Hi, On 09.04.2008, at 21:27, stef wrote:
> Le Wednesday 09 April 2008 12:48:22 Ren? Rebe, vous avez ?crit : > >> >> As the backend controls the device and reads the image data somehow, >> it should have knowledge about the actual head position and should be >> able to perform the required actions even with the current interface. >> >> Where exactly should there be the problem? >> >> Yours, > > You are right that a backend can count how many times sane_cancel > has been > called after last sane_start() and that also by knowing if all data > planned > to be scan has been effectively read, it could sort things. But this a > workaround more prone to bugs than to have a function for regular > end of > scan, and another for error code path. It would also have to be > coded again > and again into backends needing it. > It is cheap to add, is about a one liner for frontends and help us > to write > better backends. For most backends, adding such a function would > simply > resolve in renaming sane_cancel to internal_cancel, and have it > called by > sane_cancel and the new function. Actively maintained backends will > be able > to take advantage of it. You are still just arguing around the dancing cow here. With a potentially new sane_end whatever function you still would have to keep track where the head is. A frontend may still read less data and in any case you would need to know where the head is to move it that specific way backwards in such a "CPU-less" "doing every step by the host" device. I can still do not see where another function call to signal a scan_end would help you. -- Ren? Rebe - ExactCODE GmbH - Europe, Germany, Berlin http://exactcode.de | http://t2-project.org | http://rene.rebe.name
