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typesetting/pitfall/fontkit/opentype.rkt

127 lines
4.2 KiB
Racket

#lang fontkit/racket
(require restructure)
(provide (all-defined-out))
;;########################
;; Scripts and Languages #
;;########################
(define LangSysTable (+Struct
(dictify 'reserved uint16be
'reqFeatureIndex uint16be
'featureCount uint16be
'featureIndexes (+Array uint16be 'featureCount))))
(define LangSysRecord (+Struct
(dictify 'tag (+String 4)
'langSys (+Pointer uint16be LangSysTable 'parent))))
(define Script (+Struct
(dictify 'defaultLangSys (+Pointer uint16be LangSysTable)
'count uint16be
'langSysRecords (+Array LangSysRecord 'count))))
(define-subclass Struct (ScriptRecord-Struct))
(define ScriptRecord (+ScriptRecord-Struct
(dictify 'tag (+String 4)
'script (+Pointer uint16be Script 'parent))))
(define ScriptList (+Array ScriptRecord uint16be))
;;#######################
;; Features and Lookups #
;;#######################
(define Feature (+Struct (dictify
'featureParams uint16be ; pointer
'lookupCount uint16be
'lookupListIndexes (+Array uint16be 'lookupCount))))
(define FeatureRecord (+Struct (dictify
'tag (+String 4)
'feature (+Pointer uint16be Feature 'parent))))
(define FeatureList (+Array FeatureRecord uint16be))
(define LookupFlags (+Bitfield uint16be '(rightToLeft ignoreBaseGlyphs ignoreLigatures ignoreMarks useMarkFilteringSet #f markAttachmentType)))
(define (LookupList SubTable)
(define Lookup (+Struct
(dictify
'lookupType uint16be
'flags LookupFlags
'subTableCount uint16be
'subTables (+Array (+Pointer uint16be SubTable) 'subTableCount)
;'subTables (+Array uint16be 'subTableCount)
'markFilteringSet uint16be)))
(+Array (+Pointer uint16be Lookup) uint16be))
;;#############################################
;; Contextual Substitution/Positioning Tables #
;;#############################################
(define LookupRecord (+Struct
(dictify
'sequenceIndex uint16be
'lookupListIndex uint16be)))
(define Context
(+VersionedStruct
uint16be
(dictify
;; Simple context
1 (dictify
'coverage uint16be ; pointer
'ruleSetCount uint16be
'ruleSets (+Array uint16be 'ruleSetCount)) ; pointer
;; Class-based context
2 (dictify
'coverage uint16be ; pointer
'classDef uint16be ; pointer
'classSetCnt uint16be
'classSet (+Array uint16be 'classSetCnt)) ; pointer
3 (dictify
'glyphCount uint16be
'lookupCount uint16be
'coverages (+Array uint16be 'glyphCount) ; pointer
'lookupRecords (+Array LookupRecord 'lookupCount)))))
;;######################################################
;; Chaining Contextual Substitution/Positioning Tables #
;;######################################################
(define ChainingContext
(+VersionedStruct
uint16be
(dictify
;; Simple context glyph substitution
1 (dictify
'coverage uint16be ; pointer
'chainCount uint16be
'chainRuelSets (+Array uint16be 'chainCount)) ; pointer
;; Class-based chaining context
2 (dictify
'coverage uint16be ; pointer
'backtrackClassDef uint16be ; pointer
'inputClassDef uint16be ; pointer
'lookaheadClassDef uint16be ; pointer
'chainCount uint16be
'chainClassSet (+Array uint16be 'chainCount)) ; pointer
;; Coverage-based chaining context
3 (dictify
'backtrackGlyphCount uint16be
'backtrackCoverage (+Array uint16be 'backtrackGlyphCount) ; pointer
'inputGlyphCount uint16be
'inputCoverage (+Array uint16be 'inputGlyphCount) ; pointer
'lookaheadGlyphCount uint16be
'lookaheadCoverage (+Array uint16be 'lookaheadGlyphCount) ; pointer
'lookupCount uint16be
'lookupRecords (+Array LookupRecord 'lookupCount)))))