add random button

osu.Game/Screens/Select/FooterButton.cs

@@ -54,7 +54,8 @@ namespace osu.Game.Screens.Select
             }
         }
 
-        private readonly SpriteText spriteText;
+        protected readonly Container textContainer;
+        protected readonly SpriteText spriteText;
         private readonly Box box;
         private readonly Box light;
 
@@ -65,7 +66,7 @@ namespace osu.Game.Screens.Select
             AutoSizeAxes = Axes.Both;
             Children = new Drawable[]
             {
-                new Container
+                textContainer = new Container
                 {
                     Size = new Vector2(100, 50),
                     Child = spriteText = new OsuSpriteText

osu.Game/Screens/Select/FooterButtonRandom.cs

@@ -0,0 +1,56 @@
+// 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.Framework.Graphics.Sprites;
+using osu.Framework.Input.Events;
+using osu.Game.Graphics.Sprites;
+using System;
+
+namespace osu.Game.Screens.Select
+{
+    public class FooterButtonRandom : FooterButton
+    {
+        private readonly SpriteText secondaryText;
+        private bool secondaryActive;
+
+        public FooterButtonRandom()
+        {
+            textContainer.Add(secondaryText = new OsuSpriteText
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                Text = @"rewind",
+                Alpha = 0
+            });
+        }
+
+        protected override bool OnKeyDown(KeyDownEvent e)
+        {
+            secondaryActive = e.ShiftPressed;
+            updateText();
+            return base.OnKeyDown(e);
+        }
+
+        protected override bool OnKeyUp(KeyUpEvent e)
+        {
+            secondaryActive = e.ShiftPressed;
+            updateText();
+            return base.OnKeyUp(e);
+        }
+
+        private void updateText()
+        {
+            if (secondaryActive)
+            {
+                spriteText.FadeOut(120, Easing.InQuad);
+                secondaryText.FadeIn(120, Easing.InQuad);
+            }
+            else
+            {
+                spriteText.FadeIn(120, Easing.InQuad);
+                secondaryText.FadeOut(120, Easing.InQuad);
+            }
+        }
+    }
+}

osu.Game/Screens/Select/SongSelect.cs

@@ -225,7 +225,7 @@ namespace osu.Game.Screens.Select
             if (Footer != null)
             {
                 Footer.AddButton(new FooterButtonMods(selectedMods), @"mods", colours.Yellow, ModSelect, Key.F1);
-                Footer.AddButton(new FooterButton(), @"random", colours.Green, triggerRandom, Key.F2);
+                Footer.AddButton(new FooterButtonRandom(), @"random", colours.Green, triggerRandom, Key.F2);
                 Footer.AddButton(new FooterButton(), @"options", colours.Blue, BeatmapOptions, Key.F3);
 
                 BeatmapOptions.AddButton(@"Delete", @"all difficulties", FontAwesome.Solid.Trash, colours.Pink, () => delete(Beatmap.Value.BeatmapSetInfo), Key.Number4, float.MaxValue);