[sane-devel] sane_cancel()

[Kåre Särs]

On Wednesdayen den 16 July 2008 09:28:49 Nicolas wrote:
> pixma backend can handle batch scan, I've tested it under both xsane and
> scanimage -b :
>
> $ scanimage -b
> Scanning -1 pages, incrementing by 1, numbering from 1
> Scanning page 1
> Scanned page 1. (scanner status = 5)
> Scanning page 2
> Scanned page 2. (scanner status = 5)
> Scanning page 3
> Scanned page 3. (scanner status = 5)
> Scanning page 4
> ...
>
> Is that correct ?
> AFAIK, there's no need to call sane_cancel () at the end of each page,
> when using the pixma backend.
>
> Kare, is there a way I can help with libksane and the pixma backend ?
> Could you describe exactly the test you're doing, and which fails ?
>
> Nicolas
>
Thankyou, the problem was that the backend did not accept writes to any 
parameters after a scan without a sane_cancel at the end. After a preview 
scan (without the sane_cancel) it was not possible to make a selection.

So the problem was that libksane doses/did not follow the standard. I'll fix 
libksane ASAP.

> >
> > sane_cancel should be called at the end of the batch, but not between
> > pages, otherwise backends which buffer the backside of a duplex read
> > will drop the image. this is an unfortunate historical accident,
> > because sane_cancel serving a dual purpose worked fine for flatbed
> > scanners that had no concept of a 'batch'.
> >

Thanks for the info.

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