Marble

StereographicProjection.cpp
1// SPDX-License-Identifier: LGPL-2.1-or-later
2//
3// SPDX-FileCopyrightText: 2014 Torsten Rahn <rahn@kde.org>
4//
5
6// Local
7#include "StereographicProjection.h"
8#include "AbstractProjection_p.h"
9
10#include "MarbleDebug.h"
11
12// Marble
13#include "ViewportParams.h"
14#include "GeoDataPoint.h"
15#include "GeoDataLineString.h"
16#include "GeoDataCoordinates.h"
17#include "MarbleGlobal.h"
18#include "AzimuthalProjection_p.h"
19
20#include <QIcon>
21#include <qmath.h>
22
23#define SAFE_DISTANCE
24
25namespace Marble
26{
27
28class StereographicProjectionPrivate : public AzimuthalProjectionPrivate
29{
30 public:
31 explicit StereographicProjectionPrivate( StereographicProjection * parent );
32
33 Q_DECLARE_PUBLIC( StereographicProjection )
34};
35
37 : AzimuthalProjection( new StereographicProjectionPrivate( this ) )
38{
39 setMinLat( minValidLat() );
40 setMaxLat( maxValidLat() );
41}
42
43StereographicProjection::StereographicProjection( StereographicProjectionPrivate *dd )
45{
46 setMinLat( minValidLat() );
47 setMaxLat( maxValidLat() );
48}
49
50StereographicProjection::~StereographicProjection()
51{
52}
53
54
55StereographicProjectionPrivate::StereographicProjectionPrivate( StereographicProjection * parent )
56 : AzimuthalProjectionPrivate( parent )
57{
58}
59
61{
62 return QObject::tr( "Stereographic" );
63}
64
66{
67 return QObject::tr( "<p><b>Stereographic Projection</b> (\"orthogonal\")</p><p>Applications: Used for planetary cartography, geology and panorama photography.</p>" );
68}
69
71{
72 return QIcon(QStringLiteral(":/icons/map-globe.png"));
73}
74
75qreal StereographicProjection::clippingRadius() const
76{
77 return 1;
78}
79
81 const ViewportParams *viewport,
82 qreal &x, qreal &y, bool &globeHidesPoint ) const
83{
84 const qreal lambda = coordinates.longitude();
85 const qreal phi = coordinates.latitude();
86 const qreal lambdaPrime = viewport->centerLongitude();
87 const qreal phi1 = viewport->centerLatitude();
88
89 qreal cosC = qSin( phi1 ) * qSin( phi ) + qCos( phi1 ) * qCos( phi ) * qCos( lambda - lambdaPrime );
90 // Prevent division by zero
91 if (cosC <= 0) {
92 globeHidesPoint = true;
93 return false;
94 }
95
96 qreal k = 1 / (1 + cosC);
97
98 // Let (x, y) be the position on the screen of the placemark..
99 x = ( qCos( phi ) * qSin( lambda - lambdaPrime ) ) * k;
100 y = ( qCos( phi1 ) * qSin( phi ) - qSin( phi1 ) * qCos( phi ) * qCos( lambda - lambdaPrime ) ) * k;
101
102 x *= viewport->radius();
103 y *= viewport->radius();
104
105 const qint64 radius = clippingRadius() * viewport->radius();
106
107 if (x*x + y*y > radius * radius) {
108 globeHidesPoint = true;
109 return false;
110 }
111
112 globeHidesPoint = false;
113
114 x += viewport->width() / 2;
115 y = viewport->height() / 2 - y;
116
117 // Skip placemarks that are outside the screen area
118 return !(x < 0 || x >= viewport->width() || y < 0 || y >= viewport->height());
119}
120
122 const ViewportParams *viewport,
123 qreal *x, qreal &y,
124 int &pointRepeatNum,
125 const QSizeF& size,
126 bool &globeHidesPoint ) const
127{
128 pointRepeatNum = 0;
129 globeHidesPoint = false;
130
131 bool visible = screenCoordinates( coordinates, viewport, *x, y, globeHidesPoint );
132
133 // Skip placemarks that are outside the screen area
134 if ( *x + size.width() / 2.0 < 0.0 || *x >= viewport->width() + size.width() / 2.0
135 || y + size.height() / 2.0 < 0.0 || y >= viewport->height() + size.height() / 2.0 )
136 {
137 return false;
138 }
139
140 // This projection doesn't have any repetitions,
141 // so the number of screen points referring to the geopoint is one.
