class FilterFunction_offset extends FunctionExpressionImpl implements 
        GeometryTransformation {

    public ReferencedEnvelope invert(ReferencedEnvelope renderingEnvelope) {
        Double offsetX = getExpression(1).evaluate(null, Double.class);
        Double offsetY = getExpression(2).evaluate(null, Double.class);

        if (offsetX != null && offsetY != null) {
            ReferencedEnvelope offseted = new ReferencedEnvelope(renderingEnvelope);
            offseted.translate(-offsetX, -offsetY);
            return offseted;
        } else {
            return null;
        }
    }

    public  FilterFunction_offset();

}