在網站開發中,經常會使用一些文本編輯控件，如CuteEditor。這些控件一般都能同時輸入文本和圖片，并進行圖文混排。如何讀取該文本框中的圖片路徑，并生成縮略圖，是很多開發者頭疼的事情。本文根據網絡資料進行整理，現將完整代碼呈現如下：
 
1、獲取圖片地址：
 
       /// <summary>
        /// 通過正則表達式獲取圖片地址。
        /// </summary>
        /// <param name="RegExpress">正則表達式</param>
        /// <param name="InputString">源字符串</param>
        /// <returns></returns>
        //RegExpress為要匹配的正則表達式，InputString為源字符串。
        public string GetImageUrl(string RegExpress, string InputString)
        {
            //RegExpress為正則表達式，例如，獲取圖片URL的正則表達式為： regstring ="(?<=src=\").+?\\.(gif|jpg|bmp|png)(?=\")"
            Regex re = new Regex(RegExpress, RegexOptions.IgnoreCase|RegexOptions.Compiled);
           
            Match ma = re.Match(InputString);
            if (ma.Success)
            {
                return  ma.Value.Substring(1);
            }
            else
            {
                return "";
            }
        }
 
2、生成縮略圖
 
        /// <summary>
        /// 生成縮略圖
        /// </summary>
        /// <param name="originalImagePath">源圖路徑（物理路徑）</param>
        /// <param name="thumbnailPath">縮略圖路徑（物理路徑）</param>
        /// <param name="width">縮略圖寬度</param>
        /// <param name="height">縮略圖高度</param>
        /// <param name="mode">生成縮略圖的方式</param>   
        public void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
        {
            Image originalImage = Image.FromFile(originalImagePath);
 
            int towidth = width;
            int toheight = height;
 
            int x = 0;
            int y = 0;
            int ow = originalImage.Width;
            int oh = originalImage.Height;
 
            switch (mode)
            {
                case "HW"://指定高寬縮放（可能變形）               
                    break;
                case "W"://指定寬，高按比例                   
                    toheight = originalImage.Height * width / originalImage.Width;
                    break;
                case "H"://指定高，寬按比例
                    towidth = originalImage.Width * height / originalImage.Height;
                    break;
                case "Cut"://指定高寬裁減（不變形）               
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                    {
                        oh = originalImage.Height;
                        ow = originalImage.Height * towidth / toheight;
                        y = 0;
                        x = (originalImage.Width - ow) / 2;
                    }
                    else
                    {
                        ow = originalImage.Width;
                        oh = originalImage.Width * height / towidth;
                        x = 0;
                        y = (originalImage.Height - oh) / 2;
                    }
                    break;
                default:
                    break;
            }
 
            //新建一個bmp圖片
            Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
 
            //新建一個畫板
            Graphics g = System.Drawing.Graphics.FromImage(bitmap);
 
            //設置高質量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
 
            //設置高質量,低速度呈現平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
 
            //清空畫布并以透明背景色填充
            g.Clear(Color.Transparent);
 
            //在指定位置并且按指定大小繪制原圖片的指定部分
            g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
                new Rectangle(x, y, ow, oh),
                GraphicsUnit.Pixel);
 
            try
            {
                //以jpg格式保存縮略圖
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            //catch (System.Exception e)
            //{
            //    throw e;
            //}
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }
 
3、獲取縮略圖相對路徑
 
        /// <summary>
        /// 獲取縮略圖路徑.
        /// </summary>
        /// <param name="InputString">帶有圖像標簽的文本</param>
        /// <returns>縮略圖全路徑</returns>
        public string GetTitleImageUrl(string InputString)
        {
            string RegString = "(?<=src=\").+?\\.(gif|jpg|bmp)(?=\")";
            string ImageUrl = GetImageUrl(RegString, InputString);
            string ImageDirectory = System.IO.Path.GetDirectoryName(ImageUrl);
            string ImageFileName = System.IO.Path.GetFileName(ImageUrl);
            string ReturnImageUrl = ImageDirectory + "/t" + ImageFileName;//返回的縮略圖的相對路徑
            string InputImageUrl = System.Web.HttpContext.Current.Server.MapPath("~/"+ImageUrl);//源圖物理路徑
            string OutputImageUrl = System.Web.HttpContext.Current.Server.MapPath("~/"+ImageDirectory+"/t"+ImageFileName);//縮略圖物理路徑
            int width = 160;//縮略圖寬
            int height = 190;//縮略圖高
            string mode = "H";//縮放模式
            MakeThumbnail(InputImageUrl, OutputImageUrl, width, height, mode);
            return ReturnImageUrl;
        }

本文來自CSDN博客，轉載請標明出處：http://blog.csdn.net/z365days/archive/2007/04/26/1585726.aspx