diff options
Diffstat (limited to 'src/Fl_Window.cxx')
| -rw-r--r-- | src/Fl_Window.cxx | 38 |
1 files changed, 26 insertions, 12 deletions
diff --git a/src/Fl_Window.cxx b/src/Fl_Window.cxx index 9119b7620..b4d3c621f 100644 --- a/src/Fl_Window.cxx +++ b/src/Fl_Window.cxx @@ -402,28 +402,42 @@ void Fl_Window::free_icons() { } /** - Waits for the window to be fully displayed after calling show(). + Waits for the window to be displayed after calling show(). Fl_Window::show() is not guaranteed to show and draw the window on all platforms immediately. Instead this is done in the background; - particularly on X11 this will take a few messages (client server - roundtrips) to display the window. - - Usually this small delay doesn't matter, but in some cases you may - want to have the window instantiated and displayed synchronously. + particularly on X11 it will take a few messages (client server + roundtrips) to display the window. Usually this small delay doesn't + matter, but in some cases you may want to have the window instantiated + and displayed synchronously. Currently (as of FLTK 1.3.3) this method only has an effect on X11. On Windows and Mac OS X show() is always synchronous. If you want to write portable code and need this synchronous show() feature, add - win->wait_for_expose() on all platforms, FLTK will just do the + win->wait_for_expose() on all platforms, and FLTK will just do the right thing. This method can be used for displaying splash screens before calling Fl::run() or for having exact control over which window - has focus after calling show(). + has the focus after calling show(). If the window is not shown(), this method does nothing. + \note Depending on the platform and window manager wait_for_expose() + may not guarantee that the window is fully drawn when it is called. + Under X11 it may only make sure that the window is \b mapped, i.e. + the internal (OS dependent) window object was created (and maybe + shown on the desktop as an empty frame or something like that). + You may need to call Fl::flush() after wait_for_expose() to make + sure the window and all its widgets are drawn and thus visible. + + \note FLTK does the best it can do to make sure that all widgets + get drawn if you call wait_for_expose() and Fl::flush(). However, + dependent on the window manager it can not be guaranteed that this + does always happen synchronously. The only guaranteed behavior that + all widgets are eventually drawn is if the FLTK event loop is run + continuously, for instance with Fl::run(). + \see virtual void Fl_Window::show() Example code for displaying a window before calling Fl::run() @@ -433,13 +447,13 @@ void Fl_Window::free_icons() { // do more window initialization here ... - win->show(); // show window - win->wait_for_expose(); // wait, until displayed - Fl::flush(); // make sure everything gets drawn + win->show(); // show window + win->wait_for_expose(); // wait, until displayed + Fl::flush(); // make sure everything gets drawn // do more initialization work that needs some time here ... - Fl::run(); // start FLTK event loop + Fl::run(); // start FLTK event loop \endcode Note that the window will not be responsive until the event loop |