53 lines
1.7 KiB
Plaintext
53 lines
1.7 KiB
Plaintext
Keyboard notifier
|
|
|
|
One can use register_keyboard_notifier to get called back on keyboard
|
|
events (see kbd_keycode() function for details). The passed structure is
|
|
keyboard_notifier_param:
|
|
|
|
- 'vc' always provide the VC for which the keyboard event applies;
|
|
- 'down' is 1 for a key press event, 0 for a key release;
|
|
- 'shift' is the current modifier state, mask bit indexes are KG_*;
|
|
- 'value' depends on the type of event.
|
|
|
|
- KBD_KEYCODE events are always sent before other events, value is the keycode.
|
|
- KBD_UNBOUND_KEYCODE events are sent if the keycode is not bound to a keysym.
|
|
value is the keycode.
|
|
- KBD_UNICODE events are sent if the keycode -> keysym translation produced a
|
|
unicode character. value is the unicode value.
|
|
- KBD_KEYSYM events are sent if the keycode -> keysym translation produced a
|
|
non-unicode character. value is the keysym.
|
|
- KBD_POST_KEYSYM events are sent after the treatment of non-unicode keysyms.
|
|
That permits one to inspect the resulting LEDs for instance.
|
|
|
|
For each kind of event but the last, the callback may return NOTIFY_STOP in
|
|
order to "eat" the event: the notify loop is stopped and the keyboard event is
|
|
dropped.
|
|
|
|
In a rough C snippet, we have:
|
|
|
|
kbd_keycode(keycode) {
|
|
...
|
|
params.value = keycode;
|
|
if (notifier_call_chain(KBD_KEYCODE,¶ms) == NOTIFY_STOP)
|
|
|| !bound) {
|
|
notifier_call_chain(KBD_UNBOUND_KEYCODE,¶ms);
|
|
return;
|
|
}
|
|
|
|
if (unicode) {
|
|
param.value = unicode;
|
|
if (notifier_call_chain(KBD_UNICODE,¶ms) == NOTIFY_STOP)
|
|
return;
|
|
emit unicode;
|
|
return;
|
|
}
|
|
|
|
params.value = keysym;
|
|
if (notifier_call_chain(KBD_KEYSYM,¶ms) == NOTIFY_STOP)
|
|
return;
|
|
apply keysym;
|
|
notifier_call_chain(KBD_POST_KEYSYM,¶ms);
|
|
}
|
|
|
|
NOTE: This notifier is usually called from interrupt context.
|