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Image Capture Whole Web Page using C#

, 22 Jun 2005
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Capture whole web pages as a single image using C#.

Sample Image - capture.gif

Introduction

This article presents a C# routine for capturing an entire web page as an image. Many capture examples show how to grab a screen shot, but do not show how to gather information that is below the scrolling region of an application. The most common example of a scrolling problem or “run-over” program is a web page.

This application grabs the page, plus, as a bonus, it demonstrates how to let the client adjust the size of the image and the quality of the JPEG. It shows how to write the name of the webpage onto the image, draw Standard Resolution Guides, save a bitmap as a JPEG and open the directory where the captures are stored.

Background

In a recent application, I wanted to provide our Quality Assurance testers the ability to capture an entire web page. I wanted them to do this by clicking a button from within a BHO (Browser Helper Object) that is used for another testing task. I also wanted to reduce the size of the capture, because the images are e-mailed and can quickly fill up our mailbox quotas.

Using the code

The easiest way to use this code is to download the source, trim out the code functions that may not be wanted (quality of capture, size of image, URL writing, guides, or the open directory function). After the code is trimmed down and the program can compile without errors, copy the source and its dependencies into the desired project.

The first issue to face when copying the source code into a project is the need to refer SHDocVw.dll and MSHTML.dll. In Visual Studio, go to Project, Add Reference, and then select the COM tab. Now, go down to the Microsoft section and look for "Microsoft Internet Controls". Select it, and then find "Microsoft HTML Object Library" (see the above image).

After adding the references, add these necessary directives into the project. (A few other directives are needed, if the code is not loaded into a form.)

using System.Text;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.IO;
using System.Drawing.Imaging;
using SHDocVw;
using mshtml;

Import user32 functions

[DllImport("user32.dll", CharSet=CharSet.Auto)]
public static extern IntPtr FindWindowEx(IntPtr parent /*HWND*/, 
  IntPtr next /*HWND*/, string sClassName, IntPtr sWindowTitle);

[DllImport("user32.dll", ExactSpelling=true, CharSet=CharSet.Auto)] 
public static extern IntPtr GetWindow(IntPtr hWnd, int uCmd); 

[DllImport("user32.Dll")]
public static extern void GetClassName(int h, StringBuilder s, int nMaxCount);

[DllImport("user32.dll")]
private static extern bool PrintWindow(IntPtr hwnd, IntPtr hdcBlt, uint nFlags);

public const int GW_CHILD = 5; 
public const int GW_HWNDNEXT = 2;

Find an open browser and assign a browser document for it.

 SHDocVw.WebBrowser m_browser = null;
 SHDocVw.ShellWindows shellWindows = new SHDocVw.ShellWindowsClass();
 
 //Find first availble browser window.
 //Application can easily be modified to loop through and 
 //capture all open windows.
 string filename;
  foreach (SHDocVw.WebBrowser ie in shellWindows)
  {
      filename = Path.GetFileNameWithoutExtension(ie.FullName).ToLower();
      if (filename.Equals("iexplore"))
      {
          m_browser = ie;
          break;  
      }
  }
  if (m_browser == null)
  {   
      MessageBox.Show("No Browser Open");
      return;
  }

  //Assign Browser Document
  mshtml.IHTMLDocument2 myDoc = (mshtml.IHTMLDocument2)m_browser.Document;

The width and height of the web page must be determined along with the resolution settings of the clients screen.

 //Set scrolling on.
 myDoc.body.setAttribute("scroll", "yes", 0);
 
 //Get Browser Window Height
 int heightsize = (int)myDoc.body.getAttribute("scrollHeight", 0);
 int widthsize = (int)myDoc.body.getAttribute("scrollWidth", 0);
 
 //Get Screen Height
 int screenHeight = (int)myDoc.body.getAttribute("clientHeight", 0);
 int screenWidth = (int)myDoc.body.getAttribute("clientWidth", 0);

To capture the whole web page, fragments of the page will have to be grabbed and stitched together to make the whole page. After the first fragment is captured, the browser is scrolled down for the next capture. As the fragments are captured, they are stitched into a target bitmap. The process is repeated until the whole page is captured. For pages that are wider than the clients screen, the page gets scrolled over horizontally, and then the above process is repeated.

