added a close icon to the yellow warning message

svn: r15611

original commit: 3c4bdf86feeda27ad9de986bf357d1a65fda79c0

collects/mrlib/close-icon.ss

@@ -55,7 +55,8 @@
   (class canvas%
     (inherit get-dc min-width min-height stretchable-width stretchable-height
              get-client-size refresh)
-    (init-field [callback void])
+    (init-field [callback void]
+                [bg-color #f])
     (init [horizontal-pad 4]
           [vertical-pad 4])
     (init-masks)
@@ -92,6 +93,11 @@
     (define/override (on-paint)
       (let ([dc (get-dc)])
         (let-values ([(cw ch) (get-client-size)])
+          (when bg-color
+            (send dc set-brush bg-color 'solid)
+            (send dc set-pen bg-color 1 'transparent)
+            (let-values ([(w h) (get-client-size)])
+              (send dc draw-rectangle 0 0 w h)))
           (send dc draw-bitmap icon 
                 (- (/ cw 2) (/ (send icon get-width) 2))
                 (- (/ ch 2) (/ (send icon get-height) 2))

collects/mrlib/scribblings/close-icon.scrbl

@@ -13,8 +13,11 @@ provides a clickable close button icon.}
 @defclass[close-icon% canvas% ()]{
  @defconstructor[([parent (is-a? area-container<%>)]
                   [callback (-> any) void]
+                  [bg-color (or/c #f string (is-a?/c color%))]
                   [horizontal-pad positive-integer? 4]
                   [vertical-pad positive-integer? 4])]{
    The @scheme[callback] is called when the close icon is clicked.
+       
+   If @scheme[bg-color] is specified, it is used as the background color of the icon.
  }
 }