转：上传图片并给图片加水印（公共类积累）

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
/// <summary>
/// 上传图片加水印
/// 作者：
/// 时间：2006-12-8
/// E-mail：jiay_yong@163.com
/// 说明：文字水印的位置有待完善，建议用图片水印
/// </summary>

public partial class UpFile : System.Web.UI.UserControl
{

    string _strNewFileFolder = "UpLoad/";           //文件上传的目录
    int _NewImgpx = 300;                            //缩略图尺寸
    bool _IsThumb = true;                           //是否启用缩略图 true：启用  false：不启用
    bool _IsWatermark = true;                       //是否启用水印 true：启用  false：不启用
    int _WatemarkPos = 9;                           //水印位置 1：左上角 2：水平居中垂直顶部 3：右上角 4：垂直居中水平靠左 5：居中 6：垂直居中水平靠右 7：左下角 8：水平居中垂直底部 9：右下角
    string _WatemarkType = "img";                   //水印类型 txt：文字水印 img：图片水印
    string _WatemarkText = "PayOpen薪酬公开分析网"; //水印文字
    string _WatemarkFont = "Verdana";               //水印字体
    int _WatemarkFontSize = 12;                     //水印字号
    string _WatemarkImg = "mark.png";               //水印图片
    int _FileSizeMax = 2048;                        //限制上传文件大小

    string _srcFileName;                            //上传文件原文件名
    string _srcFileExtension;                       //扩展名
    string _strFileName;                            //新文件名
    string _strFileType;                            //文件类型
    int _strFileSize;                               //文件大小 单位 KB
    int _OldFileWidth;                              //原图宽度
    int _OldFileHeight;                             //原图高度
    int _NewImgHeight;                              //缩略图高度
    int _NewImgWidth;                               //缩略图宽度
    string _thumbImgPath;                           //缩略图完整地址
    string _imagePath;                              //返回上传图片完整地址
    string _errMsg;                                 //返回出错提示

    string _strFileFolder;
    int _WatemarkPosX = 5;
    int _WatemarkPosY = 5;

    DateTime now = DateTime.Now;                    //取当前的时间到DateTime类的对象now中

    public delegate void OnUploadEvent(object sender, EventArgs e);
    public event OnUploadEvent OnUpload;

    /// <summary>
    /// 设置文件上传的目录
    /// </summary>
    public string strNewFileFolder
    {
        set { _strNewFileFolder = value; }
    }

    /// <summary>
    /// 设置缩略图的尺寸
    /// </summary>
    public int NewImgpx
    {
        set { _NewImgpx = value; }
    }

    /// <summary>
    /// 是否启用缩略图
    /// </summary>
    /// 
    public bool IsThumb
    {
        set { _IsThumb = value; }
    }

    /// <summary>
    /// 是否启用水印
    /// </summary>
    public bool IsWatermark
    {
        set { _IsWatermark = value; }
    }
    
    /// <summary>
    /// 设置水印位置
    /// </summary>
    public int WatemarkPos
    {
        set { _WatemarkPos = value; }
    }
    
    /// <summary>
    /// 设置水印类型 txt：文字水印 img：图片水印
    /// </summary>
    public string WatemarkType
    {
        set { _WatemarkType = value; }
    }

    /// <summary>
    /// 设置水印文字
    /// </summary>
    public string WatemarkText
    {
        set { _WatemarkText = value; }
    }

    /// <summary>
    /// 设置水印字体
    /// </summary>
    public string WatemarkFont
    {
        set { _WatemarkFont = value; }
    }

    /// <summary>
    /// 设置水印字号
    /// </summary>
    public int WatemarkFontSize
    {
        set { _WatemarkFontSize = value; }
    }

    /// <summary>
    /// 设置水印图片
    /// </summary>
    public string WatemarkImg
    {
        set { _WatemarkImg = value; }
    }
    /// <summary>
    /// 设置上传文件的限制大小
    /// </summary>
    public int FileSizeMax
    {
        set { _FileSizeMax = value; }
    }

    /// <summary>
    /// 上传文件原文件名
    /// </summary>
    public string srcFileName
    {
        get { return _srcFileName; }
    }

    /// <summary>
    /// 扩展名
    /// </summary>
    public string srcFileExtension
    {
        get { return _srcFileExtension; }
    }

    /// <summary>
    /// 新文件名
    /// </summary>
    public string strFileName
    {
        get { return _strFileName; }
    }

    /// <summary>
    /// 文件类型
    /// </summary>
    public string strFileType
    {
        get { return _strFileType; }
    }
    /// <summary>
    /// 文件大小 单位 KB
    /// </summary>
    public int strFileSize
    {
        get { return _strFileSize; }
    }

