Webcam Viewer Edu

A windows software app that captures webcam images using the Microsoft avicap32.dll. Developed using Microsoft Visual Studio 2008 in Visual Basic.Net. Source code along with the release are for educational purposes only. Download the source code in this link and the release bin here.

Source Code Bits

This are the windows calls used to interact with avicap32.dll api, you may copy this source:

    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

    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

Procedure used to load the device:

Private Sub LoadDevice()

Dim strCamName As String = Space(100)

Dim strCamVersion As String = Space(100)

Dim bReturn As Boolean = True

Dim iCount As Integer = 0

' Load name of all avialable devices into the lstDevices

Do

' Get Driver name and version

bReturn = capGetDriverDescriptionA(iCount, strCamName, 100, strCamVersion, 100)

' If there was a device add device name to the list

If bReturn Then

iDevice = 0

lblstatus.Text = strCamName & " " & strCamVersion

End If

iCount += 1

Loop Until bReturn = False

If iCount = 0 Then

MsgBox("There is no capture device installed.", MsgBoxStyle.Information + MsgBoxStyle.OkOnly, Application.ProductName)

Me.Close()

End If

End Sub

Procedure to start the capturing of image from webcam to the picturebox control:

Private Sub StartCapture()

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, 320, _

240, 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, picCapture.Width, picCapture.Height, _

SWP_NOMOVE Or SWP_NOZORDER)

StartCaptireToolStripMenuItem.Enabled = False

EndCaptureToolStripMenuItem.Enabled = True

SaveImageToolStripMenuItem.Enabled = True

Else

' Error connecting to device close window

DestroyWindow(hHwnd)

StartCaptireToolStripMenuItem.Enabled = True

EndCaptureToolStripMenuItem.Enabled = True

SaveImageToolStripMenuItem.Enabled = True

End If

End Sub

End capture procedure:

Private Sub EndCapture()

' Disconnect from device

SendMessage(hHwnd, WM_CAP_DRIVER_DISCONNECT, iDevice, 0)

' close window

DestroyWindow(hHwnd)

StartCaptireToolStripMenuItem.Enabled = True

EndCaptureToolStripMenuItem.Enabled = True

SaveImageToolStripMenuItem.Enabled = False

End Sub

Save image procedure:

Private Sub SaveImage()

Dim data As IDataObject

Dim bmap As Image

' Copy image to clipboard

SendMessage(hHwnd, WM_CAP_EDIT_COPY, 0, 0)

' 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

StartCapture()

StartCaptireToolStripMenuItem.Enabled = True

EndCaptureToolStripMenuItem.Enabled = True

SaveImageToolStripMenuItem.Enabled = False

sfdImage.Title = "Save Bitmap Image"

sfdImage.Filter = "Bitmap Image (*.bmp)|*.bmp"

sfdImage.AddExtension = True

sfdImage.AutoUpgradeEnabled = True

sfdImage.DefaultExt = ".bmp"

sfdImage.OverwritePrompt = True

sfdImage.SupportMultiDottedExtensions = True

If sfdImage.ShowDialog = DialogResult.OK Then

bmap.Save(sfdImage.FileName, Imaging.ImageFormat.Bmp)

End If

End If

End Sub

Webcam Viewer Edu is developed and maintained by Bangon Kali only for educational purpose. No copyright infringement intended.

We can email you the source code for this program.