qt-everywhere-src-5.15.1/qtlocation/src/location/maps/qgeotiledmap.cpp - orbit - Git at Google

 /****************************************************************************
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
 ** Contact: http://www.qt.io/licensing/
 **
 ** This file is part of the QtLocation module of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:LGPL3$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
 ** and conditions see http://www.qt.io/terms-conditions. For further
 ** information use the contact form at http://www.qt.io/contact-us.
 **
 ** GNU Lesser General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU Lesser
 ** General Public License version 3 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.LGPLv3 included in the
 ** packaging of this file. Please review the following information to
 ** ensure the GNU Lesser General Public License version 3 requirements
 ** will be met: https://www.gnu.org/licenses/lgpl.html.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 2.0 or later 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 2.0 requirements will be
 ** met: http://www.gnu.org/licenses/gpl-2.0.html.
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
 #include "qgeotiledmap_p.h"
 #include "qgeotiledmap_p_p.h"
 #include <QtPositioning/private/qwebmercator_p.h>
 #include "qgeotiledmappingmanagerengine_p.h"
 #include "qabstractgeotilecache_p.h"
 #include "qgeotilespec_p.h"
 #include "qgeoprojection_p.h"

 #include "qgeocameratiles_p.h"
 #include "qgeotilerequestmanager_p.h"
 #include "qgeotiledmapscene_p.h"
 #include "qgeocameracapabilities_p.h"
 #include <cmath>

 QT_BEGIN_NAMESPACE
 #define PREFETCH_FRUSTUM_SCALE 2.0

 static const double invLog2 = 1.0 / std::log(2.0);

 static double zoomLevelFrom256(double zoomLevelFor256, double tileSize)
 {
     return std::log( std::pow(2.0, zoomLevelFor256) * 256.0 / tileSize ) * invLog2;
 }

 QGeoTiledMap::QGeoTiledMap(QGeoTiledMappingManagerEngine *engine, QObject *parent)
     : QGeoMap(*new QGeoTiledMapPrivate(engine), parent)
 {
     Q_D(QGeoTiledMap);

     d->m_tileRequests = new QGeoTileRequestManager(this, engine);

     QObject::connect(engine,&QGeoTiledMappingManagerEngine::tileVersionChanged,
                      this,&QGeoTiledMap::handleTileVersionChanged);
     QObject::connect(this, &QGeoMap::cameraCapabilitiesChanged,
                      [d](const QGeoCameraCapabilities &oldCameraCapabilities) {
                        d->onCameraCapabilitiesChanged(oldCameraCapabilities);
                      });
 }

 QGeoTiledMap::QGeoTiledMap(QGeoTiledMapPrivate &dd, QGeoTiledMappingManagerEngine *engine, QObject *parent)
     : QGeoMap(dd, parent)
 {
     Q_D(QGeoTiledMap);

     d->m_tileRequests = new QGeoTileRequestManager(this, engine);

     QObject::connect(engine,&QGeoTiledMappingManagerEngine::tileVersionChanged,
                      this,&QGeoTiledMap::handleTileVersionChanged);
     QObject::connect(this, &QGeoMap::cameraCapabilitiesChanged,
                      [d](const QGeoCameraCapabilities &oldCameraCapabilities) {
                        d->onCameraCapabilitiesChanged(oldCameraCapabilities);
                      });
 }

 QGeoTiledMap::~QGeoTiledMap()
 {
     Q_D(QGeoTiledMap);
     delete d->m_tileRequests;
     d->m_tileRequests = 0;

     if (!d->m_engine.isNull()) {
         QGeoTiledMappingManagerEngine *engine = qobject_cast<QGeoTiledMappingManagerEngine*>(d->m_engine);
         Q_ASSERT(engine);
         engine->releaseMap(this);
     }
 }

 QGeoTileRequestManager *QGeoTiledMap::requestManager()
 {
     Q_D(QGeoTiledMap);
     return d->m_tileRequests;
 }

 void QGeoTiledMap::updateTile(const QGeoTileSpec &spec)
 {
     Q_D(QGeoTiledMap);
     d->updateTile(spec);
 }

 void QGeoTiledMap::setPrefetchStyle(QGeoTiledMap::PrefetchStyle style)
 {
     Q_D(QGeoTiledMap);
     d->m_prefetchStyle = style;
 }

 QAbstractGeoTileCache *QGeoTiledMap::tileCache()
 {
     Q_D(QGeoTiledMap);
     return d->m_cache;
 }

