Double window: how can we detect the FL_SHOW event without subclassing?

[S ET]

Hello,

I am looking for a way to run some code when an Fl_Double_Window shows itself.

Currently, a custom handle() function in a class derived from Fl_Double_Window does the trick.

A callback on an Fl_Double_Window reacts only to FL_CLOSE and nothing else.

Would that be possible without extending Fl_Double_Window?

Thank you.

[Manolo]

You can use function Fl::event_dispatch() to add a custom event dispatch function

(see https://www.fltk.org/doc-1.4/group__fl__events.html#gafc8bd62d8fdacef87c56ed3a22cdcebc).

This dispatch function will be called at each FLTK event with the event type and the receiving window

as parameters. Therein you can react when the event type is FL_SHOW and the window

is that you're interested in.

But it's so much better to just subclass Fl_Double_WIndow.

[Manolo]

It turns out some platforms don't send the FL_SHOW event for toplevel windows.

The event to track should be FL_FOCUS rather than FL_SHOW.

[S ET]

> But it's so much better to just subclass Fl_Double_WIndow.

Ok, it's straightforward indeed. It's just that I found myself sub-classing more often than with other toolkits and wondered if I got stuck in that spiral while ignoring other available ways.

Thank you very much.