Merge pull request #1744 from rldhont/expression_get_transform_geom

[FEATURE] Add get and trasnform geometry in Expression

Author: NathanW2

resources/function_help/geometry

@@ -0,0 +1,12 @@
+<h3>getGeometry function</h3>
+Returns the feature's geometry
+
+<h4>Syntax</h4>
+<pre>geometry( f )</pre>
+
+<h4>Arguments</h4>
+f &rarr; QgsFeature
+
+<h4>Example</h4>
+<pre> geomToWKT( geometry( getFeature( layer, attributeField, value ) ) ) &rarr; POINT(6 50)</pre>
+<pre> intersects( $geometry, geometry( getFeature( layer, attributeField, value ) ) ) &rarr; 1</pre>

resources/function_help/transform

@@ -0,0 +1,15 @@
+<h3>transformGeometry function</h3>
+Returns the geometry transforms from the source CRS to the dest CRS.
+
+<h4>Syntax</h4>
+<pre>transform( geom, sAuthId, dAuthId )</pre>
+
+<h4>Arguments</h4>
+geom &rarr; QgsGeometry
+
+sCrsId &rarr; the Source Auth CRS Id
+
+dCrsId &rarr; the Dest Auth CRS Id
+
+<h4>Example</h4>
+<pre> geomToWKT( transform( $geometry, 'EPSG:2154', 'EPSG:4326' ) ) &rarr; POINT(0 51)</pre>

src/core/qgsexpression.cpp

@@ -1298,8 +1298,14 @@ static QVariant fcnCombine( const QVariantList& values, const QgsFeature*, QgsEx
 }
 static QVariant fcnGeomToWKT( const QVariantList& values, const QgsFeature*, QgsExpression* parent )
 {
+  if ( values.length() < 1 || values.length() > 2 )
+    return QVariant();
+    
   QgsGeometry fGeom = getGeometry( values.at( 0 ), parent );
-  QString wkt = fGeom.exportToWkt();
+  int prec = 8;
+  if ( values.length() == 2 )
+    prec = getIntValue( values.at( 1 ), parent );
+  QString wkt = fGeom.exportToWkt( prec );
   return QVariant( wkt );
 }
 
@@ -1546,6 +1552,34 @@ static QVariant fcnSpecialColumn( const QVariantList& values, const QgsFeature*
   return QgsExpression::specialColumn( varName );
 }
 
+static QVariant fcnGetGeometry( const QVariantList& values, const QgsFeature*, QgsExpression* parent )
+{
+  QgsFeature feat = getFeature( values.at( 0 ), parent );
+  QgsGeometry* geom = feat.geometry();
+  if ( geom )
+    return QVariant::fromValue( *geom );
+  return QVariant();
+}
+
+static QVariant fcnTransformGeometry( const QVariantList& values, const QgsFeature*, QgsExpression* parent )
+{
+  QgsGeometry fGeom = getGeometry( values.at( 0 ), parent );
+  QString sAuthId = getStringValue( values.at( 1 ), parent );
+  QString dAuthId = getStringValue( values.at( 2 ), parent );
+  
+  QgsCoordinateReferenceSystem s;
+  if ( ! s.createFromOgcWmsCrs( sAuthId ) )
+    return QVariant::fromValue( fGeom );
+  QgsCoordinateReferenceSystem d;
+  if ( ! d.createFromOgcWmsCrs( dAuthId ) )
+    return QVariant::fromValue( fGeom );
+    
+  QgsCoordinateTransform t( s, d );
+  if ( fGeom.transform( t ) == 0 )
+    return QVariant::fromValue( fGeom );
+  return QVariant();
+}
+
 static QVariant fcnGetFeature( const QVariantList& values, const QgsFeature *, QgsExpression* parent )
 {
   //arguments: 1. layer id / name, 2. key attribute, 3. eq value
@@ -1765,7 +1799,9 @@ const QList<QgsExpression::Function*> &QgsExpression::Functions()
     << new StaticFunction( "symDifference", 2, fcnSymDifference, "Geometry" )
     << new StaticFunction( "combine", 2, fcnCombine, "Geometry" )
     << new StaticFunction( "union", 2, fcnCombine, "Geometry" )
-    << new StaticFunction( "geomToWKT", 1, fcnGeomToWKT, "Geometry" )
+    << new StaticFunction( "geomToWKT", -1, fcnGeomToWKT, "Geometry" )
+    << new StaticFunction( "geometry", 1, fcnGetGeometry, "Geometry" )
+    << new StaticFunction( "transform", 3, fcnTransformGeometry, "Geometry" )
     << new StaticFunction( "$rownum", 0, fcnRowNumber, "Record" )
     << new StaticFunction( "$id", 0, fcnFeatureId, "Record" )
     << new StaticFunction( "$currentfeature", 0, fcnFeature, "Record" )

