Consider datum transform in raster projector

python/core/raster/qgsrasterprojector.sip

@@ -13,6 +13,18 @@ class QgsRasterProjector : QgsRasterInterface
      * it calculates grid of points in source CRS for target CRS + extent
      * which are used to calculate affine transformation matrices.
      */
+
+    QgsRasterProjector(
+          QgsCoordinateReferenceSystem theSrcCRS,
+          QgsCoordinateReferenceSystem theDestCRS,
+          int theSrcDatumTransform,
+          int theDestDatumTransform,
+          QgsRectangle theDestExtent,
+          int theDestRows, int theDestCols,
+          double theMaxSrcXRes, double theMaxSrcYRes,
+          QgsRectangle theExtent
+        );
+
     QgsRasterProjector(
       QgsCoordinateReferenceSystem theSrcCRS,
       QgsCoordinateReferenceSystem theDestCRS,
@@ -39,7 +51,7 @@ class QgsRasterProjector : QgsRasterInterface
     int dataType( int bandNo ) const;
 
     /** \brief set source and destination CRS */
-    void setCRS( const QgsCoordinateReferenceSystem & theSrcCRS, const QgsCoordinateReferenceSystem & theDestCRS );
+    void setCRS( const QgsCoordinateReferenceSystem & theSrcCRS, const QgsCoordinateReferenceSystem & theDestCRS, int srcDatumTransform = -1, int destDatumTransform = -1 );
 
     /** \brief Get source CRS */
     QgsCoordinateReferenceSystem srcCrs() const;

src/core/raster/qgsrasterlayer.cpp

@@ -333,11 +333,15 @@ bool QgsRasterLayer::draw( QgsRenderContext& rendererContext )
   {
     myRasterViewPort->mSrcCRS = crs();
     myRasterViewPort->mDestCRS = rendererContext.coordinateTransform()->destCRS();
+    myRasterViewPort->mSrcDatumTransform = rendererContext.coordinateTransform()->sourceDatumTransform();
+    myRasterViewPort->mDestDatumTransform = rendererContext.coordinateTransform()->destinationDatumTransform();
   }
   else
   {
     myRasterViewPort->mSrcCRS = QgsCoordinateReferenceSystem(); // will be invalid
     myRasterViewPort->mDestCRS = QgsCoordinateReferenceSystem(); // will be invalid
+    myRasterViewPort->mSrcDatumTransform = -1;
+    myRasterViewPort->mDestDatumTransform = -1;
   }
 
   // get dimensions of clipped raster image in device coordinate space (this is the size of the viewport)
@@ -423,7 +427,7 @@ void QgsRasterLayer::draw( QPainter * theQPainter,
   // params in QgsRasterProjector
   if ( projector )
   {
-    projector->setCRS( theRasterViewPort->mSrcCRS, theRasterViewPort->mDestCRS );
+    projector->setCRS( theRasterViewPort->mSrcCRS, theRasterViewPort->mDestCRS, theRasterViewPort->mSrcDatumTransform, theRasterViewPort->mDestDatumTransform );
   }
 
   // Drawer to pipe?
@@ -1257,6 +1261,8 @@ QPixmap QgsRasterLayer::previewAsPixmap( QSize size, QColor bgColor )
   myRasterViewPort->mDrawnExtent = myExtent;
   myRasterViewPort->mSrcCRS = QgsCoordinateReferenceSystem(); // will be invalid
   myRasterViewPort->mDestCRS = QgsCoordinateReferenceSystem(); // will be invalid
+  myRasterViewPort->mSrcDatumTransform = -1;
+  myRasterViewPort->mDestDatumTransform = -1;
 
   QgsMapToPixel *myMapToPixel = new QgsMapToPixel( myMapUnitsPerPixel );