bug#21640: 25.0.50; Fontset-font is never scaled

bug#21640: 25.0.50; Fontset-font is never scaled

[Artur Malabarba]

I have the following snippet in my init file.

(set-face-attribute 'default nil :height 100
                    :font "SourceCodePro Medium")
(set-fontset-font "fontset-default" nil
                  (font-spec :size 40 :name "Symbola"))

On my Ubuntu system, this means any characters no supported by the
main font (SourceCodePro) will displayed in the Symbola font and
considerably scaled up in size (good).

On my Arch GNU/Linux system, the same happens, except the Symbola
characters are not scaled up in size. By inspecting them with C-u C-x
= I can verify that the Symbola font is indeed being used:

   xft:-unknown-Symbola-normal-normal-semicondensed-*-13-*-*-*-*-0-iso10646-1
(#x1BE3)

Both are compiled from master.

bug#21640: 25.0.50; Fontset-font is never scaled

[Eli Zaretskii]

> Date: Wed, 7 Oct 2015 11:52:04 +0100
> From: Artur Malabarba <arturmalabarba@gmail.com>
> 
> I have the following snippet in my init file.
> 
> (set-face-attribute 'default nil :height 100
>                     :font "SourceCodePro Medium")
> (set-fontset-font "fontset-default" nil
>                   (font-spec :size 40 :name "Symbola"))
> 
> On my Ubuntu system, this means any characters no supported by the
> main font (SourceCodePro) will displayed in the Symbola font and
> considerably scaled up in size (good).
> 
> On my Arch GNU/Linux system, the same happens, except the Symbola
> characters are not scaled up in size. By inspecting them with C-u C-x
> = I can verify that the Symbola font is indeed being used:
> 
>    xft:-unknown-Symbola-normal-normal-semicondensed-*-13-*-*-*-*-0-iso10646-1
> (#x1BE3)
> 
> Both are compiled from master.

Is the configuration the same, including the font back-ends?

In general, I think you are getting undefined behavior: you specify a
fixed size of 40 pixels, but expect it to be a kind of "relative"
size?  Is that documented somewhere?

(I never used explicit size parameters in fontsets, so maybe I'm
missing something.)

bug#21640: 25.0.50; Fontset-font is never scaled

[Artur Malabarba]

> Is the configuration the same, including the font back-ends?

The init files are the same (and I see this problem from emacs -Q
too), but there are many differences in system configuration outside
Emacs (most of which I probably don't know).

I haven't configured font-backends. If I query for it in
frame-parameters I get `(font-backend xft x)'.
Swapping their order or removing the `x' makes no difference. Removing
the `xft' segfaults Emacs.

> In general, I think you are getting undefined behavior: you specify a
> fixed size of 40 pixels, but expect it to be a kind of "relative"
> size?  Is that documented somewhere?

No, I expect to be bigger than my regular font, which is much less
than 40 pixels. I can change it to any other number with no effect.
I tried using a float too, which should represent a size in points
according to the docstring, but there's still no difference.

bug#21640: 25.0.50; Fontset-font is never scaled

[Eli Zaretskii]

> Date: Wed, 7 Oct 2015 20:14:43 +0100
> From: Artur Malabarba <arturmalabarba@gmail.com>
> Cc: 21640@debbugs.gnu.org
> 
> > Is the configuration the same, including the font back-ends?
> 
> The init files are the same (and I see this problem from emacs -Q
> too), but there are many differences in system configuration outside
> Emacs (most of which I probably don't know).
> 
> I haven't configured font-backends. If I query for it in
> frame-parameters I get `(font-backend xft x)'.
> Swapping their order or removing the `x' makes no difference. Removing
> the `xft' segfaults Emacs.
> 
> > In general, I think you are getting undefined behavior: you specify a
> > fixed size of 40 pixels, but expect it to be a kind of "relative"
> > size?  Is that documented somewhere?
> 
> No, I expect to be bigger than my regular font, which is much less
> than 40 pixels. I can change it to any other number with no effect.
> I tried using a float too, which should represent a size in points
> according to the docstring, but there's still no difference.

Could it be that the version of Symbola is different between the two
systems, and one of them cannot be scaled like you want?

bug#21640: 25.0.50; Fontset-font is never scaled

[Artur Malabarba]

2015-10-07 20:20 GMT+01:00 Eli Zaretskii <eliz@gnu.org>:
> Could it be that the version of Symbola is different between the two
> systems, and one of them cannot be scaled like you want?

