxSteps Maximum for the number of steps

       Returns:
           Interval classification

   intQwtDateScaleEngine::maxWeeks()constReturns:
           Upper limit for the number of weeks, when an interval can be classified as Qt::Week.

       Seealso:setMaxWeeks(), week0Type()voidQwtDateScaleEngine::setMaxWeeks(intweeks)
       Set a upper limit for the number of weeks, when an interval can be classified as Qt::Week.

       The default setting is 4 weeks.

       Parameters:weeks Upper limit for the number of weeks

       Note:
           In business charts a year is often divided into weeks [1-52]

       Seealso:maxWeeks(), setWeek0Type()voidQwtDateScaleEngine::setTimeSpec(Qt::TimeSpectimeSpec)
       Set the time specification used by the engine

       Parameters:timeSpec Time specification

       Seealso:timeSpec(), setUtcOffset(), toDateTime()voidQwtDateScaleEngine::setUtcOffset(intseconds)
       Set the offset in seconds from Coordinated Universal Time

       Parameters:seconds Offset in seconds

       Note:
           The offset has no effect beside for the time specification Qt::OffsetFromUTC.

       Seealso:
           QDate::utcOffset(), setTimeSpec(), toDateTime()voidQwtDateScaleEngine::setWeek0Type(QwtDate::Week0Typeweek0Type)
       Sets how to identify the first week of a year.

       Parameters:week0Type Mode how to identify the first week of a year

       Seealso:week0Type(), setMaxWeeks()Note:
           week0Type has no effect beside for intervals classified as QwtDate::Week.

   Qt::TimeSpecQwtDateScaleEngine::timeSpec()constReturns:
           Time specification used by the engine

       Seealso:setTimeSpec(), utcOffset(), toDateTime()QDateTimeQwtDateScaleEngine::toDateTime(doublevalue)const
       Translate a double value into a QDateTime object.

       For QDateTime result is bounded by QwtDate::minDate() and QwtDate::maxDate()Returns:
           QDateTime object initialized with timeSpec() and utcOffset().

       Seealso:timeSpec(), utcOffset(), QwtDate::toDateTime()intQwtDateScaleEngine::utcOffset()constReturns:
           Offset in seconds from Coordinated Universal Time

       Note:
           The offset has no effect beside for the time specification Qt::OffsetFromUTC.

       Seealso:
           QDate::setUtcOffset(), setTimeSpec(), toDateTime()QwtDate::Week0TypeQwtDateScaleEngine::week0Type()constReturns:
           Setting how to identify the first week of a year.

       Seealso:setWeek0Type(), maxWeeks()

       QwtDateScaleEngine - A scale engine for date/time values.

       #include <qwt_date_scale_engine.h>

       Inherits QwtLinearScaleEngine.

   PublicMemberFunctionsQwtDateScaleEngine (Qt::TimeSpec=Qt::LocalTime)
           Constructor.
       virtual ~QwtDateScaleEngine ()
           Destructor.
       void setTimeSpec (Qt::TimeSpec)
       Qt::TimeSpec timeSpec () const
       void setUtcOffset (int seconds)
       int utcOffset () const
       void setWeek0Type (QwtDate::Week0Type)
       QwtDate::Week0Typeweek0Type () const
       void setMaxWeeks (int)
       int maxWeeks () const
       virtual void autoScale (int maxNumSteps, double &x1, double &x2, double &stepSize) const
       virtual QwtScaleDivdivideScale (double x1, double x2, int maxMajorSteps, int maxMinorSteps, double
           stepSize=0.0) const
           Calculate a scale division for a date/time interval.
       virtual QwtDate::IntervalTypeintervalType (const QDateTime &, const QDateTime &, int maxSteps) const
       QDateTime toDateTime (double) const

   ProtectedMemberFunctions
       virtual QDateTime alignDate (const QDateTime &, double stepSize, QwtDate::IntervalType, bool up) const

   AdditionalInheritedMembers