Am Samstag, den 26. September schrieb Stef:
> On 21/09/2015 21:04, M G Berberich wrote:
> >Hello,
> >
> >Am Mittwoch, den 16. September schrieb Stef:
> >>On 15/09/2015 15:57, M G Berberich wrote:
> >>>on a Canon LiDE 210, the 600 dpi Gray and Lineart scans are distorted
> >>>by a factor of 1.5 in y-direction (the scanner seems to scans with
> >>>600×900 dpi).
> >>>
> >>>Example:
> >>>The image at http://m-berberich.de/Diverses/genesys-600dpi-Gray.png
> >>>shows a 600 dpi Gray scan from a 5×5mm grid-paper, done with
> >>>
> >>> scanimage -l 20mm -t 20mm -x 45mm -y 45mm --resolution 600 --mode Gray
> >> it is a known bug, see
> >>https://alioth.debian.org/tracker/index.php?group_id=30186&atid=410366 .
> >The bug must have been introduced between 2013-07-02 (bd0f989) and
> >2013-07-17 (1c3ec28) probably in commit
> >
> > define specific LIDE210 sensor and motor instead of using LIDE110
> > ones
> >
> >from 2013-07-04 (730a2ba and 599f3ed).
> >
> >Anybody able to (re)fix this?
> >
> > MfG
> > bmg
> >
> Hello,
>
> previous code did gave the right number of lines. But those were of a
> higher resolution, giving improper aspect ratio. It cannot be fixed by
> reverted some changes.
>
> There are 3 options:
> - don't pretend the backend can do scan at these low resolution, and set
> 600 dpi as the lowest resolution in color, and 900 in gray, and let the user
> crop the picture.
> - do a 900x600 dpi scan (don't set yres = xres), which frontends rarely
> (if any) handle correctly
> - introduce yet another transformation stage in scan and do cropping
> into the backend.
>
> I personally consider the latter. However the "data pipeline" from raw
> data to sane compliant data has grown to the point it deserves some rewrite.
> This will take time.
I’m a bit puzzled. The old code (bd0f989 and befor) did
600dpi-gray/lineart-scans with correct aspect-ration. How did it do
it?
MfG
bmg
--
„Des is völlig wurscht, was heut beschlos- | M G Berberich
sen wird: I bin sowieso dagegn!“ | berbe...@fmi.uni-passau.de
(SPD-Stadtrat Kurt Schindler; Regensburg) | www.fmi.uni-passau.de/~berberic
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