txt文本文件生成图片文件

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;


public partial class wxDown : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
    {
        ConvertTextFileToImage(Server.MapPath("~/aa.txt"), Server.MapPath("~/aa.png"));  
    }

void ConvertTextFileToImage(String textFile, String imageFile)
    {
        System.Drawing.Font drawFont = new System.Drawing.Font("宋体", 12);
        System.Drawing.Bitmap image = new System.Drawing.Bitmap(1, 1);
        System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
        String text = System.IO.File.ReadAllText(textFile, System.Text.Encoding.GetEncoding("GB2312"));
        System.Drawing.SizeF sf = g.MeasureString(text, drawFont, 1024); //设置一个显示的宽度   
        image = new System.Drawing.Bitmap(image, new System.Drawing.Size(Convert.ToInt32(sf.Width), Convert.ToInt32(sf.Height)));
        g = System.Drawing.Graphics.FromImage(image);
        g.Clear(System.Drawing.Color.White);
        g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAliasGridFit;
        g.DrawString(text, drawFont, System.Drawing.Brushes.Black, new System.Drawing.RectangleF(new System.Drawing.PointF(0, 0), sf));
        image.Save(imageFile, System.Drawing.Imaging.ImageFormat.Png);
        g.Dispose();
        image.Dispose();
    }  
}