Port current geometry from atlas to layouts

Author: nyalldawson

python/core/layout/qgslayoutcontext.sip

@@ -104,7 +104,21 @@ Returns the current feature for evaluating the layout. This feature may
 be used for altering an item's content and appearance for a report
 or atlas layout.
 
+.. seealso:: :py:func:`currentGeometry()`
+
 .. seealso:: :py:func:`setFeature()`
+%End
+
+    QgsGeometry currentGeometry( const QgsCoordinateReferenceSystem &crs = QgsCoordinateReferenceSystem() ) const;
+%Docstring
+Returns the current feature() geometry in the given ``crs``.
+If no CRS is specified, the original feature geometry is returned.
+
+Reprojection only works if a valid layer is set for layer().
+
+.. seealso:: :py:func:`feature()`
+
+.. seealso:: :py:func:`layer()`
 %End
 
     QgsVectorLayer *layer() const;

src/core/layout/qgslayoutcontext.cpp

@@ -74,9 +74,42 @@ QgsRenderContext::Flags QgsLayoutContext::renderContextFlags() const
 void QgsLayoutContext::setFeature( const QgsFeature &feature )
 {
   mFeature = feature;
+  mGeometryCache.clear();
   emit changed();
 }
 
+QgsGeometry QgsLayoutContext::currentGeometry( const QgsCoordinateReferenceSystem &crs ) const
+{
+  if ( !crs.isValid() )
+  {
+    // no projection, return the native geometry
+    return mFeature.geometry();
+  }
+
+  if ( !mLayer || !mFeature.isValid() || !mFeature.hasGeometry() )
+  {
+    return QgsGeometry();
+  }
+
+  if ( mLayer->crs() == crs )
+  {
+    // no projection, return the native geometry
+    return mFeature.geometry();
+  }
+
+  auto it = mGeometryCache.constFind( crs.srsid() );
+  if ( it != mGeometryCache.constEnd() )
+  {
+    // we have it in cache, return it
+    return it.value();
+  }
+
+  QgsGeometry transformed = mFeature.geometry();
+  transformed.transform( QgsCoordinateTransform( mLayer->crs(), crs, mLayout->project() ) );
+  mGeometryCache[crs.srsid()] = transformed;
+  return transformed;
+}
+
 QgsVectorLayer *QgsLayoutContext::layer() const
 {
   return mLayer;

src/core/layout/qgslayoutcontext.h

@@ -107,10 +107,22 @@ class CORE_EXPORT QgsLayoutContext : public QObject
      * Returns the current feature for evaluating the layout. This feature may
      * be used for altering an item's content and appearance for a report
      * or atlas layout.
+     * \see currentGeometry()
      * \see setFeature()
      */
     QgsFeature feature() const { return mFeature; }
 
+    /**
+     * Returns the current feature() geometry in the given \a crs.
+     * If no CRS is specified, the original feature geometry is returned.
+     *
+     * Reprojection only works if a valid layer is set for layer().
+     *
+     * \see feature()
+     * \see layer()
+     */
+    QgsGeometry currentGeometry( const QgsCoordinateReferenceSystem &crs = QgsCoordinateReferenceSystem() ) const;
+
     /**
      * Returns the vector layer associated with the layout's context.
      * \see setLayer()
@@ -262,6 +274,9 @@ class CORE_EXPORT QgsLayoutContext : public QObject
     bool mBoundingBoxesVisible = true;
     bool mPagesVisible = true;
 
+    // projected geometry cache
+    mutable QMap<long, QgsGeometry> mGeometryCache;
+
     friend class QgsLayoutExporter;
     friend class TestQgsLayout;
     friend class LayoutContextPreviewSettingRestorer;

tests/src/core/testqgslayoutcontext.cpp

@@ -19,6 +19,9 @@
 #include "qgis.h"
 #include "qgsfeature.h"
 #include "qgsvectorlayer.h"
+#include "qgsgeometry.h"
+#include "qgsproject.h"
+#include "qgslayout.h"
 #include <QObject>
 #include "qgstest.h"
 #include <QtTest/QSignalSpy>
@@ -40,6 +43,7 @@ class TestQgsLayoutContext: public QObject
     void renderContextFlags();
     void boundingBoxes();
     void exportLayer();
+    void geometry();
 
   private:
     QString mReport;
@@ -198,5 +202,45 @@ void TestQgsLayoutContext::exportLayer()
   QCOMPARE( context.currentExportLayer(), 1 );
 }
 
+void TestQgsLayoutContext::geometry()
+{
+  QgsProject p;
+  QgsLayout l( &p );
+  QgsLayoutContext context( &l );
+
+  // no feature set
+  QVERIFY( context.currentGeometry().isNull() );
+  QVERIFY( context.currentGeometry( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:3111" ) ) ).isNull() );
+
+  // no layer set
+  QgsFeature f;
+  f.setGeometry( QgsGeometry::fromWkt( QStringLiteral( "LineString( 144 -38, 145 -39 )" ) ) );
+  context.setFeature( f );
+  QCOMPARE( context.currentGeometry().asWkt(), f.geometry().asWkt() );
+  QVERIFY( context.currentGeometry( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:3111" ) ) ).isNull() );
+
+  //with layer
+  QgsVectorLayer *layer = new QgsVectorLayer( QStringLiteral( "Point?crs=EPSG:4326&field=id_a:integer" ), QStringLiteral( "A" ), QStringLiteral( "memory" ) );
+  context.setLayer( layer );
+
+  QCOMPARE( context.currentGeometry().asWkt(), f.geometry().asWkt() );
+  QVERIFY( !context.currentGeometry( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:3111" ) ) ).isNull() );
+  QCOMPARE( context.currentGeometry( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:3111" ) ) ).asWkt( 0 ), QStringLiteral( "LineString (2412169 2388563, 2500000 2277996)" ) );
+
+  // should be cached
+  QCOMPARE( context.currentGeometry( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:3111" ) ) ).asWkt( 0 ), QStringLiteral( "LineString (2412169 2388563, 2500000 2277996)" ) );
+
+  // layer crs
+  QCOMPARE( context.currentGeometry( layer->crs() ).asWkt(), f.geometry().asWkt() );
+
+  // clear cache
+  QgsFeature f2;
+  context.setFeature( f2 );
+  QVERIFY( context.currentGeometry().isNull() );
+  QVERIFY( context.currentGeometry( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:3111" ) ) ).isNull() );
+
+  delete layer;
+}
+
 QGSTEST_MAIN( TestQgsLayoutContext )
 #include "testqgslayoutcontext.moc"