bug#58041: [PATCH] docview: Use svg images when using mupdf for conversion

[Visuwesh <visuweshm@gmail.com>]

[புதன் ஜனவரி 04, 2023] Stefan Monnier wrote:

>> Attached patch makes mupdf produce svg images rather than png when svg
>> support is available.  This makes a noticeable improvement in image
>> quality when zooming in.
>
> IIUC this means that `+` and `-` now don't need to re-process the PDF, right?
> I think this is particularly valuable for things like ODT where `+/-`
> was pretty slow (because it re-created the PDF each time before having
> a chance to focus on the current page).

It depends on the value of `doc-view-scale-internally'.  The default
value (t) implies that we change the :width image property which leads
to blurry images when zooming.  In my case, even without zooming in, the
image quality was noticeably worse.
If `doc-view-scale-internally' is nil though, what you say happens.

> If that's the case it's probably worth mentioning in NEWS.
>
>> This also improves epub, odt, docx, etc. rendering since they also end
>> up using mupdf.  I'm not sure if this is NEWS worthy though.
>
> Other reasons it's worth mentioning in NEWS is because there's a new
> Custom to control it, and because it causes a regression for those LaTeX
> files which end up embedding bitmap fonts.  I just bumped into one and
> couldn't understand why every page took almost a minute to load;
> Removing `\usepackage[T1]{fontenc}` fixed the problem.

For the most part, I assumed MuPDF's svg and png conversion was
one-to-one.  My testing with small docx and Excel files went smooth so I
didn't think this feature warranted a NEWS entry.

>
>         Stefan

P.S. Sorry for the late reply, start of the semester had me busy.