I am trying to use getpixel to read the color of a pixel
in an external application.  I open the application using
Shell, and then get the application's window handle. From
there unfortunately, I can't seem to either a) use
showwindow or setwindowpos to bring that window to the
front, or b) even if I manually restore the window, use
getpixel to read pixel color.  This doesn't seem like too
esoteric an application and yet despite a weekend of
pouring through books and what seems like the whole MSDN
library I can't find any code that does this.  I also
can't find any code that simply reads a pixel color off
the desktop.  I'm going crazy trying to figure this out
myself and would appreciate any help.

Thank You

Hi Steve,

Depending on which OS you're using, this can be quite a tricky task (Since
too many developers misused it in the past..) however you'll find a pretty
good example of how to do this properly over on Http://www.mvps.org/vb/ ,
look for the "ForeFore.zip" demo.

To read a pixel off the desktop, use this method:

'***
Private Declare Function GetPixel Lib "gdi32" _
    (ByVal hDC As Long, ByVal x As Long, ByVal y As Long) As Long
Private Declare Function GetDesktopWindow Lib "user32" () As Long
Private Declare Function GetDC Lib "user32" (ByVal hWnd As Long) As Long
Private Declare Function ReleaseDC Lib "user32" _
    (ByVal hWnd As Long, ByVal hdc As Long) As Long

Private Function GetDeskPixel( _
    ByVal inX As Long, ByVal inY As Long) As Long
    Dim DeskWnd As Long, DeskDC As Long

    DeskWnd = GetDesktopWindow()
    DeskDC = GetDC(DeskDC)
    GetDeskPixel = GetPixel(DeskDC, inX, inY)
    Call ReleaseDC(DeskWnd, DeskDC)
End Function
'***

It seems like somewhat clunky behaviour for an application to fore a window
to the foreground to capture a pixel though, what are you trying to do with
this?
Hope this helps,

    Mike

 - Microsoft Visual Basic MVP -

WWW: Http://www.mvps.org/EDais/