ST_MinimumBoundingRadius()

Datum ST_MinimumBoundingRadius

(

PG_FUNCTION_ARGS

)

Definition at line 1109 of file lwgeom_functions_analytic.c.

{
        GSERIALIZED* geom;
        LWGEOM* input;
        LWBOUNDINGCIRCLE* mbc = NULL;
        LWGEOM* lwcenter;
        GSERIALIZED* center;
        TupleDesc resultTupleDesc;
        HeapTuple resultTuple;
        Datum result;
        Datum result_values[2];
        bool result_is_null[2];
        double radius = 0;
 
        if (PG_ARGISNULL(0))
                PG_RETURN_NULL();
 
        geom = PG_GETARG_GSERIALIZED_P(0);
 
    /* Empty geometry?  Return POINT EMPTY with zero radius */
        if (gserialized_is_empty(geom))
        {
                lwcenter = (LWGEOM*) lwpoint_construct_empty(gserialized_get_srid(geom), LW_FALSE, LW_FALSE);
        }
        else
        {
                input = lwgeom_from_gserialized(geom);
                mbc = lwgeom_calculate_mbc(input);
 
                if (!(mbc && mbc->center))
                {
                        lwpgerror("Error calculating minimum bounding circle.");
                        lwgeom_free(input);
                        PG_RETURN_NULL();
                }
 
                lwcenter = (LWGEOM*) lwpoint_make2d(input->srid, mbc->center->x, mbc->center->y);
                radius = mbc->radius;
 
                lwboundingcircle_destroy(mbc);
                lwgeom_free(input);
        }
 
        center = geometry_serialize(lwcenter);
        lwgeom_free(lwcenter);
 
        get_call_result_type(fcinfo, NULL, &resultTupleDesc);
        BlessTupleDesc(resultTupleDesc);
 
        result_values[0] = PointerGetDatum(center);
        result_is_null[0] = false;
        result_values[1] = Float8GetDatum(radius);
        result_is_null[1] = false;
 
        resultTuple = heap_form_tuple(resultTupleDesc, result_values, result_is_null);
 
        result = HeapTupleGetDatum(resultTuple);
 
        PG_RETURN_DATUM(result);
}

References LWBOUNDINGCIRCLE::center, gserialized_get_srid(), gserialized_is_empty(), LW_FALSE, lwboundingcircle_destroy(), lwgeom_calculate_mbc(), lwgeom_free(), lwgeom_from_gserialized(), lwpoint_construct_empty(), lwpoint_make2d(), LWBOUNDINGCIRCLE::radius, result, LWGEOM::srid, POINT2D::x, and POINT2D::y.

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