bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[Markus Triska]

In the Emacs man page, we find for the "-g" (--geometry) option:

    The width and height are specified in characters; the default is
    80 by 24.

In the Emacs info page ("C.8 Options for Window Size and Position"), we
find a different default height:

   The default frame width is 80 characters and the default height is
   40 lines.

However, when I start Emacs via "$ emacs -Q", I actually get a height
that is neither 24 nor 40, no matter how I count it: On a recent Debian
install with X toolkit, I get an initial window that comprises exactly
28 lines, and if I include the mode line and echo area, then the frame
height is 30, excluding the tool bar, menu bar and title bar.



In GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, X toolkit, Xaw scroll bars)
 of 2018-12-30 built on stretch
Repository revision: b0e6ecfc33077fb2dce904d315c8ef24e3649c9b
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.11604000
System Description: Debian GNU/Linux 9 (stretch)

Recent messages:
Loading /home/mt/prolog.el (source)...done
Loading /home/mt/public_html/ediprolog/ediprolog.el (source)...done
For information about GNU Emacs and the GNU system, type C-h C-a.
Use +,-,0 for further adjustment [2 times]

Configured using:
 'configure --with-x-toolkit=lucid --with-gif=no --with-tiff=no'

Configured features:
XPM JPEG PNG SOUND NOTIFY INOTIFY GNUTLS FREETYPE XFT ZLIB
TOOLKIT_SCROLL_BARS LUCID X11 XDBE XIM THREADS GMP

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  value of $LANG: en_US.utf8
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
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bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[martin rudalics]

 > In the Emacs man page, we find for the "-g" (--geometry) option:
 >
 >      The width and height are specified in characters; the default is
 >      80 by 24.

This must be a very old entry.

 > In the Emacs info page ("C.8 Options for Window Size and Position"), we
 > find a different default height:
 >
 >     The default frame width is 80 characters and the default height is
 >     40 lines.

The default height was changed from 40 to 35 by Chong and from 35 to
36 by Eli.  I now updated the value given by the manual of the release
branch.

 > However, when I start Emacs via "$ emacs -Q", I actually get a height
 > that is neither 24 nor 40, no matter how I count it: On a recent Debian
 > install with X toolkit, I get an initial window that comprises exactly
 > 28 lines,

28 lines is strange indeed.

 > and if I include the mode line and echo area, then the frame
 > height is 30, excluding the tool bar, menu bar and title bar.

Evaluating (frame-height) with emacs -Q should yield 36.  What does it
give for you?  And what is your value of (window-total-height) for the
initial window?  It's 35 here.

martin

bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[Eli Zaretskii]

> Date: Sun, 30 Dec 2018 15:57:47 +0100
> From: martin rudalics <rudalics@gmx.at>
> 
>  > In the Emacs man page, we find for the "-g" (--geometry) option:
>  >
>  >      The width and height are specified in characters; the default is
>  >      80 by 24.
> 
> This must be a very old entry.
> 
>  > In the Emacs info page ("C.8 Options for Window Size and Position"), we
>  > find a different default height:
>  >
>  >     The default frame width is 80 characters and the default height is
>  >     40 lines.
> 
> The default height was changed from 40 to 35 by Chong and from 35 to
> 36 by Eli.  I now updated the value given by the manual of the release
> branch.

I actually think we shouldn't promise any concrete value, and instead
say something vague, like "between 35 and 40, depending on the OS and
the window manager".

bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[martin rudalics]

 > I actually think we shouldn't promise any concrete value, and instead
 > say something vague, like "between 35 and 40, depending on the OS and
 > the window manager".

The value of evaluating (frame-height) should be 36 if nothing special
has been specified.  There are still some unclosed bug reports
(Bug#16013) revolving around how to specify the initial size of a
frame.  But the values given by DEFAULT_ROWS and DEFAULT_COLS should
work in a uniform way for every GUI frame regardless of OS and window
manager.

So before becoming vague let's wait until we have a report (maybe the
present one) that demonstrates that a value of 36 cannot be obtained.

martin

bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[Markus Triska]

martin rudalics <rudalics@gmx.at> writes:

> Evaluating (frame-height) with emacs -Q should yield 36.  What does it
> give for you?  And what is your value of (window-total-height) for the
> initial window?  It's 35 here.

(frame-height) yields 29, and (window-total-height) yields 28.

When I run (set-frame-height nil 36), then (frame-height) yields 36.

So, it's possible to obtain this frame height, and ideally this should
also be obtainable with the "-g" option.

I tried all this with the window manager FVWM as shipped with Debian.

bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[Eli Zaretskii]

> Date: Sun, 30 Dec 2018 18:47:01 +0100
> From: martin rudalics <rudalics@gmx.at>
> CC: triska@metalevel.at, 33921@debbugs.gnu.org
> 
>  > I actually think we shouldn't promise any concrete value, and instead
>  > say something vague, like "between 35 and 40, depending on the OS and
>  > the window manager".
> 
> The value of evaluating (frame-height) should be 36 if nothing special
> has been specified.

That's definitely not true for TTY frames.

> So before becoming vague let's wait until we have a report (maybe the
> present one) that demonstrates that a value of 36 cannot be obtained.

Fine with me, but I'd be very surprised if we conclude that 36 is an
accurate number in enough situations to cite it in the manual.

bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[martin rudalics]

 >> Evaluating (frame-height) with emacs -Q should yield 36.  What does it
 >> give for you?  And what is your value of (window-total-height) for the
 >> initial window?  It's 35 here.
 >
 > (frame-height) yields 29, and (window-total-height) yields 28.

Hmm... then it's not even vague according to Eli.  I'm afraid you have
to use the debugger to find out what goes wrong.  For starters I would
set a breakpoint at the beginning of x_figure_window_size (in frame.c)
and check whether any height setting gets applied.

 > When I run (set-frame-height nil 36), then (frame-height) yields 36.
 >
 > So, it's possible to obtain this frame height, and ideally this should
 > also be obtainable with the "-g" option.
 >
 > I tried all this with the window manager FVWM as shipped with Debian.

If FVWM interferes we will find out soon enough.

martin

bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[martin rudalics]

 >> The value of evaluating (frame-height) should be 36 if nothing special
 >> has been specified.
 >
 > That's definitely not true for TTY frames.

I mentioned the GUI restriction a few lines below.

 > Fine with me, but I'd be very surprised if we conclude that 36 is an
 > accurate number in enough situations to cite it in the manual.

It's a default we specify explicitly.  When OS or WM interfere all
bets are off obviously.

martin

bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

>> Date: Sun, 30 Dec 2018 15:57:47 +0100
>> From: martin rudalics <rudalics@gmx.at>
>> 
>>  > In the Emacs man page, we find for the "-g" (--geometry) option:
>>  >
>>  >      The width and height are specified in characters; the default is
>>  >      80 by 24.
>> 
>> This must be a very old entry.
>> 
>>  > In the Emacs info page ("C.8 Options for Window Size and Position"), we
>>  > find a different default height:
>>  >
>>  >     The default frame width is 80 characters and the default height is
>>  >     40 lines.
>> 
>> The default height was changed from 40 to 35 by Chong and from 35 to
>> 36 by Eli.  I now updated the value given by the manual of the release
>> branch.
>
> I actually think we shouldn't promise any concrete value, and instead
> say something vague, like "between 35 and 40, depending on the OS and
> the window manager".

I've now made this change.

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