bug#31203: 26.1; Fringe and toolbar bitmaps unscaled on Windows 10 HiDPI display

bug#31203: 26.1; Fringe and toolbar bitmaps unscaled on Windows 10 HiDPI display

[Keith Russell]

Running on Windows 10 with a high resolution display (3840 x 2160)
the fringe bitmaps and toolbar buttons are so tiny as to be almost
indistinguishable from dots. Scrollbars and menus are fine and the
fonts look stunning. If I set the compatibility option to "override
application" and let the system scale then it's the right size but
fuzzy. I couldn't find anything in the bug reports. The only
thing I found in the Changelog was the change to make Emacs
DPI aware on Windows but that was back in 2015.


In GNU Emacs 26.1 (build 1, x86_64-w64-mingw32)
  of 2018-04-10 built on CIRROCUMULUS
Repository revision: c267421647510319d2a70554e42f0d1c394dba0a
Windowing system distributor 'Microsoft Corp.', version 10.0.16299
Recent messages:
; is undefined
Finding changes in ....
Commands: d, s, x, u; f, o, 1, 2, m, v; ~, %; q to quit; ? for help.
(Wraparound for next marked file)
dired-next-marked-file: No next marked file
M-ESC C-M-p is undefined
Mark saved where search started
Grep finished with 265 matches found
Parsing gtkutil.c (LL)...done
Parsing image.c (LL)...done

Configured using:
  'configure --without-dbus --host=x86_64-w64-mingw32
  --without-compress-install 'CFLAGS=-O2 -static -g3''

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS THREADS LCMS2

Important settings:
   value of $LANG: ENC
   locale-coding-system: cp1252

Major mode: C/*l

Minor modes in effect:
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Load-path shadows:
None found.

Features:
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bug#31203: 26.1; Fringe and toolbar bitmaps unscaled on Windows 10 HiDPI display

[Eli Zaretskii]

> From: Keith Russell <keithrussell42@fastmail.com>
> Date: Tue, 17 Apr 2018 21:07:34 -0400
> 
> 
> Running on Windows 10 with a high resolution display (3840 x 2160)
> the fringe bitmaps and toolbar buttons are so tiny as to be almost
> indistinguishable from dots. Scrollbars and menus are fine and the
> fonts look stunning. If I set the compatibility option to "override
> application" and let the system scale then it's the right size but
> fuzzy. I couldn't find anything in the bug reports. The only
> thing I found in the Changelog was the change to make Emacs
> DPI aware on Windows but that was back in 2015.

The fringe bitmaps have fixed width specified in pixels.  I understand
you are saying that the number of pixels is correct, but its visual
appearance leaves a lot to be desired, is that right?  If so, you can
customize your fringes using this:

  (setq fringe-mode '(16 . 16))

(replace 16 with a number that is to your liking, I'm just guessing
there).

We could also apply the scaling automatically, patches welcome.

bug#31203: 26.1; Fringe and toolbar bitmaps unscaled on Windows 10 HiDPI display

[Keith Russell]

[-- Attachment #1: Type: text/plain, Size: 1617 bytes --]

Hi Eli,

Unfortunately that only changes the width of the fringe. I had tried it 
before but tried again just to make sure. The bitmap doesn't scale with 
the fringe width. See the attached screen shot. This is with a fringe of 
32 and a font of "10" which translates to 33 pixels on my display. I'm 
not a Windows programmer (more Linux than anything) so I'm not sure if I 
can provide a patch. I will poke around the source and see what I can 
see. Maybe something obvious will pop out.

Thanks,

Keith


On 2018-04-18 2:54, Eli Zaretskii wrote:
>> From: Keith Russell <keithrussell42@fastmail.com>
>> Date: Tue, 17 Apr 2018 21:07:34 -0400
>>
>>
>> Running on Windows 10 with a high resolution display (3840 x 2160)
>> the fringe bitmaps and toolbar buttons are so tiny as to be almost
>> indistinguishable from dots. Scrollbars and menus are fine and the
>> fonts look stunning. If I set the compatibility option to "override
>> application" and let the system scale then it's the right size but
>> fuzzy. I couldn't find anything in the bug reports. The only
>> thing I found in the Changelog was the change to make Emacs
>> DPI aware on Windows but that was back in 2015.
> The fringe bitmaps have fixed width specified in pixels.  I understand
> you are saying that the number of pixels is correct, but its visual
> appearance leaves a lot to be desired, is that right?  If so, you can
> customize your fringes using this:
>
>    (setq fringe-mode '(16 . 16))
>
> (replace 16 with a number that is to your liking, I'm just guessing
> there).
>
> We could also apply the scaling automatically, patches welcome.


[-- Attachment #2: emacs-fringe.PNG --]
[-- Type: image/png, Size: 20422 bytes --]

bug#31203: 26.1; Fringe and toolbar bitmaps unscaled on Windows 10 HiDPI display

[Eli Zaretskii]

> Cc: 31203@debbugs.gnu.org
> From: Keith Russell <keithrussell42@fastmail.com>
> Date: Wed, 18 Apr 2018 19:55:33 -0400
> 
> Unfortunately that only changes the width of the fringe. I had tried it 
> before but tried again just to make sure. The bitmap doesn't scale with 
> the fringe width. See the attached screen shot. This is with a fringe of 
> 32 and a font of "10" which translates to 33 pixels on my display. I'm 
> not a Windows programmer (more Linux than anything) so I'm not sure if I 
> can provide a patch. I will poke around the source and see what I can 
> see. Maybe something obvious will pop out.

Thanks.  I wonder why this problem was not reported on X.  Maybe the
relevant X APIs scale the bitmaps under the hood?

bug#31203:

[Carlos Pita]

Hi Eli, not sure about the fringe pixmaps, but I can confirm that many
things are scaled too tiny in X11 with a hidpi screen, for example
checkboxes and "subtree arrows" in customization buffers. Also tetris
looks absurdly tiny. In general, I would say that widgets and images
are not correctly scaled according to the screen dpi. It also
surprises me that there are so few google/debbugs matches when
searching for hidpi related problems. Everyone is moving to 2K and 3K
screens now, you can't buy new decent lowdpi hardware even if you
wanted to.

bug#31203:

[Carlos Pita]

> looks absurdly tiny. In general, I would say that widgets and images
> are not correctly scaled according to the screen dpi. It also

I mean non-GTK widgets, the ones rendered by emacs itself.

bug#31203:

[Carlos Pita]

Now I can confirm the tiny fringe indicators in X11 too:

* Emacs 26.1
* Ubuntu 19.04