MFC SDI 利用双缓冲实现截图程序

 

废话不多说先上图

 

 

 

 

-------------------------------------------好了 开始废话

 

编译器: VC6.0

MSDN: 2008

程序功能:主要功能如图中菜单所示 且每个功能的实现代码基本一样

 仅仅将显示器能显示的部分 截取下来 然后绘制到视图中(并没有将截取的图片保存成硬盘中!)

-------------------------------------------本程序实现步骤

1. 建立MFC 单文档(SDI)程序 CGetWndBmp 注释掉工具栏 删除不需要的菜单(清晰 简单)

 

2. 在视图类 CCGetWndBmpView   OnPaint()消息中为程序添加一张背景图片

 

void CCGetWndBmpView::OnDraw(CDC* pDC){CCGetWndBmpDoc* pDoc = GetDocument();ASSERT_VALID(pDoc);// 1. 得到View的矩形区域// 2. 创建View的"客户DC"// 3. 用 "客户DC" 创建 "内存DC"// 4. 加载位图,并将该位图选入"内存DC"中// 5. 使用GetBitmap()得到加载的位图的信息// [如果使用StretchBlt()贴图][如果使用BitBlt()可忽略这一步]// 6. StretchBlt 贴图,将内存中(0,0)坐标开始的 整张位图 贴到 目标区域(整个视图区域)CRect rectView;GetClientRect(&rectView); CDC memDC;memDC.CreateCompatibleDC(pDC);CBitmap srcBmp, *pOldBmp;srcBmp.LoadBitmap(IDB_BK4VIEW);pOldBmp = memDC.SelectObject(&srcBmp);BITMAP bmpInfo;srcBmp.GetBitmap(&bmpInfo);pDC->StretchBlt(0, 0, rectView.Width(), rectView.Height(),&memDC,0, 0, bmpInfo.bmWidth, bmpInfo.bmHeight,SRCCOPY);}

 

 

由于图片覆盖了客户区的整个部分 也为了运行效率 重载函数OnEraseBkgnd()

(同样可以将OnPaint()函数中贴图的代码放到 OnEraseBkgnd() 函数中来!!)

 

 

BOOL CCGetWndBmpView::OnEraseBkgnd( CDC* pDC ){return TRUE;//return CView::OnEraseBkgnd(pDC);}

 

 

3.  添加菜单及其消息响应函数 函数名字一看便知道 [ 点击|菜单|得到|整个/半个| 屏幕/视图 ]

 

 afx_msg void OnMenuGetFullScreen();
 afx_msg void OnMenuGetFullView();
 afx_msg void OnMenuGetHalfScreen();
 afx_msg void OnMenuGetHalfView();
 afx_msg void OnMenuGetFullDesktop();

 afx_msg void OnMenuGetDialogCtrl();

 

4. 我再啰嗦一句,这几个功能的实现代码基本是一样的,有些仅仅是变动了几个参数

我没有提取出来单独作为一个函数,是想大家看的清晰一点,实现一个截取的功能 不用太复杂

 

看懂下面第一个未折叠的代码 基本就能举一反百了

 

//得到整个屏幕
A: void CMainFrame::OnMenuGetFullScreen()

 

//得到整个屏幕void CMainFrame::OnMenuGetFullScreen() {//1. 得到"桌面DC"//2. 创建"内存DC"//3. 用"桌面DC"创建"内存位图"//4. 将"内存位图"选进"内存DC"中//5. 将"桌面DC"内容拷贝到"内存DC"中//6. 创建"客户端DC"//7. 将"内存DC"内容拷贝到客户端DC中//1.CDC *pSrcDC = GetDesktopWindow()->GetWindowDC();if (pSrcDC == NULL){AfxMessageBox("获取源DC失败!");return;}//GetDeviceCaps(int nIndex) : Retrieves a wide range of device-specific information about the display device.int nWidth = pSrcDC->GetDeviceCaps(HORZRES);int nHeight = pSrcDC->GetDeviceCaps(VERTRES);if (m_memDC.m_hDC){m_memDC.DeleteDC();}m_memDC.CreateCompatibleDC(pSrcDC);CBitmap memBmp, *pOldBmp;memBmp.CreateCompatibleBitmap(pSrcDC, nWidth, nHeight);pOldBmp = m_memDC.SelectObject(&memBmp);m_memDC.BitBlt(0, 0, nWidth, nHeight, pSrcDC,0,0,SRCCOPY);//6.CClientDC dc(this);dc.BitBlt(0, 0, nWidth, nHeight, &m_memDC, 0, 0, SRCCOPY);m_memDC.SelectObject(pOldBmp);m_memDC.DeleteDC();memBmp.DeleteObject();}

