Generation of legend items for mesh layers

Author: wonder-sk

python/core/auto_generated/qgsmaplayerlegend.sip.in

@@ -61,6 +61,11 @@ Create new legend implementation for vector layer
     static QgsMapLayerLegend *defaultRasterLegend( QgsRasterLayer *rl ) /Factory/;
 %Docstring
 Create new legend implementation for raster layer
+%End
+
+    static QgsMapLayerLegend *defaultMeshLegend( QgsMeshLayer *ml ) /Factory/;
+%Docstring
+Create new legend implementation for mesh layer
 %End
 
   signals:
@@ -192,6 +197,26 @@ Default legend implementation for raster layers
 };
 
 
+class QgsDefaultMeshLayerLegend : QgsMapLayerLegend
+{
+%Docstring
+Default legend implementation for mesh layers
+
+.. versionadded:: 3.4
+%End
+
+%TypeHeaderCode
+#include "qgsmaplayerlegend.h"
+%End
+  public:
+    explicit QgsDefaultMeshLayerLegend( QgsMeshLayer *ml );
+
+    virtual QList<QgsLayerTreeModelLegendNode *> createLayerTreeModelLegendNodes( QgsLayerTreeLayer *nodeLayer ) /Factory/;
+
+
+};
+
+
 /************************************************************************
  * This file has been generated automatically from                      *
  *                                                                      *

src/core/mesh/qgsmeshlayer.cpp

@@ -22,6 +22,7 @@
 
 
 #include "qgslogger.h"
+#include "qgsmaplayerlegend.h"
 #include "qgsmeshdataprovider.h"
 #include "qgsmeshlayer.h"
 #include "qgsmeshlayerrenderer.h"
@@ -41,6 +42,8 @@ QgsMeshLayer::QgsMeshLayer( const QString &meshLayerPath,
   QgsDataProvider::ProviderOptions providerOptions;
   setDataProvider( providerKey, providerOptions );
 
+  setLegend( QgsMapLayerLegend::defaultMeshLegend( this ) );
+
   // show at least the mesh by default so we render something
   mRendererNativeMeshSettings.setEnabled( true );
 
@@ -107,6 +110,7 @@ QgsMeshRendererMeshSettings QgsMeshLayer::rendererNativeMeshSettings() const
 void QgsMeshLayer::setRendererNativeMeshSettings( const QgsMeshRendererMeshSettings &settings )
 {
   mRendererNativeMeshSettings = settings;
+  emit rendererChanged();
   triggerRepaint();
 }
 
@@ -118,6 +122,7 @@ QgsMeshRendererMeshSettings QgsMeshLayer::rendererTriangularMeshSettings() const
 void QgsMeshLayer::setRendererTriangularMeshSettings( const QgsMeshRendererMeshSettings &settings )
 {
   mRendererTriangularMeshSettings = settings;
+  emit rendererChanged();
   triggerRepaint();
 }
 
@@ -129,6 +134,7 @@ QgsMeshRendererScalarSettings QgsMeshLayer::rendererScalarSettings() const
 void QgsMeshLayer::setRendererScalarSettings( const QgsMeshRendererScalarSettings &settings )
 {
   mRendererScalarSettings = settings;
+  emit rendererChanged();
   triggerRepaint();
 }
 
@@ -141,6 +147,7 @@ QgsMeshRendererVectorSettings QgsMeshLayer::rendererVectorSettings() const
 void QgsMeshLayer::setRendererVectorSettings( const QgsMeshRendererVectorSettings &settings )
 {
   mRendererVectorSettings = settings;
+  emit rendererChanged();
   triggerRepaint();
 }
 
@@ -155,6 +162,7 @@ void QgsMeshLayer::setActiveScalarDataset( QgsMeshDatasetIndex index )
   else
     mActiveScalarDataset = QgsMeshDatasetIndex();
 
+  emit rendererChanged();
   triggerRepaint();
 
   emit activeScalarDatasetChanged( mActiveScalarDataset );
@@ -178,6 +186,7 @@ void QgsMeshLayer::setActiveVectorDataset( QgsMeshDatasetIndex index )
       mActiveVectorDataset = QgsMeshDatasetIndex();
   }
 
+  emit rendererChanged();
   triggerRepaint();
 
   emit activeVectorDatasetChanged( mActiveVectorDataset );

src/core/qgsmaplayerlegend.cpp

@@ -18,6 +18,7 @@
 #include "qgssettings.h"
 #include "qgslayertree.h"
 #include "qgslayertreemodellegendnode.h"
+#include "qgsmeshlayer.h"
 #include "qgspluginlayer.h"
 #include "qgsrasterlayer.h"
 #include "qgsrenderer.h"
@@ -53,6 +54,11 @@ QgsMapLayerLegend *QgsMapLayerLegend::defaultRasterLegend( QgsRasterLayer *rl )
   return new QgsDefaultRasterLayerLegend( rl );
 }
 
+QgsMapLayerLegend *QgsMapLayerLegend::defaultMeshLegend( QgsMeshLayer *ml )
+{
+  return new QgsDefaultMeshLayerLegend( ml );
+}
+
 // -------------------------------------------------------------------------
 
