mirrors/fltk
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Clarify documentation of Fl_Window::wait_for_expose().

Browse Source 
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10635 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
This commit is contained in:
Albrecht Schlosser 2015-03-17 16:13:52 +00:00
parent ae4b51b970
commit bbdfa06f78
1 changed files with 26 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
src/Fl_Window.cxx
View File

@ -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