 

 

 

B: 得到半个屏幕大小的图片

void CMainFrame::OnMenuGetHalfScreen()

 

// 此函数代码和上面 OnMenuGetFullScreen();的基本一样// 除了 "//***********"标注之间的代码// (注:此处若只想得到半个屏幕 可以直接取半个屏幕的图片大小 详见 OnMenuGetDialog();// 此处得到整个屏幕大小的位图,然后在整个屏幕的位图中取)void CMainFrame::OnMenuGetHalfScreen() {CDC *pSrcDC = GetDesktopWindow()->GetWindowDC();if (pSrcDC == NULL){AfxMessageBox("获取源DC失败!");return;}int nWidth = pSrcDC->GetDeviceCaps(HORZRES);int nHeight = pSrcDC->GetDeviceCaps(VERTRES);if (m_memDC.m_hDC){m_memDC.DeleteDC();}m_memDC.CreateCompatibleDC(pSrcDC);CBitmap memBmp, *pOldBmp;memBmp.CreateCompatibleBitmap(pSrcDC, nWidth, nHeight);pOldBmp = m_memDC.SelectObject(&memBmp);m_memDC.BitBlt(0, 0, nWidth, nHeight, pSrcDC,0,0,SRCCOPY);CClientDC dc(this);dc.BitBlt(0, 0, nWidth, nHeight, &m_memDC, //↓*****************************************************//0, 0, SRCCOPY);nWidth/2, nHeight/2, SRCCOPY);//↑*****************************************************m_memDC.SelectObject(pOldBmp);m_memDC.DeleteDC();memBmp.DeleteObject();}

 

 

 

C: 得到整个视图大小的图片

void CMainFrame::OnMenuGetFullView()

 

// 此函数代码和上面 OnMenuGetFullScreen();的基本一样// 除了 "//***********"标注之间的代码void CMainFrame::OnMenuGetFullView() {//↓*****************************************************//CDC *pSrcDC = GetDesktopWindow()->GetWindowDC();CDC *pSrcDC = GetWindowDC();//↑*****************************************************if (pSrcDC == NULL){AfxMessageBox("获取源DC失败!");return;}//↓*****************************************************//int nWidth = pSrcDC->GetDeviceCaps(HORZRES);//int nHeight = pSrcDC->GetDeviceCaps(VERTRES);CRect rectClient;GetClientRect(&rectClient);int nWidth = rectClient.Width();int nHeight = rectClient.Height();//↑*****************************************************if (m_memDC.m_hDC){m_memDC.DeleteDC();}m_memDC.CreateCompatibleDC(pSrcDC);CBitmap memBmp, *pOldBmp;memBmp.CreateCompatibleBitmap(pSrcDC, nWidth, nHeight);pOldBmp = m_memDC.SelectObject(&memBmp);m_memDC.BitBlt(0, 0, nWidth, nHeight, pSrcDC,0,0,SRCCOPY);CClientDC dc(this);dc.BitBlt(0, 0, nWidth, nHeight, &m_memDC, 0, 0, SRCCOPY);m_memDC.SelectObject(pOldBmp);m_memDC.DeleteDC();memBmp.DeleteObject();}

 

 

D: 得到半个试图大小的图片

void CMainFrame::OnMenuGetHalfView()

 

