Add button for creating new mod presets

osu.Game/Overlays/Mods/AddPresetButton.cs

@@ -0,0 +1,38 @@
+// 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.Game.Graphics;
+using osu.Game.Graphics.UserInterface;
+using osuTK;
+
+namespace osu.Game.Overlays.Mods
+{
+    public class AddPresetButton : ShearedToggleButton
+    {
+        [Resolved]
+        private OsuColour colours { get; set; } = null!;
+
+        public AddPresetButton()
+            : base(1)
+        {
+            RelativeSizeAxes = Axes.X;
+            Height = ModSelectPanel.HEIGHT;
+
+            // shear will be applied at a higher level in `ModPresetColumn`.
+            Content.Shear = Vector2.Zero;
+            Padding = new MarginPadding();
+
+            Text = "+";
+            TextSize = 30;
+        }
+
+        protected override void UpdateActiveState()
+        {
+            DarkerColour = Active.Value ? colours.Orange1 : ColourProvider.Background3;
+            LighterColour = Active.Value ? colours.Orange0 : ColourProvider.Background1;
+            TextColour = Active.Value ? ColourProvider.Background6 : ColourProvider.Content1;
+        }
+    }
+}