Developing OpenType Fonts for Bangla Script [ Microsoft Volt & Fontlab ]

 Character reordering Classes for Bangla:

Table 2

Characters                                                                               Reorder Class
U+09B0 - র ,  U+09F0 - ৰ  (reph)                                              AfterSubscript
U+09BF- ি , U+09C7-ে, U+09C8-ৈ                                       BeforeHalf
U+09C1- ু , U+09C2-ূ,  U+09C3-ৃ,                                         AfterSubscript U+09C4-ৄ, U+09E2-ৢ, U+09E3-ৡ, U+09F5-ৣ
U+09BE-া, U+09C0-ী, U+09D7-ৗ                                         AfterPostscript
U+0981-  ঁ,                                                                                 AfterPostscript Invalid Combining Marks U+200C    ‌   [  ZWNJ ]            Zero width non-joiner   U+200D      ‍ [ ZWJ ]              Zero width joiner  U+25CC                                Dotted Circle OpenType features used for Bengali scripts, applied in the following order: Feature Feature function Layout operation Localized forms: locl Localization form substitution GSUB Basic shaping forms: nukt Nukta form substitution GSUB akhn Akhand ligature substitution GSUB rphf Reph form substitution GSUB blwf Below-base form substitution GSUB half Half-form substitution GSUB pstf Post-base form substitution GSUB vatu Vattu variants GSUB cjct Conjunct form substitution GSUB Mandatory presentation forms: init Initial form GSUB pres Pre-base substitution GSUB abvs Above-base substitution GSUB blws Below-base substitution GSUB psts Post-base substitution GSUB haln Halant form substitution GSUB Discretionary presentation forms: calt Contextual alternates GSUB Positioning features: kern Kerning GPOS dist Distances GPOS abvm Above-base mark positioning GPOS blwm Below-base mark positioning GPOS [GSUB = glyph substitution, GPOS = glyph positioning] Localized forms Feature Tag: "locl" - OpenType language system tags Nukta form substitution Feature Tag:   "nukt"    Microsoft Volt:   Fontlab 5/6:- feature nukt { # Nukta Forms sub u09AC u09BC by u09B0; sub u09A1 u09BC by u09DC; sub u09A2 u09BC by u09DD; sub u09AF u09BC by u09DF; #> feature #< feature } nukt; Akhand Feature Tag: "akhn" Fontlab 5/6:- feature akhn { # Akhand sub u0995 u09CD u09B7 by u0995_u09CD_u09B7; sub u099C u09CD u099E by u099C_u09CD_u099E; #> feature #< feature } akhn;