如何用ASP.NET制作图片缩略图并添加水印？

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本示例展示了如何使用ASP.NET生成缩略图，并为原始图像添加水印。

csharpusing System.IO;using System.Drawing.Imaging;

private void Button1_ServerClick(object sender, System.EventArgs e){ string originalImagePath=@C:\path\to\your\image.jpg; // 原始图像路径 string thumbnailPath=@C:\path\to\your\thumbnail.jpg; // 缩略图路径

// 加载原始图像 using (System.Drawing.Image originalImage=System.Drawing.Image.FromFile(originalImagePath)) { // 创建缩略图 using (System.Drawing.Image thumbnailImage=originalImage.GetThumbnailImage(100, 100, null, IntPtr.Zero)) { // 保存缩略图 thumbnailImage.Save(thumbnailPath, ImageFormat.Jpeg); }

// 创建水印文本 using (System.Drawing.Graphics graphics=System.Drawing.Graphics.FromImage(originalImage)) { using (System.Drawing.Font font=new System.Drawing.Font(Arial, 20)) { using (System.DrawingBrush brush=new System.Drawing.SolidBrush(System.Drawing.Color.Red)) { // 设置水印位置 graphics.DrawString(Watermark, font, brush, new System.Drawing.Point(50, 50)); } }

// 保存添加水印的图像 originalImage.Save(originalImagePath, ImageFormat.Jpeg); } }}

本文实例讲述了asp.net实现生成缩略图及给原始图加水印的方法。分享给大家供大家参考，具体如下：

using System.IO; using System.Drawing.Imaging; private void Button1_ServerClick(object sender, System.EventArgs e) { Graphics g=null; System.Drawing.Image upimage=null; System.Drawing.Image thumimg=null; System.Drawing.Image simage=null; Bitmap outputfile=null; try { string extension = Path.GetExtension(File1.PostedFile.FileName).ToUpper(); string filename = DateTime.Now.ToString("yyyyMMddhhmmss"); string smallpath = Server.MapPath(".")+"/smallimg/"; string bigpath = Server.MapPath(".")+"/bigimg/"; int width,height,newwidth,newheight; System.Drawing.Image.GetThumbnailImageAbort callb =new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback); if(!Directory.Exists(smallpath)) Directory.CreateDirectory(smallpath); if(!Directory.Exists(bigpath)) Directory.CreateDirectory(bigpath); Stream upimgfile = File1.PostedFile.InputStream; string simagefile = Server.MapPath("a8logo.jpg"); //要加水印的文件 simage=System.Drawing.Image.FromFile(simagefile); upimage= System.Drawing.Image.FromStream(upimgfile); //上传的图片 width = upimage.Width; height = upimage.Height; if(width>height) { newwidth=200; newheight =(int)((double)height/(double)width * (double)newwidth); } else { newheight=200; newwidth=(int)((double)width/(double)height * (double)newheight); } thumimg = upimage.GetThumbnailImage(newwidth,newheight,callb,IntPtr.Zero); outputfile=new Bitmap(upimage); g=Graphics.FromImage(outputfile); g.DrawImage(simage,new Rectangle(upimage.Width-simage.Width,upimage.Height-simage.Height,upimage.Width,upimage.Height),0,0,upimage.Width,upimage.Height,GraphicsUnit.Pixel); string newpath = bigpath + filename + extension; //原始图路径 string thumpath = smallpath + filename + extension; //缩略图路径 outputfile.Save(newpath); thumimg.Save(thumpath); outputfile.Dispose(); } catch(Exception ex) { throw ex; } finally { if(g!=null) g.Dispose(); if(thumimg!=null) thumimg.Dispose(); if(upimage!=null) upimage.Dispose(); if(simage!=null) simage.Dispose(); } } public bool ThumbnailCallback() { return false; }

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希望本文所述对大家asp.net程序设计有所帮助。