ASP.NET(C#)生成缩略图

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if (FileUpload1.PostedFile.ContentType.ToLower().IndexOf("image") < 0)
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{
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FunctionUtility.JavaScriptHelper.Alert("上传图片格式不正确！");
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return;
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}
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//生成原图
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Byte[] oFileByte = new Byte[FileUpload1.PostedFile.ContentLength];
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Stream oStream = FileUpload1.PostedFile.InputStream;
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System.Drawing.Image oImage = System.Drawing.Image.FromStream(oStream);
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//原图宽度和高度
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int oWidth = oImage.Width;
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int oHeight = oImage.Height;
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//设置缩略图的初始宽度和高度
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int tWidth = 200;
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int tHeight = 200;
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//按比例计算出缩略图的宽度和高度
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if (oWidth >= oHeight)
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{
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tHeight = (int)Math.Floor(Convert.ToDouble(oHeight) * (Convert.ToDouble(tWidth) / Convert.ToDouble(oWidth)));
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}
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else
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{
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tWidth = (int)Math.Floor(Convert.ToDouble(oWidth) * (Convert.ToDouble(tHeight) / Convert.ToDouble(oHeight)));
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}
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//生成缩略图
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Bitmap tImage = new Bitmap(tWidth, tHeight);
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Graphics g = Graphics.FromImage(tImage);
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//指定高质量插值法
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g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
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//指定高质量低速度呈现
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g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
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//清空画布并以透明背景色填充
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g.Clear(Color.Transparent);
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g.DrawImage(oImage, new Rectangle(0, 0, tWidth, tHeight), new Rectangle(0, 0, oWidth, oHeight), GraphicsUnit.Pixel);
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//设置文件名称
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string setFileName = FunctionUtility.FileHelper.GetDateTimeFileName()+".jpg";
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//保存原图的物理路径
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string oFullName = Server.MapPath("/DesignImages/Images/YT/" + setFileName);
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//保存缩略图物理路径
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string tFullName = Server.MapPath("/DesignImages/Images/SLT/" + setFileName);
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//以JPG格式保存图片并释放占用的资源
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try
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{
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oImage.Save(oFullName, System.Drawing.Imaging.ImageFormat.Jpeg);
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tImage.Save(tFullName, System.Drawing.Imaging.ImageFormat.Jpeg);
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Image1.Visible = true;
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Image2.Visible = true;
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Image1.ImageUrl = "/DesignImages/Images/YT/" + setFileName;
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Image2.ImageUrl = "/DesignImages/Images/SLT/" + setFileName;
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FunctionUtility.JavaScriptHelper.Alert("缩略图生成成功！");
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}
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catch (Exception oe)
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{
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throw oe;
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}
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finally
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{
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oImage.Dispose();
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g.Dispose();
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tImage.Dispose();
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}

Tag标签: ASP.NET,缩略图