You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
84 lines
3.3 KiB
Racket
84 lines
3.3 KiB
Racket
#lang fontkit/racket
|
|
(require "gsub-processor.rkt" "gpos-processor.rkt" "glyphinfo.rkt" (prefix-in Shapers- "shapers.rkt") "shaping-plan.rkt")
|
|
(provide (all-defined-out))
|
|
|
|
#|
|
|
https://github.com/mbutterick/fontkit/blob/master/src/opentype/OTLayoutEngine.js
|
|
|#
|
|
|
|
(define-subclass object% (OTLayoutEngine font)
|
|
(field [glyphInfos #f]
|
|
[shaper #f]
|
|
[plan #f]
|
|
[GSUBProcessor #f]
|
|
[GPOSProcessor #f])
|
|
|
|
#;(report/file 'starting-ot-layout-engine)
|
|
(when (· font has-gsub-table?)
|
|
(set-field! GSUBProcessor this (+GSUBProcessor font (or (· font GSUB) (error 'no-gsub-table)))))
|
|
|
|
|
|
(when (· font has-gpos-table?)
|
|
(set-field! GPOSProcessor this (+GPOSProcessor font (or (· font GPOS) (error 'no-gpos-table)))))
|
|
|
|
|
|
(define/public (setup glyphs features script language)
|
|
;; Map glyphs to GlyphInfo objects so data can be passed between
|
|
;; GSUB and GPOS without mutating the real (shared) Glyph objects.
|
|
(set! glyphInfos (map (λ (glyph) (+GlyphInfo (· this font) (· glyph id) (· glyph codePoints))) glyphs))
|
|
|
|
;; Choose a shaper based on the script, and setup a shaping plan.
|
|
;; This determines which features to apply to which glyphs.
|
|
(set! shaper (Shapers-choose script))
|
|
(set! plan (+ShapingPlan (· this font) script language))
|
|
#;(report/file shaper)
|
|
(send (make-object shaper) plan (· this plan) (· this glyphInfos) features))
|
|
|
|
(define/public (substitute glyphs . _)
|
|
(cond
|
|
[(· this GSUBProcessor)
|
|
#;(report/file (· this glyphInfos))
|
|
(define new-glyphinfos
|
|
(send (· this plan) process (· this GSUBProcessor) (· this glyphInfos)))
|
|
(set! glyphInfos new-glyphinfos) ; update OTLayoutEngine state for positioning pass
|
|
#;(report/file new-glyphinfos)
|
|
;; Map glyph infos back to normal Glyph objects
|
|
#;(report/file (for/list ([glyphInfo (in-list new-glyphinfos)])
|
|
(send (· this font) getGlyph (· glyphInfo id) (· glyphInfo codePoints))))
|
|
(for/list ([glyphInfo (in-list new-glyphinfos)])
|
|
(send (· this font) getGlyph (· glyphInfo id) (· glyphInfo codePoints)))]
|
|
[else glyphs]))
|
|
|
|
(define/public (position glyphs positions . _)
|
|
#;(report*/file glyphs positions shaper)
|
|
(define static-shaper (make-object shaper))
|
|
(when (eq? (· static-shaper zeroMarkWidths) 'BEFORE_GPOS)
|
|
(zeroMarkAdvances positions))
|
|
|
|
(when GPOSProcessor
|
|
#;(report/file GPOSProcessor)
|
|
(send (· this plan) process GPOSProcessor glyphInfos positions))
|
|
|
|
(when (eq? (· static-shaper zeroMarkWidths) 'AFTER_GPOS)
|
|
(zeroMarkAdvances positions))
|
|
|
|
;; Reverse the glyphs and positions if the script is right-to-left
|
|
(when (eq? (· this plan direction) 'rtl)
|
|
(set! glyphs (reverse glyphs))
|
|
(set! positions (reverse positions)))
|
|
|
|
#;(report/file (and GPOSProcessor (· GPOSProcessor features)))
|
|
(and GPOSProcessor (· GPOSProcessor features)))
|
|
|
|
|
|
(define/public (zeroMarkAdvances positions)
|
|
(set! positions
|
|
(for/list ([glyphInfo (in-list glyphInfos)]
|
|
[position (in-list positions)])
|
|
(when (· glyphInfo isMark)
|
|
(dict-set*! position
|
|
'xAdvance 0
|
|
'yAdvance 0))
|
|
position)))
|
|
|
|
) |