Use double in ScrollContainer for scroll tracking

osu.Framework.Tests/Visual/Containers/TestSceneScrollContainer.cs

@@ -525,7 +525,7 @@ private void scrollTo(float position, float scrollContentHeight, float extension
             AddStep($"scroll to {position}", () =>
             {
                 scrollContainer.ScrollTo(position, false);
-                immediateScrollPosition = scrollContainer.Current;
+                immediateScrollPosition = (float)scrollContainer.Current;
             });
 
             AddAssert($"immediately scrolled to {clampedTarget}", () => Precision.AlmostEquals(clampedTarget, immediateScrollPosition, 1));

osu.Framework.Tests/Visual/Containers/TestSceneScrollContainerDoublePrecision.cs

@@ -0,0 +1,149 @@
+// Copyright (c) ppy Pty Ltd <[email protected]>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Diagnostics;
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Testing;
+using osu.Framework.Utils;
+using osuTK;
+using osuTK.Graphics;
+
+namespace osu.Framework.Tests.Visual.Containers
+{
+    public partial class TestSceneScrollContainerDoublePrecision : ManualInputManagerTestScene
+    {
+        private const float item_height = 5000;
+        private const int item_count = 8000;
+
+        private ScrollContainer<Drawable> scrollContainer = null!;
+
+        [SetUp]
+        public void Setup() => Schedule(Clear);
+
+        [Test]
+        public void TestStandard()
+        {
+            AddStep("Create scroll container", () =>
+            {
+                Add(scrollContainer = new BasicScrollContainer
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    ScrollbarVisible = true,
+                    RelativeSizeAxes = Axes.Both,
+                    Size = new Vector2(0.7f, 0.9f),
+                });
+
+                for (int i = 0; i < item_count; i++)
+                {
+                    scrollContainer.Add(new BoxWithDouble
+                    {
+                        Colour = new Color4(RNG.NextSingle(1), RNG.NextSingle(1), RNG.NextSingle(1), 1),
+                        RelativeSizeAxes = Axes.X,
+                        Height = item_height,
+                        Y = i * item_height,
+                    });
+                }
+            });
+
+            scrollIntoView(item_count - 2);
+            scrollIntoView(item_count - 1);
+        }
+
+        [Test]
+        public void TestDoublePrecision()
+        {
+            AddStep("Create scroll container", () =>
+            {
+                Add(scrollContainer = new DoubleScrollContainer
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    ScrollbarVisible = true,
+                    RelativeSizeAxes = Axes.Both,
+                    Size = new Vector2(0.7f, 0.9f),
+                });
+
+                for (int i = 0; i < item_count; i++)
+                {
+                    scrollContainer.Add(new BoxWithDouble
+                    {
+                        Colour = new Color4(RNG.NextSingle(1), RNG.NextSingle(1), RNG.NextSingle(1), 1),
+                        RelativeSizeAxes = Axes.X,
+                        Height = item_height,
+                        DoubleLocation = i * item_height,
+                    });
+                }
+            });
+
+            scrollIntoView(item_count - 2);
+            scrollIntoView(item_count - 1);
+        }
+
+        private void scrollIntoView(int index)
+        {
+            AddStep($"scroll {index} into view", () => scrollContainer.ScrollIntoView(scrollContainer.ChildrenOfType<BoxWithDouble>().Skip(index).First()));
+            AddUntilStep($"{index} is visible", () => !scrollContainer.ChildrenOfType<BoxWithDouble>().Skip(index).First().IsMaskedAway);
+        }
+
+        public partial class DoubleScrollContainer : BasicScrollContainer
+        {
+            private readonly Container<BoxWithDouble> layoutContent;
+
+            public override void Add(Drawable drawable)
+            {
+                if (drawable is not BoxWithDouble boxWithDouble)
+                    throw new InvalidOperationException();
+
+                Add(boxWithDouble);
+            }
+
+            public void Add(BoxWithDouble drawable)
+            {
+                if (drawable is not BoxWithDouble boxWithDouble)
+                    throw new InvalidOperationException();
+
+                layoutContent.Height = (float)Math.Max(layoutContent.Height, boxWithDouble.DoubleLocation + boxWithDouble.DrawHeight);
+                layoutContent.Add(drawable);
+            }
+
+            public DoubleScrollContainer()
+            {
+                // Managing our own custom layout within ScrollContent causes feedback with internal ScrollContainer calculations,
+                // so we must maintain one level of separation from ScrollContent.
+                base.Add(layoutContent = new Container<BoxWithDouble>
+                {
+                    RelativeSizeAxes = Axes.X,
+                });
+            }
+
+            public override double GetChildPosInContent(Drawable d, Vector2 offset)
+            {
+                if (d is not BoxWithDouble boxWithDouble)
+                    return base.GetChildPosInContent(d, offset);
+
+                return boxWithDouble.DoubleLocation + offset.X;
+            }
+
+            protected override void ApplyCurrentToContent()
+            {
+                Debug.Assert(ScrollDirection == Direction.Vertical);
+
+                double scrollableExtent = -Current + ScrollableExtent * ScrollContent.RelativeAnchorPosition.Y;
+
+                foreach (var d in layoutContent)
+                    d.Y = (float)(d.DoubleLocation + scrollableExtent);
+            }
+        }
+
+        public partial class BoxWithDouble : Box
+        {
+            public double DoubleLocation { get; set; }
+        }
+    }
+}

osu.Framework.Tests/Visual/UserInterface/TestSceneRearrangeableListContainer.cs

@@ -467,7 +467,7 @@ private BasicRearrangeableListItem<int>.Button getDragger(int index)
 
         private partial class TestRearrangeableList : BasicRearrangeableListContainer<int>
         {
-            public float ScrollPosition => ScrollContainer.Current;
+            public float ScrollPosition => (float)ScrollContainer.Current;
 
             public new IReadOnlyDictionary<int, RearrangeableListItem<int>> ItemMap => base.ItemMap;
 

osu.Framework/Graphics/Containers/ScrollContainer.cs

@@ -118,35 +118,35 @@ public bool ScrollbarOverlapsContent
         /// <summary>
         /// The current scroll position.
         /// </summary>
-        public float Current { get; private set; }
+        public double Current { get; private set; }
 
         /// <summary>
         /// The target scroll position which is exponentially approached by current via a rate of distance decay.
         /// </summary>
         /// <remarks>
         /// When not animating scroll position, this will always be equal to <see cref="Current"/>.
         /// </remarks>
-        public float Target { get; private set; }
+        public double Target { get; private set; }
 
         /// <summary>
         /// The maximum distance that can be scrolled in the scroll direction.
         /// </summary>
-        public float ScrollableExtent => Math.Max(AvailableContent - DisplayableContent, 0);
+        public double ScrollableExtent => Math.Max(AvailableContent - DisplayableContent, 0);
 
         /// <summary>
         /// The maximum distance that the scrollbar can move in the scroll direction.
         /// </summary>
         /// <remarks>
         /// May not be accurate to actual display of scrollbar if <see cref="ToScrollbarPosition"/> or <see cref="FromScrollbarPosition"/> are overridden.
         /// </remarks>
-        protected float ScrollbarMovementExtent => Math.Max(DisplayableContent - Scrollbar.DrawSize[ScrollDim], 0);
+        protected double ScrollbarMovementExtent => Math.Max(DisplayableContent - Scrollbar.DrawSize[ScrollDim], 0);
 
         /// <summary>
         /// Clamp a value to the available scroll range.
         /// </summary>
         /// <param name="position">The value to clamp.</param>
         /// <param name="extension">An extension value beyond the normal extent.</param>
-        protected float Clamp(float position, float extension = 0) => Math.Max(Math.Min(position, ScrollableExtent + extension), -extension);
+        protected double Clamp(double position, double extension = 0) => Math.Max(Math.Min(position, ScrollableExtent + extension), -extension);
 
         protected override Container<T> Content => ScrollContent;
 
@@ -345,8 +345,8 @@ protected override void OnDrag(DragEvent e)
 
             Vector2 childDelta = ToLocalSpace(e.ScreenSpaceMousePosition) - ToLocalSpace(e.ScreenSpaceLastMousePosition);
 
