gbye
parent
7e133ab2fc
commit
4b2c1017a7
@ -1,181 +0,0 @@
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#lang racket/base
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(require "racket.rkt")
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(require "glyph.rkt" xenomorph)
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(provide (all-defined-out))
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#|
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approximates
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https://github.com/mbutterick/fontkit/blob/master/src/glyph/TTFGlyph.js
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|#
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;; The header for both simple and composite glyphs
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(define-subclass Struct (RGlyfHeader))
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(define GlyfHeader (+RGlyfHeader
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(dictify 'numberOfContours int16be ;; if negative, this is a composite glyph
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'xMin int16be
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'yMin int16be
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'xMax int16be
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'yMax int16be)))
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;; Flags for simple glyphs
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(define-macro (define-flag-series . IDS)
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#`(match-define (list . IDS) (map (curry expt 2) (range #,(length (syntax->list #'IDS))))))
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;; Flags for simple glyphs
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(define-flag-series ON_CURVE
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X_SHORT_VECTOR
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Y_SHORT_VECTOR
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REPEAT
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SAME_X
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SAME_Y)
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;; Flags for composite glyphs
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(define-flag-series ARG_1_AND_2_ARE_WORDS
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ARGS_ARE_XY_VALUES
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ROUND_XY_TO_GRID
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WE_HAVE_A_SCALE
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__EMPTY-FLAG___
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MORE_COMPONENTS
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WE_HAVE_AN_X_AND_Y_SCALE
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WE_HAVE_A_TWO_BY_TWO
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WE_HAVE_INSTRUCTIONS
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USE_MY_METRICS
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OVERLAP_COMPOUND
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SCALED_COMPONENT_OFFSET
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UNSCALED_COMPONENT_OFFSET)
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;; Represents a point in a simple glyph
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(define-subclass object% (Point onCurve endContour [x 0] [y 0])
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(define/public (copy)
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(+Point onCurve endContour x y)))
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;; Represents a component in a composite glyph
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(define-subclass object% (Component glyphID dx dy)
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(field [pos 0]
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[scaleX 1]
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[scaleY 1]
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[scale01 0]
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[scale10 0]))
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;; Represents a TrueType glyph.
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(define-subclass Glyph (TTFGlyph)
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(inherit-field _font id)
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;; Parses just the glyph header and returns the bounding box
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(define/override (_getCBox internal)
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(unfinished))
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;; Parses a single glyph coordinate
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(define/public (_parseGlyphCoord port prev short same)
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(unless (input-port? port)
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(raise-argument-error '_parseGlyphCoord "input port" port))
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(unless (number? prev)
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(raise-argument-error '_parseGlyphCoord "number" prev))
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(unless (and (boolean? short) (boolean? same))
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(raise-argument-error '_parseGlyphCoord "booleans" (list short same)))
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(+ prev (if short
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((if (not same) - +) (decode uint8 port))
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(if same 0 (decode int16be port)))))
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;; Decodes the glyph data into points for simple glyphs,
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;; or components for composite glyphs
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(define/public (_decode)
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(define offsets (· _font loca offsets))
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(match-define (list glyfPos nextPos) (take (drop offsets id) 2))
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;; Nothing to do if there is no data for this glyph
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(and (not (= glyfPos nextPos))
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(let ()
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(define port (send _font _getTableStream 'glyf))
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(pos port (+ (pos port) glyfPos))
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(define startPos (pos port))
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(define glyph (decode GlyfHeader port))
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(match (· glyph numberOfContours)
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[(? positive?) (_decodeSimple glyph port)]
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[(? negative?) (_decodeComposite glyph port startPos)])
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glyph)))
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(define/public (_decodeSimple glyph port)
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(unless (dict? glyph)
