WebSnap 网站截图,为什么有些站截出来的图是空白的.但从IE里面打开是正常的.附源代码

Question

/*
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 * 
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 */
using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Windows.Forms;namespace Snap
{
    public class GetImage
    {
        int S_Height;
        int S_Width;
        int F_Height;
        int F_Width;
        string MyURL;        public int ScreenHeight
        {
            get
            {
                return S_Height;
            }
            set
            {
                S_Height = value;
            }
        }        public int ScreenWidth
        {
            get
            {
                return S_Width;
            }
            set
            {
                S_Width = value;
            }
        }        public int ImageHeight
        {
            get
            {
                return F_Height;
            }
            set
            {
                F_Height = value;
            }
        }        public int ImageWidth
        {
            get
            {
                return F_Width;
            }
            set
            {
                F_Width = value;
            }
        }        public string WebSite
        {
            get
            {
                return MyURL;
            }
            set
            {
                MyURL = value;
            }
        }        public GetImage(string WebSite, int ScreenWidth, int ScreenHeight, int ImageWidth, int ImageHeight)
        {
            this.WebSite = WebSite;
            this.ScreenHeight = ScreenHeight;
            this.ScreenWidth = ScreenWidth;
            this.ImageHeight = ImageHeight;
            this.ImageWidth = ImageWidth;
        }        public  Bitmap GetBitmap()
        {
            WebPageBitmap Shot = new WebPageBitmap(this.WebSite, this.ScreenWidth, this.ScreenHeight);            Shot.GetIt();
            Bitmap Pic = Shot.DrawBitmap(this.ImageHeight, this.ImageWidth);
            return Pic;
        }
    }    public class WebPageBitmap
    {
        WebBrowser MyBrowser;
        string URL;
        int Height;
        int Width;        public  WebPageBitmap(string url, int width, int height)
        {
            this.URL = url;
            this.Width = width;
            this.Height = height;
            MyBrowser = new WebBrowser();
            MyBrowser.ScrollBarsEnabled = false;
            MyBrowser.Size = new Size(this.Width, this.Height);
        }        public void GetIt()
        {
            MyBrowser.Navigate(this.URL);
            while (MyBrowser.ReadyState != WebBrowserReadyState.Complete)
            {
                Application.DoEvents();
            }
        }        public Bitmap DrawBitmap(int theight, int twidth)
        {
            Bitmap myBitmap = new Bitmap(this.Width, this.Height);
            Rectangle DrawRect = new Rectangle(0, 0, this.Width, this.Height);
            MyBrowser.DrawToBitmap(myBitmap, DrawRect);
            System.Drawing.Image imgOutput = myBitmap;
            System.Drawing.Bitmap oThumbNail = new Bitmap(twidth, theight, imgOutput.PixelFormat);
            Graphics g = Graphics.FromImage(oThumbNail);            g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighSpeed;
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighSpeed;
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBilinear;            Rectangle oRectangle = new Rectangle(0, 0, twidth, theight);
            g.DrawImage(imgOutput, oRectangle);            try
            {
                return oThumbNail;
            }
            catch
            {
                return null;
            }
            finally
            {
                imgOutput.Dispose();
                imgOutput = null;
                MyBrowser.Dispose();
                MyBrowser = null;
            }        }
    }
}
下面是调用代码:
            string url = string.Empty;
            url = Request.QueryString[0];
            try
            {
                GetImage thumb = new GetImage(url, 1024, 768, 320, 240);
                System.Drawing.Bitmap x = thumb.GetBitmap();
                x.Save(Response.OutputStream, ImageFormat.Jpeg);
                Response.ContentType = "image/jpeg";
            }
            catch
            {
                
            }       
有的站截出来的图是空白的.不知道是哪里问题.谁来解决一下,谢谢.
目前发现是空白的站有:
http://m.iask.com/
http://mp3.sogou.com/

Answer 1

我知道了,你的代码是必须要知道具体的页面,比如http://www.yahoo.com.cn/不行,必须是http://www.aa.con/aa.aspx,这样子的

Answer 2

代码太多...不过
 x.Save(Response.OutputStream, ImageFormat.Jpeg);
                Response.ContentType = "image/jpeg";
这两个顺序要倒一下吧

Answer 3

试了下,楼主的代码用了WebBrowser控件,这个东西web使用麻烦啊,必须在单线程使用

Answer 4

不用的,比如www.baidu.com和www.qq.com都是可以的.

