LWGEOM_expand()

Datum LWGEOM_expand

(

PG_FUNCTION_ARGS

)

Definition at line 1602 of file lwgeom_functions_basic.c.

{
        GSERIALIZED *geom = PG_GETARG_GSERIALIZED_P(0);
        LWGEOM *lwgeom = lwgeom_from_gserialized(geom);
        int srid = lwgeom_get_srid(lwgeom);
        LWPOLY *poly;
        GSERIALIZED *result;
        GBOX gbox;
 
        POSTGIS_DEBUG(2, "LWGEOM_expand called.");
 
        /* Can't expand an empty */
        if ( lwgeom_is_empty(lwgeom) )
        {
                lwgeom_free(lwgeom);
                PG_RETURN_POINTER(geom);
        }
 
        /* Can't expand something with no gbox! */
        if ( LW_FAILURE == lwgeom_calculate_gbox(lwgeom, &gbox) )
        {
                lwgeom_free(lwgeom);
                PG_RETURN_POINTER(geom);
        }
 
        if (PG_NARGS() == 2)
        {
                /* Expand the box the same amount in all directions */
                double d = PG_GETARG_FLOAT8(1);
                gbox_expand(&gbox, d);
        }
        else
        {
                double dx = PG_GETARG_FLOAT8(1);
                double dy = PG_GETARG_FLOAT8(2);
                double dz = PG_GETARG_FLOAT8(3);
                double dm = PG_GETARG_FLOAT8(4);
 
                gbox_expand_xyzm(&gbox, dx, dy, dz, dm);
        }
 
        {
                POINT4D p1 = { gbox.xmin, gbox.ymin, gbox.zmin, gbox.mmin };
                POINT4D p2 = { gbox.xmin, gbox.ymax, gbox.zmin, gbox.mmin };
                POINT4D p3 = { gbox.xmax, gbox.ymax, gbox.zmax, gbox.mmax };
                POINT4D p4 = { gbox.xmax, gbox.ymin, gbox.zmax, gbox.mmax };
 
                poly = lwpoly_construct_rectangle(lwgeom_has_z(lwgeom), lwgeom_has_m(lwgeom), &p1, &p2, &p3, &p4);
        }
 
        lwgeom_add_bbox(lwpoly_as_lwgeom(poly));
        lwgeom_set_srid(lwpoly_as_lwgeom(poly), srid);
 
        /* Construct GSERIALIZED  */
        result = geometry_serialize(lwpoly_as_lwgeom(poly));
 
        lwgeom_free(lwpoly_as_lwgeom(poly));
        lwgeom_free(lwgeom);
        PG_FREE_IF_COPY(geom, 0);
 
        PG_RETURN_POINTER(result);
}

References gbox_expand(), gbox_expand_xyzm(), geometry_serialize(), LW_FAILURE, lwgeom_add_bbox(), lwgeom_calculate_gbox(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_get_srid(), lwgeom_has_m(), lwgeom_has_z(), lwgeom_is_empty(), lwgeom_set_srid(), lwpoly_as_lwgeom(), lwpoly_construct_rectangle(), GBOX::mmax, GBOX::mmin, GBOX::xmax, GBOX::xmin, GBOX::ymax, GBOX::ymin, GBOX::zmax, and GBOX::zmin.

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