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59 lines
3.2 KiB
Racket
59 lines
3.2 KiB
Racket
#lang racket/base
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(require xenomorph)
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(provide head)
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#|
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approximates
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https://github.com/mbutterick/fontkit/blob/master/src/tables/head.js
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|#
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(define head (x:struct
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'version int32be ;; 0x00010000 (version 1.0)
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'revision int32be ;; set by font manufacturer
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'checkSumAdjustment uint32be
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'magicNumber uint32be ;; set to 0x5F0F3CF5
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'flags uint16be
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'unitsPerEm uint16be ;; range from 64 to 16384
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'created (x:array #:type int32be #:length 2)
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'modified (x:array #:type int32be #:length 2)
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'xMin int16be ;; for all glyph bounding boxes
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'yMin int16be ;; for all glyph bounding boxes
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'xMax int16be ;; for all glyph bounding boxes
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'yMax int16be ;; for all glyph bounding boxes
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'macStyle (x:bitfield #:type uint16be
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#:flags '(bold italic underline outline shadow condensed extended))
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'lowestRecPPEM uint16be ;; smallest readable size in pixels
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'fontDirectionHint int16be
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'indexToLocFormat int16be ;; 0 for short offsets 1 for long
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'glyphDataFormat int16be ;; 0 for current format
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))
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(module+ test
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(require rackunit "../helper.rkt"
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racket/serialize)
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(define ip (open-input-file charter-italic-path))
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(define dir (deserialize (read (open-input-file charter-italic-directory-path))))
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(define offset (hash-ref (hash-ref (hash-ref dir 'tables) 'head) 'offset))
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(define length (hash-ref (hash-ref (hash-ref dir 'tables) 'head) 'length))
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(check-equal? offset 236)
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(check-equal? length 54)
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(define table-bytes #"\0\1\0\0\0\2\0\0.\252t<_\17<\365\0\t\3\350\0\0\0\0\316\3\301\261\0\0\0\0\316\3\304\364\377\36\377\24\4\226\3\324\0\2\0\t\0\2\0\0\0\0")
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(file-position ip 0)
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(check-equal? (peek-bytes length offset ip) table-bytes)
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(define table-data (decode head table-bytes))
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(check-equal? (hash-ref table-data 'unitsPerEm) 1000)
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(check-equal? (hash-ref table-data 'yMin) -236)
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(check-equal? (hash-ref table-data 'yMax) 980)
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(check-equal? (hash-ref table-data 'xMax) 1174)
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(check-equal? (hash-ref table-data 'xMin) -226)
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(check-equal? (hash-ref table-data 'macStyle) (make-hash '((shadow . #f)
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(extended . #f)
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(condensed . #f)
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(underline . #f)
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(outline . #f)
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(bold . #f)
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(italic . #t))))
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(check-equal? (hash-ref table-data 'magicNumber) #x5F0F3CF5)
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(check-equal? (hash-ref table-data 'indexToLocFormat) 0) ; used in loca table
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(check-equal? (encode head table-data #f) table-bytes)) |