一个《将上传的图片增加水印及生成缩略图》的C#操作类

using System;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;


namespace XdCMS.UI.Image
{
    /**//// <summary>
    ///将上传的图片增加水印及生成缩略图
    /// </summary>
    public class ThumImage
    {
        /**//// <summary>
        /// 水印图
        /// </summary>
        public Bitmap LogoImage
        {
            get{return this._logoImage;}
        }
        /**//// <summary>
        /// 缩略图
        /// </summary>
        public Bitmap ThumbImage
        {
            get{return this._thumbImage;}
        }
        /**//// <summary>
        /// 叠加在图片上的文字
        /// </summary>
        public string TextImage
        {
            get{return this._textImage;}
            set{this._textImage=value ;}
        }
        /**//// <summary>
        /// 上传的图片流
        /// </summary>
        public Stream Upstream
        {
            get{ return this._upstream;}
            set{this._upstream = value;}
        }

        public string LogoFile
        {
            get{ return this._logoFile;}
            set{this._logoFile = value;}
        }  
        public int PicWidth
        {
            get{ return this._picwidth;}    
        }


        private Bitmap _logoImage;
        private Bitmap _thumbImage;
        private string _textImage;
        private Stream _upstream;
  
        private string _logoFile;
        private int _picwidth;

        /**//// <summary>
        /// 生成水印图
        /// </summary>
        /// <param name="txtImage">版权信息</param>
        /// <param name="upstream">上传文件流</param>
        /// <param name="logofile">水印图Logo的绝对路径</param>
        public ThumImage(string txtImage,Stream upstream,string logofile)
        {
            this.TextImage = txtImage;
            this.Upstream = upstream;
            this._logoFile = logofile;
            AddLogoPic();     
        }
        /**//// <summary>
        /// 生成水印图和缩略图
        /// </summary>
        /// <param name="txtImage">版权信息</param>
        /// <param name="upstream">上传文件流</param>
        /// <param name="logofile">水印图Logo的绝对路径</param>
        /// <param name="picwidth">缩略图的大小</param>
        public ThumImage(string txtImage,Stream upstream,string logofile,int picwidth)
        {
            this.TextImage = txtImage;
            this.Upstream = upstream;
            this._logoFile = logofile;
            this._picwidth = picwidth;
            AddLogoPic();
            BuildThumbPic();
        }

        /**//// <summary>
        /// 加水印
        /// </summary>
        private void AddLogoPic()
        {   
            try
            {
                System.Drawing.Image upimage = System.Drawing.Image.FromStream(this.Upstream);
                System.Drawing.Image simage = System.Drawing.Image.FromFile(this.LogoFile);

                //logo上填充文字
                Bitmap bitlogo=new Bitmap(simage);
                Graphics sg= Graphics.FromImage(bitlogo);
                Font textFont = new Font("arial",8);
                RectangleF rectangle = new RectangleF(0,51,simage.Width,14);
                StringFormat StrFormat = new StringFormat();
                StrFormat.Alignment = StringAlignment.Far;

                sg.DrawString(this.TextImage,textFont,new SolidBrush(Color.FromArgb(153, 0, 0, 0)), rectangle,StrFormat);
                SolidBrush semiTransBrush = new SolidBrush(Color.FromArgb(153, 255, 255, 255)); //设透明字体
                sg.DrawString(this.TextImage,textFont,semiTransBrush, rectangle,StrFormat);
                sg.Flush();     

                Bitmap bitimage = new Bitmap(upimage);     
                Graphics g = Graphics.FromImage(bitimage);
                g.DrawImage(bitlogo,new Rectangle(upimage.Width-simage.Width,upimage.Height-simage.Height,upimage.Width,upimage.Height),0,0,upimage.Width,upimage.Height,GraphicsUnit.Pixel);
                g.Flush();
                this._logoImage =bitimage;
                bitlogo.Dispose();
                upimage.Dispose();
                simage.Dispose();
   
            }
            catch(Exception ex)
            {
                throw ex;
            }
        }
        /**//// <summary>
        /// 生成缩略图
        /// </summary>
        private void BuildThumbPic()
        {
            try
            {
                    int width,height,newwidth,newheight;
                System.Drawing.Image upimage = System.Drawing.Image.FromStream(this.Upstream);
                System.Drawing.Image simage = System.Drawing.Image.FromFile(this.LogoFile);
                width = upimage.Width;
                height = upimage.Height;
                if(width>height)
                {
                    newwidth=this.PicWidth;
                    newheight =(int)((double)height/(double)width * (double)newwidth);
                }
                else
                { 
                    newheight=this.PicWidth;
                    newwidth=(int)((double)width/(double)height * (double)newheight);   
                }
                if (newwidth <= 0)
                    throw new ArgumentOutOfRangeException("width", newwidth, "缩略图片宽度不能为0");
                if (newheight <= 0)
                    throw new ArgumentOutOfRangeException("height", newheight, "缩略图片高度不能为0");

                this._thumbImage =new Bitmap(upimage.GetThumbnailImage(newwidth,newheight,null,IntPtr.Zero)); 
                upimage.Dispose();
                simage.Dispose();
            }
            catch(Exception ex)
            {
                throw ex;
            } 
   
        }

        ~ThumImage()
        {
            Dispose(false);
        }
  
        public void Dispose()
        {
            GC.SuppressFinalize(this);
            this.Dispose(true);
        }
        protected virtual void Dispose(bool disposing)
        {
            if (disposing) 
            {
                if(this._logoImage!=null)
                    this._logoImage.Dispose();
                if(this._thumbImage!=null)
                    this._thumbImage.Dispose();
            }
        }

  

    }
}