osu-lazer/osu.Game.Rulesets.Mania/Skinning/Argon/ArgonManiaComboCounter.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.Graphics;
using osu.Game.Rulesets.UI.Scrolling;
using osu.Game.Screens.Play.HUD;

namespace osu.Game.Rulesets.Mania.Skinning.Argon
{
    public partial class ArgonManiaComboCounter : ArgonComboCounter
    {
        protected override bool DisplayXSymbol => false;

        [Resolved]
        private IScrollingInfo scrollingInfo { get; set; } = null!;

        private IBindable<ScrollingDirection> direction = null!;

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

            // the logic of flipping the position of the combo counter w.r.t. the direction does not work with "Closest" anchor,
            // because it always forces the anchor to be top or bottom based on scrolling direction.
            UsesFixedAnchor = true;

            direction = scrollingInfo.Direction.GetBoundCopy();
            direction.BindValueChanged(_ => updateAnchor());

            // two schedules are required so that updateAnchor is executed in the next frame,
            // which is when the combo counter receives its Y position by the default layout in ArgonManiaSkinTransformer.
            Schedule(() => Schedule(updateAnchor));
        }

        private void updateAnchor()
        {
            // if the anchor isn't a vertical center, set top or bottom anchor based on scroll direction
            if (!Anchor.HasFlag(Anchor.y1))
            {
                Anchor &= ~(Anchor.y0 | Anchor.y2);
                Anchor |= direction.Value == ScrollingDirection.Up ? Anchor.y2 : Anchor.y0;
            }

            // change the sign of the Y coordinate in line with the scrolling direction.
            // i.e. if the user changes direction from down to up, the anchor is changed from top to bottom, and the Y is flipped from positive to negative here.
            Y = Math.Abs(Y) * (direction.Value == ScrollingDirection.Up ? -1 : 1);
        }
    }
}