Identifier for the event. This is either a name occurring in the
event-type hierarchy @event_tree
or an integer. The latter is used for ASCII-type events and represents
the ASCII value. See also
event<-key.
Whether or not an event is of specified type is normally tested using
event->is_a.
Other useful classifications are realised using
event->is_up, event->is_down, event->is_drag, event->has_modifier, event<-click_time
and
event<-click_displacement.
One event requires special treatment. This is the event related to wheel-mice,
mice normally having two buttons and a scroll-wheel. Rotations of the
scroll-wheel are mapped to an
event object with event<-id:
wheel. Conform the Microsoft windows conventions, this event is has a rotation
attribute, associate using object->attribute.
The rotation has the value 120 if the wheel is rotated from the user and
-120 when rotated towards the user.
In the X11 version, wheel-events are normally mapped to the virtual
mouse-buttons 4 and 5. If the class-variable
event.x11_wheel_mouse = @on
(default in the X11 version), the low-level event handling will map the
button 4 and button 5 events to wheel events.
The wheel event is handled by class window,
class editor, class list_browser
and class scroll_bar.
- See also
- event
->is_a
