Skip to main content

Input

YAUI uses the EventSystem of Unity for input. Pointer events, selection, navigation with a gamepad or a keyboard, and the Input System UI Input Module all work as they do with uGUI.

Setup​

  1. Add an EventSystem to the scene (GameObject > UI > Event System).
  2. Add YauiRaycaster to the GameObject of each panel that receives input.

YauiRaycaster is a BaseRaycaster, like uGUI's GraphicRaycaster, so YAUI panels and uGUI canvases can receive input in the same scene. Overlay panels are on top of everything rendered by cameras, and are ordered by their SortOrder. World space panels are seen through the panel's EventCamera.

Receiving events​

Events go to the GameObject of the topmost element under the pointer, and bubble up the hierarchy to the first GameObject that handles them, as with uGUI. Implement the usual EventSystem interfaces on a component of an element:

using UnityEngine;
using UnityEngine.EventSystems;
using Yaui;

[RequireComponent(typeof(YauiElement))]
public class HoverHighlight : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler
{
    YauiElement element;

    void Awake() => element = GetComponent<YauiElement>();

    public void OnPointerEnter(PointerEventData eventData) => element.BackgroundColor = Color.yellow;
    public void OnPointerExit(PointerEventData eventData) => element.BackgroundColor = Color.white;
}

For buttons, toggles, sliders and other common widgets, use the controls.

What receives hits​

An element is hit when:

  • RaycastTarget is on (the default), and
  • it draws something: a visible box (background, border or shadow), a text, or an image.

Containers without a visible box never block the pointer, so there is no need to turn off RaycastTarget on layout containers. To make an invisible area receive hits, give it a background color with a very small alpha.

Hits are tested against the transformed box of the element, clipped by the clips of its ancestors. Rotated elements are tested exactly. Hits use the state that was last rendered.

Hit testing uses a uniform grid, built with Burst and updated only where the shapes changed.

Hit testing from scripts​

YauiPanel.HitTest(screenPosition) returns the topmost element that receives hits at a screen position, or null.

var element = panel.HitTest(Input.mousePosition);