CaptureDIB Method

Visual Basic
C#
C++/CLI

'Declaration
 
Public Overridable Function CaptureDIB() As IntPtr

'Usage
 
Dim instance As CaptureCtrl
Dim value As IntPtr
 
value = instance.CaptureDIB()

public virtual IntPtr CaptureDIB()

public:
virtual IntPtr CaptureDIB();

Return Value

System.IntPtr

If the method succeeds, the caller must free the returned HDIB pointer by calling the Marshal.FreeHGlobal method. If the method fails, an error is raised. For more information, refer to the Error Codes.

Note: Internally this method calls StartCapture with the capture mode set to CaptureMode.Still. It then waits for the current capture delay setting specified by CaptureStillDelay before capturing the still DIB. Finally, it stops the graph by calling StopCapture.

Note: The frame data is retrieved from the underlying graph after the processing filters. If the capture needs to occur before the processing is completed use the LeadVideoCallBackFilter and place it first in the collection of processing filters.

Visual Basic
C#
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Imports Leadtools
Imports Leadtools.Multimedia
Imports LeadtoolsMultimediaExamples.Fixtures

Public _form As CaptureCtrlForm = New CaptureCtrlForm()
Public _capturectrl As CaptureCtrl = Nothing
Public _result As Boolean = False
Private _dibFile As String = Path.Combine(LEAD_VARS.MediaDir, "CaptureCtrl_CaptureDIBExample.dib")

Public Sub CaptureDIBExample()
   ' reference the capture control
   _capturectrl = _form.CaptureCtrl

   Try
      ' select a video capture device
      If _capturectrl.VideoDevices("USB") Is Nothing Then
         Throw New Exception("No USB video device available")
      End If

      _capturectrl.VideoDevices("USB").Selected = True

      ' set a video compressor for the capture file
      _capturectrl.VideoCompressors.Mpeg4.Selected = True

      ' set still delay
      _capturectrl.CaptureStillDelay = 1000

      ' capture DIB
      Dim DIB As IntPtr = _capturectrl.CaptureDIB()

      ' check for the captured DIB handle
      If (DIB <> Nothing) Then
         _result = True
      End If

      ' free allocated global memory
      Marshal.FreeHGlobal(DIB)

   Catch e1 As Exception
      _result = False
   End Try
End Sub

Public NotInheritable Class LEAD_VARS
Public Const MediaDir As String = "C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 18\Media"
End Class

using Leadtools;
using Leadtools.Multimedia;
using LeadtoolsMultimediaExamples.Fixtures;

public bool _result = false;
public CaptureCtrlForm _form = new CaptureCtrlForm();
public void CaptureDIBExample()
{
   // reference the capture control
   CaptureCtrl capturectrl = _form.CaptureCtrl;

   try
   {
       // set the video capture device. use your device's name here
      if (capturectrl.VideoDevices["Logitech"] == null)
         throw new Exception("No Logitech video device available");

      capturectrl.VideoDevices["Logitech"].Selected = true;

      // set a delay of 1 second to ensure that some capture devices
      // have time to adjust their gain
      capturectrl.CaptureStillDelay = 1000;

      // capture device independent bitmap
      IntPtr dib = capturectrl.CaptureDIB();

      _result = (dib != null);

      //free allocated global memory
      Marshal.FreeHGlobal(dib);
   }
   catch (COMException)
   {
      _result = false;
   }
   catch (Exception)
   {
      _result = false;
   }
}

Target Platforms

Reference

CaptureCtrl Class
CaptureCtrl Members