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Thread: webcam with no user input?

  1. #1

    Thread Starter
    Lively Member manbearpig001's Avatar
    Join Date
    Oct 2009
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    73

    webcam with no user input?

    Hey guys. ive been steaming on this one for quite some time. Ive got a program that relies on remote control of the computer, and i need to be able to take a webcam image without the user having to press buttons etc. So far, ive gotten to the point where i can find my webcam, and with the help of a button, start a preview, then take the picture and save it as a jpeg.

    Problem is, when you press the button to start the preview, another dialog box shows up (not related to my code) prompting me to select a video source..

    Im confused kus it seems as though the list i find on form_load does nothing at all if when i press the button it prompts me with the same list.

    Well you can infer from this that i cannot use the btnstart_click(sender, e) on form_load because it opens a dialog that wont close until i press ok, and i already tried to sendkeys enter, it didnt work.

    anyone have any idea how i can either alter my code, or make new code to take a web cam image, and save it with no user input?

    heres my code:
    (keep in mind i did not write this, i found it from this link which i believe found it from another forum.)
    http://www.dreamincode.net/forums/showtopic106157.htm

    Code:
    Imports System.Runtime.InteropServices
    
    Public Class Form1
    
        Const WM_CAP As Short = &H400S
    
        Const WM_CAP_DRIVER_CONNECT As Integer = WM_CAP + 10
        Const WM_CAP_DRIVER_DISCONNECT As Integer = WM_CAP + 11
        Const WM_CAP_EDIT_COPY As Integer = WM_CAP + 30
    
        Const WM_CAP_SET_PREVIEW As Integer = WM_CAP + 50
        Const WM_CAP_SET_PREVIEWRATE As Integer = WM_CAP + 52
        Const WM_CAP_SET_SCALE As Integer = WM_CAP + 53
        Const WS_CHILD As Integer = &H40000000
        Const WS_VISIBLE As Integer = &H10000000
        Const SWP_NOMOVE As Short = &H2S
        Const SWP_NOSIZE As Short = 1
        Const SWP_NOZORDER As Short = &H4S
        Const HWND_BOTTOM As Short = 1
    
        Dim iDevice As Integer = 0 ' Current device ID
        Dim hHwnd As Integer ' Handle to preview window
    
        Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
            (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, _
            <MarshalAs(UnmanagedType.AsAny)> ByVal lParam As Object) As Integer
    
        Declare Function SetWindowPos Lib "user32" Alias "SetWindowPos" (ByVal hwnd As Integer, _
            ByVal hWndInsertAfter As Integer, ByVal x As Integer, ByVal y As Integer, _
            ByVal cx As Integer, ByVal cy As Integer, ByVal wFlags As Integer) As Integer
    
        Declare Function DestroyWindow Lib "user32" (ByVal hndw As Integer) As Boolean
    
        Declare Function capCreateCaptureWindowA Lib "avicap32.dll" _
            (ByVal lpszWindowName As String, ByVal dwStyle As Integer, _
            ByVal x As Integer, ByVal y As Integer, ByVal nWidth As Integer, _
            ByVal nHeight As Short, ByVal hWndParent As Integer, _
            ByVal nID As Integer) As Integer
    
        Declare Function capGetDriverDescriptionA Lib "avicap32.dll" (ByVal wDriver As Short, _
            ByVal lpszName As String, ByVal cbName As Integer, ByVal lpszVer As String, _
            ByVal cbVer As Integer) As Boolean
    
        Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
            LoadDeviceList()
            If lstDevices.Items.Count > 0 Then
                btnStart.Enabled = True
                lstDevices.SelectedIndex = 0
                btnStart.Enabled = True
            Else
                lstDevices.Items.Add("No Capture Device")
                btnStart.Enabled = False
            End If
            btnStop.Enabled = False
            btnSave.Enabled = False
            'picCapture.SizeMode = PictureBoxSizeMode.StretchImage
            picCapture.SizeMode = PictureBoxSizeMode.AutoSize
        End Sub
    
        Private Sub LoadDeviceList()
            Dim strName As String = Space(100)
            Dim strVer As String = Space(100)
            Dim bReturn As Boolean
            Dim x As Integer = 0
    
            ' 
            ' Load name of all avialable devices into the lstDevices
            '
    
            Do
                '
                '   Get Driver name and version
                '
                bReturn = capGetDriverDescriptionA(x, strName, 100, strVer, 100)
    
