LWGEOM_exteriorring_polygon()

Datum LWGEOM_exteriorring_polygon

(

PG_FUNCTION_ARGS

)

Definition at line 474 of file lwgeom_ogc.c.

{
        GSERIALIZED *geom = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *result;
        POINTARRAY *extring;
        LWGEOM *lwgeom = lwgeom_from_gserialized(geom);
        LWLINE *line;
        GBOX *bbox=NULL;
 
        if ( ! lwgeom_has_rings(lwgeom) )
                PG_RETURN_NULL();
 
        if( lwgeom_is_empty(lwgeom) )
        {
                line = lwline_construct_empty(lwgeom->srid,
                                              lwgeom_has_z(lwgeom),
                                              lwgeom_has_m(lwgeom));
                result = geometry_serialize(lwline_as_lwgeom(line));
        }
        else if ( lwgeom->type == POLYGONTYPE )
        {
                LWPOLY *poly = lwgeom_as_lwpoly(lwgeom);
 
                /* Ok, now we have a polygon. Here is its exterior ring. */
                extring = poly->rings[0];
 
                /*
                * This is a LWLINE constructed by exterior ring POINTARRAY
                * If the input geom has a bbox, use it for
                * the output geom, as exterior ring makes it up !
                */
                if ( poly->bbox )
                        bbox = gbox_copy(poly->bbox);
 
                line = lwline_construct(poly->srid, bbox, extring);
                result = geometry_serialize((LWGEOM *)line);
 
                lwgeom_release((LWGEOM *)line);
        }
        else if ( lwgeom->type == TRIANGLETYPE )
        {
                LWTRIANGLE *triangle = lwgeom_as_lwtriangle(lwgeom);
 
                /*
                * This is a LWLINE constructed by exterior ring POINTARRAY
                * If the input geom has a bbox, use it for
                * the output geom, as exterior ring makes it up !
                */
                if ( triangle->bbox )
                        bbox = gbox_copy(triangle->bbox);
                line = lwline_construct(triangle->srid, bbox, triangle->points);
 
                result = geometry_serialize((LWGEOM *)line);
 
                lwgeom_release((LWGEOM *)line);
        }
        else
        {
                LWCURVEPOLY *curvepoly = lwgeom_as_lwcurvepoly(lwgeom);
                result = geometry_serialize(curvepoly->rings[0]);
        }
 
        lwgeom_free(lwgeom);
        PG_FREE_IF_COPY(geom, 0);
        PG_RETURN_POINTER(result);
}

References LWTRIANGLE::bbox, LWPOLY::bbox, gbox_copy(), lwgeom_as_lwcurvepoly(), lwgeom_as_lwpoly(), lwgeom_as_lwtriangle(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_has_m(), lwgeom_has_rings(), lwgeom_has_z(), lwgeom_is_empty(), lwgeom_release(), lwline_as_lwgeom(), lwline_construct(), lwline_construct_empty(), LWTRIANGLE::points, POLYGONTYPE, result, LWPOLY::rings, LWCURVEPOLY::rings, LWGEOM::srid, LWTRIANGLE::srid, LWPOLY::srid, TRIANGLETYPE, and LWGEOM::type.

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