 QSGNode *QGeoTiledMap::updateSceneGraph(QSGNode *oldNode, QQuickWindow *window)
 {
     Q_D(QGeoTiledMap);
     return d->updateSceneGraph(oldNode, window);
 }

 void QGeoTiledMap::prefetchData()
 {
     Q_D(QGeoTiledMap);
     d->prefetchTiles();
 }

 void QGeoTiledMap::clearData()
 {
     Q_D(QGeoTiledMap);
     d->m_cache->clearAll();
     d->m_mapScene->clearTexturedTiles();
     d->updateScene();
     sgNodeChanged();
 }

 QGeoMap::Capabilities QGeoTiledMap::capabilities() const
 {
     return Capabilities(SupportsVisibleRegion
                         | SupportsSetBearing
                         | SupportsAnchoringCoordinate
                         | SupportsVisibleArea);
 }

 void QGeoTiledMap::setCopyrightVisible(bool visible)
 {
     Q_D(QGeoTiledMap);
     if (visible == d->m_copyrightVisible)
         return;

     QGeoMap::setCopyrightVisible(visible);
     if (visible)
         evaluateCopyrights(d->m_mapScene->visibleTiles());
 }

 void QGeoTiledMap::clearScene(int mapId)
 {
     Q_D(QGeoTiledMap);
     if (activeMapType().mapId() == mapId)
         d->clearScene();
 }

 void QGeoTiledMap::handleTileVersionChanged()
 {
     Q_D(QGeoTiledMap);
     if (!d->m_engine.isNull()) {
         QGeoTiledMappingManagerEngine* engine = qobject_cast<QGeoTiledMappingManagerEngine*>(d->m_engine);
         Q_ASSERT(engine);
         d->changeTileVersion(engine->tileVersion());
     }
 }

 void QGeoTiledMap::evaluateCopyrights(const QSet<QGeoTileSpec> &visibleTiles)
 {
     Q_UNUSED(visibleTiles);
 }

 QGeoTiledMapPrivate::QGeoTiledMapPrivate(QGeoTiledMappingManagerEngine *engine)
     : QGeoMapPrivate(engine, new QGeoProjectionWebMercator),
       m_cache(engine->tileCache()),
       m_visibleTiles(new QGeoCameraTiles()),
       m_prefetchTiles(new QGeoCameraTiles()),
       m_mapScene(new QGeoTiledMapScene()),
       m_tileRequests(0),
       m_maxZoomLevel(static_cast<int>(std::ceil(m_cameraCapabilities.maximumZoomLevel()))),
       m_minZoomLevel(static_cast<int>(std::ceil(m_cameraCapabilities.minimumZoomLevel()))),
       m_prefetchStyle(QGeoTiledMap::PrefetchTwoNeighbourLayers)
 {
     int tileSize = m_cameraCapabilities.tileSize();
     QString pluginString(engine->managerName() + QLatin1Char('_') + QString::number(engine->managerVersion()));
     m_visibleTiles->setTileSize(tileSize);
     m_prefetchTiles->setTileSize(tileSize);
     m_visibleTiles->setPluginString(pluginString);
     m_prefetchTiles->setPluginString(pluginString);
     m_mapScene->setTileSize(tileSize);
 }

 QGeoTiledMapPrivate::~QGeoTiledMapPrivate()
 {
     // controller_ is a child of map_, don't need to delete it here

     delete m_mapScene;
     delete m_visibleTiles;
     delete m_prefetchTiles;

     // TODO map items are not deallocated!
     // However: how to ensure this is done in rendering thread?
 }

 void QGeoTiledMapPrivate::prefetchTiles()
 {
     if (m_tileRequests && m_prefetchStyle != QGeoTiledMap::NoPrefetching) {

         QSet<QGeoTileSpec> tiles;
         QGeoCameraData camera = m_visibleTiles->cameraData();
         int currentIntZoom = static_cast<int>(std::floor(camera.zoomLevel()));

         m_prefetchTiles->setCameraData(camera);
         m_prefetchTiles->setViewExpansion(PREFETCH_FRUSTUM_SCALE);
         tiles = m_prefetchTiles->createTiles();

