Recent changes incorrectly calculate font size within daemon mode

Recent changes incorrectly calculate font size within daemon mode

[Yuri D'Elia]

I've updated my current emacs build to discover a new quirk:

- if I start emacs normally, all is good
- if I start it through emacsclient -c, the screen DPI is not correctly
  calculated. It looks like my fontconfig/Xres DPI settings are ignored.

This change must have been introduced in one of the commits in master in
the last week at most, however I don't see anything pointing to
fontconfig/daemon mode changes.

Before I dig into it, any possible explanation?

Re: Recent changes incorrectly calculate font size within daemon mode

[Yuri D'Elia]

On Wed, Aug 29 2018, Yuri D'Elia wrote:
> - if I start emacs normally, all is good
> - if I start it through emacsclient -c, the screen DPI is not correctly
>   calculated. It looks like my fontconfig/Xres DPI settings are ignored.
>
> This change must have been introduced in one of the commits in master in
> the last week at most, however I don't see anything pointing to
> fontconfig/daemon mode changes.

I bisected this down until this commit which introduced the regression:
d77d01d22902acdc45c2c7059de4f1b158ab5806 (bignum stuff), which does
mention a few changes to frame parameters.

Maybe those changes are not handles when a frame is created from a
daemon instance?

Re: Recent changes incorrectly calculate font size within daemon mode

[Paul Eggert]

Yuri D'Elia wrote:
> The following message is a courtesy copy of an article
> that has been posted to gmane.emacs.devel as well.
> 
> On Wed, Aug 29 2018, Yuri D'Elia wrote:
>> - if I start emacs normally, all is good
>> - if I start it through emacsclient -c, the screen DPI is not correctly
>>    calculated. It looks like my fontconfig/Xres DPI settings are ignored.
>>
>> This change must have been introduced in one of the commits in master in
>> the last week at most, however I don't see anything pointing to
>> fontconfig/daemon mode changes.
> 
> I bisected this down until this commit which introduced the regression:
> d77d01d22902acdc45c2c7059de4f1b158ab5806 (bignum stuff), which does
> mention a few changes to frame parameters.
> 
> Maybe those changes are not handles when a frame is created from a
> daemon instance?

Quite possibly, yes. What platform are you running on? And can you tell me 
exactly how you set fontconfig/Xres? I am having trouble reproducing the problem.

Re: Recent changes incorrectly calculate font size within daemon mode

[Yuri D'Elia]

On Thu, Aug 30 2018, Paul Eggert wrote:
> Quite possibly, yes. What platform are you running on? And can you tell
> me exactly how you set fontconfig/Xres? I am having trouble reproducing
> the problem.

This is on debian unstable, X11 lucid build (--without-gsettings
--with-x-toolkit=lucid).

After looking at my config, I think the only part that matters is this:

$ xrdb -q | grep dpi
Xft.dpi:        95

DPI values are also set explicitly via xrandr --output [all outputs]
--dpi 95 to be consistent, but AFAIK emacs always ignored xrandr values.

Other settings are correctly applied, so it's the font scaling which has
some issues when emacs is started via --daemon (both
--fg-daemon/--bg-daemon result in the same behavior).

Re: Recent changes incorrectly calculate font size within daemon mode

[Paul Eggert]

Yuri D'Elia wrote:
> On Thu, Aug 30 2018, Paul Eggert wrote:
>> Quite possibly, yes. What platform are you running on? And can you tell
>> me exactly how you set fontconfig/Xres? I am having trouble reproducing
>> the problem.
> 
> This is on debian unstable, X11 lucid build (--without-gsettings
> --with-x-toolkit=lucid).
> 
> After looking at my config, I think the only part that matters is this:
> 
> $ xrdb -q | grep dpi
> Xft.dpi:        95
> 
> DPI values are also set explicitly via xrandr --output [all outputs]
> --dpi 95 to be consistent, but AFAIK emacs always ignored xrandr values.
> 
> Other settings are correctly applied, so it's the font scaling which has
> some issues when emacs is started via --daemon (both
> --fg-daemon/--bg-daemon result in the same behavior).
> 

I'm not seeing the problem on my Ubuntu 18.04 desktop. I configured Emacs master 
this way:

./configure --enable-gcc-warnings --without-gsettings --with-x-toolkit=lucid

And I ran it this way:

src/emacs -Q --fg-daemon
lib-src/emacsclient -c

I also tried --fg-daemon and couldn't reproduce it that way either.

