better resizing

osu.Game/Screens/Play/Options/OptionContainer.cs

@@ -3,6 +3,7 @@
 
 using OpenTK;
 using OpenTK.Graphics;
+using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Sprites;
@@ -19,7 +20,8 @@ namespace osu.Game.Screens.Play.Options
         /// </summary>
         public abstract string Title { get; }
 
-        private readonly FillFlowContainer content;
+        private readonly OptionDropdown content;
+        private readonly SimpleButton button;
         private bool contentIsVisible;
 
         protected OptionContainer()
@@ -65,7 +67,7 @@ namespace osu.Game.Screens.Play.Options
                                     Font = @"Exo2.0-Bold",
                                     Margin = new MarginPadding { Left = 10 },
                                 },
-                                new SimpleButton
+                                button = new SimpleButton
                                 {
                                     Origin = Anchor.Centre,
                                     Anchor = Anchor.CentreRight,
@@ -76,21 +78,21 @@ namespace osu.Game.Screens.Play.Options
                                 },
                             }
                         },
-                        content = new FillFlowContainer
+                        content = new OptionDropdown
                         {
-                            Direction = FillDirection.Vertical,
                             RelativeSizeAxes = Axes.X,
-                            AutoSizeAxes = Axes.Y,
-                            Origin = Anchor.TopCentre,
-                            Anchor = Anchor.TopCentre,
-                            Padding = new MarginPadding(15),
-                            Spacing = new Vector2(0, 10),
                         }
                     }
                 },
             };
         }
 
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            content.StateChanged += (c, s) => button.FadeColour(s == Visibility.Visible ? colours.Yellow : Color4.White, 200, EasingTypes.OutQuint);
+        }
+
         public new void Add(Drawable drawable)
         {
             content.Add(drawable);
@@ -98,12 +100,12 @@ namespace osu.Game.Screens.Play.Options
 
         private void triggerContentVisibility()
         {
+            contentIsVisible = !contentIsVisible;
+
             if (contentIsVisible)
                 content.Show();
             else
                 content.Hide();
-
-            contentIsVisible = !contentIsVisible;
         }
     }
 }

osu.Game/Screens/Play/Options/OptionDropdown.cs

@@ -0,0 +1,50 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using OpenTK;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+
+namespace osu.Game.Screens.Play.Options
+{
+    public class OptionDropdown : OverlayContainer
+    {
+        private const float transition_duration = 600;
+
+        private FillFlowContainer content;
+
+        public OptionDropdown()
+        {
+            Children = new Drawable[]
+            {
+                content = new FillFlowContainer
+                {
+                    Direction = FillDirection.Vertical,
+                    RelativeSizeAxes = Axes.X,
+                    AutoSizeAxes = Axes.Y,
+                    Origin = Anchor.TopCentre,
+                    Anchor = Anchor.TopCentre,
+                    Padding = new MarginPadding(15),
+                    Spacing = new Vector2(0, 10),
+                }
+            };
+        }
+
+        public new void Add(Drawable drawable)
+        {
+            content.Add(drawable);
+        }
+
+        protected override void PopIn()
+        {
+            ResizeTo(new Vector2(1, content.Height), transition_duration, EasingTypes.OutQuint);
+            FadeIn(transition_duration, EasingTypes.OutQuint);
+        }
+
+        protected override void PopOut()
+        {
+            ResizeTo(new Vector2(1, 0), transition_duration, EasingTypes.OutQuint);
+            FadeOut(transition_duration);
+        }
+    }
+}

osu.Game/osu.Game.csproj

@@ -236,6 +236,7 @@
     <Compile Include="Screens\Play\Options\CollectionOptions.cs" />
     <Compile Include="Screens\Play\Options\DiscussionOptions.cs" />
     <Compile Include="Screens\Play\Options\OptionContainer.cs" />
+    <Compile Include="Screens\Play\Options\OptionDropdown.cs" />
     <Compile Include="Screens\Play\Options\OptionsDisplay.cs" />
     <Compile Include="Screens\Play\Options\PlaybackOptions.cs" />
     <Compile Include="Screens\Play\PauseContainer.cs" />