Show warnings on fallback transform

nyalldawson · Feb 17, 2020 · 1684ff1 · 1684ff1
1 parent ec78431
commit 1684ff1
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diff --git a/src/app/qgsappcoordinateoperationhandlers.cpp b/src/app/qgsappcoordinateoperationhandlers.cpp
@@ -56,10 +56,19 @@ QgsAppMissingGridHandler::QgsAppMissingGridHandler( QObject *parent )
     emit missingGridUsedByContextHandler( sourceCrs, destinationCrs, desired );
   } );
 
+  QgsCoordinateTransform::setFallbackOperationOccurredHandler( [ = ]( const QgsCoordinateReferenceSystem & sourceCrs,
+      const QgsCoordinateReferenceSystem & destinationCrs,
+      const QgsDatumTransform::TransformDetails & desired,
+      const QgsDatumTransform::TransformDetails & used )
+  {
+    emit fallbackOperationOccurred( sourceCrs, destinationCrs, desired, used );
+  } );
+
   connect( this, &QgsAppMissingGridHandler::missingRequiredGrid, this, &QgsAppMissingGridHandler::onMissingRequiredGrid, Qt::QueuedConnection );
   connect( this, &QgsAppMissingGridHandler::missingPreferredGrid, this, &QgsAppMissingGridHandler::onMissingPreferredGrid, Qt::QueuedConnection );
   connect( this, &QgsAppMissingGridHandler::coordinateOperationCreationError, this, &QgsAppMissingGridHandler::onCoordinateOperationCreationError, Qt::QueuedConnection );
   connect( this, &QgsAppMissingGridHandler::missingGridUsedByContextHandler, this, &QgsAppMissingGridHandler::onMissingGridUsedByContextHandler, Qt::QueuedConnection );
+  connect( this, &QgsAppMissingGridHandler::fallbackOperationOccurred, this, &QgsAppMissingGridHandler::onFallbackOperationOccurred, Qt::QueuedConnection );
 
   connect( QgsProject::instance(), &QgsProject::cleared, this, [ = ] { mAlreadyWarnedPairsForProject.clear(); } );
 
@@ -265,6 +274,30 @@ void QgsAppMissingGridHandler::onMissingGridUsedByContextHandler( const QgsCoord
   bar->pushWidget( widget, Qgis::Critical, 0 );
 }
 
+void QgsAppMissingGridHandler::onFallbackOperationOccurred( const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QgsDatumTransform::TransformDetails &desired, const QgsDatumTransform::TransformDetails &used )
+{
+  //  if ( !shouldWarnAboutPairForCurrentProject( sourceCrs, destinationCrs ) )
+  //    return;
+
+  const QString shortMessage = tr( "Used a fallback transform from %1 to %2" ).arg( sourceCrs.userFriendlyIdentifier( QgsCoordinateReferenceSystem::ShortString ), destinationCrs.userFriendlyIdentifier( QgsCoordinateReferenceSystem::ShortString ) );
+  const QString longMessage = tr( "<p>An alternative transform was used when transforming coordinates between <i>%1</i> and <i>%2</i>.</p><p style=\"color: red\">I wanted to use %3</p>" ).arg( sourceCrs.userFriendlyIdentifier(), destinationCrs.userFriendlyIdentifier(), desired.proj );
+
+  QgsMessageBar *bar = QgisApp::instance()->messageBar();
+  QgsMessageBarItem *widget = bar->createMessage( QString(), shortMessage );
+  QPushButton *detailsButton = new QPushButton( tr( "Details" ) );
+  connect( detailsButton, &QPushButton::clicked, this, [longMessage]
+  {
+    // dlg has deleted on close
+    QgsMessageOutput * dlg( QgsMessageOutput::createMessageOutput() );
+    dlg->setTitle( tr( "Fallback Transform Occurred" ) );
+    dlg->setMessage( longMessage, QgsMessageOutput::MessageHtml );
+    dlg->showMessage();
+  } );
+
+  widget->layout()->addWidget( detailsButton );
+  bar->pushWidget( widget, Qgis::Critical, 0 );
+}
+
 bool QgsAppMissingGridHandler::shouldWarnAboutPair( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &dest )
 {
   if ( mAlreadyWarnedPairs.contains( qMakePair( source, dest ) ) || mAlreadyWarnedPairs.contains( qMakePair( dest, source ) ) )

diff --git a/src/app/qgsappcoordinateoperationhandlers.h b/src/app/qgsappcoordinateoperationhandlers.h
@@ -49,6 +49,11 @@ class QgsAppMissingGridHandler : public QObject
                                           const QgsCoordinateReferenceSystem &destinationCrs,
                                           const QgsDatumTransform::TransformDetails &desired );
 
