Re: strange space width jumping in header lines

[Gavin Smith]

On Fri, Sep 16, 2022 at 06:18:09AM +0000, Werner LEMBERG wrote:
> 
> [texinfo.tex version 2022-09-15.17]
> 
> 
> I noticed that for unknown reasons the space width between
> 'Chapter X:' and the following text in the header line varies; see
> attached images.  Unfortunately, I can't see any logic behind it,
> which makes it hard for me to provide a minimum example.

Have you looked at what font and environment is current at the bottom
of the page when it happens?

I managed to replicate it using @code:

\input texinfo

@everyheading @thischapter @Debug{}

@tex
\gdef\Debug{%
(Colon space factor \the\sfcode`\:)%
}
@end tex

@chapter One

@code{aaa @page bbb}

@bye

(It's a subtle difference - I could only see it by opening two PDF readers
at once and flipping back and forth between the two.)

You can see that @code changes the space factor of colon and this is not
altered inside the heading.

I've commited a change (version 2022-09-17.11) that should fix this,
at the expense of some extra processing every page to reset the
space factor codes.  If this is a significant performance hit then
I could redo this to be more efficient, only resetting the codes
when necessary.

> It might also manifest because we use some extra code to replace CM
> typewriter with LMMonoLt10 – for the LilyPond documentation we need
> both a bold and a bold slanted typewriter face to have proper pygments
> support within LilyPond code snippets.

It doesn't seem that any of this makes a difference to the issue.