第一步,添加一个一般处理程序(Handler),本例是ImageHandler
复制代码 代码如下: 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 = "世复检测";
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里添加如下代码:
复制代码 代码如下: <httpHandlers> <!--<add verb="GET" type="ImageHandler" path="*.jpg,*.png,*.gif,*.bmp"/>--> <add verb="GET" type="ImageHandler" path="Uploads/*/*.jpg"/> </httpHandlers>
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