Re: Why does this TextOut() sometimes hang up?

From:

"Peter Olcott" <NoSpam@SeeScreen.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Wed, 9 May 2007 17:46:18 -0500

Message-ID:

<_as0i.54192$OT4.45666@newsfe19.lga>

"Mark Salsbery" <MarkSalsbery@discussions.microsoft.com>
wrote in message
news:03D471C4-281F-403A-A60B-A67459BF1AE9@microsoft.com...

I should have read the code more closely :)

Maybe you need to pump messages in the loop if it's on the
same thread as
the window's UI thread.

//An example message pump. Call periodically in your
loop.
MSG msg;
while ( ::PeekMessage( &msg, NULL, 0, 0, PM_NOREMOVE ) )
{
  if ( !AfxGetApp()->PumpMessage( ) )
  {
     break;
  }
}

I stuck the above code in a function called PumpMessages()
and it solved my problem, thanks!

"Peter Olcott" wrote:

"Mark Salsbery" <MarkSalsbery@discussions.microsoft.com>
wrote in message
news:E603B544-517C-4595-B222-BD6364F7792A@microsoft.com...

Are you painting over the top of your drawn text?

Besides the TextOut() in the loop you may need to
redraw
the same text in
response to WM_PAINT (OnPaint()) to make sure it's
redrawn
when the window
is repainted as well as in the loop.

Mark

I am using the basic double buffering method that paints
a
memory DC to the screen.

"Peter Olcott" wrote:

I tried to make the equivalent of a simple ProgressBar
by
displaying a count in the window of the outermost one
of
several nested loops. This process is very CPU
intensive
so
I have to force screen updates. The count works
correctly
unless I move the window, and then the window is no
longer
updated. What is causing this, and how can I fix it?

// The TextOut() display code inside a very tight loop
    ClientArea.TextOut(0, 0, String, strlen(String));
    MainWin->InvalidateRect(NULL);
    MainWin->UpdateWindow();

// Window member data
  CDC ClientArea; // virtual window device
context
  CBitmap m_bmp; // virtual window bitmap

// Window Constructor
MainWindow::MainWindow()
{
  ScreenWidth = GetSystemMetrics(SM_CXSCREEN);
  ScreenHeight = GetSystemMetrics(SM_CYSCREEN);
  Create(NULL, "SeeScreen the Screen Recognizer",
WS_OVERLAPPEDWINDOW | WS_HSCROLL | WS_VSCROLL,
rectDefault,
NULL, "TextMenu");
  CClientDC DC(this);

  // Create bitmap for virtual window
  ClientArea.CreateCompatibleDC(&DC);
  m_bmp.CreateCompatibleBitmap(&DC, ScreenWidth,
ScreenHeight);
  ClientArea.SelectObject(&m_bmp);

  // use standard background
  MainBrush.CreateStockObject(WHITE_BRUSH);
  ClientArea.SelectObject(&MainBrush);

  // paint background of virtual window
  ClientArea.PatBlt(0, 0, ScreenWidth, ScreenHeight,
PATCOPY);
}

// Update screen using contents of virtual window.
afx_msg void MainWindow::OnPaint()
{
  CPaintDC DC(this);
  DC.BitBlt(0, 0, ScreenWidth, ScreenHeight,
&ClientArea,
0,
0, SRCCOPY);
}