FAQ: add entry about color emoji Xft bug (bbb3e5)

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bakkeby 2020-03-24 13:54:27 +01:00
parent 78d1d7c181
commit a15712c2e6

27
FAQ
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@ -165,3 +165,30 @@ Apply [1].
[1] http://st.suckless.org/patches/delkey
## BadLength X error in Xft when trying to render emoji
Xft makes st crash when rendering color emojis with the following error:
"X Error of failed request: BadLength (poly request too large or internal Xlib length error)"
Major opcode of failed request: 139 (RENDER)
Minor opcode of failed request: 20 (RenderAddGlyphs)
Serial number of failed request: 1595
Current serial number in output stream: 1818"
This is a known bug in Xft (not st) which happens on some platforms and
combination of particular fonts and fontconfig settings.
See also:
https://gitlab.freedesktop.org/xorg/lib/libxft/issues/6
https://bugs.freedesktop.org/show_bug.cgi?id=107534
https://bugzilla.redhat.com/show_bug.cgi?id=1498269
The solution is to remove color emoji fonts or disable this in the fontconfig
XML configuration. As an ugly workaround (which may work only on newer
fontconfig versions (FC_COLOR)), the following code can be used to mask color
fonts:
FcPatternAddBool(fcpattern, FC_COLOR, FcFalse);
Please don't bother reporting this bug to st, but notify the upstream Xft
developers about fixing this bug.