-            float scrollOffset = -childDelta[ScrollDim];
-            float clampedScrollOffset = Clamp(Target + scrollOffset) - Clamp(Target);
+            double scrollOffset = -childDelta[ScrollDim];
+            double clampedScrollOffset = Clamp(Target + scrollOffset) - Clamp(Target);
 
             // If we are dragging past the extent of the scrollable area, half the offset
             // such that the user can feel it.
@@ -424,7 +424,7 @@ public void OffsetScrollPosition(float offset)
             Current += offset;
         }
 
-        private void scrollByOffset(float value, bool animated, double distanceDecay = float.PositiveInfinity) =>
+        private void scrollByOffset(double value, bool animated, double distanceDecay = float.PositiveInfinity) =>
             OnUserScroll(Target + value, animated, distanceDecay);
 
         /// <summary>
@@ -454,15 +454,15 @@ public void ScrollToEnd(bool animated = true, bool allowDuringDrag = false)
         /// </summary>
         /// <param name="offset">The amount by which we should scroll.</param>
         /// <param name="animated">Whether to animate the movement.</param>
-        public void ScrollBy(float offset, bool animated = true) => scrollTo(Target + offset, animated);
+        public void ScrollBy(double offset, bool animated = true) => scrollTo(Target + offset, animated);
 
         /// <summary>
         /// Handle a scroll to an absolute position from a user input.
         /// </summary>
         /// <param name="value">The position to scroll to.</param>
         /// <param name="animated">Whether to animate the movement.</param>
         /// <param name="distanceDecay">Controls the rate with which the target position is approached after jumping to a specific location. Default is <see cref="DistanceDecayJump"/>.</param>
-        protected virtual void OnUserScroll(float value, bool animated = true, double? distanceDecay = null) =>
+        protected virtual void OnUserScroll(double value, bool animated = true, double? distanceDecay = null) =>
             ScrollTo(value, animated, distanceDecay);
 
         /// <summary>
@@ -471,9 +471,9 @@ protected virtual void OnUserScroll(float value, bool animated = true, double? d
         /// <param name="value">The position to scroll to.</param>
         /// <param name="animated">Whether to animate the movement.</param>
         /// <param name="distanceDecay">Controls the rate with which the target position is approached after jumping to a specific location. Default is <see cref="DistanceDecayJump"/>.</param>
-        public void ScrollTo(float value, bool animated = true, double? distanceDecay = null) => scrollTo(value, animated, distanceDecay ?? DistanceDecayJump);
+        public void ScrollTo(double value, bool animated = true, double? distanceDecay = null) => scrollTo(value, animated, distanceDecay ?? DistanceDecayJump);
 
-        private void scrollTo(float value, bool animated, double distanceDecay = float.PositiveInfinity)
+        private void scrollTo(double value, bool animated, double distanceDecay = double.PositiveInfinity)
         {
             Target = Clamp(value, ClampExtension);
 
@@ -497,11 +497,11 @@ private void scrollTo(float value, bool animated, double distanceDecay = float.P
         /// <param name="animated">Whether to animate the movement.</param>
         public void ScrollIntoView(Drawable d, bool animated = true)
         {
-            float childPos0 = GetChildPosInContent(d);
-            float childPos1 = GetChildPosInContent(d, d.DrawSize);
+            double childPos0 = GetChildPosInContent(d);
+            double childPos1 = GetChildPosInContent(d, d.DrawSize);
 
-            float minPos = Math.Min(childPos0, childPos1);
-            float maxPos = Math.Max(childPos0, childPos1);
+            double minPos = Math.Min(childPos0, childPos1);
+            double maxPos = Math.Max(childPos0, childPos1);
 
             if (minPos < Current || (minPos > Current && d.DrawSize[ScrollDim] > DisplayableContent))
                 ScrollTo(minPos, animated);
@@ -515,14 +515,14 @@ public void ScrollIntoView(Drawable d, bool animated = true)
         /// <param name="d">The child to get the position from.</param>
         /// <param name="offset">Positional offset in the child's space.</param>
         /// <returns>The position of the child.</returns>
-        public float GetChildPosInContent(Drawable d, Vector2 offset) => d.ToSpaceOfOtherDrawable(offset, ScrollContent)[ScrollDim];
+        public virtual double GetChildPosInContent(Drawable d, Vector2 offset) => d.ToSpaceOfOtherDrawable(offset, ScrollContent)[ScrollDim];
 
