bug#43148: 27.1; Widget text seems to disappear when building with Cairo and Xaw

[YAMAMOTO Mitsuharu]

On Tue, 01 Dec 2020 22:10:32 +0900,
tastytea wrote:
> 
> On 2020-11-28 17:22+0900 YAMAMOTO Mitsuharu
> <mituharu@math.s.chiba-u.ac.jp> wrote:
> 
> > On Wed, 25 Nov 2020 11:30:07 +0900,
> > Basil L. Contovounesios wrote:
> > > 
> > > Robert Pluim <rpluim@gmail.com> writes:
> > >   
> > > >>>>>> On Tue, 01 Sep 2020 17:09:18 +0300, Eli Zaretskii
> > > >>>>>> <eliz@gnu.org> said:  
> > > >  
> > > >     >> From: Pouar Dragon <pouar@pouar.net>
> > > >     >> Date: Mon, 31 Aug 2020 21:34:46 -0500
> > > >     >> 
> > > >     >> widgets when building with Xaw and Cairo seem to have
> > > >     >> missing text, looking like this
> > > >     >> 
> > > >     >> problem seems to go away when
> > > >     >> 5f4e8e2e088de9fb76cb631077c6eddd3219f594 is reverted  
> > > >  
> > > >     Eli> Thanks.  I hope Yamamoto-san will be able to take a look
> > > >     Eli> at this.  
> > > >
> > > > Putting on my 'let's simplify' hat, is this really a combination
> > > > we want to spend time on? Lucid + Xaw + Cairo is decidedly
> > > > non-mainstream (Iʼm surprised it even builds).  
> > > 
> > > FWIW, I've been happily using Lucid + Xaw3D for several years, and
> > > Cairo ever since it became stable in Emacs 27 and the default
> > > configuration in Emacs 28.
> > > 
> > > I usually have menu-bar-mode off, but like other reports in this
> > > thread, the menus look fine when I do open them, e.g. after 'emacs
> > > -Q'.
> > > 
> > > Could the issue depend on e.g. the version of Cairo?  (I seem to
> > > have an older version than the OP.)  
> > 
> > Possibly.  The OP seems to use cairo 1.17.3, which is not a release
> > version (the latest is 1.16.0) and even not the snapshot one (the
> > latest is 1.17.2 according to https://cairographics.org).
> 
> I experience the same issue as the OP with lucid and cairo 1.16.0,
> with and without xaw3d, on Gentoo Linux. The problem goes away if I
> disable cairo.
> The same happens with 28.0.50, commit
> 1a3aa6043a51e5bb4007889dd7dcabb55dc44132.

So, only digits are shown with "$ emacs -Q" ?
Could you show us the output of "$ fc-match -s sans" ?

I tried the latest snapshot cairo 1.17.4 on XQuartz/macOS, and I don't
see any problems.  On my side, "$ fc-match -s sans" reports Arial
Unicode.ttf at the first line.

                                     YAMAMOTO Mitsuharu
                                mituharu@math.s.chiba-u.ac.jp