edittrans.cpp

MFC 使控件透明。很小的一个例子

/*===========================================================================
====                                                                     ====
====    File name           :  EditTrans.cpp                             ====
====    Creation date       :  7/10/2001                                 ====
====    Author(s)           :  Dany Cantin                               ====
====                                                                     ====
===========================================================================*/

#include "stdafx.h"
#include "EditTrans.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CEditTrans

CEditTrans::CEditTrans()
{
    m_TextColor = RGB(0, 0, 0);
    m_BackColor = TRANS_BACK;
}

CEditTrans::~CEditTrans()
{
}


BEGIN_MESSAGE_MAP(CEditTrans, CEdit)
	//{{AFX_MSG_MAP(CEditTrans)
	ON_WM_CTLCOLOR_REFLECT()
	ON_CONTROL_REFLECT(EN_UPDATE, OnUpdate)
	ON_WM_LBUTTONDOWN()
	ON_CONTROL_REFLECT(EN_KILLFOCUS, OnKillfocus)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CEditTrans message handlers

HBRUSH CEditTrans::CtlColor(CDC* pDC, UINT nCtlColor) 
{
    m_Brush.DeleteObject();

    if (m_BackColor == TRANS_BACK) {
        m_Brush.CreateStockObject(HOLLOW_BRUSH);
        pDC->SetBkMode(TRANSPARENT);
    }
    else {
        m_Brush.CreateSolidBrush(m_BackColor);
        pDC->SetBkColor(m_BackColor);
    }

    pDC->SetTextColor(m_TextColor);

    return (HBRUSH)m_Brush;
}


void CEditTrans::OnKillfocus() 
{
    UpdateCtrl();
}


void CEditTrans::OnUpdate() 
{
    UpdateCtrl();
}


void CEditTrans::OnLButtonDown(UINT nFlags, CPoint point) 
{
    UpdateCtrl();
    
    CEdit::OnLButtonDown(nFlags, point);
}


void CEditTrans::UpdateCtrl()
{
    CWnd* pParent = GetParent();
    CRect rect;
    
    GetWindowRect(rect);
    pParent->ScreenToClient(rect);
    rect.DeflateRect(2, 2);
    
    pParent->InvalidateRect(rect, FALSE);    
}