Add colourPicker step drawable

osu.Framework.Tests/Visual/Testing/TestSceneStepButton.cs

@@ -59,6 +59,7 @@ namespace osu.Framework.Tests.Visual.Testing
                         CallStack = new StackTrace()
                     },
                     new StepSlider<int>(nameof(StepSlider<int>), 0, 10, 5),
+                    new StepColourPicker(nameof(StepColourPicker), Colour4.AliceBlue),
                 }
             };
         }

osu.Framework/Testing/Drawables/Steps/StepColourPicker.cs

@@ -0,0 +1,69 @@
+// 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;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.UserInterface;
+using osuTK;
+
+namespace osu.Framework.Testing.Drawables.Steps
+{
+    public partial class StepColourPicker : CompositeDrawable
+    {
+        private const float scale_adjust = 0.5f;
+
+        public Action<Colour4>? ValueChanged { get; set; }
+
+        private readonly Bindable<Colour4> current;
+
+        public StepColourPicker(string description, Colour4 initialColour)
+        {
+            current = new Bindable<Colour4>(initialColour);
+
+            RelativeSizeAxes = Axes.X;
+            AutoSizeAxes = Axes.Y;
+
+            InternalChildren = new Drawable[]
+            {
+                new Box
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Colour = FrameworkColour.GreenDark,
+                },
+                new FillFlowContainer
+                {
+                    RelativeSizeAxes = Axes.X,
+                    AutoSizeAxes = Axes.Y,
+                    Direction = FillDirection.Vertical,
+                    Children = new Drawable[]
+                    {
+                        new SpriteText
+                        {
+                            Text = description,
+                            Padding = new MarginPadding(5),
+                            Font = FrameworkFont.Regular.With(size: 14),
+                        },
+                        new BasicColourPicker
+                        {
+                            RelativeSizeAxes = Axes.X,
+                            Width = 1f / scale_adjust,
+                            Scale = new Vector2(scale_adjust),
+                            Current = current,
+                        }
+                    }
+                }
+            };
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            current.BindValueChanged(v => ValueChanged?.Invoke(v.NewValue), true);
+        }
+    }
+}