         switch (m_prefetchStyle) {

         case QGeoTiledMap::PrefetchNeighbourLayer: {
             double zoomFraction = camera.zoomLevel() - currentIntZoom;
             int nearestNeighbourLayer = zoomFraction > 0.5 ? currentIntZoom + 1 : currentIntZoom - 1;
             if (nearestNeighbourLayer <= m_maxZoomLevel && nearestNeighbourLayer >= m_minZoomLevel) {
                 camera.setZoomLevel(nearestNeighbourLayer);
                 // Approx heuristic, keeping total # prefetched tiles roughly independent of the
                 // fractional zoom level.
                 double neighbourScale = (1.0 + zoomFraction)/2.0;
                 m_prefetchTiles->setCameraData(camera);
                 m_prefetchTiles->setViewExpansion(PREFETCH_FRUSTUM_SCALE * neighbourScale);
                 tiles += m_prefetchTiles->createTiles();
             }
         }
             break;

         case QGeoTiledMap::PrefetchTwoNeighbourLayers: {
             // This is a simpler strategy, we just prefetch from layer above and below
             // for the layer below we only use half the size as this fills the screen
             if (currentIntZoom > m_minZoomLevel) {
                 camera.setZoomLevel(currentIntZoom - 1);
                 m_prefetchTiles->setCameraData(camera);
                 m_prefetchTiles->setViewExpansion(0.5);
                 tiles += m_prefetchTiles->createTiles();
             }

             if (currentIntZoom < m_maxZoomLevel) {
                 camera.setZoomLevel(currentIntZoom + 1);
                 m_prefetchTiles->setCameraData(camera);
                 m_prefetchTiles->setViewExpansion(1.0);
                 tiles += m_prefetchTiles->createTiles();
             }
         }
             break;

         default:
             break;
         }

         m_tileRequests->requestTiles(tiles - m_mapScene->texturedTiles());
     }
 }

 QGeoMapType QGeoTiledMapPrivate::activeMapType()
 {
     return m_visibleTiles->activeMapType();
 }

 // Called before changeCameraData
 void QGeoTiledMapPrivate::onCameraCapabilitiesChanged(const QGeoCameraCapabilities &oldCameraCapabilities)
 {
     // Handle varying min/maxZoomLevel
     if (oldCameraCapabilities.minimumZoomLevel() != m_cameraCapabilities.minimumZoomLevel())
         m_minZoomLevel = static_cast<int>(std::ceil(m_cameraCapabilities.minimumZoomLevel()));
     if (oldCameraCapabilities.maximumZoomLevel() != m_cameraCapabilities.maximumZoomLevel())
         m_maxZoomLevel = static_cast<int>(std::ceil(m_cameraCapabilities.maximumZoomLevel()));

     // Handle varying tile size
     if (oldCameraCapabilities.tileSize() != m_cameraCapabilities.tileSize()) {
         m_visibleTiles->setTileSize(oldCameraCapabilities.tileSize());
         m_prefetchTiles->setTileSize(oldCameraCapabilities.tileSize());
         m_mapScene->setTileSize(oldCameraCapabilities.tileSize());
     }
 }

 void QGeoTiledMapPrivate::changeCameraData(const QGeoCameraData &cameraData)
 {
     Q_Q(QGeoTiledMap);

     QGeoCameraData cam = cameraData;

     // The incoming zoom level is intended for a tileSize of 256.
     // Adapt it to the current tileSize
     double zoomLevel = cameraData.zoomLevel();
     if (m_visibleTiles->tileSize() != 256)
         zoomLevel = zoomLevelFrom256(zoomLevel, m_visibleTiles->tileSize());
     cam.setZoomLevel(zoomLevel);

     // For zoomlevel, "snap" 0.01 either side of a whole number.
     // This is so that when we turn off bilinear scaling, we're
     // snapped to the exact pixel size of the tiles
     int izl = static_cast<int>(std::floor(cam.zoomLevel()));
     float delta = cam.zoomLevel() - izl;

     if (delta > 0.5) {
         izl++;
         delta -= 1.0;
     }

     // TODO: Don't do this if there's tilt or bearing.
     if (qAbs(delta) < 0.01) {
         cam.setZoomLevel(izl);
     }

     m_visibleTiles->setCameraData(cam);
     m_mapScene->setCameraData(cam);

     updateScene();
     q->sgNodeChanged(); // ToDo: explain why emitting twice
 }

 void QGeoTiledMapPrivate::updateScene()
 {
     Q_Q(QGeoTiledMap);
     // detect if new tiles introduced
     const QSet<QGeoTileSpec>& tiles = m_visibleTiles->createTiles();
     bool newTilesIntroduced = !m_mapScene->visibleTiles().contains(tiles);
     m_mapScene->setVisibleTiles(tiles);

     if (newTilesIntroduced && m_copyrightVisible)
         q->evaluateCopyrights(tiles);

