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Forums › TWAIN Classic › Document Feeder Control
I was wondering if anyone has successfully used the CAP_FEEDPAGE, CAP_CLEARPAGE and CAP_REWINDPAGE capabilities.
I finally have a scanner to play with that claims to support these, but there seems to be very little information on how they are meant to be used.
I’m able to set these extended capabilities, enable the device and use MSG_SET on them, but nothing seems to happen. If anyone has information or example code, please let me know.
Unlike most other caps, these caps are expected to directly control the feeder actions. E.g., for CAP_CLEARPAGE, the MSG_SET must be immediately mapped to a call in your scanner driver interface that ejects the current page.
The effectiveness of these caps depend a lot upon the scanner hardware/firmware design. Thus if a scanner is using internal memory buffers for ‘scanning ahead’, CAP_CLEARPAGE and CAP_FEEDPAGE become virtually useless.