                '
                ' If there was a device add device name to the list
                '
                If bReturn Then lstDevices.Items.Add(strName.Trim)
                x += 1
            Loop Until bReturn = False
        End Sub
    
        Private Sub OpenPreviewWindow()
            Dim iHeight As Integer = picCapture.Height
            Dim iWidth As Integer = picCapture.Width
    
            '
            ' Open Preview window in picturebox
            '
            hHwnd = capCreateCaptureWindowA(iDevice, WS_VISIBLE Or WS_CHILD, 0, 0, 640, _
                480, picCapture.Handle.ToInt32, 0)
    
            '
            ' Connect to device
            '
            If SendMessage(hHwnd, WM_CAP_DRIVER_CONNECT, iDevice, 0) Then
                '
                'Set the preview scale
                '
                SendMessage(hHwnd, WM_CAP_SET_SCALE, True, 0)
    
                '
                'Set the preview rate in milliseconds
                '
                SendMessage(hHwnd, WM_CAP_SET_PREVIEWRATE, 66, 0)
    
                '
                'Start previewing the image from the camera
                '
                SendMessage(hHwnd, WM_CAP_SET_PREVIEW, True, 0)
    
                '
                ' Resize window to fit in picturebox
                '
                SetWindowPos(hHwnd, HWND_BOTTOM, 0, 0, 640, 480, _
                        SWP_NOMOVE Or SWP_NOZORDER)
    
                btnSave.Enabled = True
                btnStop.Enabled = True
                btnStart.Enabled = False
            Else
                '
                ' Error connecting to device close window
                ' 
                DestroyWindow(hHwnd)
    
                btnSave.Enabled = False
            End If
        End Sub
    
        Private Sub btnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStart.Click
            iDevice = lstDevices.SelectedIndex
            OpenPreviewWindow()
        End Sub
    
        Private Sub ClosePreviewWindow()
            '
            ' Disconnect from device
            '
            SendMessage(hHwnd, WM_CAP_DRIVER_DISCONNECT, iDevice, 0)
    
            '
            ' close window
            '
    
            DestroyWindow(hHwnd)
        End Sub
    
        Private Sub btnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStop.Click
            ClosePreviewWindow()
            btnSave.Enabled = False
            btnStart.Enabled = True
            btnStop.Enabled = False
        End Sub
    
        Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
            Dim data As IDataObject
            Dim bmap As Image
    
            '
            ' Copy image to clipboard
            '
            SendMessage(hHwnd, WM_CAP_EDIT_COPY, 640, 480)
    
            '
            ' Get image from clipboard and convert it to a bitmap
            '
            data = Clipboard.GetDataObject()
            If data.GetDataPresent(GetType(System.Drawing.Bitmap)) Then
                bmap = CType(data.GetData(GetType(System.Drawing.Bitmap)), Image)
                picCapture.Image = bmap
                ClosePreviewWindow()
                btnSave.Enabled = False
                btnStop.Enabled = False
                btnStart.Enabled = True
    
                bmap.Save("C:\Screenshots\pic.jpg")
    
            End If
        End Sub
    End Class

  2. #2
    Member Cyrax.NET's Avatar
    Join Date
    Feb 2007
    Posts
    54

    Re: webcam with no user input?

    i don't have the patience to look through your code right now and it maybe something simple to stop the 3rd party window coming up!

    but i would recommend you have a look at ezvidcap by Ray Mercer. Although it is quite old now and coded in VB6, I have used it in previous projects in .Net flawlessly. It also has alot of functions already coded which you may require.

    If you do use this control then you can make use of the image capture features by simply calling the method for it remotly etc.

    http://www.shrinkwrapvb.com/ezvidcap.htm

    Good Luck

  3. #3

    Thread Starter
    Lively Member manbearpig001's Avatar
    Join Date
    Oct 2009
    Posts
    73

    Re: webcam with no user input?

    hey. thanks for replying.

    i dont rly want to download source.

    maybe if there is source on the web page, il take a look at it for ideas, but i was hoping for some tips on how to ge this done without thousands of lines of unnecessary code. So far, ive been able to use my code provided, with some tweaks and timers added, to provide a 'fake' user. ive kept the buttons, and simply called them based on a timer. problem is, it works on my laptop, but when i run it on my desktop, the image is saved as a green blank page.

    This is most likely due to the fact that i ignore the third party msgbox, and simply focus on the form instead. So what i truely need from you guys, is a modified version of the code i have, so that buttons are no longer needed, or more code that works with 2008 with no buttons! :]

    thanks

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