// 此函数代码和上面 OnMenuGetFullScreen();的基本一样// 除了 "//***********"标注之间的代码// (注:此处若只想得到半个视图 可以直接取半个视图的图片大小 详见 OnMenuGetDialog();// 此处得到整个视图大小的位图,然后在整个视图的位图中取)void CMainFrame::OnMenuGetHalfView() {//↓*****************************************************//CDC *pSrcDC = GetDesktopWindow()->GetWindowDC();CDC *pSrcDC = GetWindowDC();//↑*****************************************************if (pSrcDC == NULL){AfxMessageBox("获取源DC失败!");return;}//↓*****************************************************//int nWidth = pSrcDC->GetDeviceCaps(HORZRES);//int nHeight = pSrcDC->GetDeviceCaps(VERTRES);CRect rectClient;GetClientRect(&rectClient);int nWidth = rectClient.Width();int nHeight = rectClient.Height();//↑*****************************************************if (m_memDC.m_hDC){m_memDC.DeleteDC();}m_memDC.CreateCompatibleDC(pSrcDC);CBitmap memBmp, *pOldBmp;memBmp.CreateCompatibleBitmap(pSrcDC, nWidth, nHeight);pOldBmp = m_memDC.SelectObject(&memBmp);m_memDC.BitBlt(0, 0, nWidth, nHeight, pSrcDC,0,0,SRCCOPY);CClientDC dc(this);dc.BitBlt(0, 0, nWidth, nHeight, &m_memDC,//↓*****************************************************//0, 0, SRCCOPY);nWidth/2, nHeight/2, SRCCOPY);//↑*****************************************************m_memDC.SelectObject(pOldBmp);m_memDC.DeleteDC();memBmp.DeleteObject();}

 

 

E: 得到桌面大小的图片

void CMainFrame::OnMenuGetFullDesktop()

 

// 得到桌面位图, 原理:隐藏本程序主窗口,然后截图,然后显示出来,也就是说,并不能完全得到桌面背景(你懂得 ;)// 此函数代码和上面 OnMenuGetFullScreen();的基本一样// 除了 "//***********"标注之间的代码void CMainFrame::OnMenuGetFullDesktop() {//↓*****************************************************ShowWindow(SW_HIDE);Sleep(100);//程序运行太快 给点时间延迟//↑*****************************************************CDC *pSrcDC = GetDesktopWindow()->GetWindowDC();if (pSrcDC == NULL){AfxMessageBox("获取源DC失败!");return;}//GetDeviceCaps(int nIndex) : Retrieves a wide range of device-specific information about the display device.int nWidth = pSrcDC->GetDeviceCaps(HORZRES);int nHeight = pSrcDC->GetDeviceCaps(VERTRES);if (m_memDC.m_hDC){m_memDC.DeleteDC();}m_memDC.CreateCompatibleDC(pSrcDC);CBitmap memBmp, *pOldBmp;memBmp.CreateCompatibleBitmap(pSrcDC, nWidth, nHeight);pOldBmp = m_memDC.SelectObject(&memBmp);m_memDC.BitBlt(0, 0, nWidth, nHeight, pSrcDC,0,0,SRCCOPY);//↓*****************************************************ShowWindow(SW_SHOW);//SetRedraw() : An application calls SetRedraw to allow changes to be redrawn or to prevent changes from being redrawn.SetRedraw(FALSE); SetRedraw(TRUE);//↑*****************************************************CClientDC dc(this);dc.BitBlt(0, 0, nWidth, nHeight, &m_memDC, 0, 0, SRCCOPY);m_memDC.SelectObject(pOldBmp);m_memDC.DeleteDC();memBmp.DeleteObject();}

 

 

 

#define TIMER_ID_GET_DIALOG         (1)  定时器ID
#define TIMER_ID_GET_CTRL             (2) 定时器ID
#define DIALOG_WINDOW_POS_XY   (400)  弹出窗口位置

 

F: 

得到弹出对话框大小的图片

设置定时器截图

得到对话框中某一控件大小的图片

 

OnMenuGetDialog()

OnTimer()

OnMenuGetDialogCtrl()

