Re: Owner draw repaint

I'm drawing in response to WM_PAINT and WM_SIZE. See code below.

It works all well, as long as I do not drag another window over my app.

I just found something strange: If I drag "Windows Live Messenger" over
my app it never fails to update correctly. With another Mfc app of mine
it _can_ fail at rare occasions. With "Skype" however, the phenomenen
reveals itself more often!!??

void CTankToolDlg::OnPaint()
{
    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
    {
        CPaintDC dc( this );
        DrawCoord( &dc );
        CDialog::OnPaint();
    }
}

// The system calls this function to obtain the cursor to display while
the user drags
// the minimized window.
HCURSOR CTankToolDlg::OnQueryDragIcon()
{
    return static_cast<HCURSOR>(m_hIcon);
}

void CTankToolDlg::DrawCoord(CPaintDC *dc)
{
    COLORREF bkColor( 0xf0f0f0 );
    CBrush coordBrush( bkColor );
    CBrush *pOldBrush = dc->SelectObject( &coordBrush );
    CRect rect;
    COLORREF oldColor = dc->GetBkColor();
    dc->SetBkColor( bkColor );

    GetClientRect( &rect );

    mCoordLeft = rect.left + 60;
    mCoordRight = rect.right - 10;
    mCoordTop = rect.top + 90;
    mCoordBottom = rect.bottom - 30;
    mCoordHeight = mCoordBottom - mCoordTop;
    mCoordWidth = mCoordRight - mCoordLeft;

    dc->Rectangle( mCoordLeft, mCoordTop, mCoordRight, mCoordBottom );
    CPen pen( PS_DOT, 1, ( COLORREF ) 0 );
    CPen *pOldPen = dc->SelectObject( &pen );
    for( int n = 1; n < 10; n++ )
    {
        dc->MoveTo( mCoordLeft, mCoordBottom - ( mCoordHeight / 10 ) * n );
        dc->LineTo( mCoordRight, mCoordBottom - ( mCoordHeight / 10 ) * n );
    }

    dc->SetBkColor( oldColor );
    dc->SelectObject( pOldPen );
    dc->SelectObject( pOldBrush );
}
void CTankToolDlg::OnSize(UINT nType, int cx, int cy)
{
    CDialog::OnSize(nType, cx, cy);

    CPaintDC dc( this );
    DrawCoord( &dc );
    RedrawWindow();
}

Jonathan Wood skrev: