Show a color ramp legend for vector heatmap layers

python/PyQt6/core/auto_generated/symbology/qgsheatmaprenderer.sip.in

@@ -60,6 +60,8 @@ Creates a new heatmap renderer instance from XML
     static QgsHeatmapRenderer *convertFromRenderer( const QgsFeatureRenderer *renderer ) /Factory/;
     virtual bool accept( QgsStyleEntityVisitorInterface *visitor ) const;
 
+    virtual QList<QgsLayerTreeModelLegendNode *> createLegendNodes( QgsLayerTreeLayer *nodeLayer ) const /Factory/;
+
 
     virtual void modifyRequestExtent( QgsRectangle &extent, QgsRenderContext &context );
 
@@ -81,6 +83,24 @@ Sets the color ramp to use for shading the heatmap.
 :param ramp: color ramp for heatmap. Ownership of ramp is transferred to the renderer.
 
 .. seealso:: :py:func:`colorRamp`
+%End
+
+    const QgsColorRampLegendNodeSettings &legendSettings() const;
+%Docstring
+Returns the color ramp legend settings.
+
+.. seealso:: :py:func:`setLegendSettings`
+
+.. versionadded:: 3.38
+%End
+
+    void setLegendSettings( const QgsColorRampLegendNodeSettings &settings );
+%Docstring
+Sets the color ramp legend ``settings``.
+
+.. seealso:: :py:func:`legendSettings`
+
+.. versionadded:: 3.38
 %End
 
     double radius() const;

python/PyQt6/core/auto_generated/symbology/qgsrenderer.sip.in

@@ -358,7 +358,22 @@ the features displayed using that key.
 %Docstring
 Returns a list of symbology items for the legend
 
+.. seealso:: :py:func:`createLegendNodes`
+
 .. seealso:: :py:func:`legendKeys`
+%End
+
+    virtual QList<QgsLayerTreeModelLegendNode *> createLegendNodes( QgsLayerTreeLayer *nodeLayer ) const /Factory/;
+%Docstring
+Returns a list of legend nodes to be used for the legend for the renderer.
+
+Ownership is transferred to the caller.
+
+The default implementation creates a legend node for each symbol item returned by :py:func:`~QgsFeatureRenderer.legendSymbolItems`
+
+.. seealso:: :py:func:`legendSymbolItems`
+
+.. versionadded:: 3.38
 %End
 
     virtual QString legendClassificationAttribute() const;

python/PyQt6/gui/auto_additions/qgscolorramplegendnodewidget.py

@@ -0,0 +1,14 @@
+# The following has been generated automatically from src/gui/qgscolorramplegendnodewidget.h
+# monkey patching scoped based enum
+QgsColorRampLegendNodeWidget.Capability.Prefix.__doc__ = "Allow editing legend prefix"
+QgsColorRampLegendNodeWidget.Capability.Suffix.__doc__ = "Allow editing legend suffix"
+QgsColorRampLegendNodeWidget.Capability.NumberFormat.__doc__ = "Allow editing number format"
+QgsColorRampLegendNodeWidget.Capability.DefaultMinimum.__doc__ = "Allow resetting minimum label to default"
+QgsColorRampLegendNodeWidget.Capability.DefaultMaximum.__doc__ = "Allow resetting maximum label to default"
+QgsColorRampLegendNodeWidget.Capability.AllCapabilities.__doc__ = "All capabilities"
+QgsColorRampLegendNodeWidget.Capability.__doc__ = "Capabilities to expose in the widget.\n\n.. versionadded:: 3.38\n\n" + '* ``Prefix``: ' + QgsColorRampLegendNodeWidget.Capability.Prefix.__doc__ + '\n' + '* ``Suffix``: ' + QgsColorRampLegendNodeWidget.Capability.Suffix.__doc__ + '\n' + '* ``NumberFormat``: ' + QgsColorRampLegendNodeWidget.Capability.NumberFormat.__doc__ + '\n' + '* ``DefaultMinimum``: ' + QgsColorRampLegendNodeWidget.Capability.DefaultMinimum.__doc__ + '\n' + '* ``DefaultMaximum``: ' + QgsColorRampLegendNodeWidget.Capability.DefaultMaximum.__doc__ + '\n' + '* ``AllCapabilities``: ' + QgsColorRampLegendNodeWidget.Capability.AllCapabilities.__doc__
+# --
+QgsColorRampLegendNodeWidget.Capability.baseClass = QgsColorRampLegendNodeWidget
+QgsColorRampLegendNodeWidget.Capabilities = lambda flags=0: QgsColorRampLegendNodeWidget.Capability(flags)
+QgsColorRampLegendNodeWidget.Capabilities.baseClass = QgsColorRampLegendNodeWidget
+Capabilities = QgsColorRampLegendNodeWidget  # dirty hack since SIP seems to introduce the flags in module

