From bb06adacb28740dc2efb6c1e8e4d4b3a6b94c27e Mon Sep 17 00:00:00 2001 From: ntakahas Date: Thu, 26 Jul 2007 09:10:24 +0000 Subject: [PATCH] Rewritten with new algorithm. --- FLT/MLYM-OTF.flt | 285 +++++++++++++++++++++++++++++------------------------- 1 file changed, 151 insertions(+), 134 deletions(-) diff --git a/FLT/MLYM-OTF.flt b/FLT/MLYM-OTF.flt index 8cbb821..419b0a2 100644 --- a/FLT/MLYM-OTF.flt +++ b/FLT/MLYM-OTF.flt @@ -26,180 +26,197 @@ ;;; For Malayalam OpenType fonts to draw the reformed Malayalam script. (font layouter mlym-otf nil - (font (nil nil unicode-bmp :otf=mlym=haln))) + (font (nil nil unicode-bmp :otf=mlym=blwf))) -;; The first stage is to extract a syllable and re-order characters. (category - ;; C: consonant (except for BPR) - ;; B: consonant that is the subject of "blws" feature - ;; P: consonant that is the subject of "pstf" feature + ;; C: consonant (except for R, B, and P) ;; R: consonant RA - ;; H: HALANT (VIRAMA) - ;; m: MATRA (Mpre) - ;; p: MATRA (Mpost) - ;; t: MATRA (two-part: Mpre+Mpost) - ;; A: vowel modifier (post) (ANUSVARA and VISARGA) + ;; B: consonant (below) + ;; P: consonant (post) + ;; H: HALANT + ;; m: vowel sign (pre) + ;; p: vowel sign (post) + ;; A: vowel modifier (post) ;; V: independent vowel ;; N: ZWNJ (ZERO WIDTH NON-JOINER) ;; J: ZWJ (ZERO WIDTH JOINER) - ;; E: else (all other independnt characters) - (0x0D00 0x0D7F ?E) ; else - (0x0D02 0x0D03 ?A) ; ANUSVARA & VISARGA - (0x0D05 0x0D14 ?V) ; independent vowel - (0x0D15 0x0D39 ?C) ; consonant - - ;; Accorind to www.microsoft.com/typography/otfntdev/indicot/appen.htm, - ;; these must be classified into 'B' category, but at least, it - ;; doesn't work with this font - ;; http://www.supersoftweb.com/THOOLIUC.TTF - ;;(0x0D1F ?B) ; TTA - ;;(0x0D23 ?B) ; NNA - ;;(0x0D26 ?B) ; DA - (0x0D2F ?P) ; YA - (0x0D30 ?R) ; RA - (0x0D32 ?B) ; LA - (0x0D35 ?P) ; VA - (0x0D3E 0x0D43 ?p) ; dependent vowel (Mpost) - (0x0D46 0x0D48 ?m) ; dependent vowel (Mpre) - (0x0D4A 0x0D4C ?t) ; dependent vowel (two-part) - (0x0D4D ?H) ; VIRAMA (HALANT) - (0x0D57 ?p) ; dependent vowel (Mpost) - (0x0D60 ?V) ; VOCALIC RR - (0x0D61 ?V) ; VOCALIC LL + ;; X: generic + ;; Z: internal use + (0x0D00 0x0D7F ?X) ; generic + (0x0D00 ?Z) ; internal use + (0x0D02 0x0D03 ?A) ; SIGN ANUSVARA .. VISARGA + (0x0D05 0x0D14 ?V) ; LETTER A .. LETTER AU + (0x0D15 0x0D39 ?C) ; LETTER KA .. LETTER HA + (0x0D2F ?P) ; LETTER YA + (0x0D30 ?R) ; LETTER RA + (0x0D32 ?B) ; LETTER LA + (0x0D35 ?P) ; LETTER VA + (0x0D3E 0x0D43 ?p) ; VOWEL SIGN AA .. VOCALIC R + (0x0D46 0x0D48 ?m) ; VOWEL SIGN E .. AI + (0x0D4D ?H) ; SIGN VIRAMA + (0x0D57 ?p) ; AU LENGTH MARK + (0x0D60 0x0D61 ?V) ; LETTER VOCALIC RR .. VOCALIC LL + (0x0964 0x0965 ?X) ; DANDA .. DOUBLE DANDA (0x200C ?N) ; ZWNJ (0x200D ?J) ; ZWJ - (0x0D7D ?x) ; marker inserted before base-C - (0x0D7E ?y) ; marker inserted after base-C - (0x0D7F ?z) ; marker inserted before last Ra ) -;; The 1st stage is to extract a syllable while moving a Halant -;; following Cbase to the tail and partitioning two-part matras into -;; parts. +;; Decompose two-part vowels. (generator (0 (cond - ;; If [CR]H is followed by ZWNJ/ZWJ, move ZWNJ/ZWJ) to the head so - ;; that the later stages find it quickly. - ("([CBPR]H)([NJ])" - < | (2 =) (1 = =) | >) - - ;; A syllable starting with a consonant and ending with a vowel - ;; and/or a vowel modifier. - ("(([CBPR]H)*[CBPR])([pmt]A?