Add rendered callout details to QgsLabelingResults for retrieval afte…

…r a map render completes

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

@@ -209,6 +209,27 @@ being rendered.
 Returns the coordinate transform to convert from the original layer associated with
 the callout to the destination map CRS.
 
+.. versionadded:: 3.20
+%End
+
+        void addCalloutPosition( const QgsCalloutPosition &position );
+%Docstring
+Adds a rendered callout position.
+
+The position details such as the callout line origin and destination should be populated by the
+callout subclass during rendering operations.
+
+.. note::
+
+   the feature ID, layer ID and provider ID of the :py:class:`QgsCalloutPosition` will be automatically populated.
+
+.. versionadded:: 3.20
+%End
+
+        QList< QgsCalloutPosition > positions() const;
+%Docstring
+Returns the list of rendered callout positions.
+
 .. versionadded:: 3.20
 %End
 

python/core/auto_generated/labeling/qgscalloutposition.sip.in

@@ -0,0 +1,98 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/labeling/qgscalloutposition.h                               *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+
+class QgsCalloutPosition
+{
+%Docstring
+Represents the calculated placement of a map label callout line.
+
+.. versionadded:: 3.20
+%End
+
+%TypeHeaderCode
+#include "qgscalloutposition.h"
+%End
+  public:
+
+    QgsCalloutPosition( QgsFeatureId id, const QString &layer, const QString &providerId = QString() );
+%Docstring
+Constructor for QgsCalloutPosition.
+
+:param id: associated feature ID
+:param layer: ID of associated map layer
+:param providerId: ID of associated label provider
+%End
+
+    QgsCalloutPosition();
+%Docstring
+Constructor for QgsCalloutPosition
+%End
+
+    QgsFeatureId featureId;
+
+    QString layerID;
+
+    QString providerID;
+
+    QPointF origin() const;
+%Docstring
+Returns the origin of the callout line, in map coordinates.
+
+The origin of the callout line is the line point associated with the label text.
+
+.. seealso:: :py:func:`setOrigin`
+
+.. seealso:: :py:func:`destination`
+%End
+
+    void setOrigin( const QPointF &origin );
+%Docstring
+Sets the ``origin`` of the callout line, in map coordinates.
+
+The origin of the callout line is the line point associated with the label text.
+
+.. seealso:: :py:func:`origin`
+
+.. seealso:: :py:func:`setDestination`
+%End
+
+    QPointF destination() const;
+%Docstring
+Returns the destination of the callout line, in map coordinates.
+
+The destination of the callout line is the line point associated with the feature's geometry.
+
+.. seealso:: :py:func:`setDestination`
+
+.. seealso:: :py:func:`origin`
+%End
+
+    void setDestination( const QPointF &destination );
+%Docstring
+Sets the ``destination`` of the callout line, in map coordinates.
+
+The destination of the callout line is the line point associated with the feature's geometry.
+
+.. seealso:: :py:func:`destination`
+
+.. seealso:: :py:func:`setOrigin`
+%End
+
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/labeling/qgscalloutposition.h                               *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

python/core/auto_generated/labeling/qgslabelingresults.sip.in

@@ -8,6 +8,7 @@
 
 
 
+
 class QgsLabelingResults
 {
 %Docstring
@@ -32,6 +33,15 @@ Returns the details of any labels placed at the specifed point (in map coordinat
     QList<QgsLabelPosition> labelsWithinRect( const QgsRectangle &r ) const;
 %Docstring
 Returns the details of any labels placed within the specifed rectangle (in map coordinates).
+%End
+
+    QList<QgsCalloutPosition> calloutsWithinRectangle( const QgsRectangle &rectangle ) const;
+%Docstring
+Returns a list of callouts with origins or destinations inside the given ``rectangle``.
+
+The ``rectangle`` is specified in map coordinates.
+
+.. versionadded:: 3.20
 %End
 
     void setMapSettings( const QgsMapSettings &settings );

python/core/auto_generated/labeling/qgslabelsearchtree.sip.in

@@ -43,6 +43,18 @@ Removes and deletes all the entries.
 
