Re: cairo now default?

[Colin Baxter]

>>>>> Robert Pluim <address@hidden> writes:

>>>>> On Tue, 28 Jan 2020 10:13:58 +0000, Colin Baxter <address@hidden> said:
    Colin> I notice that ./configure <RET> configures the build to use
    Colin> cairo and not to use HarfBuzz. Perhaps I'm mistaken, I don't
    Colin> remember cairo as default. Users now have presumably to
    Colin> specify --without-cairo. Also I seem to recall someone here
    Colin> saying that HarfBuzz should be used when cairo is used.

    > Did configure not say that at the end? I guess you donʼt have
    > HarfBuzz headers installed, they're used if they're found.

    > configure.ac:

    >     if test "${HAVE_CAIRO}" = "yes" && test "${HAVE_HARFBUZZ}" =
    > no; then AC_MSG_WARN([This configuration uses the Cairo graphics
    > library, but not the HarfBuzz font shaping library.  We recommend
    > the use of HarfBuzz when using Cairo, please install HarfBuzz
    > development packages.])  fi

    > etc/NEWS:

    >     * Installation Changes in Emacs 28.1

    >     ** Cairo graphics library is now used by default if found.
    > '--with-cairo' is now the default, if the appropriate development
    > files are found by 'configure'.  Note that building with Cairo
    > means using Pango instead of libXFT for font support.  Since Pango
    > 1.44 has removed support for bitmapped fonts, this may require you
    > to adjust your font settings.

    >     Note also that 'FontBackend' settings in ".Xdefaults" or
    > ".Xresources", or 'font-backend' frame parameter settings in your
    > init files, may need to be adjusted, as 'xft' is no longer a valid
    > backend when using Cairo.  Use 'ftcrhb' if your Emacs was built
    > with HarfBuzz text shaping support, and 'ftcr' otherwise.  You can
    > determine this by checking 'system-configuration-features'.  The
    > 'ftcr' backend will still be available when HarfBuzz is supported,
    > but will not be used by default.  We strongly recommend building
    > with HarBuzz support. 'x' is still a valid backend.

The configure warning:

"This configuration uses the Cairo graphics library,
but not the HarfBuzz font shaping library.  We recommend the use
of HarfBuzz when using Cairo, please install HarfBuzz development
packages."

occurs at the end of the list of configured options and then scrolls up
disappearing from the screen before the configure command ends. It's
easily missed and the user who doesn't have HarfBuzz ends up puzzled,
with a working emacs but one that looks unfamiliar and ugly.

If cairo has to be the default - and I don't understand why - is this
going to be emphasised in the INSTALL file of the subsequent distribution?

Best wishes,