bug#58538: anti-alias fix results in ugly scaled fonts

bug#58538: anti-alias fix results in ugly scaled fonts

[Stephen Gildea]

At HEAD (29.0.50), I get an ugly scaled font for my sans-serif text.
I noticed it in MH-E, and you can reproduce it as follows:

    emacs -Q -fn fixed --eval "(buffer-face-set 'variable-pitch)"

Although the default font is specified on the command line as "fixed"
(from the misc-fixed X11 family of fonts), and the variable-pitch font
selected is not in the misc-fixed family, having "fixed" as the
default font affects the font selected for the "variable-pitch" face.
Which font it selects changed recently.

This bug seems to have been introduced by commit 6b1ed2f2c9,
"Fix antialias face attribute when text is scaled", 27 August.

In an Emacs built before that commit, the above command displays text
with a pretty sans-serif font.

That commit undoes some of the changes that addressed bug#17973.
Bug#17973 fixed display of misc-fixed fonts.  With that recent commit,
using misc-fixed fonts again breaks some faces.

bug#58538: anti-alias fix results in ugly scaled fonts

[Eli Zaretskii]

> From: Stephen Gildea <stepheng+emacs@gildea.com>
> Date: Fri, 14 Oct 2022 21:07:23 -0700
> 
> At HEAD, I get an ugly scaled font for my sans-serif text.
> I noticed it in MH-E, and you can reproduce it as follows:
> 
>     emacs -Q -fn fixed --eval "(buffer-face-set 'variable-pitch)"
> 
> Although the default font is specified on the command line as "fixed"
> (from the misc-fixed X11 family of fonts), and the variable-pitch font
> selected is not in the misc-fixed family, having "fixed" as the
> default font affects the font selected for the "variable-pitch" face.
> Which font it selects changed recently.
> 
> This bug seems to have been introduced by commit 6b1ed2f2c9,
> "Fix antialias face attribute when text is scaled", 27 August.
> 
> In an Emacs built before that commit, the above command displays text
> with a pretty sans-serif font.

The above works fine on my system: I get a "fixed" font without the
"--eval" argument, and variable-pitch font with it, as expected.

It sounds like so do you, but you don't like the variable-pitch font
you get, is that so?  If so, then the problem is with the fonts you
have installed, not necessarily with what Emacs produces.  That is,
assuming you do get variable-pitch font in the buffer, why are you
saying that Emacs doesn't perform correctly?  The font being "ugly" is
something only you know.

I'm guessing that what you see is due to some attributes of the
"fixed" font used as the default face's font.  The commit you
identified as the culprit preserves the attributes of the original
font which the face doesn't override, instead of throwing them away.
So I think the pretty sans-serif font you wanted to see is rejected
because it doesn't fit some of those attributes of the default face's
font.  Can you try figuring out which attribute(s) are those?  It
could be the :weight attribute, for example (the "medium" vs "regular"
issue, which is new in Emacs 29), or maybe :size.

> That commit undoes some of the changes that addressed bug#17973.
> Bug#17973 fixed display of misc-fixed fonts.  With that recent commit,
> using misc-fixed fonts again breaks some faces.

Please tell the details: which faces are broken and how?

bug#58538: anti-alias fix results in ugly scaled fonts

[Lars Ingebrigtsen]

[-- Attachment #1: Type: text/plain, Size: 724 bytes --]

Stephen Gildea <stepheng+emacs@gildea.com> writes:

> At HEAD (29.0.50), I get an ugly scaled font for my sans-serif text.
> I noticed it in MH-E, and you can reproduce it as follows:
>
>     emacs -Q -fn fixed --eval "(buffer-face-set 'variable-pitch)"
>
> Although the default font is specified on the command line as "fixed"
> (from the misc-fixed X11 family of fonts), and the variable-pitch font
> selected is not in the misc-fixed family, having "fixed" as the
> default font affects the font selected for the "variable-pitch" face.
> Which font it selects changed recently.

You didn't include the output from `M-x report-emacs-bug' -- what OS are
you running Emacs on?

