optimizer/Optimizer/Controls/MoonProgress.cs

using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace Optimizer {
    internal sealed class MoonProgress : ProgressBar {
        public MoonProgress() {
            DoubleBuffered = true;
            this.SetStyle(ControlStyles.UserPaint, true);
        }

        protected override void OnPaint(PaintEventArgs e) {
            LinearGradientBrush brush = null;
            Rectangle rec = new Rectangle(0, 0, this.Width, this.Height);

            if (ProgressBarRenderer.IsSupported)
                ProgressBarRenderer.DrawHorizontalBar(e.Graphics, rec);

            rec.Width = (int)(rec.Width * ((double)base.Value / Maximum)) - 4;
            rec.Height -= 4;
            brush = new LinearGradientBrush(rec, OptionsHelper.ForegroundAccentColor, OptionsHelper.ForegroundColor, LinearGradientMode.Vertical);
            e.Graphics.FillRectangle(brush, 2, 2, rec.Width, rec.Height);
        }
    }
}