Colors :
========

   Every graphic objects have standard foreground and background
colors fixed by resource. The foreground color is used to draw the
boundary of the objects. The background is used to fill the area of
the object. Example of resources for box graphic object :

         atg*boxForeground:       AntiqueWhite4
         atg*boxBackground:       LemonChiffon

   They have specific foreground and background color for hilighting
operation fixed by resources, like :

         atg*hilightBoxForeground: Red
         atg*hilightBoxBackground: Lightgoldenrod


   Label have foreground and background colors fixed by resources
depending of the type of the label (struct, behav, logic or hook) and
of the graphic object they label.

         atg*behavLabelBoxForeground:  HotPink4
         atg*structLabelBoxForeground: SteelBlue4
         atg*logicLabelBoxForeground:  darkgoldenrod4
         atg*hookLabelBoxForeground:   darkgreen


   Object foreground and background color can be changed by menu resp.
<Attributes>:<Foreground> and <Attributes>:<Background> (you can
change color individually or on the selected sets of objects
altogether). These menus are fixed by resources. You give the number
of foreground and background colors you want to appear in the menus
and you give the list of the colors.

   The <Default> button command of the <Foreground> and <Background>>
menu is used to reset the original color on the graphic objects.
   The <Attributes>:<Background>:<Visible On/Off> menu command allows
you to make you graphic objects opaque or transparents. By default,
box are transparent and other objects are opaque.