unity ui shadow box gallery

ShadowBG.cs

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class ShadowBG : MonoBehaviour
{

	protected Image image;
	public float fadeTime = 2.0f;
	protected float currentTime = 0.0f;
	protected float alphaTarget = 0.0f;
	public AnimationCurve showCurve = AnimationCurve.Linear (0, 0, 1, 1);
	public AnimationCurve hideCurve = AnimationCurve.Linear (0, 0, 1, 1);
	protected Image shownImage = null;
	protected RectTransform origin;
	protected bool visible = false;
	protected Vector3 originalPosition;
	protected Vector2 originalSizeDelta;
	protected Vector3 originalScale;
	protected Vector2 originalAnchorMin;
	protected Vector2 originalAnchorMax;
	protected bool transitioning = false;


	public bool Visible {
		get {
			return visible;
		}
	}
	// Use this for initialization

	public void Awake ()
	{
		image = GetComponent<Image> ();

	}

	void Start ()
	{
	
	}
	
	// Update is called once per frame
	void Update ()
	{
		if (transitioning) {
			currentTime += Time.deltaTime * 1.0f / fadeTime;
			currentTime = Mathf.Clamp01 (currentTime);
			float t = 0;
			float a = 0;
			Vector3 scale = Vector3.one;
			Vector3 position = Vector3.zero;
			Vector2 sizeDelta = Vector2.zero;
			Vector2 anchorMin = Vector2.zero;
			Vector2 anchorMax = Vector2.zero;
			if (visible) {
				t = showCurve.Evaluate (currentTime);
				a = Mathf.Lerp (image.color.a, alphaTarget, t);
				scale = Vector3.Lerp (shownImage.rectTransform.localScale, Vector3.one, t);
				position = Vector3.Lerp (shownImage.rectTransform.localPosition, Vector3.zero, t);
				sizeDelta = Vector2.Lerp (shownImage.rectTransform.sizeDelta, Vector2.one, t);
				anchorMin = Vector2.Lerp (shownImage.rectTransform.anchorMin, Vector2.zero, t);
				anchorMax = Vector2.Lerp (shownImage.rectTransform.anchorMax, Vector2.one, t);
			} else {
				t = hideCurve.Evaluate (currentTime);
				a = Mathf.Lerp (image.color.a, alphaTarget, t);
				scale = Vector3.Lerp (shownImage.rectTransform.localScale, originalScale, t);
				position = Vector3.Lerp (shownImage.rectTransform.localPosition, originalPosition, t);
				sizeDelta = Vector2.Lerp (shownImage.rectTransform.sizeDelta, originalSizeDelta, t);
				anchorMin = Vector2.Lerp (shownImage.rectTransform.anchorMin, originalAnchorMin, t);
				anchorMax = Vector2.Lerp (shownImage.rectTransform.anchorMax, originalAnchorMax, t);

			}
			image.color = new Color (image.color.r, image.color.g, image.color.b, a);
			shownImage.rectTransform.localScale = scale;
			shownImage.rectTransform.localPosition = position;
			shownImage.rectTransform.sizeDelta = sizeDelta;
			shownImage.rectTransform.anchorMin = anchorMin;
			shownImage.rectTransform.anchorMax = anchorMax;
		}
	}

	public void show (Image showImage, RectTransform origin)
	{
		this.shownImage = showImage;
		this.origin = origin;
		shownImage.rectTransform.SetParent (this.image.rectTransform);
		originalPosition = shownImage.rectTransform.localPosition;
		originalScale = shownImage.rectTransform.localScale;
		originalSizeDelta = shownImage.rectTransform.sizeDelta;
		originalAnchorMax = shownImage.rectTransform.anchorMax;
		originalAnchorMin = shownImage.rectTransform.anchorMin;
		visible = true;
		alphaTarget = 1.0f;
		transitioning = true;
		currentTime = 0;
	}

	public void hide ()
	{
		visible = false;
		alphaTarget = 0;
		transitioning = true;
		currentTime = 0;
	}
}