@xiaoyuan wrote:
A driver implementation error or an error in my application?
Hard to know, as it is vendor’s related behavior …
A good data source will give you a log file and enough feedback to be able to find if it’s an application error or not.
Some vendors expose capabilities because it is mandatory from TWAIN spec, but that doesn’t mean that you can change their value.
CAP_AUTOSCAN for example is a scanner specific capability controlling the behavior of the feeder so it could be read only.