initial commit

Author: lbartoletti

resources/function_help/json/minimal_circle

@@ -0,0 +1,10 @@
+{
+  "name": "minimal_circle",
+  "type": "function",
+  "description": "Returns the minimal enclosing circle of a geometry. It represents the minimum circle that encloses all geometries within the set.",
+  "arguments": [ {"arg":"geometry","description":"a geometry"},
+                 {"arg":"segment", "description": "optional argument for polygon segmentation. By default this value is 36"}],
+  "examples": [ { "expression":"geom_to_wkt( minimal_circle( geom_from_wkt( 'LINESTRING(0 5, 0 -5, 2 1)' ), 4 ) )", "returns":"Polygon ((0 5, 5 -0, -0 -5, -5 0, 0 5))"},
+  { "expression":"geom_to_wkt( minimal_circle( geom_from_wkt( 'MULTIPOINT(1 2, 3 4, 3 2)' ), 4 ) )", "returns":"Polygon ((3 4, 3 2, 1 2, 1 4, 3 4))"}
+  ]
+}

resources/function_help/json/oriented_bbox

@@ -0,0 +1,8 @@
+{
+  "name": "oriented_bbox",
+  "type": "function",
+  "description":"Returns a geometry which represents the minimal oriented bounding box of an input geometry.",
+  "arguments": [ {"arg":"geom","description":"a geometry"} ],
+  "examples": [ { "expression":"geom_to_wkt( oriented_bbox( geom_from_wkt( 'MULTIPOINT(1 2, 3 4, 3 2)' ) ) )", "returns":"Polygon ((1 4, 1 2, 3 2, 3 4, 1 4))"}]
+}
+

src/core/expression/qgsexpressionfunction.cpp

@@ -2535,6 +2535,29 @@ static QVariant fcnConvexHull( const QVariantList &values, const QgsExpressionCo
   QVariant result = !geom.isNull() ? QVariant::fromValue( geom ) : QVariant();
   return result;
 }
+
+static QVariant fcnMinimalCircle( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent )
+{
+  QgsGeometry fGeom = QgsExpressionUtils::getGeometry( values.at( 0 ), parent );
+  QgsPointXY center;
+  double radius;
+  unsigned int segments = 36;
+  if ( values.length() == 2 )
+    segments = QgsExpressionUtils::getDoubleValue( values.at( 1 ), parent );
+  QgsGeometry geom = fGeom.minimalEnclosingCircle( center, radius, segments );
+  QVariant result = !geom.isNull() ? QVariant::fromValue( geom ) : QVariant();
+  return result;
+}
+
+static QVariant fcnOrientedBBox( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent )
+{
+  QgsGeometry fGeom = QgsExpressionUtils::getGeometry( values.at( 0 ), parent );
+  double area, angle, width, height;
+  QgsGeometry geom = fGeom.orientedMinimumBoundingBox( area, angle, width, height );
+  QVariant result = !geom.isNull() ? QVariant::fromValue( geom ) : QVariant();
+  return result;
+}
+
 static QVariant fcnDifference( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent )
 {
   QgsGeometry fGeom = QgsExpressionUtils::getGeometry( values.at( 0 ), parent );
@@ -4139,6 +4162,13 @@ const QList<QgsExpressionFunction *> &QgsExpression::Functions()
         << new QgsStaticExpressionFunction( QStringLiteral( "bounds_height" ), 1, fcnBoundsHeight, QStringLiteral( "GeometryGroup" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "is_closed" ), 1, fcnIsClosed, QStringLiteral( "GeometryGroup" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "convex_hull" ), 1, fcnConvexHull, QStringLiteral( "GeometryGroup" ), QString(), false, QSet<QString>(), false, QStringList() << QStringLiteral( "convexHull" ) )
+        << new QgsStaticExpressionFunction( QStringLiteral( "oriented_bbox" ), QgsExpressionFunction::ParameterList()
+                                            << QgsExpressionFunction::Parameter( QStringLiteral( "geometry" ) ),
+                                            fcnOrientedBBox, QStringLiteral( "GeometryGroup" ) )
+        << new QgsStaticExpressionFunction( QStringLiteral( "minimal_circle" ), QgsExpressionFunction::ParameterList()
+                                            << QgsExpressionFunction::Parameter( QStringLiteral( "geometry" ) )
+                                            << QgsExpressionFunction::Parameter( QStringLiteral( "segments" ), true, 36 ),
+                                            fcnMinimalCircle, QStringLiteral( "GeometryGroup" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "difference" ), 2, fcnDifference, QStringLiteral( "GeometryGroup" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "distance" ), 2, fcnDistance, QStringLiteral( "GeometryGroup" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "hausdorff_distance" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "geometry1" ) ) << QgsExpressionFunction::Parameter( QStringLiteral( "geometry2" ) )

tests/src/core/testqgsexpression.cpp

@@ -2302,6 +2302,14 @@ class TestQgsExpression: public QObject
       geom = QgsGeometry::fromPolygon( polygon );
       QTest::newRow( "bounds" ) << "bounds( $geometry )" << geom << false << true << QgsGeometry::fromRect( geom.boundingBox() );
 
+      geom = QgsGeometry::fromPolygon( polygon );
+      double bbox_area, bbox_angle, bbox_width, bbox_height;
+      QTest::newRow( "oriented_bbox" ) << "oriented_bbox( $geometry )" << geom << false << true << geom.orientedMinimumBoundingBox( bbox_area, bbox_angle, bbox_width, bbox_height );
+      geom = QgsGeometry::fromPolygon( polygon );
+      QgsPointXY circ_center;
+      double circ_radius;
+      QTest::newRow( "minimal_circle" ) << "minimal_circle( $geometry )" << geom << false << true << geom.minimalEnclosingCircle( circ_center, circ_radius );
+
       geom = QgsGeometry::fromPolygon( polygon );
       QTest::newRow( "translate" ) << "translate( $geometry, 1, 2)" << geom << false << true << QgsGeometry::fromWkt( QStringLiteral( "POLYGON ((1 2,11 12,11 2,1 2))" ) );
       geom = QgsGeometry::fromPolyline( line );