Re: [hylafax-users] Hylafax miscalculating page counts on cover page

[olin.hylafax.7ia@xxxxxxxxxxxxxxxxx]

   From: Andrew Rinaldi <andrew.rinaldi@xxxxxxxxxxxx>
   Which HylaFAX version are you using ?

The standard ubuntu one
    version: 2:4.4.0-2
which I take to mean 4.4.0.

    From: Lee Howard <faxguy@xxxxxxxxxxxxxxxx>
    Here is the reason why...

    # grep %%Pages: paper.ps
    %%Pages: 15
    %%Pages: (atend)
    %%Pages: 1
    %%Pages: (atend)
    %%Pages: 1
    %%Pages: (atend)
    %%Pages: 1
    %%Pages: (atend)
    %%Pages: 1
    %%Pages: (atend)
    %%Pages: 1
    %%Pages: (atend)
    %%Pages: 1
    # grep %%Page: paper.ps
    %%Page: 1 1
    %%Page: 2 2
    %%Page: 3 3
    %%Page: 1 1
    %%Page: 1 1
    %%Page: 4 4
    %%Page: 5 5
    %%Page: 6 6
    %%Page: 7 7
    %%Page: 8 8
    %%Page: 9 9
    %%Page: 10 10
    %%Page: 11 11
    %%Page: 12 12
    %%Page: 1 1
    %%Page: 1 1
    %%Page: 13 13
    %%Page: 1 1
    %%Page: 1 1
    %%Page: 14 14
    %%Page: 15 15

Bingo. That looks like a smoking gun to me, too.

    So whether we sum up the %%Pages comments or count the instances of 
    %%Page comments... we come up with the same count: 21.  Obviously 
    something isn't right, though - either with the Postscript document or 
    with sendfax's page counting approach.  The document seems to "go back" 
    to page one 6 times in my read of things (but I'm no Postscript expert, 
    either).

    How is this Postscript document being created?

If you look at the actual document, you'll see it's a scientific research
paper, which, like just about all such, is created using latex and a dvi->ps
converter. The inserted %%Page: & %%Pages: comments are coming from the
embedded figures (page through the document; it'll jump out at you -- when you
get to a page where the page-comments get wonky, you'll suddenly notice that
page has figures on it). Those figures were rendered as independent PS files
by some other application, then included into the paper as a dvi special; the
dvi->ps converter then just blindly dropped the entire contents of the figure
files, page-count declarations & all, into the middle of the final PS
document. Voila.

I don't know enough about the rules for PostScript's structured-comments
to know if this is right or wrong. If latex is doing it, though, then I
am pretty sure there's a lot of it out there.

At the end of the day, PostScript is a Turing-complete language. The only real
way to know how many pages such a document comprises is to *execute it*, and
count the number of times it performs a showpage while the PS program is
running. Again, I wish I was enough of a ghostscript wizard to encapsulate
that task using gs, but I'm not.

One way to do it would be to execute ps2ps, which is basically just
    gs -q -sDEVICE=pswrite "-sOutputFile=$output-file" \
       -dNOPAUSE -dBATCH "$input-file"
to clean up the file -- this would produce a PS file that would contain
only two page-count lines:
    %%Pages: (atend)
    %%Pages: <the right number here>

I guess that for now I'll just avoid faxing PostScript files. If I may,
I'd like to suggest that people actively hacking on hylafax consider
shifting to a more robust page-counting technique for PostScript files
than hylafax is currently using.

Thanks for the help, Andrew, Lee.
    -Olin


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