Specialized axis ticker for calendar dates and times as axis ticks. More...

Inheritance diagram for QCPAxisTickerDateTime:

Public Member Functions
	QCPAxisTickerDateTime ()
	Constructs the ticker and sets reasonable default values.

QString	dateTimeFormat () const

Qt::TimeSpec	dateTimeSpec () const

void	setDateTimeFormat (const QString &format)
	Sets the format in which dates and times are displayed as tick labels.

void	setDateTimeSpec (Qt::TimeSpec spec)
	Sets the time spec that is used for creating the tick labels from corresponding dates/times.

void	setTickOrigin (double origin)
	Sets the tick origin (see QCPAxisTicker::setTickOrigin) in seconds since Epoch (1.

void	setTickOrigin (const QDateTime &origin)
	Sets the tick origin (see QCPAxisTicker::setTickOrigin) as a QDateTime origin.

Public Member Functions inherited from QCPAxisTicker
	QCPAxisTicker ()
	Constructs the ticker and sets reasonable default values.

TickStepStrategy	tickStepStrategy () const

int	tickCount () const

double	tickOrigin () const

void	setTickStepStrategy (TickStepStrategy strategy)
	Sets which strategy the axis ticker follows when choosing the size of the tick step.

void	setTickCount (int count)
	Sets how many ticks this ticker shall aim to generate across the axis range.

void	setTickOrigin (double origin)
	Sets the mathematical coordinate (or "offset") of the zeroth tick.

virtual void	generate (const QCPRange &range, const QLocale &locale, QChar formatChar, int precision, QVector< double > &ticks, QVector< double > subTicks, QVector< QString > tickLabels)
	This is the method called by QCPAxis in order to actually generate tick coordinates (ticks), tick label strings (tickLabels) and sub tick coordinates (subTicks).

Static Public Member Functions
static QDateTime	keyToDateTime (double key)
	A convenience method which turns key (in seconds since Epoch 1.

static double	dateTimeToKey (const QDateTime dateTime)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.A convenience method which turns a QDateTime object into a double value that corresponds to seconds since Epoch (1.

static double	dateTimeToKey (const QDate date)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.A convenience method which turns a QDate object into a double value that corresponds to seconds since Epoch (1.

Protected Types
enum	DateStrategy { dsNone , dsUniformTimeInDay , dsUniformDayInMonth }

Protected Member Functions
virtual double	getTickStep (const QCPRange &range) Q_DECL_OVERRIDE

virtual int	getSubTickCount (double tickStep) Q_DECL_OVERRIDE

virtual QString	getTickLabel (double tick, const QLocale &locale, QChar formatChar, int precision) Q_DECL_OVERRIDE

virtual QVector< double >	createTickVector (double tickStep, const QCPRange &range) Q_DECL_OVERRIDE

Protected Member Functions inherited from QCPAxisTicker
virtual double	getTickStep (const QCPRange &range)

virtual int	getSubTickCount (double tickStep)

virtual QString	getTickLabel (double tick, const QLocale &locale, QChar formatChar, int precision)

virtual QVector< double >	createTickVector (double tickStep, const QCPRange &range)

virtual QVector< double >	createSubTickVector (int subTickCount, const QVector< double > &ticks)

virtual QVector< QString >	createLabelVector (const QVector< double > &ticks, const QLocale &locale, QChar formatChar, int precision)

void	trimTicks (const QCPRange &range, QVector< double > &ticks, bool keepOneOutlier) const

double	pickClosest (double target, const QVector< double > &candidates) const

double	getMantissa (double input, double *magnitude=0) const

double	cleanMantissa (double input) const

Protected Attributes
QString	mDateTimeFormat

Qt::TimeSpec	mDateTimeSpec

enum QCPAxisTickerDateTime::DateStrategy	mDateStrategy

Protected Attributes inherited from QCPAxisTicker
TickStepStrategy	mTickStepStrategy

int	mTickCount

double	mTickOrigin

Additional Inherited Members
Public Types inherited from QCPAxisTicker
enum	TickStepStrategy { tssReadability , tssMeetTickCount }
	Defines the strategies that the axis ticker may follow when choosing the size of the tick step. More...

Detailed Description

Specialized axis ticker for calendar dates and times as axis ticks.

This QCPAxisTicker subclass generates ticks that correspond to real calendar dates and times. The plot axis coordinate is interpreted as Unix Time, so seconds since Epoch (January 1, 1970, 00:00 UTC). This is also used for example by QDateTime in the toTime_t()/setTime_t() methods with a precision of one second. Since Qt 4.7, millisecond accuracy can be obtained from QDateTime by using QDateTime::fromMSecsSinceEpoch()/1000.0. The static methods dateTimeToKey and keyToDateTime conveniently perform this conversion achieving a precision of one millisecond on all Qt versions.

The format of the date/time display in the tick labels is controlled with setDateTimeFormat. If a different time spec (time zone) shall be used, see setDateTimeSpec.

This ticker produces unequal tick spacing in order to provide intuitive date and time-of-day ticks. For example, if the axis range spans a few years such that there is one tick per year, ticks will be positioned on 1. January of every year. This is intuitive but, due to leap years, will result in slightly unequal tick intervals (visually unnoticeable). The same can be seen in the image above: even though the number of days varies month by month, this ticker generates ticks on the same day of each month.