     // don't request tiles that are already built and textured
     QMap<QGeoTileSpec, QSharedPointer<QGeoTileTexture> > cachedTiles =
             m_tileRequests->requestTiles(m_visibleTiles->createTiles() - m_mapScene->texturedTiles());

     for (auto it = cachedTiles.cbegin(); it != cachedTiles.cend(); ++it)
         m_mapScene->addTile(it.key(), it.value());

     if (!cachedTiles.isEmpty())
         emit q->sgNodeChanged();
 }

 void QGeoTiledMapPrivate::setVisibleArea(const QRectF &visibleArea)
 {
     Q_Q(QGeoTiledMap);
     const QRectF va = clampVisibleArea(visibleArea);
     if (va == m_visibleArea)
         return;

     m_visibleArea = va;
     m_geoProjection->setVisibleArea(va);

     m_visibleTiles->setVisibleArea(va);
     m_prefetchTiles->setVisibleArea(va);
     m_mapScene->setVisibleArea(va);

      if (m_copyrightVisible)
         q->evaluateCopyrights(m_mapScene->visibleTiles());
     updateScene();
     q->sgNodeChanged(); // ToDo: explain why emitting twice
 }

 QRectF QGeoTiledMapPrivate::visibleArea() const
 {
     return m_visibleArea;
 }

 void QGeoTiledMapPrivate::changeActiveMapType(const QGeoMapType mapType)
 {
     m_visibleTiles->setTileSize(m_cameraCapabilities.tileSize());
     m_prefetchTiles->setTileSize(m_cameraCapabilities.tileSize());
     m_mapScene->setTileSize(m_cameraCapabilities.tileSize());
     m_visibleTiles->setMapType(mapType);
     m_prefetchTiles->setMapType(mapType);
     changeCameraData(m_cameraData); // Updates the zoom level to the possibly new tile size
     // updateScene called in changeCameraData()
 }

 void QGeoTiledMapPrivate::changeTileVersion(int version)
 {
     m_visibleTiles->setMapVersion(version);
     m_prefetchTiles->setMapVersion(version);
     updateScene();
 }

 void QGeoTiledMapPrivate::clearScene()
 {
     m_mapScene->clearTexturedTiles();
     m_mapScene->setVisibleTiles(QSet<QGeoTileSpec>());
     updateScene();
 }

 void QGeoTiledMapPrivate::changeViewportSize(const QSize& size)
 {
     Q_Q(QGeoTiledMap);

     m_visibleTiles->setScreenSize(size);
     m_prefetchTiles->setScreenSize(size);
     m_mapScene->setScreenSize(size);


     if (!size.isEmpty() && m_cache) {
         // absolute minimum size: one tile each side of display, 32-bit colour
         int texCacheSize = (size.width() + m_visibleTiles->tileSize() * 2) *
                 (size.height() + m_visibleTiles->tileSize() * 2) * 4;

         // multiply by 3 so the 'recent' list in the cache is big enough for
         // an entire display of tiles
         texCacheSize *= 3;
         // TODO: move this reasoning into the tilecache

         int newSize = qMax(m_cache->minTextureUsage(), texCacheSize);
         m_cache->setMinTextureUsage(newSize);
     }

     if (m_copyrightVisible)
         q->evaluateCopyrights(m_mapScene->visibleTiles());
     updateScene();
 }

 void QGeoTiledMapPrivate::updateTile(const QGeoTileSpec &spec)
 {
      Q_Q(QGeoTiledMap);
     // Only promote the texture up to GPU if it is visible
     if (m_visibleTiles->createTiles().contains(spec)){
         QSharedPointer<QGeoTileTexture> tex = m_tileRequests->tileTexture(spec);
         if (!tex.isNull() && !tex->image.isNull()) {
             m_mapScene->addTile(spec, tex);
             emit q->sgNodeChanged();
         }
     }
 }

 QSGNode *QGeoTiledMapPrivate::updateSceneGraph(QSGNode *oldNode, QQuickWindow *window)
 {
     return m_mapScene->updateSceneGraph(oldNode, window);
 }