Answer 5

不说了,代码说话
改后的是
using System.Windows.Forms;
using System.Drawing;
using System.Net;
using mshtml;
using System.Reflection;
using System.Runtime.InteropServices;
using System;
using System.Drawing.Drawing2D;

Answer 6

代码说话
using System.Windows.Forms;
using System.Drawing;
using System.Net;
using mshtml;
using System.Reflection;
using System.Runtime.InteropServices;
using System;
using System.Drawing.Drawing2D;namespace WebImage
{
    [InterfaceType(1)]
    [Guid("3050F669-98B5-11CF-BB82-00AA00BDCE0B")]
    public interface IHTMLElementRender2
    {
        void DrawToDC(IntPtr hdc);
        void SetDocumentPrinter(string bstrPrinterName, ref _RemotableHandle hdc);
    }    public class GetImage
    {
        private string MyURL;
        private int Browser_Height;
        private int Browser_Width;
        private int Img_Height;
        private int Img_Width;        public int BrowserHeight
        {
            get
            {
                return Browser_Height;
            }
            set
            {
                Browser_Height = value;
            }
        }        public int BrowserWidth
        {
            get
            {
                return Browser_Width;
            }
            set
            {
                Browser_Width = value;
            }
        }        public int ImageHeight
        {
            get
            {
                return Img_Height;
            }
            set
            {
                Img_Height = value;
            }
        }        public int ImageWidth
        {
            get
            {
                return Img_Width;
            }
            set
            {
                Img_Width = value;
            }
        }        public string WebUrl
        {
            get
            {
                return MyURL;
            }
            set
            {
                MyURL = value;
            }
        }        /// <summary>
        /// 主要是得到参数
        /// </summary>
        /// <param name="WebSite"></param>
        /// <param name="ScreenWidth"></param>
        /// <param name="ScreenHeight"></param>
        /// <param name="ImageWidth"></param>
        /// <param name="ImageHeight"></param>
        public GetImage(string WebSite, int ScreenWidth, int ScreenHeight, int ImageWidth, int ImageHeight)
        {
            this.WebUrl = WebSite;
            this.BrowserHeight = ScreenHeight;
            this.BrowserWidth = ScreenWidth;
            this.ImageHeight = ImageHeight;
            this.ImageWidth = ImageWidth;
        }        public Bitmap GetBitmap()
        {
            WebPageBitmap Shot = new WebPageBitmap(this.WebUrl, this.BrowserWidth, this.BrowserHeight);
            if (Shot.IsOk)
            {
                Shot.GetImg();
                Bitmap Pic = Shot.DrawBitmap(this.ImageHeight, this.ImageWidth);
                return Pic;
            }
            else
            {
                MessageBox.Show(Shot.ErrorMessage);
            }            return new Bitmap(100, 100);
        }
    }

