c# 畫三角形，並填充顏色

目前知道有兩種方法：畫多邊形、GraphicsPath。但是用畫多邊形的方式畫三角形不太好。老畫不正的，放大就明顯了。

代碼1     Point point1 = new Point(0, 0);
2     Point point2 = new Point(11, 0);
3     Point point3 = new Point(5, 8);
4     Point[] pntArr = {point1, point2, point3};
5 
6     e.Graphics.FillPolygon(Brushes.Red, pntArr);
7 

代碼 1                 int len = 10;                       
 2                 int x = 0;
 3                 int y = 0;
 4                 Point[] pntArr = new Point[3];
 5                 pntArr[0] = new Point(x, y);
 6                 pntArr[1] = new Point(x - len, y);
 7                 pntArr[2] = new Point(x - len / 2, (int)(len * Math.Sqrt(3) / 2 + y));
 8                 GraphicsPath path = new GraphicsPath();
 9                 path.AddLines(pntArr);
10                 e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
11                 e.Graphics.FillPath(Brushes.Red, path);               
12                 e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.Default;
13