methodize image

pitfall/pitfall/image.rkt

@@ -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))