EquirectangularProjector Class Reference

#include <equirectangularprojector.h>

Inheritance diagram for EquirectangularProjector:

Public Member Functions
	EquirectangularProjector (const ViewParams &p)
SkyPoint	fromScreen (const QPointF &p, dms *LST, const dms *lat, bool onlyAltAz=false) const override
QVector< Eigen::Vector2f >	groundPoly (SkyPoint *labelpoint=nullptr, bool *drawLabel=nullptr) const override
double	radius () const override
Eigen::Vector2f	toScreenVec (const SkyPoint *o, bool oRefract=true, bool *onVisibleHemisphere=nullptr) const override
Projection	type () const override
bool	unusablePoint (const QPointF &p) const override
void	updateClipPoly () override
Public Member Functions inherited from Projector
	Projector (const ViewParams &p)
bool	checkVisibility (const SkyPoint *p) const
QPointF	clipLine (SkyPoint *p1, SkyPoint *p2) const
Eigen::Vector2f	clipLineVec (SkyPoint *p1, SkyPoint *p2) const
virtual QPolygonF	clipPoly () const
double	findNorthPA (const SkyPoint *o, float x, float y) const
double	findPA (const SkyObject *o, float x, float y) const
double	findZenithPA (const SkyPoint *o, float x, float y) const
double	fov () const
bool	onScreen (const Eigen::Vector2f &p) const
bool	onScreen (const QPointF &p) const
void	setViewParams (const ViewParams &p)
QPointF	toScreen (const SkyPoint *o, bool oRefract=true, bool *onVisibleHemisphere=nullptr) const
ViewParams	viewParams () const

Additional Inherited Members
Public Types inherited from Projector
enum	Projection {   Lambert , AzimuthalEquidistant , Orthographic , Equirectangular ,   Stereographic , Gnomonic , UnknownProjection }
Protected Member Functions inherited from Projector
virtual double	cosMaxFieldAngle () const
Eigen::Vector2f	derst (double x, double y) const
virtual double	projectionK (double x) const
virtual double	projectionL (double x) const
Eigen::Vector2f	rst (double x, double y) const
Static Protected Member Functions inherited from Projector
static SkyPoint	pointAt (double az)
Protected Attributes inherited from Projector
QPolygonF	m_clipPolygon
double	m_cosY0 { 0 }
KStarsData *	m_data { nullptr }
double	m_fov { 0 }
double	m_sinY0 { 0 }
ViewParams	m_vp

Detailed Description

Implememntation of Equirectangular projection

Definition at line 18 of file equirectangularprojector.h.

Constructor & Destructor Documentation

EquirectangularProjector()

EquirectangularProjector::EquirectangularProjector ( const ViewParams & p )

explicit

Definition at line 13 of file equirectangularprojector.cpp.

Member Function Documentation

fromScreen()

SkyPoint EquirectangularProjector::fromScreen ( const QPointF & p, dms * LST, const dms * lat, bool onlyAltAz = false ) const

overridevirtual

Determine RA, Dec coordinates of the pixel at (dx, dy), which are the screen pixel coordinate offsets from the center of the Sky pixmap.

Parameters

p	the screen pixel position to convert
LST	pointer to the local sidereal time, as a dms object.
lat	pointer to the current geographic laitude, as a dms object
onlyAltAz	the returned SkyPoint's RA & DEC are not computed, only Alt/Az.

N.B. We don't cache these sin/cos values in the inverse projection because it causes 'shaking' when moving the sky.

Reimplemented from Projector.

Definition at line 63 of file equirectangularprojector.cpp.

groundPoly()

QVector< Eigen::Vector2f > EquirectangularProjector::groundPoly ( SkyPoint * labelpoint = nullptr, bool * drawLabel = nullptr ) const

overridevirtual

Get the ground polygon.

Parameters

labelpoint	This point will be set to something suitable for attaching a label
drawLabel	this tells whether to draw a label.

Returns

the ground polygon

Reimplemented from Projector.

Definition at line 105 of file equirectangularprojector.cpp.

radius()

double EquirectangularProjector::radius ( ) const

overridevirtual

Get the radius of this projection's sky circle.

Returns

the radius in radians

Reimplemented from Projector.

Definition at line 23 of file equirectangularprojector.cpp.

toScreenVec()

Eigen::Vector2f EquirectangularProjector::toScreenVec ( const SkyPoint * o, bool oRefract = true, bool * onVisibleHemisphere = nullptr ) const

overridevirtual

Given the coordinates of the SkyPoint argument, determine the pixel coordinates in the SkyMap.

Since most of the projections used by KStars are very similar, if this function were to be reimplemented in each projection subclass we would end up changing maybe 5 or 6 lines out of 150. Instead, we have a default implementation that uses the projectionK and projectionL functions to take care of the differences between e.g. Orthographic and Stereographic. There is also the cosMaxFieldAngle function, which is used for testing whether a point is on the visible part of the projection, and the radius function which gives the radius of the projection in screen coordinates.

While this seems ugly, it is less ugly than duplicating 150 loc to change 5.

Returns

Eigen::Vector2f containing screen pixel x, y coordinates of SkyPoint.

Parameters

o	pointer to the SkyPoint for which to calculate x, y coordinates.
oRefract	true = use Options::useRefraction() value. false = do not use refraction. This argument is only needed for the Horizon, which should never be refracted.
onVisibleHemisphere	pointer to a bool to indicate whether the point is on the visible part of the Celestial Sphere.

Reimplemented from Projector.

Definition at line 28 of file equirectangularprojector.cpp.

type()

Projector::Projection EquirectangularProjector::type ( ) const

overridevirtual

Return the type of this projection.

Implements Projector.

Definition at line 18 of file equirectangularprojector.cpp.

unusablePoint()

bool EquirectangularProjector::unusablePoint ( const QPointF & p ) const

overridevirtual

Check if the current point on screen is a valid point on the sky.

This is needed to avoid a crash of the program if the user clicks on a point outside the sky (the corners of the sky map at the lowest zoom level are the invalid points).

Parameters

p	the screen pixel position

Reimplemented from Projector.

Definition at line 97 of file equirectangularprojector.cpp.

updateClipPoly()

void EquirectangularProjector::updateClipPoly ( )

overridevirtual

updateClipPoly calculate the clipping polygen given the current FOV.

Reimplemented from Projector.

Definition at line 251 of file equirectangularprojector.cpp.

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

• equirectangularprojector.h
• equirectangularprojector.cpp