    /// <summary>
    /// 原图宽度
    /// </summary>
    public int OldFileWidth
    {
        get { return _OldFileWidth; }
    }

    /// <summary>
    /// 原图高度
    /// </summary>
    public int OldFileHeight
    {
        get { return _OldFileHeight; }
    }

    /// <summary>
    /// 缩略图高度
    /// </summary>
    public int NewImgHeight
    {
        get { return _NewImgHeight; }
    }

    /// <summary>
    /// 缩略图宽度
    /// </summary>
    public int NewImgWidth
    {
        get { return _NewImgWidth; }
    }

    /// <summary>
    /// 缩略图完整地址
    /// </summary>
    public string thumbImgPath
    {
        get { return _thumbImgPath; }
    }

    /// <summary>
    /// 返回上传图片完整地址
    /// </summary>
    public string ImagePath
    {
        get { return _imagePath; }
    }

    /// <summary>
    /// 返回出错提示
    /// </summary>
    public string ErrMsg
    {
        get { return _errMsg; }
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        _WatemarkImg = Server.MapPath("./") + _WatemarkImg; //水印图片

        //文件上传的目录
        _strNewFileFolder += now.Year.ToString() + "/";
        _strFileFolder = Server.MapPath("./") + _strNewFileFolder;
    }

    protected void Button1_ServerClick(object sender, EventArgs e)
    {
        //随机数
        Random Rnd = new Random();
        int strRnd = Rnd.Next(1, 99);

        //新文件名称
        string strFileName = now.Month.ToString() + now.Day.ToString() + now.Hour.ToString() + now.Minute.ToString() + now.Second.ToString() + strRnd.ToString();

        if (UpLoadFile.PostedFile.ContentLength != 0)  //判断选取对话框的文件长度是否为0
        {

            //检测目录是否存在，不存在就建立目录
            if (!Directory.Exists(_strFileFolder))
            {
                Directory.CreateDirectory(_strFileFolder);
            }

            //获取原文件信息
            string srcFile = UpLoadFile.PostedFile.FileName;
            string srcFileName = Path.GetFileName(srcFile.ToString());          //原文件名
            string srcFileExtension = Path.GetExtension(srcFile.ToString());    //原文件扩展名           
            string strFileType = UpLoadFile.PostedFile.ContentType;             //获得文件类型
            int strFileSize = UpLoadFile.PostedFile.ContentLength / _FileSizeMax;       //获得文件体积大小，单位KB


            //限制文件上传大小
            if (strFileSize > _FileSizeMax)
            {
                _errMsg = "上传文件超过限制，文件大小限制为：" + _FileSizeMax + " KB";
                return;
            }

            strFileName = strFileName + srcFileExtension;                       //新文件名包括扩展名
            _imagePath = _strNewFileFolder + strFileName;                       //返回上传后的图片路径

            //输出
            _srcFileName = srcFileName;                 //上传文件原文件名
            _srcFileExtension = srcFileExtension;       //扩展名
            _strFileName = strFileName;                 //新文件名
            _strFileType = strFileType;                 //文件类型
            _strFileSize = strFileSize;                 //文件大小 单位 KB

            //判断是否为图片
            bool IsImg = true;
            if (UpLoadFile.PostedFile.ContentType.IndexOf("image") < 0)
            {
                IsImg = false;
            }

            if (IsImg == false)
            {
                UpLoadFile.PostedFile.SaveAs(_strFileFolder + strFileName);          //非图片文件上传
            }
            else
            {
                //加水印并上传
                if (_IsWatermark == true)
                {

                    System.Drawing.Image image;
                    if (strFileType == "image/bmp") //bmp图片格式
                        image = System.Drawing.Bitmap.FromStream(UpLoadFile.PostedFile.InputStream);
                    else
                        image = System.Drawing.Image.FromStream(UpLoadFile.PostedFile.InputStream);

                    System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);

                    if (_WatemarkType == "txt") //文字水印
                    {

                        //将图片绘制到graphics中
                        g.DrawImage(image, 0, 0, image.Width, image.Height);
                        //设置文字的属性
                        System.Drawing.Font f = new System.Drawing.Font(_WatemarkFont, _WatemarkFontSize);
                        //判断图片的大小，如果图片过小，不写文字
                        if (image.Width < 200)
                            //在此设定在图片上所加的文字
                            _WatemarkText = "";

                        //写的文字的起始位置，x,y坐标
                        _WatemarkPosX = 5;
                        _WatemarkPosY = 5;
                        //设置字体的颜色
                        System.Drawing.Brush b = new System.Drawing.SolidBrush(System.Drawing.Color.White);
                        //写字
                        g.DrawString(_WatemarkText, f, b, _WatemarkPosX, _WatemarkPosY);
                        //释放graphics
                        g.Dispose();

                        //保存加上水印的图片
                        image.Save(_strFileFolder + strFileName);
                        //释放image
                        image.Dispose();

                    }
                    else if (_WatemarkType == "img") //图片水印
                    {

                        System.Drawing.Image copyImage = System.Drawing.Image.FromFile(_WatemarkImg);

                        //水印放置左上角
                        if (_WatemarkPos == 1)
                        {
                            _WatemarkPosX = 5;
                            _WatemarkPosY = 5;
                        }

                        //水平居中垂直顶部
                        if (_WatemarkPos == 2)
                        {
                            _WatemarkPosX = (image.Width - copyImage.Width) / 2;
                            _WatemarkPosY = 5;
                        }

                        //右上角
                        if (_WatemarkPos == 3)
                        {
                            _WatemarkPosX = image.Width - copyImage.Width - 5;
                            _WatemarkPosY = 5;
                        }

                        //垂直居中水平靠左
                        if (_WatemarkPos == 4)
                        {
                            _WatemarkPosX =  5;
                            _WatemarkPosY = (image.Height - copyImage.Height) / 2;
                        }

                        //居中
                        if (_WatemarkPos == 5)
                        {
                            _WatemarkPosX = (image.Width - copyImage.Width) / 2;
                            _WatemarkPosY = (image.Height - copyImage.Height) / 2;
                        }

                        //垂直居中水平靠右
                        if (_WatemarkPos == 6)
                        {
                            _WatemarkPosX = image.Width - copyImage.Width - 5;
                            _WatemarkPosY = (image.Height - copyImage.Height) / 2;
                        }

                        //左下角
                        if (_WatemarkPos == 7)
                        {
                            _WatemarkPosX = 5;
                            _WatemarkPosY = image.Height - copyImage.Height - 5;
                        }

                        //水平居中垂直底部
                        if (_WatemarkPos == 8)
                        {
                            _WatemarkPosX = (image.Width - copyImage.Width) / 2;
                            _WatemarkPosY = image.Height - copyImage.Height - 5;
                        }

                        //水印放置右上角
                        if (_WatemarkPos == 9)
                        {
                            _WatemarkPosX = image.Width - copyImage.Width - 5;
                            _WatemarkPosY = image.Height - copyImage.Height - 5;
                        }

                        if (copyImage.Height < image.Height && copyImage.Width < image.Width)
                        {
                            //将水印打印到上传图片上去
                            g.DrawImage(copyImage, new System.Drawing.Rectangle(_WatemarkPosX, _WatemarkPosY, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, System.Drawing.GraphicsUnit.Pixel);
                            //释放graphics
                            g.Dispose();
                        }
                        //保存图片
                        image.Save(_strFileFolder + strFileName);
                        //释放image
                        image.Dispose();
                    }

                }
                else
                {
                    UpLoadFile.PostedFile.SaveAs(_strFileFolder + strFileName);          //不加水印上传
                }

                //获得图片尺寸
                int OldFileHeight, OldFileWidth;
                System.Drawing.Image img = System.Drawing.Image.FromStream(UpLoadFile.PostedFile.InputStream);
                oldFileHeight = img.Height;
                oldFileWidth = img.Width;

                //创建缩略图
                if (_IsThumb == true)
                {
                    int NewImgHeight, NewImgWidth;

                    if (OldFileWidth > OldFileHeight)
                    {
                        NewImgWidth = _NewImgpx;
                        NewImgHeight = (int)(OldFileHeight / (float)OldFileWidth * _NewImgpx);
                    }
                    else
                    {
                        NewImgHeight = _NewImgpx;
                        NewImgWidth = (int)(OldFileWidth / (float)OldFileHeight * _NewImgpx);
                    }
                    //如果缩略图的尺寸大于原图尺寸，则用原图片大小
                    if (NewImgHeight >= OldFileHeight && NewImgWidth >= OldFileWidth)
                    {
                        NewImgHeight = OldFileHeight;
                        NewImgWidth = OldFileWidth;
                    }
                    System.Drawing.Image NewImg = img.GetThumbnailImage(NewImgWidth, NewImgHeight, null, System.IntPtr.Zero);
                    NewImg.Save(_strFileFolder + "Thumb_" + strFileName, System.Drawing.Imaging.ImageFormat.Jpeg);

                    //返回数据
                    _NewImgHeight = NewImgHeight;                 //缩略图高度
                    _NewImgWidth = NewImgWidth;                  //缩略图宽度
                    _thumbImgPath = _strNewFileFolder + "Thumb_" + strFileName;  //缩略图地址
                }
                //返回数据
                _OldFileWidth = OldFileWidth;    //原图宽度
                _OldFileHeight = OldFileHeight;  //原图高度

            }
        }

        this.OnUpload(this, e);

    }
}