 QT_END_NAMESPACE
	/****************************************************************************
	**
	** Copyright (C) 2015 The Qt Company Ltd.
	** Contact: http://www.qt.io/licensing/
	**
	** This file is part of the QtLocation module of the Qt Toolkit.
	**
	** $QT_BEGIN_LICENSE:LGPL3$
	** Commercial License Usage
	** Licensees holding valid commercial Qt licenses may use this file in
	** accordance with the commercial license agreement provided with the
	** Software or, alternatively, in accordance with the terms contained in
	** a written agreement between you and The Qt Company. For licensing terms
	** and conditions see http://www.qt.io/terms-conditions. For further
	** information use the contact form at http://www.qt.io/contact-us.
	**
	** GNU Lesser General Public License Usage
	** Alternatively, this file may be used under the terms of the GNU Lesser
	** General Public License version 3 as published by the Free Software
	** Foundation and appearing in the file LICENSE.LGPLv3 included in the
	** packaging of this file. Please review the following information to
	** ensure the GNU Lesser General Public License version 3 requirements
	** will be met: https://www.gnu.org/licenses/lgpl.html.
	**
	** GNU General Public License Usage
	** Alternatively, this file may be used under the terms of the GNU
	** General Public License version 2.0 or later 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 2.0 requirements will be
	** met: http://www.gnu.org/licenses/gpl-2.0.html.
	**
	** $QT_END_LICENSE$
	**
	****************************************************************************/
	#include "qgeotiledmap_p.h"
	#include "qgeotiledmap_p_p.h"
	#include <QtPositioning/private/qwebmercator_p.h>
	#include "qgeotiledmappingmanagerengine_p.h"
	#include "qabstractgeotilecache_p.h"
	#include "qgeotilespec_p.h"
	#include "qgeoprojection_p.h"

	#include "qgeocameratiles_p.h"
	#include "qgeotilerequestmanager_p.h"
	#include "qgeotiledmapscene_p.h"
	#include "qgeocameracapabilities_p.h"
	#include <cmath>

	QT_BEGIN_NAMESPACE
	#define PREFETCH_FRUSTUM_SCALE 2.0

	static const double invLog2 = 1.0 / std::log(2.0);

	static double zoomLevelFrom256(double zoomLevelFor256, double tileSize)
	{
	return std::log( std::pow(2.0, zoomLevelFor256) * 256.0 / tileSize ) * invLog2;
	}

	QGeoTiledMap::QGeoTiledMap(QGeoTiledMappingManagerEngine engine, QObject parent)
	: QGeoMap(*new QGeoTiledMapPrivate(engine), parent)
	{
	Q_D(QGeoTiledMap);

	d->m_tileRequests = new QGeoTileRequestManager(this, engine);

	QObject::connect(engine,&QGeoTiledMappingManagerEngine::tileVersionChanged,
	this,&QGeoTiledMap::handleTileVersionChanged);
	QObject::connect(this, &QGeoMap::cameraCapabilitiesChanged,
	[d](const QGeoCameraCapabilities &oldCameraCapabilities) {
	d->onCameraCapabilitiesChanged(oldCameraCapabilities);
	});
	}

	QGeoTiledMap::QGeoTiledMap(QGeoTiledMapPrivate &dd, QGeoTiledMappingManagerEngine engine, QObject parent)
	: QGeoMap(dd, parent)
	{
	Q_D(QGeoTiledMap);

	d->m_tileRequests = new QGeoTileRequestManager(this, engine);

	QObject::connect(engine,&QGeoTiledMappingManagerEngine::tileVersionChanged,
	this,&QGeoTiledMap::handleTileVersionChanged);
	QObject::connect(this, &QGeoMap::cameraCapabilitiesChanged,
	[d](const QGeoCameraCapabilities &oldCameraCapabilities) {
	d->onCameraCapabilitiesChanged(oldCameraCapabilities);
	});
	}

	QGeoTiledMap::~QGeoTiledMap()
	{
	Q_D(QGeoTiledMap);
	delete d->m_tileRequests;
	d->m_tileRequests = 0;

	if (!d->m_engine.isNull()) {
	QGeoTiledMappingManagerEngine engine = qobject_cast<QGeoTiledMappingManagerEngine>(d->m_engine);
	Q_ASSERT(engine);
	engine->releaseMap(this);
	}
	}

	QGeoTileRequestManager *QGeoTiledMap::requestManager()
	{
	Q_D(QGeoTiledMap);
	return d->m_tileRequests;
	}

	void QGeoTiledMap::updateTile(const QGeoTileSpec &spec)
	{
	Q_D(QGeoTiledMap);
	d->updateTile(spec);
	}

	void QGeoTiledMap::setPrefetchStyle(QGeoTiledMap::PrefetchStyle style)
	{
	Q_D(QGeoTiledMap);
	d->m_prefetchStyle = style;
	}

