bug#37880: 27.0.50; Changing font size in Info-mode messes up formatting

bug#37880: 27.0.50; Changing font size in Info-mode messes up formatting

[Stefan Kangas]

When I browse Info in "emacs -Q", the default formatting is fine when
I say C-h i and I see entries nicely lined up like so:

* IDLWAVE           Major mode and shell for IDL files.
* Newsticker        A feed reader for Emacs.

However, when I increase the font size using C-x C-+, I end up with
text that looks visually more like this:

* IDLWAVEMajor mode and shell for IDL files.
* NewstickerA feed reader for Emacs.

I see the same in menu entries in individual nodes.

I didn't look into it, but it would be nice if the formatting of menu
items could adjust as the font size increases.

Best regards,
Stefan Kangas

bug#37880: 27.0.50; Changing font size in Info-mode messes up formatting

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Wed, 23 Oct 2019 03:43:55 +0200
> 
> When I browse Info in "emacs -Q", the default formatting is fine when
> I say C-h i and I see entries nicely lined up like so:
> 
> * IDLWAVE           Major mode and shell for IDL files.
> * Newsticker        A feed reader for Emacs.
> 
> However, when I increase the font size using C-x C-+, I end up with
> text that looks visually more like this:
> 
> * IDLWAVEMajor mode and shell for IDL files.
> * NewstickerA feed reader for Emacs.

That's :align-to display property in action.  See bug#37858 for one
attempt to enhance it.

bug#37880: 27.0.50; Changing font size in Info-mode messes up formatting

[Lars Ingebrigtsen]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> So, I'd like to extend our `space` specifications so as to be able to
> specify a minimum width.  I came up with the patch below which lets you
> write:
>
>     (space :align-to FOO :min-width BAR)
>
> which seems to work fine, but while trying to update the Elisp doc for
> it I realized that maybe a better option is to extend the acceptable
> forms for FOO so it can be of the form:
>
>     (space :align-to (max FOO (+ BAR current-x)))

I think I'd actually prefer the first form -- it's easy to reason about,
and does what most usage cases want (i.e., align if possible, but if
not, then at least leave some space so that things don't run into each
other).

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#37880: 27.0.50; Changing font size in Info-mode messes up formatting

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Lars Ingebrigtsen [2022-05-07 14:07:24] wrote:
> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>> So, I'd like to extend our `space` specifications so as to be able to
>> specify a minimum width.  I came up with the patch below which lets you
>> write:
>>
>>     (space :align-to FOO :min-width BAR)
>>
>> which seems to work fine, but while trying to update the Elisp doc for
>> it I realized that maybe a better option is to extend the acceptable
>> forms for FOO so it can be of the form:
>>
>>     (space :align-to (max FOO (+ BAR current-x)))
>
> I think I'd actually prefer the first form -- it's easy to reason about,
> and does what most usage cases want (i.e., align if possible, but if
> not, then at least leave some space so that things don't run into each
> other).

The patch I came up with back then doesn't work right.  IIRC it's
because we need to change both the redisplay code and the
`current-column` code and it only changed one of the two.

IIRC, I decided then that the right fix is to rewrite the
`current-column` code to use the redisplay code (instead of trying to
mimic it), but I didn't get around to that (and IIRC it's not
completely straightforward because `current-column` currently behaves
differently *on purpose* in some cases (most importantly w.r.t treating
ellipsis-erased text) so fixing it right will imply changes in behavior
and figuring out how to do it without breaking existing uses).


        Stefan