The concepts of <#433#><B>mapped</B><#433#><A ID="434"><tex2html_anchor_invisible_mark></A>, <#435#><B>viewable</B><#435#><A ID="436"><tex2html_anchor_invisible_mark></A>, and
<#437#><B>visible</B><#437#><A ID="438"><tex2html_anchor_invisible_mark></A> apply to any <#439#><TT>xlib:window</TT><#439#> object and therefore
to contacts as well[#x-protocol#<tex2html_cite_mark>#1##<tex2html_cite_mark>#].
A contact is said to be ``mapped'' if <#441#><TT>(xlib:map-window
contact)</TT><#441#> has been called. A contact is ``viewable'' if it and all of its
ancestors are mapped. A contact is ``visible'' only if someone looking at the
display screen can actually see some part of it; that is, the contact is
viewable and is not completely occluded by any other windows.
<A ID="442"><tex2html_anchor_invisible_mark></A>
<A ID="443"><tex2html_anchor_invisible_mark></A>
<A ID="444"><tex2html_anchor_invisible_mark></A>
<P>
</LI>
<LI><#445#><B>Geometry management</B><#445#>: A contact under geometry management control is
CLUE calls the <#463#><TT>update-state</TT><#463#> function
<A ID="464"><tex2html_anchor_invisible_mark></A> in
order to force consistency of the state of all contacts belonging to a <#465#><TT>contact-display</TT><#465#> (see Section~<A HREF=<tex2html_cr_mark>#ch:contact-display#466><tex2html_cr_mark></A>).
The default <#488#><TT>state</TT><#488#> value is <#489#><TT>:mapped</TT><#489#>. As a result, unless
specified otherwise, all contacts will automatically be viewable after
<#490#><TT>update-state</TT><#490#> is called (in particular, after a call to <#491#><TT>process-next-event</TT><#491#>). After initialization and realization,
the <#492#><TT>(setf contact-state)</TT><#492#> accessor method causes transitions in a contact's
state and its visible effect. The most common usages are setting a contact's
state to <#493#><TT>:withdrawn</TT><#493#> to withdraw it or to <#494#><TT>:mapped</TT><#494#> to present it.