methodize image

main
Matthew Butterick 6 years ago
parent b62b95b66e
commit ae1623ecc1

@ -1,32 +1,19 @@
#lang racket/base
(require
"helper.rkt"
racket/class
racket/contract
"jpeg.rkt"
"png.rkt")
(provide PDFImage-open)
#;(define PDFImage
(class object%
(super-new)
(as-methods
)))
(define/contract (PDFImage-open src label)
(any/c any/c . -> . (or/c (is-a?/c PNG) (is-a?/c JPEG)))
(define (PDFImage-open src label)
(define data (cond
[(bytes? src) src]
;;else if src instanceof ArrayBuffer
;;data = new Buffer(new Uint8Array(src))
[(regexp-match #rx"^data:.+;base64,(.*)$" src)
(void)] ;; base64 ; todo
[(bytes? src) (open-input-bytes src)]
[(regexp-match #rx"^data:.+;base64,(.*)$" src) (void)] ;; base64 ; todo
[else (open-input-file src)]))
(cond
[(equal? (peek-bytes 2 0 data) (bytes #xff #xd8))
(make-object JPEG data label)]
[(equal? (peek-bytes 4 0 data) (apply bytes (cons #x89 (map char->integer '(#\P #\N #\G)))))
(make-object PNG data label)]
[else (raise-argument-error 'PDFImage-open "valid image format" src)]))
(define image-class
(cond
[(equal? (peek-bytes 2 0 data) (bytes #xff #xd8)) JPEG]
[(equal? (peek-bytes 4 0 data) (apply bytes (map char->integer '(#\u0089 #\P #\N #\G)))) PNG]
[else (raise-argument-error 'PDFImage-open "valid image format" src)]))
(make-object image-class data label))

Loading…
Cancel
Save