From 1c114c3e946814edf61d140015679f8d36f12fcf Mon Sep 17 00:00:00 2001
From: Robby Findler <robby@racket-lang.org>
Date: Fri, 16 Apr 2010 14:43:41 -0400
Subject: [PATCH] made the file work when the cwd is not the files directory

---
 collects/teachpack/2htdp/scribblings/image-gen.ss | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/collects/teachpack/2htdp/scribblings/image-gen.ss b/collects/teachpack/2htdp/scribblings/image-gen.ss
index 145ea91943..708b6c0ac4 100644
--- a/collects/teachpack/2htdp/scribblings/image-gen.ss
+++ b/collects/teachpack/2htdp/scribblings/image-gen.ss
@@ -5,8 +5,12 @@
 
 (require 2htdp/image
          lang/posn
+         scheme/runtime-path
          (only-in 2htdp/private/image-more save-image))
 
+(define-runtime-path image.scrbl "image.scrbl")
+(define-runtime-path img "img")
+
 (define-namespace-anchor anchor)
 (define ns (namespace-anchor->namespace anchor))
 (define expressions
@@ -16,7 +20,7 @@
       (thread
        (λ () 
          (parameterize ([current-output-port out])
-           (dynamic-require "image.scrbl" #f))
+           (dynamic-require image.scrbl #f))
          (close-output-port out)))
       (let loop ()
         (let ([exp (read in)])
@@ -42,7 +46,9 @@
       [(image? result)
        (let ([fn (exp->filename exp)])
          (set! mapping (cons `(list ',exp 'image ,fn) mapping))
-         (save-image result (build-path "img" fn)))]
+         (let ([pth (build-path img fn)])
+           (unless (save-image result pth)
+             (fprintf (current-error-port) "failed to save ~s\n" pth))))]
       [else
        (unless (equal? result (read/write result))
          (error 'handle-image "expression ~s produced ~s, which I can't write"