What is your native screen resolution and how are you setting your font scaling 
factor? I used gnome-tweaks to set my font scaling factor to 1.30. My xrdb 
output says:

$ xrdb -q | grep dpi
Xft.dpi:	124.7998046875

My native screen resolution is 1920x1200 and my native Xft.dpi is 96.

Re: Recent changes incorrectly calculate font size within daemon mode

[Yuri D'Elia]

On Thu, Aug 30 2018, Paul Eggert wrote:
> What is your native screen resolution and how are you setting your font
> scaling factor? I used gnome-tweaks to set my font scaling factor to
> 1.30. My xrdb output says:

I have no clue what gnome-tweaks does in detail, so cannot say anything
specific about it, but I went on debugging further on the init side.

I noticed I also call 'set-face-attribute during init.el:

  (set-face-attribute 'default :nil "DejaVu Sans" :height 150)

By doing an eval after creating the first frame, the font size is
correctly calculated. So it seems that something isn't set early enough
compared to before.

Re: Recent changes incorrectly calculate font size within daemon mode

[Michael Heerdegen]

Yuri D'Elia <wavexx@thregr.org> writes:

> I've updated my current emacs build to discover a new quirk:
>
> - if I start emacs normally, all is good
> - if I start it through emacsclient -c, the screen DPI is not correctly
>   calculated. It looks like my fontconfig/Xres DPI settings are ignored.

Maybe something related: when I use `enlarge-font' from "frame-cmds.el",
I get the error

| Debugger entered--Lisp error: (wrong-type-argument stringp nil)
|   string-to-number(nil)
|   (+ (string-to-number (aref xlfd-fields xlfd-regexp-pixelsize-subnum)) increment)
|   (let ((new-size (+ (string-to-number (aref xlfd-fields xlfd-regexp-pixelsize-subnum)) increment))) (if (> new-size 0) nil (signal 'font-too-small (list new-size))) (aset xlfd-fields xlfd-regexp-pixelsize-subnum (number-to-string new-size)))
|   (let ((xlfd-fields (x-decompose-font-name fontname))) (if xlfd-fields nil (error "Cannot decompose font name")) (let ((new-size (+ (string-to-number (aref xlfd-fields xlfd-regexp-pixelsize-subnum)) increment))) (if (> new-size 0) nil (signal 'font-too-small (list new-size))) (aset xlfd-fields xlfd-regexp-pixelsize-subnum (number-to-string new-size))) (aset xlfd-fields xlfd-regexp-pointsize-subnum "*") (aset xlfd-fields xlfd-regexp-avgwidth-subnum "*") (x-compose-font-name xlfd-fields))
|   frcmds-enlarged-font-name("-PfEd-DejaVu Sans Mono-normal-normal-normal-*-*-*-..." #<frame *scratch*      micha@drachen 0x8eb3510> 1)
|   (setq fontname (frcmds-enlarged-font-name fontname frame increment))
|   (let ((fontname (cdr (assq 'font (frame-parameters frame)))) (count enlarge-font-tries)) (setq fontname (frcmds-enlarged-font-name fontname frame increment)) (while (and (not (x-list-fonts fontname)) (wholenump (setq count (1- count)))) (setq fontname (frcmds-enlarged-font-name fontname frame increment))) (if (x-list-fonts fontname) nil (error "Cannot change font size")) (modify-frame-parameters frame (list (cons 'font fontname))) (if (< emacs-major-version 21) (progn (frame-update-faces frame))))
|   enlarge-font(1)

The problem is that (aref xlfd-fields xlfd-regexp-pixelsize-subnum)
returns nil which I guess is not correct.

Resetting to d77d01d22902acdc45c2c7059de4f1b158ab5806 as mentioned in
Yuri's other messages fixes this problem.  I'm not starting Emacs
through emacsclient, though.


HTH,

Michael.

Re: Recent changes incorrectly calculate font size within daemon mode

[Paul Eggert]

Michael Heerdegen wrote:
> The problem is that (aref xlfd-fields xlfd-regexp-pixelsize-subnum)
> returns nil which I guess is not correct.

Thanks for this example. However, it relies on some stuff from Drew Adams that 
is not part of Emacs. Can you please give a self-contained example of how to 
reproduce the problem? (If the first step is "download foo from bar", that's 
fine; however, I couldn't easily figure out how to download Adams's code from 
his wiki, as a page seems to be missing.)

Also, what platform are you running on, and have you configured your fonts in 
any way?

Thanks.

Re: Recent changes incorrectly calculate font size within daemon mode

[Michael Heerdegen]

Paul Eggert <eggert@cs.ucla.edu> writes:

> Michael Heerdegen wrote:
> > The problem is that (aref xlfd-fields xlfd-regexp-pixelsize-subnum)
> > returns nil which I guess is not correct.
>
> Thanks for this example. However, it relies on some stuff from Drew
> Adams that is not part of Emacs.

