docs/latex/wx/idleevt.tex

   1 \section{\class{wxIdleEvent}}\label{wxidleevent}
   2
   3 This class is used for idle events, which are generated when the system becomes
   4 idle. Note that, unless you do something specifically, the idle events are not
   5 sent if the system remains idle once it has become it, e.g. only a single idle
   6 event will be generated until something else resulting in more normal events
   7 happens and only then is the next idle event sent again. If you need to ensure
   8 a continuous stream of idle events, you can either use
   9 \helpref{RequestMore}{wxidleeventrequestmore} method in your handler or call
  10 \helpref{wxWakeUpIdle}{wxwakeupidle} periodically (for example from timer
  11 event), but note that both of these approaches (and especially the first one)
  12 increase the system load and so should be avoided if possible.
  13
  14 By default, idle events are sent to all windows (and also
  15 \helpref{wxApp}{wxapp}, as usual). If this is causing a significant
  16 overhead in your application, you can call \helpref{wxIdleEvent::SetMode}{wxidleeventsetmode} with
  17 the value wxIDLE\_PROCESS\_SPECIFIED, and set the wxWS\_EX\_PROCESS\_IDLE extra
  18 window style for every window which should receive idle events.
  19
  20 \wxheading{Derived from}
  21
  22 \helpref{wxEvent}{wxevent}\\
  23 \helpref{wxObject}{wxobject}
  24
  25 \wxheading{Include files}
  26
  27 <wx/event.h>
  28
  29 \wxheading{Event table macros}
  30
  31 To process an idle event, use this event handler macro to direct input to a member
  32 function that takes a wxIdleEvent argument.
  33
  34 \twocolwidtha{7cm}
  35 \begin{twocollist}\itemsep=0pt
  36 \twocolitem{{\bf EVT\_IDLE(func)}}{Process a wxEVT\_IDLE event.}
  37 \end{twocollist}%
  38
  39 \wxheading{See also}
  40
  41 \helpref{Event handling overview}{eventhandlingoverview}, \helpref{wxUpdateUIEvent}{wxupdateuievent},
  42 \helpref{wxWindow::OnInternalIdle}{wxwindowoninternalidle}
  43
  44 \latexignore{\rtfignore{\wxheading{Members}}}
  45
  46 \membersection{wxIdleEvent::wxIdleEvent}\label{wxidleeventctor}
  47
  48 \func{}{wxIdleEvent}{\void}
  49
  50 Constructor.
  51
  52 \membersection{wxIdleEvent::CanSend}\label{wxidleeventcansend}
  53
  54 \func{static bool}{CanSend}{\param{wxWindow*}{ window}}
  55
  56 Returns {\tt true} if it is appropriate to send idle events to
  57 this window.
  58
  59 This function looks at the mode used (see \helpref{wxIdleEvent::SetMode}{wxidleeventsetmode}),
  60 and the wxWS\_EX\_PROCESS\_IDLE style in {\it window} to determine whether idle events should be sent to
  61 this window now. By default this will always return {\tt true} because
  62 the update mode is initially wxIDLE\_PROCESS\_ALL. You can change the mode
  63 to only send idle events to windows with the wxWS\_EX\_PROCESS\_IDLE extra window style set.
  64
  65 \wxheading{See also}
  66
  67 \helpref{wxIdleEvent::SetMode}{wxidleeventsetmode}
  68
  69 \membersection{wxIdleEvent::GetMode}\label{wxidleeventgetmode}
  70
  71 \func{static wxIdleMode}{GetMode}{\void}
  72
  73 Static function returning a value specifying how wxWidgets
  74 will send idle events: to all windows, or only to those which specify that they
  75 will process the events.
  76
  77 See \helpref{wxIdleEvent::SetMode}{wxidleeventsetmode}.
  78
  79 \membersection{wxIdleEvent::RequestMore}\label{wxidleeventrequestmore}
  80
  81 \func{void}{RequestMore}{\param{bool}{ needMore = true}}
  82
  83 Tells wxWidgets that more processing is required. This function can be called by an OnIdle
  84 handler for a window or window event handler to indicate that wxApp::OnIdle should
  85 forward the OnIdle event once more to the application windows. If no window calls this function
  86 during OnIdle, then the application will remain in a passive event loop (not calling OnIdle) until a
  87 new event is posted to the application by the windowing system.
  88
  89 \wxheading{See also}
  90
  91 \helpref{wxIdleEvent::MoreRequested}{wxidleeventmorerequested}
  92
  93 \membersection{wxIdleEvent::MoreRequested}\label{wxidleeventmorerequested}
  94
  95 \constfunc{bool}{MoreRequested}{\void}
  96
  97 Returns true if the OnIdle function processing this event requested more processing time.
  98
  99 \wxheading{See also}
 100
 101 \helpref{wxIdleEvent::RequestMore}{wxidleeventrequestmore}
 102
 103 \membersection{wxIdleEvent::SetMode}\label{wxidleeventsetmode}
 104
 105 \func{static void}{SetMode}{\param{wxIdleMode }{mode}}
 106
 107 Static function for specifying how wxWidgets will send idle events: to
 108 all windows, or only to those which specify that they
 109 will process the events.
 110
 111 {\it mode} can be one of the following values.
 112 The default is wxIDLE\_PROCESS\_ALL.
 113
 114 \begin{verbatim}
 115 enum wxIdleMode
 116 {
 117         // Send idle events to all windows
 118     wxIDLE_PROCESS_ALL,
 119
 120         // Send idle events to windows that have
 121         // the wxWS_EX_PROCESS_IDLE flag specified
 122     wxIDLE_PROCESS_SPECIFIED
 123 };
 124 \end{verbatim}
 125