 //Get bitmap to hold screen fragment.
 Bitmap bm = new Bitmap(screenWidth, screenHeight, 
    System.Drawing.Imaging.PixelFormat.Format16bppRgb555);
 
 //Create a target bitmap to draw into.
 Bitmap bm2 = new Bitmap(widthsize + URLExtraLeft, heightsize + 
    URLExtraHeight - trimHeight, 
         System.Drawing.Imaging.PixelFormat.Format16bppRgb555);
 Graphics g2 = Graphics.FromImage(bm2);
 
 Graphics g = null;
 IntPtr hdc;
 Image screenfrag = null;
 int brwTop = 0;
 int brwLeft = 0;
 int myPage = 0;
 IntPtr myIntptr = (IntPtr)m_browser.HWND;
 
 //Get inner browser window.
 int hwndInt = myIntptr.ToInt32();
 IntPtr hwnd = myIntptr;
 hwnd = GetWindow(hwnd, GW_CHILD); 
 StringBuilder sbc = new StringBuilder(256);
 
 //Get Browser "Document" Handle
 while (hwndInt != 0) 
 { 
     hwndInt = hwnd.ToInt32();
     GetClassName(hwndInt, sbc, 256);
 
     if(sbc.ToString().IndexOf("Shell DocObject View", 0) > -1)
     {
         hwnd = FindWindowEx(hwnd, IntPtr.Zero, 
             "Internet Explorer_Server", IntPtr.Zero);
         break;
     }                
     hwnd = GetWindow(hwnd, GW_HWNDNEXT);
  } 
 
 //Get Screen Height (for bottom up screen drawing)
 while ((myPage * screenHeight) < heightsize)
 {
     myDoc.body.setAttribute("scrollTop", (screenHeight - 5) * myPage, 0);
     ++myPage;
 }
 
 //Rollback the page count by one
 --myPage;
 
 int myPageWidth = 0;
  while ((myPageWidth * screenWidth) < widthsize)
 {
     myDoc.body.setAttribute("scrollLeft", (screenWidth - 5) * myPageWidth, 0);
     brwLeft = (int)myDoc.body.getAttribute("scrollLeft", 0);
     for (int i = myPage; i >= 0; --i)
     {
         //Shoot visible window
         g = Graphics.FromImage(bm);
         hdc = g.GetHdc();
         myDoc.body.setAttribute("scrollTop", (screenHeight - 5) * i, 0);
         brwTop = (int)myDoc.body.getAttribute("scrollTop", 0);
         PrintWindow(hwnd, hdc, 0);
         g.ReleaseHdc(hdc);
         g.Flush();
         screenfrag = Image.FromHbitmap(bm.GetHbitmap());
         g2.DrawImage(screenfrag, brwLeft + URLExtraLeft, brwTop + 
            URLExtraHeight);
     }
     ++myPageWidth;
 }

Finally, save the above target to a time stamped JPEG file.

Points of Interest

I had a lot of fun and suffered a lot of frustration with this project. The captures are really nice. Try it out on one of the "Code Project" pages.

Not shown in this article, but available in the source is the saving of the file to JPEG. I tried GIF and bitmap, but settled on JPEG for size. The main goal was to be able to e-mail these files without taking up a lot of our mailbox quota.

In the actual application, I have an option to copy the file to the clipboard. I never was able to get the clipboard image into a "device dependent bitmap" state that didn't take up much size. I would copy the image, and then paste it into my Outlook e-mail, only to have the e-mail be about a MB big. When I would open the JPEG in Photoshop, then select it, copy it and paste it into Outlook, the Adobe device dependent bitmap was under 100 KB. The same happened with the simple Windows Paintbrush application.

Because of time constraints, I settled on just copying the JPEG file to Outlook. Any solutions on how to turn a large device independent bitmap into a bitmap with a small memory footprint would be welcomed.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

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About the Author

Douglas M. Weems
Web Developer
United States United States
My experience with programming began with Turbo Pascal while working on my Physics degree back in 1989.
 
After getting out of school, I used pre-VBA Excel macros to write some really fancy applications to help with the job I was doing. This inspired me to try to write "Windows" programs and to search out Visual Basic 3.0.
 
I wrote a bunch of small applications and ran them against Access and FoxPro. However, this still wasn't my primary job.
 
In 1994, I went on my first contract, a 3-month deal that turned into 3-years. I learned a lot more about development. Development was in VB3, VB4 and ASP. I got a chance to admin NT4 and SQL Server 6 and 6.5.
 
After moving on to another company, I spent another 2 years with VB and then 5 years with Java and JSP.
 
In March of 2004, I installed Visual Studio 2003. I tasted C#, and became hopelessly addicted.
 
