Re: Display of Lao script

[Stephen Berman <stephen.berman@gmx.net>]

On Tue, 24 Oct 2017 18:14:01 +0900 handa <handa@gnu.org> wrote:

> In article <877evnqvu4.fsf@gmx.net>, Stephen Berman <stephen.berman@gmx.net> writes:
>
>> In your screen shot the displays of the Kannada, Khmer and Malayalam
>> examples are partly different from the displays in my Emacs:
>
> That is because I didn't install proper fonts for those scripts.
>
> Anyway, the log has these suspicious lines:
>  [DB] <font,layouter,laoo-generic,nil> from /usr/share/m17n/LAOO-GENERIC.flt
>  [FLT] (laoo-generic (dejavu sans mono)
>  [FLT]   (SOURCE 0E94 0EB5)
>  [FLT]   (RESULT 04BA 04D4))
>
> In my case, the first line is:
>  [DB] <font,layouter,laoo-otf,nil> from /usr/share/m17n/LAOO-OTF.flt
>
> I have not yet figured out why LAOO-OTF.flt is not selected for you, but
> could you please try this:
>
> 1. Move LAOO-*.flt (except for LAOO-OTF.flt) from /usr/share/m17n to,
>    for instance /tmp.
> 2. Prepare a file that contains the Lao line only.
> 3. Run emacs as this:
>    % MDEBUG_DATABASE=1 MDEBUG_FLT=3 emacs
> 4. Visit the Lao only file.

I did this and the display of the Lao script is the same as before
(i.e., with the composed characters not properly aligned).  Here is the
entire debugging output:

 [DB]  <font,layouter,hebr,nil>.
 [DB]  <font,layouter,mlym-rachana,nil>.
 [DB]  <font,layouter,thai-norasi,nil>.
 [DB]  <font,layouter,bng2-otf,nil>.
 [DB]  <font,layouter,hebr-otf,nil>.
 [DB]  <font,layouter,tml2-otf,nil>.
 [DB]  <font,layouter,orya-otf,nil>.
 [DB]  <font,layouter,ory2-otf,nil>.
 [DB]  <font,layouter,mymr-myazedi,nil>.
 [DB]  <font,layouter,mlym-otf,nil>.
 [DB]  <font,layouter,knd2-otf,nil>.
 [DB]  <font,layouter,tel2-otf,nil>.
 [DB]  <font,layouter,syrc-otf,nil>.
 [DB]  <font,layouter,arab-otf,nil>.
 [DB]  <font,layouter,mlym-cdac,nil>.
 [DB]  <font,layouter,taml-otf,nil>.
 [DB]  <font,layouter,knda-otf,nil>.
 [DB]  <font,layouter,gujr-otf,nil>.
 [DB]  <font,layouter,deve-cdac,nil>.
 [DB]  <font,layouter,guru-otf,nil>.
 [DB]  <font,layouter,arab,nil>.
 [DB]  <font,layouter,thai-tis620,nil>.
 [DB]  <font,layouter,thai-otf,nil>.
 [DB]  <font,layouter,gjr2-otf,nil>.
 [DB]  <font,layouter,tibt-mule,nil>.
 [DB]  <font,layouter,no-ctl,nil>.
 [DB]  <font,layouter,khmr-anlong,nil>.
 [DB]  <font,layouter,deva-otf,nil>.
 [DB]  <font,layouter,telu-otf,nil>.
 [DB]  <font,layouter,mymr-sil,nil>.
 [DB]  <font,layouter,mlm2-otf,nil>.
 [DB]  <font,layouter,thai-generic,nil>.
 [DB]  <font,layouter,dev2-otf,nil>.
 [DB]  <font,layouter,sinh-otf,nil>.
 [DB]  <font,layouter,taml-cdac,nil>.
 [DB]  <font,layouter,gur2-otf,nil>.
 [DB]  <font,layouter,tibt-otf,nil>.
 [DB]  <font,layouter,khmr-otf,nil>.
 [DB]  <font,layouter,tibt-mtib,nil>.
 [DB]  <font,layouter,beng-otf,nil>.
 [DB]  <font,layouter,combining,nil>.
 [DB]  <font,layouter,laoo-otf,nil>.
 [DB]  <font,layouter,arab-otf-no-gpos,nil>.
 [DB]  <font,layouter,hebr-ff,nil>.
 [DB]  <font,layouter,thaa-otf,nil>.
 [DB]  <font,layouter,cham-generic,nil>.

FWIW, when I change the font to DejaVu Sans (not Mono) and visit that
file, the display of all but one of the composed characters is correct
(as I previously mentioned), and the debugging output is exactly the
same as the above; and with the other LAOO-*.flt files under
/usr/share/m17n, on visiting that file when using variable pitch DejaVu
Sans (but not when using DejaVu Sans Mono), the debugging output
additionally contains these lines after the above output:

 [DB] <font,layouter,laoo-generic,nil> from /usr/share/m17n/LAOO-GENERIC.flt
 [FLT] (laoo-generic (dejavu sans)
 [FLT]   (SOURCE 0E94 0EB5)
 [FLT]   (STAGE 0 "CV" (0E94 0EB5)
 [FLT]     (SUBPART 0
 [FLT]      (COND
 [FLT]       (REGEX "^(Cs?[vV]?)(T)?" "CV" 2
 [FLT]        <0
 [FLT]        (SUBPART 1
 [FLT]         (COPY 0xE94)
 [FLT]         (COPY 0xEB5)) 2>))
 [FLT]      (COND)))
 [FLT]   (RESULT 00-01 (062A 640 0 0) (0644 0 0 0)))
 [FLT] (laoo-generic (dejavu sans)
 [FLT]   (SOURCE 0E82 0ECD)
 [FLT]   (STAGE 0 "CV" (0E82 0ECD)
 [FLT]     (SUBPART 0
 [FLT]      (COND
 [FLT]       (REGEX "^(Cs?[vV]?)(T)?" "CV" 2
 [FLT]        <0
 [FLT]        (SUBPART 1
 [FLT]         (COPY 0xE82)
 [FLT]         (COPY 0xECD)) 2>))
 [FLT]      (COND)))
 [FLT]   (RESULT 00-01 (0624 640 0 0) (0657 0 0 0)))
 [FLT] (laoo-generic (dejavu sans)
 [FLT]   (SOURCE 0EAB 0EC9)
 [FLT]   (STAGE 0 "CT" (0EAB 0EC9)
 [FLT]     (SUBPART 0
 [FLT]      (COND
 [FLT]       (REGEX "^(Cs?[vV]?)(T)?" "CT" 2
 [FLT]        <0
 [FLT]        (SUBPART 1
 [FLT]         (COPY 0xEAB))
 [FLT]        (SUBPART 2
 [FLT]         (CMB tr+5bl)
 [FLT]         (COPY 0xEC9)) 2>))
 [FLT]      (COND)))
 [FLT]   (RESULT 00-01 (063B 768 0 0) (0653 0 576 -48)))

Steve Berman