 
 
+
+    QList<const QgsCalloutPosition *> calloutsInRectangle( const QgsRectangle &rectangle ) const;
+%Docstring
+Returns the list of callouts with origins or destinations inside the given ``rectangle``.
+
+The ``rectangle`` is specified in map coordinates.
+
+QgsLabelSearchTree keeps ownership, don't delete the returned objects.
+
+.. versionadded:: 3.20
+%End
+
     void setMapSettings( const QgsMapSettings &settings );
 %Docstring
 Sets the map ``settings`` associated with the labeling run.

python/core/core_auto.sip

@@ -325,6 +325,7 @@
 %Include auto_generated/gps/qgsgpsdconnection.sip
 %Include auto_generated/gps/qgsgpsdetector.sip
 %Include auto_generated/gps/qgsnmeaconnection.sip
+%Include auto_generated/labeling/qgscalloutposition.sip
 %Include auto_generated/labeling/qgslabeling.sip
 %Include auto_generated/labeling/qgslabelingenginesettings.sip
 %Include auto_generated/labeling/qgslabelingresults.sip
@@ -630,5 +631,4 @@
 %Include auto_generated/gps/qgsqtlocationconnection.sip
 %Include auto_generated/gps/qgsgpsconnectionregistry.sip
 %Include auto_generated/symbology/qgsmasksymbollayer.sip
-%Include auto_generated/labeling/qgslabelthinningsettings.sip
 %Include auto_generated/qgsuserprofile.sip

src/app/labeling/qgsmaptoollabel.cpp

@@ -34,6 +34,7 @@
 #include "qgsmapmouseevent.h"
 #include "qgsadvanceddigitizingdockwidget.h"
 #include "qgsstatusbar.h"
+#include "qgslabelingresults.h"
 
 #include <QMouseEvent>
 

src/app/labeling/qgsmaptoolshowhidelabels.cpp

@@ -26,7 +26,7 @@
 #include "qgsmaptoolselectutils.h"
 #include "qgsrubberband.h"
 #include "qgslogger.h"
-
+#include "qgslabelingresults.h"
 
 QgsMapToolShowHideLabels::QgsMapToolShowHideLabels( QgsMapCanvas *canvas, QgsAdvancedDigitizingDockWidget *cadDock )
   : QgsMapToolLabel( canvas, cadDock )

src/core/CMakeLists.txt

@@ -1212,6 +1212,7 @@ set(QGIS_CORE_HDRS
   gps/qgsgpsdetector.h
   gps/qgsnmeaconnection.h
 
+  labeling/qgscalloutposition.h
   labeling/qgslabelfeature.h
   labeling/qgslabeling.h
   labeling/qgslabelingengine.h

src/core/callouts/qgscallout.cpp

@@ -650,7 +650,14 @@ void QgsSimpleLineCallout::draw( QgsRenderContext &context, QRectF rect, const d
       }
     }
 
-    mLineSymbol->renderPolyline( line.asQPolygonF(), nullptr, context );
+    const QPolygonF points = line.asQPolygonF();
+
+    QgsCalloutPosition position;
+    position.setOrigin( context.mapToPixel().toMapCoordinates( points.at( 0 ).x(), points.at( 0 ).y() ).toQPointF() );
+    position.setDestination( context.mapToPixel().toMapCoordinates( points.constLast().x(), points.constLast().y() ).toQPointF() );
+    calloutContext.addCalloutPosition( position );
+
+    mLineSymbol->renderPolyline( points, nullptr, context );
   };
 
   bool toAllParts = mDrawCalloutToAllParts;
@@ -762,7 +769,14 @@ void QgsManhattanLineCallout::draw( QgsRenderContext &context, QRectF rect, cons
       }
     }
 
-    lineSymbol()->renderPolyline( line.asQPolygonF(), nullptr, context );
+    const QPolygonF points = line.asQPolygonF();
+
+    QgsCalloutPosition position;
+    position.setOrigin( context.mapToPixel().toMapCoordinates( points.at( 0 ).x(), points.at( 0 ).y() ).toQPointF() );
+    position.setDestination( context.mapToPixel().toMapCoordinates( points.constLast().x(), points.constLast().y() ).toQPointF() );
+    calloutContext.addCalloutPosition( position );
+
+    lineSymbol()->renderPolyline( points, nullptr, context );
   };
 
   bool toAllParts = drawCalloutToAllParts();

src/core/callouts/qgscallout.h

@@ -23,6 +23,7 @@
 #include "qgsreadwritecontext.h"
 #include "qgspropertycollection.h"
 #include "qgsmapunitscale.h"
+#include "qgscalloutposition.h"
 #include <QString>
 #include <QRectF>
 #include <memory>
@@ -236,9 +237,30 @@ class CORE_EXPORT QgsCallout
          */
         QgsCoordinateTransform originalFeatureToMapTransform( const QgsRenderContext &renderContext ) const;
 
