ArcGIS Pro 2.7 API Reference Guide
EllipticArcBuilder Constructor(Coordinate2D,Double,Double,Double,esriArcOrientation,SpatialReference)
Example 

ArcGIS.Core.Geometry Namespace > EllipticArcBuilder Class > EllipticArcBuilder Constructor : EllipticArcBuilder Constructor(Coordinate2D,Double,Double,Double,esriArcOrientation,SpatialReference)
The center point of the ellipse.
The angle in radians by which the ellipse is rotated from the x-axis. A positive value corresponds to counterclockwise rotation.
The length of the semi-major axis.
The ratio of the length of the semi-minor axis to the length of the semi-major axis.
The orientation of the arc, clockwise or counterclockwise.
(Optional) The spatial reference of the arc. The default value is null.
Builds a new instance of the EllipticArcBuilder class. The new instance will be an ellipse. This method must be called on the MCT. Use QueuedTask.Run.
Syntax

Parameters

centerPt
The center point of the ellipse.
rotationAngle
The angle in radians by which the ellipse is rotated from the x-axis. A positive value corresponds to counterclockwise rotation.
semiMajorAxis
The length of the semi-major axis.
minorMajorRatio
The ratio of the length of the semi-minor axis to the length of the semi-major axis.
orientation
The orientation of the arc, clockwise or counterclockwise.
spatialReference
(Optional) The spatial reference of the arc. The default value is null.
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
Example
// Construct an ellipse centered at (1, 2) with rotationAngle = -pi/6,  
// semiMajorAxis = 5, minorMajorRatio = 0.2, oriented clockwise.
// Use a builder convenience method or use a builder constructor.

Coordinate2D centerPt = new Coordinate2D(1, 2);

// Builder convenience methods don't need to run on the MCT.
EllipticArcSegment ellipse = EllipticArcBuilder.CreateEllipticArcSegment(centerPt, -1 * Math.PI / 6, 5, 0.2, esriArcOrientation.esriArcClockwise);

// Builder constructors need to run on the MCT.
ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
{
  using (EllipticArcBuilder builder = new EllipticArcBuilder(centerPt, -1 * Math.PI / 6, 5, 0.2, esriArcOrientation.esriArcClockwise))
  {
    // do something with the builder

    EllipticArcSegment anotherEllipse = builder.ToSegment();
  }
});
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

EllipticArcBuilder Class
EllipticArcBuilder Members
Overload List