osu/osu.Game/Graphics/UserInterface/ProgressBar.cs

// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE

using System;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Shapes;
using osu.Framework.Graphics.UserInterface;
using OpenTK.Graphics;

namespace osu.Game.Graphics.UserInterface
{
    public class ProgressBar : SliderBar<double>
    {
        public Action<double> OnSeek;

        private readonly Box fill;
        private readonly Box background;

        public Color4 FillColour
        {
            set { fill.FadeColour(value, 150, Easing.OutQuint); }
        }

        public Color4 BackgroundColour
        {
            set
            {
                background.Alpha = 1;
                background.Colour = value;
            }
        }

        public double EndTime
        {
            set { CurrentNumber.MaxValue = value; }
        }

        public double CurrentTime
        {
            set { CurrentNumber.Value = value; }
        }

        public ProgressBar()
        {
            CurrentNumber.MinValue = 0;
            CurrentNumber.MaxValue = 1;
            RelativeSizeAxes = Axes.X;

            Children = new Drawable[]
            {
                background = new Box
                {
                    Alpha = 0,
                    RelativeSizeAxes = Axes.Both
                },
                fill = new Box { RelativeSizeAxes = Axes.Y }
            };
        }

        protected override void UpdateValue(float value)
        {
            fill.Width = value * UsableWidth;
        }

        protected override void OnUserChange() => OnSeek?.Invoke(Current);
    }
}