point_in_polygon()

int point_in_polygon	(	LWPOLY *	polygon,
		LWPOINT *	point
	)

Definition at line 983 of file lwgeom_functions_analytic.c.

References getPoint2d_p(), LWPOLY::nrings, LWPOINT::point, point_in_ring(), and LWPOLY::rings.

Referenced by pip_short_circuit().

{
        int i, result, in_ring;
        POINT2D pt;

        POSTGIS_DEBUG(2, "point_in_polygon called.");

        getPoint2d_p(point->point, 0, &pt);
        /* assume bbox short-circuit has already been attempted */

        /* everything is outside of an empty polygon */
        if ( polygon->nrings == 0 ) return -1;

        in_ring = point_in_ring(polygon->rings[0], &pt);
        if ( in_ring == -1) /* outside the exterior ring */
        {
                POSTGIS_DEBUG(3, "point_in_polygon: outside exterior ring.");
                return -1;
        }
        result = in_ring;

        for (i=1; i<polygon->nrings; i++)
        {
                in_ring = point_in_ring(polygon->rings[i], &pt);
                if (in_ring == 1) /* inside a hole => outside the polygon */
                {
                        POSTGIS_DEBUGF(3, "point_in_polygon: within hole %d.", i);
                        return -1;
                }
                if (in_ring == 0) /* on the edge of a hole */
                {
                        POSTGIS_DEBUGF(3, "point_in_polygon: on edge of hole %d.", i);
                        return 0;
                }
        }
        return result; /* -1 = outside, 0 = boundary, 1 = inside */
}

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