In article <87po9irqej.fsf@gmx.net>, Stephen Berman <stephen.berman@gmx.net> writes:

> I haven't yet tried a font specialized for Lao, but I did try Symbola,
> and with that the Lao HELLO example appears as it does in Emacs without
> m17n-lib and libotf (with one exeption, see below) -- though the font
> used to display the Lao is not Symbola but DejaVu Sans.  Then I realized
> what the difference is: Symbola is a variable pitch font, while my
> default font is DejaVu Sans Mono (also the default with -Q).  And
> indeed, using DejaVu Sans (not Mono) as the default font displays the
> Lao as in Emacs without m17n-lib and libotf (but in the latter Emacs
> it's the same display also with DejaVu Sans Mono) -- with the exception
> of the character LAO LETTER HO SUNG, which is composed with LAO TONE MAI
> THO, but in the display, the latter appears over the following
> character, while in the Emacs without m17n-lib and libotf it appears
> over the character it is composed with (which I assume is correct).  The
> other three character compositions in the Lao example appear the same in
> Emacs both without and with m17n-lib and libotf -- but again, in the
> latter only with variable pitch DejaVu Sans.  So this does seem to be a
> problem in the m17n-lib and/or libotf code.

In my environment, Lao can be rendered correctly by Dejavu Sans Mono
(see the attached image).  Please run Emacs as this, and show me the
printed log:

% MDEBUG_DATABASE=1 MDEBUG_FLT=1 emacs

---
K. Handa
handa@gnu.org