geometry_to_polygon()

Datum geometry_to_polygon

(

PG_FUNCTION_ARGS

)

Definition at line 192 of file geometry_inout.c.

{
        POLYGON *polygon;
        LWPOLY *lwpoly;
        LWGEOM *lwgeom;
        GSERIALIZED *geom;
        POINTARRAY *pa;
        GBOX gbox;
        uint32_t i;
        size_t size;
 
        POSTGIS_DEBUG(2, "geometry_to_polygon called");
 
        if ( PG_ARGISNULL(0) )
                PG_RETURN_NULL();
 
        geom = PG_GETARG_GSERIALIZED_P(0);
 
        if ( gserialized_get_type(geom) != POLYGONTYPE )
                elog(ERROR, "geometry_to_polygon only accepts Polygons");
 
        lwgeom = lwgeom_from_gserialized(geom);
        if ( lwgeom_is_empty(lwgeom) )
                PG_RETURN_NULL();
        lwpoly = lwgeom_as_lwpoly(lwgeom);
 
        pa = lwpoly->rings[0];
 
        size = offsetof(POLYGON, p[0]) + sizeof(polygon->p[0]) * pa->npoints;
        polygon = (POLYGON*)palloc0(size); /* zero any holes */
        SET_VARSIZE(polygon, size);
 
        polygon->npts = pa->npoints;
 
        lwgeom_calculate_gbox(lwgeom, &gbox);
        polygon->boundbox.low.x = gbox.xmin;
        polygon->boundbox.low.y = gbox.ymin;
        polygon->boundbox.high.x = gbox.xmax;
        polygon->boundbox.high.y = gbox.ymax;
 
        for ( i = 0; i < pa->npoints; i++ )
        {
                const POINT2D *pt = getPoint2d_cp(pa, i);
                (polygon->p[i]).x = pt->x;
                (polygon->p[i]).y = pt->y;
        }
 
        lwgeom_free(lwgeom);
        PG_FREE_IF_COPY(geom,0);
 
        PG_RETURN_POLYGON_P(polygon);
}

References getPoint2d_cp(), gserialized_get_type(), lwgeom_as_lwpoly(), lwgeom_calculate_gbox(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_is_empty(), POINTARRAY::npoints, POLYGONTYPE, LWPOLY::rings, POINT2D::x, pixval::x, GBOX::xmax, GBOX::xmin, POINT2D::y, GBOX::ymax, and GBOX::ymin.

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