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structify glyph

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main
Matthew Butterick 6 years ago
parent 6a7826c8b1
commit 5125ac1073
4 changed files with 176 additions and 162 deletions
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14
fontland/fontland/font.rkt
Unescape Escape View File

@ -244,13 +244,13 @@ https://github.com/mbutterick/fontkit/blob/master/src/TTFFont.js
;; Returns a glyph object for the given glyph id.
;; You can pass the array of code points this glyph represents for
;; your use later, and it will be stored in the glyph object.
(define/contract (getGlyph this glyph [characters null])
((index?) ((listof index?)) . ->*m . (is-a?/c Glyph))
(define (getGlyph this glyph [characters null])
#;((index?) ((listof index?)) . ->*m . glyph?)
;; no CFF
#;(make-object (if (· this has-cff-table?)
CFFGlyph
TTFGlyph) glyph characters this)
(make-object TTFGlyph glyph characters this))
(+ttf-glyph glyph characters this))
(define current-layout-caching (make-parameter #false))
@ -340,8 +340,8 @@ https://github.com/mbutterick/fontkit/blob/master/src/TTFFont.js
;; This is only a one-to-one mapping from characters to glyphs.
;; For most uses, you should use font.layout (described below), which
;; provides a much more advanced mapping supporting AAT and OpenType shaping.
(define/contract (glyphsForString this string)
(string? . ->m . (listof (is-a?/c Glyph)))
(define (glyphsForString this string)
#;(string? . ->m . (listof glyph?))
;; todo: make this handle UTF-16 with surrogate bytes
;; for now, just use UTF-8
@ -352,8 +352,8 @@ https://github.com/mbutterick/fontkit/blob/master/src/TTFFont.js
;; Maps a single unicode code point to a Glyph object.
;; Does not perform any advanced substitutions (there is no context to do so).
(define/contract (glyphForCodePoint this codePoint)
(index? . ->m . Glyph?)
(define (glyphForCodePoint this codePoint)
#;(index? . ->m . glyph?)
(define glyph-idx (FT_Get_Char_Index (· this ft-face) codePoint))
(send this getGlyph glyph-idx (list codePoint)))