142 pointRepeatNum = 1;
143 return visible;
144}
145
146
147bool StereographicProjection::geoCoordinates( const int x, const int y,
148 const ViewportParams *viewport,
149 qreal& lon, qreal& lat,
150 GeoDataCoordinates::Unit unit ) const
151{
152 const qint64 radius = viewport->radius();
153 // Calculate how many degrees are being represented per pixel.
154 const qreal centerLon = viewport->centerLongitude();
155 const qreal centerLat = viewport->centerLatitude();
156 const qreal rx = ( - viewport->width() / 2 + x );
157 const qreal ry = ( viewport->height() / 2 - y );
158 const qreal p = qMax( qSqrt( rx*rx + ry*ry ), qreal(0.0001) ); // ensure we don't divide by zero
159 const qreal c = 2 * qAtan2( p , radius );
160 const qreal sinc = qSin(c);
161
162 lon = centerLon + qAtan2( rx*sinc , ( p*qCos( centerLat )*qCos( c ) - ry*qSin( centerLat )*sinc ) );
163
164 while ( lon < -M_PI ) lon += 2 * M_PI;
165 while ( lon > M_PI ) lon -= 2 * M_PI;
166
167 lat = qAsin( qCos(c)*qSin(centerLat) + (ry*sinc*qCos(centerLat))/p );
168
169 if ( unit == GeoDataCoordinates::Degree ) {
170 lon *= RAD2DEG;
171 lat *= RAD2DEG;
172 }
173
174 return true;
175}
176
177}
This file contains the headers for ViewportParams.
virtual qreal maxValidLat() const
Returns the maximum (northern) latitude that is mathematically defined and reasonable.
virtual qreal minValidLat() const
Returns the minimum (southern) latitude that is mathematically defined and reasonable.
A base class for the Gnomonic and Orthographic (Globe) projections in Marble.
A 3d point representation.
qreal longitude(GeoDataCoordinates::Unit unit) const
retrieves the longitude of the GeoDataCoordinates object use the unit parameter to switch between Rad...
Unit
enum used constructor to specify the units used
qreal latitude(GeoDataCoordinates::Unit unit) const
retrieves the latitude of the GeoDataCoordinates object use the unit parameter to switch between Radi...
QString name() const override
Returns the user-visible name of the projection.
StereographicProjection()
Construct a new StereographicProjection.
bool screenCoordinates(const GeoDataCoordinates &coordinates, const ViewportParams *params, qreal &x, qreal &y, bool &globeHidesPoint) const override
Get the screen coordinates corresponding to geographical coordinates in the map.
bool geoCoordinates(const int x, const int y, const ViewportParams *params, qreal &lon, qreal &lat, GeoDataCoordinates::Unit unit=GeoDataCoordinates::Degree) const override
Get the earth coordinates corresponding to a pixel in the map.
QIcon icon() const override
Returns an icon for the projection.
QString description() const override
Returns a short user description of the projection that can be used in tooltips or dialogs.
A public class that controls what is visible in the viewport of a Marble map.
Binds a QML item to a specific geodetic location in screen coordinates.
QString tr(const char *sourceText, const char *disambiguation, int n)
qreal height() const const
qreal width() const const
This file is part of the KDE documentation.
Documentation copyright © 1996-2024 The KDE developers.
Generated on Fri Jun 14 2024 11:54:17 by doxygen 1.10.0 written by Dimitri van Heesch, © 1997-2006

KDE's Doxygen guidelines are available online.