NAME

       QwtDateScaleDraw -

       A class for drawing datetime scales.

SYNOPSIS

       #include <qwt_date_scale_draw.h>

       Inherits QwtScaleDraw.

   Public Member Functions
       QwtDateScaleDraw (Qt::TimeSpec=Qt::LocalTime)
           Constructor.
       virtual ~QwtDateScaleDraw ()
           Destructor.
       void setDateFormat (QwtDate::IntervalType, const QString &)
       QString dateFormat (QwtDate::IntervalType) const
       void setTimeSpec (Qt::TimeSpec)
       Qt::TimeSpec timeSpec () const
       void setUtcOffset (int seconds)
       int utcOffset () const
       void setWeek0Type (QwtDate::Week0Type)
       QwtDate::Week0Type week0Type () const
       virtual QwtText label (double) const
           Convert a value into its representing label.
       QDateTime toDateTime (double) const

   Protected Member Functions
       virtual QwtDate::IntervalType intervalType (const QwtScaleDiv &) const
       virtual QString dateFormatOfDate (const QDateTime &, QwtDate::IntervalType) const

   Additional Inherited Members

Detailed Description

       A class for drawing datetime scales.

       QwtDateScaleDraw displays values as datetime labels. The format of the labels depends on
       the alignment of the major tick labels.

       The default format strings are:

       • Millisecond
          'hh:mm:ss:zzz\nddd dd MMM yyyy'

       • Second
          'hh:mm:ss\nddd dd MMM yyyy'

       • Minute
          'hh:mm\nddd dd MMM yyyy'

       • Hour
          'hh:mm\nddd dd MMM yyyy'

       • Day
          'ddd dd MMM yyyy'

       • Week
          'Www yyyy'

       • Month
          'MMM yyyy'

       • Year
          'yyyy'

       The format strings can be modified using setDateFormat() or individually for each tick
       label by overloading dateFormatOfDate(),

       Usually QwtDateScaleDraw is used in combination with QwtDateScaleEngine, that calculates
       scales for datetime intervals.

       See Also:
           QwtDateScaleEngine, QwtPlot::setAxisScaleDraw()

Constructor & Destructor Documentation

   QwtDateScaleDraw::QwtDateScaleDraw (Qt::TimeSpectimeSpec = Qt::LocalTime)
       Constructor. The default setting is to display tick labels for the given time
       specification. The first week of a year is defined like for QwtDate::FirstThursday.

       Parameters:
           timeSpec Time specification

       See Also:
           setTimeSpec(), setWeek0Type()

Member Function Documentation

   QString QwtDateScaleDraw::dateFormat (QwtDate::IntervalTypeintervalType) const
       Parameters:
           intervalType Interval type

       Returns:
           Default format string for an datetime interval type

       See Also:
           setDateFormat(), dateFormatOfDate()

   QString QwtDateScaleDraw::dateFormatOfDate (const QDateTime &dateTime,
       QwtDate::IntervalTypeintervalType) const [protected],  [virtual]
       Format string for the representation of a datetime

       dateFormatOfDate() is intended to be overloaded for situations, where formats are
       individual for specific datetime values.

       The default setting ignores dateTime and return the default format for the interval type.

       Parameters:
           dateTime Datetime value
           intervalType Interval type

       Returns:
           Format string

       See Also:
           setDateFormat(), QwtDate::toString()

   QwtDate::IntervalType QwtDateScaleDraw::intervalType (const QwtScaleDiv &scaleDiv) const
       [protected],  [virtual]
       Find the less detailed datetime unit, where no rounding errors happen.

       Parameters:
           scaleDiv Scale division

       Returns:
           Interval type

       See Also:
           dateFormatOfDate()

   QwtText QwtDateScaleDraw::label (doublevalue) const [virtual]
       Convert a value into its representing label. The value is converted to a datetime value
       using toDateTime() and converted to a plain text using QwtDate::toString().

       Parameters:
           value Value

       Returns:
           Label string.

       See Also:
           dateFormatOfDate()

       Reimplemented from QwtAbstractScaleDraw.

   void QwtDateScaleDraw::setDateFormat (QwtDate::IntervalTypeintervalType, const QString
       &format)
       Set the default format string for an datetime interval type

       Parameters:
           intervalType Interval type
           format Default format string

       See Also:
           dateFormat(), dateFormatOfDate(), QwtDate::toString()

   void QwtDateScaleDraw::setTimeSpec (Qt::TimeSpectimeSpec)
       Set the time specification used for the tick labels

       Parameters:
           timeSpec Time specification

       See Also:
           timeSpec(), setUtcOffset(), toDateTime()

   void QwtDateScaleDraw::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.

       See Also:
           QDate::utcOffset(), setTimeSpec(), toDateTime()

   void QwtDateScaleDraw::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

       See Also:
           week0Type().

       Note:
           week0Type has no effect beside for intervals classified as QwtDate::Week.

   Qt::TimeSpec QwtDateScaleDraw::timeSpec () const
       Returns:
           Time specification used for the tick labels

       See Also:
           setTimeSpec(), utcOffset(), toDateTime()

   QDateTime QwtDateScaleDraw::toDateTime (doublevalue) const
       Translate a double value into a QDateTime object.

       Returns:
           QDateTime object initialized with timeSpec() and utcOffset().

       See Also:
           timeSpec(), utcOffset(), QwtDate::toDateTime()

   int QwtDateScaleDraw::utcOffset () const
       Returns:
           Offset in seconds from Coordinated Universal Time

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

       See Also:
           QDate::setUtcOffset(), setTimeSpec(), toDateTime()

   QwtDate::Week0Type QwtDateScaleDraw::week0Type () const
       Returns:
           Setting how to identify the first week of a year.

       See Also:
           setWeek0Type()

Author

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