DocView, mupdf and librsvg

DocView, mupdf and librsvg

[Manuel Giraud]

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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.

I think it would be wise to defaults `doc-view-mupdf-use-svg' to nil in
the upcoming Emacs 29.


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-- 
Manuel Giraud

Re: DocView, mupdf and librsvg

[Stephen Berman]

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.

Steve Berman

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?

Re: DocView, mupdf and librsvg

[Manuel Giraud]

Eli Zaretskii <eliz@gnu.org> writes:

[...]

> 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?

I could work on one but we might need a version number where this bug is
not here anymore, no?  Stephen did file this bug report to mupdf?
-- 
Manuel Giraud

Re: DocView, mupdf and librsvg

[Stephen Berman]

On Sat, 07 Jan 2023 16:03:01 +0100 Manuel Giraud <manuel@ledu-giraud.fr> wrote:

> Eli Zaretskii <eliz@gnu.org> writes:
>
> [...]
>
>> 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?
>
> I could work on one but we might need a version number where this bug is
> not here anymore, no?  Stephen did file this bug report to mupdf?

Sorry for the late reply.  It's a bit inconvenient to file a bug with
MuPDF (you have to register an account), and since Gregory Heytings
already sent a report with a patch for this issue to the Debian
bugtracker, I hope that will find its way upstream.

Steve Berman