PointerEventData.delta

Description

Pointer delta since last update.

The delta vector provides the 2D location as the user moves the pointer. It is updated every frame. The 2D location starts at Vector2(0.0f, 0.0f) when OnBeginDrag is called. As OnDrag is called the delta is updated. The value of delta can change greatly.

In the example below deltaValue will start at zero. OnDrag will change the value of dataValue as delta changes.

// Display deltaValue.  This is changed by the delta passed into OnDrag.

using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class ExampleScript : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
    private float timeCount;
    private Vector2 deltaValue = Vector2.zero;

    public void OnBeginDrag(PointerEventData data)
    {
        deltaValue = Vector2.zero;
    }

    public void OnDrag(PointerEventData data)
    {
        deltaValue += data.delta;
        if (data.dragging)
        {
            timeCount += Time.deltaTime;
            if (timeCount > 0.5f)
            {
                timeCount = 0.0f;
                Debug.Log("delta: " + deltaValue);
            }
        }
    }

    public void OnEndDrag(PointerEventData data)
    {
        deltaValue = Vector2.zero;
    }
}