Add clipping regions to QgsMapSettings/QgsRenderContext API

python/core/auto_generated/qgsmapsettings.sip.in

@@ -667,6 +667,24 @@ Returns the list of regions to avoid placing labels within.
 .. seealso:: :py:func:`labelBoundaryGeometry`
 
 .. versionadded:: 3.6
+%End
+
+    void addClippingRegion( const QgsMapClippingRegion &region );
+%Docstring
+Adds a new clipping ``region`` to the map settings.
+
+.. seealso:: :py:func:`clippingRegions`
+
+.. versionadded:: 3.16
+%End
+
+    QList< QgsMapClippingRegion > clippingRegions() const;
+%Docstring
+Returns the list of clipping regions to apply to the map.
+
+.. seealso:: :py:func:`addClippingRegion`
+
+.. versionadded:: 3.16
 %End
 
     void setSimplifyMethod( const QgsVectorSimplifyMethod &method );

python/core/auto_generated/qgsrendercontext.sip.in

@@ -12,7 +12,6 @@
 
 
 
-
 class QgsRenderContext : QgsTemporalRangeObject
 {
 %Docstring
@@ -27,6 +26,7 @@ to be rendered etc.
 %End
   public:
     QgsRenderContext();
+    ~QgsRenderContext();
 
     QgsRenderContext( const QgsRenderContext &rh );
 
@@ -787,6 +787,15 @@ Clears the specified custom rendering flag.
 .. seealso:: :py:func:`setCustomRenderingFlag`
 
 .. versionadded:: 3.12
+%End
+
+    QList< QgsMapClippingRegion > clippingRegions() const;
+%Docstring
+Returns the list of clipping regions to apply during the render.
+
+These regions are always in the final destination CRS for the map.
+
+.. versionadded:: 3.16
 %End
 
 };

src/core/qgsmapsettings.cpp

@@ -682,6 +682,16 @@ void QgsMapSettings::setLabelBoundaryGeometry( const QgsGeometry &boundary )
   mLabelBoundaryGeometry = boundary;
 }
 
+void QgsMapSettings::addClippingRegion( const QgsMapClippingRegion &region )
+{
+  mClippingRegions.append( region );
+}
+
+QList<QgsMapClippingRegion> QgsMapSettings::clippingRegions() const
+{
+  return mClippingRegions;
+}
+
 void QgsMapSettings::addRenderedFeatureHandler( QgsRenderedFeatureHandlerInterface *handler )
 {
   mRenderedFeatureHandlers.append( handler );

src/core/qgsmapsettings.h

@@ -33,6 +33,7 @@
 #include "qgsmaplayer.h"
 #include "qgsgeometry.h"
 #include "qgstemporalrangeobject.h"
+#include "qgsmapclippingregion.h"
 
 class QPainter;
 
@@ -578,6 +579,24 @@ class CORE_EXPORT QgsMapSettings : public QgsTemporalRangeObject
      */
     QList< QgsLabelBlockingRegion > labelBlockingRegions() const { return mLabelBlockingRegions; }
 
+    /**
+     * Adds a new clipping \a region to the map settings.
+     *
+     * \see clippingRegions()
+     *
+     * \since QGIS 3.16
+     */
+    void addClippingRegion( const QgsMapClippingRegion &region );
+
+    /**
+     * Returns the list of clipping regions to apply to the map.
+     *
+     * \see addClippingRegion()
+     *
+     * \since QGIS 3.16
+     */
+    QList< QgsMapClippingRegion > clippingRegions() const;
+
     /**
      * Sets the simplification setting to use when rendering vector layers.
      *
@@ -692,6 +711,7 @@ class CORE_EXPORT QgsMapSettings : public QgsTemporalRangeObject
   private:
 
     QList< QgsLabelBlockingRegion > mLabelBlockingRegions;
+    QList< QgsMapClippingRegion > mClippingRegions;
     QList< QgsRenderedFeatureHandlerInterface * > mRenderedFeatureHandlers;
 };
 

src/core/qgsrendercontext.cpp

@@ -37,6 +37,8 @@ QgsRenderContext::QgsRenderContext()
   mDistanceArea.setEllipsoid( mDistanceArea.sourceCrs().ellipsoidAcronym() );
 }
 
