Merge pull request #8902 from DonLakeFlyer/ZoomTo23

Support map zoom to level 23

ChangeLog.md

@@ -4,6 +4,7 @@ Note: This file only contains high level features or important fixes.
 
 ## 4.1 - Daily build
 
+* Maps: Support zoom up to level 23 even if map provider doesn't provide tiles that high
 * Settings/Mavlink: Add ability to forward mavlink traffic out specified UDP port
 * Support mavlink terrain protocol which queries gcs for terrain height information. Allows planning missions with TERRAIN\_FRAME.
 * Fly: New instrument values display/editing support

qgcresources.qrc

@@ -22,6 +22,7 @@
         <file alias="gear-black.svg">resources/gear-black.svg</file>
         <file alias="gear-white.svg">resources/gear-white.svg</file>
         <file alias="helicoptericon.svg">resources/helicoptericon.svg</file>
+        <file alias="BingNoTileBytes.dat">resources/BingNoTileBytes.dat</file>
         <file alias="JoystickBezel.png">resources/JoystickBezel.png</file>
         <file alias="JoystickBezelLight.png">resources/JoystickBezelLight.png</file>
         <file alias="land.svg">resources/land.svg</file>

src/QtLocationPlugin/BingMapProvider.h

@@ -20,6 +20,9 @@ public:
 
     ~BingMapProvider() = default;
 
+    bool _isBingProvider() const override { return true; }
+
+
 protected:
     const QString _versionBingMaps = QStringLiteral("563");
 };

src/QtLocationPlugin/MapProvider.cpp

@@ -89,10 +89,6 @@ int MapProvider::lat2tileY(const double lat, const int z) const {
         2.0 * pow(2.0, z)));
 }
 
-bool MapProvider::_isElevationProvider() const {
-    return false;
-}
-
 QGCTileSet MapProvider::getTileCount(const int zoom, const double topleftLon,
                                      const double topleftLat, const double bottomRightLon,
                                      const double bottomRightLat) const {

src/QtLocationPlugin/MapProvider.h

@@ -45,7 +45,8 @@ public:
 
     virtual int lat2tileY(const double lat, const int z) const;
 
-    virtual bool _isElevationProvider() const;
+    virtual bool _isElevationProvider() const { return false; }
+    virtual bool _isBingProvider() const { return false; }
 
     virtual QGCTileSet getTileCount(const int zoom, const double topleftLon,
                                      const double topleftLat, const double bottomRightLon,

src/QtLocationPlugin/QGCMapUrlEngine.cpp

@@ -155,6 +155,17 @@ QString UrlFactory::getTypeFromId(int id) {
     return "";
 }
 
+MapProvider* UrlFactory::getMapProviderFromId(int id)
+{
+    QString type = getTypeFromId(id);
+    if (!type.isEmpty()) {
+        if (_providersTable.find(type) != _providersTable.end()) {
+            return _providersTable[type];
+        }
+    }
+    return nullptr;
+}
+
 // Todo : qHash produce a uint bigger than max(int)
 // There is still a low probability for this to
 // generate similar hash for different types

src/QtLocationPlugin/QGCMapUrlEngine.h

@@ -24,7 +24,7 @@
 #include "MapboxMapProvider.h"
 #include "ElevationMapProvider.h"
 
-#define MAX_MAP_ZOOM (20.0)
+#define MAX_MAP_ZOOM (23.0)
 
 class UrlFactory : public QObject {
     Q_OBJECT
@@ -48,6 +48,7 @@ public:
 
     int getIdFromType(QString type);
     QString getTypeFromId(int id);
+    MapProvider* getMapProviderFromId(int id);
 
     QGCTileSet getTileCount(int zoom, double topleftLon, double topleftLat,
                             double bottomRightLon, double bottomRightLat,

src/QtLocationPlugin/QGeoMapReplyQGC.cpp

@@ -53,7 +53,8 @@
 #include <QFile>
 #include "TerrainTile.h"
 
-int QGeoTiledMapReplyQGC::_requestCount = 0;
+int         QGeoTiledMapReplyQGC::_requestCount = 0;
+QByteArray  QGeoTiledMapReplyQGC::_bingNoTileImage;
 
 //-----------------------------------------------------------------------------
 QGeoTiledMapReplyQGC::QGeoTiledMapReplyQGC(QNetworkAccessManager *networkManager, const QNetworkRequest &request, const QGeoTileSpec &spec, QObject *parent)
@@ -62,6 +63,12 @@ QGeoTiledMapReplyQGC::QGeoTiledMapReplyQGC(QNetworkAccessManager *networkManager
     , _request(request)
     , _networkManager(networkManager)
 {
+    if (_bingNoTileImage.count() == 0) {
+        QFile file(":/res/BingNoTileBytes.dat");
+        file.open(QFile::ReadOnly);
+        _bingNoTileImage = file.readAll();
+        file.close();
+    }
     if(_request.url().isEmpty()) {
         if(!_badMapbox.size()) {
             QFile b(":/res/notile.png");
@@ -122,7 +129,8 @@ QGeoTiledMapReplyQGC::networkReplyFinished()
         return;
     }
     QByteArray a = _reply->readAll();
-    QString format = getQGCMapEngine()->urlFactory()->getImageFormat(tileSpec().mapId(), a);
+    UrlFactory* urlFactory = getQGCMapEngine()->urlFactory();
+    QString format = urlFactory->getImageFormat(tileSpec().mapId(), a);
     //-- Test for a specialized, elevation data (not map tile)
     if( getQGCMapEngine()->urlFactory()->isElevation(tileSpec().mapId())){
         a = TerrainTile::serialize(a);
@@ -135,11 +143,20 @@ QGeoTiledMapReplyQGC::networkReplyFinished()
         }
         emit terrainDone(a, QNetworkReply::NoError);
     } else {
-        //-- This is a map tile. Process and cache it if valid.
-        setMapImageData(a);
-        if(!format.isEmpty()) {
-            setMapImageFormat(format);
-            getQGCMapEngine()->cacheTile(getQGCMapEngine()->urlFactory()->getTypeFromId(tileSpec().mapId()), tileSpec().x(), tileSpec().y(), tileSpec().zoom(), a, format);
+        MapProvider* mapProvider = urlFactory->getMapProviderFromId(tileSpec().mapId());
+        if (mapProvider && mapProvider->_isBingProvider() && a.size() && _bingNoTileImage.size() && a == _bingNoTileImage) {
+            // Bing doesn't return an error if you request a tile above supported zoom level
+            // It instead returns an image of a missing tile graphic. We need to detect that
+            // and error out so Qt will deal with zooming correctly even if it doesn't have the tile.
+            // This allows us to zoom up to level 23 even though the tiles don't actually exist
+            setError(QGeoTiledMapReply::CommunicationError, "Bing tile above zoom level");
+        } else {
+            //-- This is a map tile. Process and cache it if valid.
+            setMapImageData(a);
+            if(!format.isEmpty()) {
+                setMapImageFormat(format);
+                getQGCMapEngine()->cacheTile(getQGCMapEngine()->urlFactory()->getTypeFromId(tileSpec().mapId()), tileSpec().x(), tileSpec().y(), tileSpec().zoom(), a, format);
+            }
         }
         setFinished(true);
     }

src/QtLocationPlugin/QGeoMapReplyQGC.h

@@ -81,6 +81,7 @@ private:
     QByteArray              _badMapbox;
     QByteArray              _badTile;
     QTimer                  _timer;
+    static QByteArray       _bingNoTileImage;
     static int              _requestCount;
 };