|A)" - < | (1 move-halant) (3 partition = =) | >) - - ;; A syllable starting with a consonant and ending without a vowel - ;; nor a vowel modifier. - ("(([CBPR]H)*[CBPR])(H)?" - < | (1 move-halant) (3 =) | >) - - ;; A syllable starting with an independent vowel. + ((0x0D4A) + 0x0D46 0x0D3E) + ((0x0D4B) + 0x0D47 0x0D3E) + ((0x0D4C) + 0x0D46 0x0D57) + ("." =)) + *)) + +;; Syllable identification and reordering. +;; Put the mark 0x0D00 before the first pre-base consonant and after +;; the base consonant. +(generator + (0 + (cond + ;; A syllable with a left vowel sign. + ;;1 2 3 4 + ("([CRBP](H[CRBP])*)(m)(p?A?)" + < | (3 =) (1 get-rh) 0x0D00 (1 move-h) (4 = *) | >) + + ;; A syllable with a right vowel sign and/or a vowel modifier. + ;;1 2 3 + ("([CRBP](H[CRBP])*)(pA?|A)" + < | (1 get-rh) 0x0D00 (1 move-h) (3 = *) | >) + + ;; Explicit Halant / forced chillu form is cut off from the preceders. + ("(([CRBP]H)*)([CRBP]H[NJ])" + (1 cut-off) (3 < | = * | >)) + + ;; A syllable with no vowel signs/modifiers. + ("([CRBP](H[CRBP])*H?)" + < | (1 get-rh) 0x0D00 (1 move-h) | >) + + ;; Starting with an independent vowel. ("(VA?)" < | (1 = *) | >) - ;; Other independent character. ("." =)) *) - ;; Move Halant to the tail if necessary. Insert 0x0D7D before Cbase, - ;; 0x0D7E after Cbase, 0x0D7F before the tailing RH (if any). They - ;; work as markers in the following stages. - (move-halant + ;; Extract RH that will be moved to the left. + (get-rh + (cond + (".+HR$" + 0x0D30 0x0D4D))) + + ;; Move the halant after the base consonant to the end. + ;; Fill the resulting gap with 0x0D00. + ;; Remove final RH if any. + (move-h (cond - ;; In the first two cases, we don't have to move Halant. - ("[BPR]$" ; Single consonant. - 0x0D7D 0x0D7E =) - ("(([CBPR]H)*)(C)$" ; Cbase is at tail. - (1 = *) 0x0D7D (3 =) 0x0D7E) - ;; In the following cases, we must move Halant to the tail. - ("(([CBPR]H)*)([C])H(([BR]H)*)(R)$" ; Cbase is at head or middle. - (1 = *) 0x0D7D (3 =) 0x0D7E (4 = *) 0x0D7F 0x0D30 0x0D4D) - ("(([CBPR]H)*)([C])H(([BR]H)*[BP])$" ; Cbase is at head or middle. - (1 = *) 0x0D7D (3 =) 0x0D7E (4 = *) 0x0D4D) - ("(RH)?(.)H(.*)$" ; No Cbase, move the first - ; Halant to the tail. - (1 = *) 0x0D7D (2 = ) 0x0D7E (3 = *) 0x0D4D))) - - ;; Partition two-part matras into parts. - (partition + ;; There is a C and the syllable ends with an R. Remove final RH. + ("([CRBPH]*C)H([RBPH]*)R$" + (1 = *) 0x0D00 (2 = *)) + + ;; The syllable ends other than R. Move H. + ("([CRBPH]*C)(H)([RBPH]+)$" + (1 = *) 0x0D00 (3 = *) (2 =)) + + ;; No C and end with R. The first consonant will be the base. Remove RH. + ("([RBP])H([RBPH]*)R$" + (1 =) 0x0D00 (2 = *)) + + ;; No C and not end with R. Move H. + ("([RBP])(H)([RBPH]+)$" + (1 =) 0x0D00 (3 = *) (2 =)) + + ;; Otherwise, no need to move H. + (".+" + = * 0x0D00))) + + ;; If there are some letters make them a separate syllable. + (cut-off (cond - ((0x0D4A) 0x0D46 0x0D3E) - ((0x0D4B) 0x0D47 0x0D3E) - ;; Unicode suggests this partitioning: - ((0x0D4C) 0x0D46 0x0D57) - ;; but it is questionable. Perhaps, this substitution is better. - ;; ((0x0D4C) 0x0D57) - ))) - -;; The 2nd stage is to apply GSUB for prebase part. + (".