python/PyQt6/gui/auto_generated/qgscolorramplegendnodewidget.sip.in

@@ -11,7 +11,6 @@
 
 
 
-
 class QgsColorRampLegendNodeWidget: QgsPanelWidget
 {
 %Docstring(signature="appended")
@@ -30,9 +29,24 @@ When changes are made the to settings by a user the :py:func:`~widgetChanged` si
 %End
   public:
 
-    QgsColorRampLegendNodeWidget( QWidget *parent = 0 );
+    enum class Capability /BaseType=IntFlag/
+    {
+      Prefix,
+      Suffix,
+      NumberFormat,
+      DefaultMinimum,
+      DefaultMaximum,
+      AllCapabilities,
+    };
+
+    typedef QFlags<QgsColorRampLegendNodeWidget::Capability> Capabilities;
+
+
+    QgsColorRampLegendNodeWidget( QWidget *parent = 0, QgsColorRampLegendNodeWidget::Capabilities capabilities = QgsColorRampLegendNodeWidget::Capability::AllCapabilities );
 %Docstring
 Constructor for QgsColorRampLegendNodeWidget, with the specified ``parent`` widget.
+
+Since QGIS 3.38, the ``capabilities`` argument can be used to fine-tune settings exposed in the widget.
 %End
 
     QgsColorRampLegendNodeSettings settings() const;
@@ -59,6 +73,8 @@ when using single band gray renderer).
 %End
 
 };
+QFlags<QgsColorRampLegendNodeWidget::Capability> operator|(QgsColorRampLegendNodeWidget::Capability f1, QFlags<QgsColorRampLegendNodeWidget::Capability> f2);
+
 
 class QgsColorRampLegendNodeDialog : QDialog
 {
@@ -73,9 +89,11 @@ A dialog for configuring a :py:class:`QgsColorRampLegendNode` (:py:class:`QgsCol
 %End
   public:
 
-    QgsColorRampLegendNodeDialog( const QgsColorRampLegendNodeSettings &settings, QWidget *parent /TransferThis/ = 0 );
+    QgsColorRampLegendNodeDialog( const QgsColorRampLegendNodeSettings &settings, QWidget *parent /TransferThis/ = 0, QgsColorRampLegendNodeWidget::Capabilities capabilities = QgsColorRampLegendNodeWidget::Capability::AllCapabilities );
 %Docstring
 Constructor for QgsColorRampLegendNodeDialog, initially showing the specified ``settings``.
+
+Since QGIS 3.38, the ``capabilities`` argument can be used to fine-tune settings exposed in the dialog.
 %End
 
     QgsColorRampLegendNodeSettings settings() const;

python/core/auto_generated/symbology/qgsheatmaprenderer.sip.in

@@ -60,6 +60,8 @@ Creates a new heatmap renderer instance from XML
     static QgsHeatmapRenderer *convertFromRenderer( const QgsFeatureRenderer *renderer ) /Factory/;
     virtual bool accept( QgsStyleEntityVisitorInterface *visitor ) const;
 
+    virtual QList<QgsLayerTreeModelLegendNode *> createLegendNodes( QgsLayerTreeLayer *nodeLayer ) const /Factory/;
+
 
     virtual void modifyRequestExtent( QgsRectangle &extent, QgsRenderContext &context );
 
@@ -81,6 +83,24 @@ Sets the color ramp to use for shading the heatmap.
 :param ramp: color ramp for heatmap. Ownership of ramp is transferred to the renderer.
 
