Creating thumbnail of AxSHDocVw.AxWebBrowser

[Ben]

Hi all,

I am trying to write a little app that will generate a thumbnail image
of a website. Having searched the web I have found various bits of code
that appear to do the job and have written my app which works but only
sometimes! :(

The problem is - sometimes it returns a black image instead of the nice
screen shot. For example it sometimes works on the msn web site, never
works with the google web site and sometimes does not work with other
sites I try to thumbnail. The app is going to run as a console app- so
the webbrowser is not displayed on the screen. I am using the
AxSHDocVw.AxWebBrowser control to load the html page and waiting until
it has loaded the html.

Any pointers, help would be greatly appriciated

Cheers,

Ben

Here is the code I use to capture

Private Function GetHtmlBody() As IHTMLElement2

Dim wb2 As IWebBrowser2 = CType(m_IE.GetOcx(), IWebBrowser2)
Application.DoEvents()
Dim htmlDocument2 As IHTMLDocument2 = CType(wb2.Document,
IHTMLDocument2)
Application.DoEvents()
Return CType(htmlDocument2.body, IHTMLElement2)
End Function


Private Function CaptureImage() As Bitmap

Dim htmlDocument As IHTMLElement2 = GetHtmlBody()
Application.DoEvents()
Dim W As Integer = htmlDocument.scrollWidth

Dim H As Integer = htmlDocument.scrollHeight
Application.DoEvents()
If Not (m_IE.Height = H + 30) Or Not (m_IE.Width = W + 30) Then
m_IE.Height = H + 30

m_IE.Width = W + 30
End If

' Setup bitmap
Dim bitmapimg As Bitmap = New Bitmap(W, H, PixelFormat.Format24bppRgb)

Dim graphics_imgraphics As Graphics = Graphics.FromImage(bitmapimg)

Dim memdc As IntPtr = graphics_imgraphics.GetHdc()

Dim hbitmap As IntPtr = bitmapimg.GetHbitmap()

SelectObject(memdc, hbitmap)

Const PW_CLIENTONLY As Integer = &H1

Const WM_PRINT As Integer = &H317

Const PRF_NONCLIENT As Integer = &H2

Const PRF_CLIENT As Integer = &H4

Const PRF_ERASEBKGND As Integer = &H8

Const PRF_CHILDREN As Integer = &H10

Const PRF_OWNED As Integer = &H20

Const WM_PAINT As Integer = &HF

Dim rv As Integer

rv = SendMessage(m_IE.Handle, WM_PAINT, memdc, 0)

rv = SendMessage(m_IE.Handle, WM_PRINT, memdc, PRF_CHILDREN +
PRF_CLIENT + PRF_OWNED)
' Save image

Dim bitmapimg2 As Bitmap = Bitmap.FromHbitmap(hbitmap)

' Cleanup
DeleteObject(hbitmap)

graphics_imgraphics.ReleaseHdc(memdc)

graphics_imgraphics.Dispose()

bitmapimg.Dispose()
Return bitmapimg2
End Function