Re: image is not redrawed sometimes when I bring my window to foregrou
Is your MyWnd::RePaint() called from OnPaint or are you calling it from some
other place? If you are calling it from anyplace except the OnPaint message
handler then that is another big mistake. The DC that is returned from
BeginPaint is only valid in OnPaint.
The fact that you copied this code from some Microsoft sample does not make
it appropriate for MFC and does not make it appropriate outside of OnPaint
and does not make it appropriate for painting a child window from the parent
(which is never appropriate).
"Kai" <Kai@discussions.microsoft.com> wrote in message
news:60E76169-E1EF-460A-AED8-955B8093FC99@microsoft.com...
Hi All,
Thank you for your help. I posted my snippet from MyWnd::RePaint(). But
HWND hWnd;
GetDlgItem(IDC_PREVIEW_WINDOW, &hWnd);
PAINTSTRUCT ps;
HDC hdc;
RECT rcClient;
::GetClientRect(hWnd, &rcClient);
hdc = ::BeginPaint(hWnd, &ps);
if(m_pWC)
m_pWC->RepaintVideo(hWnd, hdc);
::EndPaint(hWnd, &ps);
is copied from windowless.cpp from a DirectShow sample code as follows
C:\Program Files\Microsoft
SDKs\Windows\v6.1\Samples\Multimedia\DirectShow\VMR9\Windowless
"Kai" wrote:
I use the following Repaint function to redraw my image
if (IsIconic())
{
CPaintDC dc(this); // device context for painting
SendMessage(WM_ICONERASEBKGND,
reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);
// Center icon in client rectangle
int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2;
// Draw the icon
dc.DrawIcon(x, y, m_hIcon);
}
else
{
HWND hWnd;
GetDlgItem(IDC_PREVIEW_WINDOW, &hWnd);
PAINTSTRUCT ps;
HDC hdc;
RECT rcClient;
::GetClientRect(hWnd, &rcClient);
hdc = ::BeginPaint(hWnd, &ps);
if(m_pWC)
m_pWC->RepaintVideo(hWnd, hdc);
::EndPaint(hWnd, &ps);
CDialog::OnPaint();
}
m_pWC is non zero after initialization.
for safety, I added OnActivate function
CDialog::OnActivate(nState, pWndOther, bMinimized);
// TODO: Add your message handler code here
if(nState != WA_INACTIVE)
UpdateWindow();
It doesn't seem UpdateWindow repaints window immediately.
Any better solution?
--
Scott McPhillips [VC++ MVP]