# ID2D1Geometry::ComputePointAtLength methods

Calculates the point and tangent vector at the specified distance along the geometry.

MethodDescription
ComputePointAtLength(FLOAT,D2D1_MATRIX_3X2_F&,D2D1_POINT_2F*,D2D1_POINT_2F*)

Calculates the point and tangent vector at the specified distance along the geometry after it has been transformed by the specified matrix and flattened using the default tolerance.

ComputePointAtLength(FLOAT,D2D1_MATRIX_3X2_F*,D2D1_POINT_2F*,D2D1_POINT_2F*)

Calculates the point and tangent vector at the specified distance along the geometry after it has been transformed by the specified matrix and flattened using the default tolerance.

ComputePointAtLength(FLOAT,D2D1_MATRIX_3X2_F&,FLOAT,D2D1_POINT_2F*,D2D1_POINT_2F*)

Calculates the point and tangent vector at the specified distance along the geometry after it has been transformed by the specified matrix and flattened using the specified tolerance.

ComputePointAtLength(FLOAT,D2D1_MATRIX_3X2_F*,FLOAT,D2D1_POINT_2F*,D2D1_POINT_2F*)

Calculates the point and tangent vector at the specified distance along the geometry after it has been transformed by the specified matrix and flattened using the specified tolerance.

## Examples

The following code example shows how to use ComputePointAtLength to calculate the point and tangent vector at the specified distance along the geometry.

```
D2D1_POINT_2F point;
D2D1_POINT_2F tangent;

```
```
// Ask the geometry to give us the point that corresponds with the
// length at the current time.
hr = m_pPathGeometry->ComputePointAtLength(
length,
NULL,
&point,
&tangent);

```

## Requirements

 Library D2d1.lib D2d1.dll