WTL-Draw a bitmap with transparent color

class CWTLFrameView : public CWindowImpl<CWTLFrameView>

{

private:

    CBitmap m_BitmapSample;

    CBitmap m_BitmapMask;

public:

    DECLARE_WND_CLASS(NULL)

    BOOL PreTranslateMessage(MSG* pMsg)

    {

        pMsg;

        return FALSE;

    }

    BEGIN_MSG_MAP(CWTLFrameView)

        MSG_WM_CREATE(OnCreate)

        MSG_WM_PAINT(OnPaint)

    END_MSG_MAP()

    int OnCreate(LPCREATESTRUCT /*lpCreateStruct*/)

    {

        m_BitmapSample.LoadBitmap(IDB_BITMAP_SAMPLE);

        ATLASSERT(!m_BitmapSample.IsNull());

        

        CSize size;

        m_BitmapSample.GetSize(size);

        m_BitmapMask.CreateBitmap(size.cx,size.cy,1,1,NULL);

        CDC dcBmp, dcMask;

        dcBmp.CreateCompatibleDC(NULL);

        dcMask.CreateCompatibleDC(NULL);

        dcBmp.SaveDC();

        dcMask.SaveDC();

        dcBmp.SelectBitmap(m_BitmapSample);

        dcMask.SelectBitmap(m_BitmapMask);

        //Get the color of pixel on left and top corner 

        //as the tranparent color

        COLORREF clrTrans = dcBmp.GetPixel(1,1);

        dcBmp.SetBkColor(clrTrans);

        dcMask.BitBlt(0,0,size.cx,size.cy,dcBmp,0,0,SRCCOPY);

        dcBmp.SetBkColor(RGB(0,0,0));

        dcBmp.SetTextColor(RGB(255,255,255));

        dcBmp.BitBlt(0,0,size.cx,size.cy,dcMask,0,0,SRCAND);

        dcMask.RestoreDC(-1);

        dcBmp.RestoreDC(-1);

        return 0;

    }

    

    void OnPaint(CDCHandle /*dc*/)

    {

        CPaintDC dc(m_hWnd);

        //TODO: Add your drawing code here

        CDC dcBmp,dcMask;

        dcBmp.CreateCompatibleDC(dc);

        dcMask.CreateCompatibleDC(NULL);

        dcBmp.SaveDC();

        dcMask.SaveDC();

        dcBmp.SelectBitmap(m_BitmapSample);

        dcMask.SelectBitmap(m_BitmapMask);

        CSize size;

        m_BitmapSample.GetSize(size);

        dc.BitBlt(100,100,size.cx,size.cy,dcMask,0,0,SRCAND);

        dc.BitBlt(100,100,size.cx,size.cy,dcBmp,0,0,SRCPAINT);

        dcMask.RestoreDC(-1);

        dc.RestoreDC(-1);

    }

};