ArcGIS Pro 2.8 API Reference Guide
ReflectAboutLine Method (GeometryEngine)
Example 

ArcGIS.Core.Geometry Namespace > GeometryEngine Class : ReflectAboutLine Method
The input geometry.
The reflection line.
Reflects the input geometry about the given line.
Syntax
public Geometry ReflectAboutLine( 
   Geometry geometry,
   LineSegment reflectionLine
)
Public Function ReflectAboutLine( _
   ByVal geometry As Geometry, _
   ByVal reflectionLine As LineSegment _
) As Geometry

Parameters

geometry
The input geometry.
reflectionLine
The reflection line.

Return Value

The reflected geometry.
Exceptions
ExceptionDescription
The input geometry or the reflection line is null.
The geometry is an envelope, and envelopes cannot be reflected.
Incompatible spatial references.
Remarks

GeometryEngine ReflectAboutLine

Example
SpatialReference sr = SpatialReferences.WGS84;

Coordinate2D start = new Coordinate2D(0, 0);
Coordinate2D end = new Coordinate2D(4, 4);
LineSegment line = LineBuilder.CreateLineSegment(start, end, sr);

Coordinate2D[] coords = new Coordinate2D[]
{
  new Coordinate2D(-1, 2),
  new Coordinate2D(-1, 4),
  new Coordinate2D(1, 4),
  new Coordinate2D(-1, 2)
};

Polygon polygon = PolygonBuilder.CreatePolygon(coords, sr);

// reflect a polygon about the line
Polygon reflectedPolygon = GeometryEngine.Instance.ReflectAboutLine(polygon, line) as Polygon;

// reflectedPolygon points are 
//    (2, -1), (4, -1), (4, 1), (2, -1)
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

GeometryEngine Class
GeometryEngine Members