Re: DocView, mupdf and librsvg

[Eli Zaretskii]

> From: Stephen Berman <stephen.berman@gmx.net>
> Cc: "emacs-devel" <emacs-devel@gnu.org>
> Date: Sat, 07 Jan 2023 13:24:42 +0100
> 
> On Sat, 07 Jan 2023 13:07:22 +0100 Manuel Giraud <manuel@ledu-giraud.fr> 
> wrote:
> 
> > Hi,
> >
> > From some month now, to read PDF, DocView has switched from producing
> > PNG files for its page cache to producing SVG files.  I think it is a
> > good idea but I have found a bug (that is outside the scope of Emacs
> > that's why I'm reporting here): mutool could generate SVG files that
> > librsvg is not able to read back.
> >
> > FTR, I'm using mupdf 1.21.1 and librsvg 2.54.5.  I've attached a sample
> > PDF and the produced SVG if you want to test on your setting.
> 
> Yes, this is apparently a bug in how mutool processes "<" since at least
> version 1.21.0, see also bug#60308.
> 
> > I think it would be wise to defaults `doc-view-mupdf-use-svg' to nil in
> > the upcoming Emacs 29.

I think instead of changing the default unconditionally, we should
probe the version of mutool, and change it only for affected versions.
Would someone like to propose a patch along those lines?