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| 关键词： CCaptureDlg data AFX MESSAGE UCHAR virtual CAboutDlg 热键 BOOL void |
在Windows操作系统中，当用户按下"PrintScreen"按钮后，Windows自动将当前屏幕的图像拷贝到系统剪贴板中，这时可以通过"画笔"这个小程序将剪贴板中的内容保存成图像文件，可以看出，如果需要将当前屏幕保存下来还是比较麻烦的，能否可以自己编写一个应用程序，自动将当前屏幕的内容保存到一个图像文件中去呢？这个答案是肯定的，本实例应用程序就是利用通用的热键管理DLL库实现的热键功能，在收到热键通知后截取屏幕的内容并保存到bmp文件中。例如我们设置图片保存路径为c：\，热键为F9 + Control，然后按Change按钮设置好热键，那么当我们按下CTRL+F9后，当前界面将以BMP图像文件的格式被保存在C：\目录下。程序编译运行后的界面效果如图一所示： 图一、屏幕抓图程序界面效果图 一、实现方法 热键管理DLL实际上是一个键盘钩子，由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便，本实例把它做成了一个标准的管理库来为其它的程序通过热键服务，它有两个输出函数：AddHotkey（）和DeleteHotkey（），程序只需要调用这两个函数就可以了，如果编译之后不用改变热键，则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中，定义如下： #pragma data_seg("shareddata")HHOOK hHook =NULL; //钩子句柄UINT nHookCount =0; //挂接的程序数目static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkeystatic int KeyCount =0;static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1#pragma data_seg() 关于共享段，有几点重要的说明：一是必须在链接选项里指定该段为共享：一种方法是在project->settings->link->object/library中加上/section:shareddata,rws；第二种方法是在def文件的sections里加上一句shareddata read write shared；第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化，否则链接程序会把它放到普通数据段。三是如果不初始化变量，需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。 DLL中的两个输出函数分别用来添加/删除热键，函数代码如下： BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask) { BOOL bAdded=FALSE; for(int index=0;index<MAX_KEY;index++){ if(hCallWnd[index]==0){ hCallWnd[index]=hWnd; HotKey[index]=cKey; HotKeyMask[index]=cMask; bAdded=TRUE; KeyCount++; break; } } return bAdded;}//删除热键BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask) { BOOL bRemoved=FALSE; for(int index=0;index<MAX_KEY;index++){ if(hCallWnd[index]==hWnd){ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){ hCallWnd[index]=NULL; HotKey[index]=0; HotKeyMask[index]=0; bRemoved=TRUE; KeyCount--; break; } } } return bRemoved;} DLL中的钩子函数如下： LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam){ BOOL bProcessed=FALSE; if(HC_ACTION==nCode) { if((lParam&0xc0000000)==0xc0000000){// 有键松开 switch(wParam) { case VK_MENU: MaskBits&=~ALTBIT; break; case VK_CONTROL: MaskBits&=~CTRLBIT; break; case VK_SHIFT: MaskBits&=~SHIFTBIT; break; default: //judge the key and send message break; } for(int index=0;index<MAX_KEY;index++){ if(hCallWnd[index]==NULL) continue; if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits)) { SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP); bProcessed=TRUE; } } } else if((lParam&0xc000ffff)==1){ //有键按下 switch(wParam) { case VK_MENU: MaskBits|=ALTBIT; break; case VK_CONTROL: MaskBits|=CTRLBIT; break; case VK_SHIFT: MaskBits|=SHIFTBIT; break; default: //judge the key and send message break; } for(int index=0;index<MAX_KEY;index++){ if(hCallWnd[index]==NULL) continue; if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits)) { SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN); bProcessed=TRUE; } } } if(!bProcessed){ //一般按键事件，为监视键盘的程序留出余地 for(int index=0;index<MAX_KEY;index++){ if(hCallWnd[index]==NULL) continue; if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0)) SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam); //lParam的意义可看MSDN中WM_KEYDOWN部分 } } } return CallNextHookEx( hHook, nCode, wParam, lParam ); } 抓图程序是一个基于对话框的程序，它在建立对话框的时候调用前面的DLL，登记热键，因此需要将hook.lib添加到工程里，在程序里给出两个DLL函数的定义，也可以写个头文件，再包含进来以下代码： BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask); 为了添加应用程序对热键通知事件的响应，程序中用的办法是重载WindowProc（）函数，该函数代码如下： LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam) { if(message==WM_HOTKEY&&lParam==WM_KEYDOWN) { //lParam表示是按下还是松开，如果有多个热键，由wParam来区分 SaveBmp(); return FALSE; } …… //其它处理及默认处理} 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp（）来完成的，具体实现参见代码部分。另外为了顺利实现屏幕抓图，程序中还实现了"托盘"功能，由于这一部分本书在实例中已经专门介绍过了，所以不再赘述，读者朋友可以参考相关实例。 最后需要提醒读者朋友们注意的是，源程序的编译与使用时要先编译hook.dll并将其放在系统目录（win2000/NT是system32，98/ME是system），然后编译对话框程序运行即可。 二、编程步骤 1、 启动Visual C++，生成一个DLL项目和一个基于对话框的应用程序项目，并将两个项目分别命名为"Hook"和"Capture"； 2、 在"Hook"项目中导出AddHotkey（）、DeleteHotkey（）函数； 3、 在"Capture"项目中按照图一所示设置对话框的界面，具体设置参见代码部分； 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数，并重载对话框的WindowProc（）函数； 5、 添加代码，编译运行程序。 三、程序代码 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL#if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)#define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_#if _MSC_VER > 1000#pragma once#endif // _MSC_VER > 1000#ifndef __AFXWIN_H__#error include 'stdafx.h' before including this file for PCH#endif#include "resource.h" // main symbols class CHookApp : public CWinApp{ public: CHookApp(); // Overrides // ClassWizard generated virtual function overrides //{{AFX_VIRTUAL(CHookApp) public: virtual BOOL InitInstance(); virtual int ExitInstance(); //}}AFX_VIRTUAL //{{AFX_MSG(CHookApp) // NOTE - the ClassWizard will add and remove member functions here. // DO NOT EDIT what you see in these blocks of generated code ! //}}AFX_MSG DECLARE_MESSAGE_MAP()};LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);BOOL InitHotkey();BOOL UnInit();#endif //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.#include "stdafx.h"#include "hook.h"#include <windowsx.h>#ifdef _DEBUG#define new DEBUG_NEW#undef THIS_FILEstatic char THIS_FILE[] = __FILE__;#endif#define MAX_KEY 100#define CTRLBIT 0x04#define ALTBIT 0x02#define SHIFTBIT 0x01 #pragma data_seg("shareddata")HHOOK hHook =NULL;UINT nHookCount =0;static UCHAR HotKey[MAX_KEY] = {0}; //hotkeystatic UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFTstatic HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkeystatic int KeyCount =0;static UCHAR MaskBits =0; //00000 Ctrl Alt Shift#pragma data_seg()HINSTANCE hins;void VerifyWindow();BEGIN_MESSAGE_MAP(CHookApp, CWinApp)//{{AFX_MSG_MAP(CHookApp)// NOTE - the ClassWizard will add and remove mapping macros here.