introduce DataType for mesh dataset data definition and small fixes

Author: PeterPetrik

python/core/auto_generated/mesh/qgsmeshdataprovider.sip.in

@@ -140,6 +140,13 @@ such as whether the data is vector or scalar, name
 #include "qgsmeshdataprovider.h"
 %End
   public:
+
+    enum DataType
+    {
+      DataOnFaces,
+      DataOnVertices
+    };
+
     QgsMeshDatasetGroupMetadata();
 %Docstring
 Constructs an empty metadata object
@@ -178,14 +185,9 @@ Returns whether dataset group has vector data
 Returns whether dataset group has scalar data
 %End
 
-    bool isOnVertices() const;
-%Docstring
-Returns whether dataset group data is defined on vertices
-%End
-
-    bool isOnFaces() const;
+    DataType dataType() const;
 %Docstring
-Returns whether dataset group data is defined on faces
+Returns whether dataset group data is defined on vertices or faces
 %End
 
 };

python/core/auto_generated/mesh/qgsmeshlayer.sip.in

@@ -195,22 +195,33 @@ Returns active vector dataset
 %Docstring
 Interpolates the value on the given point from given dataset.
 
-Returns NaN for NaN values, for values outside range or when
-triangular mesh is not yet initialized on given point
+.. note::
+
+   It uses previously cached and indexed triangular mesh
+   and so if the layer has not been rendered previously
+   (e.g. when used in a script) it returns NaN value
+
+:param index: dataset index specifying group and dataset to extract value from
+:param point: point to query in map coordinates
+
+:return: interpolated value at the point. Returns NaN values for values
+         outside the mesh layer, nodata values and in case triangular mesh was not
+         previously used for rendering
+
 
 .. versionadded:: 3.4
 %End
 
   signals:
 
-    void activeScalarDatasetChanged( QgsMeshDatasetIndex index );
+    void activeScalarDatasetChanged( const QgsMeshDatasetIndex &index );
 %Docstring
 Emitted when active scalar dataset is changed
 
 .. versionadded:: 3.4
 %End
 
-    void activeVectorDatasetChanged( QgsMeshDatasetIndex index );
+    void activeVectorDatasetChanged( const QgsMeshDatasetIndex &index );
 %Docstring
 Emitted when active vector dataset is changed
 

src/app/mesh/qgsmeshrendereractivedatasetwidget.cpp

@@ -126,8 +126,8 @@ void QgsMeshRendererActiveDatasetWidget::updateMetadata( QgsMeshDatasetIndex dat
 
     const QgsMeshDatasetGroupMetadata gmeta = mMeshLayer->dataProvider()->datasetGroupMetadata( datasetIndex );
     msg += QStringLiteral( "<tr><td>%1</td><td>%2</td></tr>" )
-           .arg( tr( "Is on vertices" ) )
-           .arg( gmeta.isOnVertices() ? tr( "Yes" ) : tr( "No" ) );
+           .arg( tr( "Data Type" ) )
+           .arg( gmeta.dataType() == QgsMeshDatasetGroupMetadata::DataOnVertices ? tr( "Defined on vertices" ) : tr( "Defined on faces" ) );
 
     msg += QStringLiteral( "<tr><td>%1</td><td>%2</td></tr>" )
            .arg( tr( "Is vector" ) )

src/app/mesh/qgsmeshrendererscalarsettingswidget.cpp

@@ -112,7 +112,7 @@ void QgsMeshRendererScalarSettingsWidget::calcMinMax( QgsMeshDatasetIndex datase
     return;
 
   const QgsMeshDatasetGroupMetadata metadata = mMeshLayer->dataProvider()->datasetGroupMetadata( datasetIndex );
-  bool scalarDataOnVertices = metadata.isOnVertices();
+  bool scalarDataOnVertices = metadata.dataType() == QgsMeshDatasetGroupMetadata::DataOnVertices;
   int count;
   if ( scalarDataOnVertices )
     count = mMeshLayer->dataProvider()->vertexCount();

src/core/mesh/qgsmeshdataprovider.cpp

@@ -161,20 +161,16 @@ bool QgsMeshDatasetGroupMetadata::isScalar() const
   return mIsScalar;
 }
 
-QString QgsMeshDatasetGroupMetadata::name() const
-{
-  return mName;
-}
 
 
-bool QgsMeshDatasetGroupMetadata::isOnVertices() const
+QString QgsMeshDatasetGroupMetadata::name() const
 {
-  return mIsOnVertices;
+  return mName;
 }
 
-bool QgsMeshDatasetGroupMetadata::isOnFaces() const
+QgsMeshDatasetGroupMetadata::DataType QgsMeshDatasetGroupMetadata::dataType() const
 {
-  return !mIsOnVertices;
+  return ( mIsOnVertices ) ? DataType::DataOnVertices : DataType::DataOnFaces;
 }
 
 int QgsMeshDatasetSourceInterface::datasetCount( QgsMeshDatasetIndex index ) const

src/core/mesh/qgsmeshdataprovider.h

@@ -127,6 +127,14 @@ class CORE_EXPORT QgsMeshDatasetValue
 class CORE_EXPORT QgsMeshDatasetGroupMetadata
 {
   public:
+
+    //! Location of where data is specified for datasets in the dataset group
+    enum DataType
+    {
+      DataOnFaces, //!< Data is defined on faces
+      DataOnVertices //!< Data is defined on vertices
+    };
+
     //! Constructs an empty metadata object
     QgsMeshDatasetGroupMetadata() = default;
 
