A scale engine for date/time values 更多...

#include <qwt_date_scale_engine.h>

类 QwtDateScaleEngine 继承关系图:

类
class	PrivateData

Public 成员函数
	QwtDateScaleEngine (Qt::TimeSpec=Qt::LocalTime)
	Constructor with time specification

	~QwtDateScaleEngine () override
	Destructor

void	setTimeSpec (Qt::TimeSpec)
	Set the time specification used by the engine

Qt::TimeSpec	timeSpec () const
	Get the time specification used by the engine

void	setUtcOffset (int seconds)
	Set the offset in seconds from Coordinated Universal Time

int	utcOffset () const
	Get the offset in seconds from Coordinated Universal Time

void	setWeek0Type (QwtDate::Week0Type)
	Set how to identify the first week of a year

QwtDate::Week0Type	week0Type () const
	Get how to identify the first week of a year

void	setMaxWeeks (int)
	Set upper limit for the number of weeks

int	maxWeeks () const
	Get upper limit for the number of weeks

virtual void	autoScale (int maxNumSteps, double &x1, double &x2, double &stepSize) const override
	Align and divide an interval

virtual QwtScaleDiv	divideScale (double x1, double x2, int maxMajorSteps, int maxMinorSteps, double stepSize=0.0) const override
	Calculate a scale division for a date/time interval

virtual QwtDate::IntervalType	intervalType (const QDateTime &, const QDateTime &, int maxSteps) const
	Classification of a date/time interval division

QDateTime	toDateTime (double) const
	Translate a double value into a QDateTime object

Public 成员函数继承自 QwtLinearScaleEngine
	QwtLinearScaleEngine (uint base=10)
	Constructor

	~QwtLinearScaleEngine () override
	Destructor

Public 成员函数继承自 QwtScaleEngine
	QwtScaleEngine (uint base=10)
	Constructor

void	setBase (uint base)
	Set the base

uint	base () const
	Return base of the scale engine

void	setAttribute (Attribute, bool on=true)
	Set an attribute

bool	testAttribute (Attribute) const
	Test if an attribute is enabled

void	setAttributes (Attributes)
	Set attributes

Attributes	attributes () const
	Return scale attributes

void	setReference (double)
	Set the reference value

double	reference () const
	Return the reference value

void	setMargins (double lower, double upper)
	Set the margins

double	lowerMargin () const
	Return the margin at the lower end of the scale

double	upperMargin () const
	Return the margin at the upper end of the scale

void	setTransformation (QwtTransform *)
	Set the transformation

QwtTransform *	transformation () const
	Create and return a clone of the transformation of the engine

Protected 成员函数
virtual QDateTime	alignDate (const QDateTime &, double stepSize, QwtDate::IntervalType, bool up) const
	Align a date/time value for a step size

Protected 成员函数继承自 QwtLinearScaleEngine
QwtInterval	align (const QwtInterval &, double stepSize) const
	Align an interval to a step size

void	buildTicks (const QwtInterval &, double stepSize, int maxMinorSteps, QList< double > ticks[QwtScaleDiv::NTickTypes]) const
	Calculate ticks for an interval

QList< double >	buildMajorTicks (const QwtInterval &interval, double stepSize) const
	Calculate major ticks for an interval

void	buildMinorTicks (const QList< double > &majorTicks, int maxMinorSteps, double stepSize, QList< double > &minorTicks, QList< double > &mediumTicks) const
	Calculate minor/medium ticks for major ticks

Protected 成员函数继承自 QwtScaleEngine
bool	contains (const QwtInterval &, double value) const
	Check if an interval contains a value

QList< double >	strip (const QList< double > &, const QwtInterval &) const
	Strip values outside an interval

double	divideInterval (double intervalSize, int numSteps) const
	Divide an interval

QwtInterval	buildInterval (double value) const
	Build an interval around a value

额外继承的成员函数
Public 类型继承自 QwtScaleEngine
enum	Attribute { NoAttribute = 0x00 , IncludeReference = 0x01 , Symmetric = 0x02 , Floating = 0x04 , Inverted = 0x08 }
	Layout attributes 更多...

详细描述

A scale engine for date/time values

QwtDateScaleEngine builds scales from time intervals. Together with QwtDateScaleDraw it can be used for axes according to date/time values.

Years, months, weeks, days, hours and minutes are organized in steps with non constant intervals. QwtDateScaleEngine classifies intervals and aligns the boundaries and tick positions according to this classification.

QwtDateScaleEngine supports representations depending on Qt::TimeSpec specifications. The valid range for scales is limited by the range of QDateTime, that differs between Qt4 and Qt5.

Datetime values are expected as the number of milliseconds since 1970-01-01T00:00:00 Universal Coordinated Time - also known as "The Epoch", that can be converted to QDateTime using QwtDate::toDateTime().

参见: QwtDate, QwtPlot::setAxisScaleEngine(), QwtAbstractScale::setScaleEngine()

构造及析构函数说明

◆ QwtDateScaleEngine()

QwtDateScaleEngine::QwtDateScaleEngine ( Qt::TimeSpec timeSpec = Qt::LocalTime )

explicit

Constructor with time specification

Constructor

The engine is initialized to build scales for the given time specification. It classifies intervals > 4 weeks as >= Qt::Month. The first week of a year is defined like for QwtDate::FirstThursday.

参数

[in] timeSpec Time specification

参见: setTimeSpec(), setMaxWeeks(), setWeek0Type()

成员函数说明

◆ alignDate()

QDateTime QwtDateScaleEngine::alignDate	(	const QDateTime &	dateTime,
		double	stepSize,
		QwtDate::IntervalType	intervalType,
		bool	up
	)		const

protectedvirtual

Align a date/time value for a step size

For Qt::Day alignments there is no "natural day 0" - instead the first day of the year is used to avoid jumping major ticks positions when panning a scale. For other alignments ( f.e according to the first day of the month ) alignDate() has to be overloaded.

