AstroCalcChart Class Reference

This class extends QChart and encapsulates data for the Altitude vs. More...

#include <AstroCalcChart.hpp>

Public Types
enum	Series {   AltVsTime , CurrentTime , TransitTime , SunElevation ,   CivilTwilight , NauticalTwilight , AstroTwilight , Moon ,   AzVsTime , MonthlyElevation , AngularSize1 , Declination1 ,   Distance1 , Elongation1 , HeliocentricDistance1 , Magnitude1 ,   PhaseAngle1 , Phase1 , RightAscension1 , TransitAltitude1 ,   AngularSize2 , Declination2 , Distance2 , Elongation2 ,   HeliocentricDistance2 , Magnitude2 , PhaseAngle2 , Phase2 ,   RightAscension2 , TransitAltitude2 , LunarElongation , LunarElongationLimit ,   pcDistanceAU , pcDistanceDeg }

Public Slots
virtual void	retranslate ()
void	showToolTip (const QPointF &point, bool show)
	A slot to connect the hovered signal from a series to. More...

Public Member Functions
	AstroCalcChart (QSet< AstroCalcChart::Series > which)
void	append (Series s, qint64 x, qreal y)
	Append one pair of data values to series s. x must be some QDateTime.toMSecsSinceEpoch()
void	replace (Series s, int index, qreal x, qreal y)
	Replace one pair of data values to series s at position index.
void	clear (Series s)
	Reset (delete and create new empty) series s.
int	lengthOfSeries (Series s) const
void	show (Series s)
	Activate series s. More...
void	setYrange (Series series, qreal min, qreal max, bool strictMin=false)
	Set range of Y axis required by the Y values of series. More...
void	setYrange (Series series, QPair< double, double > yRange, bool strictMin=false)
	Convenience function.
void	setYrangeR (Series series, qreal min, qreal max)
	Set range of Y axis on the right side required by the Y values of series. Do not set buffers or logical limits here, these are determined in this function.
void	setYrangeR (Series series, QPair< double, double > yRangeR)
	Convenience function.
QPair< double, double >	findYRange (const Series series) const
	Find range of values for the respective series plot.
QPair< double, double >	findYMax (const Series series) const
	Find x/y values where y=max for the respective series plot.
void	setupAxes (const double jd, const int periods, const QString &englishName)
	Setup axes and appearance. More...
void	drawTrivialLineX (Series s, const qreal x)
	Draw a 2-point vertical line at x which extends over the whole graph.
void	drawTrivialLineY (Series s, const qreal y)
	Draw a 2-point horizontal line at y which extends over the whole graph.

Protected Member Functions
void	mousePressEvent (QGraphicsSceneMouseEvent *event) override
	Override. This sets the time from the click point to the main application.

Detailed Description

This class extends QChart and encapsulates data for the Altitude vs.

Time and the other line Charts in AstroCalcDialog. Most lines can be QSplineSeries, however the azimuth and magnitude lines must use QLineSeries to avoid a "spline tremor" at the 0/360° transition or where some moon enters the shadow of its planet.

Additional features:

• Mouse-over on series provides date/value information in a tooltip
• Left mouse click sets date/time of click point.

The correct sequence of use:

• create with the possible series you are going to use
• fill the series with values with append(). The X value is milliseconds from Epoch (1970).
• add horizontal/vertical lines with addTrivial[YX]Line(series)
• call show(series)
• scale the Y axes: – You can retrieve the actual min/max values from findYRange(series). Apply any manual limits last. – call setYrange(series, min, max) and setYrangeR(series, min, max) where needed. Use real min/max. A series-dependent buffer will be added.
• call setupAxes()
• use setChart() to display chart in a chartView. A previous chart must be retrieved and deleted!

The time coordinate is displayed using a QDateTimeAxis. Given slight differences between QDateTime and Stellarium's understanding of timezones etc., we must circumvent Qt's automatic handling of local timezones and work as if the time axis would display UTC dates, however, the actual data are in our own timezone frame. This requires manipulation of the x values: From the data which are computed in JD, plot them in UT+zoneOffset. Clicked time is delivered as "UT" and must add zoneOffset as well.

Note

We are using QDateTime here. Currently we have no handling for years before 1AD. Qt has no year zero, we have it. Qt time scaling may also show use pf Proleptic Gregorian calendars. We must expect to see a few weird dates before 1AD or even before 1582.

Member Function Documentation

lengthOfSeries()

int AstroCalcChart::lengthOfSeries

(

Series

s

)

const

Returns

length of series s. If chart does not contain s, returns -1.

setupAxes()

void AstroCalcChart::setupAxes	(	const double	jd,
		const int	periods,
		const QString &	englishName
	)

Setup axes and appearance.

Call this at the end of drawing, just before display but after all series have been activated with show().

• englishName used for details in the two-graph charts. Use an empty string otherwise.

setYrange()

void AstroCalcChart::setYrange	(	Series	series,
		qreal	min,
		qreal	max,
		bool	strictMin = false
	)

Set range of Y axis required by the Y values of series.

Do not set buffers or logical limits here, these are determined in this function.

• strictMin: The altVsTime plot may require strict minimum setting without buffer. Use false (default) for other plots.

show()

void AstroCalcChart::show

(

Series

s

)

Activate series s.

It must have been filled using append(s, ., .) before. Make sure to call setupAxes() after calling show!

showToolTip

void AstroCalcChart::showToolTip ( const QPointF &  point, bool  show  )

slot

A slot to connect the hovered signal from a series to.

It shows the value of the series in a Tooltip on mouse-over.

Note

it only shows values of a point where the mouse is over. The vertical lines for "now" and "transit" are currently unavailable.