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20 lines
670 B
Racket
20 lines
670 B
Racket
#lang racket/base
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(require
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racket/class
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"jpeg.rkt"
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"png.rkt")
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(provide PDFImage-open)
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(define (PDFImage-open src label)
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(define data (cond
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[(bytes? src) (open-input-bytes src)]
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[(regexp-match #rx"^data:.+;base64,(.*)$" src) (void)] ;; base64 ; todo
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[else (open-input-file src)]))
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(define img-constructor
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(cond
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[(equal? (peek-bytes 2 0 data) (bytes #xff #xd8)) make-jpeg]
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[(equal? (peek-bytes 4 0 data) (apply bytes (map char->integer '(#\u0089 #\P #\N #\G)))) make-png]
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[else (raise-argument-error 'PDFImage-open "valid image format" src)]))
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(img-constructor data label))
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