private bool TryWriteEnvelope(object shape, out string result)
        {
            var a = _shapeConverter.CanConvert(ObjectType.Envelope);
            var b = _shapeConverter.GetObjectType(shape) == ObjectType.Envelope;

            if (_shapeConverter.CanConvert(ObjectType.Envelope) &&
                _shapeConverter.GetObjectType(shape) == ObjectType.Envelope)
            {
                var envelope = _shapeConverter.FromEnvelope(shape);
                result = string.Format(CultureInfo.InvariantCulture, "{0:F9} {1:F9} {2:F9} {3:F9}", envelope[0].X, envelope[0].Y, envelope[1].X, envelope[1].Y);
                return(true);
            }
            result = default(string);
            return(false);
        }