AbstractProjection.h

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//
// 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 2007-2008 Inge Wallin  <ingwa@kde.org>
// Copyright 2007-2012 Torsten Rahn  <rahn@kde.org>
//


#ifndef MARBLE_ABSTRACTPROJECTION_H
#define MARBLE_ABSTRACTPROJECTION_H


#include <QRect>
#include <QVector>
#include <QPainterPath>
#include <QPolygonF>

#include "GeoDataLatLonAltBox.h"
#include "GeoDataCoordinates.h"
#include "marble_export.h"

namespace Marble
{

// The manhattan distance in pixels at which extra nodes get created for tessellation.
static const int tessellationPrecision = 10;
static const int latLonAltBoxSamplingRate = 4;

class GeoDataLineString;
class ViewportParams;
class AbstractProjectionPrivate;


class MARBLE_EXPORT AbstractProjection
{
    // Not a QObject so far because we don't need to send signals.
 public:
    enum SurfaceType {
        Cylindrical,
        Pseudocylindrical,
        Hybrid,
        Conical,
        Pseudoconical,
        Azimuthal
    };

    enum PreservationType {
        NoPreservation,
        Conformal,
        EqualArea
    };

    AbstractProjection();

    virtual ~AbstractProjection();

    virtual qreal  maxValidLat() const;

    qreal  maxLat()  const;
    void setMaxLat( qreal maxLat );

    virtual qreal  minValidLat() const;

    qreal  minLat()  const;
    void setMinLat( qreal minLat );

    virtual bool   repeatableX() const              { return false; }
    virtual bool   traversablePoles()  const        { return false; }
    virtual bool   traversableDateLine()  const     { return false; }

    virtual SurfaceType surfaceType() const = 0; 

    virtual PreservationType preservationType() const { return NoPreservation; }

    // The projection surface can have different orientations:
    // - normal: the surface's axis of symmetry matches the Earth's axis
    // - transverse: orthogonally oriented compared to the Earth's axis
    // - oblique: somewhere in between

    virtual bool   isOrientedNormal() const        { return true; }

    bool screenCoordinates( const qreal lon, const qreal lat,
                            const ViewportParams *viewport,
                            qreal& x, qreal& y ) const;

    virtual bool screenCoordinates( const GeoDataCoordinates &geopoint, 
                                    const ViewportParams *viewport,
                                    qreal &x, qreal &y, 
                                    bool &globeHidesPoint ) const = 0;

    // Will just call the virtual version with a dummy globeHidesPoint.
    bool screenCoordinates( const GeoDataCoordinates &geopoint, 
                            const ViewportParams *viewport,
                            qreal &x, qreal &y ) const;

    virtual bool screenCoordinates( const GeoDataCoordinates &coordinates,
                                    const ViewportParams *viewport,
                                    qreal *x, qreal &y, int &pointRepeatNum,
                                    const QSizeF& size,
                                    bool &globeHidesPoint ) const = 0;

    virtual bool screenCoordinates( const GeoDataLineString &lineString,
                            const ViewportParams *viewport,
                            QVector<QPolygonF*> &polygons ) const = 0;

    virtual bool geoCoordinates( const int x, const int y,
                                 const ViewportParams *viewport,
                                 qreal& lon, qreal& lat,
                                 GeoDataCoordinates::Unit unit = GeoDataCoordinates::Degree ) const = 0;


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

    virtual bool mapCoversViewport( const ViewportParams *viewport ) const = 0;

    virtual QPainterPath mapShape( const ViewportParams *viewport ) const = 0;

    QRegion mapRegion( const ViewportParams *viewport ) const;

 protected:
     const QScopedPointer<AbstractProjectionPrivate> d_ptr;
     AbstractProjection( AbstractProjectionPrivate* dd );

 private:
     Q_DECLARE_PRIVATE(AbstractProjection)
     Q_DISABLE_COPY( AbstractProjection )
};

}

#endif