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typesetting/pitfall/fontkit/head.rkt

63 lines
3.1 KiB
Racket

#lang fontkit/racket
(require restructure)
(provide (all-defined-out))
#|
approximates
https://github.com/mbutterick/fontkit/blob/master/src/tables/head.js
|#
(define-subclass Struct (Rhead))
(define head (make-object Rhead
(dictify
'version int32be ;; 0x00010000 (version 1.0)
'revision int32be ;; set by font manufacturer
'checkSumAdjustment uint32be
'magicNumber uint32be ;; set to 0x5F0F3CF5
'flags uint16be
'unitsPerEm uint16be ;; range from 64 to 16384
'created (+Array int32be 2)
'modified (+Array int32be 2)
'xMin int16be ;; for all glyph bounding boxes
'yMin int16be ;; for all glyph bounding boxes
'xMax int16be ;; for all glyph bounding boxes
'yMax int16be ;; for all glyph bounding boxes
'macStyle (+Bitfield uint16be '(bold italic underline outline shadow condensed extended))
'lowestRecPPEM uint16be ;; smallest readable size in pixels
'fontDirectionHint int16be
'indexToLocFormat int16be ;; 0 for short offsets 1 for long
'glyphDataFormat int16be ;; 0 for current format
)))
(test-module
(require racket/serialize)
(define ip (open-input-file charter-italic-path))
(define dir (deserialize (read (open-input-file charter-italic-directory-path))))
(define offset (· dir tables head offset))
(define length (· dir tables head length))
(check-equal? offset 236)
(check-equal? length 54)
(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")
(set-port-position! ip 0)
(check-equal? (peek-bytes length offset ip) table-bytes)
(define table-data (send head decode (+DecodeStream table-bytes)))
(check-equal? (· table-data unitsPerEm) 1000)
(check-equal? (· table-data yMin) -236)
(check-equal? (· table-data yMax) 980)
(check-equal? (· table-data xMax) 1174)
(check-equal? (· table-data xMin) -226)
(check-equal? (· table-data macStyle) (make-hash '((shadow . #f)
(extended . #f)
(condensed . #f)
(underline . #f)
(outline . #f)
(bold . #f)
(italic . #t))))
(check-equal? (· table-data magicNumber) #x5F0F3CF5)
(check-equal? (· table-data indexToLocFormat) 0) ; used in loca table
(define es (+EncodeStream))
(send head encode es table-data)
(check-equal? (send es dump) table-bytes))