[mesh] use MDAL 0.1.0 API in QGIS. Allows lazy loading of formats and…

… effective transfer of data introduce MeshDataBlock use mesh block in rendering calculate magnitude use new mesh API fix bug for memory layer fix SIP, sip is unable to work with qvector<qgsmeshvertex> fix tests implement new MDAL min/max api improve mesh documentation fix travis build
qgis · Dec 7, 2018 · 2807172 · 2807172
1 parent d43f637
commit 2807172
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Showing 19 changed files with 834 additions and 313 deletions.
diff --git a/python/core/auto_generated/mesh/qgsmeshdataprovider.sip.in b/python/core/auto_generated/mesh/qgsmeshdataprovider.sip.in
@@ -53,6 +53,28 @@ typedef QgsPoint QgsMeshVertex;
 
 typedef QVector<int> QgsMeshFace;
 
+struct QgsMesh
+{
+  int vertexCount() const;
+%Docstring
+Returns number of vertices
+%End
+  int faceCount() const;
+%Docstring
+Returns number of faces
+%End
+
+  QgsMeshVertex vertex( int index ) const;
+%Docstring
+Returns a vertex at the index
+%End
+  QgsMeshFace face( int index ) const;
+%Docstring
+Returns a face at the index
+%End
+
+};
+
 class QgsMeshDatasetValue
 {
 %Docstring
@@ -122,6 +144,76 @@ Returns y value
 
     bool operator==( const QgsMeshDatasetValue &other ) const;
 
+};
+
+class QgsMeshDataBlock
+{
+%Docstring
+
+QgsMeshDataBlock is a block that can be used to retrieve a block of
+active flag (e.g. face's active integer flag)
+scalars (e.g. scalar dataset double values)
+vectors (e.g. vector dataset doubles x,y values)
+
+data are implicitly shared, so the class can be quickly copied
+std.numeric_limits<double>.quiet_NaN() represents NODATA value
+
+Data can be accessed all at once with buffer() (faster) or
+value by value (slower) with active() or value()
+
+.. versionadded:: 3.6
+%End
+
+%TypeHeaderCode
+#include "qgsmeshdataprovider.h"
+%End
+  public:
+    enum DataType
+    {
+      ActiveFlagInteger,
+      ScalarDouble,
+      Vector2DDouble,
+    };
+
+    QgsMeshDataBlock();
+%Docstring
+Constructs an invalid block
+%End
+
+    QgsMeshDataBlock( DataType type, int count );
+%Docstring
+Constructs a new block
+%End
+
+    DataType type() const;
+%Docstring
+Type of data stored in the block
+%End
+
+    int count() const;
+%Docstring
+Number of items stored in the block
+%End
+
+    bool isValid() const;
+%Docstring
+Whether the block is valid
+%End
+
+    QgsMeshDatasetValue value( int index ) const;
+%Docstring
+Returns a value represented by the index
+For active flag the behavior is undefined
+%End
+
+    bool active( int index ) const;
+%Docstring
+Returns a value for active flag by the index
+For scalar and vector 2d the behavior is undefined
+%End
+
+
+
 };
 
 class QgsMeshDatasetGroupMetadata
@@ -157,13 +249,17 @@ Constructs an empty metadata object
     QgsMeshDatasetGroupMetadata( const QString &name,
                                  bool isScalar,
                                  bool isOnVertices,
+                                 double minimum,
+                                 double maximum,
                                  const QMap<QString, QString> &extraOptions );
 %Docstring
 Constructs a valid metadata object
 
 :param name: name of the dataset group
 :param isScalar: dataset contains scalar data, specifically the y-value of QgsMeshDatasetValue is NaN
 :param isOnVertices: dataset values are defined on mesh's vertices. If false, values are defined on faces.
+:param minimum: minimum value (magnitude for vectors) present among all group's dataset values
+:param maximum: maximum value (magnitude for vectors) present among all group's dataset values
 :param extraOptions: dataset's extra options stored by the provider. Usually contains the name, time value, time units, data file vendor, ...
 %End
 
@@ -190,6 +286,16 @@ Returns whether dataset group has scalar data
     DataType dataType() const;
 %Docstring
 Returns whether dataset group data is defined on vertices or faces
+%End
+
+    double minimum() const;
+%Docstring
+Returns minimum scalar value/vector magnitude present for whole dataset group
+%End
+
+    double maximum() const;
+%Docstring
+Returns maximum scalar value/vector magnitude present for whole dataset group
 %End
 
