[sane-devel] maximum image size for a scan for Canon pixma backend

[Nicolas Martin]

Le vendredi 31 décembre 2010 à 02:55 +0900, Gernot Hassenpflug a écrit :
> On Fri, Dec 31, 2010 at 2:50 AM, Robert Krawitz <rlk at alum.mit.edu> wrote:
> > On Fri, 31 Dec 2010 02:41:10 +0900, Gernot Hassenpflug wrote:
> >> On Fri, Dec 31, 2010 at 2:19 AM, Gerard Klaver <gerard.klaver at xs4all.nl> wrote:
> >>> On Fri, 2010-12-31 at 01:29 +0900, Gernot Hassenpflug wrote:
> >>>> Dear all,
> >>>> I have been involved in trying to support the Canoscan 9000F, and the
> >>>> testing community has grown to about 15 individuals. A few of them
> >>>> have programming knowledge and tonight one individual send in
> >>>> corrected code to handle the final hurdle: correctly aligning the
> >>>> sub-images in the 9600dpi TPU mode. So the scanner is now supported
> >>>> for all modes.
> >>>>
> >>>> However, for large images at both 4800dpi and 9600dpi modes, it seems
> >>>> the max size of the image is limited in some way, so that only a
> >>>> section of the desired image is delivered. Is this something that can
> >>>> be set in the individual driver files (like pixma_mp150.c) or in some
> >>>> of the generic pixma driver .c or .h files (which I do not want to
> >>>> touch if possible)? I don't see a problem in the linesize or
> >>>> dimensions, only in the image_size value seen by [pixma] debugging
> >>>> output.
> >>>>
> >>>> Best regards,
> >>>> Gernot Hassenpflug
> >>>>
> >>>> --
> >>>> sane-devel mailing list: sane-devel at lists.alioth.debian.org
> >>>> http://lists.alioth.debian.org/mailman/listinfo/sane-devel
> >>>> Unsubscribe: Send mail with subject "unsubscribe your_password"
> >>>>              to sane-devel-request at lists.alioth.debian.org
> >>>
> >>> One possible solution (if not yet done), is to check the declaration of
> >>> the  image_size parameter, for a 9600 dpi A4 scan (color) size is about
> >>> 550 000 000 000 bytes. (long long is needed)
> >>
> >> Hi, thank you for that. I see that image_size is currently declared as
> >> "unsigned". I imagine that changing the declaration will need to be
> >> checked in all places where the calculations using image_size are
> >> done, or not?
> >>
> >> Currently, from the report I obtain from a test user, a 4800x4800dpi image with
> >>
> >> dimensions: 32824 px (width) * 47248 px (height)
> >>
> >> should have a image_size of 4652605056 bytes (W*H*3 for channel number)
> >>
> >> whereas the actual image_size used is 357637760 bytes (approximately
> >> 341.1 MiB). I am still trying to ascertain whether for some reason the
> >> wrong calculation for image_size might have been made, but certainly
> >> the width and height are correctly there.
> >
> > 32824 * 47248 * 3 - 357637760 = 4294967296
> >
> > which is exactly 2^32.  So that suggests exactly the problem described
> > above.
> 
> Ah! I suspected it was that, but forgot I had to take the difference
> to get this number. Fantastic! Well, that sounds like somewhat of a
> issue then for the SANE Canon maintainer to comment on. I guess this
> issue had to come up eventually.

Should be possible to extend the image size in pixma backend by
declaring uint64_t instead of unsigned the following variables:

image_byte_read (in pixma.c), 
image_size (in pixma.h)
cur_image_size (in pixma_common.h)

Debug statements should also to be adjusted, %llu instead of %u in the
different format strings, although this gives a compilation warning
anyway, as the gcc compile statement uses the -pedantic flag. 

Unless someone has a better solution for sprintf 64 bits integers ?

Anyway, could you give a try on 9000F with those changes ?

Nicolas