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[转].net 缩略图方法
本文转自:http://www.cnblogs.com/promic/archive/2010/04/21/1717190.html
private static string strConnect = System.Configuration.ConfigurationManager.AppSettings["connStr"]; //上传图像 protected void btnUpload_Click(object sender, EventArgs e) { …… string imgType; string fullFileName = this.txtPath.PostedFile.FileName; imgType = fullFileName.Substring(fullFileName.LastIndexOf(".") + 1).ToLower(); string UserDirectory = Session["UserID"].ToString();//用户ID为所创建文件夹的名字 string UserPath = Server.MapPath("UpLoad").ToString() + "\\" + UserDirectory; //如果文件夹不存在则创建 if (!Directory.Exists(UserPath)) { Directory.CreateDirectory(UserPath); } string originalImagePath = UserPath + "\\" + "Original"; if(!Directory.Exists(originalImagePath)) { Directory.CreateDirectory(originalImagePath); } string thumbnailPath = UserPath + "\\" + "Thumbnail"; if (!Directory.Exists(thumbnailPath)) { Directory.CreateDirectory(thumbnailPath); } // 获取上传图像的文件名 string fileName = txtName.Text; …… if (imgType=="jpg"||imgType=="jpeg"||imgType=="bmp"||imgType=="png"||imgType=="icon") { try { //生成原图 byte[] oFileByte = new byte[this.txtPath.PostedFile.ContentLength]; Stream oStream = this.txtPath.PostedFile.InputStream; System.Drawing.Image oImage = System.Drawing.Image.FromStream(oStream); int oWidth = oImage.Width;//原图宽度 int oHeight = oImage.Height;//原图高度 int tWidth = 100;//设置缩略图初始宽度 int tHeight = 100;//设置缩略图初始宽度 //按比例计算出缩略图的宽度和高度 if (oWidth >= oHeight) { tHeight = (int)Math.Floor(Convert.ToDouble(oHeight) * (Convert.ToDouble(tWidth) / Convert.ToDouble(oHeight))); } else { tWidth = (int)Math.Floor(Convert.ToDouble(oWidth) * (Convert.ToDouble(tHeight) / Convert.ToDouble(oHeight))); } //生成缩略图 Bitmap tImage = new Bitmap(tWidth,tHeight); Graphics g = Graphics.FromImage(tImage); g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;//设置高质量插值法 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度 g.Clear(Color.Transparent);//清空画布并以透明背景色填充 g.DrawImage(oImage, new Rectangle(0, 0, tWidth, tHeight), new Rectangle(0, 0, oWidth, oHeight), GraphicsUnit.Pixel); //this.txtPath.PostedFile.SaveAs(originalImagePath + "\\" + fileName + "." + imgType); //string originalImageUrl = "UpLoad/" + UserDirectory + "/" + "Orginal/"+fileName + ".jpg" ;//得到服务端原图片的虚拟路径 // string thumbnailImageUrl = "UpLoad/" + UserDirectory + "/" + "Thumbnail/" + fileName + ".jpg";//得到服务端原图片的虚拟路径 //以JPG格式保存图像 //oImage.Save(originalImageUrl, System.Drawing.Imaging.ImageFormat.Jpeg);/*看看这里这两个保存方式有没有问题*/ // tImage.Save(thumbnailImageUrl, System.Drawing.Imaging.ImageFormat.Jpeg); string oPath = originalImagePath + "\\" + fileName + ".jpg"; string tPath = thumbnailPath + "\\" + fileName + ".jpg"; //以JPG格式保存图像 oImage.Save(oPath, System.Drawing.Imaging.ImageFormat.Jpeg); tImage.Save(tPath, System.Drawing.Imaging.ImageFormat.Jpeg); lblMessage.Visible = true; lblMessage.Text = "图像上传成功!"; txtName.Text = ""; txtDescription.Text = ""; //释放资源 oImage.Dispose(); g.Dispose(); tImage.Dispose(); } catch (Exception ex) { lblMessage.Visible = true; lblMessage.Text = "由于网络原因,上载文件错误 " + ex.Message; } } else { Response.Write("<script language=‘javascript‘>alert(‘你选择的图像格式错误!‘);</script>"); lblMessage.Visible = false; } }
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