310
fontland/fontland/glyph.rkt
Unescape Escape View File

@ -31,60 +31,64 @@ approximates
https://github.com/mbutterick/fontkit/blob/master/src/glyph/Glyph.js
|#
(define-subclass object% (Glyph id codePoints font)
(field [_font font]
[isMark (andmap is-mark? codePoints)]
[isLigature (> (length codePoints) 1)]
[_metrics #f])
(as-methods
_getPath
_getCBox
_getBBox
_getTableMetrics
advanceWidth
_getMetrics))
(define-stub-stop _getPath)
(define-stub-stop _getCBox)
(define-stub-stop _getBBox)
(define-stub-stop _getTableMetrics)
(define/contract (advanceWidth this)
(->m number?)
(hash-ref (_getMetrics this) 'advanceWidth))
(define/contract (_getMetrics this)
(->m hash?)
(unless (· this _metrics)
(define face (· this _font ft-face))
(FT_Load_Glyph face (· this id) FT_LOAD_NO_RECURSE)
#;(define-subclass object% (Glyph id codePoints font)
(field [_font font]
[isMark (andmap is-mark? codePoints)]
[isLigature (> (length codePoints) 1)]
[_metrics #f])
(as-methods
advanceWidth
_getMetrics))
(struct glyph (id codePoints font _font isMark isLigature _metrics) #:transparent #:mutable)
(define (+glyph id codePoints font
[_font font]
[isMark (andmap is-mark? codePoints)]
[isLigature (> (length codePoints) 1)]
[_metrics #f]
#:constructor [constructor glyph])
(constructor id codePoints font _font isMark isLigature _metrics))
#;(define-stub-stop _getPath)
#;(define-stub-stop _getCBox)
#;(define-stub-stop _getBBox)
#;(define-stub-stop _getTableMetrics)
(define (glyph-advance-width g)
(hash-ref (_getMetrics g) 'advanceWidth))
(define (_getMetrics g)
(unless (glyph-_metrics g)
(define face (· (glyph-_font g) ft-face))
(FT_Load_Glyph face (glyph-id g) FT_LOAD_NO_RECURSE)
(define glyph (FT_FaceRec-glyph face))
(define glyph-metrics (FT_GlyphSlotRec-metrics glyph))
(set-field! _metrics this (mhash))
(hash-set*! (· this _metrics)
(set-glyph-_metrics! g (mhash))
(hash-set*! (glyph-_metrics g)
'advanceWidth (FT_Glyph_Metrics-horiAdvance glyph-metrics)
'leftBearing (FT_Glyph_Metrics-horiBearingX glyph-metrics)))
(· this _metrics))
(glyph-_metrics g))
#|
approximates
https://github.com/mbutterick/fontkit/blob/master/src/glyph/CFFGlyph.js
|#
(define-subclass Glyph (CFFGlyph)
(error 'cff-glyph-unimplemented)
#;(define-subclass Glyph (CFFGlyph)
(error 'cff-glyph-unimplemented)
#;(define/override (_getName this)
(->m any/c)
(if (send (· this _font) _getTable 'CFF2)
(super _getName)
(send (send (· this _font) _getTable 'CFF_) getGlyphName (· this id))))
(as-methods
#;_getName
#;bias
#;_getPath))
#;(define/override (_getName this)
(->m any/c)
(if (send (· this _font) _getTable 'CFF2)
(super _getName)
(send (send (· this _font) _getTable 'CFF_) getGlyphName (· this id))))
(as-methods
#;_getName
#;bias
#;_getPath))
@ -146,117 +150,125 @@ https://github.com/mbutterick/fontkit/blob/master/src/glyph/TTFGlyph.js
[scale10 0]))
;; Represents a TrueType glyph.
(define-subclass Glyph (TTFGlyph)
(inherit-field _font id)
#;(define-subclass Glyph (TTFGlyph)
(inherit-field _font id))
;; Parses just the glyph header and returns the bounding box
(define/override (_getCBox internal)
(struct ttf-glyph glyph () #:transparent)
(define (+ttf-glyph . args)
(apply +glyph #:constructor ttf-glyph args))
;; Parses just the glyph header and returns the bounding box
#;(define/override (_getCBox internal)
(unfinished))
;; Parses a single glyph coordinate
(define/public (_parseGlyphCoord port prev short same)
(unless (input-port? port)
(raise-argument-error '_parseGlyphCoord "input port" port))
(unless (number? prev)
(raise-argument-error '_parseGlyphCoord "number" prev))
(unless (and (boolean? short) (boolean? same))
(raise-argument-error '_parseGlyphCoord "booleans" (list short same)))
(+ prev (if short
((if (not same) - +) (decode uint8 port))
(if same 0 (decode int16be port)))))
;; Parses a single glyph coordinate
(define (_parseGlyphCoord port prev short same)
(unless (input-port? port)
(raise-argument-error '_parseGlyphCoord "input port" port))
(unless (number? prev)
(raise-argument-error '_parseGlyphCoord "number" prev))
(unless (and (boolean? short) (boolean? same))
(raise-argument-error '_parseGlyphCoord "booleans" (list short same)))
(+ prev (if short
((if (not same) - +) (decode uint8 port))
(if same 0 (decode int16be port)))))
;; Decodes the glyph data into points for simple glyphs,
;; or components for composite glyphs
(define/public (_decode)
(define offsets (· _font loca offsets))
(match-define (list glyfPos nextPos) (take (drop offsets id) 2))
;; Nothing to do if there is no data for this glyph
(and (not (= glyfPos nextPos))
(let ()
(define port (send _font _getTableStream 'glyf))
(pos port (+ (pos port) glyfPos))
(define startPos (pos port))
(define glyph (decode GlyfHeader port))
(match (· glyph numberOfContours)
[(? positive?) (_decodeSimple glyph port)]
[(? negative?) (_decodeComposite glyph port startPos)])
glyph)))
(define/public (_decodeSimple glyph port)
(unless (dict? glyph)
(raise-argument-error 'TTFGlyph-_decodeSimple "decoded RGlyfHeader" glyph))
(unless (input-port? port)
(raise-argument-error 'TTFGlyph-_decodeSimple "input port" port))
;; this is a simple glyph
(dict-set! glyph 'points empty)
(define endPtsOfContours (decode (+Array uint16be (· glyph numberOfContours)) port))
(dict-set! glyph 'instructions (decode (+Array uint8be uint16be) port))
(define numCoords (add1 (last endPtsOfContours)))
(define flags
(for*/lists (flags)
([i (in-naturals)]
#:break (= (length flags) numCoords)
[flag (in-value (decode uint8 port))]
