怎么用ASPX页面生成缩略图

最新推荐文章于 2009-04-02 00:04:00 发布

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此博客展示了一段C#代码，用于获取图片并进行缩放处理。代码通过接收请求中的宽高参数，对图片进行缩放，若未指定宽高则使用原图尺寸，最后将处理后的图片以JPEG格式输出。

using System;
using System.IO;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

public class GetImage : System.Web.UI.Page
{
private void Page_Load(object sender, System.EventArgs e)
{
  string strWidth = this.Request["width"];
  string strHeight = this.Request["height"];
  int width = -1, height = -1;
  try
  {
   width = Convert.ToInt32(strWidth);
   height = Convert.ToInt32(strHeight);
  }
  catch{}

  Response.ContentType = "image/JPEG";

  FileStream fs = new FileStream(@"c:/file1.jpg", FileMode.Open, FileAccess.Read);
  GetZoomedLogo(fs, width, height, this.Response);

  Response.End();

}

private void GetZoomedLogo(System.IO.Stream originLogo, int width, int height,System.IO.Stream outputStream)
{
int drawWidth = 0, drawHeight = 0;

System.Drawing.Image origin = System.Drawing.Image.FromStream(originLogo);

  if (width == 0 && height == 0)   //not designate width and height
  {
   width = origin.Width;
   height = origin.Height;
  }

  if (origin.Width < width && origin.Height < height)    //not zoom in
  {
   drawWidth = origin.Width;
   drawHeight = origin.Height;
  }
  else
  {
   double scaleX = (double)origin.Width / (double)width;
   double scaleY = (double)origin.Height / (double) height;

   double scale = scaleX > scaleY ? scaleX : scaleY;
   drawWidth = Convert.ToInt32(origin.Width / scale);
   drawHeight = Convert.ToInt32(origin.Height / scale);
  }
  System.Drawing.Rectangle destRect = new Rectangle((width - drawWidth) / 2, (height - drawHeight) / 2, drawWidth, drawHeight);

  Bitmap temp = new Bitmap(width, height);
  Graphics g = Graphics.FromImage(temp);

  SolidBrush brush = new SolidBrush(Color.White);
  g.FillRectangle(brush, 0, 0, width, height);             //draw background
//   g.DrawLine(new Pen(Color.Red, 10), 0, 0, 20, 20);

  if (width >= 300 || height >= 300)
  {
   g.DrawImage(origin, destRect);
  }
  else
  {
   System.Drawing.Image thumbnail = origin.GetThumbnailImage(drawWidth, drawHeight, null, System.IntPtr.Zero);
   g.DrawImage(thumbnail, destRect);
  }

temp.Save(outputStream, System.Drawing.Imaging.ImageFormat.Jpeg);

  origin.Dispose();
  temp.Dispose();
  g.Dispose();
}

}