QwtDateScaleDraw man page
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::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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