RectTransformのAnchorをオブジェクトのサイズに合わせるエディタ拡張

RectTransformExtention.cs

using UnityEngine;
using UnityEditor;

using System.Collections;
using System.Linq;

public static class RectTransformExtention
{
	[MenuItem("Util/RectTransform/Fit Anchors #t")]
	static void FitAnchorsToTransform()
	{
		var rectTransforms = from gameObject in Selection.gameObjects
		                     where gameObject.GetComponent<RectTransform>() != null
		                     select gameObject.GetComponent<RectTransform>();

		if (rectTransforms == null || rectTransforms.Count() <= 0)
		{
			Debug.Log("No RectTransform is selected.");
			return;
		}

		Undo.RecordObjects(rectTransforms.ToArray(), "Fit Anchors");

		foreach (var item in rectTransforms)
		{
			FitAnchorsToTransform(item);
		}
	}

	static void FitAnchorsToTransform(RectTransform rectTransform)
	{
		var parent = rectTransform.parent as RectTransform;
		if (parent == null) { return; }

		// 親のピボットを原点とした座標系での値

		var leftPos = rectTransform.localPosition.x + rectTransform.rect.x;
		var rightPos = leftPos + rectTransform.rect.width;
		var bottomPos = rectTransform.localPosition.y + rectTransform.rect.y;
		var topPos = bottomPos + rectTransform.rect.height;

		var parentWidth = parent.rect.width;
		var parentHeight = parent.rect.height;
		var parentLeftPos = parent.rect.x;
		var parentBottomPos = parent.rect.y;

		var xMin = (leftPos - parentLeftPos) / parentWidth;
		var xMax = (rightPos - parentLeftPos) / parentWidth;

		var yMin = (bottomPos - parentBottomPos) / parentHeight;
		var yMax = (topPos - parentBottomPos) / parentHeight;

		// アンカーを設定
		rectTransform.anchorMin = new Vector2(xMin, yMin);
		rectTransform.anchorMax = new Vector2(xMax, yMax);

		// アンカーからの距離はゼロに設定
		rectTransform.offsetMin = Vector2.zero;
		rectTransform.offsetMax = Vector2.zero;
	}
}