geometry_line_extend()

Datum geometry_line_extend

(

PG_FUNCTION_ARGS

)

Definition at line 2655 of file lwgeom_functions_basic.c.

{
        GSERIALIZED *geom1, *geom2;
        LWLINE *lwline1, *lwline2;
        LWGEOM *lwgeom1, *lwgeom2;
        double distance_forward, distance_backward;
 
        geom1 = PG_GETARG_GSERIALIZED_P(0);
        distance_forward = PG_GETARG_FLOAT8(1);
        distance_backward = PG_GETARG_FLOAT8(2);
 
        lwgeom1 = lwgeom_from_gserialized(geom1);
        lwline1 = lwgeom_as_lwline(lwgeom1);
        if (!lwline1)
                lwpgerror("Argument must be LINESTRING geometry");
 
        if (lwline_is_empty(lwline1))
                PG_RETURN_NULL();
 
        if (lwline_length_2d(lwline1) <= 0.0)
                PG_RETURN_POINTER(geom1);
 
        lwline2 = lwline_extend(lwline1, distance_forward, distance_backward);
        lwgeom2 = lwline_as_lwgeom(lwline2);
        geom2 = geometry_serialize(lwgeom2);
 
        PG_RETURN_POINTER(geom2);
}

References lwgeom_as_lwline(), lwgeom_from_gserialized(), lwline_as_lwgeom(), lwline_extend(), lwline_is_empty(), and lwline_length_2d().

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