我无法对标准按钮进行正常的四舍五入

Question

我正在尝试进行正常的四舍五入。而且我无法平滑按钮的四舍五入。 第二个问题，我该如何对按钮进行四舍五入，以使BackgroundImage中使用的照片不会四舍五入？？

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

namespace Test_Project.SupportClass
{
    public class Buttom_Class4 : Button
    {
        public Buttom_Class4()
        {
            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
            SetStyle(ControlStyles.SupportsTransparentBackColor, true);
            SetStyle(ControlStyles.Opaque, true);
            SetStyle(ControlStyles.ResizeRedraw, true);
        }


        private int radius = 20;
        [DefaultValue(20)]
        public int Radius
        {
            get { return radius; }
            set
            {
                radius = value;
                this.RecreateRegion();
            }
        }
        private GraphicsPath GetRoundRectagle(Rectangle bounds, int radius)
        {
            GraphicsPath path = new GraphicsPath();
            path.AddArc(bounds.X, bounds.Y, radius, radius, 180, 90);
            path.AddArc(bounds.X + bounds.Width - radius, bounds.Y, radius, radius, 270, 90);
            path.AddArc(bounds.X + bounds.Width - radius, bounds.Y + bounds.Height - radius,
                        radius, radius, 0, 90);
            path.AddArc(bounds.X, bounds.Y + bounds.Height - radius, radius, radius, 90, 90);
            path.CloseAllFigures();
            return path;
        }
        private void RecreateRegion()
        {
            var bounds = ClientRectangle;
            bounds.Width--; bounds.Height--;
            using (var path = GetRoundRectagle(bounds, this.Radius))
                this.Region = new Region(path);
            this.Invalidate();
        }

        protected override void OnSizeChanged(EventArgs e)
        {
            base.OnSizeChanged(e);
            this.RecreateRegion();
        }
    }
}