Answer 7

 public class WebPageBitmap
    {
        private WebBrowser webBrowser;
        private string URL;
        private int Height;
        private int Width;
        private bool isOk;
        private string errorMessage;        public string ErrorMessage
        {
            get { return errorMessage; }
        }        public bool IsOk
        {
            get { return isOk; }
            set { isOk = value; }
        }        public WebPageBitmap(string url, int width, int height)
        {
            this.Width = width;
            this.Height = height;            this.URL =
                url.StartsWith("http://", StringComparison.InvariantCultureIgnoreCase) ?
                url : this.URL = "http://" + url;            try
            // needed as the script throws an exeception if the host is not found
            {
                HttpWebRequest req = (HttpWebRequest)WebRequest.Create(this.URL);
                req.AllowAutoRedirect = true;
                req.UserAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 3.0.04506; .NET CLR 3.5.21022; .NET CLR 1.0.3705; .NET CLR 1.1.4322)";
                //req.Referer = "http://www.cognifide.com"; //这一句应该是告诉服务器我是从哪个页面链接过来的
                req.ContentType = "text/html";
                req.Accept = "*/*";
                req.KeepAlive = false;                using (HttpWebResponse resp = (HttpWebResponse)req.GetResponse())
                {
                    string x = resp.StatusDescription;
                }            }
            catch (Exception ex)
            {
                errorMessage = ex.Message;
                isOk = false;
                return;
            }
            isOk = true;    
         // public, to check in program.cs if the domain is found, so the image can be saved            webBrowser = new WebBrowser();
            webBrowser.Size = new Size(this.Width, this.Height);
            webBrowser.ScrollBarsEnabled = false;
            webBrowser.DocumentCompleted +=
            new WebBrowserDocumentCompletedEventHandler(documentCompletedEventHandler);        }        /// <summary>
        /// Fetches the image 
        /// </summary>
        /// <returns>true is the operation ended with a success</returns>
        public bool GetImg()
        {
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(URL);
            req.AllowAutoRedirect = true;
            req.UserAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 3.0.04506; .NET CLR 3.5.21022; .NET CLR 1.0.3705; .NET CLR 1.1.4322)";
            // req.Referer = "http://www.cognifide.com";//同上面的注释
            req.ContentType = "text/html";
            req.AllowWriteStreamBuffering = true;
            req.AutomaticDecompression = DecompressionMethods.GZip;
            req.Method = "GET";
            req.Proxy = null;
            req.ReadWriteTimeout = 20;            HttpStatusCode status;
            using (HttpWebResponse resp = (HttpWebResponse)req.GetResponse())
            {
                status = resp.StatusCode;
            }            if (status == HttpStatusCode.OK || status == HttpStatusCode.Moved)
            {
                webBrowser.Navigate(URL);
                while (webBrowser.ReadyState != WebBrowserReadyState.Complete)
                {
                    Application.DoEvents();                }
                return true;
            }
            else
            {
                return false;
            }
        }        private void documentCompletedEventHandler(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            ((WebBrowser)sender).Document.Window.Error +=
                new HtmlElementErrorEventHandler(SuppressScriptErrorsHandler);
        }        public void SuppressScriptErrorsHandler(object sender, HtmlElementErrorEventArgs e)
        {
            e.Handled = true;
            MessageBox.Show("Error!");
        }        internal Bitmap DrawBitmap(int thumbwidth, int thumbheight)
        {
            
            IHTMLDocument2 rawDoc = (IHTMLDocument2)webBrowser.Document.DomDocument;
            IHTMLElement rawBody = rawDoc.body;
            IHTMLElementRender2 render = (IHTMLElementRender2)rawBody;            Bitmap bitmap = new Bitmap(Width, Height);
            Rectangle bitmapRect = new Rectangle(0, 0, Width, Height);            // Interesting thing that despite using the renderer later 
            // this following line is still necessary or 
            // the background may not be painted on some websites.
            webBrowser.DrawToBitmap(bitmap, bitmapRect);            using (Graphics graphics = Graphics.FromImage(bitmap))
            {
                IntPtr graphicshdc = graphics.GetHdc();
                render.DrawToDC(graphicshdc);                graphics.ReleaseHdc(graphicshdc);
                graphics.Dispose();                if (thumbheight == Height && thumbwidth == Width)
                {
                    return bitmap;
                }
                else
                {
                    Bitmap thumbnail = new Bitmap(thumbwidth, thumbheight);
                    using (Graphics gfx = Graphics.FromImage(thumbnail))
                    {
                        // high quality image sizing
                        gfx.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                        gfx.InterpolationMode = InterpolationMode.HighQualityBicubic;                                                                       // make it look pretty 
                        gfx.DrawImage(bitmap, new Rectangle(0, 0, thumbwidth, thumbheight), bitmapRect, GraphicsUnit.Pixel);
                    }
                    bitmap.Dispose();
                    return thumbnail;
                }
            }
        }
    }
}
这是改成你上面风格的代码

Answer 8

原文地址http://www.codeproject.com/KB/cs/Website_Thumbnails_in_C.aspxHow To Get A Website Thumbnail in a C# Application Without Creating A Form (console)

昨天看到你发这个,觉得很有意思,就看了一下,只是看了别人的代码,不好意思,只能给你提供地址,一起研究