> > The question: what is the correct way to fire a graphics update from > a thread ?
> Others will probably chime in and tell you more about programming with > threads and FLTK. Ah... That quite possibly means me then... OK, at a high level, it goes something like this: Firstly, a caveat: Rendering to the display device from any thread other than the "main" thread is not robust (may work on some systems, will fail in horrible, hard to debug ways, on others, so do not do that.) Instead, all drawing is done from the "main" thread. In particular, note that creating/deleting/hiding/showing windows *has* to be done by the "main" thread. However, if you create your widgets in the "main" thread, you can alter them from other threads quite safely, if you use the fltk locking methods. You can signal updates between threads using Fl::awake(); there's no need to get fancy with pipe's and so forth (fltk is handling that internally) and it is more portable. Here's a simple recipe for this: - in the "main" thread, before you create any windows, call Fl::lock(); *just once* to enable thread support. (Do not do any more locking/unlocking in the main thread, let fltk manage that for you.) - in a worker thread, if you want to update a widget, do: Fl::lock(); my_widget->change_this(); my_other_widget->change_that(value); etc.; Fl::unlock(); Fl::awake(); And that should update the widgets in a thread-safe way, then flag the main thread to manage the redraw sequence. Note that Fl::awake can also be passed a callback function - the "main" thread will then execute that callback in its context, allowing the worker threads to do some operations that would not otherwise be allowed (e.g. you may be able to use this to create new windows under the control of a child thread, since the actual creation will occur in the context of the "main" thread.) However, that is often not necessary, the simple case I outlined above covers a lot of use cases. Selex ES Ltd Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL A company registered in England & Wales. Company no. 02426132 ******************************************************************** This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. ******************************************************************** _______________________________________________ fltk mailing list fltk@easysw.com http://lists.easysw.com/mailman/listinfo/fltk