参数

dateTime	Date/time value
stepSize	Step size
intervalType	Interval type
up	When true dateTime is ceiled - otherwise it is floored

返回: Aligned date/time value

◆ autoScale()

void QwtDateScaleEngine::autoScale	(	int	maxNumSteps,
		double &	x1,
		double &	x2,
		double &	stepSize
	)		const

overridevirtual

Align and divide an interval

The algorithm aligns and divides the interval into steps. Datetime interval divisions are usually not equidistant and the calculated stepSize can only be used as an approximation for the steps calculated by divideScale().

参数

[in]	maxNumSteps	Max. number of steps
[out]	x1	First limit of the interval (In/Out)
[out]	x2	Second limit of the interval (In/Out)
[out]	stepSize	Step size (Out)

参见: QwtScaleEngine::setAttribute()

重载 QwtLinearScaleEngine .

◆ divideScale()

QwtScaleDiv QwtDateScaleEngine::divideScale	(	double	x1,
		double	x2,
		int	maxMajorSteps,
		int	maxMinorSteps,
		double	stepSize = `0.0`
	)		const

overridevirtual

Calculate a scale division for a date/time interval

参数

[in]	x1	First interval limit
[in]	x2	Second interval limit
[in]	maxMajorSteps	Maximum for the number of major steps
[in]	maxMinorSteps	Maximum number of minor steps
[in]	stepSize	Step size. If stepSize == 0, the scaleEngine calculates one.

返回: Calculated scale division

重载 QwtLinearScaleEngine .

◆ intervalType()

QwtDate::IntervalType QwtDateScaleEngine::intervalType	(	const QDateTime &	minDate,
		const QDateTime &	maxDate,
		int	maxSteps
	)		const

virtual

Classification of a date/time interval division

参数

[in]	minDate	Minimum ( = earlier ) of the interval
[in]	maxDate	Maximum ( = later ) of the interval
[in]	maxSteps	Maximum for the number of steps

返回: Interval classification

◆ maxWeeks()

int QwtDateScaleEngine::maxWeeks ( ) const

Get upper limit for the number of weeks

Get the upper limit for the number of weeks

返回: Upper limit for the number of weeks, when an interval can be classified as Qt::Week

参见: setMaxWeeks(), week0Type()

◆ setMaxWeeks()

void QwtDateScaleEngine::setMaxWeeks ( int weeks )

Set upper limit for the number of weeks

Set an upper limit for the number of weeks

Set an upper limit for the number of weeks, when an interval can be classified as Qt::Week. The default setting is 4 weeks.

参数

[in] weeks Upper limit for the number of weeks

注解: In business charts a year is often divided into weeks [1-52]

参见: maxWeeks(), setWeek0Type()

◆ setTimeSpec()

void QwtDateScaleEngine::setTimeSpec ( Qt::TimeSpec timeSpec )

Set the time specification used by the engine

参数

[in] timeSpec Time specification

参见: timeSpec(), setUtcOffset(), toDateTime()

◆ setUtcOffset()

void QwtDateScaleEngine::setUtcOffset ( int seconds )

Set the offset in seconds from Coordinated Universal Time

参数

[in] seconds Offset in seconds

注解: The offset has no effect beside for the time specification Qt::OffsetFromUTC.

参见: utcOffset(), setTimeSpec(), toDateTime()

◆ setWeek0Type()

void QwtDateScaleEngine::setWeek0Type ( QwtDate::Week0Type week0Type )

Set how to identify the first week of a year

参数

[in] week0Type Mode how to identify the first week of a year

注解: week0Type has no effect beside for intervals classified as QwtDate::Week.

参见: week0Type(), setMaxWeeks()

◆ timeSpec()

Qt::TimeSpec QwtDateScaleEngine::timeSpec ( ) const

Get the time specification used by the engine

返回: Time specification used by the engine

参见: setTimeSpec(), utcOffset(), toDateTime()

◆ toDateTime()

QDateTime QwtDateScaleEngine::toDateTime ( double value ) const

Translate a double value into a QDateTime object

For QDateTime result is bounded by QwtDate::minDate() and QwtDate::maxDate()

参数

[in] value Double value to convert

返回: QDateTime object initialized with timeSpec() and utcOffset()

参见: timeSpec(), utcOffset(), QwtDate::toDateTime()

◆ utcOffset()

int QwtDateScaleEngine::utcOffset ( ) const

Get the offset in seconds from Coordinated Universal Time

返回: Offset in seconds from Coordinated Universal Time

注解: The offset has no effect beside for the time specification Qt::OffsetFromUTC.

参见: setUtcOffset(), setTimeSpec(), toDateTime()

◆ week0Type()

QwtDate::Week0Type QwtDateScaleEngine::week0Type ( ) const

Get how to identify the first week of a year

返回: Setting how to identify the first week of a year

参见: setWeek0Type(), maxWeeks()

该类的文档由以下文件生成:

/home/runner/work/QWT/QWT/src/plot/qwt_date_scale_engine.h
/home/runner/work/QWT/QWT/src/plot/qwt_date_scale_engine.cpp

类

Public 成员函数

Protected 成员函数

额外继承的成员函数

详细描述

构造及析构函数说明

◆ QwtDateScaleEngine()

成员函数说明

◆ alignDate()

◆ autoScale()

◆ divideScale()

◆ intervalType()

◆ maxWeeks()

◆ setMaxWeeks()

◆ setTimeSpec()

◆ setUtcOffset()

◆ setWeek0Type()

◆ timeSpec()

◆ toDateTime()

◆ utcOffset()

◆ week0Type()