[feature] Allow end point marker symbols for balloon callout style

Allows rendering a marker symbol below the endpoint of the balloon
callout. Designed to allow balloon callouts to reproduce the same
visual appearance as the older annotation framework items.

python/PyQt6/core/auto_generated/callouts/qgscallout.sip.in

@@ -908,6 +908,35 @@ Sets the fill ``symbol`` used to render the callout. Ownership of ``symbol`` is
 transferred to the callout.
 
 .. seealso:: :py:func:`fillSymbol`
+%End
+
+    QgsMarkerSymbol *markerSymbol();
+%Docstring
+Returns the marker symbol used to render the callout endpoint.
+
+May be ``None``, if no endpoint marker will be used.
+
+The marker will always be rendered below the fill symbol for the callout.
+
+Ownership is not transferred.
+
+.. seealso:: :py:func:`setMarkerSymbol`
+
+.. versionadded:: 3.40
+%End
+
+    void setMarkerSymbol( QgsMarkerSymbol *symbol /Transfer/ );
+%Docstring
+Sets the marker ``symbol`` used to render the callout endpoint. Ownership of ``symbol`` is
+transferred to the callout.
+
+Set to ``None`` to disable the endpoint marker.
+
+The marker will always be rendered below the fill symbol for the callout.
+
+.. seealso:: :py:func:`markerSymbol`
+
+.. versionadded:: 3.40
 %End
 
     double offsetFromAnchor() const;

python/core/auto_generated/callouts/qgscallout.sip.in

@@ -908,6 +908,35 @@ Sets the fill ``symbol`` used to render the callout. Ownership of ``symbol`` is
 transferred to the callout.
 
 .. seealso:: :py:func:`fillSymbol`
+%End
+
+    QgsMarkerSymbol *markerSymbol();
+%Docstring
+Returns the marker symbol used to render the callout endpoint.
+
+May be ``None``, if no endpoint marker will be used.
+
+The marker will always be rendered below the fill symbol for the callout.
+
+Ownership is not transferred.
+
+.. seealso:: :py:func:`setMarkerSymbol`
+
+.. versionadded:: 3.40
+%End
+
+    void setMarkerSymbol( QgsMarkerSymbol *symbol /Transfer/ );
+%Docstring
+Sets the marker ``symbol`` used to render the callout endpoint. Ownership of ``symbol`` is
+transferred to the callout.
+
+Set to ``None`` to disable the endpoint marker.
+
+The marker will always be rendered below the fill symbol for the callout.
+
+.. seealso:: :py:func:`markerSymbol`
+
+.. versionadded:: 3.40
 %End
 
     double offsetFromAnchor() const;

src/core/callouts/qgscallout.cpp

@@ -31,6 +31,7 @@
 #include "qgspainting.h"
 #include "qgsfillsymbol.h"
 #include "qgslinesymbol.h"
+#include "qgsmarkersymbol.h"
 #include "qgsunittypes.h"
 
 #include <mutex>
@@ -1042,6 +1043,7 @@ QgsBalloonCallout::~QgsBalloonCallout() = default;
 QgsBalloonCallout::QgsBalloonCallout( const QgsBalloonCallout &other )
   : QgsCallout( other )
   , mFillSymbol( other.mFillSymbol ? other.mFillSymbol->clone() : nullptr )
+  , mMarkerSymbol( other.mMarkerSymbol ? other.mMarkerSymbol->clone() : nullptr )
   , mOffsetFromAnchorDistance( other.mOffsetFromAnchorDistance )
   , mOffsetFromAnchorUnit( other.mOffsetFromAnchorUnit )
   , mOffsetFromAnchorScale( other.mOffsetFromAnchorScale )
@@ -1083,6 +1085,11 @@ QVariantMap QgsBalloonCallout::properties( const QgsReadWriteContext &context )
     props[ QStringLiteral( "fillSymbol" ) ] = QgsSymbolLayerUtils::symbolProperties( mFillSymbol.get() );
   }
 
