### astTran1

Transform 1-dimensional coordinates

#### Description:

This function applies a Mapping to transform the coordinates of a set of points in one dimension.

#### Synopsis

void astTran1( AstMapping $\ast$this, int npoint, const double xin[], int forward, double xout[] )

#### Parameters:

##### this
Pointer to the Mapping to be applied.
##### npoint
The number of points to be transformed.
##### xin
An array of " npoint" coordinate values for the input (untransformed) points.
##### forward
A non-zero value indicates that the Mapping’ s forward coordinate transformation is to be applied, while a zero value indicates that the inverse transformation should be used.
##### xout
An array (with " npoint" elements) into which the coordinates of the output (transformed) points will be written.

#### Notes:

• The Mapping supplied must have the value 1 for both its Nin and Nout attributes.

#### Handling of Huge Pixel Arrays

If the number of points to be transformed exceeds the largest value that can be represented by a 4-byte integer, then the alternative " 8-byte" interface for this function should be used. This alternative interface uses 8 byte integer arguments (instead of 4-byte). Specifically, the argument " npoint" , is changed from type " int" to type " int64_t" (defined in header file stdint.h). The function name is changed by appending the digit " 8" to the name. Thus, astTran1 becomes astTran18