 };
@@ -218,7 +324,10 @@ Constructs an empty metadata object
 %End
 
     QgsMeshDatasetMetadata( double time,
-                            bool isValid );
+                            bool isValid,
+                            double minimum,
+                            double maximum
+                          );
 %Docstring
 Constructs a valid metadata object
 
@@ -234,6 +343,16 @@ Returns the time value for this dataset
     bool isValid() const;
 %Docstring
 Returns whether dataset is valid
+%End
+
+    double minimum() const;
+%Docstring
+Returns minimum scalar value/vector magnitude present for the dataset
+%End
+
+    double maximum() const;
+%Docstring
+Returns maximum scalar value/vector magnitude present for the dataset
 %End
 
 };
@@ -278,14 +397,11 @@ Returns number of faces in the native mesh
 :return: Number of faces in the mesh
 %End
 
-    virtual QgsMeshVertex vertex( int index ) const = 0;
+    virtual void populateMesh( QgsMesh *mesh ) const = 0;
 %Docstring
-Returns the mesh vertex at index
-%End
+Populates the mesh vertices and faces
 
-    virtual QgsMeshFace face( int index ) const = 0;
-%Docstring
-Returns the mesh face at index
+.. versionadded:: 3.6
 %End
 };
 
@@ -359,8 +475,19 @@ Returns dataset metadata
     virtual QgsMeshDatasetValue datasetValue( QgsMeshDatasetIndex index, int valueIndex ) const = 0;
 %Docstring
 Returns vector/scalar value associated with the index from the dataset
+To read multiple continuous values, use :py:func:`QgsMeshDatasetSourceInterface.datasetValues()`
+
+See QgsMeshDatasetMetadata.isVector() or :py:func:`QgsMeshDataBlock.type()`
+to check if the returned value is vector or scalar
+%End
+
+    virtual QgsMeshDataBlock datasetValues( QgsMeshDatasetIndex index, int valueIndex, int count ) const = 0;
+%Docstring
+Returns N vector/scalar values from the index from the dataset
 
 See QgsMeshDatasetMetadata.isVector() to check if the returned value is vector or scalar
+
+.. versionadded:: 3.6
 %End
 
     virtual bool isFaceActive( QgsMeshDatasetIndex index, int faceIndex ) const = 0;
@@ -373,6 +500,13 @@ set active flag for F2 to false.
 V1 ---- V2 ---- V5-----V7
 |   F1  |   F2   | F3  |
 V3 ---- V4 ---- V6-----V8
+%End
+
+    virtual QgsMeshDataBlock areFacesActive( QgsMeshDatasetIndex index, int faceIndex, int count ) const = 0;
+%Docstring
+Returns whether the faces are active for particular dataset
+
+.. versionadded:: 3.6
 %End
 };
 
@@ -398,14 +532,6 @@ Responsible for reading native mesh data
     QgsMeshDataProvider( const QString &uri, const QgsDataProvider::ProviderOptions &options );
 %Docstring
 Ctor
-%End
-
-    virtual QgsRectangle extent() const;
-
-%Docstring
-Returns the extent of the layer
-
-:return: QgsRectangle containing the extent of the layer
 %End
 
   signals:

diff --git a/src/app/mesh/qgsmeshrendererscalarsettingswidget.cpp b/src/app/mesh/qgsmeshrendererscalarsettingswidget.cpp
@@ -93,8 +93,9 @@ void QgsMeshRendererScalarSettingsWidget::minMaxEdited()
 
 void QgsMeshRendererScalarSettingsWidget::recalculateMinMaxButtonClicked()
 {
-  double min, max;
-  QgsMeshLayerUtils::calculateMinMaxForDatasetGroup( min, max, mMeshLayer->dataProvider(), mActiveDatasetGroup );
+  const QgsMeshDatasetGroupMetadata metadata = mMeshLayer->dataProvider()->datasetGroupMetadata( mActiveDatasetGroup );
+  double min = metadata.minimum();
+  double max = metadata.maximum();
   whileBlocking( mScalarMinLineEdit )->setText( QString::number( min ) );
   whileBlocking( mScalarMaxLineEdit )->setText( QString::number( max ) );
   mScalarColorRampShaderWidget->setMinimumMaximumAndClassify( min, max );