com.unity.uiextensions.nosample/Scripts/Layout/TileSizeFitter.cs

/// Credit ??
/// Sourced from - http://forum.unity3d.com/threads/scripts-useful-4-6-scripts-collection.264161/page-3#post-2280109

using System.Collections;
using UnityEngine.EventSystems;

namespace UnityEngine.UI.Extensions
{
[ExecuteInEditMode]
[RequireComponent(typeof(RectTransform))]
[AddComponentMenu("Layout/Extensions/Tile Size Fitter")]
public class TileSizeFitter : UIBehaviour, ILayoutSelfController
{
	[SerializeField] private Vector2 m_Border = Vector2.zero;
	public Vector2 Border { get { return m_Border; } set { if (SetPropertyUtility.SetStruct(ref m_Border, value)) SetDirty(); } }
	
	[SerializeField] private Vector2 m_TileSize = Vector2.zero;
	public Vector2 TileSize { get { return m_TileSize; } set { if (SetPropertyUtility.SetStruct(ref m_TileSize, value)) SetDirty(); } }

	[System.NonSerialized] private RectTransform m_Rect;
	private RectTransform rectTransform { get { if (m_Rect == null) m_Rect = GetComponent<RectTransform>(); return m_Rect; } }

	private DrivenRectTransformTracker m_Tracker;

	#region Unity Lifetime calls

	protected override void OnEnable()
	{
		base.OnEnable();
		SetDirty();
	}

	protected override void OnDisable()
	{
		m_Tracker.Clear();
		LayoutRebuilder.MarkLayoutForRebuild(rectTransform);
		base.OnDisable();
	}

	#endregion

	protected override void OnRectTransformDimensionsChange()
	{
		UpdateRect();
	}

	private void UpdateRect()
	{
		if (!IsActive())
			return;

		m_Tracker.Clear();

		m_Tracker.Add(this, rectTransform,
			DrivenTransformProperties.Anchors |
			DrivenTransformProperties.AnchoredPosition);
		rectTransform.anchorMin = Vector2.zero;
		rectTransform.anchorMax = Vector2.one;
		rectTransform.anchoredPosition = Vector2.zero;

		m_Tracker.Add(this, rectTransform,
			DrivenTransformProperties.SizeDeltaX |
			DrivenTransformProperties.SizeDeltaY);
		Vector2 sizeDelta = GetParentSize() - Border;
		if (TileSize.x > 0.001f)
			sizeDelta.x -= Mathf.Floor(sizeDelta.x / TileSize.x) * TileSize.x;
		else
			sizeDelta.x = 0;
		if (TileSize.y > 0.001f)
			sizeDelta.y -= Mathf.Floor(sizeDelta.y / TileSize.y) * TileSize.y;
		else
			sizeDelta.y = 0;
		rectTransform.sizeDelta = -sizeDelta;
	}

	private Vector2 GetParentSize()
	{
		RectTransform parent = rectTransform.parent as RectTransform;
		if (!parent)
			return Vector2.zero;
		return parent.rect.size;
	}

	public virtual void SetLayoutHorizontal() { }
	public virtual void SetLayoutVertical() { }

	protected void SetDirty()
	{
		if (!IsActive())
			return;

		UpdateRect();
	}

#if UNITY_EDITOR
	protected override void OnValidate()
	{
		m_TileSize.x = Mathf.Clamp(m_TileSize.x, 0.001f, 1000f);
		m_TileSize.y = Mathf.Clamp(m_TileSize.y, 0.001f, 1000f);
		SetDirty();
	}
#endif
}
}