+    void fallbackOperationOccurred( const QgsCoordinateReferenceSystem &sourceCrs,
+                                    const QgsCoordinateReferenceSystem &destinationCrs,
+                                    const QgsDatumTransform::TransformDetails &desired,
+                                    const QgsDatumTransform::TransformDetails &used );
+
   private slots:
 
     void onMissingRequiredGrid( const QgsCoordinateReferenceSystem &sourceCrs,
@@ -67,6 +72,12 @@ class QgsAppMissingGridHandler : public QObject
     void onMissingGridUsedByContextHandler( const QgsCoordinateReferenceSystem &sourceCrs,
                                             const QgsCoordinateReferenceSystem &destinationCrs,
                                             const QgsDatumTransform::TransformDetails &desired );
+
+    void onFallbackOperationOccurred( const QgsCoordinateReferenceSystem &sourceCrs,
+                                      const QgsCoordinateReferenceSystem &destinationCrs,
+                                      const QgsDatumTransform::TransformDetails &desired,
+                                      const QgsDatumTransform::TransformDetails &used );
+
   private:
 
     bool shouldWarnAboutPair( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &dest );

diff --git a/src/core/qgscoordinatetransform.cpp b/src/core/qgscoordinatetransform.cpp
@@ -49,6 +49,11 @@ QReadWriteLock QgsCoordinateTransform::sCacheLock;
 QMultiHash< QPair< QString, QString >, QgsCoordinateTransform > QgsCoordinateTransform::sTransforms; //same auth_id pairs might have different datum transformations
 bool QgsCoordinateTransform::sDisableCache = false;
 
+std::function< void( const QgsCoordinateReferenceSystem &sourceCrs,
+                     const QgsCoordinateReferenceSystem &destinationCrs,
+                     const QgsDatumTransform::TransformDetails &desiredOperation,
+                     const QgsDatumTransform::TransformDetails &usedOperation )> QgsCoordinateTransform::sFallbackOperationOccurredHandler = nullptr;
+
 QgsCoordinateTransform::QgsCoordinateTransform()
 {
   d = new QgsCoordinateTransformPrivate();
@@ -637,12 +642,14 @@ void QgsCoordinateTransform::transformCoords( int numPoints, double *x, double *
     return;
   }
 
+#if PROJ_VERSION_MAJOR>=6
   double *xprev = new double[ numPoints ];
   memcpy( xprev, x, sizeof( double ) * numPoints );
   double *yprev = new double[ numPoints ];
   memcpy( yprev, y, sizeof( double ) * numPoints );
   double *zprev = new double[ numPoints ];
   memcpy( zprev, z, sizeof( double ) * numPoints );
+#endif
 
 #ifdef COORDINATE_TRANSFORM_VERBOSE
   double xorg = *x;
@@ -753,11 +760,21 @@ void QgsCoordinateTransform::transformCoords( int numPoints, double *x, double *
         memcpy( y, yprev, sizeof( double ) * numPoints );
         memcpy( z, zprev, sizeof( double ) * numPoints );
       }
+
+      if ( sFallbackOperationOccurredHandler )
+      {
+        QgsDatumTransform::TransformDetails desired = instantiatedCoordinateOperationDetails();
+        QgsDatumTransform::TransformDetails used = QgsDatumTransform::transformDetailsFromPj( transform );
+        sFallbackOperationOccurredHandler( d->mSourceCRS, d->mDestCRS, desired, used );
+      }
     }
   }
   delete [] xprev;
+  xprev = nullptr;
   delete [] yprev;
+  yprev = nullptr;
   delete [] zprev;
+  zprev = nullptr;
 #endif
   if ( projResult != 0 )
   {
@@ -1091,3 +1108,8 @@ void QgsCoordinateTransform::setCustomMissingGridUsedByContextHandler( const std
 {
   QgsCoordinateTransformPrivate::setCustomMissingGridUsedByContextHandler( handler );
 }
+
+void QgsCoordinateTransform::setFallbackOperationOccurredHandler( const std::function<void ( const QgsCoordinateReferenceSystem &, const QgsCoordinateReferenceSystem &, const QgsDatumTransform::TransformDetails &, const QgsDatumTransform::TransformDetails & )> &handler )
+{
+  sFallbackOperationOccurredHandler = handler;
+}
diff --git a/src/core/qgscoordinatetransform.h b/src/core/qgscoordinatetransform.h
@@ -555,6 +555,19 @@ class CORE_EXPORT QgsCoordinateTransform
     static void setCustomMissingGridUsedByContextHandler( const std::function< void( const QgsCoordinateReferenceSystem &sourceCrs,
         const QgsCoordinateReferenceSystem &destinationCrs,
         const QgsDatumTransform::TransformDetails &desiredOperation )> &handler );
+
+
+    /**
+     * Sets a custom \a handler to use when the desired coordinate operation for use between \a sourceCrs and
+     * \a destinationCrs failed and an alternative fallback \a usedOperation was utilised instead.
+     *
+     * \since QGIS 3.10.3
+     */
+    static void setFallbackOperationOccurredHandler( const std::function< void( const QgsCoordinateReferenceSystem &sourceCrs,
+        const QgsCoordinateReferenceSystem &destinationCrs,
+        const QgsDatumTransform::TransformDetails &desiredOperation,
+        const QgsDatumTransform::TransformDetails &usedOperation )> &handler );
+
 #endif
 
 #ifndef SIP_RUN
@@ -596,6 +609,12 @@ class CORE_EXPORT QgsCoordinateTransform
     static QMultiHash< QPair< QString, QString >, QgsCoordinateTransform > sTransforms; //same auth_id pairs might have different datum transformations
     static bool sDisableCache;
 
+
+    static std::function< void( const QgsCoordinateReferenceSystem &sourceCrs,
+                                const QgsCoordinateReferenceSystem &destinationCrs,
+                                const QgsDatumTransform::TransformDetails &desiredOperation,
+                                const QgsDatumTransform::TransformDetails &usedOperation )> sFallbackOperationOccurredHandler;
+
 };
 
 //! Output stream operator