Re: microtype for texinfo

[pertusus]

On Tue, Sep 27, 2022 at 08:20:17PM +0100, Gavin Smith wrote:
> On Tue, Sep 27, 2022 at 09:38:30AM +0200, pertusus@free.fr wrote:
> > ... but my feeling is
> > that this is the symptom of something wrong being done with fonts
> > selection in the LaTeX output, not an issue with microtype as such.
> 
> It is just a consequence of using T1 encoded fonts, which aren't used
> everywhere in texinfo.tex, only for special characters.  In the LaTeX
> the T1 encoded fonts have to be used everywhere otherwise @DH{} and the
> like don't work.  There's no easy way to use a different font for @DH{}
> specially without providing our own definitions of these glyph commands.
> See where \ecfont is used in texinfo.tex.

Ok, thanks.  That means that we could make different choices with
respect to microtype.  But I think that we should prominently document
that it is very much advidsed to have cm-super installed, for some
glyphs in Texinfo TeX, as it is already documented, and for the whole
document for LaTeX output.

> > On my debian I can remove the cm-super
> > package and also the cm-super-minimal package and texi2pdf still works
> > well and produces ogonek accented characters.
> 
> Do @DH{} and other glyph commands work?

Yes, but bitmap fonts are used.

> In texinfo.tex, a different font is used for ogonek for certain letters
> only - A, a, E, e.  Did you test it with one of those characters?

I tested with:
ð @th{} þ a @'e é @DH{} @ogonek{a} @ogonek{b}

'a' and 'é' are always rendered with a scalable font.  When cm-super is
installed, all the glyphs are rendered with a scalable font, including
@ogonek{b}.  When cm-super is not installed, all the glyphs (except for
'a' and 'é') use bitmap fonts (my criteria is that they pixelate when I
zoom).

In documents with lot of glyphs like that, and with cm-super not installed,
there could be a risk to get the microtype error with Texinfo TeX I get
with LaTeX output:
pdfTeX error (font expansion): auto expansion is only possible with scalable 
fonts.

-- 
Pat