+  if ( mMarkerSymbol )
+  {
+    props[ QStringLiteral( "markerSymbol" ) ] = QgsSymbolLayerUtils::symbolProperties( mMarkerSymbol.get() );
+  }
+
   props[ QStringLiteral( "offsetFromAnchor" ) ] = mOffsetFromAnchorDistance;
   props[ QStringLiteral( "offsetFromAnchorUnit" ) ] = QgsUnitTypes::encodeUnit( mOffsetFromAnchorUnit );
   props[ QStringLiteral( "offsetFromAnchorMapUnitScale" ) ] = QgsSymbolLayerUtils::encodeMapUnitScale( mOffsetFromAnchorScale );
@@ -1105,13 +1112,25 @@ void QgsBalloonCallout::readProperties( const QVariantMap &props, const QgsReadW
 {
   QgsCallout::readProperties( props, context );
 
-  const QString fillSymbolDef = props.value( QStringLiteral( "fillSymbol" ) ).toString();
-  QDomDocument doc( QStringLiteral( "symbol" ) );
-  doc.setContent( fillSymbolDef );
-  const QDomElement symbolElem = doc.firstChildElement( QStringLiteral( "symbol" ) );
-  std::unique_ptr< QgsFillSymbol > fillSymbol( QgsSymbolLayerUtils::loadSymbol< QgsFillSymbol >( symbolElem, context ) );
-  if ( fillSymbol )
-    mFillSymbol = std::move( fillSymbol );
+  {
+    const QString fillSymbolDef = props.value( QStringLiteral( "fillSymbol" ) ).toString();
+    QDomDocument doc( QStringLiteral( "symbol" ) );
+    doc.setContent( fillSymbolDef );
+    const QDomElement symbolElem = doc.firstChildElement( QStringLiteral( "symbol" ) );
+    std::unique_ptr< QgsFillSymbol > fillSymbol( QgsSymbolLayerUtils::loadSymbol< QgsFillSymbol >( symbolElem, context ) );
+    if ( fillSymbol )
+      mFillSymbol = std::move( fillSymbol );
+  }
+
+  {
+    const QString markerSymbolDef = props.value( QStringLiteral( "markerSymbol" ) ).toString();
+    QDomDocument doc( QStringLiteral( "symbol" ) );
+    doc.setContent( markerSymbolDef );
+    const QDomElement symbolElem = doc.firstChildElement( QStringLiteral( "symbol" ) );
+    std::unique_ptr< QgsMarkerSymbol > markerSymbol( QgsSymbolLayerUtils::loadSymbol< QgsMarkerSymbol >( symbolElem, context ) );
+    if ( markerSymbol )
+      mMarkerSymbol = std::move( markerSymbol );
+  }
 
   mOffsetFromAnchorDistance = props.value( QStringLiteral( "offsetFromAnchor" ), 0 ).toDouble();
   mOffsetFromAnchorUnit = QgsUnitTypes::decodeRenderUnit( props.value( QStringLiteral( "offsetFromAnchorUnit" ) ).toString() );
@@ -1134,20 +1153,26 @@ void QgsBalloonCallout::startRender( QgsRenderContext &context )
   QgsCallout::startRender( context );
   if ( mFillSymbol )
     mFillSymbol->startRender( context );
+  if ( mMarkerSymbol )
+    mMarkerSymbol->startRender( context );
 }
 
 void QgsBalloonCallout::stopRender( QgsRenderContext &context )
 {
   QgsCallout::stopRender( context );
   if ( mFillSymbol )
     mFillSymbol->stopRender( context );
+  if ( mMarkerSymbol )
+    mMarkerSymbol->stopRender( context );
 }
 
 QSet<QString> QgsBalloonCallout::referencedFields( const QgsRenderContext &context ) const
 {
   QSet<QString> fields = QgsCallout::referencedFields( context );
   if ( mFillSymbol )
     fields.unite( mFillSymbol->usedAttributes( context ) );
+  if ( mMarkerSymbol )
+    fields.unite( mMarkerSymbol->usedAttributes( context ) );
   return fields;
 }
 
@@ -1161,11 +1186,30 @@ void QgsBalloonCallout::setFillSymbol( QgsFillSymbol *symbol )
   mFillSymbol.reset( symbol );
 }
 