It's possible, I don't know how to look up font versions. The version
of the package that I installed for this font is 8.0.0 on Arch, but I
can't even find out where the font comes from on Ubuntu (probably
pre-installed).

Anyway, the matter is more complicated then I initially thought. Even
on Ubuntu it doesn't work on every Symbola character.
For instance, I can get it to work with the "MATHEMATICAL
DOUBLE-STRUCK DIGIT ____" family. If I inspect the char I get this
description:
    xft:-unknown-Symbola-normal-normal-semicondensed-*-50-*-*-*-*-0-iso10646-1
(#x14CD)

But it doesn't seem to work with anything from the "SMILING FACE WITH
___" family.
    xft:-unknown-Symbola-normal-normal-semicondensed-*-16-*-*-*-*-0-iso10646-1
(#x18FA)

Note how one is correctly using the size 50 (which I had previously
set via `(font-spec :size 50 :name "Symbola")'), and the other is
using size 16.
Does anyone know where is the code responsible for figuring out this
number when the char is inserted? (so I can investigate)

Anyway, I'm pretty sure most characters worked on a previous Arch
installation I had. I'll test it on a previous Emacs version to figure
out if the regression is in Emacs or in my system.

bug#21640: 25.0.50; Fontset-font is never scaled

[Lars Ingebrigtsen]

Artur Malabarba <arturmalabarba@gmail.com> writes:

> Anyway, the matter is more complicated then I initially thought. Even
> on Ubuntu it doesn't work on every Symbola character.
> For instance, I can get it to work with the "MATHEMATICAL
> DOUBLE-STRUCK DIGIT ____" family. If I inspect the char I get this
> description:
>     xft:-unknown-Symbola-normal-normal-semicondensed-*-50-*-*-*-*-0-iso10646-1
> (#x14CD)
>
> But it doesn't seem to work with anything from the "SMILING FACE WITH
> ___" family.
>     xft:-unknown-Symbola-normal-normal-semicondensed-*-16-*-*-*-*-0-iso10646-1
> (#x18FA)

I tried reproducing this (starting from -Q), but I'm not sure whether
I'm doing it right.  First I evaled:

(set-fontset-font "fontset-default" nil
                  (font-spec :size 80 :name "Unifont Upper"))


Then inserted SMILING FACE WITH SMILING EYES AND THREE HEARTS (which
uses that font), and I got:

    ftcrhb:-PfEd-Unifont Upper-normal-normal-normal-*-80-*-*-*-d-0-iso10646-1 (#x2886)

Character code properties: customize what to show
  name: SMILING FACE WITH SMILING EYES AND THREE HEARTS

So it seems to work for me.  Has this bug gone away in the meanwhile, or
are you still seeing it?

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

bug#21640: 25.0.50; Fontset-font is never scaled

[Stefan Kangas]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Artur Malabarba <arturmalabarba@gmail.com> writes:
>
>> Anyway, the matter is more complicated then I initially thought. Even
>> on Ubuntu it doesn't work on every Symbola character.
>> For instance, I can get it to work with the "MATHEMATICAL
>> DOUBLE-STRUCK DIGIT ____" family. If I inspect the char I get this
>> description:
>>     xft:-unknown-Symbola-normal-normal-semicondensed-*-50-*-*-*-*-0-iso10646-1
>> (#x14CD)
>>
>> But it doesn't seem to work with anything from the "SMILING FACE WITH
>> ___" family.
>>     xft:-unknown-Symbola-normal-normal-semicondensed-*-16-*-*-*-*-0-iso10646-1
>> (#x18FA)
>
> I tried reproducing this (starting from -Q), but I'm not sure whether
> I'm doing it right.  First I evaled:
>
> (set-fontset-font "fontset-default" nil
>                   (font-spec :size 80 :name "Unifont Upper"))
>
>
> Then inserted SMILING FACE WITH SMILING EYES AND THREE HEARTS (which
> uses that font), and I got:
>
>     ftcrhb:-PfEd-Unifont Upper-normal-normal-normal-*-80-*-*-*-d-0-iso10646-1 (#x2886)
>
> Character code properties: customize what to show
>   name: SMILING FACE WITH SMILING EYES AND THREE HEARTS
>
> So it seems to work for me.  Has this bug gone away in the meanwhile, or
> are you still seeing it?

More information was requested, but none was given within 21 weeks, so
I'm closing this bug.  If this is still an issue, please reply to this
email (use "Reply to all" in your email client) and we can reopen the
bug report.

Best regards,
Stefan Kangas