// DO NOT EDIT what you see in these blocks of generated code!//}}AFX_MSG_MAPEND_MESSAGE_MAP()CHookApp::CHookApp(){ // TODO: add construction code here, // Place all significant initialization in InitInstance}CHookApp theApp;LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam){ BOOL bProcessed=FALSE; if(HC_ACTION==nCode) { if((lParam&0xc0000000)==0xc0000000){// Key up switch(wParam) { case VK_MENU: MaskBits&=~ALTBIT; break; case VK_CONTROL: MaskBits&=~CTRLBIT; break; case VK_SHIFT: MaskBits&=~SHIFTBIT; break; default: //judge the key and send message break; } for(int index=0;index<MAX_KEY;index++){ if(hCallWnd[index]==NULL) continue; if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits)) { SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP); bProcessed=TRUE; } } } else if((lParam&0xc000ffff)==1){ //Key down switch(wParam) { case VK_MENU: MaskBits|=ALTBIT; break; case VK_CONTROL: MaskBits|=CTRLBIT; break; case VK_SHIFT: MaskBits|=SHIFTBIT; break; default: //judge the key and send message break; } for(int index=0;index<MAX_KEY;index++) { if(hCallWnd[index]==NULL) continue; if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits)) { SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN); bProcessed=TRUE; } } } if(!bProcessed){ for(int index=0;index<MAX_KEY;index++){ if(hCallWnd[index]==NULL) continue; if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0)) SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam); } } } return CallNextHookEx( hHook, nCode, wParam, lParam ); }BOOL InitHotkey(){ if(hHook!=NULL){ nHookCount++; return TRUE; } else hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0); if(hHook!=NULL) nHookCount++; return (hHook!=NULL);}BOOL UnInit(){ if(nHookCount>1){ nHookCount--; return TRUE; } BOOL unhooked = UnhookWindowsHookEx(hHook); if(unhooked==TRUE){ nHookCount=0; hHook=NULL; } return unhooked;} BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask){ BOOL bAdded=FALSE; for(int index=0;index<MAX_KEY;index++){ if(hCallWnd[index]==0){ hCallWnd[index]=hWnd; HotKey[index]=cKey; HotKeyMask[index]=cMask; bAdded=TRUE; KeyCount++; break; } } return bAdded;}BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask){ BOOL bRemoved=FALSE; for(int index=0;index<MAX_KEY;index++){ if(hCallWnd[index]==hWnd){ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){ hCallWnd[index]=NULL; HotKey[index]=0; HotKeyMask[index]=0; bRemoved=TRUE; KeyCount--; break; } } } return bRemoved;}void VerifyWindow(){ for(int i=0;i<MAX_KEY;i++){ if(hCallWnd[i]!