An easy way to create transparent button

Introduction

I wanted to draw a button which is transparent to its back ground 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 back ground, 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 fnction 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.

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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

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