Handling keys in application

[bellenot]

@LeWhoo

Running example is as always difficult, because the code is big and complicated. But the taks I want to achieve is extremely simple:

OK, so let’s try to solve your issues in a simple way

@LeWhoo

1. Invoke menus and other tasks with keyboard, like mentioned ctrl-s for saving (in my case saving the canvas to a file). This is the function that almost all GUI app have

So simply add AddInput() and use gVirtualX->GrabKey(), like for example with ctrl-s:

yourFrame->AddInput(kKeyPressMask); gVirtualX->GrabKey(yourFrame->GetId(), gVirtualX->KeysymToKeycode(kKey_s), kKeyControlMask, on);

@LeWhoo

2. When I press a keyboard cursor I want to change the Canvas image. However, this needs to work, similar to the ctrl-s example, regardless of where the mouse is - over the canvas, over the frames of the frame, etc. In my current implementation it doesn’t.

You can try to add gVirtualX->SetInputFocus(yourFrame->GetId());in addition to the method described above, but this will work only if the Window Manager allows it, and we cannot prevent other applications to steal the focus… There is not much we can do to change the way the Window Manager control the focus (but you can most probably change your WM settings)

@LeWhoo

I use dispatch, because I just don’t know how to implement it If I understand correctly, the only way to catch the event generated with keyboard after using AddInput() is to connect “ProcessedEvent” to the frame. I think ProcessedEvent is not directly handled by PyROOT, therefore I have to write my own dispatcher in C and call it from Python. In such a case, following an example for some other controls given by wlav, I need to use DispatchVA() to dispatch the event to my PyROOT function.

There are several ways in C++, but I’m afraid I can’t really help on the Python side…

Cheers, Bertrand