ViewportParams.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      Inge Wallin  <ingwa@kde.org>
// Copyright 2008      Jens-Michael Hoffmann <jensmh@gmx.de>
//

#ifndef MARBLE_VIEWPORTPARAMS_H
#define MARBLE_VIEWPORTPARAMS_H


#include <QSize>
#include <QPainterPath>

#include "GeoDataLatLonAltBox.h"

#include "Quaternion.h"
#include "MarbleGlobal.h"
#include "marble_export.h"

class QPolygonF;

namespace Marble
{

class AbstractProjection;
class ViewportParamsPrivate;

class MARBLE_EXPORT ViewportParams
{
 public:
    ViewportParams( );
    explicit ViewportParams( Projection projection,
                             qreal centerLongitude = 0, qreal centerLatatitude = 0,
                             int radius = 2000,
                             const QSize &size = QSize( 100, 100 ) );
    ~ViewportParams();

    // Getters and setters
    Projection projection() const;
    const AbstractProjection *currentProjection() const;
    void setProjection(Projection newProjection);

    int polarity() const;

    const GeoDataLatLonAltBox& viewLatLonAltBox() const;

    GeoDataLatLonAltBox latLonAltBox( const QRect &screenRect ) const;

    // Calculates an educated guess for the average angle in radians covered per pixel.
    // Given a certain resolution it doesn't make much sense
    // - to display an object that covers an angle that is smaller than that.
    // - to display two points as distinct points if they are separated by a 
    //   an angular distance that is smaller. Instead only one point should be shown.
    // So this method helps to filter out details.
    // It's somewhat related to http://en.wikipedia.org/wiki/Angular_resolution

    qreal angularResolution() const;

    // Determines whether a geographical feature is big enough so that it should 
    // represent a single point on the screen already.
    // See angularResolution()

    bool resolves ( const GeoDataLatLonBox &latLonBox ) const;

    bool resolves ( const GeoDataLatLonAltBox &latLonAltBox ) const;

    // Determines whether two points are located enough apart so that it makes 
    // sense to display them as distinct points. If this is not the case
    // calculation and drawing of one point can be skipped as only a single
    // point will be displayed on the screen.
    
    bool resolves ( const GeoDataCoordinates &coord1, const GeoDataCoordinates &coord2 ) const;

    int  radius() const;

    void setRadius(int radius);

    void centerOn( qreal lon, qreal lat );

    Quaternion planetAxis() const;
    const matrix &planetAxisMatrix() const;

    int width()  const;
    int height() const;
    QSize size() const;

    void setWidth(int newWidth);
    void setHeight(int newHeight);
    void setSize(QSize newSize);

    qreal centerLongitude() const;
    qreal centerLatitude() const;
    MARBLE_DEPRECATED( void centerCoordinates( qreal &centerLon, qreal &centerLat ) const );

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

    bool screenCoordinates( const GeoDataCoordinates &geopoint,
                            qreal &x, qreal &y,
                            bool &globeHidesPoint ) const;

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

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


    bool screenCoordinates( const GeoDataLineString &lineString,
                            QVector<QPolygonF*> &polygons ) const;

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

    bool mapCoversViewport() const;

    QPainterPath mapShape() const;

    QRegion mapRegion() const;

    GeoDataCoordinates focusPoint() const;

    void setFocusPoint(const GeoDataCoordinates &focusPoint);

    void resetFocusPoint();

 private:
    Q_DISABLE_COPY( ViewportParams )
    ViewportParamsPrivate * const d;
};

}

#endif