	QAbstractGeoTileCache *QGeoTiledMap::tileCache()
	{
	Q_D(QGeoTiledMap);
	return d->m_cache;
	}

	QSGNode QGeoTiledMap::updateSceneGraph(QSGNode oldNode, QQuickWindow *window)
	{
	Q_D(QGeoTiledMap);
	return d->updateSceneGraph(oldNode, window);
	}

	void QGeoTiledMap::prefetchData()
	{
	Q_D(QGeoTiledMap);
	d->prefetchTiles();
	}

	void QGeoTiledMap::clearData()
	{
	Q_D(QGeoTiledMap);
	d->m_cache->clearAll();
	d->m_mapScene->clearTexturedTiles();
	d->updateScene();
	sgNodeChanged();
	}

	QGeoMap::Capabilities QGeoTiledMap::capabilities() const
	{
	return Capabilities(SupportsVisibleRegion
	\| SupportsSetBearing
	\| SupportsAnchoringCoordinate
	\| SupportsVisibleArea);
	}

	void QGeoTiledMap::setCopyrightVisible(bool visible)
	{
	Q_D(QGeoTiledMap);
	if (visible == d->m_copyrightVisible)
	return;

	QGeoMap::setCopyrightVisible(visible);
	if (visible)
	evaluateCopyrights(d->m_mapScene->visibleTiles());
	}

	void QGeoTiledMap::clearScene(int mapId)
	{
	Q_D(QGeoTiledMap);
	if (activeMapType().mapId() == mapId)
	d->clearScene();
	}

	void QGeoTiledMap::handleTileVersionChanged()
	{
	Q_D(QGeoTiledMap);
	if (!d->m_engine.isNull()) {
	QGeoTiledMappingManagerEngine* engine = qobject_cast<QGeoTiledMappingManagerEngine*>(d->m_engine);
	Q_ASSERT(engine);
	d->changeTileVersion(engine->tileVersion());
	}
	}

	void QGeoTiledMap::evaluateCopyrights(const QSet<QGeoTileSpec> &visibleTiles)
	{
	Q_UNUSED(visibleTiles);
	}

	QGeoTiledMapPrivate::QGeoTiledMapPrivate(QGeoTiledMappingManagerEngine *engine)
	: QGeoMapPrivate(engine, new QGeoProjectionWebMercator),
	m_cache(engine->tileCache()),
	m_visibleTiles(new QGeoCameraTiles()),
	m_prefetchTiles(new QGeoCameraTiles()),
	m_mapScene(new QGeoTiledMapScene()),
	m_tileRequests(0),
	m_maxZoomLevel(static_cast<int>(std::ceil(m_cameraCapabilities.maximumZoomLevel()))),
	m_minZoomLevel(static_cast<int>(std::ceil(m_cameraCapabilities.minimumZoomLevel()))),
	m_prefetchStyle(QGeoTiledMap::PrefetchTwoNeighbourLayers)
	{
	int tileSize = m_cameraCapabilities.tileSize();
	QString pluginString(engine->managerName() + QLatin1Char('_') + QString::number(engine->managerVersion()));
	m_visibleTiles->setTileSize(tileSize);
	m_prefetchTiles->setTileSize(tileSize);
	m_visibleTiles->setPluginString(pluginString);
	m_prefetchTiles->setPluginString(pluginString);
	m_mapScene->setTileSize(tileSize);
	}

	QGeoTiledMapPrivate::~QGeoTiledMapPrivate()
	{
	// controller_ is a child of map_, don't need to delete it here

	delete m_mapScene;
	delete m_visibleTiles;
	delete m_prefetchTiles;

	// TODO map items are not deallocated!
	// However: how to ensure this is done in rendering thread?
	}

	void QGeoTiledMapPrivate::prefetchTiles()
	{
	if (m_tileRequests && m_prefetchStyle != QGeoTiledMap::NoPrefetching) {

