Add double-click-nub-to-reset function to form slider bars

See ppy#35742 (comment).

Author: bdach

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

@@ -1,20 +1,24 @@
 // 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.Linq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Testing;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Graphics.UserInterfaceV2;
 using osu.Game.Overlays;
 using osuTK;
+using osuTK.Input;
 
 namespace osu.Game.Tests.Visual.UserInterface
 {
-    public partial class TestSceneFormSliderBar : OsuTestScene
+    public partial class TestSceneFormSliderBar : OsuManualInputManagerTestScene
     {
         [Cached]
         private OverlayColourProvider colourProvider = new OverlayColourProvider(OverlayColourScheme.Aquamarine);
@@ -59,5 +63,49 @@ public void TestTransferValueOnCommit()
                     slider.TransferValueOnCommit = b;
             });
         }
+
+        [Test]
+        public void TestNubDoubleClickRevertToDefault()
+        {
+            FormSliderBar<float> slider = null!;
+
+            AddStep("create content", () =>
+            {
+                Child = new FillFlowContainer
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    Width = 0.5f,
+                    Direction = FillDirection.Vertical,
+                    Spacing = new Vector2(10),
+                    Children = new Drawable[]
+                    {
+                        slider = new FormSliderBar<float>
+                        {
+                            Caption = "Slider",
+                            Current = new BindableFloat
+                            {
+                                MinValue = 0,
+                                MaxValue = 10,
+                                Precision = 0.1f,
+                                Default = 5f,
+                            }
+                        },
+                    }
+                };
+            });
+            AddStep("set slider to 1", () => slider.Current.Value = 1);
+
+            AddStep("move mouse to nub", () => InputManager.MoveMouseTo(slider.ChildrenOfType<Circle>().Single()));
+
+            AddStep("double click nub", () =>
+            {
+                InputManager.Click(MouseButton.Left);
+                InputManager.Click(MouseButton.Left);
+            });
+
+            AddAssert("slider is default", () => slider.Current.IsDefault);
+        }
     }
 }

osu.Game/Graphics/UserInterfaceV2/FormSliderBar.cs

@@ -324,8 +324,8 @@ private partial class InnerSlider : OsuSliderBar<T>
 
             private Box leftBox = null!;
             private Box rightBox = null!;
-            private Circle nub = null!;
-            private const float nub_width = 10;
+            private InnerSliderNub nub = null!;
+            public const float NUB_WIDTH = 10;
 
             [Resolved]
             private OverlayColourProvider colourProvider { get; set; } = null!;
@@ -335,7 +335,7 @@ private void load()
             {
                 Height = 40;
                 RelativeSizeAxes = Axes.X;
-                RangePadding = nub_width / 2;
+                RangePadding = NUB_WIDTH / 2;
 
                 Children = new Drawable[]
                 {
@@ -364,12 +364,13 @@ private void load()
                     {
                         RelativeSizeAxes = Axes.Both,
                         Padding = new MarginPadding { Horizontal = RangePadding, },
-                        Child = nub = new Circle
+                        Child = nub = new InnerSliderNub
                         {
-                            Width = nub_width,
-                            RelativeSizeAxes = Axes.Y,
-                            RelativePositionAxes = Axes.X,
-                            Origin = Anchor.TopCentre,
+                            ResetToDefault = () =>
+                            {
+                                if (!Current.Disabled)
+                                    Current.SetDefault();
+                            }
                         }
                     },
                     new HoverClickSounds()
@@ -452,5 +453,27 @@ protected override bool Commit()
                 return result;
             }
         }
+
+        private partial class InnerSliderNub : Circle
+        {
+            public Action? ResetToDefault { get; set; }
+
+            [BackgroundDependencyLoader]
+            private void load()
+            {
+                Width = InnerSlider.NUB_WIDTH;
+                RelativeSizeAxes = Axes.Y;
+                RelativePositionAxes = Axes.X;
+                Origin = Anchor.TopCentre;
+            }
+
+            protected override bool OnClick(ClickEvent e) => true; // must be handled for double click handler to ever fire
+
+            protected override bool OnDoubleClick(DoubleClickEvent e)
+            {
+                ResetToDefault?.Invoke();
+                return true;
+            }
+        }
     }
 }