[UFO Chicago] The Two-Stage Solution

[Carl Karsten]

What is the upper problem you are trying to solve?

Where are you getting PDFs from, and why do you want gif?

On Wed, Nov 15, 2023 at 12:06 PM Jay F. Shachter <jay at m5.chicago.il.us> wrote:
>
>
> The problem, you will recall, is that the recent versions of
> ghostscript no longer convert from PostScript or PDF to GIF.
> Ghostscript use to do it, but recent versions are unwilling to.
>
> The "convert" program, from the Imagemagick suite, is willing to
> convert from PostScript to GIF, but it doesn't know how to.
> That is to say, it tries, but it does a really bad job.
>
> A two-stage solution has been proposed: use ghostscript to convert
> from PostScript or PDF to some other image format, like, e.g.,
> pnm:
>
>  gs -r600 -dNOPAUSE -q -sDEVICE=png16m -dBATCH -dAutoRotatePages=/None -sOutputFile=file.png file.ps
>
> and then use ImageMagick to convert from that other image format to gif:
>
>  convert file.png file.gif
>
> and then don't forget to remove the intermediary file:
>
>  rm file.png
>
> This works.  I have, until now, been employing a different solution,
> which is faster, but it required a large initial investment of time.
>  From the source code of the last version of gs that supported GIF
> conversion (I think that was version 5, or thereabouts), I took the
> GIF conversion functions, and I added them to the source code of the
> subsequent versions of gs, and then rebuilt gs.  This gave me a
> version of gs with all the functionality of the current version, plus
> it did GIF conversion.  This worked until version 9.  Version 9
> changed the interface to the conversion functions, and I was unwilling
> to spend the time necessary to rewrite the GIF conversion functions to
> support the new interface.  So I now have GhostScript version 9, which
> I use for all things except for generating GIF output, and I have, in
> a different directory, GhostScript version 8, which I now use solely
> for generating GIF output.  I use, not the two-stage solution, but the
> two-ghostscripts solutions.
>
> Both of these solutions, though, are bogus.  Why was the GIF
> conversion functionality taken out of GhostScript version 5?  Because
> someone found out that it was patented?  Even if that was true, surely
> the patent has expired by now.  Patents are short-lived.  GhostScript
> should support GIF conversion.  My original question remains: Why
> doesn't it?
>
>         Jay F. Shachter
>         6424 North Whipple Street
>         Chicago IL  60645-4111
>                 (1-773)7613784   landline
>                 (1-410)9964737   GoogleVoice
>                 http://m5.chicago.il.us
>                 jay at m5.chicago.il.us
>
>         "But when she traced the killer's IP address ... it was in the 192.168/16 block!"
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-- 
Carl K