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(raise-argument-error 'TTFGlyph-_decodeSimple "decoded RGlyfHeader" glyph))
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(unless (input-port? port)
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(raise-argument-error 'TTFGlyph-_decodeSimple "input port" port))
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;; this is a simple glyph
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(dict-set! glyph 'points empty)
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(define endPtsOfContours (decode (+Array uint16be (· glyph numberOfContours)) port))
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(dict-set! glyph 'instructions (decode (+Array uint8be uint16be) port))
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(define numCoords (add1 (last endPtsOfContours)))
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(define flags
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(for*/lists (flags)
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([i (in-naturals)]
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#:break (= (length flags) numCoords)
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[flag (in-value (decode uint8 port))]
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[count (in-range (add1 (if (not (zero? (bitwise-and flag REPEAT)))
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(decode uint8 port)
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0)))])
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flag))
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(match-define-values
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(points _ _)
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(for/fold ([points empty] [px 0] [py 0])
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([(flag i) (in-indexed flags)])
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(define point (+Point (zero? (bitwise-and flag ON_CURVE)) (and (index-of endPtsOfContours i) #t) 0 0))
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(define next-px (_parseGlyphCoord port px (not (zero? (bitwise-and flag X_SHORT_VECTOR))) (not (zero? (bitwise-and flag SAME_X)))))
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(define next-py (_parseGlyphCoord port py (not (zero? (bitwise-and flag Y_SHORT_VECTOR))) (not (zero? (bitwise-and flag SAME_Y)))))
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(set-field! x point next-px)
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(set-field! y point next-py)
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(values (cons point points) next-px next-py)))
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(dict-set! glyph 'points (reverse points)))
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(define/public (_decodeComposite glyph port [offset 0])
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;; this is a composite glyph
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(dict-set! glyph 'components empty)
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(define haveInstructions #f)
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(define flags MORE_COMPONENTS)
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(dict-set! glyph 'components
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(for/list ([i (in-naturals)]
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#:break (zero? (bitwise-and flags MORE_COMPONENTS)))
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(set! flags (send uint16be decode port))
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(define gPos (- (pos port) offset))
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(define glyphID (send uint16be decode port))
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(unless haveInstructions
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(set! haveInstructions (not (zero? (bitwise-and flags WE_HAVE_INSTRUCTIONS)))))
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(match-define
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(list dx dy)
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(let ([decoder (if (not (zero? (bitwise-and flags ARG_1_AND_2_ARE_WORDS))) int16be int8)])
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(list (send decoder decode port) (send decoder decode port))))
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(define component (+Component glyphID dx dy))
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(set-field! pos component gPos)
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(cond
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[(not (zero? (bitwise-and flags WE_HAVE_A_SCALE)))
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(define scale (read-fixed14 port))
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(set-field! scaleX component scale)
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(set-field! scaleY component scale)]
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[(not (zero? (bitwise-and flags WE_HAVE_AN_X_AND_Y_SCALE)))
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(set-field! scaleX component (read-fixed14 port))
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(set-field! scaleY component (read-fixed14 port))]
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[(not (zero? (bitwise-and flags WE_HAVE_A_TWO_BY_TWO)))
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(set-field! scaleX component (read-fixed14 port))
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(set-field! scale01 component (read-fixed14 port))
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(set-field! scale10 component (read-fixed14 port))
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(set-field! scaleY component (read-fixed14 port))])
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component))
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haveInstructions))
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(define (bytes->fixed14 b1 b2)
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(/ (+ (* b1 (expt 2 8)) b2) (expt 2 14) 1.0))
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(define (read-fixed14 stream)
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(define b1 (send uint8 decode stream))
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(define b2 (send uint8 decode stream))
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(bytes->fixed14 b1 b2))
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@ -1,13 +0,0 @@
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#lang racket/base
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(require "racket.rkt")
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(provide TTFGlyphEncoder)
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(define-subclass object% (TTFGlyphEncoder)
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(as-methods
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encodeSimple
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_encodePoint))
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(define-stub encodeSimple)
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(define-stub _encodePoint)
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