Overriden event function and strange Alt+= key behaviour

mkolenda

I am handling QEvent::KeyPress events in class derived from QLineEdit and everything would be good if not one key.
Alt+= is acting something like compose key in my system. I can insert ȩḑçņ characters and to be honest i have no idea why.
This is how it looks inside event(QEvent* e):

[ 01:50:17 ]: QKeyEvent(KeyRelease, 100125b, 40000000, ""Â¸"", false, 2)  // for alt+=
[ 01:51:18 ]: QKeyEvent(KeyRelease, 100125c, 42000000, ""Ë"", false, 2)  // for alt+shift+=

There are no QEvent::KeyPress events! Besides of that it is somehow inserting ¸¸¸¸¸or ˛˛˛˛ when i hold these keystrokes. I don't want that. That's nasty.

My problem is I really want to handle this keystroke and get nativeScanCode() with '='.
Xev is displaying this as

KeyPress event, serial 40, synthetic NO, window 0x5800001,
    root 0x270, subw 0x0, time 16442476, (-857,169), root:(427,799),
    state 0x90, keycode 21 (keysym 0xfe5b, dead_cedilla), same_screen YES,
    XLookupString gives 2 bytes: (c2 b8) "¸"
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: True

Is this XFilterEvent my obstacle here? What can I do?

SGaist

Hi,

With which version of Qt are you experiencing this ?

mkolenda

@SGaist This is 4.8 but i'm moving code to latest 5 version soon.
It just seems like Qt somehow doesn't handle this event which xev is able to properly detect.

SGaist

IIRC Qt 5.5.0 has a bug handling certain key combination which should be fixed for 5.5.1 If you can, try with this one (you may have to built it by hand though)