@@ -164,14 +172,9 @@ class CORE_EXPORT QgsMeshDatasetGroupMetadata
     bool isScalar() const;
 
     /**
-     * \brief Returns whether dataset group data is defined on vertices
-     */
-    bool isOnVertices() const;
-
-    /**
-     * \brief Returns whether dataset group data is defined on faces
+     * \brief Returns whether dataset group data is defined on vertices or faces
      */
-    bool isOnFaces() const;
+    DataType dataType() const;
 
   private:
     QString mName;

src/core/mesh/qgsmeshlayer.cpp

@@ -189,18 +189,17 @@ QgsMeshDatasetValue QgsMeshLayer::datasetValue( const QgsMeshDatasetIndex &index
 
   if ( mTriangularMesh && dataProvider() && dataProvider()->isValid() && index.isValid() )
   {
-    int face_index = mTriangularMesh->faceIndexForPoint( point ) ;
-    if ( face_index >= 0 )
+    int faceIndex = mTriangularMesh->faceIndexForPoint( point ) ;
+    if ( faceIndex >= 0 )
     {
-      bool isOnFaces = dataProvider()->datasetGroupMetadata( index ).isOnFaces();
-      if ( isOnFaces )
+      if ( dataProvider()->datasetGroupMetadata( index ).dataType() == QgsMeshDatasetGroupMetadata::DataOnFaces )
       {
-        int nativeFaceIndex = mTriangularMesh->trianglesToNativeFaces().at( face_index );
+        int nativeFaceIndex = mTriangularMesh->trianglesToNativeFaces().at( faceIndex );
         return dataProvider()->datasetValue( index, nativeFaceIndex );
       }
       else
       {
-        const QgsMeshFace &face = mTriangularMesh->triangles()[face_index];
+        const QgsMeshFace &face = mTriangularMesh->triangles()[faceIndex];
         const int v1 = face[0], v2 = face[1], v3 = face[2];
         const QgsPoint p1 = mTriangularMesh->vertices()[v1], p2 = mTriangularMesh->vertices()[v2], p3 = mTriangularMesh->vertices()[v3];
         const QgsMeshDatasetValue val1 = dataProvider()->datasetValue( index, v1 );

src/core/mesh/qgsmeshlayer.h

@@ -186,8 +186,15 @@ class CORE_EXPORT QgsMeshLayer : public QgsMapLayer
     /**
       * Interpolates the value on the given point from given dataset.
       *
-      * Returns NaN for NaN values, for values outside range or when
-      * triangular mesh is not yet initialized on given point
+      * \note It uses previously cached and indexed triangular mesh
+      * and so if the layer has not been rendered previously
+      * (e.g. when used in a script) it returns NaN value
+      *
+      * \param index dataset index specifying group and dataset to extract value from
+      * \param point point to query in map coordinates
+      * \returns interpolated value at the point. Returns NaN values for values
+      * outside the mesh layer, nodata values and in case triangular mesh was not
+      * previously used for rendering
       *
       * \since QGIS 3.4
       */
@@ -200,14 +207,14 @@ class CORE_EXPORT QgsMeshLayer : public QgsMapLayer
      *
      * \since QGIS 3.4
      */
-    void activeScalarDatasetChanged( QgsMeshDatasetIndex index );
+    void activeScalarDatasetChanged( const QgsMeshDatasetIndex &index );
 
     /**
      * Emitted when active vector dataset is changed
      *
      * \since QGIS 3.4
      */
-    void activeVectorDatasetChanged( QgsMeshDatasetIndex index );
+    void activeVectorDatasetChanged( const QgsMeshDatasetIndex &index );
 
   private: // Private methods
 

src/core/mesh/qgsmeshlayerrenderer.cpp

@@ -140,7 +140,7 @@ void QgsMeshLayerRenderer::copyScalarDatasetValues( QgsMeshLayer *layer )
   if ( datasetIndex.isValid() )
   {
     const QgsMeshDatasetGroupMetadata metadata = layer->dataProvider()->datasetGroupMetadata( datasetIndex );
-    mScalarDataOnVertices = metadata.isOnVertices();
+    mScalarDataOnVertices = metadata.dataType() == QgsMeshDatasetGroupMetadata::DataOnVertices;
     int count;
     if ( mScalarDataOnVertices )
       count = mNativeMesh.vertices.count();
@@ -172,7 +172,7 @@ void QgsMeshLayerRenderer::copyVectorDatasetValues( QgsMeshLayer *layer )
     }
     else
     {
-      mVectorDataOnVertices = metadata.isOnVertices();
+      mVectorDataOnVertices = metadata.dataType() == QgsMeshDatasetGroupMetadata::DataOnVertices;
       int count;
       if ( mVectorDataOnVertices )
         count = mNativeMesh.vertices.count();

src/core/mesh/qgstriangularmesh.cpp

@@ -180,8 +180,8 @@ const QVector<int> &QgsTriangularMesh::trianglesToNativeFaces() const
 
 int QgsTriangularMesh::faceIndexForPoint( const QgsPointXY &point ) const
 {
-  const QList<QgsFeatureId> face_indexes = mSpatialIndex.intersects( QgsRectangle( point, point ) );
-  for ( QgsFeatureId fid : face_indexes )
+  const QList<QgsFeatureId> faceIndexes = mSpatialIndex.intersects( QgsRectangle( point, point ) );
+  for ( const QgsFeatureId fid : faceIndexes )
   {
     int faceIndex = static_cast<int>( fid );
     const QgsMeshFace &face = mTriangularMesh.faces.at( faceIndex );