這篇文章主要介紹了asp.net如何在圖片上加水印文字具體實現，有需要的朋友可以參考一下
第一步，添加一個一般處理程序（Handler）,本例是ImageHandler 代碼如下: using System; using System.Data; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.Net.Mime; using System.IO; using System.Drawing; using System.Drawing.Imaging; using System.Drawing.Drawing2D; /// <summary> /// Summary description for ImageHandler /// </summary> public class ImageHandler : IHttpHandler { public ImageHandler() { } public string GetContentType(String path) { switch (Path.GetExtension(path)) { case ".bmp": return "Image/bmp"; case ".gif": return "Image/gif"; case ".jpg": return "Image/jpeg"; case ".png": return "Image/png"; default: break; } return String.Empty; } public ImageFormat GetImageFormat(String path) { switch (Path.GetExtension(path).ToLower()) { case ".bmp": return ImageFormat.Bmp; case ".gif": return ImageFormat.Gif; case ".jpg": return ImageFormat.Jpeg; case ".png": return ImageFormat.Png; default: return null; } } protected byte[] WatermarkImage(HttpContext context) { byte[] imageBytes = null; if (File.Exists(context.Request.PhysicalPath)) { // Normally you'd put this in a config file somewhere. string watermark = "世復檢測"; Image image = Image.FromFile(context.Request.PhysicalPath); Graphics graphic; if (image.PixelFormat != PixelFormat.Indexed && image.PixelFormat != PixelFormat.Format8bppIndexed && image.PixelFormat != PixelFormat.Format4bppIndexed && image.PixelFormat != PixelFormat.Format1bppIndexed) { // Graphic is not a Indexed (GIF) image graphic = Graphics.FromImage(image); } else { /* Cannot create a graphics object from an indexed (GIF) image. * So we're going to copy the image into a new bitmap so * we can work with it. */ Bitmap indexedImage = new Bitmap(image); graphic = Graphics.FromImage(indexedImage); // Draw the contents of the original bitmap onto the new bitmap. graphic.DrawImage(image, 0, 0, image.Width, image.Height); image = indexedImage; } graphic.SmoothingMode = SmoothingMode.AntiAlias & SmoothingMode.HighQuality; Font myFont = new Font("Arial", 15); SolidBrush brush = new SolidBrush(Color.FromArgb(255, Color.Red)); /* This gets the size of the graphic so we can determine * the loop counts and placement of the watermarked text. */ SizeF textSize = graphic.MeasureString(watermark, myFont); //// Write the text across the image. //for (int y = 0; y < image.Height; y++) //{ // for (int x = 0; x < image.Width; x++) // { // PointF pointF = new PointF(x, y); // graphic.DrawString(watermark, myFont, brush, pointF); // x += Convert.ToInt32(textSize.Width); // } // y += Convert.ToInt32(textSize.Height); //} // Write the text at the right bottom of the image. for (int y = image.Height-25; y < image.Height; y++) { for (int x = image.Width-100; x < image.Width; x++) { PointF pointF = new PointF(x, y); graphic.DrawString(watermark, myFont, brush, pointF); x += Convert.ToInt32(textSize.Width); } y += Convert.ToInt32(textSize.Height); } using (MemoryStream memoryStream = new MemoryStream()) { image.Save(memoryStream, GetImageFormat(context.Request.PhysicalPath)); imageBytes = memoryStream.ToArray(); } } return imageBytes; } #region IHttpHandler Members public bool IsReusable { get { return false; } } public void ProcessRequest(HttpContext context) { context.Response.Clear(); context.Response.ContentType = GetContentType(context.Request.PhysicalPath); byte[] imageBytes = WatermarkImage(context); if (imageBytes != null) { context.Response.OutputStream.Write(imageBytes, 0, imageBytes.Length); } else { // No bytes = no image which equals NO FILE. // Therefore send a 404 - not found response. context.Response.StatusCode = 404; } context.Response.End(); } #endregion } 第二步，在web.config裡添加如下代碼： 代碼如下: <httpHandlers> <!--<add verb="GET" type="ImageHandler" path="*.jpg,*.png,*.gif,*.bmp"/>--> <add verb="GET" type="ImageHandler" path="Uploads/*/*.jpg"/> </httpHandlers>
