[sane-devel] Issue 642

[Andy Bennett]

Hi,

Thanks for getting back to me and for including the details that you were 
able to discover.

I'm glad you found a solution in the end.

Good luck with the scanning.


> thank you very much for your help! I was indeed able to analyze 
> a little bit 
> more -- see my comment below. However, since my scanner seems to work 
> flawlessly with the airscan backend with even more options than the hpaio 
> backend supports, I will not invest more time into this 
> analyzes. Nevertheless 
> I would like to share what I found out thus far.
>
> On Sonntag, 18. Juni 2023 14:14:42 CEST Andy Bennett wrote:
>> I've just read the issue for the first time and haven't been 
>> involved but I
>> noticed that you mentioned "Works with all formats (jpeg, tiff, png, pnm)
>> and with a resolution of 600. scanimage does not crash, the images are not
>> corrupt." and then provide examples where it does crash.
>> 
>> However, you don't say if you can make it crash with a pnm 
>> format output. ...
>
> The result of my analysis points to problem number (2): the 
> hpaio backend is 
> not sending enough data. I guess, this should already have been 
> clear to Ralph 
> from the beginning.
>
> With pnm format scanimage scans all pages and works without 
> noticeable error. 
> However, when scanning from the ADF, all pages are missing some data. The 
> length of the images corresponds to the data the hpaio backend transferred, 
> according to the debug trace. Since some data are missing, the images are 
> syntactically not correct and various tools, like identify, complain.
>
> What made me wonder was, that skanlite produces syntactically 
> correct images, 
> in contrast to scanimage. The debug trace shows, that the hpaio backend 
> transfers the same amount of data in both cases, when scanning 
> with scanimage 
> and skanlite. If the debug trace is not lying and I am 
> understanding what it 
> says, I must conclude, that somehow skanlite is adding some 
> data at the end of 
> the image, just so much as are missing, so that the image is syntactically 
> correct. To analyze this further would have been my next step. Fortunately, 
> airscan came to my rescue and makes any further analyzes obsolete.
>
> P.S. In the meantime I updated to openSUSE 15.5 which uses a 
> newer version of 
> hplip and in particular hpaio, but it still does not work any better.
>
> Best regards
> Karl
>
>
>
>

-- 
Best wishes,
@ndy

-- 
andyjpb at ashurst.eu.org
http://www.ashurst.eu.org/
0x7EBA75FF