如何将网页保存为图像

Question

我有一个 WebBrowser 控件，我想将查看的整个页面保存到图像（任何网页）。 我尝试使用 IHTMLElementRender 接口，但它不适用于所有网页。 也许我做错了什么，因为有时快照包含滚动条，有时只是部分的。 您是否有一个可以将整个网页保存为图像的工作示例？

谢谢。

Answer 1

有一篇 很棒的 CodeProject 文章，展示了如何使用 IE 完成此任务引擎。 如果您更喜欢使用其他浏览器的渲染引擎，那么这是一个开始学习的好地方。 还有一个用于 Firefox 的 一个插件 可以做到这一点，你可以深入研究它的内部结构，深入了解如何在 Firefox 中实现这一目标。

Answer 2

您可以使用这些人 http://webthumb.bluga.net/home 和以下代码。 如果您每月只需要生成一些图像，那么它是免费的，但更多图像会收取一点费用。

（我与他们没有任何关系，我过去只是用过这个）

public enum OutputType
    {
        Png,
        Jpg
    }

    public interface IWebThumbAPI
    {
        int Delay { get; set; }
        int Width { get; set; }
        int Height { get; set; }
        OutputType OutputType { get; set; }
        WebThumbAPI Get(string url);
        WebThumbAPI Get(string url, int x, int y, int width, int height);
        System.Drawing.Image SaveSize(WebThumbSize webThumbSize);
    }

    public class WebThumbAPI : IWebThumbAPI
    {
        private readonly string apiKey;
        private IList<WebThumbResponse> webThumbResponse;
        private string jobId;
        private string ApiUrl { get; set; }
        public int Delay { get; set; }
        public int Width { get; set; }
        public int Height { get; set; }
        public OutputType OutputType { get; set; }

        public WebThumbAPI(string apiKey)
            : this(apiKey, "")
        {
        }

        public WebThumbAPI(string apiKey, string jobId)
        {
            this.apiKey = apiKey;
            OutputType = OutputType.Png;
            Width = 1024;
            Height = 768;
            Delay = 5;
            ApiUrl = "http://webthumb.bluga.net/api.php";
            this.jobId = jobId;
        }

        public WebThumbAPI Get(string url)
        {
            return Get(url, 0, 0, 400, 200);
        }

        public WebThumbAPI Get(string url, int x, int y, int width, int height)
        {
            var outputType = OutputType == OutputType.Jpg ? "jpg" : "png";

            var doc = new XDocument(
                new XElement("webthumb",
                            new XElement("apikey", apiKey),
                             new XElement("request",
                                                 new XElement("url", url),
                                                 new XElement("outputType", outputType),
                                                 new XElement("width", Width),
                                                 new XElement("height", Height),
                                                 new XElement("delay", Delay),
                                                 new XElement("excerpt",
                                                     new XElement("x", x),
                                                     new XElement("y", y),
                                                     new XElement("width", width),
                                                     new XElement("height", height)))
                    )
                );

            var request = getRequest(doc.ToString());
            var webResponse = (HttpWebResponse)request.GetResponse();
            if (webResponse.ContentType == "text/xml")
            {
                var stream = webResponse.GetResponseStream();
                var response = XDocument.Load(XmlReader.Create(stream));
                webThumbResponse = (from xml in response.Descendants("job")
                                    select new WebThumbResponse
                                    {
                                        Estimate = (int)xml.Attribute("estimate"),
                                        Time = (DateTime)xml.Attribute("time"),
                                        Url = (string)xml.Attribute("url"),
                                        Cost = (int)xml.Attribute("cost"),
                                        Job = (string)xml.Value
                                    }).ToList();
                stream.Close();
                if (webThumbResponse.Count == 0)
                    jobId = "-1";
                else
                {
                    jobId = webThumbResponse[0].Job;
                    Thread.Sleep(webThumbResponse[0].Estimate * 1000);
                }

            }
            else
            {
                throw new InvalidOperationException("Failed request");
            }
            return this;
        }

        public System.Drawing.Image SaveSize(WebThumbSize webThumbSize)
        {
            if (jobId == "-1")
                return defaultImage(webThumbSize);
            var doc = new XDocument(
                new XElement("webthumb",
                            new XElement("apikey", apiKey),
                             new XElement("fetch",
                                                 new XElement("job", jobId),
                                                 new XElement("size", Enum.GetName(typeof(WebThumbSize), webThumbSize).ToLower())
                                                 )
                    )
                );
            var request = getRequest(doc.ToString());
            var webResponse = (HttpWebResponse)request.GetResponse();
            var stream = webResponse.GetResponseStream();

            Image image = null;
            try
            {
                image = System.Drawing.Image.FromStream(stream);
            }
            catch
            {
                image = defaultImage(webThumbSize);

            }
            return image;
        }

        private Image defaultImage(WebThumbSize webThumbSize)
        {
            var s = getSize(webThumbSize);
            var b = new Bitmap(s.Width, s.Height);
            var im = Image.FromHbitmap(b.GetHbitmap());
            var gr = System.Drawing.Graphics.FromImage(im);
            gr.Clear(Color.White);
            gr.Dispose();
            return im;
        }

        private static System.Drawing.Size getSize(WebThumbSize size)
        {
            switch (size)
            {
                case WebThumbSize.Small:
                    return new Size(80, 60);
                case WebThumbSize.Excerpt:
                    return new Size(400, 200);
                default:
                    return new Size(1, 1);
            }
        }

        private HttpWebRequest getRequest(string xml)
        {
            var request = (HttpWebRequest)WebRequest.Create(ApiUrl);
            request.Method = "POST";
            request.Timeout = 20000;
            request.ContentType = "text/xml";
            request.UserAgent = @"Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en) AppleWebKit/418.8 (KHTML, like Gecko) Safari/419.3";
            request.KeepAlive = false;
            request.Pipelined = false;

            Stream newStream = request.GetRequestStream();
            var encoding = new ASCIIEncoding();
            byte[] data = encoding.GetBytes(xml);
            newStream.Write(data, 0, data.Length);
            newStream.Close();
            return request;
        }
    }

    public class WebThumbResponse
    {
        public DateTime Time;
        public string Job;
        public string Url;
        public int Cost;
        public int Estimate { get; set; }
    }

    public enum WebThumbSize
    {
        Small,
        Medium,
        Medium2,
        Large,
        Excerpt
    }

Answer 3

如果网页大量使用 JS，例如地图应用程序，那么所提供的解决方案将无法很好地工作。

发现此代码与 Webbrowser 控件一起使用更有效，但缺乏更好的...

private void waitTillLoad(WebBrowser webBrowser1)
{
   WebBrowserReadyState loadStatus;

   //wait till beginning of loading next page 
   int waittime = 100000;
   int counter = 0;
   while (true)
   {
       loadStatus = webBrowser1.ReadyState;
       Application.DoEvents();

       if ((counter > waittime) || (loadStatus == WebBrowserReadyState.Uninitialized) || (loadStatus == WebBrowserReadyState.Loading) || (loadStatus == WebBrowserReadyState.Interactive))
       {
           break;
       }
       counter++;
   }

   //wait till the page get loaded.
   counter = 0;
   while (true)
   {
       loadStatus = webBrowser1.ReadyState;
       Application.DoEvents();

       if (loadStatus == WebBrowserReadyState.Complete)
       {
           break;
       }
       counter++;

   }
}

归功于 QualityPoint Technologies，网址为 http://qualitypoint.blogspot.com/2009/03/c-webbrowser-control-synchronization.html

呵呵！

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