# esriSegmentExtension Constants

Describes if, how, and where to extend segments.

Constant Value Description
esriNoExtension 0 The segment is not extended.
esriExtendTangentAtFrom 1 The segment is extended infinitely far along the line tangent to its 'from' point.
esriExtendEmbeddedAtFrom 2 The segment is extended by producing its embedding geometry at its 'from' point (an arc segment's embedding geometry is a complete circle; a line segment's embedding geometry is an infinite line).
esriExtendTangentAtTo 4 The segment is extended infinitely far along the line tangent to its 'to' point.
esriExtendEmbeddedAtTo 8 The segment is extended by producing its embedding geometry at its 'to' point (an arc segment's embedding geometry is a complete circle; a line segment's embedding geometry is an infinite line).
esriExtendTangents 5 The segment is extended infinitely far along lines tangent to both endpoints.
esriExtendEmbedded 10 The segment is extended by producing its embedding geometry at both endpoints (an arc segment's embedding geometry is a complete circle; a line segment's embedding geometry is an infinite line).
esriExtendAtFrom 3 The segment is extended at its 'from' point, either by tangent or by its embedding geometry.
esriExtendAtTo 12 The segment is extended at its 'to' point, either by tangent or by its embedding geometry.

## Remarks

Determines how a segment is to be extended, and from where that extension is to take place. Extension can occur at any specified point along the curve. Extension from the From point occurs at a negative length from the curve, and extension from the To Point occurs at a positive length from the curve. Tangential extension extends an infinite line from the specified point in the direction of the tangent at that point. Embedded extension extends the curve as a continuation of the shape of the curve. For Lines, tangential and embedded extension produce the same results. Embedded extension completes Circular and Elliptic Arcs. Circular and Elliptic Arcs can also be extended tangentially from either endpoint. Bezier curves only support tangential extension. Extension enumerations esriExtendAtFrom and esriExtendAtTo are only used to check the extension type and are not valid input extension methods.

``````esriExtendTangents  = esriExtendTangentAtFrom And/Or esriExtendTangentAtTo
esriExtendEmbedded  = esriExtendEmbeddedAtFrom And/Or esriExtendEmbeddedAtTo
esriExtendAtFrom    = esriExtendTangentAtFrom Or esriExtendEmbeddedAtFrom
esriExtendAtTo      = esriExtendTangentAtTo Or esriExtendEmbeddedAtTo
`````` 