From 028c958431728deb42811a92a3993f2382ee49a6 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Fri, 20 Sep 2019 19:19:43 +0900
Subject: [PATCH] Initial implementation of a switch button

---
 .../UserInterface/TestSceneSwitchButton.cs    |  20 +++
 .../Graphics/UserInterface/SwitchButton.cs    | 117 ++++++++++++++++++
 2 files changed, 137 insertions(+)
 create mode 100644 osu.Game.Tests/Visual/UserInterface/TestSceneSwitchButton.cs
 create mode 100644 osu.Game/Graphics/UserInterface/SwitchButton.cs

diff --git a/osu.Game.Tests/Visual/UserInterface/TestSceneSwitchButton.cs b/osu.Game.Tests/Visual/UserInterface/TestSceneSwitchButton.cs
new file mode 100644
index 0000000000..8fe381f141
--- /dev/null
+++ b/osu.Game.Tests/Visual/UserInterface/TestSceneSwitchButton.cs
@@ -0,0 +1,20 @@
+// 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.Graphics;
+using osu.Game.Graphics.UserInterface;
+
+namespace osu.Game.Tests.Visual.UserInterface
+{
+    public class TestSceneSwitchButton : OsuTestScene
+    {
+        public TestSceneSwitchButton()
+        {
+            Child = new SwitchButton
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+            };
+        }
+    }
+}
diff --git a/osu.Game/Graphics/UserInterface/SwitchButton.cs b/osu.Game/Graphics/UserInterface/SwitchButton.cs
new file mode 100644
index 0000000000..21712051ef
--- /dev/null
+++ b/osu.Game/Graphics/UserInterface/SwitchButton.cs
@@ -0,0 +1,117 @@
+// 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.Extensions.Color4Extensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Colour;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Input.Events;
+using osuTK;
+using osuTK.Graphics;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    public class SwitchButton : Checkbox
+    {
+        private const float border_thickness = 4.5f;
+        private const float padding = 1.25f;
+
+        private readonly Box fill;
+        private readonly Container switchContainer;
+        private readonly Drawable switchCircle;
+        private readonly CircularBorderContainer circularContainer;
+
+        private Color4 enabledColour;
+        private Color4 disabledColour;
+
+        public SwitchButton()
+        {
+            Size = new Vector2(45, 20);
+
+            InternalChild = circularContainer = new CircularBorderContainer
+            {
+                RelativeSizeAxes = Axes.Both,
+                BorderColour = Color4.White,
+                BorderThickness = border_thickness,
+                Masking = true,
+                Children = new Drawable[]
+                {
+                    fill = new Box
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        AlwaysPresent = true,
+                        Alpha = 0
+                    },
+                    new Container
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        Padding = new MarginPadding(border_thickness + padding),
+                        Child = switchContainer = new Container
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                            Child = switchCircle = new CircularContainer
+                            {
+                                RelativeSizeAxes = Axes.Both,
+                                FillMode = FillMode.Fit,
+                                Masking = true,
+                                Child = new Box { RelativeSizeAxes = Axes.Both }
+                            }
+                        }
+                    }
+                }
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            enabledColour = colours.BlueDark;
+            disabledColour = colours.Gray3;
+
+            switchContainer.Colour = enabledColour;
+            fill.Colour = disabledColour;
+
+            updateBorder();
+        }
+
+        protected override void OnUserChange(bool value)
+        {
+            base.OnUserChange(value);
+
+            if (value)
+                switchCircle.MoveToX(switchContainer.DrawWidth - switchCircle.DrawWidth, 200, Easing.OutQuint);
+            else
+                switchCircle.MoveToX(0, 200, Easing.OutQuint);
+
+            fill.FadeTo(value ? 1 : 0, 250, Easing.OutQuint);
+
+            updateBorder();
+        }
+
+        protected override bool OnHover(HoverEvent e)
+        {
+            updateBorder();
+            return base.OnHover(e);
+        }
+
+        protected override void OnHoverLost(HoverLostEvent e)
+        {
+            updateBorder();
+            base.OnHoverLost(e);
+        }
+
+        private void updateBorder()
+        {
+            circularContainer.TransformBorderTo((Current.Value ? enabledColour : disabledColour).Lighten(IsHovered ? 0.3f : 0));
+        }
+
+        private class CircularBorderContainer : CircularContainer
+        {
+            public void TransformBorderTo(SRGBColour colour)
+                => this.TransformTo(nameof(BorderColour), colour, 250, Easing.OutQuint);
+        }
+    }
+}