Added #:unscaled? keyword argument to `bitmap->flomap'

pkgs/images-pkgs/images-doc/images/scribblings/flomap.scrbl

@@ -327,7 +327,7 @@ Like @racket[unsafe-flomap-ref], but returns an flvector containing all the comp
                                                                                           
 @section{Conversion and Construction}
 
-@defproc[(flomap->bitmap [fm flomap] [#:backing-scale backing-scale (>/c 0.0)]) Any]{
+@defproc[(flomap->bitmap [fm flomap] [#:backing-scale backing-scale Positive-Real]) Any]{
 Converts a flomap to a @racket[bitmap%].
 
 The return type is imprecise because Typed Racket does not support the object system well yet.
@@ -350,10 +350,13 @@ For example, if @racket[fm] is size 0×1, the result of @racket[(flomap->bitmap
 Values are clamped to between @racket[0.0] and @racket[1.0] before conversion.
 }
 
-@defproc[(bitmap->flomap [bm Any]) flomap]{
-Given a @racket[bitmap%] instance, returns an ARGB flomap with alpha-multiplied color components.
+@defproc[(bitmap->flomap [bm Any] [#:unscaled? unscaled? Any]) flomap]{
+Given a @racket[bitmap%] instance @racket[bm], returns an ARGB flomap with alpha-multiplied color components.
 See @secref{flomap:opacity} for a discussion of opacity (alpha) representation.
 
+If @racket[unscaled?] is true, the flomap is converted from the actual bitmap backing @racket[bm] rather than a scaled version.
+See the @racket[#:unscaled?] keyword parameter of @method[bitmap% get-argb-pixels] for more information.
+
 The argument type is imprecise because Typed Racket does not support the object system well yet.
 }
 

pkgs/images-pkgs/images-lib/images/private/flomap-convert.rkt

@@ -8,14 +8,19 @@
 
 (provide bitmap->flomap flomap->bitmap draw-flomap)
 
-(define (bitmap->flomap bm)
+(define (bitmap->flomap bm #:unscaled? [unscaled? #f])
   (unless (is-a? bm bitmap%)
     (raise-type-error 'bitmap->flomap "bitmap% instance" bm))
-  (define w (send bm get-width))
-  (define h (send bm get-height))
+  
+  (define backing-scale (send bm get-backing-scale))
+  (define (scale d)
+    (if unscaled? (inexact->exact (ceiling (* d backing-scale))) d))
+  
+  (define w (scale (send bm get-width)))
+  (define h (scale (send bm get-height)))
   (define bs (make-bytes (* 4 w h)))
-  (send bm get-argb-pixels 0 0 w h bs #t #t)
-  (send bm get-argb-pixels 0 0 w h bs #f #t)
+  (send bm get-argb-pixels 0 0 w h bs #t #t #:unscaled? unscaled?)
+  (send bm get-argb-pixels 0 0 w h bs #f #t #:unscaled? unscaled?)
   
   (define argb-fm (make-flomap 4 w h))
   (define argb-vs (flomap-values argb-fm))

pkgs/images-pkgs/images-lib/images/private/flomap.rkt

@@ -29,7 +29,7 @@
 
 (require/typed
  "flomap-convert.rkt"
- [bitmap->flomap  ((Instance Bitmap%) -> flomap)]
+ [bitmap->flomap  ((Instance Bitmap%) [#:unscaled? Any] -> flomap)]
  [flomap->bitmap  (flomap [#:backing-scale Positive-Real] -> (Instance Bitmap%))]
  [draw-flomap     ((Any -> Any) Integer Integer -> flomap)])