你可以根據實際要求，修改下：

//例項化 Bitmap

Bitmap image = new Bitmap(300, 300);//圖片尺寸

//從 Bitmap 例項建立Graphics例項

Graphics graphics = Graphics.FromImage(image);

//座標原點轉換到圖片左下角(GDI+預設原點在左上角)

graphics.TranslateTransform(0, 298);

//以白色填充圖片

graphics.Clear(Color.White);

//畫座標軸

Pen pen=new Pen(Color.Black);

graphics.DrawLine(pen, new Point(0, 0), new Point(300, 0));

graphics.DrawLine(pen, new Point(0, 0), new Point(0, -300));

//畫箭頭

graphics.DrawLine(pen, new Point(300, 0), new Point(295, -5));

graphics.DrawLine(pen, new Point(0, -300), new Point(5, -295));

//刻度

for (int i = 20; i < 300; i = i + 20)

{

//x軸

graphics.DrawLine(pen, new Point(i, 0), new Point(i, -5));

//y軸

graphics.DrawLine(pen, new Point(0, i*-1), new Point(5, i*-1));

}

//畫矩形

//假設矩形一個角的座標為80,100

graphics.FillRectangle(Brushes.Blue,0,-100,80,100);

//釋放Graphics物件

graphics.Dispose();

//圖形輸出到網頁

Response.Clear();

//設定Response的MIME

Response.ContentType = "image/pjpeg";

//將圖片儲存到Response的輸出流中

image.Save(Response.OutputStream, ImageFormat.Jpeg);

//寫入到Response輸出流中

image.Dispose();

Response.End();