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/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the QtLocation module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this
** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of this
** file. Please review the following information to ensure the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qdeclarativecoordinate_p.h"
#include <qnumeric.h>
#include <QtQml/qqml.h>
QT_BEGIN_NAMESPACE
/*!
\qmlclass Coordinate QDeclarativeCoordinate
\inqmlmodule QtLocation 5
\ingroup qml-QtLocation5-positioning
\since Qt Location 5.0
\brief The Coordinate element represents and stores a geographic position.
Coordinate elements represent a geographic location in the form of numbers:
in particular, \l latitude, \l longitude and \l altitude. These, together,
specify a 3-dimensional position anywhere on or near the Earth's surface.
Coordinates are used by many other elements in the Qt Location module, for
specifying the position of an object on a Map, the current position of
a device and many other tasks. They also feature a number of important
utility methods that make otherwise complex calculations simple to use,
such as atDistanceAndAzimuth.
\section2 Accuracy
The latitude, longitude and altitude numbers stored in a Coordinate are
represented as doubles, giving them approximately 16 decimal digits of
precision -- enough to specify micrometers. The calculations performed
in Coordinate's methods such as azimuthTo and distanceTo also use doubles
for all intermediate values, but the inherent inaccuracies in their
spherical Earth model dominate the amount of error in their output.
\section2 Example Usage
The following snippet defines two coordinates near Brisbane, Australia.
\code
Coordinate {
id: coord1
latitude: -27.2
longitude: 153.1
altitude: 1.0
}
Coordinate {
id: coord2
latitude: -27.5
longitude: 153.2
altitude: 5.0
}
\endcode
As an example, the value of \c{coord1.distanceTo(coord2)} would now be
approximately 34790 (34.8 km).
\b{NOTE:} if another element has a Coordinate property, a change notification
signal for that property will only be emitted if that property is assigned
a new Coordinate, and \b{not} if the position data of the existing Coordinate
assigned to the property changes. The only exception to this rule is that
the \l{QDeclarativePosition}{Position} element does emit change signals if
its coordinate property's values change.
*/
QDeclarativeCoordinate::QDeclarativeCoordinate(QObject* parent)
: QObject(parent) {}
QDeclarativeCoordinate::QDeclarativeCoordinate(const QGeoCoordinate &coordinate,
QObject *parent)
: QObject(parent),
m_coordinate(coordinate) {}
QDeclarativeCoordinate::~QDeclarativeCoordinate() {}
/*!
\qmlproperty QGeoCoordinate Coordinate::coordinate
For details on how to use this property to interface between C++ and QML see
"\l {location-cpp-qml.html#geocoordinate} {Interfaces between C++ and QML Code}".
*/
void QDeclarativeCoordinate::setCoordinate(const QGeoCoordinate &coordinate)
{
bool changed = false;
QGeoCoordinate previousCoordinate = m_coordinate;
m_coordinate = coordinate;
// Comparing two NotANumbers is false which is not wanted here
if (coordinate.altitude() != previousCoordinate.altitude() &&
!(qIsNaN(coordinate.altitude()) && qIsNaN(previousCoordinate.altitude()))) {
emit altitudeChanged(m_coordinate.altitude());
changed = true;
}
if (coordinate.latitude() != previousCoordinate.latitude() &&
!(qIsNaN(coordinate.latitude()) && qIsNaN(previousCoordinate.latitude()))) {
emit latitudeChanged(m_coordinate.latitude());
changed = true;
}
if (coordinate.longitude() != previousCoordinate.longitude() &&
!(qIsNaN(coordinate.longitude()) && qIsNaN(previousCoordinate.longitude()))) {
emit longitudeChanged(m_coordinate.longitude());
changed = true;
}
if (changed)
emit coordinateChanged(m_coordinate);
}
QGeoCoordinate QDeclarativeCoordinate::coordinate() const
{
return m_coordinate;
}
/*!
\qmlproperty double Coordinate::altitude
This property holds the value of altitude (meters above sea level).
If the property has not been set, its default value is zero.