	QSet<QGeoTileSpec> tiles;
	QGeoCameraData camera = m_visibleTiles->cameraData();
	int currentIntZoom = static_cast<int>(std::floor(camera.zoomLevel()));

	m_prefetchTiles->setCameraData(camera);
	m_prefetchTiles->setViewExpansion(PREFETCH_FRUSTUM_SCALE);
	tiles = m_prefetchTiles->createTiles();

	switch (m_prefetchStyle) {

	case QGeoTiledMap::PrefetchNeighbourLayer: {
	double zoomFraction = camera.zoomLevel() - currentIntZoom;
	int nearestNeighbourLayer = zoomFraction > 0.5 ? currentIntZoom + 1 : currentIntZoom - 1;
	if (nearestNeighbourLayer <= m_maxZoomLevel && nearestNeighbourLayer >= m_minZoomLevel) {
	camera.setZoomLevel(nearestNeighbourLayer);
	// Approx heuristic, keeping total # prefetched tiles roughly independent of the
	// fractional zoom level.
	double neighbourScale = (1.0 + zoomFraction)/2.0;
	m_prefetchTiles->setCameraData(camera);
	m_prefetchTiles->setViewExpansion(PREFETCH_FRUSTUM_SCALE * neighbourScale);
	tiles += m_prefetchTiles->createTiles();
	}
	}
	break;

	case QGeoTiledMap::PrefetchTwoNeighbourLayers: {
	// This is a simpler strategy, we just prefetch from layer above and below
	// for the layer below we only use half the size as this fills the screen
	if (currentIntZoom > m_minZoomLevel) {
	camera.setZoomLevel(currentIntZoom - 1);
	m_prefetchTiles->setCameraData(camera);
	m_prefetchTiles->setViewExpansion(0.5);
	tiles += m_prefetchTiles->createTiles();
	}

	if (currentIntZoom < m_maxZoomLevel) {
	camera.setZoomLevel(currentIntZoom + 1);
	m_prefetchTiles->setCameraData(camera);
	m_prefetchTiles->setViewExpansion(1.0);
	tiles += m_prefetchTiles->createTiles();
	}
	}
	break;

	default:
	break;
	}

	m_tileRequests->requestTiles(tiles - m_mapScene->texturedTiles());
	}
	}

	QGeoMapType QGeoTiledMapPrivate::activeMapType()
	{
	return m_visibleTiles->activeMapType();
	}

	// Called before changeCameraData
	void QGeoTiledMapPrivate::onCameraCapabilitiesChanged(const QGeoCameraCapabilities &oldCameraCapabilities)
	{
	// Handle varying min/maxZoomLevel
	if (oldCameraCapabilities.minimumZoomLevel() != m_cameraCapabilities.minimumZoomLevel())
	m_minZoomLevel = static_cast<int>(std::ceil(m_cameraCapabilities.minimumZoomLevel()));
	if (oldCameraCapabilities.maximumZoomLevel() != m_cameraCapabilities.maximumZoomLevel())
	m_maxZoomLevel = static_cast<int>(std::ceil(m_cameraCapabilities.maximumZoomLevel()));

	// Handle varying tile size
	if (oldCameraCapabilities.tileSize() != m_cameraCapabilities.tileSize()) {
	m_visibleTiles->setTileSize(oldCameraCapabilities.tileSize());
	m_prefetchTiles->setTileSize(oldCameraCapabilities.tileSize());
	m_mapScene->setTileSize(oldCameraCapabilities.tileSize());
	}
	}

	void QGeoTiledMapPrivate::changeCameraData(const QGeoCameraData &cameraData)
	{
	Q_Q(QGeoTiledMap);

	QGeoCameraData cam = cameraData;

	// The incoming zoom level is intended for a tileSize of 256.
	// Adapt it to the current tileSize
	double zoomLevel = cameraData.zoomLevel();
	if (m_visibleTiles->tileSize() != 256)
	zoomLevel = zoomLevelFrom256(zoomLevel, m_visibleTiles->tileSize());
	cam.setZoomLevel(zoomLevel);

	// For zoomlevel, "snap" 0.01 either side of a whole number.
	// This is so that when we turn off bilinear scaling, we're
	// snapped to the exact pixel size of the tiles
	int izl = static_cast<int>(std::floor(cam.zoomLevel()));
	float delta = cam.zoomLevel() - izl;

	if (delta > 0.5) {
	izl++;
	delta -= 1.0;
	}

	// TODO: Don't do this if there's tilt or bearing.
	if (qAbs(delta) < 0.01) {
	cam.setZoomLevel(izl);
	}

	m_visibleTiles->setCameraData(cam);
	m_mapScene->setCameraData(cam);

	updateScene();
	q->sgNodeChanged(); // ToDo: explain why emitting twice
	}

	void QGeoTiledMapPrivate::updateScene()
	{
	Q_Q(QGeoTiledMap);
	// detect if new tiles introduced
	const QSet<QGeoTileSpec>& tiles = m_visibleTiles->createTiles();
	bool newTilesIntroduced = !m_mapScene->visibleTiles().contains(tiles);
	m_mapScene->setVisibleTiles(tiles);

	if (newTilesIntroduced && m_copyrightVisible)
	q->evaluateCopyrights(tiles);

