Optimise QgsAbstractGeometry

Make nCoordinates virtual, and provide shortcuts for some
geometry types. The base method which calls coordinateSequence()
is quite slow in certain circumstances.

Speeds up rendering point layers by ~25%, also likely to
speed up lots of geometry heavy operations throughout QGIS

Refs #15752

Author: nyalldawson

python/core/geometry/qgsabstractgeometry.sip

@@ -248,7 +248,7 @@ class QgsAbstractGeometry
 
     /** Returns the number of nodes contained in the geometry
      */
-    int nCoordinates() const;
+    virtual int nCoordinates() const;
 
     /** Returns the point corresponding to a specified vertex id
      */

python/core/geometry/qgscurvepolygon.sip

@@ -68,6 +68,7 @@ class QgsCurvePolygon: public QgsSurface
     virtual bool deleteVertex( QgsVertexId position );
 
     virtual QList< QList< QList< QgsPointV2 > > > coordinateSequence() const;
+    virtual int nCoordinates() const;
     double closestSegment( const QgsPointV2& pt, QgsPointV2& segmentPt,  QgsVertexId& vertexAfter, bool* leftOf, double epsilon ) const;
     bool nextVertex( QgsVertexId& id, QgsPointV2& vertex ) const;
 

python/core/geometry/qgsgeometrycollection.sip

@@ -67,6 +67,7 @@ class QgsGeometryCollection: public QgsAbstractGeometry
     virtual QgsRectangle boundingBox() const;
 
     virtual QList< QList< QList< QgsPointV2 > > > coordinateSequence() const;
+    virtual int nCoordinates() const;
     virtual double closestSegment( const QgsPointV2& pt, QgsPointV2& segmentPt,  QgsVertexId& vertexAfter, bool* leftOf, double epsilon ) const;
     bool nextVertex( QgsVertexId& id, QgsPointV2& vertex ) const;
 

python/core/geometry/qgslinestring.sip

@@ -120,6 +120,7 @@ class QgsLineString: public QgsCurve
     virtual QgsLineString* curveToLine( double tolerance = M_PI_2 / 90, SegmentationToleranceType toleranceType = MaximumAngle ) const /Factory/;
 
     int numPoints() const;
+    virtual int nCoordinates() const;
     void points( QList<QgsPointV2>& pt ) const;
 
     void draw( QPainter& p ) const;

python/core/geometry/qgsmultipoint.sip

@@ -16,6 +16,7 @@ class QgsMultiPointV2: public QgsGeometryCollection
     QDomElement asGML3( QDomDocument& doc, int precision = 17, const QString& ns = "gml" ) const;
     QString asJSON( int precision = 17 ) const;
 
+    virtual int nCoordinates() const;
 
     /** Adds a geometry and takes ownership. Returns true in case of success*/
     virtual bool addGeometry( QgsAbstractGeometry* g /Transfer/ );

python/core/geometry/qgspointv2.sip

@@ -157,6 +157,7 @@ class QgsPointV2: public QgsAbstractGeometry
                     bool transformZ = false );
     void transform( const QTransform& t );
     virtual QList< QList< QList< QgsPointV2 > > > coordinateSequence() const;
+    virtual int nCoordinates() const;
     virtual QgsAbstractGeometry* boundary() const /Factory/;
 
     //low-level editing

src/core/geometry/qgsabstractgeometry.h

@@ -233,7 +233,7 @@ class CORE_EXPORT QgsAbstractGeometry
 
     /** Returns the number of nodes contained in the geometry
      */
-    int nCoordinates() const;
+    virtual int nCoordinates() const;
 
     /** Returns the point corresponding to a specified vertex id
      */

src/core/geometry/qgscurvepolygon.cpp

@@ -632,6 +632,27 @@ QgsCoordinateSequence QgsCurvePolygon::coordinateSequence() const
   return mCoordinateSequence;
 }
 
