Re: otf ligature rendering support?

[handa@gnu.org (K. Handa)]

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In article <m86d9m$1ii$1@ger.gmane.org>, Yuri D'Elia <wavexx@thregr.org> writes:

> I'm not fully aware of how much otf is supported in emacs, but I found a
> good reason to want ligatures in a monospaced font:

> http://www.fsd.it/fonts/pragmatapro/PragmataPro_Haskell_liga.png

> PragmataPro supports ligatures for a good set of common operators. This
> makes it much less troublesome than "prettify-symbols-mode" since
> indentation/spacing is not changed.

> How would I enable the proper GSUB feature in emacs? Are ligatures
> supported at all?

Currently, Emacs can not control which OTF features to
apply.  Emacs leaves it to font drivers on eash platform.  I
actually tried to give Emacs such facility, and src/font.c
contains not-yet-finished code within "#if 0" and "#endif".

I want to finish the code, but I'm not sure I can work on it
soon.

> I can specify otf parameters in `font-spec', but the following:

> (set-fontset-font nil 'latin
> 		  (font-spec :family "PragmataPro"
> 			     :otf '(latn nil (liga))))

> Doesn't really show any ligatures (or any other otf feature).

The above just tells Emacs to select such an OTF font that
has `liga' GPOS feature for `latn' script.

By the way, if you are running Emacs on X with libm17n-flt
and libotf libraries, you can override the default behavior
of those libraries by putting the attached two files under
~/.m17n.d/.  It assumes that the family name of PragmataPro
font is "PragmataPro".  If that is not the case, please
replace "PragmataPro" in generic.fst with a proper family
name.

---
K. Handa
handa@gnu.org


[-- Attachment #2: generic.fst --]
[-- Type: application/octet-stream, Size: 3825 bytes --]

;; generic.fst -- Fontset mainly using generic font specs.
;; Copyright (C) 2005, 2006, 2007, 2010  AIST (H15PRO112)
;; See the end for copying conditions.

;;; <li> generic.fst
;;;
;;; Fontset mainly using generic font specifications.  See the
;;; documentation of the fontset "default" for the information about
;;; each font.

(latin
 (vi
  ((nil PragmataPro unicode-bmp) combining)
  ((nil nil unicode-bmp :lang=vi)))
 (nil
  ((nil PragmataPro unicode-bmp) combining)
  ((nil nil unicode-bmp :script=latin))))
(hebrew
 (nil
  ((nil nil unicode-bmp :otf=hebr) hebr-otf)
  ((nil nil unicode-bmp :script=hebrew))))
(arabic
 (nil
  ((nil nil unicode-bmp :otf=arab=init,medi,fina,liga+mark) arab-otf)
  ((nil nil unicode-bmp :otf=arab=init,medi,fina,liga+~mark) arab-otf-no-gpos)
  ((nil nil unicode-bmp :script=arabic) arab)))
(syriac
 (nil
  ((nil nil unicode-bmp :otf=syrc) syrc-otf)))
(thaana
 (nil
  ((nil nil unicode-bmp :otf=thaa) thaa-otf)
  ((nil nil unicode-bmp :script=thaana))))
(devanagari
 (nil
  ((nil nil unicode-bmp :otf=dev2) dev2-otf)
  ((nil nil unicode-bmp :otf=deva) deva-otf)))
(bengali
 (nil
  ((nil nil unicode-bmp :otf=bng2) bng2-otf)
  ((nil nil unicode-bmp :otf=beng) beng-otf)))
(gurmukhi
 (nil
  ((nil nil unicode-bmp :otf=gur2) gur2-otf)
  ((nil nil unicode-bmp :otf=guru) guru-otf)))
(gujarati
 (nil
  ((nil nil unicode-bmp :otf=gjr2) gjr2-otf)
  ((nil nil unicode-bmp :otf=gujr) gujr-otf)))
(oriya
 (nil
  ((nil nil unicode-bmp :otf=ory2) ory2-otf)
  ((nil nil unicode-bmp :otf=orya) orya-otf)))
(tamil
 (nil
  ((nil nil unicode-bmp :otf=tml2) tml2-otf)
  ((nil nil unicode-bmp :otf=taml) taml-otf)))
(telugu
 (nil
  ((nil nil unicode-bmp :otf=tel2) tel2-otf)
  ((nil nil unicode-bmp :otf=telu) telu-otf)))
(kannada
 (nil
  ((nil nil unicode-bmp :otf=knd2) knd2-otf)
  ((nil nil unicode-bmp :otf=knda) knda-otf)))
(malayalam
 (nil
  ((nil nil unicode-bmp :otf=mlm2) mlm2-otf)
  ((nil nil unicode-bmp :otf=mlym) mlym-otf)))
(sinhala
 (nil
  ((nil nil unicode-bmp :otf=sinh) sinh-otf)))
(tibetan
 (nil
  ((nil nil unicode-bmp :otf=tibt) tibt-otf)))
(thai
 (nil
  ((nil nil unicode-bmp :otf=thai) thai-otf)
  ((nil nil unicode-bmp :script=thai) thai-generic)))
(lao
 (nil
  ((nil nil unicode-bmp :otf=laoo) laoo-otf)
  ((nil nil unicode-bmp :script=lao) laoo-generic)))
(myanmar
 (nil
  ((nil padauk unicode-bmp) mymr-sil)))
(khmer
 (nil
  ((nil nil unicode-bmp :otf=khmr) khmr-otf)))
(han
 (zh
  ((nil nil unicode-bmp :lang=zh)))
 (ja
  ((nil nil unicode-bmp :lang=ja)))
 (ko
  ((nil nil unicode-bmp :lang=ko))))
(hiragana
 (nil
  ((nil nil unicode-bmp :lang=ja))))
(katakana
 (nil
  ((nil nil unicode-bmp :lang=ja))))
(hangul
 (nil
  ((nil nil unicode-bmp :lang=ko))))
(cham
 (nil
  ((nil nil unicode-bmp :script=cham) cham-generic)))
(nil
 ((nil nil unicode-bmp)))