On the current Ubuntu, your recipe gives me:


[-- Attachment #2: Type: image/png, Size: 36511 bytes --]

[-- Attachment #3: Type: text/plain, Size: 30 bytes --]


Without "-fn fixed", I get:


[-- Attachment #4: Type: image/png, Size: 99853 bytes --]

[-- Attachment #5: Type: text/plain, Size: 144 bytes --]


Which looks like the same font for `variable-pitch' to me, only a lot
larger (since this is a HiDPI screen and the "fixed" font is tiny here).

bug#58538: anti-alias fix results in ugly scaled fonts

[Mike Kupfer]

[-- Attachment #1: Type: text/plain, Size: 403 bytes --]

Hi Stephen, can you post screenshots of what you currently get and what
you expected?

I wonder if the difference has something to do with the font registry.

With 

  /usr/new/bin/emacs -Q -fn "-*-fixed-*-*-*-*-*-*-*-*-*-*-*-*" --eval "(buffer-face-set 'variable-pitch)"

or

  /usr/new/bin/emacs -Q -fn "-*-fixed-*-*-*-*-*-*-*-*-*-*-jisx0201.1976-*" --eval "(buffer-face-set 'variable-pitch)"

I get


[-- Attachment #2: default registry --]
[-- Type: image/png, Size: 13965 bytes --]

[-- Attachment #3: Type: text/plain, Size: 245 bytes --]


With

  /usr/new/bin/emacs -Q -fn "-*-fixed-*-*-*-*-*-*-*-*-*-*-iso10646-*" --eval "(buffer-face-set 'variable-pitch)"

or

  /usr/new/bin/emacs -Q -fn "-*-fixed-*-*-*-*-*-*-*-*-*-*-iso8859-*" --eval "(buffer-face-set 'variable-pitch)"

I get


[-- Attachment #4: iso10646 registry --]
[-- Type: image/png, Size: 16359 bytes --]

[-- Attachment #5: Type: text/plain, Size: 49 bytes --]


(This is on Debian Bullseye, running i3.)

mike

bug#58538: anti-alias fix results in ugly scaled fonts

[Stephen Gildea]

Version: 29.0.60

This bug was fixed 10 Dec 2022 by commit 30e3cb2135, "Unset the weight/slant/width in the spec when realizing a font".

bug#58538: anti-alias fix results in ugly scaled fonts

[Gregory Heytings]

>
> This bug was fixed 10 Dec 2022 by commit 30e3cb2135, "Unset the 
> weight/slant/width in the spec when realizing a font".
>

Would you mind sharing more details, and if possible a reproducer, about 
that bug?  What do you see and what would you expect to see, what do you 
mean by "ugly", which fonts do you use and how do you scale them, ...?

bug#58538: anti-alias fix results in ugly scaled fonts

[Gregory Heytings]

>
> This bug was fixed 10 Dec 2022 by commit 30e3cb2135, "Unset the 
> weight/slant/width in the spec when realizing a font".
>

Sorry, please ignore my previous post, I've misread yours.  You wrote that 
the bug is fixed, and closed it.  Somehow I thought you were opening a new 
bug.

bug#58538: anti-alias fix results in ugly scaled fonts

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

Mike Kupfer <mkupfer@alum.berkeley.edu> writes:

> Hi Stephen, can you post screenshots of what you currently get and what
> you expected?
>
> I wonder if the difference has something to do with the font registry.
>
> With 
>
>   /usr/new/bin/emacs -Q -fn "-*-fixed-*-*-*-*-*-*-*-*-*-*-*-*" --eval "(buffer-face-set 'variable-pitch)"
>
> or
>
>   /usr/new/bin/emacs -Q -fn "-*-fixed-*-*-*-*-*-*-*-*-*-*-jisx0201.1976-*" --eval "(buffer-face-set 'variable-pitch)"
>
> I get
>
>  
>
>
> With
>
>   /usr/new/bin/emacs -Q -fn "-*-fixed-*-*-*-*-*-*-*-*-*-*-iso10646-*" --eval "(buffer-face-set 'variable-pitch)"
>
> or
>
>   /usr/new/bin/emacs -Q -fn "-*-fixed-*-*-*-*-*-*-*-*-*-*-iso8859-*" --eval "(buffer-face-set 'variable-pitch)"
>
> I get
>
>  
>
>
> (This is on Debian Bullseye, running i3.)
>
> mike

Well yes, you will get a different font depending on what character set
you ask for.

The ``registry'' is technically the organization that has registered the
character set with the X Consortium, but that age is long over.  In
Emacs, it in effect means the character set.