StackedTileLoader.h

/*
    SPDX-FileCopyrightText: 2005-2007 Torsten Rahn <tackat@kde.org>
    SPDX-FileCopyrightText: 2007 Inge Wallin <ingwa@kde.org>
    SPDX-FileCopyrightText: 2009 Jens-Michael Hoffmann <jensmh@gmx.de>
    SPDX-FileCopyrightText: 2010-2012 Bernhard Beschow <bbeschow@cs.tu-berlin.de>
 
    SPDX-License-Identifier: LGPL-2.0-or-later
*/
 
#ifndef MARBLE_STACKEDTILELOADER_H
#define MARBLE_STACKEDTILELOADER_H
 
#include <QObject>
 
#include "RenderState.h"
 
class QImage;
class QString;
class QSize;
 
namespace Marble
{
 
class GeoSceneAbstractTileProjection;
class MergedLayerDecorator;
class StackedTile;
class TileId;
 
class StackedTileLoaderPrivate;
 
/**
 * @short Tile loading from a quad tree
 *
 * This class loads tiles into memory. For faster access
 * we keep the tileIDs and their respective pointers to
 * the tiles in a hashtable.
 * The class also contains convenience methods to remove entries
 * from the hashtable and to return more detailed properties
 * about each tile level and their tiles.
 *
 * @author Torsten Rahn <rahn@kde.org>
 **/
 
class StackedTileLoader : public QObject
{
    Q_OBJECT
 
public:
    /**
     * Creates a new tile loader.
     *
     * @param mergedLayerDecorator The decorator that shall be used to decorate
     *                        the layer.
     * @param parent The parent widget.
     */
    explicit StackedTileLoader(MergedLayerDecorator *mergedLayerDecorator, QObject *parent = nullptr);
    ~StackedTileLoader() override;
 
    int tileColumnCount(int level) const;
 
    int tileRowCount(int level) const;
 
    const GeoSceneAbstractTileProjection *tileProjection() const;
 
    QSize tileSize() const;
 
    /**
     * Loads a tile and returns it.
     *
     * @param stackedTileId The Id of the requested tile, containing the x and y coordinate
     *                      and the zoom level.
     */
    const StackedTile *loadTile(TileId const &stackedTileId);
 
    /**
     * Resets the internal tile hash.
     */
    void resetTilehash();
 
    /**
     * Cleans up the internal tile hash.
     *
     * Removes all superfluous tiles from the hash.
     */
    void cleanupTilehash();
 
    /**
     * @brief  Returns the limit of the volatile (in RAM) cache.
     * @return the cache limit in kilobytes
     */
    quint64 volatileCacheLimit() const;
 
    /**
     * @brief Reloads the tiles that are currently displayed.
     */
    QList<TileId> visibleTiles() const;
 
    /**
     * @brief Return the number of tiles in the cache.
     * @return number of tiles in cache
     */
    int tileCount() const;
 
    /**
     * @brief Set the limit of the volatile (in RAM) cache.
     * @param kiloBytes The limit in kilobytes.
     */
    void setVolatileCacheLimit(quint64 kiloBytes);
 
    /**
     * Effectively triggers a reload of all tiles that are currently in use
     * and clears the tile cache in physical memory.
     */
    void clear();
 
    /**
     */
    void updateTile(TileId const &tileId, QImage const &tileImage);
 
    RenderState renderState() const;
 
Q_SIGNALS:
    void tileLoaded(TileId const &tileId);
    void cleared();
 
private:
    Q_DISABLE_COPY(StackedTileLoader)
 
    friend class StackedTileLoaderPrivate;
    StackedTileLoaderPrivate *const d;
};
 
}
 
#endif