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<HTML><HEAD><TITLE>Xlib Programming Manual: VisibilityNotify Events</TITLE></HEAD><BODY><H1 ALIGN=center>10.10.10 VisibilityNotify Events</H1><!.IN "Events" "VisibilityNotify"><!.IN "VisibilityNotify" "" "@DEF@">The X server can report<B>VisibilityNotify</B>events to clients wanting any change in the visibility of the specified window.A region of a window is visible if someone looking at the screen canactually see it.The X server generates this event whenever the visibility changes state. However, this event is never generated for windows whose class is<B><A HREF="../../window/create.html#InputClass">InputOnly</A></B> .<P>All <B>VisibilityNotify</B>events caused by a hierarchy change are generatedafter any hierarchy event(<B><A HREF="unmap.html">UnmapNotify</A></B>,<B><A HREF="map.html">MapNotify</A></B>, <B><A HREF="configure.html">ConfigureNotify</A></B> ,<B><A HREF="gravity.html">GravityNotify</A></B> ,<B><A HREF="circulate.html">CirculateNotify</A></B>)caused by that change. Any<B>VisibilityNotify</B>event on a given window is generated before any<B><A HREF="../exposure/expose.html">Expose</A></B> events on that window, but it is not required that all<B>VisibilityNotify</B>events on all windows be generated before all <B><A HREF="../exposure/expose.html">Expose</A></B>events on all windows. The X protocol does not constrain the ordering of <B>VisibilityNotify</B>events withrespect to <B><A HREF="../input-focus/">FocusOut</A></B>,<B><A HREF="../window-entry-exit/">EnterNotify</A></B>,and <B><A HREF="../window-entry-exit/">LeaveNotify</A></B>events.<P>To receive <B>VisibilityNotify</B>events, set the<B>VisibilityChangeMask</B>bit in the <A HREF="../../window/attributes/event-and-do-not-propagate.html">event-mask</A> attribute of the window. <P>The structure for this event type contains:<P><!.IN "XVisibilityEvent" "" "@DEF@"><CODE><PRE>typedef struct { int type; /* VisibiltyNotify */ unsigned long serial; /* # of last request processed by server */ Bool send_event; /* true if this came from a <B><A HREF="../../appendix/a.html#SendEvent">SendEvent</A></B> request */ Display *display; /* Display the event was read from */ Window window; int state;} XVisibilityEvent;</PRE></CODE><P>The window member is set to the window whose visibility state changes.The state member is set to the state of the window's visibility and can be<B>VisibilityUnobscured</B>,<B>VisibilityPartiallyObscured</B>,or<B>VisibilityFullyObscured</B>.The X server ignores all of a window's subwindowswhen determining the visibility state of the window and processes <B>VisibilityNotify</B>events according to the following:<UL><P><LI>When the window changes state from partially obscured, fully obscured,or not viewable to viewable and completely unobscured,the X server generates the event with the state member of the<B>XVisibilityEvent</B>structure set to<B>VisibilityUnobscured</B>.<P><LI>When the window changes state from viewable and completely unobscured or not viewable to viewable and partially obscured,the X server generates the event with the state member of the<B>XVisibilityEvent</B>structure set to<B>VisibilityPartiallyObscured</B>.<P><LI>When the window changes state from viewable and completely unobscured, viewable and partially obscured, or not viewable to viewable and fully obscured,the X server generates the event with the state member of the<B>XVisibilityEvent</B>structure set to<B>VisibilityFullyObscured</B>.</UL><H5 ALIGN=right><I>Next: <A HREF="../structure-control/">Structure Control Events</A></I></H5><HR><ADDRESS><A HREF="http://tronche.com/">Christophe Tronche</A>, <A HREF="mailto:ch.tronche@computer.org">ch.tronche@computer.org</A></ADDRESS></BODY></HTML>⌨️ 快捷键说明
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