*/
void QDeclarativeCoordinate::setAltitude(double altitude)
{
bool wasValid = m_coordinate.isValid();
if (m_coordinate.altitude() != altitude) {
m_coordinate.setAltitude(altitude);
emit altitudeChanged(m_coordinate.altitude());
emit coordinateChanged(m_coordinate);
if (wasValid != m_coordinate.isValid())
emit validityChanged(m_coordinate.isValid());
}
}
double QDeclarativeCoordinate::altitude() const
{
return m_coordinate.altitude();
}
/*!
\qmlproperty double Coordinate::longitude
This property holds the longitude value of the geographical position
(decimal degrees). A positive longitude indicates the Eastern Hemisphere,
and a negative longitude indicates the Western Hemisphere
If the property has not been set, its default value is zero.
*/
void QDeclarativeCoordinate::setLongitude(double longitude)
{
bool wasValid = m_coordinate.isValid();
if (m_coordinate.longitude() != longitude) {
m_coordinate.setLongitude(longitude);
emit longitudeChanged(m_coordinate.longitude());
emit coordinateChanged(m_coordinate);
if (wasValid != m_coordinate.isValid())
emit validityChanged(m_coordinate.isValid());
}
}
double QDeclarativeCoordinate::longitude() const
{
return m_coordinate.longitude();
}
/*!
\qmlproperty double Coordinate::latitude
This property holds latitude value of the geographical position
(decimal degrees). A positive latitude indicates the Northern Hemisphere,
and a negative latitude indicates the Southern Hemisphere.
If the property has not been set, its default value is zero.
*/
void QDeclarativeCoordinate::setLatitude(double latitude)
{
bool wasValid = m_coordinate.isValid();
if (m_coordinate.latitude() != latitude) {
m_coordinate.setLatitude(latitude);
emit latitudeChanged(latitude);
emit coordinateChanged(m_coordinate);
if (wasValid != m_coordinate.isValid())
emit validityChanged(m_coordinate.isValid());
}
}
double QDeclarativeCoordinate::latitude() const
{
return m_coordinate.latitude();
}
/*!
\qmlproperty bool Coordinate::isValid
This property holds the current validity of the coordinate. Coordinates
are considered valid if they have been set with a valid latitude and
longitude (altitude is not required).
The latitude must be between -90 to 90 inclusive to be considered valid,
and the longitude must be between -180 to 180 inclusive to be considered
valid.
*/
bool QDeclarativeCoordinate::isValid() const
{
return m_coordinate.isValid();
}
/*!
\qmlmethod Coordinate::distanceTo(Coordinate)
Returns the distance (in meters) from this coordinate to the
coordinate specified by other. Altitude is not used in the calculation.
This calculation returns the great-circle distance between the two
coordinates, with an assumption that the Earth is spherical for the
purpose of this calculation.
*/
qreal QDeclarativeCoordinate::distanceTo(QObject* coordinate)
{
QDeclarativeCoordinate *coord = static_cast<QDeclarativeCoordinate*>(coordinate);
return m_coordinate.distanceTo(coord->coordinate());
}
/*!
\qmlmethod Coordinate::azimuthTo(Coordinate)
Returns the azimuth (or bearing) in degrees from this coordinate to the
coordinate specified by other. Altitude is not used in the calculation.
There is an assumption that the Earth is spherical for the purpose of
this calculation.
*/
qreal QDeclarativeCoordinate::azimuthTo(QObject *coordinate)
{
QDeclarativeCoordinate *coord = static_cast<QDeclarativeCoordinate*>(coordinate);
return m_coordinate.azimuthTo(coord->coordinate());
}
/*!
\qmlmethod Coordinate::atDistanceAndAzimuth(qreal, qreal)
Returns the coordinate that is reached by traveling distance metres
from the current coordinate at azimuth degrees along a great-circle.
There is an assumption that the Earth is spherical for the purpose
of this calculation.
*/
QDeclarativeCoordinate *QDeclarativeCoordinate::atDistanceAndAzimuth(qreal distance, qreal azimuth)
{
QGeoCoordinate coord = m_coordinate.atDistanceAndAzimuth(distance, azimuth);
return new QDeclarativeCoordinate(coord);
}
#include "moc_qdeclarativecoordinate_p.cpp"
QT_END_NAMESPACE
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