做了个在上传图片的时候，自动修改图片大小的功能，其实一开始是想做类似京东商城的放大镜，然后发现做那样的需要相同的图片大小不同的的三张，于是想到是不是可以再上传图片的时候只上传一张，自动生成三张大小的图片，最后就做了这个功能！
#region 图片上传/// <summary>/// 图片上传0/// </summary>/// <returns></returns> private string Upload_Images0() { Boolean fileOK = false;string imageFile = ""; String path = Server.MapPath("~/adpic/"); //设置服务器上传的路径，即文件上传的位置 if (fulImage.PostedFile.ContentLength / 1024 < 2000) {if (fulImage.HasFile) {//获取上传文件类型 String fileExtension = System.IO.Path.GetExtension(fulImage.FileName).ToLower();//判断允许上传图片类型 String[] allowedExtensions = { ".gif", ".png", ".jpeg", ".jpg" };for (int i = 0; i < allowedExtensions.Length; i++) {if (fileExtension == allowedExtensions[i]) { fileOK = true;break; } }if (fileOK) {try {//把当前时间取出，组成字符串，加入文件名称，防止重复命名 string fileName = DateTime.Now.ToString().Replace("-", "").Replace(" ", "").Replace(":", "").Replace("/", "") + fulImage.FileName; fulImage.PostedFile.SaveAs(path + fileName); imageFile = "adpic/" + fileName;//自动生成小图 MakeThumNail(path + fileName, Server.MapPath("~/imagess/") + fileName, 600, 500, "W");//自动生成小图 MakeThumNail(path + fileName, Server.MapPath("~/image/") + fileName, 100, 50, "W");//自动生成中图 MakeThumNail(path + fileName, Server.MapPath("~/images/") + fileName, 200, 50, "W");//删除原图 System.IO.File.Delete(path + fileName); }catch (Exception e) { Response.Write("<script>alert('对不起，图片不能上传！')</script>"); } }else { Response.Write("<script>alert('对不起，不能接受这种文件类型！')</script>"); } } }else { Response.Write("<script>alert('对不起，图片过大不能上传！')</script>"); }return imageFile; }#endregion # region 图片处理/// <summary>/// 缩放图像/// </summary>/// <param name="originalImagePath">图片原始路径</param>/// <param name="thumNailPath">保存路径</param>/// <param name="width">缩放图的宽</param>/// <param name="height">缩放图的高</param>/// <param name="model">缩放模式</param> public static void MakeThumNail(string originalImagePath, string thumNailPath, int width, int height, string model) { System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);int thumWidth = width; //缩略图的宽度 int thumHeight = height; //缩略图的高度int x = 0;int y = 0;int originalWidth = originalImage.Width; //原始图片的宽度 int originalHeight = originalImage.Height; //原始图片的高度switch (model) {case "HW": //指定高宽缩放,可能变形 break;case "W": //指定宽度,高度按照比例缩放 thumHeight = originalImage.Height * width / originalImage.Width;break;case "H": //指定高度,宽度按照等比例缩放 thumWidth = originalImage.Width * height / originalImage.Height;break;case "Cut":if ((double)originalImage.Width / (double)originalImage.Height > (double)thumWidth / (double)thumHeight) { originalHeight = originalImage.Height; originalWidth = originalImage.Height * thumWidth / thumHeight; y = 0; x = (originalImage.Width - originalWidth) / 2; }else { originalWidth = originalImage.Width; originalHeight = originalWidth * height / thumWidth; x = 0; y = (originalImage.Height - originalHeight) / 2; }break;default:break; }//新建一个bmp图片 System.Drawing.Image bitmap = new System.Drawing.Bitmap(thumWidth, thumHeight);//新建一个画板 System.Drawing.Graphics graphic = System.Drawing.Graphics.FromImage(bitmap);//设置高质量查值法 graphic.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;//设置高质量，低速度呈现平滑程度 graphic.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//清空画布并以透明背景色填充 graphic.Clear(System.Drawing.Color.Transparent);//在指定位置并且按指定大小绘制原图片的指定部分 graphic.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, thumWidth, thumHeight), new System.Drawing.Rectangle(x, y, originalWidth, originalHeight), System.Drawing.GraphicsUnit.Pixel);try { bitmap.Save(thumNailPath, System.Drawing.Imaging.ImageFormat.Jpeg); }catch (Exception ex) {throw ex; }finally { originalImage.Dispose(); bitmap.Dispose(); graphic.Dispose(); } } # endregion
转载于:https://www.cnblogs.com/Kiss920Zz/archive/2011/12/26/2302223.html
