groups and background

Geoff Canyon gcanyon at
Sun Dec 29 04:48:01 EST 2002

On Saturday, December 28, 2002, at 03:15 PM, Dar Scott wrote:

> A group may have its backgroundBehavior property set to true.  Such a 
> group introduces interesting paths on any card it is on.  This group 
> is also placed on new cards under some conditions.  The card/stack 
> property backgroundNames lists all groups with this property set to 
> true for the specified card or stack.

BackgroundNames is a property of a stack, but not of a card.

> Groups may be shared.   "The number of backgrounds (of a stack)" is 
> the number of sharable groups in the stack; shared groups are counted 
> only once.  (The number of backgrounds of a card is 0.)  All groups 
> are sharable except nested groups.  The property groupNames is a card 
> property that lists all sharable groups on the card.  There is no such 
> property for stacks.

Everything here is right. I do think "sharable" is unnecessarily 
confusing the issue for the sake of brevity.

_All_ groups are "sharable," in the sense that they can appear on more 
than one card. Groups contained in other groups appear on whatever 
cards their parent groups appear on. You call them nested groups. I 
think of them as "subgroups," although that term has no official 

By "sharable," you might also be referring to the (more verbose) 
concept of "able to be placed onto a card," which rules out 

> "The number of groups" [of a specified card] is the total number of 
> groups on the card including shared and nested.  The number of groups 
> of a stack is the total number of groups on the current card.  Shared 
> groups are counted just once.


> The expression "group <groupref>" refers to a group on the current or 
> specified card.  The expression "background <groupref> refers to any 
> group in the current or specified stack (including nested groups).  
> The layer number (if used) for the background reference refers to the 
> creation order.



Geoff Canyon
gcanyon at

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