QwtDateScaleDraw - Man Page

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:

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::TimeSpec timeSpec = 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::IntervalType intervalType) 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::IntervalType intervalType) 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 (double value) 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::IntervalType intervalType, 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::TimeSpec timeSpec)

Set the time specification used for the tick labels

Parameters

timeSpec Time specification

See also

timeSpec(), setUtcOffset(), toDateTime()

void QwtDateScaleDraw::setUtcOffset (int seconds)

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::Week0Type week0Type)

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 (double value) 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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Info

Mon Jun 1 2020 Version 6.1.5 Qwt User's Guide