Move calculate-fg-color into calp subtree.

While the algorithm was general, the packing of colors, along with the
error handling made it to non-portable.

3 files changed, 21 insertions, 24 deletions

diff --git a/module/calp/html/util.scm b/module/calp/html/util.scm
index ecb54198..75137d4e 100644
--- a/module/calp/html/util.scm
+++ b/module/calp/html/util.scm
@@ -13,3 +13,23 @@
     (lambda (ev)
       (or (id ev)
           (set/r! (id ev) (symbol->string (gensym "__html_id_")))))))
+
+;; Returns a color with good contrast to the given background color.
+;; https://stackoverflow.com/questions/1855884/determine-font-color-based-on-background-color/1855903#1855903
+(define-public (calculate-fg-color c)
+  (catch #t
+    (lambda ()
+      (define (str->num c n) (string->number (substring/shared c n (+ n 2)) 16))
+      ;; (format (current-error-port) "COLOR = ~s~%" c)
+      (let ((r (str->num c 1))
+            (g (str->num c 3))
+            (b (str->num c 5)))
+        (if (< 1/2 (/ (+ (* 0.299 r)
+                         (* 0.587 g)
+                         (* 0.114 b))
+                      #xFF))
+            "#000000" "#FFFFFF")))
+    (lambda args
+      (format (current-error-port) "Error calculating foreground color?~%~s~%" args)
+      "#FF0000"
+      )))
diff --git a/module/calp/html/vcomponent.scm b/module/calp/html/vcomponent.scm
index 4c1ebbb3..16f418c5 100644
--- a/module/calp/html/vcomponent.scm
+++ b/module/calp/html/vcomponent.scm
@@ -10,10 +10,9 @@
   :use-module (datetime)
   :use-module ((text util) :select (add-enumeration-punctuation))
   :use-module ((web uri-query) :select (encode-query-parameters))
-  :use-module (calp html util)
+  :use-module ((calp html util) :select (html-id calculate-fg-color))
   :use-module ((calp html config) :select (edit-mode debug))
   :use-module ((calp html components) :select (btn tabset form with-label))
-  :use-module ((hnh util color) :select (calculate-fg-color))
   :use-module ((crypto) :select (sha256 checksum->string))
   :use-module ((xdg basedir) :prefix xdg-)
   :use-module ((vcomponent recurrence) :select (repeating?))
diff --git a/module/hnh/util/color.scm b/module/hnh/util/color.scm
deleted file mode 100644
index b626316d..00000000
--- a/module/hnh/util/color.scm
+++ /dev/null
@@ -1,22 +0,0 @@
-(define-module (hnh util color)
-  )
-
-;; Returns a color with good contrast to the given background color.
-;; https://stackoverflow.com/questions/1855884/determine-font-color-based-on-background-color/1855903#1855903
-(define-public (calculate-fg-color c)
-  (catch #t
-    (lambda ()
-      (define (str->num c n) (string->number (substring/shared c n (+ n 2)) 16))
-      ;; (format (current-error-port) "COLOR = ~s~%" c)
-      (let ((r (str->num c 1))
-            (g (str->num c 3))
-            (b (str->num c 5)))
-        (if (< 1/2 (/ (+ (* 0.299 r)
-                         (* 0.587 g)
-                         (* 0.114 b))
-                      #xFF))
-            "#000000" "#FFFFFF")))
-    (lambda args
-      (format (current-error-port) "Error calculating foreground color?~%~s~%" args)
-      "#FF0000"
-      )))