+int QgsCurvePolygon::nCoordinates() const
+{
+  if ( !mCoordinateSequence.isEmpty() )
+    return QgsAbstractGeometry::nCoordinates();
+
+  int count = 0;
+
+  if ( mExteriorRing )
+  {
+    count += mExteriorRing->nCoordinates();
+  }
+
+  QList<QgsCurve*>::const_iterator it = mInteriorRings.constBegin();
+  for ( ; it != mInteriorRings.constEnd(); ++it )
+  {
+    count += ( *it )->nCoordinates();
+  }
+
+  return count;
+}
+
 double QgsCurvePolygon::closestSegment( const QgsPointV2& pt, QgsPointV2& segmentPt, QgsVertexId& vertexAfter, bool* leftOf, double epsilon ) const
 {
   if ( !mExteriorRing )

src/core/geometry/qgscurvepolygon.h

@@ -93,6 +93,7 @@ class CORE_EXPORT QgsCurvePolygon: public QgsSurface
     virtual bool deleteVertex( QgsVertexId position ) override;
 
     virtual QgsCoordinateSequence coordinateSequence() const override;
+    virtual int nCoordinates() const override;
     double closestSegment( const QgsPointV2& pt, QgsPointV2& segmentPt,  QgsVertexId& vertexAfter, bool* leftOf, double epsilon ) const override;
     bool nextVertex( QgsVertexId& id, QgsPointV2& vertex ) const override;
 

src/core/geometry/qgsgeometrycollection.cpp

@@ -369,6 +369,22 @@ QgsCoordinateSequence QgsGeometryCollection::coordinateSequence() const
   return mCoordinateSequence;
 }
 
+int QgsGeometryCollection::nCoordinates() const
+{
+  if ( !mCoordinateSequence.isEmpty() )
+    return QgsAbstractGeometry::nCoordinates();
+
+  int count = 0;
+
+  QVector< QgsAbstractGeometry* >::const_iterator geomIt = mGeometries.constBegin();
+  for ( ; geomIt != mGeometries.constEnd(); ++geomIt )
+  {
+    count += ( *geomIt )->nCoordinates();
+  }
+
+  return count;
+}
+
 double QgsGeometryCollection::closestSegment( const QgsPointV2& pt, QgsPointV2& segmentPt,  QgsVertexId& vertexAfter, bool* leftOf, double epsilon ) const
 {
   return QgsGeometryUtils::closestSegmentFromComponents( mGeometries, QgsGeometryUtils::PART, pt, segmentPt, vertexAfter, leftOf, epsilon );

src/core/geometry/qgsgeometrycollection.h

@@ -91,6 +91,8 @@ class CORE_EXPORT QgsGeometryCollection: public QgsAbstractGeometry
     virtual QgsRectangle boundingBox() const override;
 
     virtual QgsCoordinateSequence coordinateSequence() const override;
+    virtual int nCoordinates() const override;
+
     virtual double closestSegment( const QgsPointV2& pt, QgsPointV2& segmentPt,  QgsVertexId& vertexAfter, bool* leftOf, double epsilon ) const override;
     bool nextVertex( QgsVertexId& id, QgsPointV2& vertex ) const override;
 

src/core/geometry/qgslinestring.h

@@ -148,6 +148,7 @@ class CORE_EXPORT QgsLineString: public QgsCurve
     virtual QgsLineString* curveToLine( double tolerance = M_PI_2 / 90, SegmentationToleranceType toleranceType = MaximumAngle ) const override;
 
     int numPoints() const override;
+    virtual int nCoordinates() const override { return mX.size(); }
     void points( QgsPointSequence &pt ) const override;
 
     void draw( QPainter& p ) const override;

src/core/geometry/qgsmultipoint.h

@@ -40,6 +40,7 @@ class CORE_EXPORT QgsMultiPointV2: public QgsGeometryCollection
     QDomElement asGML3( QDomDocument& doc, int precision = 17, const QString& ns = "gml" ) const override;
     QString asJSON( int precision = 17 ) const override;
 
+    virtual int nCoordinates() const override { return mGeometries.size(); }
 
     //! Adds a geometry and takes ownership. Returns true in case of success
     virtual bool addGeometry( QgsAbstractGeometry* g ) override;

src/core/geometry/qgspointv2.h

@@ -170,6 +170,7 @@ class CORE_EXPORT QgsPointV2: public QgsAbstractGeometry
                     bool transformZ = false ) override;
     void transform( const QTransform& t ) override;
     virtual QgsCoordinateSequence coordinateSequence() const override;
+    virtual int nCoordinates() const override { return 1; }
     virtual QgsAbstractGeometry* boundary() const override;
 
     //low-level editing