Marble

GeoDataLinearRing.h
1// SPDX-License-Identifier: LGPL-2.1-or-later
2//
3// SPDX-FileCopyrightText: 2008 Torsten Rahn <tackat@kde.org>
4//
5
6
7#ifndef MARBLE_GEODATALINEARRING_H
8#define MARBLE_GEODATALINEARRING_H
9
10
11#include "geodata_export.h"
12#include "GeoDataLineString.h"
13
14
15namespace Marble
16{
17
18class GeoDataLinearRingPrivate;
19
20/*!
21 \class GeoDataLinearRing
22 \brief A LinearRing that allows to store a closed, contiguous set of line segments.
23
24 GeoDataLinearRing is a tool class that implements the LinearRing tag/class
25 of the Open Geospatial Consortium standard KML 2.2.
26
27 Unlike suggested in the KML spec GeoDataLinearRing extends GeoDataLineString
28 to store a closed LineString (the KML specification suggests to inherit from
29 the Geometry class directly).
30
31 In the QPainter API LinearRings are also referred to as "polygons".
32 As such they are similar to QPolygons.
33
34 Whenever a LinearRing is painted GeoDataLineStyle should be used to assign a
35 color and line width.
36
37 A GeoDataLinearRing consists of several (geodetic) nodes which are each
38 connected through line segments. The nodes are stored as GeoDataCoordinates
39 objects.
40
41 The API which provides access to the nodes is similar to the API of
42 QVector.
43
44 GeoDataLinearRing allows LinearRings to be tessellated in order to make them
45 follow the terrain and the curvature of the earth. The tessellation options
46 allow for different ways of visualization:
47
48 \li Not tessellated: A LinearRing that connects each two nodes directly and
49 straight in screen coordinate space.
50 \li A tessellated line: Each line segment is bent so that the LinearRing
51 follows the curvature of the earth and its terrain. A tessellated
52 line segment connects two nodes at the shortest possible distance
53 ("along great circles").
54 \li A tessellated line that follows latitude circles whenever possible:
55 In this case Latitude circles are followed as soon as two subsequent
56 nodes have exactly the same amount of latitude. In all other places the
57 line segments follow great circles.
58
59 Some convenience methods have been added that allow to calculate the
60 geodesic bounding box or the length of a LinearRing.
61*/
62class GEODATA_EXPORT GeoDataLinearRing : public GeoDataLineString
63{
64
65 public:
66/*!
67 \brief Creates a new LinearRing.
68*/
69 explicit GeoDataLinearRing( TessellationFlags f = NoTessellation);
70
71
72/*!
73 \brief Creates a LinearRing from an existing geometry object.
74*/
75 explicit GeoDataLinearRing(const GeoDataGeometry &other);
76
77
78/*!
79 \brief Destroys a LinearRing.
80*/
81 ~GeoDataLinearRing() override;
82
83 const char *nodeType() const override;
84
85 EnumGeometryId geometryId() const override;
86
87 GeoDataGeometry *copy() const override;
88
89
90/*!
91 \brief Returns true/false depending on whether this and other are/are not equal.
92*/
93
94 bool operator==( const GeoDataLinearRing &other ) const;
95 bool operator!=( const GeoDataLinearRing &other ) const;
96
97
98/*!
99 \brief Returns whether a LinearRing is a closed polygon.
100
101 \return <code>true</code> for a LinearRing.
102*/
103 bool isClosed() const override;
104
105
106/*!
107 \brief Returns the length of the LinearRing across a sphere.
108
109 As a parameter the \a planetRadius needs to be passed.
110
111 \return The return value is the length of the LinearRing.
112 The unit used for the resulting length matches the unit of the planet
113 radius.
114
115 This method can be used as an approximation for the circumference of a
116 LinearRing.
117*/
118 qreal length( qreal planetRadius, int offset = 0 ) const override;
119
120/*!
121 \brief Returns whether the given coordinates lie within the polygon.
122
123 \return <code>true</code> if the coordinates lie within the polygon, false otherwise.
124*/
125 virtual bool contains( const GeoDataCoordinates &coordinates ) const;
126
127/*!
128 * \brief Returns whether the orientaion of ring is coloskwise or not
129 * \return Return value is true if ring is clockwise orientated
130 */
131 virtual bool isClockwise() const;
132};
133
134}
135
136#endif
A 3d point representation.
A base class for all geodata features.
A LineString that allows to store a contiguous set of line segments.
A LinearRing that allows to store a closed, contiguous set of line segments.
Binds a QML item to a specific geodetic location in screen coordinates.
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