using System; using System.Configuration; using System.Drawing; using System.IO; using System.Web; namespace BLL { public static class UpLoadImageService { /// <summary> /// asp.net上传图片并生成缩略图 /// </summary> /// <param name="myFile">文件</param> /// <param name="sSavePath">保存的路径,些为相对服务器路径的下的文件夹</param> /// <param name="sThumbExtension">缩略图的thumb</param> /// <param name="intThumbWidth">生成缩略图的宽度</param> /// <param name="intThumbHeight">生成缩略图的高度</param> /// <returns></returns> public static string UpLoadImage(HttpPostedFile myFile, string sSavePath, string sThumbExtension, int intThumbWidth, int intThumbHeight) { string sThumbFile = ""; string sFilename = ""; int nFileLen = myFile.ContentLength; if (nFileLen == 0) { return "没有选择上传图片"; } //获取upImage选择文件的扩展名 string extendName = Path.GetExtension(myFile.FileName).ToLower(); //判断是否为图片格式 if (extendName != ".jpg" && extendName != ".jpge" && extendName != ".gif" && extendName != ".bmp" && extendName != ".png") { return "图片格式不正确"; } byte[] myData = new Byte[nFileLen]; myFile.InputStream.Read(myData, 0, nFileLen); sFilename = SQLHelper.GetNewID(); string localRoot = ConfigurationManager.AppSettings["localRoot"]; string bigPath = localRoot + sSavePath;//物理路径 if (!Directory.Exists(bigPath)) { Directory.CreateDirectory(bigPath); } FileStream newFile = new FileStream(bigPath + sFilename+ extendName, FileMode.Create, FileAccess.Write); newFile.Write(myData, 0, myData.Length); newFile.Close(); //以上为上传原图 try { //原图加载 using (Image sourceImage = Image.FromFile(bigPath + sFilename + extendName)) { //原图宽度和高度 int width = sourceImage.Width; int height = sourceImage.Height; int smallWidth; int smallHeight; //获取第一张绘制图的大小,(比较 原图的宽/缩略图的宽 和 原图的高/缩略图的高) if (((decimal)width) / height <= ((decimal)intThumbWidth) / intThumbHeight) { smallWidth = intThumbWidth; smallHeight = intThumbWidth * height / width; } else { smallWidth = intThumbHeight * width / height; smallHeight = intThumbHeight; } string localRoots = localRoot + sThumbExtension; if (!Directory.Exists(localRoots)) { Directory.CreateDirectory(localRoots); } //判断缩略图在当前文件夹下是否同名称文件存在 sThumbFile = localRoots + SQLHelper.GetNewID() + extendName; //缩略图保存的绝对路径 string smallImagePath = sThumbFile; //新建一个图板,以最小等比例压缩大小绘制原图 using (Image bitmap = new Bitmap(smallWidth, smallHeight)) { //绘制中间图 using (Graphics g = Graphics.FromImage(bitmap)) { //高清,平滑 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; g.Clear(Color.Black); g.DrawImage( sourceImage, new System.Drawing.Rectangle(0, 0, smallWidth, smallHeight), new System.Drawing.Rectangle(0, 0, width, height), System.Drawing.GraphicsUnit.Pixel ); } //新建一个图板,以缩略图大小绘制中间图 using (System.Drawing.Image bitmap1 = new System.Drawing.Bitmap(intThumbWidth, intThumbHeight)) { //绘制缩略图 using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap1)) { //高清,平滑 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; g.Clear(Color.Black); int lwidth = (smallWidth - intThumbWidth) / 2; int bheight = (smallHeight - intThumbHeight) / 2; g.DrawImage(bitmap, new Rectangle(0, 0, intThumbWidth, intThumbHeight), lwidth, bheight, intThumbWidth, intThumbHeight, GraphicsUnit.Pixel); g.Dispose(); bitmap1.Save(smallImagePath, System.Drawing.Imaging.ImageFormat.Jpeg); } } } } } catch (Exception ex) { //出错则删除 File.Delete(localRoot + sFilename); return "图片格式不正确"; } //返回缩略图名称 return sThumbFile; } } }