VARKON Version 1.15 1997-10-24

inv_tang - Function

Geometrical function


Description

Returns the parameter value of a position on an arc or curve having a specified tangent direction.

Syntax

inv_tang(ref, tan, alt)

REF	ref;
VECTOR	tan;
INT	alt;

Principal parameters

ref	- Identity of arc or curve
tan	- Requested tangent direction

Optional parameters

alt	- Alternative, default = 1

Return value

A FLOAT value equal to the parameter value of the requested position.

Example

INV_TANG(#5,vec(1,0))

The parameter value of a position on #5 where its tangent direction is equal to the direction of X=1, Y=0.

Comments

If more than one position on the entity has the specified tangent direction alt can be used to select the right one.