ElectronBot/3.Software/Unity/ElectronBot-Studio/Assets/Packages/UI Widgets/Scripts/ScrollRectUtilities/ScrollRectRestrictedDrag.cs

namespace UIWidgets
{
	using UnityEngine;
	using UnityEngine.EventSystems;
	using UnityEngine.UI;

	/// <summary>
	/// Restrict drag in ScrollRect.
	/// </summary>
	public class ScrollRectRestrictedDrag : ScrollRect
	{
		/// <summary>
		/// Max drag positions.
		/// </summary>
		public Vector2 MaxDrag = Vector2.zero;

		/// <summary>
		/// Start position.
		/// </summary>
		protected Vector2 CursorStartPosition = Vector2.zero;

		/// <summary>
		/// Handle begin drag event.
		/// </summary>
		/// <param name="eventData">Event data.</param>
		public override void OnBeginDrag(PointerEventData eventData)
		{
			if (eventData.button != PointerEventData.InputButton.Left)
			{
				return;
			}

			if (!IsActive())
			{
				return;
			}

			CursorStartPosition = Vector2.zero;
			RectTransformUtility.ScreenPointToLocalPointInRectangle(viewRect, eventData.position, eventData.pressEventCamera, out CursorStartPosition);

			base.OnBeginDrag(eventData);
		}

		/// <summary>
		/// Handle drag event.
		/// </summary>
		/// <param name="eventData">Event data.</param>
		public override void OnDrag(PointerEventData eventData)
		{
			if (eventData.button != PointerEventData.InputButton.Left)
			{
				return;
			}

			if (!IsActive())
			{
				return;
			}

			Vector2 localCursor;
			if (!RectTransformUtility.ScreenPointToLocalPointInRectangle(viewRect, eventData.position, eventData.pressEventCamera, out localCursor))
			{
				return;
			}

			if (MaxDrag != Vector2.zero)
			{
				var pointerDelta = localCursor - CursorStartPosition;
				var delta = Vector2.zero;

				if ((MaxDrag.x > 0f) && (Mathf.Abs(pointerDelta.x) > MaxDrag.x) && horizontal)
				{
					delta.x = pointerDelta.x > 0 ? MaxDrag.x - pointerDelta.x : -(MaxDrag.x + pointerDelta.x);
				}

				if ((MaxDrag.y > 0f) && (Mathf.Abs(pointerDelta.y) > MaxDrag.y) && vertical)
				{
					delta.y = pointerDelta.y > 0 ? MaxDrag.y - pointerDelta.y : -(MaxDrag.y + pointerDelta.y);
				}

				Vector3 source_point;
				RectTransformUtility.ScreenPointToWorldPointInRectangle(viewRect, eventData.position, eventData.pressEventCamera, out source_point);

				var result_point = new Vector3(source_point.x + delta.x, source_point.y + delta.y);
				eventData.position = RectTransformUtility.WorldToScreenPoint(eventData.pressEventCamera, result_point);
			}

			base.OnDrag(eventData);
		}
	}
}