Re: Copying Bitmap

If the window is obscured, then as you were already advised, you need to
call its painting procedure with your own DC.

Step-by-step how to do it:

1. Create a test MFC application project (single doc, call it "ScreenCopy").

2. Add some code to CScreenCopyView::OnDraw( CDC* pDC )

void CScreenCopyView::OnDraw(CDC* pDC )
{
    pDC->MoveTo( 20, 20 );
    pDC->LineTo( 40, 40 );
}

3. Modify the IDD_ABOUTBOX resource: add Static control and a button. Add
the member variable m_picture to map the static control, and the event
handler for the button.

4. Event handler for the button:

void CAboutDlg::OnBnClickedButtoncopy()
{
    // Get the window that displays the graphics.
    CMainFrame* pFrame = (CMainFrame*)AfxGetMainWnd();
    CScreenCopyView* pView = (CScreenCopyView*)pFrame->GetActiveView();

    // Call that window's OnDraw method to draw onto the static control
instead.
    CClientDC dcStatic( &m_picture );
    pView->OnDraw( &dcStatic );

    // If necessary, save the results as a bitmap.
    CDC dcMem;
    dcMem.CreateCompatibleDC( &dcStatic );
    CBitmap bmpCompatible;
    bmpCompatible.CreateCompatibleBitmap( &dcStatic, 100, 100 );
    dcMem.SelectObject( &bmpCompatible );
    dcMem.BitBlt( 0, 0, 100, 100, &dcStatic, 0, 0, SRCCOPY );
}

5. Compile, run. Open the "About" box and move it over the View to cover the
results of drawing. Click on the button, and you'll see that the line has
been displayed in the static control.

"Charles Tam" <CharlesTam@discussions.microsoft.com> wrote in message
news:7759C41C-10CF-4A6F-9D82-AD5D2DF1600A@microsoft.com...