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typesetting/pitfall/fontkit/opentype.rkt

93 lines
3.0 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 (mhash 'type '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 uint16be #;(+Pointer uint16be Script (mhash 'type 'parent)))))
(define-subclass Array (ScriptRecordArray)
(define/override (decode stream ctx)
(define val (super decode stream ctx))
(report (· this _len))
val))
(define ScriptList (+ScriptRecordArray ScriptRecord uint16be))
(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)))))
(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)))))