Re: Putting auto-image-file-mode in Options menu

[David Kastrup <dak@gnu.org>]

Juri Linkov <juri@jurta.org> writes:

> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>>> There is already "Automatic File De/compression" menu item
>>> for auto-compression-mode in the Options menu, but no menu item
>>> for auto-image-file-mode.  This looks like an unintentional omission.
>>
>> I think it's omitted because it's a very rarely used feature.
>
> Indeed, auto-image-file-mode is useful only for viewing images.
> OTOH, editing image files as plain text in Emacs is a rare
> operation too.  And even with auto-image-file-mode set to t,
> editing is possible after visiting them with find-file-literally.
> With all this said, I have a question: is there any reason not
> to turn auto-image-file-mode on by default?

If you are working through a slow X connection, accidentally visiting
an image file could be a very expensive mistake.  In the past,
displaying an image that was overtall could really confuse Emacs.
This has become much better recently, but I don't know how the
situation is with overwide images.

Anyway, there are ASCII-based image file formats like ASCII PBM, PGM,
PPM, PAM and XBM and XPM.  Much more often than not, when I open such
files with Emacs, I really don't want to see the picture, but the
source text (to see comments, assignment of colors and palette, ranges
and so on).  And using find-file-literally (even if we provided it in
the menus, where it currently isn't) does not cater overly gracefully
for the line endings in those files.

> I would like to ask the same question for auto-compression-mode too.
> What is the reason not to turn it on by default?  How often people
> visit compressed files for editing without uncompressing?

I don't know how well auto-compression-mode deals with things like
missing compression commands.  If it fails gracefully, enabling it by
default should not do much harm.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum