复制代码 代码如下:

using System;

using System.Collections.Generic;

using System.Text;

using System.Drawing;

using System.IO;

using System.Drawing.Imaging;

namespace Chen

{

public class warterfont

{

public void addtexttoimg(string filename, string text)

{

if (!File.Exists(System.Web.HttpContext.Current.Server.MapPath(filename)))

{

throw new FileNotFoundException("the file don't exist!");

}

if (text == string.Empty)

{

return;

}

//还需要判断文件类型是否为图像类型，这里就不赘述了

Image image = Image.FromFile(System.Web.HttpContext.Current.Server.MapPath(filename));

Bitmap bitmap = new Bitmap(image, image.Width, image.Height);

Graphics g = Graphics.FromImage(bitmap);

float fontsize = 12.0f; //字体大小

float textwidth = text.Length * fontsize; //文本的长度

//下面定义一个矩形区域，以后在这个矩形里画上白底黑字

float rectx = 0;

float recty = 0;

float rectwidth = text.Length * (fontsize + 8);

float rectheight = fontsize + 8; //声明矩形域

RectangleF textarea = new RectangleF(rectx, recty, rectwidth, rectheight);

Font font = new Font("宋体", fontsize); //定义字体

Brush whitebrush = new SolidBrush(Color.White); //白笔刷，画文字用

Brush blackbrush = new SolidBrush(Color.Black); //黑笔刷，画背景用

g.FillRectangle(blackbrush, rectx, recty, rectwidth, rectheight);

g.DrawString(text, font, whitebrush, textarea);

MemoryStream ms = new MemoryStream(); //保存为jpg类型

bitmap.Save(ms, ImageFormat.Jpeg); //输出处理后的图像，这里为了演示方便，我将图片显示在页面中了

bitmap.Save(System.Web.HttpContext.Current.Server.MapPath("/" + "aa.jpg"), ImageFormat.Jpeg); //保存到磁盘上

System.Web.HttpContext.Current.Response.Clear();

System.Web.HttpContext.Current.Response.ContentType = "image/jpeg";

System.Web.HttpContext.Current.Response.BinaryWrite(ms.ToArray());

g.Dispose();

bitmap.Dispose();

image.Dispose();

}

}

}