=NULL){ if(!IsWindow(hCallWnd[i])){ hCallWnd[i]=NULL; HotKey[i]=0; HotKeyMask[i]=0; KeyCount--; } } }}BOOL CHookApp::InitInstance() { AFX_MANAGE_STATE(AfxGetStaticModuleState()); hins=AfxGetInstanceHandle(); InitHotkey(); return CWinApp::InitInstance();}int CHookApp::ExitInstance() { VerifyWindow(); UnInit(); return CWinApp::ExitInstance();}////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_)#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_#if _MSC_VER > 1000#pragma once#endif // _MSC_VER > 1000class CCaptureDlg : public CDialog{ // Construction public: BOOL bTray; BOOL bRegistered; BOOL RegisterHotkey(); UCHAR cKey; UCHAR cMask; void DeleteIcon(); void AddIcon(); UINT nCount; void SaveBmp(); CCaptureDlg(CWnd* pParent = NULL); // standard constructor // Dialog Data //{{AFX_DATA(CCaptureDlg) enum { IDD = IDD_CAPTURE_DIALOG }; CComboBox m_Key; BOOL m_bControl; BOOL m_bAlt; BOOL m_bShift; CString m_Path; CString m_Number; //}}AFX_DATA // ClassWizard generated virtual function overrides //{{AFX_VIRTUAL(CCaptureDlg) public: virtual BOOL PreTranslateMessage(MSG* pMsg); protected: virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); //}}AFX_VIRTUAL // Implementation protected: HICON m_hIcon; // Generated message map functions //{{AFX_MSG(CCaptureDlg) virtual BOOL OnInitDialog(); afx_msg void OnSysCommand(UINT nID, LPARAM lParam); afx_msg void OnPaint(); afx_msg HCURSOR OnQueryDragIcon(); virtual void OnCancel(); afx_msg void OnAbout(); afx_msg void OnBrowse(); afx_msg void OnChange(); //}}AFX_MSG DECLARE_MESSAGE_MAP()};#endif ////////////////////////////////////////////////////////////// CaptureDlg.cpp : implementation file#include "stdafx.h"#include "Capture.h"#include "CaptureDlg.h"#include <windowsx.h>#pragma comment(lib,"hook.lib")#ifdef _DEBUG#define new DEBUG_NEW#undef THIS_FILEstatic char THIS_FILE[] = __FILE__;#endif#define IDM_SHELL WM_USER+1BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);UCHAR Key_Table[]={0x78,0x79,0x7a,0x7b,0x6a,0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39};class CAboutDlg : public CDialog{ public: CAboutDlg(); // Dialog Data //{{AFX_DATA(CAboutDlg) enum { IDD = IDD_ABOUTBOX }; //}}AFX_DATA // ClassWizard generated virtual function overrides //{{AFX_VIRTUAL(CAboutDlg) protected: virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support //}}AFX_VIRTUAL // Implementation protected: //{{AFX_MSG(CAboutDlg) //}}AFX_MSG DECLARE_MESSAGE_MAP()};CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD){ //{{AFX_DATA_INIT(CAboutDlg) //}}AFX_DATA_INIT}void CAboutDlg::DoDataExchange(CDataExchange* pDX){ CDialog::DoDataExchange(pDX); //{{AFX_DATA_MAP(CAboutDlg) //}}AFX_DATA_MAP}BEGIN_MESSAGE_MAP(CAboutDlg, CDialog) //{{AFX_MSG_MAP(CAboutDlg) // No message handlers //}}AFX_MSG_MAPEND_MESSAGE_MAP()CCaptureDlg::CCaptureDlg(CWnd* pParent /*=NULL*/): CDialog(CCaptureDlg::IDD, pParent){ //{{AFX_DATA_INIT(CCaptureDlg) m_bControl = FALSE; m_bAlt = FALSE; m_bShift = FALSE; m_Path = _T("c:\\"); m_Number = _T("0 picture captured."); nCount=0; bRegistered=FALSE; bTray=FALSE; //}}AFX_DATA_INIT // Note that LoadIcon does not require a subsequent DestroyIcon in Win32 m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);}void CCaptureDlg::DoDataExchange(CDataExchange* pDX){ CDialog::DoDataExchange(pDX); //{{AFX_DATA_MAP(CCaptureDlg) DDX_Control(pDX, IDC_KEY, m_Key); DDX_Check(pDX, IDC_CONTROL, m_bControl); DDX_Check(pDX, IDC_ALT, m_bAlt); DDX_Check(pDX, IDC_SHIFT, m_bShift); DDX_Text(pDX, IDC_PATH, m_Path); DDX_Text(pDX, IDC_NUMBER, m_Number); //}}AFX_DATA_MAP}BEGIN_MESSAGE_MAP(CCaptureDlg, CDialog)//{{AFX_MSG_MAP(CCaptureDlg) ON_WM_SYSCOMMAND() ON_WM_PAINT() ON_WM_QUERYDRAGICON() ON_BN_CLICKED(ID_ABOUT, OnAbout) ON_BN_CLICKED(IDC_BROWSE, OnBrowse) ON_BN_CLICKED(ID_CHANGE, OnChange)//}}AFX_MSG_MAPEND_MESSAGE_MAP()BOOL CCaptureDlg::OnInitDialog(){ CDialog::OnInitDialog(); ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX); ASSERT(IDM_ABOUTBOX < 0xF000); CMenu* pSysMenu = GetSystemMenu(FALSE); if (pSysMenu != NULL) { CString strAboutMenu; strAboutMenu.LoadString(IDS_ABOUTBOX); if (!strAboutMenu.IsEmpty()) { pSysMenu->AppendMenu(MF_SEPARATOR); pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu); } } SetIcon(m_hIcon, TRUE); // Set big icon SetIcon(m_hIcon, FALSE); // Set small icon m_Key.SetCurSel(0); RegisterHotkey(); CMenu* pMenu=GetSystemMenu(FALSE); pMenu->DeleteMenu(SC_MAXIMIZE,MF_BYCOMMAND); pMenu->DeleteMenu(SC_SIZE,MF_BYCOMMAND); pMenu->DeleteMenu(SC_RESTORE,MF_BYCOMMAND); return TRUE; // return TRUE unless you set the focus to a control}void CCaptureDlg::OnSysCommand(UINT nID, LPARAM lParam){ if ((nID & 0xFFF0) == IDM_ABOUTBOX) { CAboutDlg dlgAbout; dlgAbout.DoModal(); } else { CDialog::OnSysCommand(nID, lParam); }}void CCaptureDlg::OnPaint() { if (IsIconic()) { CPaintDC dc(this); // device context for painting SendMessage(WM_ICONERASEBKGND, (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 { CDialog::OnPaint(); }}HCURSOR CCaptureDlg::OnQueryDragIcon(){ return (HCURSOR) m_hIcon;}void CCaptureDlg::OnCancel() { if(bTray) DeleteIcon(); CDialog::OnCancel();}void CCaptureDlg::OnAbout() { CAboutDlg dlg; dlg.DoModal();}void CCaptureDlg::OnBrowse() { CString str; BROWSEINFO bi; char name[MAX_PATH]; ZeroMemory(&bi,sizeof(BROWSEINFO)); bi.hwndOwner=GetSafeHwnd(); bi.pszDisplayName=name; bi.lpszTitle="Select folder"; bi.ulFlags=BIF_RETURNONLYFSDIRS; LPITEMIDLIST idl=SHBrowseForFolder(&bi); if(idl==NULL) return; SHGetPathFromIDList(idl,str.GetBuffer(MAX_PATH)); str.ReleaseBuffer(); m_Path=str; if(str.GetAt(str.GetLength()-1)!='\\') m_Path+="\\"; UpdateData(FALSE);}void CCaptureDlg::SaveBmp(){ CDC dc; dc.CreateDC("DISPLAY",NULL,NULL,NULL); CBitmap bm; int Width=GetSystemMetrics(SM_CXSCREEN); int Height=GetSystemMetrics(SM_CYSCREEN); bm.CreateCompatibleBitmap(&dc,Width,Height); CDC tdc; tdc.CreateCompatibleDC(&dc); CBitmap*pOld=tdc.SelectObject(&bm); tdc.BitBlt(0,0,Width,Height,&dc,0,0,SRCCOPY); tdc.SelectObject(pOld); BITMAP btm; bm.GetBitmap(&btm); DWORD size=btm.bmWidthBytes*btm.bmHeight; LPSTR lpData=(LPSTR)GlobalAllocPtr(GPTR,size); BITMAPINFOHEADER