If you would like to change the date/time that is used as a (mathematical) starting date for the ticks, use the setTickOrigin(const QDateTime &origin) method overload, which takes a QDateTime. If you pass 15. July, 9:45 to this method, the yearly ticks will end up on 15. July at 9:45 of every year.

The ticker can be created and assigned to an axis like this:

Note: If you rather wish to display relative times in terms of days, hours, minutes, seconds and milliseconds, and are not interested in the intricacies of real calendar dates with months and (leap) years, have a look at QCPAxisTickerTime instead.

Constructor & Destructor Documentation

◆ QCPAxisTickerDateTime()

QCPAxisTickerDateTime::QCPAxisTickerDateTime ( )

Constructs the ticker and sets reasonable default values.

Axis tickers are commonly created managed by a QSharedPointer, which then can be passed to QCPAxis::setTicker.

Member Function Documentation

◆ createTickVector()

QVector< double > QCPAxisTickerDateTime::createTickVector	(	double	tickStep,
		const QCPRange &	range
	)

protectedvirtual

Reimplemented from QCPAxisTicker.

◆ dateTimeToKey() [1/2]

double QCPAxisTickerDateTime::dateTimeToKey ( const QDate date )

static

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.A convenience method which turns a QDate object into a double value that corresponds to seconds since Epoch (1.

Jan 1970, 00:00 UTC). This is the format used as axis coordinates by QCPAxisTickerDateTime.

See also: keyToDateTime

◆ dateTimeToKey() [2/2]

double QCPAxisTickerDateTime::dateTimeToKey ( const QDateTime dateTime )

static

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.A convenience method which turns a QDateTime object into a double value that corresponds to seconds since Epoch (1.

Jan 1970, 00:00 UTC). This is the format used as axis coordinates by QCPAxisTickerDateTime.

The accuracy achieved by this method is one millisecond, irrespective of the used Qt version (it works around the lack of a QDateTime::toMSecsSinceEpoch in Qt 4.6)

See also: keyToDateTime

◆ getSubTickCount()

int QCPAxisTickerDateTime::getSubTickCount ( double tickStep )

protectedvirtual

Reimplemented from QCPAxisTicker.

◆ getTickLabel()

QString QCPAxisTickerDateTime::getTickLabel	(	double	tick,
		const QLocale &	locale,
		QChar	formatChar,
		int	precision
	)

protectedvirtual

Reimplemented from QCPAxisTicker.

◆ getTickStep()

double QCPAxisTickerDateTime::getTickStep ( const QCPRange & range )

protectedvirtual

Reimplemented from QCPAxisTicker.

◆ keyToDateTime()

QDateTime QCPAxisTickerDateTime::keyToDateTime ( double key )

static

A convenience method which turns key (in seconds since Epoch 1.

Jan 1970, 00:00 UTC) into a QDateTime object. This can be used to turn axis coordinates to actual QDateTimes.

The accuracy achieved by this method is one millisecond, irrespective of the used Qt version (it works around the lack of a QDateTime::fromMSecsSinceEpoch in Qt 4.6)

See also: dateTimeToKey

◆ setDateTimeFormat()

void QCPAxisTickerDateTime::setDateTimeFormat ( const QString & format )

Sets the format in which dates and times are displayed as tick labels.

For details about the format string, see the documentation of QDateTime::toString().

Newlines can be inserted with "\n".

See also: setDateTimeSpec

◆ setDateTimeSpec()

void QCPAxisTickerDateTime::setDateTimeSpec ( Qt::TimeSpec spec )

Sets the time spec that is used for creating the tick labels from corresponding dates/times.

The default value of QDateTime objects (and also QCPAxisTickerDateTime) is Qt::LocalTime. However, if the date time values passed to QCustomPlot (e.g. in the form of axis ranges or keys of a plottable) are given in the UTC spec, set spec to Qt::UTC to get the correct axis labels.

See also: setDateTimeFormat

◆ setTickOrigin() [1/2]

void QCPAxisTickerDateTime::setTickOrigin ( const QDateTime & origin )

Sets the tick origin (see QCPAxisTicker::setTickOrigin) as a QDateTime origin.

This is useful to define the month/day/time recurring at greater tick interval steps. For example, If you pass 15. July, 9:45 to this method and the tick interval happens to be one tick per year, the ticks will end up on 15. July at 9:45 of every year.

◆ setTickOrigin() [2/2]

void QCPAxisTickerDateTime::setTickOrigin ( double origin )

Sets the tick origin (see QCPAxisTicker::setTickOrigin) in seconds since Epoch (1.

Jan 1970, 00:00 UTC). For the date time ticker it might be more intuitive to use the overload which directly takes a QDateTime, see setTickOrigin(const QDateTime &origin).

This is useful to define the month/day/time recurring at greater tick interval steps. For example, If you pass 15. July, 9:45 to this method and the tick interval happens to be one tick per year, the ticks will end up on 15. July at 9:45 of every year.

The documentation for this class was generated from the following files:

qcustomplot.h
qcustomplot.cpp

Public Member Functions

Static Public Member Functions

Protected Types

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QCPAxisTickerDateTime()

Member Function Documentation

◆ createTickVector()

◆ dateTimeToKey() [1/2]

◆ dateTimeToKey() [2/2]

◆ getSubTickCount()

◆ getTickLabel()

◆ getTickStep()

◆ keyToDateTime()

◆ setDateTimeFormat()

◆ setDateTimeSpec()

◆ setTickOrigin() [1/2]

◆ setTickOrigin() [2/2]