linear_component_transfer_func (gint C, RsvgNodeComponentTransferFunc * user_data)
{
    return (user_data->slope * C) / 255 + user_data->intercept;
}
linear_component_transfer_func (gint C, RsvgNodeComponentTransferFunc * user_data)
{
    return (user_data->slope * C) / 255 + user_data->intercept;
}