consider datum transformation when pasting features (fixes qgis#16846)

doc/api_break.dox

@@ -960,6 +960,7 @@ QgsDatumTransformStore        {#qgis_api_break_3_0_QgsDatumTransformStore}
 
 - transformation() now returns a QgsCoordinateTransform object, not a pointer. An invalid QgsCoordinateTransform will
 be returned in place of a null pointer.
+- transformation() also optional source and destination authid parameters
 
 
 QgsDiagram        {#qgis_api_break_3_0_QgsDiagram}

python/core/qgsdatumtransformstore.sip

@@ -36,12 +36,13 @@ class QgsDatumTransformStore
  :rtype: bool
 %End
 
-    QgsCoordinateTransform transformation( const QgsMapLayer *layer ) const;
+    QgsCoordinateTransform transformation( const QgsMapLayer *layer, QString srcAuthId = QString(), QString dstAuthId = QString() ) const;
 %Docstring
  Will return transform from layer's CRS to current destination CRS.
- Will emit datumTransformInfoRequested signal if the layer has no entry.
  :return: transformation associated with layer, or an invalid QgsCoordinateTransform
  if no transform is associated with the layer
+ \param srcAuthId source CRS (defaults to layer crs)
+ \param dstAuthId destination CRS (defaults to store's crs)
  :rtype: QgsCoordinateTransform
 %End
 

python/gui/qgsmapcanvas.sip

@@ -853,6 +853,7 @@ called when panning is in action, reset indicates end of panning
 
 
 
+
     void updateDatumTransformEntries();
 %Docstring
 Make sure the datum transform store is properly populated

src/app/qgsclipboard.cpp

@@ -36,6 +36,8 @@
 #include "qgsogrutils.h"
 #include "qgsjsonutils.h"
 #include "qgssettings.h"
+#include "qgisapp.h"
+#include "qgsmapcanvas.h"
 
 QgsClipboard::QgsClipboard()
   : QObject()
@@ -59,6 +61,9 @@ void QgsClipboard::replaceWithCopyOf( QgsVectorLayer *src )
   mFeatureFields = src->fields();
   mFeatureClipboard = src->selectedFeatures();
   mCRS = src->crs();
+  layerDestroyed();
+  mSrcLayer = src;
+  connect( mSrcLayer, &QObject::destroyed, this, &QgsClipboard::layerDestroyed );
 
   QgsDebugMsg( "replaced QGis clipboard." );
 
@@ -73,11 +78,19 @@ void QgsClipboard::replaceWithCopyOf( QgsFeatureStore &featureStore )
   mFeatureFields = featureStore.fields();
   mFeatureClipboard = featureStore.features();
   mCRS = featureStore.crs();
+  disconnect( mSrcLayer, &QObject::destroyed, this, &QgsClipboard::layerDestroyed );
+  mSrcLayer = nullptr;
   setSystemClipboard();
   mUseSystemClipboard = false;
   emit changed();
 }
 
+void QgsClipboard::layerDestroyed()
+{
+  disconnect( mSrcLayer, &QObject::destroyed, this, &QgsClipboard::layerDestroyed );
+  mSrcLayer = nullptr;
+}
+
 QString QgsClipboard::generateClipboardText() const
 {
   QgsSettings settings;
@@ -264,7 +277,17 @@ bool QgsClipboard::isEmpty() const
 QgsFeatureList QgsClipboard::transformedCopyOf( const QgsCoordinateReferenceSystem &destCRS, const QgsFields &fields ) const
 {
   QgsFeatureList featureList = copyOf( fields );
-  QgsCoordinateTransform ct( crs(), destCRS );
+
+  QgsCoordinateTransform ct;
+  if ( mSrcLayer )
+  {
+    QgisApp::instance()->mapCanvas()->getDatumTransformInfo( mSrcLayer, crs().authid(), destCRS.authid() );
+    ct = QgisApp::instance()->mapCanvas()->mapSettings().datumTransformStore().transformation( mSrcLayer, crs().authid(), destCRS.authid() );
+  }
+  else
+  {
+    ct = QgsCoordinateTransform( crs(), destCRS );
+  }
 
   QgsDebugMsg( "transforming clipboard." );
   for ( QgsFeatureList::iterator iter = featureList.begin(); iter != featureList.end(); ++iter )

src/app/qgsclipboard.h

@@ -148,6 +148,10 @@ class APP_EXPORT QgsClipboard : public QObject
     //! Emitted when content changed
     void changed();
 
+  private slots:
+    //! source layer destroyed
+    void layerDestroyed();
+
   private:
 
     /**
@@ -180,6 +184,7 @@ class APP_EXPORT QgsClipboard : public QObject
     QgsFeatureList mFeatureClipboard;
     QgsFields mFeatureFields;
     QgsCoordinateReferenceSystem mCRS;
+    QgsVectorLayer *mSrcLayer = nullptr;
 
     //! True when the data from the system clipboard should be read
     bool mUseSystemClipboard;

src/core/qgsdatumtransformstore.cpp

@@ -50,13 +50,15 @@ bool QgsDatumTransformStore::hasEntryForLayer( QgsMapLayer *layer ) const
   return mEntries.contains( layer->id() );
 }
 
-QgsCoordinateTransform QgsDatumTransformStore::transformation( const QgsMapLayer *layer ) const
+QgsCoordinateTransform QgsDatumTransformStore::transformation( const QgsMapLayer *layer, QString srcAuthId, QString dstAuthId ) const
 {
   if ( !layer )
     return QgsCoordinateTransform();
 
-  QString srcAuthId = layer->crs().authid();
-  QString dstAuthId = mDestCRS.authid();
+  if ( srcAuthId.isEmpty() )
+    srcAuthId = layer->crs().authid();
+  if ( dstAuthId.isEmpty() )
+    dstAuthId = mDestCRS.authid();
 
   if ( srcAuthId == dstAuthId )
   {

src/core/qgsdatumtransformstore.h

@@ -45,11 +45,12 @@ class CORE_EXPORT QgsDatumTransformStore
 
     /**
      * Will return transform from layer's CRS to current destination CRS.
-     * Will emit datumTransformInfoRequested signal if the layer has no entry.
      * \returns transformation associated with layer, or an invalid QgsCoordinateTransform
      * if no transform is associated with the layer
+     * \param srcAuthId source CRS (defaults to layer crs)
+     * \param dstAuthId destination CRS (defaults to store's crs)
      */
-    QgsCoordinateTransform transformation( const QgsMapLayer *layer ) const;
+    QgsCoordinateTransform transformation( const QgsMapLayer *layer, QString srcAuthId = QString(), QString dstAuthId = QString() ) const;
 
     void readXml( const QDomNode &parentNode );