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typesetting/pitfall/fontkit/head.rkt

53 lines
2.6 KiB
Racket

#lang fontkit/racket
(require restructure)
(provide (all-defined-out))
(define-subclass RStruct (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 (make-object RArray int32be 2)
'modified (make-object RArray 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 uint16be
#|
new 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 "directory.rkt")
(define ip (open-input-file charter-path))
(define dir (directory-decode ip))
(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@\247\22 _\17<\365\0\t\3\350\0\0\0\0\316\3\301?\0\0\0\0\316\3\304\363\377_\377\24\4\251\3\303\0\0\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 (make-object RDecodeStream table-bytes)))
(check-equal? (· table-data unitsPerEm) 1000)
(check-equal? (· table-data yMin) -236)
(check-equal? (· table-data yMax) 963)
(check-equal? (· table-data xMax) 1193)
(check-equal? (· table-data xMin) -161)
(check-equal? (· table-data magicNumber) #x5F0F3CF5))