 .. seealso:: :py:func:`colorRamp`
+%End
+
+    const QgsColorRampLegendNodeSettings &legendSettings() const;
+%Docstring
+Returns the color ramp legend settings.
+
+.. seealso:: :py:func:`setLegendSettings`
+
+.. versionadded:: 3.38
+%End
+
+    void setLegendSettings( const QgsColorRampLegendNodeSettings &settings );
+%Docstring
+Sets the color ramp legend ``settings``.
+
+.. seealso:: :py:func:`legendSettings`
+
+.. versionadded:: 3.38
 %End
 
     double radius() const;

python/core/auto_generated/symbology/qgsrenderer.sip.in

@@ -358,7 +358,22 @@ the features displayed using that key.
 %Docstring
 Returns a list of symbology items for the legend
 
+.. seealso:: :py:func:`createLegendNodes`
+
 .. seealso:: :py:func:`legendKeys`
+%End
+
+    virtual QList<QgsLayerTreeModelLegendNode *> createLegendNodes( QgsLayerTreeLayer *nodeLayer ) const /Factory/;
+%Docstring
+Returns a list of legend nodes to be used for the legend for the renderer.
+
+Ownership is transferred to the caller.
+
+The default implementation creates a legend node for each symbol item returned by :py:func:`~QgsFeatureRenderer.legendSymbolItems`
+
+.. seealso:: :py:func:`legendSymbolItems`
+
+.. versionadded:: 3.38
 %End
 
     virtual QString legendClassificationAttribute() const;

python/gui/auto_additions/qgscolorramplegendnodewidget.py

@@ -0,0 +1,13 @@
+# The following has been generated automatically from src/gui/qgscolorramplegendnodewidget.h
+# monkey patching scoped based enum
+QgsColorRampLegendNodeWidget.Capability.Prefix.__doc__ = "Allow editing legend prefix"
+QgsColorRampLegendNodeWidget.Capability.Suffix.__doc__ = "Allow editing legend suffix"
+QgsColorRampLegendNodeWidget.Capability.NumberFormat.__doc__ = "Allow editing number format"
+QgsColorRampLegendNodeWidget.Capability.DefaultMinimum.__doc__ = "Allow resetting minimum label to default"
+QgsColorRampLegendNodeWidget.Capability.DefaultMaximum.__doc__ = "Allow resetting maximum label to default"
+QgsColorRampLegendNodeWidget.Capability.AllCapabilities.__doc__ = "All capabilities"
+QgsColorRampLegendNodeWidget.Capability.__doc__ = "Capabilities to expose in the widget.\n\n.. versionadded:: 3.38\n\n" + '* ``Prefix``: ' + QgsColorRampLegendNodeWidget.Capability.Prefix.__doc__ + '\n' + '* ``Suffix``: ' + QgsColorRampLegendNodeWidget.Capability.Suffix.__doc__ + '\n' + '* ``NumberFormat``: ' + QgsColorRampLegendNodeWidget.Capability.NumberFormat.__doc__ + '\n' + '* ``DefaultMinimum``: ' + QgsColorRampLegendNodeWidget.Capability.DefaultMinimum.__doc__ + '\n' + '* ``DefaultMaximum``: ' + QgsColorRampLegendNodeWidget.Capability.DefaultMaximum.__doc__ + '\n' + '* ``AllCapabilities``: ' + QgsColorRampLegendNodeWidget.Capability.AllCapabilities.__doc__
+# --
+QgsColorRampLegendNodeWidget.Capability.baseClass = QgsColorRampLegendNodeWidget
+QgsColorRampLegendNodeWidget.Capabilities.baseClass = QgsColorRampLegendNodeWidget
+Capabilities = QgsColorRampLegendNodeWidget  # dirty hack since SIP seems to introduce the flags in module

python/gui/auto_generated/qgscolorramplegendnodewidget.sip.in

@@ -11,7 +11,6 @@
 
 
 
-
 class QgsColorRampLegendNodeWidget: QgsPanelWidget
 {
 %Docstring(signature="appended")
@@ -30,9 +29,24 @@ When changes are made the to settings by a user the :py:func:`~widgetChanged` si
 %End
   public:
 
