HOWTO: Close Application on Minimize

This is a popular question lately: how do I close my application when the user clicks the "smart minimize button"? This button does exactly that - it minimizes your application and does not close it. Your main application window is minimized when it receives a WM_SIZE message with the SIZE_MINIMIZED constant in the wParam parameter. All you have to do is call PostMessage(WM_CLOSE) and you are done. Here's a sample WTL handler:

LRESULT CCloseOnMinFrame::OnSize(UINT /*uMsg*/, 
                                 WPARAM wParam, 
                                 LPARAM /*lParam*/, 
                                 BOOL& bHandled)
{
    if(wParam == SIZE_MINIMIZED)
    {
        PostMessage(WM_CLOSE);
        bHandled = TRUE;
        return 0;
    }
    // Not handled here
    bHandled = FALSE;
    return 1;
}

HOWTO: Implement a text ticker

Here's the answer to yet another question asked on the Windows Mobile Developer Center Forums: How to implement a text ticker. The request implied for a flicker-free implementation, so a memory bitmap is required. This bitmap is generated whenever the screen changes size (CTextTickerView::OnSize) or when the text itself changes (CTextTickerView::SetTickerText). To calculate the text size when printed with the given font, a call is made to CDC::GetTextExtent which returns both the height and the width of the text in pixels. The off-screen is then created using the screen width and the text height plus a few padding pixels (CTextTickerView::ResizeBitmap).

Scrolling of the ticker is achieved through a timer that shifts the ticker printing position every 100 ms. The ticker is painted by invalidating its own rectangle and the whole painting process is performed on CTextTickerView::OnPaint. Note how the ticker text gets painted a second time tailing the first instance in order to give a continuous feel. Also note how the x offset is incremented by the timer handler. Go and have a look at the code!

Sample code: TextTicker.zip (114 KB)

HOWTO: Show the Today or Home screen

I recently answered this question on an MSDN forum: how can I show the Today screen from my application? The answer is actually quite simple:

HWND hWndDesktop = GetDesktopWindow();
SetForegroundWindow((HWND)(((ULONG) hWndDesktop) | 0x01) );

The first line of code retrieves the "desktop" window handle (the Today screen) and in the second you set it to the foreground. Easy.