//
// This file is part of the Marble Virtual Globe.
//
// This program is free software licensed under the GNU LGPL. You can
// find a copy of this license in LICENSE.txt in the top directory of
// the source code.
//
// Copyright 2007      Inge Wallin  <ingwa@kde.org>
// Copyright 2007-2012 Torsten Rahn  <rahn@kde.org>
//


#ifndef MARBLE_MERCATORPROJECTION_H
#define MARBLE_MERCATORPROJECTION_H


/** @file
 * This file contains the headers for MercatorProjection.
 *
 * @author Inge Wallin  <inge@lysator.liu.se>
 * @author Torsten Rahn <rahn@kde.org>
 */


#include "CylindricalProjection.h"

namespace Marble
{

/**
 * @short A class to implement the Mercator projection.
 */

class MercatorProjection : public CylindricalProjection
{
    // Not a QObject so far because we don't need to send signals.
 public:

    /**
     * @brief Construct a new MercatorProjection.
     */
    MercatorProjection();

    ~MercatorProjection() override;

    /**
     * @brief Returns the user-visible name of the projection.
     */
    QString name() const override;

    /**
     * @brief Returns a short user description of the projection
     * that can be used in tooltips or dialogs.
     */
    QString description() const override;

    /**
     * @brief Returns an icon for the projection.
     */
    QIcon icon() const override;

    qreal  maxValidLat() const override;
    qreal  minValidLat() const override;

    PreservationType preservationType() const override { return Conformal; }

    /**
     * @brief Get the screen coordinates corresponding to geographical coordinates in the map.
     * @param coordinates  the coordinates of the requested pixel position
     * @param params the viewport parameters
     * @param x      the x coordinate of the pixel is returned through this parameter
     * @param y      the y coordinate of the pixel is returned through this parameter
     * @param globeHidesPoint whether the globe hides the point
     * @return @c true  if the geographical coordinates are visible on the screen
     *         @c false if the geographical coordinates are not visible on the screen
     */
    bool screenCoordinates( const GeoDataCoordinates &coordinates, 
                            const ViewportParams *params,
                            qreal &x, qreal &y, bool &globeHidesPoint ) const override;

    bool screenCoordinates( const GeoDataCoordinates &coordinates,
                            const ViewportParams * viewport,
                            qreal *x, qreal &y, int &pointRepeatNum,
                            const QSizeF& size,
                            bool &globeHidesPoint ) const override;

    using CylindricalProjection::screenCoordinates;

   /**
     * @brief Get the earth coordinates corresponding to a pixel in the map.
     *
     * If the pixel (x, y) is outside the globe, only @p lon will be calculated,
     * and lat will be unchanged.
     *
     * @param x      the x coordinate of the pixel
     * @param y      the y coordinate of the pixel
     * @param params the viewport parameters
     * @param lon    the longitude angle is returned through this parameter
     * @param lat    the latitude angle is returned through this parameter
     * @param unit   the unit
     * @return @c true  if the pixel (x, y) is within the globe
     *         @c false if the pixel (x, y) is outside the globe, i.e. in space.
     */
    bool geoCoordinates( const int x, const int y,
                         const ViewportParams *params,
                         qreal& lon, qreal& lat,
                         GeoDataCoordinates::Unit = GeoDataCoordinates::Degree ) const override;

    GeoDataLatLonAltBox latLonAltBox( const QRect &screenRect,
                                      const ViewportParams *viewport ) const override;

    bool  mapCoversViewport( const ViewportParams *viewport ) const override;

 private:
    mutable qreal m_lastCenterLat;
    mutable qreal m_lastCenterLatInv;

    Q_DISABLE_COPY( MercatorProjection )
};

}

#endif
