Support for screenshots in @instructionsteps

defs.rkt

 #lang racket/base
 (require scribble/base)
+(require scribble/decode)
+(require racket/class)
+(require racket/draw)
 
 (provide (all-defined-out))
 
-(define (apturl page)
-  (string-append "https://www.aptlab.net/" page))
+(define apt-base-url "https://www.aptlab.net/")
+
+(define screenshot-width 650)
+
+(define apturl
+  (case-lambda
+    [() apt-base-url]
+    [(page) (string-append apt-base-url page)]))
 
 (define (TODO . what)
-  (bold "TODO: " what))
+  (bold "TODO: " (decode-content what)))
 
 (define nodetype
   (lambda (typename howmany . properties)
@@ -16,3 +25,15 @@
                      (list (bold typename)
                            (string-append (number->string howmany) " nodes"))
                      properties))))
+
+(define (instructionstep step #:screenshot [screenshot #f] . body)
+  (item (bold (decode-content (list step)))
+        (linebreak)
+        (if screenshot
+          (let* ([path (string-append "screenshots/" screenshot)]
+                 [b (make-object bitmap% path)]
+                 [width (send b get-width)]
+                 [scale-factor (/ screenshot-width width)])
+            (list (image #:scale scale-factor path screenshot) (linebreak)))
+          (void))
+        (decode-content body)))

getting-started.scrbl

@@ -4,4 +4,14 @@
 
 @title[#:tag "getting-started"]{Getting Started}
 
-@TODO{This Section To Be Written!}
+This chapter will walk you through running a simple experiment on Apt and
+introduce you to some of its basic concepts.
+
+Start by pointing your browser to @url[(apturl)] .
+
+@itemlist[#:style 'ordered
+  @instructionstep["Enter your email address and pick a username"
+                   #:screenshot "instantiate-empty.png"]{
+    Do things
+  }
+]