optional image scale

svn: r9140

original commit: d1ed1a1e52efcd8c0baa17ace233f2572611b4e1

collects/scribble/latex-render.ss

@@ -163,7 +163,7 @@
                       #f)]
                [(image-file? style) 
                 (let ([fn (install-file (image-file-path style))])
-                  (printf "\\includegraphics{~a}" fn))]
+                  (printf "\\includegraphics[scale=~a]{~a}" (image-file-scale style) fn))]
                [else (super render-element e part ri)])))
           (when part-label?
             (printf "''"))

collects/scribble/manual.ss

@@ -257,14 +257,14 @@
 
   ;; String String *-> Element
   ;; an in-lined image, relative to the current directory 
-  (define (image filename-relative-to-source . alt)
+  (define (image #:scale [scale 1.0] filename-relative-to-source . alt)
     (make-element
-     (make-image-file filename-relative-to-source)
+     (make-image-file filename-relative-to-source scale)
      (decode-content alt)))
 
   (define (image/plain filename-relative-to-source . alt)
     (make-element 
-      (make-image-file filename-relative-to-source)
+      (make-image-file filename-relative-to-source 1.0)
       (decode-content alt)))
 
   (define (onscreen . str)

collects/scribble/struct.ss

@@ -174,7 +174,8 @@
 
    [target-url ([addr (or/c string? path?)][style any/c])]
    [url-anchor ([name string?])]
-   [image-file ([path path-string?])])
+   [image-file ([path path-string?]
+                [scale real?])])
 
   ;; ----------------------------------------