         /// <summary>
         /// Determines the position of a child in the content.
         /// </summary>
         /// <param name="d">The child to get the position from.</param>
         /// <returns>The position of the child.</returns>
-        public float GetChildPosInContent(Drawable d) => GetChildPosInContent(d, Vector2.Zero);
+        public double GetChildPosInContent(Drawable d) => GetChildPosInContent(d, Vector2.Zero);
 
         private void updatePosition()
         {
@@ -544,15 +544,15 @@ private void updatePosition()
                     localDistanceDecay = distance_decay_clamping * 2;
 
                 // Lastly, we gradually nudge the target towards valid bounds.
-                Target = (float)Interpolation.Lerp(Clamp(Target), Target, Math.Exp(-distance_decay_clamping * Time.Elapsed));
+                Target = Interpolation.Lerp(Clamp(Target), Target, Math.Exp(-distance_decay_clamping * Time.Elapsed));
 
-                float clampedTarget = Clamp(Target);
+                double clampedTarget = Clamp(Target);
                 if (Precision.AlmostEquals(clampedTarget, Target))
                     Target = clampedTarget;
             }
 
             // Exponential interpolation between the target and our current scroll position.
-            Current = (float)Interpolation.Lerp(Target, Current, Math.Exp(-localDistanceDecay * Time.Elapsed));
+            Current = Interpolation.Lerp(Target, Current, Math.Exp(-localDistanceDecay * Time.Elapsed));
 
             // This prevents us from entering the de-normalized range of floating point numbers when approaching target closely.
             if (Precision.AlmostEquals(Current, Target))
@@ -578,28 +578,40 @@ protected override void UpdateAfterChildren()
             }
 
             if (ScrollDirection == Direction.Horizontal)
-            {
                 Scrollbar.X = ToScrollbarPosition(Current);
-                ScrollContent.X = -Current + ScrollableExtent * ScrollContent.RelativeAnchorPosition.X;
-            }
             else
-            {
                 Scrollbar.Y = ToScrollbarPosition(Current);
-                ScrollContent.Y = -Current + ScrollableExtent * ScrollContent.RelativeAnchorPosition.Y;
-            }
+
+            ApplyCurrentToContent();
+        }
+
+        /// <summary>
+        /// This is the final internal step of updating the scroll container, which takes
+        /// <see cref="Current"/> and applies it to <see cref="ScrollContent"/> in order to
+        /// correctly offset children.
+        ///
+        /// Overriding this method can be used to inhibit this default behaviour, to for instance
+        /// redirect the positioning to another container or change the way it is applied.
+        /// </summary>
+        protected virtual void ApplyCurrentToContent()
+        {
+            if (ScrollDirection == Direction.Horizontal)
+                ScrollContent.X = (float)(-Current + (ScrollableExtent * ScrollContent.RelativeAnchorPosition.X));
+            else
+                ScrollContent.Y = (float)(-Current + (ScrollableExtent * ScrollContent.RelativeAnchorPosition.Y));
         }
 
         /// <summary>
         /// Converts a scroll position to a scrollbar position.
         /// </summary>
         /// <param name="scrollPosition">The absolute scroll position (e.g. <see cref="Current"/>).</param>
         /// <returns>The scrollbar position.</returns>
-        protected virtual float ToScrollbarPosition(float scrollPosition)
+        protected virtual float ToScrollbarPosition(double scrollPosition)
         {
             if (Precision.AlmostEquals(0, ScrollableExtent))
                 return 0;
 
-            return ScrollbarMovementExtent * (scrollPosition / ScrollableExtent);
+            return (float)(ScrollbarMovementExtent * (scrollPosition / ScrollableExtent));
         }
 
         /// <summary>
@@ -612,7 +624,7 @@ protected virtual float FromScrollbarPosition(float scrollbarPosition)
             if (Precision.AlmostEquals(0, ScrollbarMovementExtent))
                 return 0;
 
-            return ScrollableExtent * (scrollbarPosition / ScrollbarMovementExtent);
+            return (float)(ScrollableExtent * (scrollbarPosition / ScrollbarMovementExtent));
         }
 
         /// <summary>