Unity Project

reference
https://cardgames.io/yahtzee/

Library/PackageCache/com.unity.timeline@1.2.15/Editor/Items/ItemsGroup.cs

@@ -0,0 +1,63 @@
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    class ItemsGroup
+    {
+        readonly ITimelineItem[] m_Items;
+        readonly ITimelineItem m_LeftMostItem;
+        readonly ITimelineItem m_RightMostItem;
+
+        public ITimelineItem[] items
+        {
+            get { return m_Items; }
+        }
+
+        public double start
+        {
+            get { return m_LeftMostItem.start; }
+            set
+            {
+                var offset = value - m_LeftMostItem.start;
+
+                foreach (var clip in m_Items)
+                    clip.start += offset;
+            }
+        }
+
+        public double end
+        {
+            get { return m_RightMostItem.end; }
+        }
+
+        public ITimelineItem leftMostItem
+        {
+            get { return m_LeftMostItem;  }
+        }
+
+        public ITimelineItem rightMostItem
+        {
+            get { return m_RightMostItem; }
+        }
+
+        public ItemsGroup(IEnumerable<ITimelineItem> items)
+        {
+            Debug.Assert(items != null && items.Any());
+
+            m_Items = items.ToArray();
+            m_LeftMostItem = null;
+            m_RightMostItem = null;
+
+            foreach (var item in m_Items)
+            {
+                if (m_LeftMostItem == null || item.start < m_LeftMostItem.start)
+                    m_LeftMostItem = item;
+
+                if (m_RightMostItem == null || item.end > m_RightMostItem.end)
+                    m_RightMostItem = item;
+            }
+        }
+    }
+}