<br>大富翁论坛版权所有<br> 问题:求Delphi版屏幕取词源代码,200分 ( 积分:200, 回复:4, 阅读:21 )<br>分类:Windows API ( 版主:amo, cAkk ) <br>来自:fevath, 时间:2002-3-22 3:13:00, ID:996179 [显示:小字体 | 大字体] <br>要那个截获TextOut的,要能工作的。<br>将截获的字(单个汉字)同时显示在调用程序的标题栏上即可(或者动态链接库自己处理,<br>显示在鼠标下方更好,如果这样我在加50分)<br> <br> <br>来自:zhihuali, 时间:2002-3-22 3:40:00, ID:996181 <br>转载:<br>-----------------------------------------------------------<br>1、添加form,在上面添加一个richedit,名字叫rich1<br>2、在form的onload事件中往rich1里面随便添加一段文字做测试用:<br>procedure TForm1.FormCreate(Sender: TObject);<br>begin<br> rich1.Lines.Add('cAkk is a good boy');<br>end;<br><br>3、定义rich1的onmousemove事件:<br>procedure TForm1.rich1MouseMove(Sender: TObject; Shift: TShiftState; X,Y: Integer);<br>var txt:String;<br>begin<br> txt:= RichWordOver(rich1, X, Y);<br> //截词结果显示在form的caption上<br> If Caption <> txt Then<br> Caption:= txt;<br>end;<br><br>4、定义函数RichWordOver<br><br>Function TForm1.RichWordOver(rch:trichedit; X,Y:integer):string;<br>var pt:tpoint;<br> pos,<br> start_pos,<br> end_pos:Integer;<br> ch,txt:String;<br> txtlen:Integer;<br>begin<br><br> pt.X:= X;<br> pt.Y:= Y;<br> pos:=rch.Perform(EM_CHARFROMPOS, 0, longint(@pt));<br> If pos <= 0 Then Exit;<br> txt:= rch.Text;<br> For start_pos:= pos downTo 1 do<br> begin<br> ch:=copy(rch.text,start_pos, 1);<br> If Not (<br> ( (ch >= '0') And (ch <= '9') ) Or<br> ( (ch >= 'a') And (ch <= 'z') ) Or<br> ( (ch >= 'A') And (ch <= 'Z') ) Or<br> (ch = '_')<br> ) Then break;<br> end;<br><br> inc(start_pos);<br><br> txtlen:= Length(txt);<br> For end_pos:= pos To txtlen do<br> begin<br> ch:= copy(txt, end_pos, 1);<br> If Not (<br> ( (ch >= '0') And (ch <= '9') ) Or<br> ( (ch >= 'a') And (ch <= 'z') ) Or<br> ( (ch >= 'A') And (ch <= 'Z') ) Or<br> (ch = '_')<br> ) Then break;<br> end;<br> dec(end_pos);<br><br> If start_pos <= end_pos Then<br> result:=copy(txt, start_pos, end_pos - start_pos + 1);<br>End;<br><br> <br> <br>来自:fevath, 时间:2002-3-22 7:16:00, ID:996197 <br>那么取非客户区的文字呢,我要监控整个系统,HOOK我已经做好了,只是不知道如何截获<br>TEXTOUT并获得其参数。不好意思ZhiHuaLi我想可能是我的问题问的可能不太清楚……<br> <br> <br>来自:jrq, 时间:2002-3-22 8:09:00, ID:996224 <br>>>HOOK我已经做好了<br>你可以将钩子编译为DLL~<br><br>下面是一个取词的源码:--转载 [
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]<br>这是dll文件:<br>library dll_HookMouse;<br>uses<br> SysUtils,<br> Windows,<br> Classes,<br> Messages,<br> Math,<br> Dialogs,<br> U_Def in 'U_Def.pas';<br>{$R *.RES}<br>var<br> hMouseHook : HHOOK;<br> SpyInstalled : Boolean;<br> fTimerID : Cardinal;<br> pShMem : PShareMem;<br> hMappingFile : THandle;<br>function InstallSpy:Boolean; forward;<br>function UnWiseSpy:Boolean; forward;<br>function fExtTextOutA(theDC :HDC; nXStart, nYStart :integer; toOptions : Lon<br>gint; rect : PRect;<br> lpStr
AnsiChar; nCount :Longint; Dx: PInteger):BOOL;<br> stdcall;<br>var<br> dwBytes, dwCallingProc : DWORD;<br> pOldExtTextOut : _ExtTextOutA;<br> hModuleGDI : THandle;<br> poOri, poDC, poText, poMouse : TPoint;<br> Size : TSize;<br>begin<br> UnWiseSpy;<br> GetWindowThreadProcessID(pShMem^.hHookWnd, @dwCallingProc);<br> try<br> if pShMem^.bCanSpyNow and (dwCallingProc <> pShMem^.hProc) then<br> begin<br> dwBytes := Min(nCount, MaxStringLen);<br> CopyMemory(@(pShMem^.fStrExtTextOutA), lpStr, dwBytes);<br> //Get lpStr Content<br> //The following codes for get the right text<br> GetDCOrgEx(theDC, poOri);<br> // 取得本窗口设备相关坐标原点的全局逻辑坐标<br> poDC.x := nXStart;<br> poDC.y := nYStart;<br> //<br> LPToDP(theDC, poDC, 1);<br> //全局逻辑坐标转化为设备相关坐标<br> GetCursorPos(poMouse);<br> poText.x := poDC.x + poOri.x;<br> poText.y := poDC.y + poOri.y;<br> if (GetTextAlign(theDC) and TA_UPDATECP) <> 0 then<br> begin<br> GetCurrentPositionEx(theDC, @poOri);<br> poText.x := poText.x + poOri.x;<br> poText.y := poText.y + poOri.y;<br> end;<br> GetTextExtentPoint(theDC, lpStr, nCount, Size);<br> // 取得要输出的字符串的实际显示大小<br> if (poMouse.x >= poText.x) and (poMouse.x <= poText.x + Size.cx) and<br> (poMouse.y >= poText.y) and (poMouse.y <= poText.y + Size.cy) then<br> begin<br> pShMem^.bCanSpyNow := False;<br> pShMem^.nTimePassed := -1;<br> end;<br> pShMem^.fStrExtTextOutA[dwBytes] := Chr(0);<br> FlushViewOfFile(pShMem, 0);<br> if dwCallingProc <> pShMem^.hProc then<br> PostMessage(pShMem^.hProcWnd, WM_MOUSEPT, 2, 2);<br> end;<br> if (dwCallingProc = pShMem^.hProc) or pShMem^.bHookExtTextOutA then<br> begin<br> hModuleGDI := GetModuleHandle(PChar('GDI32'));<br> @pOldExtTextOut := GetProcAddress(hModuleGDI, PChar('ExtTextOutA'));<br> Result := pOldExtTextOut(theDC, nXStart, nYStart, toOptions, rect, lpS<br>tr, nCount, Dx);<br> end else<br> Result := True;<br> except<br> Result := False;<br> end;<br> SpyInstalled := True;<br> InstallSpy;<br>end;<br>function UnWiseSpy:Boolean;<br>var<br> dwBytesWritten, dwOldProtect : DWORD;<br> pOldExtTextOut : _ExtTextOutA;<br> hModuleGDI : THandle;<br>begin<br> hModuleGDI := GetModuleHandle(PChar('GDI32'));<br> @pOldExtTextOut := GetProcAddress(hModuleGDI, PChar('ExtTextOutA'));<br> if not VirtualProtect(@pOldExtTextOut, SizeOf(TLongJump), PAGE_EXECUTE_REA<br>DWRITE, @dwOldProtect) then<br> begin<br> Result := False;<br> Exit;<br> end;<br> if not WriteProcessMemory(GetCurrentProcess, @pOldExtTextOut, @pShMem^.pOl<br>dExtTextOutA, SizeOf(TLongJump), dwBytesWritten) then<br> begin<br> Result := False;<br> Exit;<br> end;<br> if not VirtualProtect(@pOldExtTextOut, SizeOf(TLongJump), dwOldProtect, @d<br>wBytesWritten) then<br> begin<br> Result := False;<br> Exit;<br> end;<br> Result := True;<br>end;<br>function InstallSpy:Boolean;<br>var<br> dwBytesWritten, dwOldProtect : DWORD;<br> ljHere : TLongJump;<br> pOldExtTextOut : _ExtTextOutA;<br> hModuleGDI : THandle;<br>begin<br> hModuleGDI := GetModuleHandle(PChar('GDI32'));<br> @pOldExtTextOut := GetProcAddress(hModuleGDI, PChar('ExtTextOutA'));<br> if not VirtualProtect(@pOldExtTextOut, SizeOf(TLongJump), PAGE_EXECUTE_REA<br>DWRITE, @dwOldProtect) then<br> begin<br> Result := False;<br> Exit;<br> end;<br> ljHere.JmpOp := CodeJump;<br> ljHere.Addr := Pointer( Cardinal(@fExtTextOutA) - Cardinal(@pOldExtTextOut<br>) - SizeOf(TLongJump) );<br> if not WriteProcessMemory(GetCurrentProcess, @pOldExtTextOut, @ljHere, Siz<br>eOf(TLongJump), dwBytesWritten) then<br> begin<br> Result := False;<br> Exit;<br> end;<br> if not VirtualProtect(@pOldExtTextOut, SizeOf(TLongJump), dwOldProtect, @d<br>wBytesWritten) then<br> begin<br> Result := False;<br> Exit;<br> end;<br> Result := True;<br>end;<br>function MouseHookProc(nCode : integer; wPar : WParam; lPar : LParam) : lRes<br>ult; stdcall;<br>var<br> pMouseInf : TMouseHookStruct;<br>begin<br> if (not SpyInstalled) and pShMem^.bHookExtTextOutA then<br> InstallSpy;<br> if SpyInstalled and (not pShMem^.bHookExtTextOutA) then<br> begin<br> UnwiseSpy;<br> SpyInstalled := False;<br> end;<br> pShMem^.nTimePassed := 0 ;<br> if (nCode >= 0) and (wPar = WM_MOUSEMOVE) then<br> begin<br> pMouseInf := (PMouseHookStruct(lPar))^;<br> if (pShMem^.pMouse.x <> pMouseInf.pt.x) or<br> (pShMem^.pMouse.y <> pMouseInf.pt.y) then<br> begin<br> if nCode = HC_NOREMOVE then<br> pShMem^.fStrMouseQueue := 'Not removed from the queue'<br> else //then HC_ACTION<br> pShMem^.fStrMouseQueue := 'Removed from the queue';<br> pShMem^.pMouse := pMouseInf.pt;<br> pShMem^.hHookWnd := pMouseInf.hwnd;<br> PostMessage(pShMem^.hProcWnd, WM_MOUSEPT, 1, 1); //1 indicates mouse m<br>essage<br> end;<br> end;<br> FlushViewOfFile(pShMem, 0);<br> Result := CallNextHookEx(hMouseHook, nCode, wPar, lPar);<br>end;<br>procedure fOnTimer(theWnd : HWND; msg, idTimer : Cardinal; dwTime : DWORD);f<br>ar pascal; //CallBack Type<br>begin<br> if pShMem^.nTimePassed = -1 then<br> Exit;<br> pShMem^.nTimePassed := pShMem^.nTimePassed + 1;<br> if pShMem^.nTimePassed > 21 then<br> begin<br> pShMem^.nTimePassed := 21;<br> FlushViewOfFile(pShMem, 0);<br> Exit;<br> end;<br> if pShMem^.nTimePassed > 20 then<br> begin<br> pShMem^.bCanSpyNow := True;<br> FlushViewOfFile(pShMem, 0);<br> SetWindowPos(pShMem^.hWndPseudo, HWND_TOPMOST, pShMem^.pMouse.x, pShMem^<br>.pMouse.y, 1, 8, SWP_NOACTIVATE or SWP_SHOWWINDOW);<br> ShowWindow(pShMem^.hWndPseudo , SW_HIDE);<br> end;<br>end;<br>function MouseWndProc(theWnd : HWND; theMess : Cardinal; wPar : wParam; lPar<br> : lParam): LResult;stdcall;<br>begin<br> case theMess of<br> WM_CLOSE :<br> begin<br> DestroyWindow(theWnd);<br> PostQuitMessage(0);<br> end;<br> else<br> begin<br> Result := DefWindowProc(theWnd, theMess, wPar, lPar);<br> Exit;<br> end;<br> end;<br> Result := 0;<br>end;<br>function InstallMouseHook(hInst : LongWord):Boolean;<br>begin<br> hMouseHook := SetWindowsHookEx(WH_MOUSE,<br> MouseHookProc,<br> GetModuleHandle(PChar('dll_HookMouse')),<br> 0);<br> if hMouseHook = 0 then<br> begin<br> Result := False;<br> Exit;<br> end;<br> pShMem^.hWndPseudo := CreateWindowEx(WS_EX_TOPMOST or WS_EX_TOOLWINDOW,<br> 'ZL_MOUSE_WND_PSEUDO',<br> 'ZL_MOUSE_WND_PSEUDO',<br> WS_CLIPSIBLINGS or WS_POPUP ,<br> 0, 0, 1, 8,<br> 0, 0,<br> hInst,<br> nil);<br> ShowWindow(pShMem^.hWndPseudo, SW_HIDE);<br> UpdateWindow(pShMem^.hWndPseudo);<br> fTimerID := SetTimer(0, 0, 10, @fOnTimer);<br> FlushViewOfFile(pShMem, 0);<br> Result := True;<br>end;<br>function UnWiseMouseHook:Boolean;<br>begin<br> KillTimer(0, fTimerID);<br> DestroyWindow(pShMem^.hWndPseudo);<br> if SpyInstalled then<br> UnWiseSpy;<br> pShMem^.bHookExtTextOutA := False;<br> FlushViewOfFile(pShMem, 0);<br> Result := UnHookWindowsHookEx(hMouseHook);<br>end;<br>procedure DllEntry(nReason : integer);<br>begin<br> case nReason Of<br> DLL_PROCESS_ATTACH:<br> begin<br> hMappingFile := CreateFileMapping($FFFFFFFF,<br> nil,<br> PAGE_READWRITE,<br> 0,<br> SizeOf(TShareMem),<br> PChar(MappingFileName));<br> if hMappingFile<>0 then //if h..=0 , the work is done by OS<br> begin<br> pShMem := PShareMem( MapViewOfFile(hMappingFile,<br> FILE_MAP_WRITE,<br> 0, //hi_order offset where mapp<br>ing begins<br> 0, //lo_order offset where mapp<br>ing begins<br> 0) ); //Size of the mapping<br> if pShMem = nil then<br> begin<br> CloseHandle(hMappingFile);<br> ShowMessage('Cannot create the Share Memory Block!');<br> end;<br> end else<br> ShowMessage('Cannot create the Share Memory Block!');<br> end;<br> DLL_PROCESS_DETACH:<br> begin<br> UnwiseSpy;<br> UnMapViewOfFile(pShMem);<br> CloseHandle(hMappingFile);<br> end;<br> else;<br> end;<br>end;<br>exports<br> MouseWndProc,<br> InstallMouseHook,<br> UnWiseMouseHook;<br>begin<br> DllProc := @DllEntry;<br> DllEntry(DLL_PROCESS_ATTACH);<br>end.<br>-------------- ----------------<br>下面是dll的接口文件:<br>unit U_Def;<br>interface<br>uses<br> Messages, Windows;<br>const<br> WM_MOUSEPT = WM_USER + 1000 + Ord('M') + Ord('P') + Ord('T');<br> MappingFileName = 'Mapping File By Raphael';<br> MaxStringLen = 50;<br> CodeJump = $E9909090;<br>type<br> PInt = ^integer;<br> _ExtTextOutA = function (theDC :HDC; nXStart, nYStart :integer; toOptions <br>: Longint; rect : PRect;<br> lpStr
