Initial Commit

Library/PackageCache/com.unity.timeline@1.5.4/Editor/Window/PlaybackScroller.cs

@@ -0,0 +1,67 @@
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    /// <summary>
+    /// Scrolling mode during playback for the timeline window.
+    /// </summary>
+    public enum PlaybackScrollMode
+    {
+        /// <summary>
+        /// Timeline window doesn't change while the playhead is leaving the window.
+        /// </summary>
+        None,
+        /// <summary>
+        /// Timeline window pans its content when the playhead arrive at the right of the window (like a paging scrolling).
+        /// </summary>
+        Pan,
+        /// <summary>
+        /// Timeline window move the content as the playhead moves.
+        /// When the playhead reach the middle of the window, it stays there and the content scroll behind it.
+        /// </summary>
+        Smooth
+    }
+
+    static class PlaybackScroller
+    {
+        public static void AutoScroll(WindowState state)
+        {
+            if (Event.current.type != EventType.Layout)
+                return;
+
+            switch (state.autoScrollMode)
+            {
+                case PlaybackScrollMode.Pan:
+                    DoPanScroll(state);
+                    break;
+                case PlaybackScrollMode.Smooth:
+                    DoSmoothScroll(state);
+                    break;
+            }
+        }
+
+        static void DoSmoothScroll(WindowState state)
+        {
+            if (state.playing)
+                state.SetPlayHeadToMiddle();
+
+            state.UpdateLastFrameTime();
+        }
+
+        static void DoPanScroll(WindowState state)
+        {
+            if (!state.playing)
+                return;
+
+            var paddingDeltaTime = state.PixelDeltaToDeltaTime(WindowConstants.autoPanPaddingInPixels);
+            var showRange = state.timeAreaShownRange;
+            var rightBoundForPan = showRange.y - paddingDeltaTime;
+            if (state.editSequence.time > rightBoundForPan)
+            {
+                var leftBoundForPan = showRange.x + paddingDeltaTime;
+                var delta = rightBoundForPan - leftBoundForPan;
+                state.SetTimeAreaShownRange(showRange.x + delta, showRange.y + delta);
+            }
+        }
+    }
+}