Use a sensible default map extent for .gpx files with no data in them (as

produced by the create gpx layer command). Fixes a problem where digitising
didn't work when loading a blank .gpx file as the first layer in qgis.


git-svn-id: http://svn.osgeo.org/qgis/trunk@6279 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: g_j_m

src/providers/gpx/gpsdata.cpp

@@ -135,6 +135,15 @@ QgsRect* GPSData::getExtent() const {
   return new QgsRect(xMin, yMin, xMax, yMax);
 }
 
+void GPSData::setNoDataExtent() {
+  if (getNumberOfWaypoints() + getNumberOfRoutes() + getNumberOfTracks() == 0)
+  {
+    xMin = -1.0;
+    xMax =  1.0;
+    yMin = -1.0;
+    yMax =  1.0;
+  }
+}
 
 int GPSData::getNumberOfWaypoints() const {
   return waypoints.size();
@@ -345,7 +354,9 @@ GPSData* GPSData::getData(const QString& filename) {
     XML_ParserFree(p);
     if (failed)
       return 0;
-    
+
+    data->setNoDataExtent();
+
     dataObjects[filename] = std::pair<GPSData*, unsigned>(data, 0);
   }
   else

src/providers/gpx/gpsdata.h

@@ -132,7 +132,9 @@ class GPSData {
       which is the bounding box for this dataset. You'll have to deallocate it
       yourself. */
   QgsRect* getExtent() const;
-  
+
+  /** Sets a default sensible extent. Only applies when there are no actual data. */
+  void setNoDataExtent();
 
   /** Returns the number of waypoints in this dataset. */
   int getNumberOfWaypoints() const;