 

void CMainFrame::OnMenuGetDialog() {if (!m_dlgAbout.m_hWnd){m_dlgAbout.Create(IDD_ABOUTBOX, this);}m_dlgAbout.SetWindowPos(NULL, DIALOG_WINDOW_POS_XY, DIALOG_WINDOW_POS_XY, 0, 0, SWP_NOSIZE | SWP_NOZORDER);m_dlgAbout.ShowWindow(SW_SHOW);//如果ShowWindow()后 立刻得到屏幕截图 可能由于对话框控件的初始化用掉很多时间,//导致 屏幕只得到了对话框的边框部分!SetTimer(TIMER_ID_GET_DIALOG, 1, NULL);}void CMainFrame::OnTimer()(UINT nIDEvent) {if (nIDEvent == TIMER_ID_GET_DIALOG){CDC *pSrcDC = GetDesktopWindow()->GetWindowDC();if (pSrcDC == NULL){AfxMessageBox("获取源DC失败!");return;}CRect rectDlg;m_dlgAbout.GetWindowRect(&rectDlg);int nWidth = rectDlg.Width();int nHeight = rectDlg.Height();///if (m_memDC.m_hDC){m_memDC.DeleteDC();}m_memDC.CreateCompatibleDC(pSrcDC);CBitmap memBmp, *pOldBmp;memBmp.CreateCompatibleBitmap(pSrcDC, nWidth, nHeight);pOldBmp = m_memDC.SelectObject(&memBmp);m_memDC.BitBlt(0, 0, nWidth, nHeight, pSrcDC, rectDlg.left, rectDlg.top,SRCCOPY);//6.CClientDC dc(this);dc.BitBlt(0, 0, nWidth, nHeight, &m_memDC, 0, 0, SRCCOPY);m_memDC.SelectObject(pOldBmp);m_memDC.DeleteDC();memBmp.DeleteObject();KillTimer(nIDEvent);// !!!}else if (nIDEvent == TIMER_ID_GET_CTRL){CDC *pSrcDC = GetDesktopWindow()->GetWindowDC();if (pSrcDC == NULL){AfxMessageBox("获取源DC失败!");return;}CRect rectCtrl;((CStatic* )(m_dlgAbout.GetDlgItem(IDC_STATIC_MFC)))->GetWindowRect(rectCtrl);//m_dlgAbout..GetWindowRect(&rectDlg);int nWidth = rectCtrl.Width();int nHeight = rectCtrl.Height();///if (m_memDC.m_hDC){m_memDC.DeleteDC();}m_memDC.CreateCompatibleDC(pSrcDC);CBitmap memBmp, *pOldBmp;memBmp.CreateCompatibleBitmap(pSrcDC, nWidth, nHeight);pOldBmp = m_memDC.SelectObject(&memBmp);m_memDC.BitBlt(0, 0, nWidth, nHeight, pSrcDC, rectCtrl.left, rectCtrl.top,SRCCOPY);//6.CClientDC dc(this);dc.BitBlt(0, 0, nWidth, nHeight, &m_memDC, 0, 0, SRCCOPY);m_memDC.SelectObject(pOldBmp);m_memDC.DeleteDC();memBmp.DeleteObject();KillTimer(nIDEvent);// !!!}CFrameWnd::OnTimer(nIDEvent);}void CMainFrame::OnMenuGetDialogCtrl() {if (!m_dlgAbout.m_hWnd){m_dlgAbout.Create(IDD_ABOUTBOX, this);}m_dlgAbout.SetWindowPos(NULL, DIALOG_WINDOW_POS_XY, DIALOG_WINDOW_POS_XY, 0, 0, SWP_NOSIZE | SWP_NOZORDER);m_dlgAbout.ShowWindow(SW_SHOW);//如果ShowWindow()后 立刻得到屏幕截图 可能由于对话框控件的初始化用掉很多时间,//导致 屏幕只得到了对话框的边框部分!SetTimer(TIMER_ID_GET_CTRL, 1, NULL);}

 

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程序源代码: http://download.csdn.net/source/3326623

 

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