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Capture picture from webcam to JPEG file - Code required VB.Net 2005

Posted on 2007-03-30
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Last Modified: 2013-11-26
Hi ! I am new to .Net VB (Studio 2005) and I need to insert into my form a window that would be able to capture a picture from a webcams (1 or more) and save it to a jpeg file as soon as I click on the capture button on the form.

I have searched through this database for solutions and every solution refers to some extrenal site way to complex for a beginner like me to understand or even implement.

Is some experts here available who could put some code (VB)  that could show how it's done ; even if it shows another external dll to be used. .  

I am a quick learner :-)

BASit
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Question by:BASit Bulbulia
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Expert Comment

by:doraiswamy
ID: 18822060
Check this link out. It contains all the code you need.

http://www.devx.com/dotnet/Article/30375/1763
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Author Comment

by:BASit Bulbulia
ID: 18822084
Thanks Dorais,

Nice link ; however I have managed to work through the code below:-

The problem is I need to choose more than one web cam or atleast choose just one webcam each time the code is run. With the current code the default webcam is always used.

where in the code would i be able to do so  . ..

Thanks in Advance
BASit



------------------------ CODE -------------------------------------

Imports System.Runtime.InteropServices

Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents picCapture As System.Windows.Forms.PictureBox
    Friend WithEvents lstDevices As System.Windows.Forms.ListBox
    Friend WithEvents lblDevice As System.Windows.Forms.Label
    Friend WithEvents btnStart As System.Windows.Forms.Button
    Friend WithEvents btnSave As System.Windows.Forms.Button
    Friend WithEvents btnStop As System.Windows.Forms.Button
    Friend WithEvents sfdImage As System.Windows.Forms.SaveFileDialog
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.picCapture = New System.Windows.Forms.PictureBox
        Me.lstDevices = New System.Windows.Forms.ListBox
        Me.lblDevice = New System.Windows.Forms.Label
        Me.btnStart = New System.Windows.Forms.Button
        Me.btnSave = New System.Windows.Forms.Button
        Me.btnStop = New System.Windows.Forms.Button
        Me.sfdImage = New System.Windows.Forms.SaveFileDialog
        CType(Me.picCapture, System.ComponentModel.ISupportInitialize).BeginInit()
        Me.SuspendLayout()
        '
        'picCapture
        '
        Me.picCapture.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D
        Me.picCapture.Location = New System.Drawing.Point(208, 24)
        Me.picCapture.Name = "picCapture"
        Me.picCapture.Size = New System.Drawing.Size(256, 272)
        Me.picCapture.TabIndex = 0
        Me.picCapture.TabStop = False
        '
        'lstDevices
        '
        Me.lstDevices.Location = New System.Drawing.Point(8, 55)
        Me.lstDevices.Name = "lstDevices"
        Me.lstDevices.Size = New System.Drawing.Size(184, 238)
        Me.lstDevices.TabIndex = 1
        '
        'lblDevice
        '
        Me.lblDevice.Location = New System.Drawing.Point(8, 32)
        Me.lblDevice.Name = "lblDevice"
        Me.lblDevice.Size = New System.Drawing.Size(184, 16)
        Me.lblDevice.TabIndex = 2
        Me.lblDevice.Text = "Available Devices"
        Me.lblDevice.TextAlign = System.Drawing.ContentAlignment.TopCenter
        '
        'btnStart
        '
        Me.btnStart.Location = New System.Drawing.Point(20, 320)
        Me.btnStart.Name = "btnStart"
        Me.btnStart.Size = New System.Drawing.Size(112, 32)
        Me.btnStart.TabIndex = 3
        Me.btnStart.Text = "Start Preview"
        '
        'btnSave
        '
        Me.btnSave.Anchor = CType((System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.btnSave.Location = New System.Drawing.Point(348, 320)
        Me.btnSave.Name = "btnSave"
        Me.btnSave.Size = New System.Drawing.Size(112, 32)
        Me.btnSave.TabIndex = 4
        Me.btnSave.Text = "Save Image"
        '
        'btnStop
        '
        Me.btnStop.Location = New System.Drawing.Point(184, 320)
        Me.btnStop.Name = "btnStop"
        Me.btnStop.Size = New System.Drawing.Size(112, 32)
        Me.btnStop.TabIndex = 5
        Me.btnStop.Text = "Stop Preview"
        '
        'sfdImage
        '
        Me.sfdImage.Filter = "Jpeg|*.jpg"
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(480, 382)
        Me.Controls.Add(Me.btnStop)
        Me.Controls.Add(Me.btnSave)
        Me.Controls.Add(Me.btnStart)
        Me.Controls.Add(Me.lblDevice)
        Me.Controls.Add(Me.lstDevices)
        Me.Controls.Add(Me.picCapture)
        Me.Name = "Form1"
        Me.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen
        Me.Text = "Video Capture"
        CType(Me.picCapture, System.ComponentModel.ISupportInitialize).EndInit()
        Me.ResumeLayout(False)

    End Sub

#End Region

    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
    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, picCapture.Width, picCapture.Height, _
                    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, 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
            ClosePreviewWindow()
            btnSave.Enabled = False
            btnStop.Enabled = False
            btnStart.Enabled = True


            sfdImage.InitialDirectory = "\jpegs"
            'name of file
            sfdImage.FileName = "Sample-"

            If sfdImage.ShowDialog = DialogResult.OK Then

                'save as jpeg also sfdImange filter changes
                bmap.Save(sfdImage.FileName, Imaging.ImageFormat.Jpeg)
            End If

        End If
    End Sub

    Private Sub Form1_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
        If btnStop.Enabled Then
            ClosePreviewWindow()
        End If
    End Sub
End Class

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LVL 8

Expert Comment

by:doraiswamy
ID: 18822493
OK will get back to ya soon
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LVL 8

Accepted Solution

by:
doraiswamy earned 500 total points
ID: 18828115
In the event btnStart_Click, you have the following line
iDevice = lstDevices.SelectedIndex
This determines which webcam you are going to use in case you have more than one. So it always chooses the cam you have selected.

HTH
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