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:
- 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::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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