osu-lazer/osu.Game/Overlays/OverlayColourProvider.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 osuTK;
using osuTK.Graphics;

namespace osu.Game.Overlays
{
    public class OverlayColourProvider
    {
        public OverlayColourScheme ColourScheme { get; private set; }

        public OverlayColourProvider(OverlayColourScheme colourScheme)
        {
            ColourScheme = colourScheme;
        }

        // Note that the following five colours are also defined in `OsuColour` as `{colourScheme}{0,1,2,3,4}`.
        // The difference as to which should be used where comes down to context.
        // If the colour in question is supposed to always match the view in which it is displayed theme-wise, use `OverlayColourProvider`.
        // If the colour usage is special and in general differs from the surrounding view in choice of hue, use the `OsuColour` constants.
        public Color4 Colour0 => getColour(1, 0.8f);
        public Color4 Colour1 => getColour(1, 0.7f);
        public Color4 Colour2 => getColour(0.8f, 0.6f);
        public Color4 Colour3 => getColour(0.6f, 0.5f);
        public Color4 Colour4 => getColour(0.4f, 0.3f);

        public Color4 Highlight1 => getColour(1, 0.7f);
        public Color4 Content1 => getColour(0.4f, 1);
        public Color4 Content2 => getColour(0.4f, 0.9f);
        public Color4 Light1 => getColour(0.4f, 0.8f);
        public Color4 Light2 => getColour(0.4f, 0.75f);
        public Color4 Light3 => getColour(0.4f, 0.7f);
        public Color4 Light4 => getColour(0.4f, 0.5f);
        public Color4 Dark1 => getColour(0.2f, 0.35f);
        public Color4 Dark2 => getColour(0.2f, 0.3f);
        public Color4 Dark3 => getColour(0.2f, 0.25f);
        public Color4 Dark4 => getColour(0.2f, 0.2f);
        public Color4 Dark5 => getColour(0.2f, 0.15f);
        public Color4 Dark6 => getColour(0.2f, 0.1f);
        public Color4 Foreground1 => getColour(0.1f, 0.6f);
        public Color4 Background1 => getColour(0.1f, 0.4f);
        public Color4 Background2 => getColour(0.1f, 0.3f);
        public Color4 Background3 => getColour(0.1f, 0.25f);
        public Color4 Background4 => getColour(0.1f, 0.2f);
        public Color4 Background5 => getColour(0.1f, 0.15f);
        public Color4 Background6 => getColour(0.1f, 0.1f);

        /// <summary>
        /// Changes the value of <see cref="ColourScheme"/> to a different colour scheme.
        /// Note that this does not trigger any kind of signal to any drawable that received colours from here, all drawables need to be updated manually.
        /// </summary>
        /// <param name="colourScheme">The proposed colour scheme.</param>
        public void ChangeColourScheme(OverlayColourScheme colourScheme)
        {
            ColourScheme = colourScheme;
        }

        private Color4 getColour(float saturation, float lightness) => Color4.FromHsl(new Vector4(getBaseHue(ColourScheme), saturation, lightness, 1));

        private static float getBaseHue(OverlayColourScheme colourScheme)
        {
            // intentionally round hue number back to zero when it's 360, because that number apparently gives off a nice-looking gray colour scheme but is totally against expectation (maybe we can use this one day).
            int hueNumber = (int)colourScheme % 360;
            return hueNumber / 360f;
        }
    }

    // See https://github.com/ppy/osu-web/blob/5a536d217a21582aad999db50a981003d3ad5659/app/helpers.php#L1620-L1628
    public enum OverlayColourScheme
    {
        Red = 0,
        Orange = 45,
        Lime = 90,
        Green = 125,
        Aquamarine = 160,
        Blue = 200,
        Purple = 255,
        Plum = 320,
        Pink = 333,
    }
}