Hallo,
ich benutze eine WM_CAP_DRIVER Class (unten angefügt). Das Video wird gestartet und während es läuft lese ich bildweise Informationen aus.
Das klappt auch sehr gut, aber NUR wenn ich das Video gleichzeitig sehe! Weil ich wenig Platz habe, soll das Video in einer Tabpage laufen während ich in einer anderen Tabpage auf den Stream bildweise zugreifen möchte (Positionierung eines Roboters).
Das klappt nicht, erst wieder wenn ich kurz den Tabpage mit dem Video öffne, dann bekomme ich das mir zuletzt angezeigte Videobild in der anderen Tabpage.
Wie kann ich dieses Problem lösen? Bisher starte und beende ich den Stream jedes mal, wenn ich ein Standbild sehen möchte (dafür muss ich den Stream aber nicht sehen), aber als gute Lösung sehe ich das nicht an!
Gruß, Sebastian
Public Class Win32Api
#Region "Api Functions"
Private Declare Auto Function capCreateCaptureWindow 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 Integer, _
ByVal hWnd As IntPtr, _
ByVal nID As Integer) _
As IntPtr
Private Declare Auto Function SendMessage Lib "user32.dll" ( _
ByVal hwnd As IntPtr, _
ByVal uMsg As Integer, _
ByVal wParam As Integer, _
ByVal lParam As Integer) _
As Integer
#End Region
#Region "Constants"
Private Const WM_USER As Int32 = &H400
Private Const WS_CHILD As Integer = &H40000000
Private Const WS_VISIBLE As Integer = &H10000000
Private Const WM_CAP_START As Integer = WM_USER
Private Const WM_CAP_DRIVER_CONNECT As Integer = (WM_CAP_START + 10)
Private Const WM_CAP_SET_PREVIEWRATE As Integer = (WM_CAP_START + 52)
Private Const WM_CAP_SET_OVERLAY As Integer = (WM_CAP_START + 51)
Private Const WM_CAP_SET_PREVIEW As Integer = (WM_CAP_START + 50)
Private Const WM_CAP_DRIVER_DISCONNECT As Integer = (WM_CAP_START + 11)
Private Const WM_CAP_EDIT_COPY As Integer = (WM_CAP_START + 30)
#End Region
#Region "Private"
Private _hwnd As IntPtr
Private _width As Integer
Private _height As Integer
#End Region
#Region "Camera Id"
Private Const CameraId As Integer = 0
#End Region
#Region "Frames"
Private Const Frames As Integer = 10
#End Region
#Region "Positions"
Private x As Integer = 0
Private y As Integer = 0
#End Region
#Region "Public"
Public MyHandle As IntPtr
#End Region
#Region "Constructor"
Public Sub New(ByVal hWnd As IntPtr, ByVal Width As Integer, ByVal Height As Integer)
If Not hWnd.Equals(IntPtr.Zero) Then
Me._hwnd = hWnd
If (Width >= 320) And (Height >= 240) Then
Me._width = Width : Me._height = Height
Else
Return
End If
Else
Return
End If
End Sub
#End Region
#Region "Functions"
Public Function GetCaptureHandle() As IntPtr
Dim [Handle] As IntPtr = Win32Api.capCreateCaptureWindow("CaptureWindow", _
Win32Api.WS_CHILD + Win32Api.WS_VISIBLE, _
x, y, _
Me._width, Me._height, _
Me._hwnd, _
Win32Api.CameraId)
SendMessage([Handle], Win32Api.WM_CAP_DRIVER_CONNECT, Win32Api.CameraId, 0)
SendMessage([Handle], Win32Api.WM_CAP_SET_PREVIEWRATE, Win32Api.Frames, 0)
SendMessage([Handle], Win32Api.WM_CAP_SET_OVERLAY, 1, 0)
SendMessage([Handle], Win32Api.WM_CAP_SET_PREVIEW, 1, 0)
If Not [Handle].Equals(IntPtr.Zero) Then
Return [Handle]
Else
Return IntPtr.Zero
End If
End Function
Public ReadOnly Property GetImage() As Drawing.Image
Get
Return Me.SetCurrentImageToClipBoard()
End Get
End Property
Private Function SetCurrentImageToClipBoard() As Drawing.Image
Try
My.Computer.Clipboard.Clear()
SendMessage(Me.SetHandle(), Win32Api.WM_CAP_EDIT_COPY, 0, 0)
Dim img As Image = My.Computer.Clipboard.GetImage
If img IsNot Nothing Then
Return img
Else
Return Nothing
End If
Catch
Return Nothing
End Try
End Function
Public Property SetHandle() As IntPtr
Get
Return MyHandle
End Get
Set(ByVal value As IntPtr)
MyHandle = value
End Set
End Property
Public Sub DisposeConnection()
Dim result As Integer = SendMessage(Me.SetHandle(), Win32Api.WM_CAP_DRIVER_DISCONNECT, Win32Api.CameraId, 0)
Debug.WriteLine("Disconnected: " & result.ToString())
End Sub
#End Region
End Class
[VB express 2010]
