osu/osu.Game/Graphics/UserInterface/Nub.cs

// 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 System;
using osu.Framework.Allocation;
using osu.Framework.Bindables;
using osu.Framework.Extensions.Color4Extensions;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Containers;
using osu.Framework.Graphics.Effects;
using osu.Framework.Graphics.Shapes;
using osu.Framework.Graphics.UserInterface;
using osu.Game.Overlays;
using osuTK.Graphics;

namespace osu.Game.Graphics.UserInterface
{
    public abstract partial class Nub : Container, IHasCurrentValue<bool>, IHasAccentColour
    {
        protected const float BORDER_WIDTH = 3;

        private readonly Box fill;
        private readonly Container main;

        /// <summary>
        ///  Implements the shape for the nub, allowing for any type of container to be used.
        /// </summary>
        /// <returns></returns>
        protected abstract Container CreateNubContainer();

        protected Nub()
        {
            InternalChild = main = CreateNubContainer();

            main.Add(fill = new Box
            {
                RelativeSizeAxes = Axes.Both,
                Alpha = 0,
                AlwaysPresent = true,
            });
        }

        [BackgroundDependencyLoader(true)]
        private void load(OverlayColourProvider? colourProvider, OsuColour colours)
        {
            AccentColour = colourProvider?.Highlight1 ?? colours.Pink;
            GlowingAccentColour = colourProvider?.Highlight1.Lighten(0.2f) ?? colours.PinkLighter;
            GlowColour = colourProvider?.Highlight1 ?? colours.PinkLighter;

            main.EdgeEffect = new EdgeEffectParameters
            {
                Colour = GlowColour.Opacity(0),
                Type = EdgeEffectType.Glow,
                Radius = 8,
                Roundness = 4,
            };
        }

        protected override void LoadComplete()
        {
            base.LoadComplete();

            Current.BindValueChanged(onCurrentValueChanged, true);
        }

        private bool glowing;

        public bool Glowing
        {
            get => glowing;
            set
            {
                glowing = value;

                if (value)
                {
                    main.FadeColour(GlowingAccentColour.Lighten(0.5f), 40, Easing.OutQuint)
                        .Then()
                        .FadeColour(GlowingAccentColour, 800, Easing.OutQuint);

                    main.FadeEdgeEffectTo(Color4.White.Opacity(0.1f), 40, Easing.OutQuint)
                        .Then()
                        .FadeEdgeEffectTo(GlowColour.Opacity(0.1f), 800, Easing.OutQuint);
                }
                else
                {
                    main.FadeEdgeEffectTo(GlowColour.Opacity(0), 800, Easing.OutQuint);
                    main.FadeColour(AccentColour, 800, Easing.OutQuint);
                }
            }
        }

        private readonly Bindable<bool> current = new Bindable<bool>();

        public Bindable<bool> Current
        {
            get => current;
            set
            {
                ArgumentNullException.ThrowIfNull(value);

                current.UnbindBindings();
                current.BindTo(value);
            }
        }

        private Color4 accentColour;

        public Color4 AccentColour
        {
            get => accentColour;
            set
            {
                accentColour = value;
                if (!Glowing)
                    main.Colour = value;
            }
        }

        private Color4 glowingAccentColour;

        public Color4 GlowingAccentColour
        {
            get => glowingAccentColour;
            set
            {
                glowingAccentColour = value;
                if (Glowing)
                    main.Colour = value;
            }
        }

        private Color4 glowColour;

        public Color4 GlowColour
        {
            get => glowColour;
            set
            {
                glowColour = value;

                var effect = main.EdgeEffect;
                effect.Colour = Glowing ? value : value.Opacity(0);
                main.EdgeEffect = effect;
            }
        }

        private void onCurrentValueChanged(ValueChangedEvent<bool> filled)
        {
            const double duration = 200;

            fill.FadeTo(filled.NewValue ? 1 : 0, duration, Easing.OutQuint);

            if (filled.NewValue)
            {
                main.ResizeWidthTo(1, duration, Easing.OutElasticHalf);
                main.TransformTo(nameof(BorderThickness), 8.5f, duration, Easing.OutElasticHalf);
            }
            else
            {
                main.ResizeWidthTo(0.75f, duration, Easing.OutQuint);
                main.TransformTo(nameof(BorderThickness), BORDER_WIDTH, duration, Easing.OutQuint);
            }
        }
    }
}