+        /**
+         * Adds a rendered callout position.
+         *
+         * The position details such as the callout line origin and destination should be populated by the
+         * callout subclass during rendering operations.
+         *
+         * \note the feature ID, layer ID and provider ID of the QgsCalloutPosition will be automatically populated.
+         *
+         * \since QGIS 3.20
+         */
+        void addCalloutPosition( const QgsCalloutPosition &position ) { return mPositions.push_back( position ); }
+
+        /**
+         * Returns the list of rendered callout positions.
+         *
+         * \since QGIS 3.20
+         */
+        QList< QgsCalloutPosition > positions() const { return mPositions; }
+
       private:
         //! Lazy initialized coordinate transform from original feature CRS to map CRS
         mutable QgsCoordinateTransform mOriginalFeatureToMapTransform;
+
+        QList< QgsCalloutPosition > mPositions;
     };
 
     /**

src/core/labeling/qgscalloutposition.h

@@ -0,0 +1,113 @@
+/***************************************************************************
+  qgscalloutposition.h
+  -------------------
+   begin                : February 2021
+   copyright            : (C) Nyall Dawson
+   email                : nyall dot dawson at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSCALLOUTPOSITION_H
+#define QGSCALLOUTPOSITION_H
+
+#include "qgis_core.h"
+#include "qgis_sip.h"
+
+#include "qgsfeatureid.h"
+
+#include <QPointF>
+
+/**
+ * \ingroup core
+ * \class QgsCalloutPosition
+ * \brief Represents the calculated placement of a map label callout line.
+ * \since QGIS 3.20
+ */
+class CORE_EXPORT QgsCalloutPosition
+{
+  public:
+
+    /**
+     * Constructor for QgsCalloutPosition.
+     * \param id associated feature ID
+     * \param layer ID of associated map layer
+     * \param providerId ID of associated label provider
+     */
+    QgsCalloutPosition( QgsFeatureId id, const QString &layer, const QString &providerId = QString() )
+      : featureId( id )
+      , layerID( layer )
+      , providerID( providerId )
+    {}
+
+    //! Constructor for QgsCalloutPosition
+    QgsCalloutPosition() = default;
+
+    /**
+     * ID of feature associated with this callout.
+     */
+    QgsFeatureId featureId = FID_NULL;
+
+    /**
+     * ID of associated map layer.
+     */
+    QString layerID;
+
+    /**
+     * ID of the associated label provider.
+     */
+    QString providerID;
+
+    /**
+     * Returns the origin of the callout line, in map coordinates.
+     *
+     * The origin of the callout line is the line point associated with the label text.
+     *
+     * \see setOrigin()
+     * \see destination()
+     */
+    QPointF origin() const { return mOrigin; }
+
+    /**
+     * Sets the \a origin of the callout line, in map coordinates.
+     *
+     * The origin of the callout line is the line point associated with the label text.
+     *
+     * \see origin()
+     * \see setDestination()
+     */
+    void setOrigin( const QPointF &origin ) { mOrigin = origin; }
+
+    /**
+     * Returns the destination of the callout line, in map coordinates.
+     *
+     * The destination of the callout line is the line point associated with the feature's geometry.
+     *
+     * \see setDestination()
+     * \see origin()
+     */
+    QPointF destination() const { return mDestination; }
+
+    /**
+     * Sets the \a destination of the callout line, in map coordinates.
+     *
+     * The destination of the callout line is the line point associated with the feature's geometry.
+     *
+     * \see destination()
+     * \see setOrigin()
+     */
+    void setDestination( const QPointF &destination ) { mDestination = destination; }
+
+  private:
+
+    QPointF mOrigin;
+
+    QPointF mDestination;
+};
+
+#endif // QGSCALLOUTPOSITION_H