使用ASPJPEG组件生成缩略图

        /**//// <summary>
        /// 使用aspjpg生成缩略图
        /// </summary>
        /// <param name="OriginalPicPath">原图片路径，虚拟路径，如“images/aa.jpg”</param>
        /// <param name="thumbnailPicPath">缩略图保存路径，虚拟路径，如“images/”</param>
        /// <param name="maxWidth">缩略图最大宽度</param>
        /// <param name="maxHeight">缩略图最大高度</param>
        /// <returns>返回缩略图文件虚拟路径</returns>
        public string thumbPic(string OriginalPicPath,string thumbnailPicPath, int maxWidth,int maxHeight)
        {
            ASPJPEGLib.IASPJpeg objJpeg  = new ASPJPEGLib.ASPJpeg();

            // Compute path to source image
            String strPath = Server.MapPath(OriginalPicPath);            

            // Open source image
            objJpeg.Open( strPath );

            thumbnailPicPath += System.DateTime.Now.Date.ToShortDateString() + "." + System.DateTime.Now.Minute.ToString() + "." + System.DateTime.Now.Second.ToString() + "." + System.DateTime.Now.Millisecond.ToString() + "." + objJpeg.OriginalFormat; 

            //保证截取原图下缩略图成比例的原图
            decimal width=0;
            decimal height =0;
            if (objJpeg.OriginalWidth < objJpeg.OriginalHeight)
            {
                height = maxHeight;
                width =  Convert.ToInt32(maxHeight * objJpeg.OriginalWidth / objJpeg.OriginalHeight);
            }
            else
            {
                width = maxWidth;
                height = Convert.ToInt32(maxWidth * objJpeg.OriginalHeight/objJpeg.OriginalWidth);
            }

            objJpeg.Width = Convert.ToInt32(width);
            objJpeg.Height = Convert.ToInt32(height);

            // Create thumbnail and save it to disk
            objJpeg.Save(Server.MapPath(thumbnailPicPath));

            return thumbnailPicPath;
        }

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