GEOtestPointOnLine

Examination whether a point on a line lies.

This function checks whether a point on lies by starting point and terminator point given line or her lengthening.

Parametre

STAND-IN x, y [IN]

Co-ordinates of the point to be tested

STAND-IN x1, y1, x2, y2 [IN]

Starting point and terminator point of the line

Result

int OUT

0 Sharp lies on the line between both points

-1 Sharp lies on the lengthening of the line

-2 Sharp does not lie on the line.

Declaration

#include "basic.h“

int DLLENTRY GEOtestPointOnLine (

STAND-IN x,

STAND-IN y,

STAND-IN x1,

STAND-IN y1,

STAND-IN x2,

STAND-IN y2

);

Example

status = GEOtestPointOnLine (50.0, 50.0, 20.0, 20.0, 150.0, 150.0)

The function delivers the value 0, i.e. the point lies on the line.

status = GEOtestPointOnLine (10.0, 10.0, 20.0, 20.0, 150.0, 150.0)

The function delivers the value-1, i.e. the point lies on the lengthening of the line.