Don't reset mesh layer styling when changing data source for layer

This breaks fixing mesh layer paths when restoring projects with broken mesh layers -- fixing the path causes the existing style to be lost. Fixes #45391
qgis · Oct 6, 2021 · b48d7dc · b48d7dc
1 parent 16200ca
commit b48d7dc
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Showing 4 changed files with 49 additions and 3 deletions.
diff --git a/python/core/auto_generated/mesh/qgsmeshlayer.sip.in b/python/core/auto_generated/mesh/qgsmeshlayer.sip.in
@@ -94,6 +94,8 @@ Constructor for LayerOptions with optional ``transformContext``.
 
       QgsCoordinateTransformContext transformContext;
 
+      bool loadDefaultStyle;
+
       bool skipCrsValidation;
     };
 
@@ -161,6 +163,8 @@ QgsMeshLayer cannot be copied.
 
     virtual bool supportsEditing() const;
 
+    virtual QString loadDefaultStyle( bool &resultFlag /Out/ ) ${SIP_FINAL};
+
 
     QString providerType() const;
 %Docstring

diff --git a/src/core/mesh/qgsmeshlayer.cpp b/src/core/mesh/qgsmeshlayer.cpp
@@ -57,6 +57,10 @@ QgsMeshLayer::QgsMeshLayer( const QString &meshLayerPath,
 
   const QgsDataProvider::ProviderOptions providerOptions { options.transformContext };
   QgsDataProvider::ReadFlags flags = QgsDataProvider::ReadFlags();
+  if ( options.loadDefaultStyle )
+  {
+    flags |= QgsDataProvider::FlagLoadDefaultStyle;
+  }
   if ( mReadFlags & QgsMapLayer::FlagTrustLayerMetadata )
   {
     flags |= QgsDataProvider::FlagTrustDataSource;
@@ -65,7 +69,7 @@ QgsMeshLayer::QgsMeshLayer( const QString &meshLayerPath,
   resetDatasetGroupTreeItem();
   setLegend( QgsMapLayerLegend::defaultMeshLegend( this ) );
 
-  if ( isValid() )
+  if ( isValid() && options.loadDefaultStyle )
     setDefaultRendererSettings( mDatasetGroupStore->datasetGroupIndexes() );
 
   connect( mDatasetGroupStore.get(), &QgsMeshDatasetGroupStore::datasetGroupsAdded, this, &QgsMeshLayer::onDatasetGroupsAdded );
@@ -201,6 +205,20 @@ bool QgsMeshLayer::supportsEditing() const
   return driverMetadata.capabilities() & QgsMeshDriverMetadata::CanWriteMeshData;
 }
 
+QString QgsMeshLayer::loadDefaultStyle( bool &resultFlag )
+{
+  if ( mDataProvider )
+  {
+    for ( int i = 0; i < mDataProvider->datasetGroupCount(); ++i )
+      assignDefaultStyleToDatasetGroup( i );
+
+    emit rendererChanged();
+    emitStyleChanged();
+  }
+
+  return QgsMapLayer::loadDefaultStyle( resultFlag );
+}
+
 bool QgsMeshLayer::addDatasets( const QString &path, const QDateTime &defaultReferenceTime )
 {
   const bool isTemporalBefore = dataProvider()->temporalCapabilities()->hasTemporalCapabilities();
@@ -1694,7 +1712,12 @@ bool QgsMeshLayer::setDataProvider( QString const &provider, const QgsDataProvid
   }
 
   mDataProvider->setTemporalUnit( mTemporalUnit );
+
+  // temporarily disconnect from datasetGroupsAdded -- we don't want to reset the style for reconnected dataset groups
+  disconnect( mDatasetGroupStore.get(), &QgsMeshDatasetGroupStore::datasetGroupsAdded, this, &QgsMeshLayer::onDatasetGroupsAdded );
   mDatasetGroupStore->setPersistentProvider( mDataProvider, mExtraDatasetUri );
+  connect( mDatasetGroupStore.get(), &QgsMeshDatasetGroupStore::datasetGroupsAdded, this, &QgsMeshLayer::onDatasetGroupsAdded );
+
   setCrs( mDataProvider->crs() );
 
   if ( provider == QLatin1String( "mesh_memory" ) )
@@ -1703,8 +1726,16 @@ bool QgsMeshLayer::setDataProvider( QString const &provider, const QgsDataProvid
     mDataSource = mDataSource + QStringLiteral( "&uid=%1" ).arg( QUuid::createUuid().toString() );
   }
 
-  for ( int i = 0; i < mDataProvider->datasetGroupCount(); ++i )
-    assignDefaultStyleToDatasetGroup( i );
+  if ( flags & QgsDataProvider::FlagLoadDefaultStyle )
+  {
+    for ( int i = 0; i < mDataProvider->datasetGroupCount(); ++i )
+      assignDefaultStyleToDatasetGroup( i );
+
+    emit rendererChanged();
+    emitStyleChanged();
+  }
+
+  temporalProperties()->setIsActive( mDatasetGroupStore->hasTemporalCapabilities() );
 
   connect( mDataProvider, &QgsMeshDataProvider::dataChanged, this, &QgsMeshLayer::dataChanged );
 

diff --git a/src/core/mesh/qgsmeshlayer.h b/src/core/mesh/qgsmeshlayer.h
@@ -112,8 +112,17 @@ class CORE_EXPORT QgsMeshLayer : public QgsMapLayer
         : transformContext( transformContext )
       {}
 
+      /**
+       * Coordinate transform context
+       */
       QgsCoordinateTransformContext transformContext;
 
+      /**
+       * Set to TRUE if the default layer style should be loaded.
+       * \since QGIS 3.22
+       */
+      bool loadDefaultStyle = true;
+
       /**
        * Controls whether the layer is allowed to have an invalid/unknown CRS.
        *
@@ -182,6 +191,7 @@ class CORE_EXPORT QgsMeshLayer : public QgsMapLayer
     QString htmlMetadata() const override;
     bool isEditable() const override;
     bool supportsEditing() const override;
+    QString loadDefaultStyle( bool &resultFlag SIP_OUT ) FINAL;
 
     //! Returns the provider type for this layer
     QString providerType() const;

diff --git a/src/core/qgsmaplayerfactory.cpp b/src/core/qgsmaplayerfactory.cpp
@@ -91,6 +91,7 @@ QgsMapLayer *QgsMapLayerFactory::createLayer( const QString &uri, const QString
     {
       QgsMeshLayer::LayerOptions meshOptions;
       meshOptions.transformContext = options.transformContext;
+      meshOptions.loadDefaultStyle = options.loadDefaultStyle;
       return new QgsMeshLayer( uri, name, provider, meshOptions );
     }