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6** This file is part of the QtPositioning module of the Qt Toolkit.
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38****************************************************************************/
39#include "qwebmercator_p.h"
40
41#include "qgeocoordinate.h"
42
43#include <qnumeric.h>
44#include <qmath.h>
45
46#include "qdoublevector2d_p.h"
47#include "qdoublevector3d_p.h"
48
49QT_BEGIN_NAMESPACE
50
51QDoubleVector2D QWebMercator::coordToMercator(const QGeoCoordinate &coord)
52{
53 const double pi = M_PI;
54
55 double lon = coord.longitude() / 360.0 + 0.5;
56
57 double lat = coord.latitude();
58 lat = 0.5 - (std::log(x: std::tan(x: (pi / 4.0) + (pi / 2.0) * lat / 180.0)) / pi) / 2.0;
59 lat = qBound(min: 0.0, val: lat, max: 1.0);
60
61 return QDoubleVector2D(lon, lat);
62}
63
64double QWebMercator::realmod(const double a, const double b)
65{
66 quint64 div = static_cast<quint64>(a / b);
67 return a - static_cast<double>(div) * b;
68}
69
70QGeoCoordinate QWebMercator::mercatorToCoord(const QDoubleVector2D &mercator)
71{
72 const double pi = M_PI;
73
74 double fx = mercator.x();
75 double fy = mercator.y();
76
77 if (fy < 0.0)
78 fy = 0.0;
79 else if (fy > 1.0)
80 fy = 1.0;
81
82 double lat;
83
84 if (fy == 0.0)
85 lat = 90.0;
86 else if (fy == 1.0)
87 lat = -90.0;
88 else
89 lat = (180.0 / pi) * (2.0 * std::atan(x: std::exp(x: pi * (1.0 - 2.0 * fy))) - (pi / 2.0));
90
91 double lng;
92 if (fx >= 0) {
93 lng = realmod(a: fx, b: 1.0);
94 } else {
95 lng = realmod(a: 1.0 - realmod(a: -1.0 * fx, b: 1.0), b: 1.0);
96 }
97
98 lng = lng * 360.0 - 180.0;
99
100 return QGeoCoordinate(lat, lng, 0.0);
101}
102
103QGeoCoordinate QWebMercator::coordinateInterpolation(const QGeoCoordinate &from, const QGeoCoordinate &to, qreal progress)
104{
105 QDoubleVector2D s = QWebMercator::coordToMercator(coord: from);
106 QDoubleVector2D e = QWebMercator::coordToMercator(coord: to);
107
108 double x = s.x();
109
110 if (0.5 < qAbs(t: e.x() - s.x())) {
111 // handle dateline crossing
112 double ex = e.x();
113 double sx = s.x();
114 if (ex < sx)
115 sx -= 1.0;
116 else if (sx < ex)
117 ex -= 1.0;
118
119 x = (1.0 - progress) * sx + progress * ex;
120
121 if (!qFuzzyIsNull(d: x) && (x < 0.0))
122 x += 1.0;
123
124 } else {
125 x = (1.0 - progress) * s.x() + progress * e.x();
126 }
127
128 double y = (1.0 - progress) * s.y() + progress * e.y();
129
130 QGeoCoordinate result = QWebMercator::mercatorToCoord(mercator: QDoubleVector2D(x, y));
131 result.setAltitude((1.0 - progress) * from.altitude() + progress * to.altitude());
132
133 return result;
134}
135
136QT_END_NAMESPACE
137

source code of qtlocation/src/positioning/qwebmercator.cpp