-    QgsColorRampLegendNodeWidget( QWidget *parent = 0 );
+    enum class Capability
+    {
+      Prefix,
+      Suffix,
+      NumberFormat,
+      DefaultMinimum,
+      DefaultMaximum,
+      AllCapabilities,
+    };
+
+    typedef QFlags<QgsColorRampLegendNodeWidget::Capability> Capabilities;
+
+
+    QgsColorRampLegendNodeWidget( QWidget *parent = 0, QgsColorRampLegendNodeWidget::Capabilities capabilities = QgsColorRampLegendNodeWidget::Capability::AllCapabilities );
 %Docstring
 Constructor for QgsColorRampLegendNodeWidget, with the specified ``parent`` widget.
+
+Since QGIS 3.38, the ``capabilities`` argument can be used to fine-tune settings exposed in the widget.
 %End
 
     QgsColorRampLegendNodeSettings settings() const;
@@ -59,6 +73,8 @@ when using single band gray renderer).
 %End
 
 };
+QFlags<QgsColorRampLegendNodeWidget::Capability> operator|(QgsColorRampLegendNodeWidget::Capability f1, QFlags<QgsColorRampLegendNodeWidget::Capability> f2);
+
 
 class QgsColorRampLegendNodeDialog : QDialog
 {
@@ -73,9 +89,11 @@ A dialog for configuring a :py:class:`QgsColorRampLegendNode` (:py:class:`QgsCol
 %End
   public:
 
-    QgsColorRampLegendNodeDialog( const QgsColorRampLegendNodeSettings &settings, QWidget *parent /TransferThis/ = 0 );
+    QgsColorRampLegendNodeDialog( const QgsColorRampLegendNodeSettings &settings, QWidget *parent /TransferThis/ = 0, QgsColorRampLegendNodeWidget::Capabilities capabilities = QgsColorRampLegendNodeWidget::Capability::AllCapabilities );
 %Docstring
 Constructor for QgsColorRampLegendNodeDialog, initially showing the specified ``settings``.
+
+Since QGIS 3.38, the ``capabilities`` argument can be used to fine-tune settings exposed in the dialog.
 %End
 
     QgsColorRampLegendNodeSettings settings() const;

src/core/qgsmaplayerlegend.cpp

@@ -384,27 +384,24 @@ QList<QgsLayerTreeModelLegendNode *> QgsDefaultVectorLayerLegend::createLayerTre
     nodes.append( new QgsSimpleLegendNode( nodeLayer, r->legendClassificationAttribute() ) );
   }
 
-  const auto constLegendSymbolItems = r->legendSymbolItems();
-  for ( const QgsLegendSymbolItem &i : constLegendSymbolItems )
+  const QList<QgsLayerTreeModelLegendNode *> rendererNodes = r->createLegendNodes( nodeLayer );
+  for ( QgsLayerTreeModelLegendNode *node : rendererNodes )
   {
-    if ( auto *lDataDefinedSizeLegendSettings = i.dataDefinedSizeLegendSettings() )
-      nodes << new QgsDataDefinedSizeLegendNode( nodeLayer, *lDataDefinedSizeLegendSettings );
-    else
+    if ( QgsSymbolLegendNode *legendNode = qobject_cast< QgsSymbolLegendNode *>( node ) )
     {
-      QgsSymbolLegendNode *legendNode = new QgsSymbolLegendNode( nodeLayer, i );
-      if ( mTextOnSymbolEnabled && mTextOnSymbolContent.contains( i.ruleKey() ) )
+      const QString ruleKey = legendNode->data( static_cast< int >( QgsLayerTreeModelLegendNode::CustomRole::RuleKey ) ).toString();
+      if ( mTextOnSymbolEnabled && mTextOnSymbolContent.contains( ruleKey ) )
       {
-        legendNode->setTextOnSymbolLabel( mTextOnSymbolContent.value( i.ruleKey() ) );
+        legendNode->setTextOnSymbolLabel( mTextOnSymbolContent.value( ruleKey ) );
         legendNode->setTextOnSymbolTextFormat( mTextOnSymbolTextFormat );
       }
-      nodes << legendNode;
     }
+    nodes << node;
   }
 
-  if ( nodes.count() == 1 && nodes[0]->data( Qt::EditRole ).toString().isEmpty() )
+  if ( nodes.count() == 1 && nodes[0]->data( Qt::EditRole ).toString().isEmpty() && qobject_cast< QgsSymbolLegendNode * >( nodes[0] ) )
     nodes[0]->setEmbeddedInParent( true );
 
