Refactored DataProvider to push some vector specific methods down to qgsvectordataprovider. Doing this will allow me to use the dataprovider ABC for the soon to be implemented raster providers - which will in turn provide a cleaner based for projection support. Also added getProjectionWKT virtual method to maplayer and did (concrete) implementation for raster and (placeholder) implementation for vector. Next step will be to implement a getProjectionWKT method in the dataprovider interface with maplayer will delegate to, allowing the retrival of projection info to be handled on a case by case basis in each provider...

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@2544 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/qgsdataprovider.h

@@ -36,17 +36,8 @@ public:
   */
   virtual ~QgsDataProvider() {};
 
-  /**
-  * Select features based on a bounding rectangle. Features can be retrieved 
-  * with calls to getFirstFeature and getNextFeature. Request for features 
-  * for use in drawing the map canvas should set useIntersect to false.
-  * @param mbr QgsRect containing the extent to use in selecting features
-  * @param useIntersect If true, use the intersects function to select features
-  * rather than the PostGIS && operator that selects based on bounding box
-  * overlap.
-  *
-  */
-  virtual void select(QgsRect *mbr, bool useIntersect=false)=0;
+
+  
   /** 
     * Set the data source specification. This may be a path or database
   * connection string
@@ -94,14 +85,7 @@ public:
   { 
      // NOP by default 
   }
-  /**
-   * Update the feature count based on current spatial filter. If not
-   * overridden in the data provider this function returns -1
-   */
-  virtual long updateFeatureCount()
-  {
-    return -1;
-  }
+
   /**
    * Update the extents of the layer. Not implemented by default
    */

src/qgsmaplayer.h

@@ -38,6 +38,7 @@ class QgsLegendItem;
 class QDomNode;
 class QDomDocument;
 class QEvent;
+class QgsCoordinateTransform;
 
 /** \class QgsMapLayer
  * \brief Base class for all map layer types.
@@ -347,12 +348,14 @@ signals:
 
 protected:
 
+    /** Used to ask the layer for its projection as a WKT string. Must be reimplemented by each provider. */
+    virtual QString getProjectionWKT()  = 0 ;
+  
     /** called by readXML(), used by children to read state specific to them from
         project files.
     */
     virtual bool readXML_( QDomNode & layer_node );
 
-
     /** called by writeXML(), used by children to write state specific to them to
         project files.
     */
@@ -428,6 +431,9 @@ private:                       // Private attributes
     //! Tag for embedding additional information
     QString tag;
 
+    //! A QgsCoordinateTransform is used for on the fly reprojection of map layers
+    QgsCoordinateTransform * gCoordinateTransfrom;
+    
     /**  true if visible ? */
     bool m_visible;
 

src/qgsrasterlayer.h

@@ -353,6 +353,8 @@ public:
     /** \brief The destuctor.  */
     ~QgsRasterLayer();
 
+    /** \brief Query gdal to find out the WKT projection string for this layer. This implements the virtual method of the same name defined in QgsMapLayer*/
+    QString getProjectionWKT() { return QString (gdalDataset->GetProjectionRef());};
 
     /** \brief Draws a thumbnail of the rasterlayer into the supplied pixmap pointer */
      void drawThumbnail(QPixmap * theQPixmap);

src/qgsvectordataprovider.h

@@ -26,7 +26,25 @@ class QgsVectorDataProvider: public QgsDataProvider
     QgsVectorDataProvider();
 
     virtual ~QgsVectorDataProvider() {};
-
+  /**
+  * Select features based on a bounding rectangle. Features can be retrieved 
+  * with calls to getFirstFeature and getNextFeature. Request for features 
+  * for use in drawing the map canvas should set useIntersect to false.
+  * @param mbr QgsRect containing the extent to use in selecting features
+  * @param useIntersect If true, use the intersects function to select features
+  * rather than the PostGIS && operator that selects based on bounding box
+  * overlap.
+  *
+  */
+  virtual void select(QgsRect *mbr, bool useIntersect=false)=0;
+  /**
+  * Update the feature count based on current spatial filter. If not
+  * overridden in the data provider this function returns -1
+  */
+  virtual long updateFeatureCount()
+  {
+    return -1;
+  }
     /** 
      * Get the first feature resulting from a select operation
      * @return QgsFeature

src/qgsvectorlayer.h

@@ -25,7 +25,7 @@ class QLibrary;
 class QgsMapToPixel;
 class OGRLayer;
 class OGRDataSource;
-class QgsDataProvider;
+class QgsData;
 class QgsRenderer;
 class QgsLegendItem;
 class QgsDlgVectorLayerProperties;
@@ -93,7 +93,12 @@ class QgsVectorLayer : public QgsMapLayer
 
   QgsVectorDataProvider * getDataProvider();
 
-
+  /** \brief Query gdal to find out the WKT projection string for this layer. This implements the virtual method of the same name defined in QgsMapLayer*/
+  QString getProjectionWKT() 
+  { 
+  //delegate to data provider...
+  };
+    
   QgsLabel *label();
 
   QgsAttributeAction* actions() { return &mActions; }