Events

XI uses a custom event system because of difficulties with simulating events with the UITK event system. With only using the UITK event system it is difficult to take control of event propagation and dispatching, simulating actions based on custom input, and simulating focus and capture actions with a world-space (non screen-space) UI system. So, a series of “Controllers” were made to dispatch events and execute UI actions without using UITK.

Events are broken down into the following categories:

1. Input Events: created directly from inputs
2. Intermediate Events: additional input types generated from input events
3. Interface Events: created internally within UI elements or manipulators

Input Events

There are two types of input events: (1) CursorEvent and (2) FocalEvent. Cursor events are input events from cursors interacting with a document. FocalEvents are code events from keyboard, that are sent only to the focused document.

Input events can be generated by providing inputs to the XIManager. Call XIManager.AddPointerInput and XIManager.AddKeyInput on Update with input states for any appropriate device.

Inputs can also be simulated by sending custom input events with XIManager.Dispatch functions. This is useful, for example, when creating a custom keyboard that should send code events when virtual buttons are “pushed” or for creating unit tests.

Handling Events

Events are handled in a similar way as UITK. Call RegisterCallback with the approate XIEvent to execute actions when this event is received.

Events Table

Event	Type	Fields	Description
PositionEvent	Input	Vector3 Position	Hovering cursor position
PushEvent	Input	int Button	Cursor button press down
PopEvent	Input	int Button	Cursor button press up
AxixEvent	Input	Vector2 Axis	Cursor axis delta
CodePushEvent	Input	Code Code	Code/key press down
CodePopEvent	Input	Code Code	Code/key push up
EnterEvent	Intermediate	Vector3 Position	Cursor enters element
MotionEvent	Intermediate	Vector3 Position, Vector3 Delta, float Proximity	Cursor moves within element
ExitEvent	Intermediate	Vector3 Position	Cursor leaves element
HoverEnterEvent	Interface	-	First pointer enters element
HoverExitEvent	Interface	-	Last pointer exits element
ExecuteEvent	Interface	int Button	Push and pop while hovering
CodeEvent	Interface	Code Code	Repeated after CodePush and stopped after CodePop or lost of focus
ChangeEvent<T>	Interface	T Previous, T New	Editable field value changed
FocusEvent	Interface	FocusType FocusType	Focusable element gains or loses focus
ScrollEvent	Interface	Vector2 Scroll	Element view has been scrolled / panned