;; Copyright (C) 2003, 2004, 2007, 2010
;;   National Institute of Advanced Industrial Science and Technology (AIST)
;;   Registration Number H15PRO112

;; This file is part of the m17n database; a sub-part of the m17n
;; library.

;; The m17n library is free software; you can redistribute it and/or
;; modify it under the terms of the GNU Lesser General Public License
;; as published by the Free Software Foundation; either version 2.1 of
;; the License, or (at your option) any later version.

;; The m17n library is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; Lesser General Public License for more details.

;; You should have received a copy of the GNU Lesser General Public
;; License along with the m17n library; if not, write to the Free
;; Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;; Local Variables:
;; mode: lisp
;; End:

[-- Attachment #3: COMBINING.flt --]
[-- Type: application/octet-stream, Size: 2131 bytes --]

;; COMBINING.flt -- Font Layout Table for combining diacritical marks
;; Copyright (C) 2007  AIST (H15PRO112)
;; See the end for copying conditions.

(font layouter combining nil)

;;; <li> COMBINING.flt
;;;
;;; For combining diacritical marsk (U+0300..U+036F).

(category
 ;; The contents is build up by the m17n-lib.
 )

(generator
 (0
  (cond
   ("(u)([a-t]+)"
    (cond
     ((font-facility :otf=DFLT=liga) < :otf=DFLT=liga >)
     ((font-facility :otf=DFLT+mark) < :otf=DFLT+mark,mkmk >)
     (".*"
      <	=				; combining class
      (cond ("a" Bc.Bc =)		; < 200
	    ("b" bl.tc =)		; 200
	    ("c" bc.tc =)		; 202
	    ("d" br.tc =)		; 204
	    ("e" Bl.Br =)		; 208
	    ("f" Br.Bl =)		; 210
	    ("g" tl.bc =)		; 212
	    ("h" tc.bc =)		; 214
	    ("i" tr.bc =)		; 216
	    ("j" bl.tc =)		; 218
	    ("k" bc-tc =)		; 220
	    ("l" br-tc =)		; 222
	    ("m" Bl.Br =)		; 224
	    ("n" Br.Bl =)		; 226
	    ("o" tl+bc =)		; 228
	    ("p" tc+bc =)		; 230
	    ("q" tr+bc =)		; 232
	    ("r" br-tr =)		; 233
	    ("s" tr+br =)		; 234
	    ("t" bc-tc =))		; 240
      * >)))
   ("[a-t]" [ = ])
   ("." =))
  *))

;; Copyright (C) 2007
;;   National Institute of Advanced Industrial Science and Technology (AIST)
;;   Registration Number H15PRO112

;; This file is part of the m17n database; a sub-part of the m17n
;; library.

;; The m17n library is free software; you can redistribute it and/or
;; modify it under the terms of the GNU Lesser General Public License
;; as published by the Free Software Foundation; either version 2.1 of
;; the License, or (at your option) any later version.

;; The m17n library is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; Lesser General Public License for more details.

;; You should have received a copy of the GNU Lesser General Public
;; License along with the m17n library; if not, write to the Free
;; Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;; Local Variables:
;; mode: emacs-lisp
;; End: