bug#56823: 29.0.50; Inconsistent button size in NEWS

bug#56823: 29.0.50; Inconsistent button size in NEWS

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

Type C-h n RET to view NEWS, and then click on one of the buttons.
The big right arrow icon will be replaced by a smaller down arrow.

Both arrows are being displayed with the Symbola font.  It seems wrong
and unprofessional to place the size of our buttons at the mercy of the
user's symbol font.  I suggest making the default the XPM arrows used in
Custom instead.

In GNU Emacs 29.0.50 (build 88, x86_64-pc-linux-gnu)
 of 2022-07-29 built on trinity
Repository revision: 02b180e955ab0923b5fe2b8f362f1fedb092f760
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12014000
System Description: Fedora Linux 36 (Workstation Edition)

Configured using:
 'configure --with-x --with-x-toolkit=no --with-dumping=unexec
 --cache-file=/tmp/ccache --without-cairo'

Configured features:
ACL DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON LCMS2
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SECCOMP SOUND SQLITE3 THREADS TIFF UNEXEC WEBP X11 XDBE XFT XIM XINPUT2
XPM ZLIB

Important settings:
  value of $LANG: en_GB.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix

Major mode: NEWS

Minor modes in effect:
  outline-minor-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
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  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  button-mode: t

Load-path shadows:
None found.

Features:
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electric uniquify ediff-hook vc-hooks lisp-float-type elisp-mode mwheel
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Memory information:
((conses 16 133002 9879)
 (symbols 48 21529 0)
 (strings 32 32182 2042)
 (string-bytes 1 843394)
 (vectors 16 18989)
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 (intervals 56 1476 785)
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bug#56823: 29.0.50; Inconsistent button size in NEWS

[Eli Zaretskii]

> Date: Fri, 29 Jul 2022 20:59:57 +0800
> From:  Po Lu via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> 
> Type C-h n RET to view NEWS, and then click on one of the buttons.

When I do "C-h n" in the current master, I see no buttons at all.  Do
I need to do anything else to see the issue you are describing?

bug#56823: 29.0.50; Inconsistent button size in NEWS

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

Eli Zaretskii <eliz@gnu.org> writes:

>> Date: Fri, 29 Jul 2022 20:59:57 +0800
>> From:  Po Lu via "Bug reports for GNU Emacs,
>>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
>> 
>> 
>> Type C-h n RET to view NEWS, and then click on one of the buttons.
>
> When I do "C-h n" in the current master, I see no buttons at all.  Do
> I need to do anything else to see the issue you are describing?

Sorry, Lars seems to have just changed the behavior.  Try the buttons in
"C-h b" instead.

bug#56823: 29.0.50; Inconsistent button size in NEWS

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: 56823@debbugs.gnu.org
> Date: Fri, 29 Jul 2022 21:54:23 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> Date: Fri, 29 Jul 2022 20:59:57 +0800
> >> From:  Po Lu via "Bug reports for GNU Emacs,
> >>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> >> 
> >> 
> >> Type C-h n RET to view NEWS, and then click on one of the buttons.
> >
> > When I do "C-h n" in the current master, I see no buttons at all.  Do
> > I need to do anything else to see the issue you are describing?
> 
> Sorry, Lars seems to have just changed the behavior.  Try the buttons in
> "C-h b" instead.

OK.  So we should perhaps use :align-to display property to align the
text that follows the symbol.

bug#56823: 29.0.50; Inconsistent button size in NEWS

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

Eli Zaretskii <eliz@gnu.org> writes:

> OK.  So we should perhaps use :align-to display property to align the
> text that follows the symbol.

That still makes the individual buttons look wrong, since the first is
solid (in Symbola) while the second is hollow.

So I really think using an image by default is the better solution.

bug#56823: 29.0.50; Inconsistent button size in NEWS

[Lars Ingebrigtsen]

Po Lu <luangruo@yahoo.com> writes:

> Type C-h n RET to view NEWS, and then click on one of the buttons.
> The big right arrow icon will be replaced by a smaller down arrow.

Do you have a screenshot of the situation?

> Both arrows are being displayed with the Symbola font.

It sounds like our font selection code is wonky if it displays two
glyphs from the same font with different sizes.  What does `M-x
describe-char' on the two glyphs say?

bug#56823: 29.0.50; Inconsistent button size in NEWS

[Lars Ingebrigtsen]

In any case, I think I'm going to rework how the buttons are selected
slightly.  It should really check all the buttons in the same :group
whether they can be displayed, so that we don't end up with a symbol for
one button and text for a different button.  I.e., degrade for the
entire :group at once.

At the same time, I'm wondering whether it'd make sense to examine
whether we get the same font for all the items in the same :group,
because mixing fonts for this sort of this is seldom pretty.

It will have performance impacts, so perhaps some caching of the results
is also in order...

I'll get tinkering (but probably not this weekend).

bug#56823: 29.0.50; Inconsistent button size in NEWS

[Lars Ingebrigtsen]

But I see that the `symbol' entries in the buttons in outline-mode were
from different sections of the Unicode standard, so I've now chosen two
that are more related, which should help.

bug#56823: 29.0.50; Inconsistent button size in NEWS

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

[-- Attachment #1: Type: text/plain, Size: 159 bytes --]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Do you have a screenshot of the situation?

Sure.  Here's a screenshot of both kinds of buttons inside "C-h b".


[-- Attachment #2: Misshapen buttons --]
[-- Type: image/png, Size: 1610 bytes --]

[-- Attachment #3: Type: text/plain, Size: 146 bytes --]


They are being displayed with the same font, which just has differently
sized glyphs inside -- there is no problem with the font selection code.

bug#56823: 29.0.50; Inconsistent button size in NEWS

[Lars Ingebrigtsen]

Po Lu <luangruo@yahoo.com> writes:

> Sure.  Here's a screenshot of both kinds of buttons inside "C-h b".

Oh, the problem you're seeing isn't that the `symbol' items are
displayed with different sizes -- it's the faulty emoji detection (which
we're discussing how to fix over in the other bug report).

bug#56823: 29.0.50; Inconsistent button size in NEWS

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

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Po Lu <luangruo@yahoo.com> writes:
>
>> Sure.  Here's a screenshot of both kinds of buttons inside "C-h b".
>
> Oh, the problem you're seeing isn't that the `symbol' items are
> displayed with different sizes -- it's the faulty emoji detection

The Xft build doesn't support color Emoji (but I don't like them in the
first place, so I've deleted the color Emoji fonts from my system), so
they are being displayed by the same Symbola font.

bug#56823: 29.0.50; Inconsistent button size in NEWS

[Lars Ingebrigtsen]

Po Lu <luangruo@yahoo.com> writes:

> The Xft build doesn't support color Emoji (but I don't like them in the
> first place, so I've deleted the color Emoji fonts from my system), so
> they are being displayed by the same Symbola font.

Yes.  See bug#56691.

bug#56823: 29.0.50; Inconsistent button size in NEWS

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

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Po Lu <luangruo@yahoo.com> writes:
>
>> The Xft build doesn't support color Emoji (but I don't like them in the
>> first place, so I've deleted the color Emoji fonts from my system), so
>> they are being displayed by the same Symbola font.
>
> Yes.  See bug#56691.

Thanks, I tried to say something relevant there.  But IMHO the cause of
this problem is defaulting to the use of Emoji instead of proper images
as a substitute for buttons.

Not only does this cause problems if the user has an unexpected set of
fonts installed, compounded by how font rendering infrastructure has
never been designed for displaying buttons, it makes Emacs look very
unprofessionally made.  I cannot think of a single other GUI program
that uses Emoji to replace buttons.