Data commit

Task/Bitmap-Read-an-image-through-a-pipe/Racket/bitmap-read-an-image-through-a-pipe.rkt

@@ -0,0 +1,30 @@
+(define (read-ppm port)
+  (parameterize ([current-input-port port])
+    (define magic (read-line))
+    (match-define (list w h) (string-split (read-line) " "))
+    (define width (string->number w))
+    (define height (string->number h))
+    (define maxcol (string->number (read-line)))
+    (define bm (make-object bitmap% width height))
+    (define dc (new bitmap-dc% [bitmap bm]))
+    (send dc set-smoothing 'unsmoothed)
+    (define (adjust v) (* 255 (/ v maxcol)))
+    (for/list ([x width])
+      (for/list ([y height])
+        (define red (read-byte))
+        (define green (read-byte))
+        (define blue (read-byte))
+        (define color (make-object color% (adjust red) (adjust green) (adjust blue)))
+        (send dc set-pen color 1 'solid)
+        (send dc draw-point x y)))
+    bm))
+
+(define (image->bmp filename)
+  (define command (format "convert ~a ppm:-" filename))
+  (match-define (list in out pid err ctrl)  (process command))
+  (define bmp (read-ppm in))
+  (close-input-port in)
+  (close-output-port out)
+  bmp)
+
+(image->bmp "input.jpg")