// Copyright (C) 2003 by Greg Ennis
// (mailto:greg@ennis.net)
//
// The contents of this file are subject to the Artistic License (the "License").
// You may not use this file except in compliance with the License. 
// You may obtain a copy of the License at:
// http://www.opensource.org/licenses/artistic-license.html
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Web;
using System.IO;
using System.Configuration;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
namespace netpix
{
 public class ImageGenerator : IHttpHandler 
 { 
  public bool IsReusable 
  { get { return true; } } 
  public void ProcessRequest(HttpContext Context) 
  { 
   // Get the image filename and album root path from the database
   //图片浏览次数
   int numviews;
   //图片数据库中的ID
   int picid = Convert.ToInt32(Context.Request["id"]);
   //图片路径
   string imgpath = npdata.GetPathToPicture(picid, out numviews);
   // Writing an image to output stream
   Context.Response.ContentType = "image/jpg";
   // 'thumbnail' means we are requesting a thumbnail
   //显示缩略图
   if (Context.Request["thumbnail"] != null)
   {
    // Need to load the image, resize it, and stream to the client.
    // Calculate the scale so as not to stretch or distort the image.
    Bitmap bmp = new Bitmap(imgpath);
    float scale = 150.0f / System.Math.Max(bmp.Height, bmp.Width);
    System.Drawing.Image thumb = bmp.GetThumbnailImage((int)(bmp.Width * scale), (int)(bmp.Height * scale), null, System.IntPtr.Zero);
    thumb.Save(Context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
    bmp.Dispose();
    thumb.Dispose();
   }
   else
   {
    // Stream directly from the file
    // Get the stream and send it out the response
    System.IO.FileStream fs = File.Open(imgpath, FileMode.Open, FileAccess.Read, FileShare.Read);
    const int byteLength = 8192;
    byte[] bytes = new byte[byteLength];
    while( fs.Read(bytes, 0, byteLength ) != 0 )
    {
     Context.Response.BinaryWrite(bytes); 
    }
    fs.Close();
    //更新数据库浏览次数
    npdata.SetNumViews(picid, numviews+1);
   }
  }
 }
}