[sane-devel] Well known option consensus

[m. allan noah]

On 1/22/07, abel deuring <adeuring at gmx.net> wrote:
> m. allan noah wrote:
>
> >> All this does not mean that the frontend cannot let the user select
> >> a smaller scan window within the page area -- but the clipping of
> >> the image must be done by the frontend.
> >>
> >
> > i agree completely other than the last sentence. it should be possible
> > for the backend
> > to let the user select overscan mode, and then adjust the scan
> > area/papersize as needed
> > to set tl-x/y 0,0 to the black area 16mm outside of the paper. i dont
> > think this violates the
> > spirit of the standard proposal, and it keeps overscan mode as similar
> > to the other modes
> > as possible. in fact, i think this is the right thing to do in sane1,
> > given recent user complaints on this mailing list.
>
> OK, misunderstanding cleared ;)
>
> Perhaps we're beginning to discuss a far too special feature -- but
> I would maintain nevertheless that it makes sense for a backend to
> simply disable tl-x, br-x, tl-y, br-y in overscan mode,

we agree to disagree :)

> and that to
> set the scan area automatically to a value that is somewhat larger
> than the page size.

i agree to set the max area to be larger than page size, yes.

> After all, this would allow the backend to fix
> the weird behaviour of the fi4210/5120 that the parameter page width
> must be set to a "wrong" value: real page width + 32mm in overscan
> mode, if one wants the dark background on the left side of the scan
> area.

i can fix that even without forcing the user to do full-page scans. i
just tack the 32mm
on when i build the command block if you are in overscan mode.

i need more docs and beta testers  to see if this page-width change is
needed with more expensive scanners.

this discusion has become too specialized, but it does point out the
concept that we were trying to capture in our 'pagesize' well-known
option suggestion:

the backend should endeavor to limit the scan area of an adf to values
which are sensible for the options being used, including, but not
limited to, paper size.

allan

-- 
"The truth is an offense, but not a sin"