how to capture image on CStatic using Logitech Web Cam

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VS2008

Visual-Studio

MFC

, +

I have a Tab Control in my Dialog.
IN myDlg.h file

C++

struct DialogItem
	{
	
		CWnd* wnd;		//our control
		int ItemID;
		int iTab;		//which tab it belongs to
		BOOL bTabStop;	//does this control allow tabstop
	};
afx_msg void CapturePhoto();
MyTab m_cTab;

In myDlg.cpp file

C++

BOOL myDlg::OnInitDialog()
{
 	CDialog::OnInitDialog();
	m_cTab.Init();
	m_cTab.InsertItem(0,"Register new user");
	m_cTab.InsertItem(1,"Identify fingerprints");
	m_cTab.InsertItem(2,"WebCam");
m_cTab.CreateImageArea("camera",4000,2,0,50,365);
m_cTab.CreateButton("WebCam",27,2,0,704,300,60);

retuen true;
	}
//On Button click
void myDlg::CapturePhoto()
{
	//hMyWindow = capCreateCaptureWindow("handle", WS_CHILD | WS_VISIBLE, 50, 150, ImageX, ImageY, this->m_hWnd,90);
	
		int id,tabID;
		tabID=m_cTab.GetCurFocus();
		INT_PTR iCount =m_cTab.obArray.GetCount();
		for(INT_PTR i=0; i<iCount; i++)
		{
		DialogItem* pItem = (DialogItem*)m_cTab.obArray[i]; 
			if(pItem->ItemID==4000&tabID==2)
			{
				id=pItem->ItemID;
				break;
			}
		}
	
		hMyWindow=::GetDlgItem(m_cTab.GetSafeHwnd(),id);
		
	bool xx = capDriverConnect( hMyWindow,0);
	if(xx == false)
	{
		AfxMessageBox("Webcam not found ",0,0);
	}
}

In MyTab.h file

C++

public:
void CreateImageArea(LPCTSTR sCaption, int nID, int iTab, UINT uLocation=0, int iX=0, int iY=0);
struct ITEM
	{
		
		CWnd* wnd;		//our control
		int nID;
		int iTab;		//which tab it belongs to
		BOOL bTabStop;	//does this control allow tabstop
	};

In MyTab.cpp file

C++

void MyTab::CreateImageArea(LPCTSTR sCaption, int nID, int iTab, UINT uLocation, int iX, int iY)
{
	ITEM* pItem = new ITEM;
	else if(iTab==2)
	{
	    PicpStatic2=new CStatic();		PicpStatic2->Create(sCaption,WS_CHILD|WS_VISIBLE|SS_BITMAP,CRect(50, 150,ImageX,ImageY),this,nID);
		PicpStatic2->SetFont(GetFont());
		PicpStatic2->ShowWindow(SW_HIDE);   
		//save the item struct to the object array
		pItem->bTabStop = FALSE;
		pItem->nID=nID;
		pItem->iTab = iTab;
		pItem->wnd = (CWnd*)(PicpStatic2);
		
	}
	else
	{
		PicpStatic->ShowWindow(SW_HIDE);
	}
	obArray.Add((CObject*)pItem);

}

On button click when I does not use capCreateCaptureWindow() method, it gives a message "Webcam not found".
When I use capCreateCaptureWindow() method and comment ::GetDlgItem(m_cTab.GetSafeHwnd(),id); it executes perfectly.
I do not want to use capCreateCaptureWindow() method. I want to use window which is dynamically created in CreateImageArea() method.

Posted 31-Oct-12 1:03am

Member 7909353

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Jochen Arndt · Answer 1 · 2012-10-31T01:22:00

Solution 1

The function capDriverConnect() expects a handle to a capture window. Such a window handles the WM_CAP_xxx messages that are send to it. Your window seems not handling these messages. capDriverConnect() is a macro that sends the WM_CAP_DRIVER_CONNECT message to the window. When this message is not handled, FALSE is returned.

Posted 31-Oct-12 1:22am

Jochen Arndt

Comments

Member 7909353 31-Oct-12 7:59am

On Button click
int id,tabID;
tabID=m_cTab.GetCurFocus();
INT_PTR iCount =m_cTab.obArray.GetCount();
for(INT_PTR i=0; i<icount; i++)
="" {
="" dialogitem*="" pitem="(DialogItem*)m_cTab.obArray[i];"
="" if(pitem-="">ItemID==4000&tabID==2)
{
id=pItem->ItemID;
break;
}
}
hMyWindow=::GetDlgItem(m_cTab.GetSafeHwnd(),id);
hMyWindow = capCreateCaptureWindow("handle", WS_CHILD | WS_VISIBLE, 50, 150, ImageX, ImageY, hMyWindow,90);
bool xx = capDriverConnect( hMyWindow,0);
if(xx == false)
{
AfxMessageBox("Webcam not found ",0,0);
}
xx is true but no image capturing occurred.

Jochen Arndt 31-Oct-12 8:14am

A cite from your question: 'it gives a message "Webcam not found".'
This message is shown by your code when capDriverConnect() returns FALSE. Otherwise, you would not see the message box.

Member 7909353 31-Oct-12 8:08am

When I does not create dynamically, I create at design time it works.

Jochen Arndt 31-Oct-12 8:35am

What do you mean by this? Using capCreateCaptureWindow()?.

The window created by capCreateCaptureWindow handles the access to the camera. You need such a window. You can't use a normal window. But you can copy data from that window to others. See this CP article for a solution using the clipboard to copy grabbed frames to another window: http://www.codeproject.com/Articles/7882/Easy-Digital-Camera-Connection

Member 7909353 31-Oct-12 8:55am

I want to use CStatic for image which is dynamically created.

Jochen Arndt 31-Oct-12 9:10am

You can't pass a handle for a 'normal' window to capDriverConnect(). You must create a capture window. Then send the WM_CAP_xxx messages to this window (or use the corresponding macros) to perform specific tasks (e.g. WM_CAP_EDIT_COPY to copy a still image to the clipboard or WM_CAP_FILE_SAVEDIB to save a still image to a bitmap file). See the link from my above comment on how to copy images to another window like your CStatic control.

Member 7909353 1-Nov-12 1:46am

hMyWindow=::GetDlgItem(m_cTab.GetSafeHwnd(),id);
hMyWindow = capCreateCaptureWindow("handle", WS_CHILD | WS_VISIBLE, 50, 150, ImageX, ImageY,hMyWindow,90);

bool xx = capDriverConnect( hMyWindow,0);
now value of hMyWindow=0x00010a62{unused=-17891602} and
capDriverConnect() return true but image does not get(show).

Jochen Arndt 1-Nov-12 4:26am

There may be two (or more) reasons:
- Your camera does not send images,
- The area of the capture window is overlayed by controls from your dialog (you are using some kind of tabbed dialog which makes is more complicated).

The MS VfW documentation is not very helpful and there are not so much examples on the web.

I suggest to use a simple program first to ensure that the camera sends images and they are shown. Then you can try to embed the code into your application.