Merge pull request #16647 from peppy/song-select-scroll-position-during-delete

Ensure beatmap carousel scroll position is maintained during deletion operations

osu.Game.Tests/Visual/SongSelect/TestSceneBeatmapCarousel.cs

@@ -9,6 +9,7 @@ using osu.Framework.Allocation;
 using osu.Framework.Extensions.IEnumerableExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Framework.Utils;
 using osu.Game.Beatmaps;
 using osu.Game.Configuration;
 using osu.Game.Rulesets;
@@ -40,6 +41,36 @@ namespace osu.Game.Tests.Visual.SongSelect
             this.rulesets = rulesets;
         }
 
+        [Test]
+        public void TestScrollPositionMaintainedOnAdd()
+        {
+            loadBeatmaps(count: 1, randomDifficulties: false);
+
+            for (int i = 0; i < 10; i++)
+            {
+                AddRepeatStep("Add some sets", () => carousel.UpdateBeatmapSet(TestResources.CreateTestBeatmapSetInfo()), 4);
+
+                checkSelectionIsCentered();
+            }
+        }
+
+        [Test]
+        public void TestScrollPositionMaintainedOnDelete()
+        {
+            loadBeatmaps(count: 50, randomDifficulties: false);
+
+            for (int i = 0; i < 10; i++)
+            {
+                AddRepeatStep("Remove some sets", () =>
+                    carousel.RemoveBeatmapSet(carousel.Items.Select(item => item.Item)
+                                                      .OfType<CarouselBeatmapSet>()
+                                                      .OrderBy(item => item.GetHashCode())
+                                                      .First(item => item.State.Value != CarouselItemState.Selected && item.Visible).BeatmapSet), 4);
+
+                checkSelectionIsCentered();
+            }
+        }
+
         [Test]
         public void TestManyPanels()
         {
@@ -813,6 +844,18 @@ namespace osu.Game.Tests.Visual.SongSelect
                 carousel.Items.Count(s => (diff ? s.Item is CarouselBeatmap : s.Item is CarouselBeatmapSet) && s.Item.Visible) == count);
         }
 
+        private void checkSelectionIsCentered()
+        {
+            AddAssert("Selected panel is centered", () =>
+            {
+                return Precision.AlmostEquals(
+                    carousel.ScreenSpaceDrawQuad.Centre,
+                    carousel.Items
+                            .First(i => i.Item.State.Value == CarouselItemState.Selected)
+                            .ScreenSpaceDrawQuad.Centre, 100);
+            });
+        }
+
         private void checkNoSelection() => AddAssert("Selection is null", () => currentSelection == null);
 
         private void nextRandom() =>

osu.Game/Screens/Select/BeatmapCarousel.cs

@@ -286,6 +286,9 @@ namespace osu.Game.Screens.Select
 
             root.RemoveChild(existingSet);
             itemsCache.Invalidate();
+
+            if (!Scroll.UserScrolling)
+                ScrollToSelected(true);
         });
 
         public void UpdateBeatmapSet(BeatmapSetInfo beatmapSet) => Schedule(() =>
@@ -311,13 +314,10 @@ namespace osu.Game.Screens.Select
 
             itemsCache.Invalidate();
 
-            Schedule(() =>
+            if (!Scroll.UserScrolling)
-            {
+                ScrollToSelected(true);
-                if (!Scroll.UserScrolling)
-                    ScrollToSelected(true);
 
-                BeatmapSetsChanged?.Invoke();
+            BeatmapSetsChanged?.Invoke();
-            });
         });
 
         /// <summary>