+QgsRenderContext::~QgsRenderContext() = default;
+
 QgsRenderContext::QgsRenderContext( const QgsRenderContext &rh )
   : QgsTemporalRangeObject( rh )
   , mFlags( rh.mFlags )
@@ -65,6 +67,7 @@ QgsRenderContext::QgsRenderContext( const QgsRenderContext &rh )
   , mHasRenderedFeatureHandlers( rh.mHasRenderedFeatureHandlers )
   , mCustomRenderingFlags( rh.mCustomRenderingFlags )
   , mDisabledSymbolLayers()
+  , mClippingRegions( rh.mClippingRegions )
 #ifdef QGISDEBUG
   , mHasTransformContext( rh.mHasTransformContext )
 #endif
@@ -98,6 +101,7 @@ QgsRenderContext &QgsRenderContext::operator=( const QgsRenderContext &rh )
   mRenderedFeatureHandlers = rh.mRenderedFeatureHandlers;
   mHasRenderedFeatureHandlers = rh.mHasRenderedFeatureHandlers;
   mCustomRenderingFlags = rh.mCustomRenderingFlags;
+  mClippingRegions = rh.mClippingRegions;
   setIsTemporal( rh.isTemporal() );
   if ( isTemporal() )
     setTemporalRange( rh.temporalRange() );
@@ -209,6 +213,8 @@ QgsRenderContext QgsRenderContext::fromMapSettings( const QgsMapSettings &mapSet
   if ( ctx.isTemporal() )
     ctx.setTemporalRange( mapSettings.temporalRange() );
 
+  ctx.mClippingRegions = mapSettings.clippingRegions();
+
   return ctx;
 }
 
@@ -491,4 +497,9 @@ QList<QgsRenderedFeatureHandlerInterface *> QgsRenderContext::renderedFeatureHan
   return mRenderedFeatureHandlers;
 }
 
+QList<QgsMapClippingRegion> QgsRenderContext::clippingRegions() const
+{
+  return mClippingRegions;
+}
+
 

src/core/qgsrendercontext.h

@@ -43,8 +43,8 @@ class QgsLabelingEngine;
 class QgsMapSettings;
 class QgsRenderedFeatureHandlerInterface;
 class QgsSymbolLayer;
-
 class QgsMaskIdProvider;
+class QgsMapClippingRegion;
 
 
 /**
@@ -58,6 +58,7 @@ class CORE_EXPORT QgsRenderContext : public QgsTemporalRangeObject
 {
   public:
     QgsRenderContext();
+    ~QgsRenderContext() override;
 
     QgsRenderContext( const QgsRenderContext &rh );
     QgsRenderContext &operator=( const QgsRenderContext &rh );
@@ -786,6 +787,15 @@ class CORE_EXPORT QgsRenderContext : public QgsTemporalRangeObject
      */
     void clearCustomRenderingFlag( const QString &flag ) { mCustomRenderingFlags.remove( flag ); }
 
+    /**
+     * Returns the list of clipping regions to apply during the render.
+     *
+     * These regions are always in the final destination CRS for the map.
+     *
+     * \since QGIS 3.16
+     */
+    QList< QgsMapClippingRegion > clippingRegions() const;
+
   private:
 
     Flags mFlags;
@@ -877,6 +887,8 @@ class CORE_EXPORT QgsRenderContext : public QgsTemporalRangeObject
 
     QSet<const QgsSymbolLayer *> mDisabledSymbolLayers;
 
+    QList< QgsMapClippingRegion > mClippingRegions;
+
 #ifdef QGISDEBUG
     bool mHasTransformContext = false;
 #endif

tests/src/core/testqgsmapsettings.cpp

@@ -61,6 +61,7 @@ class TestQgsMapSettings: public QObject
     void testExpressionContext();
     void testRenderedFeatureHandlers();
     void testCustomRenderingFlags();
+    void testClippingRegions();
 
   private:
     QString toString( const QPolygonF &p, int decimalPlaces = 2 ) const;
@@ -588,5 +589,32 @@ void TestQgsMapSettings::testCustomRenderingFlags()
   Q_NOWARN_DEPRECATED_POP
 }
 
