Добрый день, Aleksey1555.
Я очень советую ознакомиться с TWAIN Specification. Если кратко, то есть, к примеру, CAP_DUPLEX (Indicates whether the scanner supports duplex.), CAP_AUTOFEED (MSG_SET to TRUE to enable Source’s automatic feeding), CAP_FEEDERENABLED (If TRUE, Source’s feeder is available), и т.д..
По второй части:
DG_CONTROL / DAT_CAPABILITY operations for capability negotiation include:
Я очень советую ознакомиться с TWAIN Specification. Если кратко, то есть, к примеру, CAP_DUPLEX (Indicates whether the scanner supports duplex.), CAP_AUTOFEED (MSG_SET to TRUE to enable Source’s automatic feeding), CAP_FEEDERENABLED (If TRUE, Source’s feeder is available), и т.д..
По второй части:
DG_CONTROL / DAT_CAPABILITY operations for capability negotiation include:
- MSG_GET Returns the Current, Default and Available settings for a capability.
- MSG_GETCURRENT Returns the Current setting for a capability.
- MSG_GETDEFAULT Returns the value of the Source’s preferred Default values.
- MSG_RESET Returns the capability to its TWAIN Default (power-on) condition
(i.e. all previous negotiation is ignored). - MSG_RESETALL Returns all of the current values to the default settings used when the
driver was first installed. - MSG_SET Allows the application to set the Current value of a capability.
- MSG_SETCONSTRAINT Allows the application to set the Current and Default value(s) and
restrict the Available values to some subset of the Source’s power-on
set of values. Sources are strongly encouraged to allow the
application to set as many of its capabilities as possible, and further to
reflect these changes in the Source’s user interface. This will ensure
that the user can only select images with characteristics that are
useful to the consuming application.