On 05.03.2008, at 23:23, Alvin wrote: >> Or "gray out" the slider by deactivating it while the >> operation is running, then reactivate it when done. > > This is certainly a possibility but require disabling several controls > ranging from sliders to menu items.
Well, you fund Fl::flush() already, but the clean way to do this is to disable() the controls that you don't want to be changed. This is fairly easy if you either keep a list of controls that need to be disabled, or simply disable the whole window (which automatically disables all widgets inside that window). From a user interface perspective however, I would avaoid triggering a long calculation when the user releases the slider. That would be unexpected and counterproductive since the user may have to adjust multiple sliders, or may want to fine-tune the slider setting. The common solution would be a "Start" Button that opens a modal progress dialog with a "Cancel" button. But if you already call Fl::check() frequently and honor a "Cancel" request, I suggest this, which is a great compromise of both solutions above: Your calculation should be done on a second data set. Whenever the user starts to move a slider, cancel any calculation that may be going on. When the user releases the slider, copy the data from the sliders to the second data set, then restart the calculation immediatly, but keep the sliders active. Whenever the user changes his mind during the calculation, he simply changes the slider setting again, triggering another calculation. You can even add a small progress slider somewhere to indicate that the calculation has started, and how long it will take to finish. That is IMHO the most intuitive solution. Cheers, Matthias ---- http://robowerk.com/ _______________________________________________ fltk mailing list [email protected] http://lists.easysw.com/mailman/listinfo/fltk
