# CurveTangent Enumeration

Specifies different tangent types to be calculated for CurveKey points in a Curve.

Namespace:  Microsoft.Xna.Framework
Assembly:  Microsoft.Xna.Framework.Math (in Microsoft.Xna.Framework.Math.dll)

## Syntax

```public enum CurveTangent
```

### Members

Member nameDescription
FlatA Flat tangent always has a value equal to zero.
LinearA Linear tangent at a CurveKey is equal to the difference between its Value and the value of the preceding or succeeding CurveKey.
SmoothA Smooth tangent smooths the inflection between a TangentIn and TangentOut by taking into account the values of both neighbors of the CurveKey.

## Remarks

A Linear tangent at a CurveKey is equal to the difference between its Value and the value of the preceding or succeeding CurveKey.

For example, in Curve MyCurve, where i is greater than zero and (i + 1) is less than the total number of CurveKey instances in MyCurve, the linear TangentIn of MyCurve.Keys[i] is equal to:

( MyCurve.Keys[i].Value - MyCurve.Keys[i - 1].Value )

Similarly, the linear TangentOut is equal to:

( MyCurve.Keys[i + 1].Value - MyCurve.Keys[i].Value.)

A Smooth tangent smooths the inflection between a TangentIn and TangentOut by taking into account the values of both neighbors of the CurveKey.

The smooth TangentIn of MyCurve.Keys[i] is equal to:

( ( MyCurve.Keys[i + 1].Value - MyCurve.Keys[i - 1].Value ) *

( ( MyCurve.Keys[i].Position - MyCurve.Keys[i - 1].Position ) /

( MyCurve.Keys[i + 1].Position - MyCurve.Keys[i-1].Position ) ) )

Similarly, the smooth TangentOut is equal to:

( ( MyCurve.Keys[i + 1].Value - MyCurve.Keys[i - 1].Value ) *

( ( MyCurve.Keys[i + 1].Position - MyCurve.Keys[i].Position ) /

( MyCurve.Keys[i + 1].Position - MyCurve.Keys[i - 1].Position ) ) )

Supported in: 5

## Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.