# Synopsis

PDX_MSGT mth_Intersect2DLines(long option, double para_tol, double *pt1, double *tan1, double *pt2, double *tan2, double *alf1, double *alf2, double *intpt)

# Purpose

Intersect two parametric lines in the xy-plane.

# Description

This routine intersects two parametric straight lines lying in the xy-plane. The lines must be in point/vector form.

# Input

## option

### MTH_ALPHAS

Just compute alf1 and alf2 (see below).

### MTH_POINT

Just compute the intersection point.

## para_tol

The parallel lines test tolerances.

## pt1

The initial point on the first line (array with two elements).

## tan1

The tangent vector of the first line.

## pt2

The initial point on the second line.

## tan2

The tangent vector of the second line.

# Output

## alf1

Parametric distance of intersection point from pt1 along tan1 ( option must be set to MTH_ALPHAS).

## alf2

Parametric distance of intersection point from pt2 along tan2 ( option must be set to MTH_ALPHAS ).

## intpt

The intersection point (array with x,y-coordinates). ( option must be set to MTH_POINT ).

# Return

          MTH_NOERR
          MTH_PARALLELLINES
          .fi