public void DrawSinCurbe()
  {
       Point firstPoint = new Point(50, 50);//描き始め
       Point secondPoint = new Point(350, firstPoint.Y);//描き終わり
       bool smoothSet = false;//false:通常描画　true:円滑描画
       Font font = new Font("Times New Roman", 10f);//フォント設定
       Bitmap imgBitmap = new Bitmap(600, 600); //PictureBoxのサイズ
       pictureBox.Image = imgBitmap;
       Pen drawPen = new Pen(Color.Black, 0.1f);//描く線のPen設定
       Brush brush = new SolidBrush(Color.Black);//文字色
       Graphics grf = Graphics.FromImage(pictureBox.Image);

       Bitmap sinBmp = SetSinCurve(drawPen,firstPoint,secondPoint,smoothSet);

       grf.DrawString("通常描画", font, brush, 60f, 20f);
       grf.DrawImage(sinBmp, 10, 10);
       //円滑描画設定
       firstPoint = new Point(50 * 100, 50 * 100);//各値を100倍
       secondPoint = new Point(350 * 100, firstPoint.Y);//各値を100倍
       smoothSet = true;

      sinBmp = SetSinCurve(drawPen,firstPoint, secondPoint,smoothSet);

       grf.DrawString("円滑描画", font, brush, 60ｆ, 90f);
       grf.DrawImage (sinBmp, 10, 80);
       grf.Dispose();
  }
　　　//linePen:描く線の色
　　　//startPoint:曲線の描き始め
　　　//endPoint:曲線の描き終わり
　　　//smooth://false:通常描画　true:円滑描画
   public Bitmap SetSinCurve(Pen linePen, Point startPoint, Point endPoint,bool smooth)
  {
       double width = endPoint.X - startPoint.X;
       double amplitude = width / 20; // 振幅
       double resolution = 200; // 点の数
       Point[] curvePoints = new Point[(int)resolution + 1];//サインカーブPoint配列
       Bitmap bitmap = new Bitmap((int)(width * 2), (int)(amplitude * 5));
       Graphics g = Graphics.FromImage(bitmap);
       g.PageUnit = GraphicsUnit.Pixel;
       if (smooth) { g.PageScale = 0.01f; }//円滑描画時1/100スケール
       g.SmoothingMode = SmoothingMode.HighQuality;
       //サインカーブ計算
       for (int i = 0; i <= resolution; i++)
      {
           double t = (double)i / resolution;
           double x = startPoint.X + t * width;
           double y = startPoint.Y + Math.Sin(-t * 2 * Math.PI) * amplitude;
           curvePoints[i] = new Point((int)x, (int)y);//配列に代入
      }
       g.DrawLines(linePen, curvePoints);
       g.Dispose();
       return bitmap;
  }