Hi,
> > > When scanning the first page, half the data goes in this large buffer,
> > > then when the frontend asks for another page it comes out of the
> > > buffer very quickly.
[...]
> > That sounds reasonable. But can I be sure that front-ends will support
> > reading multiple pages one after the other with no call to ..._close()
[...]
> You can't be sure, but you can be quite sure that at least the graphical
> frontends won't call sane_close() between scans.
> On the whole, it's just an insufficiency in the current SANE Standard.
Let's do it as suggested then. I'll introduce a switch that's called
"duplex" and can be set to on or off; when "on", it will allocate a
chunk of memory upon starting the scan and deliver that at the next
request for image acquisition. - Would it make sense store the current
settings along with that buffer, and only deliver the second page if a
subsequent request is made *without changing* the settings (dpi,
window size etc.)?
I was thinking of maybe adding a third setting, "duplex=hack" or some
such, where the resulting image would be exactly twice as high (or
twice as wide) as requested, and it would contain the front and back
pages above each other (or next to each other).
That would not make a lot of sense with the graphical front-ends, but
somebody using "scanimage" could then use that option and easily
separate the images with pnmcut afterwards.
Would I run into trouble trying to return an image that is twice as
big as originally requested by the front-end?
Bye
Frederik
-- Frederik Ramm ## eMail frederik@remote.org ## N57°48.10' W005°40.32'-- Source code, list archive, and docs: http://www.mostang.com/sane/ To unsubscribe: echo unsubscribe sane-devel | mail majordomo@mostang.com
This archive was generated by hypermail 2b29 : Tue Feb 27 2001 - 11:55:10 PST