Selection Box

A visual indicator that automatically follows selected UI objects via EventSystem

Overview

Selection Box is an animated visual indicator that automatically tracks and highlights the currently selected UI element in your canvas. It responds to Unity's EventSystem selection changes, smoothly animating position, size, fade effects, and appearance with customizable curves and override settings.

The component handles automatic detection of selected objects, smooth animated transitions, fade in/out effects, per-object appearance customization via SelectionBoxOverride, and continuous tracking of moving UI elements.

Usage

Create a UI object in your canvas for the selection box

Add Selection Box component

Configure animation settings:

Animation Duration for movement speed
Animation Curve for easing
Fade Duration for visibility transitions

Set default appearance:

Default Offset for padding around selected objects
Default Sprite for the box visual
Default Color for tinting

Optionally enable Only Override Objects to restrict selection tracking

The selection box will automatically follow EventSystem selection changes

Properties

Animation Settings

Field	Type	Description
`animationDuration`	`float`	Duration of the movement and resize animation
`animationCurve`	`AnimationCurve`	Animation curve for position and size transitions
`fadeDuration`	`float`	Duration of the fade in/out animation

Default Appearance

Field	Type	Description
`defaultOffset`	`Vector2`	Default offset from the selected object's edges
`defaultSprite`	`Sprite`	Default sprite/texture for the selection box
`defaultColor`	`Color`	Default color for the selection box
`pixelsPerUnitMultiplier`	`float`	Pixels per unit multiplier for sliced images

Detection Settings

Field	Type	Description
`onlyOverrideObjects`	`bool`	If true, only objects with SelectionBoxOverride component will be selectable

Public Methods

Name	Parameters	Description
`SelectObject(RectTransform target)`	`RectTransform`	Manually select a UI object and move the selection box to it
`Deselect()`	None	Deselect and hide the selection box
`GetCurrentTarget()`	None	Returns the currently selected RectTransform
`SetOnlyOverrideObjects(bool value)`	`bool`	Set whether to only select objects with SelectionBoxOverride component

Override Component

Add SelectionBoxOverride component to individual UI elements to customize how the selection box appears when they are selected.

Properties

Field	Type	Description
`Offset`	`Vector2`	Custom offset for this object
`OverrideSprite`	`Sprite`	Custom sprite to use when this object is selected
`OverrideColor`	`bool`	Whether to override the color
`Color`	`Color`	Custom color when overriding
`OverridePPU`	`bool`	Whether to override pixels per unit multiplier
`PixelsPerUnitMultiplier`	`float`	Custom PPU multiplier when overriding

Code Example

SelectionBoxExample.cs

using UnityEngine;
using Evo.UI;

public class SelectionBoxExample : MonoBehaviour
{
    public SelectionBox selectionBox;
    public RectTransform customButton;

    void Start()
    {
        // Configure selection box behavior
        selectionBox.SetOnlyOverrideObjects(false);
    }

    public void SelectCustomButton()
    {
        // Manually select a specific UI element
        selectionBox.SelectObject(customButton);
    }

    public void ClearSelection()
    {
        // Hide the selection box
        selectionBox.Deselect();
    }

    public void CheckCurrentSelection()
    {
        // Get the currently selected target
        RectTransform current = selectionBox.GetCurrentTarget();
        
        if (current != null)
        {
            Debug.Log("Currently selected: " + current.name);
        }
        else
        {
            Debug.Log("No object selected");
        }
    }

    void Update()
    {
        // Example: Press Tab to clear selection
        if (Input.GetKeyDown(KeyCode.Tab))
        {
            selectionBox.Deselect();
        }
    }
}

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