bih; bih.biBitCount=btm.bmBitsPixel; bih.biClrImportant=0; bih.biClrUsed=0; bih.biCompression=0; bih.biHeight=btm.bmHeight; bih.biPlanes=1; bih.biSize=sizeof(BITMAPINFOHEADER); bih.biSizeImage=size; bih.biWidth=btm.bmWidth; bih.biXPelsPerMeter=0; bih.biYPelsPerMeter=0; GetDIBits(dc,bm,0,bih.biHeight,lpData,(BITMAPINFO*)&bih,DIB_RGB_COLORS); static int filecount=0; CString name; name.Format("pict%04d.webp",filecount++); name=m_Path+name; BITMAPFILEHEADER bfh; bfh.bfReserved1=bfh.bfReserved2=0; bfh.bfType=((WORD)('M'<< 8)|'B'); bfh.bfSize=54+size; bfh.bfOffBits=54; CFile bf; if(bf.Open(name,CFile::modeCreate|CFile::modeWrite)){ bf.WriteHuge(&bfh,sizeof(BITMAPFILEHEADER)); bf.WriteHuge(&bih,sizeof(BITMAPINFOHEADER)); bf.WriteHuge(lpData,size); bf.Close(); nCount++; } GlobalFreePtr(lpData); if(nCount==1) m_Number.Format("%d picture captured.",nCount); else m_Number.Format("%d pictures captured.",nCount); UpdateData(FALSE);}BOOL CCaptureDlg::PreTranslateMessage(MSG* pMsg) { if(pMsg -> message == WM_KEYDOWN) { if(pMsg -> wParam == VK_ESCAPE) return TRUE; if(pMsg -> wParam == VK_RETURN) return TRUE; } return CDialog::PreTranslateMessage(pMsg);}LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam) { if(message==WM_HOTKEY&&lParam==WM_KEYDOWN){ SaveBmp(); return FALSE;}if(message==IDM_SHELL&&lParam==WM_RBUTTONUP){ CMenu pop; pop.LoadMenu(MAKEINTRESOURCE(IDR_MENU1)); CMenu*pMenu=pop.GetSubMenu(0); pMenu->SetDefaultItem(ID_EXITICON); CPoint pt; GetCursorPos(&pt); int id=pMenu->TrackPopupMenu(TPM_RIGHTALIGN|TPM_NONOTIFY|TPM_RETURNCMD|TPM_LEFTBUTTON,pt.x,pt.y,this); if(id==ID_EXITICON) DeleteIcon(); else if(id==ID_EXIT) OnCancel(); return FALSE;}LRESULT res= CDialog::WindowProc(message, wParam, lParam);if(message==WM_SYSCOMMAND&&wParam==SC_MINIMIZE) AddIcon(); return res;}void CCaptureDlg::AddIcon(){ NOTIFYICONDATA data; data.cbSize=sizeof(NOTIFYICONDATA); CString tip; tip.LoadString(IDS_ICONTIP); data.hIcon=GetIcon(0); data.hWnd=GetSafeHwnd(); strcpy(data.szTip,tip); data.uCallbackMessage=IDM_SHELL; data.uFlags=NIF_ICON|NIF_MESSAGE |NIF_TIP ; data.uID=98; Shell_NotifyIcon(NIM_ADD,&data); ShowWindow(SW_HIDE); bTray=TRUE;}void CCaptureDlg::DeleteIcon(){ NOTIFYICONDATA data; data.cbSize=sizeof(NOTIFYICONDATA); data.hWnd=GetSafeHwnd(); data.uID=98; Shell_NotifyIcon(NIM_DELETE,&data); ShowWindow(SW_SHOW); SetForegroundWindow(); ShowWindow(SW_SHOWNORMAL); bTray=FALSE;}void CCaptureDlg::OnChange() { RegisterHotkey();}BOOL CCaptureDlg::RegisterHotkey(){ UpdateData(); UCHAR mask=0; UCHAR key=0; if(m_bControl) mask|=4; if(m_bAlt) mask|=2; if(m_bShift) mask|=1; key=Key_Table[m_Key.GetCurSel()]; if(bRegistered){ DeleteHotkey(GetSafeHwnd(),cKey,cMask); bRegistered=FALSE; } cMask=mask; cKey=key; bRegistered=AddHotkey(GetSafeHwnd(),cKey,cMask); return bRegistered;} 四、小结 本实例通过一个钩子DLL实现了屏幕抓图的功能，它有一个缺陷，那就是只能保存整个屏幕图像，不过读者朋友可以在此基础上，实现屏幕任意区域的抓图功能，具体方法不再赘述，实现起来很容易的了，呵呵。 |
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