MFC实现透明窗口

#include "stdafx.h" #include "TransparentWindow.h" #include "TransparentWindowDlg.h" #ifdef _DEBUG #define new DEBUG_NEW #endif CTransparentWindowDlg::CTransparentWindowDlg(CWnd* pParent /*=NULL*/) : CDialog(CTransparentWindowDlg::IDD, pParent) { m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME); } void CTransparentWindowDlg::DoDataExchange(CDataExchange* pDX) { CDialog::DoDataExchange(pDX); DDX_Control(pDX, IDC_SLIDER_TRANS, transSlider_); } BEGIN_MESSAGE_MAP(CTransparentWindowDlg, CDialog) ON_WM_PAINT() ON_WM_QUERYDRAGICON() //}}AFX_MSG_MAP ON_WM_HSCROLL() END_MESSAGE_MAP() // CTransparentWindowDlg message handlers BOOL CTransparentWindowDlg::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 //设置分层属性 ::SetWindowLong(GetSafeHwnd(), GWL_EXSTYLE, GetWindowLong(GetSafeHwnd(), GWL_EXSTYLE)|WS_EX_LAYERED); //设置透明度 0 - completely transparent 255 - opaque ::SetLayeredWindowAttributes(GetSafeHwnd(), 0, 200, LWA_ALPHA); transSlider_.SetRange(0, 255); transSlider_.SetPos(200); return TRUE; // return TRUE unless you set the focus to a control } void CTransparentWindowDlg::OnPaint() { if (IsIconic()) { CPaintDC dc(this); // device context for painting SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0); // Center icon in client rectangle int cxIcon = GetSystemMetrics(SM_CXICON); int cyIcon = GetSystemMetrics(SM_CYICON); CRect rect; GetClientRect(&rect); int x = (rect.Width() - cxIcon + 1) / 2; int y = (rect.Height() - cyIcon + 1) / 2; // Draw the icon dc.DrawIcon(x, y, m_hIcon); } else { DrawBkgnd(); CDialog::OnPaint(); } } // The system calls this function to obtain the cursor to display while the user drags // the minimized window. HCURSOR CTransparentWindowDlg::OnQueryDragIcon() { return static_cast<HCURSOR>(m_hIcon); } void CTransparentWindowDlg::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar) { ::SetLayeredWindowAttributes(GetSafeHwnd(), 0, transSlider_.GetPos(), LWA_ALPHA); CDialog::OnHScroll(nSBCode, nPos, pScrollBar); } void CTransparentWindowDlg::DrawBkgnd() { PAINTSTRUCT ps; HDC hdc = ::BeginPaint(GetSafeHwnd(), &ps); //HDC hdc = ::GetDC(m_hWnd); HDC hdcMem = CreateCompatibleDC(hdc); HBITMAP hBmp = (HBITMAP)LoadImage(AfxGetInstanceHandle(), _T("D:\\Sample.bmp"), IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE); BITMAP bmp; ::GetObject(hBmp, sizeof(BITMAP), &bmp); ::SetWindowPos(m_hWnd, HWND_TOPMOST, 0, 0, bmp.bmWidth, bmp.bmHeight, SWP_NOMOVE); HBITMAP hBmpOld = (HBITMAP)SelectObject(hdcMem, hBmp); BitBlt(hdc, 0, 0, bmp.bmWidth, bmp.bmHeight, hdcMem, 0, 0, SRCCOPY); SelectObject(hdcMem, hBmpOld); DeleteDC(hdcMem); ::EndPaint(GetSafeHwnd(), &ps); //::ReleaseDC(m_hWnd, hdc); }