tests/src/core/testqgsexpression.cpp

@@ -745,6 +745,37 @@ class TestQgsExpression: public QObject
       QVariant vYMax = exp9.evaluate( &fPolygon );
       QCOMPARE( vYMax.toDouble(), 6.0 );
     }
+    
+    void eval_geometry_wkt()
+    {
+      QgsPolyline polyline, polygon_ring;
+      polyline << QgsPoint( 0, 0 ) << QgsPoint( 10, 0 );
+      polygon_ring << QgsPoint( 2, 1 ) << QgsPoint( 10, 1 ) << QgsPoint( 10, 6 ) << QgsPoint( 2, 6 ) << QgsPoint( 2, 1 );
+      
+      QgsPolygon polygon;
+      polygon << polygon_ring;
+      
+      QgsFeature fPoint, fPolygon, fPolyline;
+      fPoint.setGeometry( QgsGeometry::fromPoint( QgsPoint( -1.23456789, 9.87654321 ) ) );
+      fPolyline.setGeometry( QgsGeometry::fromPolyline( polyline ) );
+      fPolygon.setGeometry( QgsGeometry::fromPolygon( polygon ) );
+      
+      QgsExpression exp1( "geomToWKT($geometry)" );
+      QVariant vWktLine = exp1.evaluate( &fPolyline );
+      QCOMPARE( vWktLine.toString(), QString( "LINESTRING(0 0, 10 0)" ) );
+      
+      QgsExpression exp2( "geomToWKT($geometry)" );
+      QVariant vWktPolygon = exp2.evaluate( &fPolygon );
+      QCOMPARE( vWktPolygon.toString(), QString( "POLYGON((2 1,10 1,10 6,2 6,2 1))" ) );
+      
+      QgsExpression exp3( "geomToWKT($geometry)" );
+      QVariant vWktPoint = exp3.evaluate( &fPoint );
+      QCOMPARE( vWktPoint.toString(), QString( "POINT(-1.23456789 9.87654321)" ) );
+      
+      QgsExpression exp4( "geomToWKT($geometry, 3)" );
+      QVariant vWktPointSimplify = exp4.evaluate( &fPoint );
+      QCOMPARE( vWktPointSimplify.toString(), QString( "POINT(-1.235 9.877)" ) );
+    }
 
     void eval_geometry_constructor_data()
     {
@@ -803,6 +834,64 @@ class TestQgsExpression: public QObject
       QgsGeometry outGeom = out.value<QgsGeometry>();
       QCOMPARE( geom->equals( &outGeom ), true );
     }
+    
+    void eval_geometry_access_transform_data()
+    {
+      QTest::addColumn<QString>( "string" );
+      QTest::addColumn<void*>( "geomptr" );
+      QTest::addColumn<bool>( "evalError" );
+
+      QgsPoint point( 123, 456 );
+      QgsPolyline line;
+      line << QgsPoint( 1, 1 ) << QgsPoint( 4, 2 ) << QgsPoint( 3, 1 );
+
+      QgsPolyline polyline, polygon_ring;
+      polyline << QgsPoint( 0, 0 ) << QgsPoint( 10, 0 );
+      polygon_ring << QgsPoint( 1, 1 ) << QgsPoint( 6, 1 ) << QgsPoint( 6, 6 ) << QgsPoint( 1, 6 ) << QgsPoint( 1, 1 );
+      QgsPolygon polygon;
+      polygon << polygon_ring;
+
+      QTest::newRow( "geometry Point" ) << "geometry( $currentfeature )" << ( void* ) QgsGeometry::fromPoint( point ) << false;
+      QTest::newRow( "geometry Line" ) << "geometry( $currentfeature )" << ( void* ) QgsGeometry::fromPolyline( line ) << false;
+      QTest::newRow( "geometry Polyline" ) << "geometry( $currentfeature )" << ( void* ) QgsGeometry::fromPolyline( polyline ) << false;
+      QTest::newRow( "geometry Polygon" ) << "geometry( $currentfeature )" << ( void* ) QgsGeometry::fromPolygon( polygon ) << false;
+      
+      QgsCoordinateReferenceSystem s;
+      s.createFromOgcWmsCrs( "EPSG:4326" );
+      QgsCoordinateReferenceSystem d;
+      d.createFromOgcWmsCrs( "EPSG:3857" );
+      QgsCoordinateTransform t( s, d );
+      
+      QgsGeometry* tLine = QgsGeometry::fromPolyline( line );
+      tLine->transform( t );
+      QgsGeometry* tPolygon = QgsGeometry::fromPolygon( polygon );
+      tPolygon->transform( t );
+      
+      QTest::newRow( "transform Line" ) << "transform( geomFromWKT('" + QgsGeometry::fromPolyline( line )->exportToWkt() + "'), 'EPSG:4326', 'EPSG:3857' )" << ( void* ) tLine << false;
+      QTest::newRow( "transform Polygon" ) << "transform( geomFromWKT('" + QgsGeometry::fromPolygon( polygon )->exportToWkt() + "'), 'EPSG:4326', 'EPSG:3857' )" << ( void* ) tPolygon << false;
+    }
+
+    void eval_geometry_access_transform()
+    {
+      QFETCH( QString, string );
+      QFETCH( void*, geomptr );
+      QFETCH( bool, evalError );
+
+      QgsGeometry* geom = ( QgsGeometry* ) geomptr;
+
+      QgsFeature f;
+      f.setGeometry( geom );
+
+      QgsExpression exp( string );
+      QCOMPARE( exp.hasParserError(), false );
+      QCOMPARE( exp.needsGeometry(), false );
+      QVariant out = exp.evaluate( &f );
+      QCOMPARE( exp.hasEvalError(), evalError );
+
+      QCOMPARE( out.canConvert<QgsGeometry>(), true );
+      QgsGeometry outGeom = out.value<QgsGeometry>();
+      QCOMPARE( geom->equals( &outGeom ), true );
+    }
 
     void eval_spatial_operator_data()
     {