Yes, and I'm also not sure if this problem is related, though I guess it
could likely be.

> Can you please give a self-contained example of how to reproduce the
> problem? (If the first step is "download foo from bar", that's fine;
> however, I couldn't easily figure out how to download Adams's code
> from his wiki, as a page seems to be missing.)

Just install the "frame-fns" and "frame-cmds' Gnu Elpa packages.  Load
them in this order, then eval (enlarge-font 1).

> Also, what platform are you running on, and have you configured your
> fonts in any way?

(emacs-version) 
==>
"GNU Emacs 27.0.50 (build 15, x86_64-pc-linux-gnu, GTK+ Version
3.22.30)\n of 2018-08-29"

master build from today.  Debian Linux.  I have not configured fonts in
any way AFAICT.  Don't know much about this stuff.  I just noticed that
`enlarge-font' stopped working some days ago, and reverting to the
commit that has been mentioned made the problem go away.
`text-scale-adjust' works normally OTOH.

Anything else I can do?


Thanks,

Michael.

Re: Recent changes incorrectly calculate font size within daemon mode

[Paul Eggert]

Michael Heerdegen wrote:

> Just install the "frame-fns" and "frame-cmds' Gnu Elpa packages.  Load
> them in this order, then eval (enlarge-font 1).

I don't use GNU ELPA so I'm afraid you'll have to walk me through this. If I 
start with 'src/emacs -Q', what should I type? (I did try to figure this out on 
my own and gave up; evidently there's a GNU ELPA howto somewhere that I didn't 
find).

Re: Recent changes incorrectly calculate font size within daemon mode

[Michael Heerdegen]

Paul Eggert <eggert@cs.ucla.edu> writes:

> I don't use GNU ELPA so I'm afraid you'll have to walk me through
> this.

Drew has posted direct links some minutes ago:

  https://www.emacswiki.org/emacs/download/frame-fns.el

  https://www.emacswiki.org/emacs/download/frame-cmds.el

Just download the files with wget or the "save as" dialog in your
browser.  Load them in this order in emacs -Q, then eval (enlarge-font
1).


Michael.

Re: Recent changes incorrectly calculate font size within daemon mode

[Michael Heerdegen]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> > I don't use GNU ELPA so I'm afraid you'll have to walk me through
> > this.
>
> Drew has posted direct links some minutes ago:
>
>   https://www.emacswiki.org/emacs/download/frame-fns.el
>
>   https://www.emacswiki.org/emacs/download/frame-cmds.el
>
> Just download the files with wget or the "save as" dialog in your
> browser.  Load them in this order in emacs -Q, then eval (enlarge-font
> 1).

The crucial difference seems to be that in an older Emacs build I get

(assq 'font (frame-parameters))
==>
 (font . "-PfEd-DejaVu Sans Mono-normal-normal-normal-*-23-*-*-*-m-0-iso10646-1")

and with current master

(assq 'font (frame-parameters))
==>
 (font . "-PfEd-DejaVu Sans Mono-normal-normal-normal-*-*-*-*-*-m-0-iso10646-1")

The "23" seems to be missing (font pixels size I guess) for what
`enlarge-font' does.


Michael.

Re: Recent changes incorrectly calculate font size within daemon mode

[Paul Eggert]

[-- Attachment #1: Type: text/plain, Size: 510 bytes --]

Michael Heerdegen wrote:
> The crucial difference seems to be that in an older Emacs build I get
> 
> (assq 'font (frame-parameters))
> ==>
>   (font . "-PfEd-DejaVu Sans Mono-normal-normal-normal-*-23-*-*-*-m-0-iso10646-1")
> 
> and with current master
> 
> (assq 'font (frame-parameters))
> ==>
>   (font . "-PfEd-DejaVu Sans Mono-normal-normal-normal-*-*-*-*-*-m-0-iso10646-1")

Thanks for narrowing that down; it was quite helpful. I installed the attached 
patch into Emacs master; please give it a try.


