An Easy Way to Create a Transparent Button

• Download source - 2.4 KB
• Download demo project - 91.2 KB

Introduction

I wanted to draw a button which is transparent to its background image and hence had gone through several articles about button styles - transparent buttons. They were all very tedious tasks of making a button transparent - erase button background, draw picture, etc. I found an easy method. The idea behind this is, draw a bitmap picture on the dialog box. Draw the same bitmap on the button from the location LeftTop of the button. Button is not visible like a button unless mouse cursor is moved on it. Therefore, I'll add two icons on the button.

//I have implemented two important functions - 
//SetTransparent() and PaintBG(CDC *pDC, CRect rc)
//SetTranparent function loads bitmap from the resource and 
//creates an handle to CDC - m_hHdc. 

void CBut::SetTransparent()
{
    HBITMAP m_hBmp = ::LoadBitmap(::AfxGetInstanceHandle(), 
        MAKEINTRESOURCE(IDB_BITMAP6));
    m_hHdc = ::CreateCompatibleDC(NULL);
    ::SelectObject(m_hHdc, m_hBmp);
} 

//PaintBG function is called in DrawItem function which draws 
//bitmap on the button from the location left-top of the button.

void CBut::PaintBG(CDC *pDC, CRect rc)
{
    CRect rect;
    GetWindowRect(rect);
    GetParent()->ScreenToClient(rect);

    if(m_hHdc!=NULL)
        ::BitBlt(pDC->m_hDC, rc.left, rc.top, rect.Width(), 
            rect.Height(), m_hHdc, rect.left, rect.top, SRCCOPY);
}

How to Use the Source Files

Draw bitmap on the dialog box in CPaint function of your CDialog derived class. Check the 'OwnerDraw' property of the button. Create a variable of type CButtonStyle in dialog class. Don't forget to include ButtonStyle.h file name in the same class.

void CButtonStyleDlg::OnPaint() 
{
    if (IsIconic())
    {
        CPaintDC dc(this); // device context for painting
        ....................
        ............
    }
    else
    {
        CPaintDC dc(this);
        CRect rect;
        GetClientRect(&rect);
        //ScreenToClient(rect);
        BITMAP bmp;
        HBITMAP hBmp = ::LoadBitmap(::AfxGetInstanceHandle(), 
            MAKEINTRESOURCE(IDB_BITMAP1));
        ::GetObject(hBmp, sizeof(bmp), &bmp);
        HDC hDC = ::CreateCompatibleDC(NULL);
        SelectObject(hDC, hBmp);

        //Note: Do not use StretchBlt function.
        ::BitBlt(dc.m_hDC, 0, 0, rect.Width(), rect.Height(), hDC, 0, 0, 
            SRCCOPY);
        CDialog::OnPaint();
    }
}

//Set button properties in OnInitDialog() function of CDialog derived class

BOOL CButtonStyleDlg::OnInitDialog()
{
    CDialog::OnInitDialog();
    .......................
    .........
    ..................

    // Set the icon for this dialog.  The framework does this automatically
    //  when the application's main window is not a dialog
    SetIcon(m_hIcon, TRUE);            // Set big icon
    SetIcon(m_hIcon, FALSE);           // Set small icon
    
    // TODO: Add extra initialization here
    m_btnButton1.SetTransparent();
    m_btnButton1.SetTextColor(RGB(0,220,0), RGB(0,255,0));
    m_btnButton1.SetIcons(IDI_ICON4, IDI_ICON4);
    m_btnButton1.FontStyle("MS Sans Serif");

    m_btnOK.SetTransparent();
    m_btnOK.SetTextColor(RGB(0,220, 0), RGB(0,255,0));
    m_btnOK.SetIcons(IDI_ICON2, IDI_ICON2);
    m_btnOK.FontStyle("MS Sans Serif");

    m_btnExit.SetTransparent();
    m_btnExit.SetTextColor(RGB(0,220,0), RGB(0,255,0));
    m_btnExit.SetIcons(IDI_ICON1, IDI_ICON1);
    m_btnExit.FontStyle("MS Sans Serif");

    m_btnClick.SetTransparent();
    m_btnClick.SetTextColor(RGB(0,220,0), RGB(0,255,0));
    m_btnClick.SetIcons(IDI_ICON3, IDI_ICON5);
    m_btnClick.FontStyle("MS Sans Serif");
    
    return TRUE;  // return TRUE unless you set the focus to a control
}

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.