added documentation for the flipping functions

collects/teachpack/2htdp/scribblings/image-gen.rkt

@@ -38,7 +38,7 @@
          (with-handlers ([exn:fail?
                           (λ (x)
                             (printf "\nerror evaluating:\n")
-                            (pretty-print exp)
+                            (pretty-write exp)
                             (raise x))])
            (parameterize ([current-namespace image-ns]) (eval exp)))])
     (cond
@@ -107,7 +107,7 @@
      (λ (port)
        (fprintf port "#lang racket/base\n(provide mapping)\n")
        (fprintf port ";; this file is generated by image-gen.ss -- do not edit\n;; note that the file that creates this file depends on this file\n;; it is always safe to simply define (and provide) mapping as the empty list\n\n")
-       (pretty-print
+       (pretty-write
         `(define mapping (list ,@mapping))
         port))
      #:exists 'truncate)])

collects/teachpack/2htdp/scribblings/image-toc.rkt

@@ -1,4 +1,4 @@
-#lang scheme/base
+#lang racket/base
 (provide mapping)
 ;; this file is generated by image-gen.ss -- do not edit
 ;; note that the file that creates this file depends on this file
@@ -53,6 +53,18 @@
     '(crop 0 0 40 40 (circle 40 "solid" "chocolate"))
     'image
     "8e7c1870c7.png")
+   (list
+    '(above
+      (star 40 "solid" "firebrick")
+      (scale/xy 1 1/2 (flip-vertical (star 40 "solid" "gray"))))
+    'image
+    "25bd9b1ac5a.png")
+   (list
+    '(beside
+      (rotate 30 (square 50 "solid" "red"))
+      (flip-horizontal (rotate 30 (square 50 "solid" "blue"))))
+    'image
+    "e58911226.png")
    (list '(ellipse 60 60 "solid" "blue") 'image "d92d6a49f1.png")
    (list
     '(scale/xy 3 2 (ellipse 20 30 "solid" "blue"))

collects/teachpack/2htdp/scribblings/image.scrbl

@@ -764,7 +764,7 @@ the parts that fit onto @racket[scene].
 }
 
                 
-@section{Rotating, Scaling, Cropping, and Framing Images}
+@section{Rotating, Scaling, Flipping, Cropping, and Framing Images}
 
 @defproc[(rotate [angle angle?] [image image?]) image?]{
   Rotates @racket[image] by @racket[angle] degrees in a counter-clockwise direction.
@@ -809,6 +809,23 @@ the parts that fit onto @racket[scene].
                   (ellipse 60 60 "solid" "blue")]
 }
 
+@defproc[(flip-horizontal [image image?]) image?]{
+   Flips @scheme[image] left to right.
+         
+         @image-examples[(beside
+                          (rotate 30 (square 50 "solid" "red"))
+                          (flip-horizontal
+                           (rotate 30 (square 50 "solid" "blue"))))]
+}
+
+@defproc[(flip-vertical [image image?]) image?]{
+   Flips @scheme[image] top to bottom.
+         
+         @image-examples[(above 
+                          (star 40 "solid" "firebrick")
+                          (scale/xy 1 1/2 (flip-vertical (star 40 "solid" "gray"))))]
+}
+
 @defproc[(crop [x real?] [y real?] 
                [width (and/c real? (not/c negative?))]
                [height (and/c real? (not/c negative?))]