将网页从 ASP.NET 转换为图像

问题描述

我想在 C# 中创建一个函数，该函数获取特定网页并将其从 ASP.NET 中转换为 JPG 图像.我不想通过第三方或缩略图服务执行此操作，因为我需要完整图像.我认为我需要以某种方式利用 ASP.NET 中的 webbrowser 控件，但我只是可以'不知道从哪里开始.有人有例子吗?

I would like to create a function in C# that takes a specific webpage and coverts it to a JPG image from within ASP.NET. I don't want to do this via a third party or thumbnail service as I need the full image. I assume I would need to somehow leverage the webbrowser control from within ASP.NET but I just can't see where to get started. Does anyone have examples?

推荐答案

好吧，当我结合几个不同的解决方案时，这很容易:

Ok, this was rather easy when I combined several different solutions:

这些解决方案为我提供了一种线程安全的方式来使用来自 ASP.NET 的 WebBrowser:

These solutions gave me a thread-safe way to use the WebBrowser from ASP.NET:

http://www.beansoftware.com/ASP.NET-Tutorials/Get-Web-Site-Thumbnail-Image.aspx

http://www.eggheadcafe.com/tutorials/aspnet/b7cce396-e2b3-42d7-9571-cdc4eb38f3c1/build-a-selfcaching-asp.aspx

这个解决方案给了我一种将 BMP 转换为 JPG 的方法:

This solution gave me a way to convert BMP to JPG:

在 C# 中 Bmp 到 jpg/png

我只是修改了代码并将以下内容放入 .cs 中:

I simply adapted the code and put the following into a .cs:

using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Threading;
using System.Windows.Forms;

public class WebsiteToImage
{
    private Bitmap m_Bitmap;
    private string m_Url;
    private string m_FileName = string.Empty;

    public WebsiteToImage(string url)
    {
        // Without file
        m_Url = url;
    }

    public WebsiteToImage(string url, string fileName)
    {
        // With file
        m_Url = url;
        m_FileName = fileName;
    }

    public Bitmap Generate()
    {
        // Thread
        var m_thread = new Thread(_Generate);
        m_thread.SetApartmentState(ApartmentState.STA);
        m_thread.Start();
        m_thread.Join();
        return m_Bitmap;
    }

    private void _Generate()
    {
        var browser = new WebBrowser { ScrollBarsEnabled = false };
        browser.Navigate(m_Url);
        browser.DocumentCompleted += WebBrowser_DocumentCompleted;

        while (browser.ReadyState != WebBrowserReadyState.Complete)
        {
            Application.DoEvents();
        }

        browser.Dispose();
    }

    private void WebBrowser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
    {
        // Capture
        var browser = (WebBrowser)sender;
        browser.ClientSize = new Size(browser.Document.Body.ScrollRectangle.Width, browser.Document.Body.ScrollRectangle.Bottom);
        browser.ScrollBarsEnabled = false;
        m_Bitmap = new Bitmap(browser.Document.Body.ScrollRectangle.Width, browser.Document.Body.ScrollRectangle.Bottom);
        browser.BringToFront();
        browser.DrawToBitmap(m_Bitmap, browser.Bounds);

        // Save as file?
        if (m_FileName.Length > 0)
        {
            // Save
            m_Bitmap.SaveJPG100(m_FileName);
        }
    }
}

public static class BitmapExtensions
{
    public static void SaveJPG100(this Bitmap bmp, string filename)
    {
        var encoderParameters = new EncoderParameters(1);
        encoderParameters.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 100L);
        bmp.Save(filename, GetEncoder(ImageFormat.Jpeg), encoderParameters);
    }

    public static void SaveJPG100(this Bitmap bmp, Stream stream)
    {
        var encoderParameters = new EncoderParameters(1);
        encoderParameters.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 100L);
        bmp.Save(stream, GetEncoder(ImageFormat.Jpeg), encoderParameters);
    }

    public static ImageCodecInfo GetEncoder(ImageFormat format)
    {
        var codecs = ImageCodecInfo.GetImageDecoders();

        foreach (var codec in codecs)
        {
            if (codec.FormatID == format.Guid)
            {
                return codec;
            }
        }

        // Return
        return null;
    }
}

并且可以这样调用:

WebsiteToImage websiteToImage = new WebsiteToImage( "http://www.cnn.com", @"C:Some FolderTest.jpg");
websiteToImage.Generate();

它适用于文件和流.确保您将 System.Windows.Forms 的引用添加到您的 ASP.NET 项目中.我希望这会有所帮助.

It works with both a file and a stream. Make sure you add a reference to System.Windows.Forms to your ASP.NET project. I hope this helps.

更新:我已经更新了代码以包含捕获整个页面的能力，并且不需要任何特殊设置来只捕获其中的一部分.

这篇关于将网页从 ASP.NET 转换为图像的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！