[count (in-range (add1 (if (not (zero? (bitwise-and flag REPEAT)))
(decode uint8 port)
0)))])
flag))
(match-define-values
(points _ _)
(for/fold ([points empty] [px 0] [py 0])
([(flag i) (in-indexed flags)])
(define point (+Point (zero? (bitwise-and flag ON_CURVE)) (and (index-of endPtsOfContours i) #t) 0 0))
(define next-px (_parseGlyphCoord port px (not (zero? (bitwise-and flag X_SHORT_VECTOR))) (not (zero? (bitwise-and flag SAME_X)))))
(define next-py (_parseGlyphCoord port py (not (zero? (bitwise-and flag Y_SHORT_VECTOR))) (not (zero? (bitwise-and flag SAME_Y)))))
(set-field! x point next-px)
(set-field! y point next-py)
(values (cons point points) next-px next-py)))
(dict-set! glyph 'points (reverse points)))
(define/public (_decodeComposite glyph port [offset 0])
;; this is a composite glyph
(dict-set! glyph 'components empty)
(define haveInstructions #f)
(define flags MORE_COMPONENTS)
(dict-set! glyph 'components
(for/list ([i (in-naturals)]
#:break (zero? (bitwise-and flags MORE_COMPONENTS)))
(set! flags (send uint16be decode port))
(define gPos (- (pos port) offset))
(define glyphID (send uint16be decode port))
(unless haveInstructions
(set! haveInstructions (not (zero? (bitwise-and flags WE_HAVE_INSTRUCTIONS)))))
(match-define
(list dx dy)
(let ([decoder (if (not (zero? (bitwise-and flags ARG_1_AND_2_ARE_WORDS))) int16be int8)])
(list (send decoder decode port) (send decoder decode port))))
(define component (+Component glyphID dx dy))
(set-field! pos component gPos)
(cond
[(not (zero? (bitwise-and flags WE_HAVE_A_SCALE)))
(define scale (read-fixed14 port))
(set-field! scaleX component scale)
(set-field! scaleY component scale)]
[(not (zero? (bitwise-and flags WE_HAVE_AN_X_AND_Y_SCALE)))
(set-field! scaleX component (read-fixed14 port))
(set-field! scaleY component (read-fixed14 port))]
[(not (zero? (bitwise-and flags WE_HAVE_A_TWO_BY_TWO)))
(set-field! scaleX component (read-fixed14 port))
(set-field! scale01 component (read-fixed14 port))
(set-field! scale10 component (read-fixed14 port))
(set-field! scaleY component (read-fixed14 port))])
component))
haveInstructions))
;; Decodes the glyph data into points for simple glyphs,
;; or components for composite glyphs
(define (glyph-decode ttfg)
(define offsets (· (glyph-_font ttfg) loca offsets))
(match-define (list glyfPos nextPos) (take (drop offsets (glyph-id ttfg)) 2))
;; Nothing to do if there is no data for this glyph
(and (not (= glyfPos nextPos))
(let ()
(define port (send (glyph-_font ttfg) _getTableStream 'glyf))
(pos port (+ (pos port) glyfPos))
(define startPos (pos port))
(define glyph (decode GlyfHeader port))
(match (· glyph numberOfContours)
[(? positive?) (_decodeSimple glyph port)]
[(? negative?) (_decodeComposite glyph port startPos)])
glyph)))
(define (_decodeSimple glyph port)
(unless (dict? glyph)
(raise-argument-error 'TTFGlyph-_decodeSimple "decoded RGlyfHeader" glyph))
(unless (input-port? port)
(raise-argument-error 'TTFGlyph-_decodeSimple "input port" port))
;; this is a simple glyph
(dict-set! glyph 'points empty)
(define endPtsOfContours (decode (+Array uint16be (· glyph numberOfContours)) port))
(dict-set! glyph 'instructions (decode (+Array uint8be uint16be) port))
(define numCoords (add1 (last endPtsOfContours)))
(define flags
(for*/lists (flags)
([i (in-naturals)]
#:break (= (length flags) numCoords)
[flag (in-value (decode uint8 port))]
[count (in-range (add1 (if (not (zero? (bitwise-and flag REPEAT)))
(decode uint8 port)
0)))])
flag))
(match-define-values
(points _ _)
(for/fold ([points empty] [px 0] [py 0])
([(flag i) (in-indexed flags)])
(define point (+Point (zero? (bitwise-and flag ON_CURVE)) (and (index-of endPtsOfContours i) #t) 0 0))
(define next-px (_parseGlyphCoord port px (not (zero? (bitwise-and flag X_SHORT_VECTOR))) (not (zero? (bitwise-and flag SAME_X)))))
(define next-py (_parseGlyphCoord port py (not (zero? (bitwise-and flag Y_SHORT_VECTOR))) (not (zero? (bitwise-and flag SAME_Y)))))
(set-field! x point next-px)
(set-field! y point next-py)
(values (cons point points) next-px next-py)))
(dict-set! glyph 'points (reverse points)))
(define (_decodeComposite glyph port [offset 0])
;; this is a composite glyph
(dict-set! glyph 'components empty)
(define haveInstructions #f)
(define flags MORE_COMPONENTS)
(dict-set! glyph 'components
(for/list ([i (in-naturals)]
#:break (zero? (bitwise-and flags MORE_COMPONENTS)))
(set! flags (send uint16be decode port))
(define gPos (- (pos port) offset))
(define glyphID (send uint16be decode port))
(unless haveInstructions
(set! haveInstructions (not (zero? (bitwise-and flags WE_HAVE_INSTRUCTIONS)))))
(match-define
(list dx dy)
(let ([decoder (if (not (zero? (bitwise-and flags ARG_1_AND_2_ARE_WORDS))) int16be int8)])
(list (send decoder decode port) (send decoder decode port))))
(define component (+Component glyphID dx dy))
(set-field! pos component gPos)
(cond
[(not (zero? (bitwise-and flags WE_HAVE_A_SCALE)))
(define scale (read-fixed14 port))
(set-field! scaleX component scale)
(set-field! scaleY component scale)]
[(not (zero? (bitwise-and flags WE_HAVE_AN_X_AND_Y_SCALE)))
(set-field! scaleX component (read-fixed14 port))
(set-field! scaleY component (read-fixed14 port))]
[(not (zero? (bitwise-and flags WE_HAVE_A_TWO_BY_TWO)))
(set-field! scaleX component (read-fixed14 port))
(set-field! scale01 component (read-fixed14 port))
(set-field! scale10 component (read-fixed14 port))
(set-field! scaleY component (read-fixed14 port))])
component))
haveInstructions)
(define (bytes->fixed14 b1 b2)