	// don't request tiles that are already built and textured
	QMap<QGeoTileSpec, QSharedPointer<QGeoTileTexture> > cachedTiles =
	m_tileRequests->requestTiles(m_visibleTiles->createTiles() - m_mapScene->texturedTiles());

	for (auto it = cachedTiles.cbegin(); it != cachedTiles.cend(); ++it)
	m_mapScene->addTile(it.key(), it.value());

	if (!cachedTiles.isEmpty())
	emit q->sgNodeChanged();
	}

	void QGeoTiledMapPrivate::setVisibleArea(const QRectF &visibleArea)
	{
	Q_Q(QGeoTiledMap);
	const QRectF va = clampVisibleArea(visibleArea);
	if (va == m_visibleArea)
	return;

	m_visibleArea = va;
	m_geoProjection->setVisibleArea(va);

	m_visibleTiles->setVisibleArea(va);
	m_prefetchTiles->setVisibleArea(va);
	m_mapScene->setVisibleArea(va);

	if (m_copyrightVisible)
	q->evaluateCopyrights(m_mapScene->visibleTiles());
	updateScene();
	q->sgNodeChanged(); // ToDo: explain why emitting twice
	}

	QRectF QGeoTiledMapPrivate::visibleArea() const
	{
	return m_visibleArea;
	}

	void QGeoTiledMapPrivate::changeActiveMapType(const QGeoMapType mapType)
	{
	m_visibleTiles->setTileSize(m_cameraCapabilities.tileSize());
	m_prefetchTiles->setTileSize(m_cameraCapabilities.tileSize());
	m_mapScene->setTileSize(m_cameraCapabilities.tileSize());
	m_visibleTiles->setMapType(mapType);
	m_prefetchTiles->setMapType(mapType);
	changeCameraData(m_cameraData); // Updates the zoom level to the possibly new tile size
	// updateScene called in changeCameraData()
	}

	void QGeoTiledMapPrivate::changeTileVersion(int version)
	{
	m_visibleTiles->setMapVersion(version);
	m_prefetchTiles->setMapVersion(version);
	updateScene();
	}

	void QGeoTiledMapPrivate::clearScene()
	{
	m_mapScene->clearTexturedTiles();
	m_mapScene->setVisibleTiles(QSet<QGeoTileSpec>());
	updateScene();
	}

	void QGeoTiledMapPrivate::changeViewportSize(const QSize& size)
	{
	Q_Q(QGeoTiledMap);

	m_visibleTiles->setScreenSize(size);
	m_prefetchTiles->setScreenSize(size);
	m_mapScene->setScreenSize(size);


	if (!size.isEmpty() && m_cache) {
	// absolute minimum size: one tile each side of display, 32-bit colour
	int texCacheSize = (size.width() + m_visibleTiles->tileSize() * 2) *
	(size.height() + m_visibleTiles->tileSize() * 2) * 4;

	// multiply by 3 so the 'recent' list in the cache is big enough for
	// an entire display of tiles
	texCacheSize *= 3;
	// TODO: move this reasoning into the tilecache

	int newSize = qMax(m_cache->minTextureUsage(), texCacheSize);
	m_cache->setMinTextureUsage(newSize);
	}

	if (m_copyrightVisible)
	q->evaluateCopyrights(m_mapScene->visibleTiles());
	updateScene();
	}

	void QGeoTiledMapPrivate::updateTile(const QGeoTileSpec &spec)
	{
	Q_Q(QGeoTiledMap);
	// Only promote the texture up to GPU if it is visible
	if (m_visibleTiles->createTiles().contains(spec)){
	QSharedPointer<QGeoTileTexture> tex = m_tileRequests->tileTexture(spec);
	if (!tex.isNull() && !tex->image.isNull()) {
	m_mapScene->addTile(spec, tex);
	emit q->sgNodeChanged();
	}
	}
	}

	QSGNode QGeoTiledMapPrivate::updateSceneGraph(QSGNode oldNode, QQuickWindow *window)
	{
	return m_mapScene->updateSceneGraph(oldNode, window);
	}

	QT_END_NAMESPACE