API reference

Events and input

Events are dispatched as in a browser: capture, target, bubble, default actions. The event classes are in DevCore.UiEngine.Input.

Listening

In a component

<div class="slot" onpointerdown={e => Grab(e)} onpointerup={e => Drop(e)}></div>

From game code

using DevCore.UiEngine.Dom.Events;
using DevCore.UiEngine.Input;

button.AddEventListener(EventType.Click, e => StartGame());

Event objects are pooled: an event is valid only while its handler runs. Copy the values you need; do not keep the object.

Event types

Group	Events
Pointer	`pointerdown`, `pointermove`, `pointerup`, `pointercancel`, `pointerover`, `pointerout`, `pointerenter`, `pointerleave`, `gotpointercapture`, `lostpointercapture`
Mouse	`click`, `dblclick`, `contextmenu`, `auxclick`, `wheel`, and the mouse events
Keyboard	`keydown`, `keyup`
Focus	`focus`, `blur`, `focusin`, `focusout`
Text	`beforeinput`, `input`, `change`, and the composition events
Gamepad	`cancel` (B or Circle)

PointerEvent

Member	Meaning
`int PointerId`	Which pointer. The mouse is 1
`PointerType PointerType`	Mouse, touch or pen
`bool IsPrimary`	Whether it is the main pointer of its type
`float ClientX`, `ClientY`	The position in the view, in CSS pixels
`int Button`	The button that changed: 0 main, 1 middle, 2 secondary
`int Buttons`	The buttons held, as bits
`int Detail`	The click count
`KeyModifiers Modifiers`, `ShiftKey`…	The modifier keys held
`Element RelatedTarget`	For over, out, enter and leave: the other element
`CurrentTarget`, `Target`	The element whose listener runs; the element the event is for
`PreventDefault()`, `StopPropagation()`	As in a browser

KeyboardEvent and WheelEvent

Member	Meaning
`KeyboardEvent.Key`	The key's value: `"a"`, `"Enter"`, `"ArrowLeft"`
`KeyboardEvent.Code`	The physical key: `"KeyA"`
`KeyboardEvent.Modifiers`, `Repeat`	Modifier keys; whether it is an auto-repeat
`WheelEvent.DeltaX`, `DeltaY`	The scroll amount
`WheelEvent.ClientX`, `ClientY`, `Modifiers`	Where, and with which keys

Pointer capture and focus

Extension methods on Element:

Member	Meaning
`bool SetPointerCapture(int pointerId)`	Sends that pointer's events to this element. Only a pointer with a button down can be captured
`void ReleasePointerCapture(int pointerId)`	Ends it. It also ends by itself after the last button's `pointerup`, and on cancel
`bool HasPointerCapture(int pointerId)`	Whether this element holds the pointer
`bool Focus()`, `void Blur()`	Moves focus to the element; removes it

A captured element gets the events even if it has pointer-events: none.

Input from code

view.View.Input is the page's DocumentInput. Use it for tests, tutorials, replays and custom devices.

var input = view.View.Input;

input.PointerMove(PointerInput.Mouse(120, 80));
input.PointerDown(PointerInput.Mouse(120, 80));
input.PointerUp(PointerInput.Mouse(120, 80));          // a click at (120, 80)

input.KeyDown("Enter");
input.KeyUp("Enter");
input.TextInput("hello");

input.Navigate(NavigationDirection.Down);              // as the d-pad does
input.Confirm();                                       // as A does
input.Cancel();                                        // as B does

Member	Meaning
`PointerMove`, `PointerDown`, `PointerUp(in PointerInput input)`	Pointer input at a position
`PointerCancel(int pointerId)`, `PointerExit(int pointerId)`	The pointer was cancelled; it left the view
`Wheel(in PointerInput input, float deltaX, float deltaY)`	A wheel turn
`KeyDown(string key, string code = null, KeyModifiers modifiers = None, bool repeat = false)`, `KeyUp`	Keys
`TextInput(string \| char \| ReadOnlySpan<char>)`	Typed text for the focused control
`CompositionUpdate`, `CompositionCommit`	IME composition
`bool Focus(Element element)`, `Blur()`, `bool MoveFocus(bool forward = true)`	Focus, and Tab or Shift+Tab
`bool Navigate(NavigationDirection direction)`	Spatial navigation: `Up`, `Right`, `Down`, `Left`
`Confirm()`, `bool Cancel()`	Activate the focused element; send `cancel`
`bool ScrollBy(float deltaX, float deltaY)`	Scroll what is under focus or the pointer
`Element HoveredElement(int pointerId = 1)`	What a pointer is over
`bool ArrowKeysNavigate`	Whether arrow keys move focus like the d-pad

PointerInput.Mouse(float x, float y, int button = 0, double time = 0, KeyModifiers modifiers = None) makes the input of a mouse; new PointerInput(id, PointerType.Touch, x, y) that of another pointer.

Did the UI take the mouse?

using DevCore.UiEngine.Unity.Hosting;

if (UiSystem.Input.TryGetMouseView(out UIView view, out Vector2 position))
    return;     // the pointer is over a page: do not shoot, do not move the camera