bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Jim Meyering]

I was surprised to find that emacs now tries to display
all of coreutils' man/*.x files as images.  It seems to
treat any nonempty *.x file that way.

Instead of seeing what I normally treat as a simple text file with
man file [section]/text snippets, all I see is a small square (maybe
20x20 pixels) in the upper left corner of the window.

Reproduce via e.g.,

    echo foo > a.x && emacs -q a.x

The mode line reports that it is in (Image[imagemagick]) mode.

What version?

  $ emacs --version
  GNU Emacs 24.1.50.1

I build snapshots from bzr nearly daily, and could quickly bisect down to
this 3-day interval:

  GOOD emacs-2012-04-13.06h37/bin/emacs
  BAD emacs-2012-04-16.08h09/bin/emacs

When it works as I expected (i.e., I can see actual text in the primary
buffer, and no outlined square), I see "LD-script" in the mode line.

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Glenn Morris]

Jim Meyering wrote:

> I was surprised to find that emacs now tries to display
> all of coreutils' man/*.x files as images.  It seems to
> treat any nonempty *.x file that way.

Same issue as http://debbugs.gnu.org/11521

(memq 'X (imagemagick-types))  ->  (X X3F ...)

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Glenn Morris]

How about turning this ImageMagick thing around:

Instead of enabling image support for the 100s of extensions that
ImageMagick thinks are images, minus a few exceptions
(imagemagick-types-inhibit), have an explicit customizable list of the
types to accept, defaulting to things "everyone" agrees are really
images (bmp etc).

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Jim Meyering]

Glenn Morris wrote:
> How about turning this ImageMagick thing around:
>
> Instead of enabling image support for the 100s of extensions that
> ImageMagick thinks are images, minus a few exceptions
> (imagemagick-types-inhibit), have an explicit customizable list of the
> types to accept, defaulting to things "everyone" agrees are really
> images (bmp etc).

That sounds right to me.

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Stefan Monnier]

>> How about turning this ImageMagick thing around:
>> Instead of enabling image support for the 100s of extensions that
>> ImageMagick thinks are images, minus a few exceptions
>> (imagemagick-types-inhibit), have an explicit customizable list of the
>> types to accept, defaulting to things "everyone" agrees are really
>> images (bmp etc).
> That sounds right to me.

Sounds obvious enough, yes, please go ahead,


        Stefan

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Glenn Morris]

I've added an option imagemagick-type-enable with a conservative default.
I didn't put much thought into the default value.
I also wondered if for symmetry imagemagick-types-inhibit should maybe
be renamed to imagemagick-type-disable (or use -include and -exclude).

If anyone wants to change either of those it's fine by me.

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Jim Meyering]

Glenn Morris wrote:
> I've added an option imagemagick-type-enable with a conservative default.
> I didn't put much thought into the default value.
> I also wondered if for symmetry imagemagick-types-inhibit should maybe
> be renamed to imagemagick-type-disable (or use -include and -exclude).
>
> If anyone wants to change either of those it's fine by me.

Thanks!  This fixes it.

FYI, I've just noticed that bison/yacc grammar files were also affected.
I.e., editing any *.y file, the default mode would display only that
small useless square in the upper left corner.

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Stefan Monnier]

> I've added an option imagemagick-type-enable with a conservative default.
> I didn't put much thought into the default value.
> I also wondered if for symmetry imagemagick-types-inhibit should maybe
> be renamed to imagemagick-type-disable (or use -include and -exclude).

I don't think imagemagick-types-inhibit is important enough now to worry
about its name.  We could even mark is obsolete, couldn't we?


        Stefan

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Chong Yidong]

Stefan Monnier <monnier@IRO.UMontreal.CA> writes:

> I don't think imagemagick-types-inhibit is important enough now to worry
> about its name.  We could even mark is obsolete, couldn't we?

I don't think we should mark it as obsolete, since some users might want
to use a blacklist rather than a whitelist.  I changed its default to
nil, though, and added many more (hopefully uncontroversial) types to
the whitelist.

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Glenn Morris]

Chong Yidong wrote:

> I don't think we should mark it as obsolete, since some users might want
> to use a blacklist rather than a whitelist.  I changed its default to
> nil,

I don't see what the point of changing the inhibit default to nil was.
It makes it harder for someone to set imagemagick-enabled-types = t.

> , and added many more (hopefully uncontroversial) types to the
> whitelist.

CIN is controversial: http://debbugs.gnu.org/11521

Why are EPS/EPDF files treated differently to PS/PDF files?

bug#11557: cannot view nonempty *.x file using emacs (Image[imagemagick])

[Chong Yidong]

Glenn Morris <rgm@gnu.org> writes:

> I don't see what the point of changing the inhibit default to nil was.
> It makes it harder for someone to set imagemagick-enabled-types = t.

I guess you're right.  Switched back.

> CIN is controversial: http://debbugs.gnu.org/11521

OK, removed.

> Why are EPS/EPDF files treated differently to PS/PDF files?

My original thought was that the "encapsulated" versions tend to be
figures rather than documents.  But on second thought, since EPS
etc. are displayed just fine by DocView, there is no need to have those
there.  Removed.