GUIの横幅をマウスのドラッグで変更する

DragReSizeFiled.cs

using UnityEngine;
using UnityEditor;
using System.Collections;
using System.Collections.Generic;

public class DragReSizeFiled : EditorWindow {
	
	// Add menu item to the Window menu
	[MenuItem("Window/DragReSizeFiled")]
	static void Init () {
		// Get existing open window or if none, make a new one:
		EditorWindow.GetWindow<DragReSizeFiled>(false, "DragReSizeFiled");
	}




	static Vector2 scrollPosition;

	private int m_focusedControlCounter = 0;
	private Dictionary<Rect, int> cellNumRect = new Dictionary<Rect, int>();
	private List<Rect> controlRects = new List<Rect>();
	private int focusedControl = -1;


	int resizeGroup1Width = 300;
	int resizeGroup2Width = 100;

	// Implement your own editor GUI here.
	void OnGUI () {
		controlRects.Clear();
		cellNumRect.Clear();


		m_focusedControlCounter = 0;
		EditorGUILayout.LabelField("Resize sample" );

		Rect offset = GUILayoutUtility.GetLastRect();
		scrollPosition = GUILayout.BeginScrollView(scrollPosition, false, false);


		bool isDragArea = false;
		bool isDragArea2 = false;
		Rect r ;

		for (int count = 0; count < 5; ++count)
		{

			GUILayout.BeginHorizontal();

			EditorGUILayout.TextField(("unity3d text field resize gourp1 " + count), GUILayout.Width(resizeGroup1Width));
			AddControlRect(offset);


			// TextFieldの間を選択したか +++++++++++++++++++++++++++++++++++++
			if (focusedControl == m_focusedControlCounter)
				isDragArea = true;

			EditorGUILayout.LabelField(" ", GUILayout.Width(3));

			r = AddControlRect(offset);
			EditorGUIUtility.AddCursorRect(r, MouseCursor.ResizeHorizontal);
			// TextFieldの間を選択したか +++++++++++++++++++++++++++++++++++++


			EditorGUILayout.TextField("abcdefg");
			AddControlRect(offset);


			GUILayout.EndHorizontal();
		}



		for (int count = 0; count < 5; ++count)
		{

			GUILayout.BeginHorizontal();

			EditorGUILayout.LabelField(("unity3d text field resize gourp2 " + count), GUILayout.Width(resizeGroup2Width));
			AddControlRect(offset);


			// TextFieldの間を選択したか +++++++++++++++++++++++++++++++++++++
			if (focusedControl == m_focusedControlCounter)
				isDragArea2 = true;

			EditorGUILayout.LabelField(" ", GUILayout.Width(3));

			r = AddControlRect(offset);
			EditorGUIUtility.AddCursorRect(r, MouseCursor.ResizeHorizontal);
			// TextFieldの間を選択したか +++++++++++++++++++++++++++++++++++++


			EditorGUILayout.TextField("abcdefg");
			AddControlRect(offset);


			GUILayout.EndHorizontal();
		}





		GUILayout.EndScrollView();

		Event ev = Event.current;
		if (ev.type == EventType.mouseUp)
		{
			m_focusedControlCounter = -1;
			focusedControl = -1;
			Event.current.Use();
			Repaint();
		}
		else if (ev.type == EventType.mouseDown)
		{
			m_mousDownPosition = ev.mousePosition;
			focusedControl = GetControlNum(ev.mousePosition);
			Event.current.Use();
			Repaint();
		}
		else if (ev.type == EventType.mouseDrag)
		{
			if (isDragArea)
			{
				int diff = (int)(ev.mousePosition.x - m_mousDownPosition.x);
				m_mousDownPosition = ev.mousePosition;
				resizeGroup1Width = (resizeGroup1Width + diff);
				Repaint();
			}
			else if (isDragArea2)
			{
				int diff = (int)(ev.mousePosition.x - m_mousDownPosition.x);
				m_mousDownPosition = ev.mousePosition;
				resizeGroup2Width = (resizeGroup2Width + diff);
				Repaint();
			}
		}

	}



	Vector2 m_mousDownPosition = Vector2.zero;

	private Rect AddControlRect(Rect offset)
	{
		Rect r = GUILayoutUtility.GetLastRect();
		Rect res = r;
		r.y += offset.y + offset.height;
		controlRects.Add(r);
		cellNumRect[r] = m_focusedControlCounter++;
		return res;
	}

	private int GetControlNum(Vector2 pos)
	{
		pos += scrollPosition;
		int i = 0;
		foreach (Rect r in controlRects)
		{
			if (r.Contains(pos)) return i;
			++i;
		}
		return -1;
	}


}