;; KNDA-OTF.flt -- Font Layout Table for Kannada OpenType fonts
;; Copyright (C) 2004, 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.

;;; <li> KNDA-OTF.flt
;;;
;;; For Kannada OpenType fonts to draw Kannada.
;;; Designed for Kedage-n.ttf <http://brahmi.sourceforge.net/downloads.html>

(font layouter knda-otf nil
      (font (nil nil unicode-bmp :otf=knda=rphf)))

(category
 ;; C: general consonant
 ;; R: RA
 ;; H: HALANT
 ;; u: MATRA (above)
 ;; b: MATRA (below)
 ;; p: MATRA (post)
 ;; t: MATRA (two-part)
 ;; T: MATRA (three-part)
 ;; a: vowel modifier (post)
 ;; V: independent vowel
 ;; N: ZWNJ (ZERO WIDTH NON-JOINER)
 ;; J: ZWJ (ZERO WIDTH JOINER)
 ;; E: ELSE
 ;;
 (0x200C	?N)			; ZWNJ
 (0x200D	?J)			; ZWJ
 (0x0964	?E)			; DANDA
 (0x0965	?E)			; DOUBLE DANDA
 (0x0C80 0x0CFF	?E)			; ELSE
 (0x0C82 0x0C83	?a)			; SIGN ANUSVARA, VISARGA
 (0x0C85 0x0C94	?V)			; LETTER A .. LETTER AU
 (0x0C95 0x0CB9	?C)			; LETTER KA .. LETTER HA
 (0x0CB0	?R)			; LETTER RA
 (0x0CBC	?n)			; SIGN NUKTA
 (0x0CBE 	?p)			; VOWEL SIGN AA (post)
 (0x0CBF	?u)			; VOWEL SIGN I (above)
 (0x0CC0	?t)			; VOWEL SIGN II (two-part)
 (0x0CC1 0x0CC4	?p)			; VOWEL SIGN U, UU, R, RR (post)
 (0x0CC6	?u)			; VOWEL SIGN E (above)
 (0x0CC7 0x0CCA	?t)			; VOWEL SIGN EE, AI, O (two-part)
 (0x0CCB	?T)			; VOWEL SIGN OO (three-part)
 (0x0CCC	?u)			; VOWEL SIGN AU (above)
 (0x0CCD	?H)			; SIGN VIRAMA (HALANT)
 (0x0CD5 0x0CD6	?l)			; LENGTH MARK (length post)
 (0x0CDE	?C)			; LETTER FA (LLLA)
 (0x0CE0 0x0CE1	?V)			; LETTER VOCALIC RR, LL
 (0x0CE2 0x0CE3	?b)			; VOWEL SIGN VOCALIC L, LL
 (0x0CFD	?Z)			; internal use
 (0x0CFE	?Y)			; internal use
 (0x0CFF	?X)			; internal use
 )

;; Step 1 : Syllable identification and Halant movement.
(generator
 (0
  (cond
   ;; A syllable containing a three-part vowel sign.
   ("([CR]J?n?(H[CR]n?)*)(T)(a)?"
    < | (1 move-base-Halant) (3 0x0CC6 0x0CC2 0x0CD5) (4 =) | >)

   ;; A syllable containing a two-part vowel sign.
   ("([CR]J?n?(H[CR]n?)*)(t)(a)?"
    < | (1 move-base-Halant) (3 two-part) (4 =) | >)

   ;; A syllable ending with vowel signs and/or a vowel modifier.
   ("([CR]J?n?(H[CR]n?)*)([ubpl]+a?|a)"
    < | (1 move-base-Halant) (3 = *) | >)

   ;; Forced Halant form.
   ("([CR]n?H)N"
    < | move-base-Halant | >)

   ;; A syllable without a vowel sign nor a vowel modifier.
   ("[CR]J?n?(H[CR]n?)*H?"
    < | move-base-Halant | >)

   ;; A syllable starting with an independent vowel.
   ("Va?"
    < | = * | > )

   ("." =))
  *)

 ;; Move Halant on the base consonant to the tail if the syllable ends
 ;; with a consonant.
 ;; A leading 0x0CFF means Halant movement.
 ;; A leading 0x0CFE means a syllable ending with a Halant.
 ;; A leading 0x0CFD means Halant & Reph movements.
 (move-base-Halant
  (cond
   (".*H$"
    0x0CFE = *)
   ("(RH)([CR]n?)$"
    0x0CFD (2 = *) (1 = =))
   ("(RH)([CR]n?)(H)(.*)"
    0x0CFD (2 = *) (4 = *) (3 =) (1 = =))
   ("(R)J(H)(.*)"
    0x0CFF (1 =) (3 = *) (2 =))
   ("(Cn?)(H)(.*)"
    0x0CFF (1 = *) (3 = *) (2 =))
   (".*"
    = *)))

 ;; Divide a two-part Matra into elements.
 (two-part
  (cond
   ((0x0CC0)	0x0CBF 0x0CD5)
   ((0x0CC7)	0x0CC6 0x0CD5)
   ((0x0CC8)	0x0CC6 0x0CD6)
   ((0x0CCA)	0x0CC6 0x0CC2)))
 )

;; Step 2 : Move Matra if applicable.
;; The base consonant in a Halant-ending syllable is changed into Halant form.
(generator
 (0
  (cond
   ;;  1       2        3   4   5   6   7   8
   (" Z([CR]n?)([CRnH]*)(RH)(u)?(b)?(p)?(l*)(a)? "
    | (1 = *) (4 =) (5 =) (6 =) (2 = *) (7 = *) (3 otf:knda=rphf) (8 =) |)
   ;;  1       2        3   4   5   6   7
   (" X([CR]n?)([CRnH]*)(u)?(b)?(p)?(l*)(a)? "
    | (1 = *) (3 =) (4 =) (5 =) (2 = *) (6 = *) (7 =) |)
   (" Y([CR]n?H)([^ ]*) "
    ;; Kedage-n.ttf lacks the haln feature, so "otf:knda=haln" does not work.
    | (1 otf:knda=~rphf,~blwf,*) (2 = *) |)
   ("." =))
  *))

;; Step 3 : Drive OTF tables.
(generator
 (0
  (cond
   (" ([^ ]*) "
    (1 otf:knda=~rphf,*))
   ("."
    [ otf:knda=+ ]))
  *))

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