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Falling Snow on Your Desktop!

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20 Dec 20062 min read 184.9K   3.8K   103   51
This article explains how to create an application that makes it snow on the desktop.

FallingSnow

Introduction

Every time the Christmas holidays come, I think about making funny toys for my desktop.

Searching through the Internet, you can easily find many wonderful desktop gifts for any occasion, including Christmas time. Unfortunately, I couldn't find any source code or open source samples of such desktop animations.

So, I decided to create my own application that makes it snow on the desktop over other windows. As I can see from the Internet, many authors use different ways to display snow fall on the desktop. I tried to create my application as simple as possible, and decided to develop a system tray application with numerous child flake windows. I think, this method is the simplest, but has a few limitations regarding memory and video usage.

General Steps

  1. Creating the main window.

    We need to create a hidden frame window and prevent more than one open ‘Snow’ window at the same time. The following code fragment shows how to do this:

    BOOL CSnowApp::InitInstance()
    {
        HWND hWnd = ::FindWindow("SnowParentWindow","Snow");
        if(hWnd) 
           return FALSE;
    
        CMainFrame* pFrame = new CMainFrame;
        m_pMainWnd = pFrame;
    
        pFrame->LoadFrame(IDR_TRAYMENU, 
                WS_OVERLAPPEDWINDOW, NULL, NULL);
    
        pFrame->ShowWindow(SW_HIDE);
    ...
    
    BOOL CMainFrame::PreCreateWindow(CREATESTRUCT& cs)
    {
    ...
        if(cs.hInstance)
        {
            static const TCHAR szClassName[] = 
                        _T("SnowParentWindow");
            WNDCLASS wc;
            GetClassInfo(cs.hInstance, cs.lpszClass, &wc);
            wc.lpszClassName = szClassName;
            AfxRegisterClass(&wc);
            cs.lpszClass = szClassName;
        }
    ...
  2. Installing the system tray icon.
    int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
    {
    ...
        SetTrayIcon(NIM_ADD, m_hIcon, "Desktop Snow");
    ...
    
    BOOL CMainFrame::SetTrayIcon(DWORD dwMessage, 
                     HICON hIcon, PSTR pszTip)
    {
        BOOL bResult = FALSE;
    
        NOTIFYICONDATA tnd;
    
        tnd.cbSize = sizeof(NOTIFYICONDATA);
        tnd.hWnd = m_hWnd;
        tnd.uID = NULL;
        tnd.uFlags = NIF_MESSAGE | NIF_ICON | NIF_TIP;
        tnd.uCallbackMessage = WM_NOTIFYTRAY;
        tnd.hIcon = hIcon; 
    
        if(pszTip) 
           lstrcpyn(tnd.szTip, pszTip, sizeof(tnd.szTip));
        else
           tnd.szTip[0] = '\0'; 
    
        bResult = Shell_NotifyIcon(dwMessage, &tnd); 
    
        return bResult;
    }
  3. Creating the array of snow flakes.

    In this application, each snow flake has been created as a non-modal dialog window with its own timer-dependent movement function.

    CRect rcWorkArea;
    SystemParametersInfo(SPI_GETWORKAREA,0,(LPVOID)&rcWorkArea,0);
    int nScreenWidth = rcWorkArea.Width();
    
    int nTimer = 5;
    int nPosX = 0;
    
    srand((unsigned)time(NULL));
    for(int i=0;i<10;i++) // 10 snow flakes
    {
        nTimer = abs(rand()*50/RAND_MAX);
        nPosX = abs(rand()*nScreenWidth/RAND_MAX);
        CFlakeDlg* fd = new CFlakeDlg(nTimer,nPosX,this);
        if(fd->Create(IDD_FLAKE,this))
        m_arSnowFlakes.Add(fd);
    }
  4. Creating a flake shape from the bitmap.

    Before running the window, we need to create a flake region that shows the window as a real snow flake. I used the 'BitmapToRegion' function from the article of Jean-Edouard Lachand-Robert, posted here.

