Add omission of pages when there are too many

osu.Game.Tests/Visual/UserInterface/TestScenePageSelector.cs

@@ -35,14 +35,24 @@ namespace osu.Game.Tests.Visual.UserInterface
         {
             setAvailablePages(100);
 
-            AddAssert("Correct page buttons", () => pageSelector.ChildrenOfType<PageSelectorPageButton>().Select(p => p.PageNumber).SequenceEqual(new[] { 1, 2, 3, 100 }));
+            selectPageIndex(0);
+            checkVisiblePageNumbers(new[] { 1, 2, 3, 100 });
+
+            selectPageIndex(6);
+            checkVisiblePageNumbers(new[] { 1, 5, 6, 7, 8, 9, 100 });
+
+            selectPageIndex(49);
+            checkVisiblePageNumbers(new[] { 1, 48, 49, 50, 51, 52, 100 });
+
+            selectPageIndex(99);
+            checkVisiblePageNumbers(new[] { 1, 98, 99, 100 });
         }
 
         [Test]
         public void TestResetCurrentPage()
         {
             setAvailablePages(10);
-            selectPage(6);
+            selectPageIndex(6);
             setAvailablePages(11);
             AddAssert("Page 1 is current", () => pageSelector.CurrentPage.Value == 0);
         }
@@ -51,14 +61,16 @@ namespace osu.Game.Tests.Visual.UserInterface
         public void TestOutOfBoundsSelection()
         {
             setAvailablePages(10);
-            selectPage(11);
+            selectPageIndex(11);
             AddAssert("Page 10 is current", () => pageSelector.CurrentPage.Value == pageSelector.AvailablePages.Value - 1);
 
-            selectPage(-1);
+            selectPageIndex(-1);
             AddAssert("Page 1 is current", () => pageSelector.CurrentPage.Value == 0);
         }
 
-        private void selectPage(int pageIndex) =>
+        private void checkVisiblePageNumbers(int[] expected) => AddAssert($"Sequence is {string.Join(',', expected.Select(i => i.ToString()))}", () => pageSelector.ChildrenOfType<PageSelectorPageButton>().Select(p => p.PageNumber).SequenceEqual(expected));
+
+        private void selectPageIndex(int pageIndex) =>
             AddStep($"Select page {pageIndex}", () => pageSelector.CurrentPage.Value = pageIndex);
 
         private void setAvailablePages(int availablePages) =>

osu.Game/Graphics/UserInterface/PageSelector/PageEllipsis.cs

@@ -0,0 +1,33 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Overlays;
+
+namespace osu.Game.Graphics.UserInterface.PageSelector
+{
+    internal class PageEllipsis : CompositeDrawable
+    {
+        [BackgroundDependencyLoader]
+        private void load(OverlayColourProvider colourProvider)
+        {
+            RelativeSizeAxes = Axes.Y;
+            AutoSizeAxes = Axes.X;
+
+            InternalChildren = new Drawable[]
+            {
+                new OsuSpriteText
+                {
+                    Font = OsuFont.GetFont(size: 12, weight: FontWeight.SemiBold),
+                    Text = "...",
+                    Colour = colourProvider.Light3,
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                }
+            };
+        }
+    }
+}

osu.Game/Graphics/UserInterface/PageSelector/PageSelector.cs

@@ -1,7 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System.Linq;
+using System;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics;
 using osu.Framework.Bindables;
@@ -50,43 +50,47 @@ namespace osu.Game.Graphics.UserInterface.PageSelector
         {
             base.LoadComplete();
 
-            CurrentPage.BindValueChanged(onCurrentPageChanged);
+            CurrentPage.BindValueChanged(_ => redraw());
             AvailablePages.BindValueChanged(_ => redraw(), true);
         }
 
-        private void onCurrentPageChanged(ValueChangedEvent<int> currentPage)
+        private void redraw()
         {
-            if (currentPage.NewValue >= AvailablePages.Value)
+            if (CurrentPage.Value >= AvailablePages.Value)
             {
                 CurrentPage.Value = AvailablePages.Value - 1;
                 return;
             }
 
-            foreach (var page in itemsFlow.OfType<PageSelectorPageButton>())
+            previousPageButton.Enabled.Value = CurrentPage.Value != 0;
-                page.Selected = page.PageNumber == currentPage.NewValue + 1;
+            nextPageButton.Enabled.Value = CurrentPage.Value < AvailablePages.Value - 1;
 
-            previousPageButton.Enabled.Value = currentPage.NewValue != 0;
-            nextPageButton.Enabled.Value = currentPage.NewValue < AvailablePages.Value - 1;
-        }
-
-        private void redraw()
-        {
             itemsFlow.Clear();
 
-            for (int i = 0; i < AvailablePages.Value; i++)
+            int totalPages = AvailablePages.Value;
+            bool lastWasEllipsis = false;
+
+            for (int i = 0; i < totalPages; i++)
             {
                 int pageIndex = i;
 
+                bool shouldShowPage = pageIndex == 0 || pageIndex == totalPages - 1 || Math.Abs(pageIndex - CurrentPage.Value) <= 2;
+
+                if (shouldShowPage)
+                {
+                    lastWasEllipsis = false;
                     itemsFlow.Add(new PageSelectorPageButton(pageIndex + 1)
                     {
                         Action = () => CurrentPage.Value = pageIndex,
+                        Selected = CurrentPage.Value == pageIndex,
                     });
                 }
-
+                else if (!lastWasEllipsis)
-            if (CurrentPage.Value != 0)
+                {
-                CurrentPage.Value = 0;
+                    lastWasEllipsis = true;
-            else
+                    itemsFlow.Add(new PageEllipsis());
-                CurrentPage.TriggerChange();
+                }
+            }
         }
     }
 }