Marble

GnomonicProjection.cpp
1// SPDX-License-Identifier: LGPL-2.1-or-later
2//
3// SPDX-FileCopyrightText: 2013 Bernhard Beschow <bbeschow@cs.tu-berlin.de>
4//
5
6// Local
7#include "GnomonicProjection.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 GnomonicProjectionPrivate : public AzimuthalProjectionPrivate
29{
30 public:
31 explicit GnomonicProjectionPrivate( GnomonicProjection * parent );
32
33 Q_DECLARE_PUBLIC( GnomonicProjection )
34};
35
37 : AzimuthalProjection( new GnomonicProjectionPrivate( this ) )
38{
39 setMinLat( minValidLat() );
40 setMaxLat( maxValidLat() );
41}
42
43GnomonicProjection::GnomonicProjection( GnomonicProjectionPrivate *dd )
45{
46 setMinLat( minValidLat() );
47 setMaxLat( maxValidLat() );
48}
49
50GnomonicProjection::~GnomonicProjection()
51{
52}
53
54
55GnomonicProjectionPrivate::GnomonicProjectionPrivate( GnomonicProjection * parent )
56 : AzimuthalProjectionPrivate( parent )
57{
58}
59
61{
62 return QObject::tr( "Gnomonic" );
63}
64
66{
67 return QObject::tr( "<p><b>Gnomonic Projection</b> (\"rectilinear\")</p><p>Applications: Used for displaying panorama photography. Also used for navigation, radio and seismic work.</p>" );
68}
69
71{
72 return QIcon(QStringLiteral(":/icons/map-gnomonic.png"));
73}
74
75qreal GnomonicProjection::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
91 if ( cosC <= 0) {
92 globeHidesPoint = true;
93 return false;
94 }
95
96 // Let (x, y) be the position on the screen of the placemark..
97 x = ( qCos( phi ) * qSin( lambda - lambdaPrime ) ) / cosC;
98 y = ( qCos( phi1 ) * qSin( phi ) - qSin( phi1 ) * qCos( phi ) * qCos( lambda - lambdaPrime ) ) / cosC;
99
100 x *= viewport->radius() / 2;
101 y *= viewport->radius() / 2;
102
103 const qint64 radius = clippingRadius() * viewport->radius();
104
105 if (x*x + y*y > radius * radius) {
106 globeHidesPoint = true;
107 return false;
108 }
109
110 globeHidesPoint = false;
111
112 x += viewport->width() / 2;
113 y = viewport->height() / 2 - y;
114
115 // Skip placemarks that are outside the screen area
116 return !(x < 0 || x >= viewport->width() || y < 0 || y >= viewport->height());
117}
118
120 const ViewportParams *viewport,
121 qreal *x, qreal &y,
122 int &pointRepeatNum,
123 const QSizeF& size,
124 bool &globeHidesPoint ) const
125{
126 pointRepeatNum = 0;
127 globeHidesPoint = false;
128
129 bool visible = screenCoordinates( coordinates, viewport, *x, y, globeHidesPoint );
130
131 // Skip placemarks that are outside the screen area
132 if ( *x + size.width() / 2.0 < 0.0 || *x >= viewport->width() + size.width() / 2.0
133 || y + size.height() / 2.0 < 0.0 || y >= viewport->height() + size.height() / 2.0 )
134 {
135 return false;
136 }
137
138 // This projection doesn't have any repetitions,
139 // so the number of screen points referring to the geopoint is one.
140 pointRepeatNum = 1;
141 return visible;
142}
143
144
145bool GnomonicProjection::geoCoordinates( const int x, const int y,
146 const ViewportParams *viewport,
147 qreal& lon, qreal& lat,
148 GeoDataCoordinates::Unit unit ) const
149{
150 const qint64 radius = viewport->radius();
151 // Calculate how many degrees are being represented per pixel.
152 const qreal centerLon = viewport->centerLongitude();
153 const qreal centerLat = viewport->centerLatitude();
154 const qreal rx = ( - viewport->width() / 2 + x );
155 const qreal ry = ( viewport->height() / 2 - y );
156 const qreal p = qMax( qSqrt( rx*rx + ry*ry ), qreal(0.0001) ); // ensure we don't divide by zero
157 const qreal c = qAtan(2 * p / radius);
158 const qreal sinc = qSin(c);
159
160 lon = centerLon + qAtan2( rx*sinc , ( p*qCos( centerLat )*qCos( c ) - ry*qSin( centerLat )*sinc ) );
161
162 while ( lon < -M_PI ) lon += 2 * M_PI;
163 while ( lon > M_PI ) lon -= 2 * M_PI;
164
165 lat = qAsin( qCos(c)*qSin(centerLat) + ry*sinc*qCos(centerLat)/p );
166
167 if ( unit == GeoDataCoordinates::Degree ) {
168 lon *= RAD2DEG;
169 lat *= RAD2DEG;
170 }
171
172 return true;
173}
174
175}
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...
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.
QString name() const override
Returns the user-visible name of the projection.
GnomonicProjection()
Construct a new GnomonicProjection.
QString description() const override
Returns a short user description of the projection that can be used in tooltips or dialogs.
QIcon icon() const override
Returns an icon for the projection.
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
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