+QgsMarkerSymbol *QgsBalloonCallout::markerSymbol()
+{
+  return mMarkerSymbol.get();
+}
+
+void QgsBalloonCallout::setMarkerSymbol( QgsMarkerSymbol *symbol )
+{
+  mMarkerSymbol.reset( symbol );
+}
+
 void QgsBalloonCallout::draw( QgsRenderContext &context, const QRectF &rect, const double, const QgsGeometry &anchor, QgsCalloutContext &calloutContext )
 {
   bool destinationIsPinned = false;
   QgsGeometry line = calloutLineToPart( QgsGeometry::fromRect( rect ), anchor.constGet(), context, calloutContext, destinationIsPinned );
 
+  if ( mMarkerSymbol )
+  {
+    if ( const QgsLineString *ls = qgsgeometry_cast< const QgsLineString * >( line.constGet() ) )
+    {
+      QgsPoint anchorPoint = ls->endPoint();
+      mMarkerSymbol->renderPoint( anchorPoint.toQPointF(), nullptr, context );
+    }
+  }
+
   double offsetFromAnchor = mOffsetFromAnchorDistance;
   if ( dataDefinedProperties().isActive( QgsCallout::Property::OffsetFromAnchor ) )
   {

src/core/callouts/qgscallout.h

@@ -33,6 +33,7 @@
 #include <memory>
 
 class QgsLineSymbol;
+class QgsMarkerSymbol;
 class QgsFillSymbol;
 class QgsGeometry;
 class QgsRenderContext;
@@ -919,6 +920,33 @@ class CORE_EXPORT QgsBalloonCallout : public QgsCallout
      */
     void setFillSymbol( QgsFillSymbol *symbol SIP_TRANSFER );
 
+    /**
+     * Returns the marker symbol used to render the callout endpoint.
+     *
+     * May be NULLPTR, if no endpoint marker will be used.
+     *
+     * The marker will always be rendered below the fill symbol for the callout.
+     *
+     * Ownership is not transferred.
+     *
+     * \see setMarkerSymbol()
+     * \since QGIS 3.40
+     */
+    QgsMarkerSymbol *markerSymbol();
+
+    /**
+     * Sets the marker \a symbol used to render the callout endpoint. Ownership of \a symbol is
+     * transferred to the callout.
+     *
+     * Set to NULLPTR to disable the endpoint marker.
+     *
+     * The marker will always be rendered below the fill symbol for the callout.
+     *
+     * \see markerSymbol()
+     * \since QGIS 3.40
+     */
+    void setMarkerSymbol( QgsMarkerSymbol *symbol SIP_TRANSFER );
+
     /**
      * Returns the offset distance from the anchor point at which to start the line. Units are specified through offsetFromAnchorUnit().
      * \see setOffsetFromAnchor()
@@ -1125,6 +1153,7 @@ class CORE_EXPORT QgsBalloonCallout : public QgsCallout
 #endif
 
     std::unique_ptr< QgsFillSymbol > mFillSymbol;
+    std::unique_ptr< QgsMarkerSymbol > mMarkerSymbol;
 
     double mOffsetFromAnchorDistance = 0;
     Qgis::RenderUnit mOffsetFromAnchorUnit = Qgis::RenderUnit::Millimeters;

src/gui/callouts/qgscalloutwidget.cpp

@@ -23,6 +23,7 @@
 #include "qgsauxiliarystorage.h"
 #include "qgslinesymbol.h"
 #include "qgsfillsymbol.h"
+#include "qgsmarkersymbol.h"
 
 QgsExpressionContext QgsCalloutWidget::createExpressionContext() const
 {
@@ -565,7 +566,14 @@ QgsBalloonCalloutWidget::QgsBalloonCalloutWidget( QgsMapLayer *vl, QWidget *pare
   mCalloutFillStyleButton->setDialogTitle( tr( "Balloon Symbol" ) );
   mCalloutFillStyleButton->registerExpressionContextGenerator( this );
 