-
   if ( mLayer->diagramsEnabled() )
   {
     const auto constLegendItems = mLayer->diagramRenderer()->legendItems( nodeLayer );
@@ -440,7 +437,6 @@ QList<QgsLayerTreeModelLegendNode *> QgsDefaultVectorLayerLegend::createLayerTre
     }
   }
 
-
   return nodes;
 }
 

src/core/symbology/qgsheatmaprenderer.cpp

@@ -23,6 +23,7 @@
 #include "qgscolorrampimpl.h"
 #include "qgsrendercontext.h"
 #include "qgsstyleentityvisitor.h"
+#include "qgscolorramplegendnode.h"
 
 #include <QDomDocument>
 #include <QDomElement>
@@ -31,6 +32,8 @@ QgsHeatmapRenderer::QgsHeatmapRenderer()
   : QgsFeatureRenderer( QStringLiteral( "heatmapRenderer" ) )
 {
   mGradientRamp = new QgsGradientColorRamp( QColor( 255, 255, 255 ), QColor( 0, 0, 0 ) );
+  mLegendSettings.setMinimumLabel( QObject::tr( "Minimum" ) );
+  mLegendSettings.setMaximumLabel( QObject::tr( "Maximum" ) );
 }
 
 QgsHeatmapRenderer::~QgsHeatmapRenderer()
@@ -284,6 +287,7 @@ QgsHeatmapRenderer *QgsHeatmapRenderer::clone() const
   newRenderer->setMaximumValue( mExplicitMax );
   newRenderer->setRenderQuality( mRenderQuality );
   newRenderer->setWeightExpression( mWeightExpressionString );
+  newRenderer->setLegendSettings( mLegendSettings );
   copyRendererData( newRenderer );
 
   return newRenderer;
@@ -316,12 +320,16 @@ QgsFeatureRenderer *QgsHeatmapRenderer::create( QDomElement &element, const QgsR
   {
     r->setColorRamp( QgsSymbolLayerUtils::loadColorRamp( sourceColorRampElem ) );
   }
+
+  QgsColorRampLegendNodeSettings legendSettings;
+  legendSettings.readXml( element, context );
+  r->setLegendSettings( legendSettings );
+
   return r;
 }
 
 QDomElement QgsHeatmapRenderer::save( QDomDocument &doc, const QgsReadWriteContext &context )
 {
-  Q_UNUSED( context )
   QDomElement rendererElem = doc.createElement( RENDERER_TAG_NAME );
   rendererElem.setAttribute( QStringLiteral( "type" ), QStringLiteral( "heatmapRenderer" ) );
   rendererElem.setAttribute( QStringLiteral( "radius" ), QString::number( mRadius ) );
@@ -336,6 +344,7 @@ QDomElement QgsHeatmapRenderer::save( QDomDocument &doc, const QgsReadWriteConte
     const QDomElement colorRampElem = QgsSymbolLayerUtils::saveColorRamp( QStringLiteral( "[source]" ), mGradientRamp, doc );
     rendererElem.appendChild( colorRampElem );
   }
+  mLegendSettings.writeXml( doc, rendererElem, context );
 
   saveRendererData( doc, rendererElem, context );
 
@@ -395,8 +404,25 @@ bool QgsHeatmapRenderer::accept( QgsStyleEntityVisitorInterface *visitor ) const
   return true;
 }
 
+QList<QgsLayerTreeModelLegendNode *> QgsHeatmapRenderer::createLegendNodes( QgsLayerTreeLayer *nodeLayer ) const
+{
+  return
+  {
+    new QgsColorRampLegendNode( nodeLayer,
+                                mGradientRamp->clone(),
+                                mLegendSettings,
+                                0,
+                                1 )
+  };
+}
+
 void QgsHeatmapRenderer::setColorRamp( QgsColorRamp *ramp )
 {
   delete mGradientRamp;
   mGradientRamp = ramp;
 }
+
+void QgsHeatmapRenderer::setLegendSettings( const QgsColorRampLegendNodeSettings &settings )
+{
+  mLegendSettings = settings;
+}