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-Fix-off-by-1-typo-in-recent-bignum-changes.patch --]
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From 260e695dedd1cf9b9815a38e6b3369319b97b5f9 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 30 Aug 2018 14:28:19 -0700
Subject: [PATCH] Fix off-by-1 typo in recent bignum changes
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Problem reported by Yuri D’Elia in:
https://lists.gnu.org/r/emacs-devel/2018-08/msg00977.html
and crucial clue provided by Michael Heerdegen in:
https://lists.gnu.org/r/emacs-devel/2018-08/msg01043.html
* src/font.c (font_unparse_xlfd): Fix off-by-1 typo.
---
 src/font.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/font.c b/src/font.c
index 4a63700f79..e2414582f6 100644
--- a/src/font.c
+++ b/src/font.c
@@ -1290,7 +1290,7 @@ font_unparse_xlfd (Lisp_Object font, int pixel_size, char *name, int nbytes)
   if (INTEGERP (val))
     {
       intmax_t v = FIXNUMP (val) ? XFIXNUM (val) : bignum_to_intmax (val);
-      if (! (0 <= v && v <= TYPE_MAXIMUM (uprintmax_t)))
+      if (! (0 < v && v <= TYPE_MAXIMUM (uprintmax_t)))
 	v = pixel_size;
       if (v > 0)
 	{
-- 
2.17.1

Re: Recent changes incorrectly calculate font size within daemon mode

[Michael Heerdegen]

Paul Eggert <eggert@cs.ucla.edu> writes:

> I installed the attached patch into Emacs master; please give it a
> try.

That fixed it for me.  Thank you very much!

Regards,

Michael.

Re: Recent changes incorrectly calculate font size within daemon mode

[Yuri D'Elia]

On Thu, Aug 30 2018, Paul Eggert wrote:
> Thanks for narrowing that down; it was quite helpful. I installed the
> attached patch into Emacs master; please give it a try.

I can confirm this also fixes the issue for me as well.
Thanks for looking into this!

Re: Recent changes incorrectly calculate font size within daemon mode

[Stefan Monnier]

> Just install the "frame-fns" and "frame-cmds' Gnu Elpa packages.

There's no such thing, sorry.

Maybe there are ELPA packages with such names, but definitely not in GNU
ELPA, as you can check at http://elpa.gnu.org/packages/


        Stefan

Re: Recent changes incorrectly calculate font size within daemon mode

[Michael Heerdegen]

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

> > Just install the "frame-fns" and "frame-cmds' Gnu Elpa packages.
>
> There's no such thing, sorry.
>
> Maybe there are ELPA packages with such names, but definitely not in GNU
> ELPA, as you can check at http://elpa.gnu.org/packages/

Yes, what I thought to remember was wrong.  They are neither in Gnu Elpa
nor in Melpa.


Michael.

RE: Recent changes incorrectly calculate font size within daemon mode

[Drew Adams]

> Michael Heerdegen wrote:
> > The problem is that (aref xlfd-fields xlfd-regexp-pixelsize-subnum)
> > returns nil which I guess is not correct.
> 
> Thanks for this example. However, it relies on some stuff from Drew Adams
> that is not part of Emacs. Can you please give a self-contained example of how to
> reproduce the problem? (If the first step is "download foo from bar", that's
> fine; however, I couldn't easily figure out how to download Adams's code
> from his wiki, as a page seems to be missing.)'

Adams does not have a wiki. ;-)  The code is on Emacs Wiki, at the regular
download location (Elisp Area):

https://www.emacswiki.org/emacs?action=elisp-area;context=0

Download frame-fns.el and frame-cmds.el, and load them in that order.
The function that uses (aref xlfd-fields xlfd-regexp-pixelsize-subnum) is
`frcmds-enlarged-font-name':

(defun frcmds-enlarged-font-name (fontname frame increment)
  "FONTNAME, after enlarging font size of FRAME by INCREMENT.
FONTNAME is the font of FRAME."
  (when (query-fontset fontname)
    (let ((ascii  (assq 'ascii (aref (fontset-info fontname frame) 2))))
      (when ascii (setq fontname  (nth 2 ascii)))))
  (let ((xlfd-fields  (x-decompose-font-name fontname)))
    (unless xlfd-fields (error "Cannot decompose font name"))
    (let ((new-size  (+ (string-to-number (aref xlfd-fields xlfd-regexp-pixelsize-subnum))
                        increment)))
      (unless (> new-size 0) (signal 'font-too-small (list new-size)))
      (aset xlfd-fields xlfd-regexp-pixelsize-subnum (number-to-string new-size)))
    ;; Set point size & width to "*", so frame width will adjust to new font size
    (aset xlfd-fields xlfd-regexp-pointsize-subnum "*")
    (aset xlfd-fields xlfd-regexp-avgwidth-subnum "*")
    (x-compose-font-name xlfd-fields)))

https://www.emacswiki.org/emacs/download/frame-fns.el

https://www.emacswiki.org/emacs/download/frame-cmds.el