  5. The last step: start the timer and enjoy.

    The last thing to do is start the timer and see how the flakes move. I used a very simple algorithm below, but it is sufficient to show snow movement on the desktop.

    void CFlakeDlg::OnTimer(UINT nIDEvent) 
    {
        if(nIDEvent == 1)
        {
            KillTimer(1);
    
            m_nCurrentY += 5;
            m_nCounter++;
    
            if(m_nCounter == 15)
            {
                if(((rand()*10/RAND_MAX)-5)>0) m_nIncrement = 1;
                else m_nIncrement = -1;
    
                m_nCounter = 0;
            }
    
            m_nCurrentX += m_nIncrement;
    
            if(m_nCurrentY>m_nScreenHeight)
            {
                m_nCurrentY = 0;
                m_nCurrentX = abs(rand()*m_nScreenWidth/RAND_MAX);
                m_nTimer = abs(rand()*50/RAND_MAX);
            }
    
            MoveWindow(m_nCurrentX,m_nCurrentY,17,17);
            SetTimer(1,m_nTimer,0);
        }
    
        CDialog::OnTimer(nIDEvent);
    }

This example can be extended by drawing snowdrifts on the desktop, displaying Santa, snowman, and other objects. You can experiment with the flakes positioning (top, topmost, bottom), number of flakes, falling speed etc.

Anyway, I hope others find this code useful for the Christmas holidays. Please feel free to report errors, issues, or requests.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


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Comments and Discussions

 
GeneralComment Pin
Member 1175688610-Jun-15 11:11
Member 1175688610-Jun-15 11:11 
Generalhelp me out in doing in windows Pin
mittyk12-Nov-09 23:54
mittyk12-Nov-09 23:54 
GeneralCPU %100 Pin
csf3lih20-May-07 17:42
csf3lih20-May-07 17:42 
GeneralFlicker problem with Java window Pin
x-bay2-Jan-07 7:46
x-bay2-Jan-07 7:46 
GeneralRe: Flicker problem with Java window Pin
Igor Tolmachev3-Jan-07 5:56
Igor Tolmachev3-Jan-07 5:56 
Generalfeature Pin
Nick Alexeev30-Dec-06 12:56
professionalNick Alexeev30-Dec-06 12:56 
GeneralRe: feature Pin
Igor Tolmachev3-Jan-07 6:00
Igor Tolmachev3-Jan-07 6:00 
GeneralGood Pin
A.N.Zayed28-Dec-06 5:54
A.N.Zayed28-Dec-06 5:54 
GeneralRe: Good Pin
Igor Tolmachev3-Jan-07 6:01
Igor Tolmachev3-Jan-07 6:01 
GeneralMy C# Article is here Pin
Igor Tolmachev27-Dec-06 7:39
Igor Tolmachev27-Dec-06 7:39 
GeneralFlicker problem with Active desktop Pin
dustin_26-Dec-06 5:36
dustin_26-Dec-06 5:36 
GeneralAlso Happy Eid:) Pin
Muammar©26-Dec-06 4:52
Muammar©26-Dec-06 4:52 
GeneralMerry X-Mas!! Pin
Muammar©25-Dec-06 20:53
Muammar©25-Dec-06 20:53 
GeneralVery nice snow :) Pin
Ezz Khayyat25-Dec-06 15:37
professionalEzz Khayyat25-Dec-06 15:37 
GeneralRe: Very nice snow :) Pin
Igor Tolmachev3-Jan-07 6:02
Igor Tolmachev3-Jan-07 6:02 
GeneralIts snowing on a sunny day. Pin
Prakash Nadar25-Dec-06 3:06
Prakash Nadar25-Dec-06 3:06 
GeneralVery Nice Work (and one Suggestion) Pin
Jeffrey Walton24-Dec-06 13:11
Jeffrey Walton24-Dec-06 13:11 
GeneralRe: Very Nice Work (and one Suggestion) Pin
Igor Tolmachev25-Dec-06 3:00
Igor Tolmachev25-Dec-06 3:00 
GeneralRe: Very Nice Work (and one Suggestion) Pin
Jeffrey Walton25-Dec-06 19:17
Jeffrey Walton25-Dec-06 19:17 
GeneralCool Pin
Trương Công Đa22-Dec-06 23:40
Trương Công Đa22-Dec-06 23:40 
GeneralRe: Cool Pin
Igor Tolmachev25-Dec-06 3:01
Igor Tolmachev25-Dec-06 3:01 
GeneralC# code is here [modified] Pin
Igor Tolmachev22-Dec-06 10:36
Igor Tolmachev22-Dec-06 10:36 
QuestionTerrific snowflakes! :) Pin
Raven#37722-Dec-06 8:46
Raven#37722-Dec-06 8:46 
AnswerRe: Terrific snowflakes! :) Pin
Igor Tolmachev22-Dec-06 10:33
Igor Tolmachev22-Dec-06 10:33 
QuestionGood job! Pin
sb_summer22-Dec-06 7:17
sb_summer22-Dec-06 7:17 

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