+void TestQgsMapSettings::testClippingRegions()
+{
+  QgsMapSettings settings;
+  QVERIFY( settings.clippingRegions().isEmpty() );
+
+  QgsMapClippingRegion region( QgsGeometry::fromWkt( QStringLiteral( "Polygon(( 0 0, 1 0 , 1 1 , 0 1, 0 0 ))" ) ) );
+  settings.addClippingRegion( region );
+  QCOMPARE( settings.clippingRegions().size(), 1 );
+  QCOMPARE( settings.clippingRegions().at( 0 ).geometry().asWkt(), QStringLiteral( "Polygon ((0 0, 1 0, 1 1, 0 1, 0 0))" ) );
+  QgsMapClippingRegion region2( QgsGeometry::fromWkt( QStringLiteral( "Polygon(( 10 0, 11 0 , 11 1 , 10 1, 10 0 ))" ) ) );
+  settings.addClippingRegion( region2 );
+  QCOMPARE( settings.clippingRegions().size(), 2 );
+  QCOMPARE( settings.clippingRegions().at( 0 ).geometry().asWkt(), QStringLiteral( "Polygon ((0 0, 1 0, 1 1, 0 1, 0 0))" ) );
+  QCOMPARE( settings.clippingRegions().at( 1 ).geometry().asWkt(), QStringLiteral( "Polygon ((10 0, 11 0, 11 1, 10 1, 10 0))" ) );
+
+  QgsMapSettings settings2( settings );
+  QCOMPARE( settings2.clippingRegions().size(), 2 );
+  QCOMPARE( settings2.clippingRegions().at( 0 ).geometry().asWkt(), QStringLiteral( "Polygon ((0 0, 1 0, 1 1, 0 1, 0 0))" ) );
+  QCOMPARE( settings2.clippingRegions().at( 1 ).geometry().asWkt(), QStringLiteral( "Polygon ((10 0, 11 0, 11 1, 10 1, 10 0))" ) );
+
+  QgsMapSettings settings3;
+  settings3 = settings;
+  QCOMPARE( settings3.clippingRegions().size(), 2 );
+  QCOMPARE( settings3.clippingRegions().at( 0 ).geometry().asWkt(), QStringLiteral( "Polygon ((0 0, 1 0, 1 1, 0 1, 0 0))" ) );
+  QCOMPARE( settings3.clippingRegions().at( 1 ).geometry().asWkt(), QStringLiteral( "Polygon ((10 0, 11 0, 11 1, 10 1, 10 0))" ) ) ;
+}
+
 QGSTEST_MAIN( TestQgsMapSettings )
 #include "testqgsmapsettings.moc"

tests/src/python/test_qgsrendercontext.py

@@ -23,7 +23,9 @@ from qgis.core import (QgsRenderContext,
                        QgsRectangle,
                        QgsVectorSimplifyMethod,
                        QgsRenderedFeatureHandlerInterface,
-                       QgsDateTimeRange)
+                       QgsDateTimeRange,
+                       QgsMapClippingRegion,
+                       QgsGeometry)
 from qgis.PyQt.QtCore import QSize, QDateTime
 from qgis.PyQt.QtGui import QPainter, QImage
 from qgis.testing import start_app, unittest
@@ -507,6 +509,17 @@ class TestQgsRenderContext(unittest.TestCase):
         self.assertEqual(rc.isTemporal(), False)
         self.assertIsNotNone(rc.temporalRange())
 
+    def testClippingRegion(self):
+        ms = QgsMapSettings()
+        rc = QgsRenderContext.fromMapSettings(ms)
+        self.assertFalse(rc.clippingRegions())
+        ms.addClippingRegion(QgsMapClippingRegion(QgsGeometry.fromWkt('Polygon(( 0 0, 1 0 , 1 1 , 0 1, 0 0 ))')))
+        ms.addClippingRegion(QgsMapClippingRegion(QgsGeometry.fromWkt('Polygon(( 10 0, 11 0 , 11 1 , 10 1, 10 0 ))')))
+        rc = QgsRenderContext.fromMapSettings(ms)
+        self.assertEqual(len(rc.clippingRegions()), 2)
+        self.assertEqual(rc.clippingRegions()[0].geometry().asWkt(), 'Polygon ((0 0, 1 0, 1 1, 0 1, 0 0))')
+        self.assertEqual(rc.clippingRegions()[1].geometry().asWkt(), 'Polygon ((10 0, 11 0, 11 1, 10 1, 10 0))')
+
 
 if __name__ == '__main__':
     unittest.main()