My other interests are my 3 sons, my wife Smile | :) , metal detecting, yard work, travel and learning new things.
 
update: Now love SharePoint, PowerShell, JQuery, C#, PHP
 
location: Atlanta, Georgia
Follow on   LinkedIn

Comments and Discussions

 
QuestionNOt working in IE 8 Pinmemberravindrasinghbhati26-Mar-13 0:21 
AnswerRe: NOt working in IE 8 PinmemberDouglas M. Weems17-Oct-13 4:15 
QuestionSEE HERE HOW TO MAKE IT WORK ON LATER VERSIONS OF IE Pinmembershay_e26-Oct-12 3:53 
GeneralMy vote of 5 Pinmembermanoj kumar choubey26-Feb-12 21:28 
QuestionBad Image in Windows 7 with Visual Studio 2010 PinmemberYouzelin15-Feb-12 22:00 
AnswerRe: Bad Image in Windows 7 with Visual Studio 2010 PinmemberSabarinathan Arthanari21-Jun-12 3:03 
GeneralMy vote of 5 Pinmembernagendrasharma28-Nov-11 23:32 
QuestionNew Problem Just Started PinmemberRon Mittelman8-Nov-11 6:38 
QuestionBlack Pics Redux PinmemberRon Mittelman25-Oct-11 6:20 
AnswerRe: Black Pics Redux PinmemberRon Mittelman8-Nov-11 6:32 
Found the solution to the black screen problem after some googling.
 
Replace this:
 //Get Browser "Document" Handle
 while (hwndInt != 0) 
 { 
     hwndInt = hwnd.ToInt32();
     GetClassName(hwndInt, sbc, 256);
 
     if(sbc.ToString().IndexOf("Shell DocObject View", 0) > -1)
     {
         hwnd = FindWindowEx(hwnd, IntPtr.Zero, 
             "Internet Explorer_Server", IntPtr.Zero);
         break;
     }                
     hwnd = GetWindow(hwnd, GW_HWNDNEXT);
  } 
with this:
 //Get Browser "Document" Handle
 while (hwndInt != 0) 
 { 
     hwndInt = hwnd.ToInt32();
     GetClassName(hwndInt, sbc, 256);
 
     if (sbc.ToString().IndexOf("Shell DocObject View", 0) > -1) // pre-IE7
     {
         hwnd = FindWindowEx(hwnd, IntPtr.Zero, "Internet Explorer_Server", IntPtr.Zero);
         break;
     }
 
     if (sbc.ToString().IndexOf("TabWindowClass", 0) > -1) // IE7
     {
         hwnd = FindWindowEx(hwnd, IntPtr.Zero, "Shell DocObject View", IntPtr.Zero);
         hwnd = FindWindowEx(hwnd, IntPtr.Zero, "Internet Explorer_Server", IntPtr.Zero);
         break;
     }                
 
     if (sbc.ToString().IndexOf("Frame Tab", 0) > -1) // IE8
     {
         hwnd = FindWindowEx(hwnd, IntPtr.Zero, "TabWindowClass", IntPtr.Zero);
         hwnd = FindWindowEx(hwnd, IntPtr.Zero, "Shell DocObject View", IntPtr.Zero);
         hwnd = FindWindowEx(hwnd, IntPtr.Zero, "Internet Explorer_Server", IntPtr.Zero);
         break;
     }                
     hwnd = GetWindow(hwnd, GW_HWNDNEXT);
  } 
 
Only tested on IE 7, so may require some tweaking...
QuestionCan this be used in a ASP page or only WinForms ? PinmemberWhiskeyBusiness12-Sep-11 11:16 
GeneralBlack Pics. PinmemberI-wa-n27-Mar-11 9:43 
GeneralRe: Black Pics. PinmemberI-wa-n27-Mar-11 9:44 
GeneralRe: Black Pics. Pinmembercharles henington31-May-11 14:48 
AnswerRe: Black Pics. PinmemberRavi Sant20-Jun-11 1:38 
GeneralCode doesn't recognize scroll bars [modified] Pinmemberdsathishkumar8-Mar-11 22:36 
GeneralRe: Code doesn't recognize scroll bars Pinmemberapex7514-Mar-11 23:08 
GeneralRe: Code doesn't recognize scroll bars Pinmembercharles henington31-May-11 14:57 
GeneralMy vote of 2 Pinmembertinku5nov8-Jan-11 2:11 
RantRe: My vote of 2 Pinmembercharles henington31-May-11 15:03 
GeneralSHDocVw.ShellWindows shellWindows = new SHDocVw.ShellWindowsClass(); Pinmemberforeign26-Jan-11 0:50 
GeneralIE9 and WatiN PinmemberDaaron13-Oct-10 6:36 
GeneralTrying to use C# with IE9 and MSHTML PinmemberBobFr30-Sep-10 13:39 
QuestionBlank Image in IE9 beta Pinmemberjyotijv15-Sep-10 23:03 
GeneralMy vote of 5 PinmemberUma Sankar Achary20-Jul-10 1:08 

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