osu/osu.Game/Overlays/Options/SidebarButton.cs

using System;
using OpenTK;
using OpenTK.Graphics;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Containers;
using osu.Framework.Graphics.Sprites;
using osu.Framework.Input;
using osu.Game.Graphics;

namespace osu.Game.Overlays.Options
{
    public class SidebarButton : Container
    {
        private TextAwesome drawableIcon;
        private SpriteText headerText;
        private Box backgroundBox;
        private Box selectionIndicator;
        public Action Action;

        private OptionsSection section;
        public OptionsSection Section
        {
            get
            {
                return section;
            }
            set
            {
                section = value;
                headerText.Text = value.Header;
                drawableIcon.Icon = value.Icon;
            }
        }

        private bool selected;
        public bool Selected
        {
            get { return selected; }
            set
            {
                selected = value;
                if (selected)
                    selectionIndicator.FadeIn(50);
                else
                    selectionIndicator.FadeOut(50);
            }
        }

        public SidebarButton()
        {
            Height = OptionsSidebar.default_width;
            RelativeSizeAxes = Axes.X;
            Children = new Drawable[]
            {
                    backgroundBox = new Box
                    {
                        RelativeSizeAxes = Axes.Both,
                        BlendingMode = BlendingMode.Additive,
                        Colour = new Color4(60, 60, 60, 255),
                        Alpha = 0,
                    },
                    new Container
                    {
                        Width = OptionsSidebar.default_width,
                        RelativeSizeAxes = Axes.Y,
                        Children = new[]
                        {
                            drawableIcon = new TextAwesome
                            {
                                Anchor = Anchor.Centre,
                                Origin = Anchor.Centre,
                            },
                        }
                    },
                    headerText = new SpriteText
                    {
                        Position = new Vector2(OptionsSidebar.default_width + 10, 0),
                        Anchor = Anchor.CentreLeft,
                        Origin = Anchor.CentreLeft,
                    },
                    selectionIndicator = new Box
                    {
                        Alpha = 0,
                        RelativeSizeAxes = Axes.Y,
                        Width = 5,
                        Anchor = Anchor.CentreRight,
                        Origin = Anchor.CentreRight,
                        Colour = new Color4(233, 103, 161, 255)
                    }
            };
        }

        protected override bool OnClick(InputState state)
        {
            Action?.Invoke();
            backgroundBox.FlashColour(Color4.White, 400);
            return true;
        }

        protected override bool OnHover(InputState state)
        {
            backgroundBox.FadeTo(0.4f, 200);
            return base.OnHover(state);
        }

        protected override void OnHoverLost(InputState state)
        {
            backgroundBox.FadeTo(0, 200);
            base.OnHoverLost(state);
        }
    }
}