Re: SANE frames

Oliver Rauch (oliver.rauch@Wolfsburg.DE)
Sat, 21 Aug 1999 14:35:00 +0200

David Mosberger-Tang wrote:

> >>>>> On Fri, 20 Aug 1999 15:48:49 +0200, Oliver Rauch <oliver.rauch@Wolfsburg.DE> said:
>
> Oliver> Another thing is that some scanners are able to do a "batch
> Oliver> scan", that means the scanner does scan multiple images
> Oliver> while the scanhead moves over the page, so the scanhead is
> Oliver> not moved into start position every time. But this can not
> Oliver> be used with the current sane standard.
>
> I disagree. sane_start() is a signal that the frontend is ready to
> read the next image. It does _not_ necessarily mean that the scanhead
> should go back to its start position.
>

Hi David,

I do not know how other scanners do batch scanning.
The umax scanners that support the batch scan mode need
the geometry for the current scan and the starting position for
the next scan when sane_start is called. But a frontend is not able
to set the geometry values for the next scanarea in the moment.

This could be done by a well known option that a backend makes
available when it supports the batch scanning mode, but:
to keep it compatible for all scanners we better could add a
possibilty to define multiple scanareas before the first
sane_start is called if we want to support the batch scan modes
of the scanners.

I don`t know if that is necessary but I think it is worth a discussion.

Bye
Oliver

--
EMAIL: Oliver.Rauch@Wolfsburg.DE
WWW: http://www.wolfsburg.de/~rauch

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