protected override void  OnPaint(PaintEventArgs e)
或是this.Paint += new System.Windows.Form.PaintEventHandler(Form_Paint)。

private void Form_Paint(object sender, PaintEventArgs e)
	{
		Graphics g = e.Graphics;
			Rectangle mainRect = new Rectangle(0, 0, 695, 278);
			Region mainRegion = new Region(mainRect);
			e.Graphics.SetClip(mainRegion, CombineMode.Replace);
    			Point point1 = new Point(0, 32);
			Point point2 = new Point(9, 20);
			Point point3 = new Point(21, 13);
			Point point4 = new Point(34, 9);
    			// 创建一个以点为元素的数组
			Point[] curvePoints = { point1, point2, point3, point4 };
			// 创建一个GraphicsPath对象并添加一条曲线
			GraphicsPath myPath = new GraphicsPath();
			myPath.AddCurve(curvePoints, 0, 3, 0.8f);
			myPath.AddLine(36, 9, 378, 9);
			point1.X=378;point1.Y=9;
			point2.X=387;point2.Y=5;
			point3.X=394;point3.Y=0;
			Point[] curvePoints2 = { point1, point2, point3 };
			myPath.AddCurve(curvePoints2, 0, 2, 0.8f);
			myPath.AddLine(394, 0, 0, 0);
			Region ExcludeRegion3 = new Region(myPath);
			e.Graphics.ExcludeClip(ExcludeRegion3);
    
			GraphicsPath myPath3 = new GraphicsPath();
			point1.X=0;point1.Y=180;
			point2.X=19;point2.Y=198;
			point3.X=62;point3.Y=204;
			point4.X=83;point4.Y=221;
			Point point5 = new Point(93, 248);
			Point point6 = new Point(102, 267);
			Point point7 = new Point(125, 278);
			Point[] curvePoints3 = { point1, point2, point3, point4, 
point5, point6, point7 };
			myPath3.AddCurve(curvePoints3, 0, 6, 0.8f);
			myPath3.AddLine(125, 278, 90, 300);
			myPath3.AddLine(90, 300, 0, 300);
			Region ExcludeRegion2 = new Region(myPath3);
			e.Graphics.ExcludeClip(ExcludeRegion2);
			point1.X=454;point1.Y=0;
			point2.X=470;point2.Y=12;
			point3.X=481;point3.Y=34;
			Point[] curvePoints4 = { point1, point2, point3 };
			GraphicsPath myPath2 = new GraphicsPath();
			myPath2.AddCurve(curvePoints4, 0, 2, 0.8f);
			myPath2.AddLine(481, 30, 481, 76);
			myPath2.AddLine(481, 76, 495, 76);
			myPath2.AddLine(495, 76, 495, 0);
			Region ExcludeRegion4 = new Region(myPath2);
			e.Graphics.ExcludeClip(ExcludeRegion4);
			GraphicsPath myPath5 = new GraphicsPath();
			point1.X=481;point1.Y=76;
			point2.X=494;point2.Y=115;
			point3.X=481;point3.Y=158;
			Point[] curvePoints5 = { point1, point2, point3 };
			myPath5.AddCurve(curvePoints5, 0, 2, 0.8f);
			myPath5.AddLine(481, 158, 481, 279);
			myPath5.AddLine(481, 255, 495, 279);
			myPath5.AddLine(495, 279, 495, 0);
			Region ExcludeRegion6 = new Region(myPath5);
			e.Graphics.ExcludeClip(ExcludeRegion6);

			point1.X=480;point1.Y=250;
			point2.X=469;point2.Y=264;
			point3.X=446;point3.Y=278;
			Point[] curvePoints6 = { point1, point2, point3 };
			GraphicsPath myPath4 = new GraphicsPath();
			myPath4.AddCurve(curvePoints6, 0, 2, 0.8f);
			myPath4.AddLine(450, 277, 495, 279);
			Region ExcludeRegion5 = new Region(myPath4);
			e.Graphics.ExcludeClip(ExcludeRegion5);

			e.Graphics.DrawImage(img, 0, 0, 695,278);
    
			// 重设剪切好的区域
			e.Graphics.ResetClip();
	}