polygon_to_geometry()

Datum polygon_to_geometry

(

PG_FUNCTION_ARGS

)

Definition at line 247 of file geometry_inout.c.

{
        POLYGON *polygon;
        LWPOLY *lwpoly;
        POINTARRAY *pa;
        POINTARRAY **ppa;
        GSERIALIZED *geom;
        Point p;
        int i = 0, unclosed = 0;
 
        POSTGIS_DEBUG(2, "polygon_to_geometry called");
 
        if ( PG_ARGISNULL(0) )
                PG_RETURN_NULL();
 
        polygon = PG_GETARG_POLYGON_P(0);
 
        if ( ! polygon )
                PG_RETURN_NULL();
 
        /* Are first and last points different? If so we need to close this ring */
        if ( memcmp( polygon->p, polygon->p + polygon->npts - 1, sizeof(Point) ) )
        {
                unclosed = 1;
        }
 
        pa = ptarray_construct_empty(0, 0, polygon->npts + unclosed);
 
        for ( i = 0; i < (polygon->npts+unclosed); i++ )
        {
                POINT4D pt;
                p = polygon->p[i % polygon->npts];
                pt.x = p.x;
                pt.y = p.y;
                ptarray_append_point(pa, &pt, LW_FALSE);
        }
 
        ppa = palloc(sizeof(POINTARRAY*));
        ppa[0] = pa;
        lwpoly = lwpoly_construct(SRID_UNKNOWN, NULL, 1, ppa);
        geom = geometry_serialize(lwpoly_as_lwgeom(lwpoly));
        lwpoly_free(lwpoly);
 
        PG_RETURN_POINTER(geom);
}

References geometry_serialize(), LW_FALSE, lwpoly_as_lwgeom(), lwpoly_construct(), lwpoly_free(), ptarray_append_point(), ptarray_construct_empty(), SRID_UNKNOWN, POINT4D::x, struct_point::x, POINT4D::y, and struct_point::y.

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