Qwt User's Guide
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A class for drawing datetime scales. More...
#include <qwt_date_scale_draw.h>
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 |
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.
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.
timeSpec | Time specification |
QString QwtDateScaleDraw::dateFormat | ( | QwtDate::IntervalType | intervalType | ) | const |
intervalType | Interval type |
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.
dateTime | Datetime value |
intervalType | Interval type |
QwtDate::IntervalType QwtDateScaleDraw::intervalType | ( | const QwtScaleDiv & | scaleDiv | ) | const [protected, virtual] |
Find the less detailed datetime unit, where no rounding errors happen.
scaleDiv | Scale division |
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().
value | Value |
Reimplemented from QwtAbstractScaleDraw.
void QwtDateScaleDraw::setDateFormat | ( | QwtDate::IntervalType | intervalType, |
const QString & | format | ||
) |
Set the default format string for an datetime interval type
intervalType | Interval type |
format | Default format string |
void QwtDateScaleDraw::setTimeSpec | ( | Qt::TimeSpec | timeSpec | ) |
Set the time specification used for the tick labels
timeSpec | Time specification |
void QwtDateScaleDraw::setUtcOffset | ( | int | seconds | ) |
Set the offset in seconds from Coordinated Universal Time
seconds | Offset in seconds |
void QwtDateScaleDraw::setWeek0Type | ( | QwtDate::Week0Type | week0Type | ) |
Sets how to identify the first week of a year.
week0Type | Mode how to identify the first week of a year |
Qt::TimeSpec QwtDateScaleDraw::timeSpec | ( | ) | const |
QDateTime QwtDateScaleDraw::toDateTime | ( | double | value | ) | const |
Translate a double value into a QDateTime object.
int QwtDateScaleDraw::utcOffset | ( | ) | const |