Flickerproblem on some machines

From:

Tom Becker <Tom_dot_Becker_at_Ziemann_minus_Urban_dot_de>

Newsgroups:

microsoft.public.vc.mfc

Date:

Tue, 15 Jan 2008 10:36:05 +0100

Message-ID:

<uoMBOo1VIHA.5596@TK2MSFTNGP05.phx.gbl>

Hallo

I want to draw a header in an own view that slowly fades out.

My current approach is to start some timers that invalidate a rectangle
and draw the box with some gdi+ functions. See (the simplified) code below.

On some machines I get a very anoying flicker by using InvalidateRect(). The
reason is unknown.

Does anyone know a better solution to display some text that is fading out?

(Btw: I can't use drawing in a custom NC-Area as I get problems with CSplitterWnd)

thx
Tom Becker

void CMyView::OnDraw(CDC* pDC)
{
   if(m_alphaHeading > 0)
   {
     Gdiplus::Graphics graphics(pDC->m_hDC);

     DWORD capCol = GetSysColor(COLOR_ACTIVECAPTION);
     Gdiplus::SolidBrush brushBG(Gdiplus::Color(m_alphaHeading, GetRValue(capCol), GetGValue(capCol), GetBValue(capCol)));

     graphics.FillRectangle(&brushBG, m_titleRect);

     //Write some additional text
     ...
   }
}

void CMyView::OnTimer(UINT nIDEvent)
{
   if(nIDEvent == ID_TM_FADE_TITLE_START)
   {
     KillTimer(ID_TM_FADE_TITLE_START);

     m_alphaHeading = 255;
     SetTimer(ID_TM_FADE_TITLE, 50, 0);

     return;
   }

   if(nIDEvent == ID_TM_FADE_TITLE)
   {
     if(m_alphaHeading == 0)
       KillTimer(ID_TM_FADE_TITLE);
     else
     {
       m_alphaHeading--;
       InvalidateRect(titleRect, false);
     }

     return;
    }

    CFormView::OnTimer(nIDEvent);
}