+  mMarkerSymbolButton->setSymbolType( Qgis::SymbolType::Marker );
+  mMarkerSymbolButton->setDialogTitle( tr( "Marker Symbol" ) );
+  mMarkerSymbolButton->registerExpressionContextGenerator( this );
+  mMarkerSymbolButton->setShowNull( true );
+  mMarkerSymbolButton->setToNull();
+
   mCalloutFillStyleButton->setLayer( qobject_cast< QgsVectorLayer * >( vl ) );
+  mMarkerSymbolButton->setLayer( qobject_cast< QgsVectorLayer * >( vl ) );
   mOffsetFromAnchorUnitWidget->setUnits( QgsUnitTypes::RenderUnitList() << Qgis::RenderUnit::Millimeters << Qgis::RenderUnit::MetersInMapUnits << Qgis::RenderUnit::MapUnits << Qgis::RenderUnit::Pixels
                                          << Qgis::RenderUnit::Points << Qgis::RenderUnit::Inches );
   mMarginUnitWidget->setUnits( QgsUnitTypes::RenderUnitList() << Qgis::RenderUnit::Millimeters << Qgis::RenderUnit::MetersInMapUnits << Qgis::RenderUnit::MapUnits << Qgis::RenderUnit::Pixels
@@ -593,6 +601,7 @@ QgsBalloonCalloutWidget::QgsBalloonCalloutWidget( QgsMapLayer *vl, QWidget *pare
   connect( mAnchorPointComboBox, static_cast<void ( QComboBox::* )( int )>( &QComboBox::currentIndexChanged ), this, &QgsBalloonCalloutWidget::mAnchorPointComboBox_currentIndexChanged );
 
   connect( mCalloutFillStyleButton, &QgsSymbolButton::changed, this, &QgsBalloonCalloutWidget::fillSymbolChanged );
+  connect( mMarkerSymbolButton, &QgsSymbolButton::changed, this, &QgsBalloonCalloutWidget::markerSymbolChanged );
 
   connect( mSpinBottomMargin, qOverload< double >( &QDoubleSpinBox::valueChanged ), this, [ = ]( double value )
   {
@@ -691,6 +700,10 @@ void QgsBalloonCalloutWidget::setCallout( const QgsCallout *callout )
   whileBlocking( mCornerRadiusSpin )->setValue( mCallout->cornerRadius() );
 
   whileBlocking( mCalloutFillStyleButton )->setSymbol( mCallout->fillSymbol()->clone() );
+  if ( QgsMarkerSymbol *marker = mCallout->markerSymbol() )
+    whileBlocking( mMarkerSymbolButton )->setSymbol( marker->clone() );
+  else
+    whileBlocking( mMarkerSymbolButton )->setToNull();
 
   whileBlocking( mAnchorPointComboBox )->setCurrentIndex( mAnchorPointComboBox->findData( static_cast< int >( callout->anchorPoint() ) ) );
 
@@ -742,6 +755,12 @@ void QgsBalloonCalloutWidget::fillSymbolChanged()
   emit changed();
 }
 
+void QgsBalloonCalloutWidget::markerSymbolChanged()
+{
+  mCallout->setMarkerSymbol( mMarkerSymbolButton->isNull() ? nullptr : mMarkerSymbolButton->clonedSymbol< QgsMarkerSymbol >() );
+  emit changed();
+}
+
 void QgsBalloonCalloutWidget::mAnchorPointComboBox_currentIndexChanged( int index )
 {
   mCallout->setAnchorPoint( static_cast<QgsCallout::AnchorPoint>( mAnchorPointComboBox->itemData( index ).toInt() ) );

src/gui/callouts/qgscalloutwidget.h

@@ -252,6 +252,7 @@ class GUI_EXPORT QgsBalloonCalloutWidget : public QgsCalloutWidget, private Ui::
     void offsetFromAnchorUnitWidgetChanged();
     void offsetFromAnchorChanged();
     void fillSymbolChanged();
+    void markerSymbolChanged();
     void mAnchorPointComboBox_currentIndexChanged( int index );
     void mCalloutBlendComboBox_currentIndexChanged( int index );