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.

Regards,
    Stef

--
sane-devel mailing list: sane-devel@lists.alioth.debian.org
http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/sane-devel
Unsubscribe: Send mail with subject "unsubscribe your_password"
            to sane-devel-requ...@lists.alioth.debian.org

Reply via email to