+" + < | = * | >))) + ) + +;; Apply GSUB features. +;; According to Microsoft Typography +;; +;; 'chillu' are generated with the 'haln' feature. However, some +;; fonts generate them with 'half'. (generator (0 (cond - ;; Originally [CBPR]H is followed by ZWNJ. Apply no feature (just - ;; cmap). - (" N([^ ]*) " - (1 otf:mlym=+)) - - ;; Originally [CBPR]H is followed by ZWJ. Apply only GSUB haln - ;; feature. - (" J([^ ]*) " - (1 otf:mlym=haln+)) - - ;; Syllable starting with a consonant should match this pattern. - (" ([^ y]*)y([^ z]*)(z..)?([^ ]*) " - | - (1 otf:mlym=~blwf,~pstf,~blws,~psts,*+) ; Prebase part. - 0x0D7E ; Preserve this marker. - (2 = *) ; Postbase part. - (3 = *) ; Optional tailing RH. - (4 = *) ; Optional Mpost. - |) - - ;; A syllable starting with an independent vowel. - (" ([^ ]*) " - (1 otf:mlym+)) - - ;; Any other independent character. Apply no feature (just cmap). - ("." - [ otf:mlym=+ ] )) + ;; Ordinary syllable. We must avoid applying 'blwf' and 'pstf' to + ;; the first consonant. Also 'haln' and 'half' must be avoided + ;; because chillu does not appear at the beginning of a word. Thus + ;; we apply only 'akhn' here and postpone applying other features + ;; to the next stage. + ;; 1 2 3 4 5 + (" (m?(RH)?Z)([CRBPH]+)(Z)([RBPHpA]*) " + | (1 = *) (3 otf:mlym=akhn+) (4 =) + (5 otf:mlym=blwf,pstf+) |) + + ;; Explicit Halant. + (" [CRBP]HN " + = *) + + ;; Forced chillu form. + (" ([CRBP]H)(J) " + | (1 otf:mlym=haln,half+) (2 =) |) + + ;; Sequence that was cut off from a forced form. Again we apply + ;; only 'akhn' here. + (" ([CRBPH]+) " + | (1 otf:mlym=akhn+) |) + + ("." =)) *)) -;; The 3rd stage is to move Mpre (if any) and tailing RH (if any) -;; forward to just before the base consonant. +;; Apply postoponed GSUB features to ordinary syllables. (generator (0 (cond - (" ([^x]*)(.)xy([^ zm]*)(z(..))?(m)?([^ ]*) " - | (1 = *) (4 (5 otf:mlym=pstf+)) (6 =) 0x0D7D (2 =) (3 = *) (7 = *) |) - (" ([^x]*)x(.)y([^ zm]*)(z(..))?(m)?([^ ]*) " - | (1 = *) (4 (5 otf:mlym=pstf+)) (6 =) 0x0D7D (2 =) (3 = *) (7 = *) |) - (" xy([^ m]*)(m)?([^ ]*) " - | (2 =) 0x0D7D (1 = *) (3 = *) |) - ("[NJ]") - ("." - = )) + ;; Ordinary syllable. + ;; 1 2 3 4 + (" (m?(RH)?Z[^Z])([^Z]*)(Z[^ ]*) " + | (1 = *) (3 otf:mlym=blwf,half,pstf,haln+) (4 = *) |) + + ;; Explicit Halant / Forced chillu must not change to others. + (" (.+)[NJ] " + | (1 = *) |) + + ;; Cut off sequence. + (" ([^ ])([^ ]*) " + | (1 =) (2 otf:mlym=blwf,half,pstf,haln+) |) + + ("." =)) *)) -;; The 4th stage is to apply GSUB to postbase part. +;; Second reordering. If there are glyphs before the base, move left +;; vowel sign and RH to the left of the base. (generator (0 (cond - (" ([^x]*)x(.H) " - | (1 = *) (2 otf:mlym=haln) |) - (" ([^x]*)x([^ ]*) " - | (1 = *) (2 otf:mlym=~akhn,~haln,blwf,pstf,vatu,*+) |) + ;; 1 2 3 4 5 + (" (m)?(RH)?Z([^Z]*)([^Z])Z([^ ]*) " + | (3 = *) (1 =) (2 otf:mlym=pstf+) (4 =) (5 = *) |) + ("." =)) *)) - - -;; The 5th (last) stage is to apply GPOS features. +;; Apply substitutions and GPOS features. (generator (0 (cond - (" ([^ ]*) " (1 otf:mlym=)) - ("." =)) + (" ([^ ]+) " + (1 otf:mlym=pres,abvs,blws,psts)) + ("." + [ otf:mlym=+ ])) *)) ;; Local Variables: -- 1.7.10.4