Re: describe-{function,variable} shrinks frame (GTK+/KDE)

[Stephen Berman <Stephen.Berman@gmx.net>]

On Sun, 18 Nov 2007 10:33:32 +0100 martin rudalics <rudalics@gmx.at> wrote:

>> I invoked this and frame-height diminished by one line after the first
>> interactive call.
>
> That is after the sit-for and before the `delete-other-windows'
>
>      (sit-for 0.5)
>      (delete-other-windows)
>
> your frame has got smaller by one line?  

By stepping through srb-shrink-test-1 with edebug, I have seen the
reduction in frame-height occur in two places (on two different
invocations of srb-shrink-test-1 after emacs -Q): as above, after the
(sit-for 0.5) that immediately precedes (delete-other-windows), but also
after the (sit-for 0.5) that follows (delete-other-windows).

>                                          The fact that it gets smaller
> by _one_ line and Info is involved might relate this to the header line.
> Unfortunately, it seems impossible to turn that line off by setting
> `Info-use-header-line', so I don't know how to test this.  

I loaded the info library, did `M-x customize-variable RET
Info-use-header-line RET', clicked it to off with toggle button and set
it for the current session.  Then I invoked srb-shrink-test-1 and the
Info buffer came up without a header line (C-h v header-line-format in
that buffer said its value is nil).  Did you do the same thing and get a
different result, or did you do something else?  

Anyway, even without the Info header line, frame-height got reduced by
one line just as with the header line.  I also tried just loading info
and running srb-shrink-test-1 with the line (info) commented out: in
this case, frame-height did not change.

>                                                            You could try
> with a non-Info buffer displaying a header-line.

I tried variants of srb-shrink-test-1, respectively replacing (info)
with (ruler-mode 1), (tabbar-mode 1) (tabbar.el is an external library
that sets up a tabbed header line), and (setq header-line-format
"TEST"), but in each case frame-height did not change.  It seems that
the header line is not relevant, but invoking info is.

>> I have repeated this many times and every time
>> frame-height has shrunk, whereas with srb-shrink-test-0 it has never
>> shrunk.  It seems that call-interactively is somehow involved in
>> shrinking frame-height.  I looked at the source code but found nothing
>> suggestive; but it is a very long and complex function, and I don't know
>> what to look for.  It doesn't help that this problem seems to be
>> restricted to GTK+ builds running under gtk-qt.
>
> Maybe it's related to the KDE frame resizing problem you mentioned
> earlier 

I strongly suspect this is the case.  Unfortunately, I know nothing
about the gtk-qt engine and it seems that none of the core Emacs
developers uses it.

>         (I suppose you still get that after the merge).  

Yes, unfortunately.

>                                                          Does changing
> the font and/or changing the Info faces affect the behavior?

The frame-height reduction happens both with -Q as well as with my
personal settings, which use a different font.  I also tried it after
setting all the oversized Info faces to default and still got the
frame-height reduction.

Steve Berman