一个.net 压缩位图至JPEG的实例代码

   
    <%@ Page language="c#" %>
    <%@ Import Namespace="System.Drawing" %>
    <%@ Import Namespace="System.Drawing.Imaging" %>

   

    <script language="c#" runat="server">

    private void Page_Load(object sender, System.EventArgs e)
    {

    // 设置 mime 类型为image/jpeg，即将向浏览器输出JPGE格式的图像
    Response.Clear();
    Response.ContentType="image/jpeg";

   
    Bitmap OutputBitmap = new Bitmap(Server.MapPath("source.bmp"));//新建BitMap对象
    System.Drawing.Imaging.EncoderParameters encoderParams = new System.Drawing.Imaging.EncoderParameters();
    long[] quality = new long[1];

    int comp = 0;
    if (Request.QueryString["comp"] != "") { comp = Convert.ToInt16(Request.QueryString["comp"]); }
    quality[0] = comp; //0 to 100 最高质量为100
    System.Drawing.Imaging.EncoderParameter encoderParam = new System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
    encoderParams.Param[0] = encoderParam;

    ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();//获得包含有关内置图像编码解码器的信息的ImageCodecInfo 对象 。
    ImageCodecInfo jpegICI = null;
    for (int x = 0; x < arrayICI.Length; x++)
    {
    if (arrayICI[x].FormatDescription.Equals("JPEG"))
    {
    jpegICI = arrayICI[x];//设置JPEG编码
    break;
    }
    }

    if (jpegICI != null)
    {
    OutputBitmap.Save(Response.OutputStream, jpegICI, encoderParams);//将位图对象以流格式并用JPEG编解码参数保存到输出流 。

    }

    // clean up
    OutputBitmap.Dispose();

    }
    </script>