Support map zoom to level 23

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/QGCMapEngine.cpp

@@ -222,6 +222,15 @@ QGCMapEngine::cacheTile(QString type, const QString& hash, const QByteArray& ima
 QString
 QGCMapEngine::getTileHash(QString type, int x, int y, int z)
 {
+#if 0
+    int maxCachedZoom = 15;
+    if (z > maxCachedZoom) {
+        double unZoomFactor = qPow(2, z - maxCachedZoom);
+        x = (double)x / unZoomFactor;
+        y = (double)y / unZoomFactor;
+        z = maxCachedZoom;
+    }
+#endif
     return QString::asprintf("%010d%08d%08d%03d", getQGCMapEngine()->urlFactory()->getIdFromType(type), x, y, z);
 }
 

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

src/QtLocationPlugin/QGeoMapReplyQGC.cpp

@@ -54,6 +54,7 @@
 #include "TerrainTile.h"
 
 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");
@@ -135,12 +142,20 @@ QGeoTiledMapReplyQGC::networkReplyFinished()
         }
         emit terrainDone(a, QNetworkReply::NoError);
     } else {
+        if (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);
     }
     _clearReply();

src/QtLocationPlugin/QGeoMapReplyQGC.h

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