 
@@ -330,3 +336,51 @@ QList<QgsLayerTreeModelLegendNode *> QgsDefaultRasterLayerLegend::createLayerTre
 
   return nodes;
 }
+
+// -------------------------------------------------------------------------
+
+QgsDefaultMeshLayerLegend::QgsDefaultMeshLayerLegend( QgsMeshLayer *ml )
+  : mLayer( ml )
+{
+  connect( mLayer, &QgsMapLayer::rendererChanged, this, &QgsMapLayerLegend::itemsChanged );
+}
+
+QList<QgsLayerTreeModelLegendNode *> QgsDefaultMeshLayerLegend::createLayerTreeModelLegendNodes( QgsLayerTreeLayer *nodeLayer )
+{
+  QList<QgsLayerTreeModelLegendNode *> nodes;
+
+  QgsMeshDataProvider *provider = mLayer->dataProvider();
+  if ( !provider )
+    return nodes;
+
+  QgsMeshDatasetIndex indexScalar = mLayer->activeScalarDataset();
+  QgsMeshDatasetIndex indexVector = mLayer->activeVectorDataset();
+
+  QString name;
+  if ( indexScalar.isValid() && indexVector.isValid() && indexScalar.group() != indexVector.group() )
+    name = QString( "%1 / %2" ).arg( provider->datasetGroupMetadata( indexScalar.group() ).name(), provider->datasetGroupMetadata( indexVector.group() ).name() );
+  else if ( indexScalar.isValid() )
+    name = provider->datasetGroupMetadata( indexScalar.group() ).name();
+  else if ( indexVector.isValid() )
+    name = provider->datasetGroupMetadata( indexVector.group() ).name();
+  else
+  {
+    // neither contours nor vectors get rendered - no legend needed
+    return nodes;
+  }
+
+  nodes << new QgsSimpleLegendNode( nodeLayer, name );
+
+  QgsMeshRendererScalarSettings settings = mLayer->rendererScalarSettings();
+  if ( settings.isEnabled() )
+  {
+    QgsLegendColorList items;
+    settings.colorRampShader().legendSymbologyItems( items );
+    for ( const QPair< QString, QColor > &item : qgis::as_const( items ) )
+    {
+      nodes << new QgsRasterSymbolLegendNode( nodeLayer, item.second, item.first );
+    }
+  }
+
+  return nodes;
+}

src/core/qgsmaplayerlegend.h

@@ -24,6 +24,7 @@ class QDomElement;
 
 class QgsLayerTreeLayer;
 class QgsLayerTreeModelLegendNode;
+class QgsMeshLayer;
 class QgsPluginLayer;
 class QgsRasterLayer;
 class QgsReadWriteContext;
@@ -75,6 +76,9 @@ class CORE_EXPORT QgsMapLayerLegend : public QObject
     //! Create new legend implementation for raster layer
     static QgsMapLayerLegend *defaultRasterLegend( QgsRasterLayer *rl ) SIP_FACTORY;
 
+    //! Create new legend implementation for mesh layer
+    static QgsMapLayerLegend *defaultMeshLegend( QgsMeshLayer *ml ) SIP_FACTORY;
+
   signals:
     //! Emitted when existing items/nodes got invalid and should be replaced by new ones
     void itemsChanged();
@@ -194,4 +198,23 @@ class CORE_EXPORT QgsDefaultRasterLayerLegend : public QgsMapLayerLegend
 };
 
 
+/**
+ * \ingroup core
+ * Default legend implementation for mesh layers
+ * \since QGIS 3.4
+ */
+class CORE_EXPORT QgsDefaultMeshLayerLegend : public QgsMapLayerLegend
+{
+    Q_OBJECT
+
+  public:
+    explicit QgsDefaultMeshLayerLegend( QgsMeshLayer *ml );
+
+    QList<QgsLayerTreeModelLegendNode *> createLayerTreeModelLegendNodes( QgsLayerTreeLayer *nodeLayer ) SIP_FACTORY override;
+
+  private:
+    QgsMeshLayer *mLayer = nullptr;
+};
+
+
 #endif // QGSMAPLAYERLEGEND_H

tests/src/core/testqgsmeshlayerrenderer.cpp

@@ -29,6 +29,7 @@
 #include "qgsmaplayer.h"
 #include "qgsmeshlayer.h"
 #include "qgsapplication.h"
+#include "qgsmaplayerlegend.h"
 #include "qgsproviderregistry.h"
 #include "qgsproject.h"
 #include "qgsmaprenderersequentialjob.h"
@@ -69,6 +70,8 @@ class TestQgsMeshRenderer : public QObject
     void test_vertex_vector_dataset_rendering();
     void test_face_scalar_dataset_rendering();
     void test_face_vector_dataset_rendering();
+
+    void test_signals();
 };
 
 void TestQgsMeshRenderer::init()
@@ -194,5 +197,20 @@ void TestQgsMeshRenderer::test_face_vector_dataset_rendering()
   QVERIFY( imageCheck( "quad_and_triangle_face_vector_dataset" ) );
 }
 
+void TestQgsMeshRenderer::test_signals()
+{
+  mMemoryLayer->setActiveScalarDataset( QgsMeshDatasetIndex( 0, 0 ) );
+
+  QSignalSpy spy1( mMemoryLayer, &QgsMapLayer::rendererChanged );
+  QSignalSpy spy2( mMemoryLayer->legend(), &QgsMapLayerLegend::itemsChanged );
+  QSignalSpy spy3( mMemoryLayer, &QgsMapLayer::legendChanged );
+
+  mMemoryLayer->setActiveScalarDataset( QgsMeshDatasetIndex( 1, 0 ) );
+
+  QCOMPARE( spy1.count(), 1 );
+  QCOMPARE( spy2.count(), 1 );
+  QCOMPARE( spy3.count(), 1 );
+}
+
 QGSTEST_MAIN( TestQgsMeshRenderer )
 #include "testqgsmeshlayerrenderer.moc"