3
fontland/fontland/main.rkt
Unescape Escape View File

@ -8,4 +8,5 @@
"subset.rkt"
"bbox.rkt"
"tables.rkt"
"glyphrun.rkt")
"glyphrun.rkt"
"glyph.rkt")

11
fontland/fontland/subset.rkt
Unescape Escape View File

@ -10,6 +10,7 @@
"table/loca.rkt"
"directory.rkt"
"helper.rkt"
fontland/glyph
xenomorph)
(provide Subset TTFSubset)
@ -103,12 +104,12 @@ https://github.com/mbutterick/fontkit/blob/master/src/subset/TTFSubset.js
(index? . ->m . index?)
(define glyph (send (· this font) getGlyph gid))
;; _decode unpacks the `glyf` table data corresponding to a certin gid.
;; glyph-decode unpacks the `glyf` table data corresponding to a certin gid.
;; here, it's not necessary for non-composite glyphs
;; because they just get copied entirely into the subset.
;; it's just used to detect composite glyphs and handle them specially.
;; so an optimization would be to detect composite / noncomposite without full _decode.
(define glyf (send glyph _decode))
;; so an optimization would be to detect composite / noncomposite without full glyph-decode.
(define glyf (glyph-decode glyph))
;; get the offset to the glyph from the loca table
(match-define (list curOffset nextOffset) (take (drop (· this font loca offsets) gid) 2))
@ -132,8 +133,8 @@ https://github.com/mbutterick/fontkit/blob/master/src/subset/TTFSubset.js
(append os (list (get-field offset this)))))
(hash-update! (get-field hmtx this) 'metrics (λ (ms) (append ms
(list (mhash 'advance (· glyph advanceWidth)
'bearing (· (send glyph _getMetrics) leftBearing))))))
(list (mhash 'advance (glyph-advance-width glyph)
'bearing (· (_getMetrics glyph) leftBearing))))))
(increment-field! offset this (bytes-length buffer))
(sub1 (length (· this glyf))))

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