File indexing completed on 2025-01-05 03:59:33

 // SPDX-License-Identifier: LGPL-2.1-or-later
 //
 // SPDX-FileCopyrightText: 2014 Torsten Rahn <rahn@kde.org>
 //
 
 // Local
 #include "StereographicProjection.h"
 #include "AbstractProjection_p.h"
 
 #include <QIcon>
 #include <qmath.h>
 
 #include <klocalizedstring.h>
 
 // Marble
 #include "ViewportParams.h"
 #include "GeoDataPoint.h"
 #include "GeoDataLineString.h"
 #include "GeoDataCoordinates.h"
 #include "MarbleGlobal.h"
 #include "AzimuthalProjection_p.h"
 
 #include "digikam_debug.h"
 
 #define SAFE_DISTANCE
 
 namespace Marble
 {
 
 class StereographicProjectionPrivate : public AzimuthalProjectionPrivate
 {
   public:
     explicit StereographicProjectionPrivate( StereographicProjection * parent );
 
     Q_DECLARE_PUBLIC( StereographicProjection )
 };
 
 StereographicProjection::StereographicProjection()
     : AzimuthalProjection( new StereographicProjectionPrivate( this ) )
 {
     setMinLat( minValidLat() );
     setMaxLat( maxValidLat() );
 }
 
 StereographicProjection::StereographicProjection( StereographicProjectionPrivate *dd )
         : AzimuthalProjection( dd )
 {
     setMinLat( minValidLat() );
     setMaxLat( maxValidLat() );
 }
 
 StereographicProjection::~StereographicProjection()
 {
 }
 
 
 StereographicProjectionPrivate::StereographicProjectionPrivate( StereographicProjection * parent )
         : AzimuthalProjectionPrivate( parent )
 {
 }
 
 QString StereographicProjection::name() const
 {
     return i18n( "Stereographic" );
 }
 
 QString StereographicProjection::description() const
 {
     return i18n( "<p><b>Stereographic Projection</b> (\"orthogonal\")</p><p>Applications: Used for planetary cartography, geology and panorama photography.</p>" );
 }
 
 QIcon StereographicProjection::icon() const
 {
     return QIcon::fromTheme(QStringLiteral("map-globe"));
 }
 
 qreal StereographicProjection::clippingRadius() const
 {
     return 1;
 }
 
 bool StereographicProjection::screenCoordinates( const GeoDataCoordinates &coordinates,
                                              const ViewportParams *viewport,
                                              qreal &x, qreal &y, bool &globeHidesPoint ) const
 {
     const qreal lambda = coordinates.longitude();
     const qreal phi = coordinates.latitude();
     const qreal lambdaPrime = viewport->centerLongitude();
     const qreal phi1 = viewport->centerLatitude();
 
     qreal cosC = qSin( phi1 ) * qSin( phi ) + qCos( phi1 ) * qCos( phi ) * qCos( lambda - lambdaPrime );
     // Prevent division by zero
     if (cosC <= 0) {
         globeHidesPoint = true;
         return false;
     }
 
     qreal k = 1 / (1 + cosC);
 
     // Let (x, y) be the position on the screen of the placemark..
     x = ( qCos( phi ) * qSin( lambda - lambdaPrime ) ) * k;
     y = ( qCos( phi1 ) * qSin( phi ) - qSin( phi1 ) * qCos( phi ) * qCos( lambda - lambdaPrime ) ) * k;
 
     x *= viewport->radius();
     y *= viewport->radius();
 
     const qint64  radius  = clippingRadius() * viewport->radius();
 
     if (x*x + y*y > radius * radius) {
         globeHidesPoint = true;
         return false;
     }
 
     globeHidesPoint = false;
 
     x += viewport->width() / 2;
     y = viewport->height() / 2 - y;
 
     // Skip placemarks that are outside the screen area
     return !(x < 0 || x >= viewport->width() || y < 0 || y >= viewport->height());
 }
 
 bool StereographicProjection::screenCoordinates( const GeoDataCoordinates &coordinates,
                                              const ViewportParams *viewport,
                                              qreal *x, qreal &y,
                                              int &pointRepeatNum,
                                              const QSizeF& size,
                                              bool &globeHidesPoint ) const
 {
     pointRepeatNum = 0;
     globeHidesPoint = false;
 
     bool visible = screenCoordinates( coordinates, viewport, *x, y, globeHidesPoint );
 
     // Skip placemarks that are outside the screen area
     if ( *x + size.width() / 2.0 < 0.0 || *x >= viewport->width() + size.width() / 2.0
          || y + size.height() / 2.0 < 0.0 || y >= viewport->height() + size.height() / 2.0 )
     {
         return false;
     }
 
     // This projection doesn't have any repetitions,
     // so the number of screen points referring to the geopoint is one.
     pointRepeatNum = 1;
     return visible;
 }
 
 
 bool StereographicProjection::geoCoordinates( const int x, const int y,
                                           const ViewportParams *viewport,
                                           qreal& lon, qreal& lat,
                                           GeoDataCoordinates::Unit unit ) const
 {
     const qint64  radius  = viewport->radius();
     // Calculate how many degrees are being represented per pixel.
     const qreal centerLon = viewport->centerLongitude();
     const qreal centerLat = viewport->centerLatitude();
     const qreal rx = ( - viewport->width()  / 2 + x );
     const qreal ry = (   viewport->height() / 2 - y );
     const qreal p = qMax( qSqrt( rx*rx + ry*ry ), qreal(0.0001) ); // ensure we don't divide by zero
     const qreal c = 2 * qAtan2( p , radius );
     const qreal sinc = qSin(c);
 
     lon = centerLon + qAtan2( rx*sinc , ( p*qCos( centerLat )*qCos( c ) - ry*qSin( centerLat )*sinc  ) );
 
     while ( lon < -M_PI ) lon += 2 * M_PI;
     while ( lon >  M_PI ) lon -= 2 * M_PI;
 
     lat = qAsin( qCos(c)*qSin(centerLat) + (ry*sinc*qCos(centerLat))/p );
 
     if ( unit == GeoDataCoordinates::Degree ) {
         lon *= RAD2DEG;
         lat *= RAD2DEG;
     }
 
     return true;
 }
 
 }