AnsiChar; nCount :integer; Dx : PInteger)<br>:BOOL; stdcall;<br> _PExtTextOutA = ^_ExtTextOutA;<br> TLongJump = packed record<br> JmpOp : Cardinal;<br> Addr : Pointer;<br> end;<br> TShareMem = packed record<br> hProcWnd : HWND; //The main window of the program<br> hHookWnd : HWND; //The window currently being hooked<br> hWndPseudo : HWND; //The pseudo window used to repaint the other<br> window<br> hProc : THandle; //The process ID of the main program<br> pMouse : TPoint; //the mouse position<br> fStrMouseQueue : array [0..MaxStringLen] of Char; //mouse info<br> nTimePassed : integer; //the time passed since last time's mousemove<br><br> bCanSpyNow : Boolean;<br> bHookExtTextOutA : Boolean;<br> pOldExtTextOutA : TLongJump;<br> fStrExtTextOutA : array [0..MaxStringLen] of Char;<br> end;<br> PShareMem = ^TShareMem;<br>implementation<br>end.<br>--------------------<br>下面是主窗体文件:<br>unit U_MouseHook;<br>interface<br>uses<br> Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,<br> StdCtrls, U_Def;<br>type<br> TF_MouseHook = class(TForm)<br> Label1: TLabel;<br> e_MouseInfo: TEdit;<br> btn_HookMouse: TButton;<br> Label2: TLabel;<br> e_ExtTextOutA: TEdit;<br> btn_HookExtTextOutA: TButton;<br> procedure btn_HookMouseClick(Sender: TObject);<br> procedure FormCreate(Sender: TObject);<br> procedure FormClose(Sender: TObject; var Action: TCloseAction);<br> procedure btn_HookExtTextOutAClick(Sender: TObject);<br> private<br> fWndClosed, fbMouseHookInstalled : Boolean;<br> hMapObj : THandle;<br> pShMem : PShareMem;<br> procedure getMouseInfo(var theMess:TMessage); message WM_MOUSEPT;<br> public<br> { Public declarations }<br> end;<br>function InstallMouseHook(hInst : LongWord) : Boolean; external 'dll_HookMouse.dll';<br>function UnWiseMouseHook : Boolean; external 'dll_HookMouse.dll';<br>function MouseWndProc(theWnd : HWND; theMess : Cardinal; wPar : wParam; lPar : lParam): LResult; stdcall; external 'dll_HookMouse.dll';<br>var<br> F_MouseHook: TF_MouseHook;<br>implementation<br>{$R *.DFM}<br>procedure TF_MouseHook.btn_HookMouseClick(Sender: TObject);<br>begin<br> if not fbMouseHookInstalled then<br> begin<br> fbMouseHookInstalled := InstallMouseHook(hInstance);<br> if fbMouseHookInstalled then<br> begin<br> btn_HookMouse.Caption := 'Stop!';<br> btn_HookExtTextOutA.Enabled := True;<br> end else<br> ShowMessage('Cannot hook mouse!');<br> end else<br> begin<br> fbMouseHookInstalled := not UnWiseMouseHook;<br> if not fbMouseHookInstalled then<br> begin<br> btn_HookMouse.Caption := 'Hook Mouse';<br> btn_HookExtTextOutA.Enabled := False;<br> btn_HookExtTextOutA.Caption := 'Hook ExtTextOutA';<br> pShMem^.bHookExtTextOutA := False;<br> FlushViewOfFile(pShMem, 0);<br> end else<br> ShowMessage('Cannot unhook mouse!');<br> end;<br>end;<br>procedure TF_MouseHook.getMouseInfo(var theMess : TMessage);<br>begin<br> if fWndClosed then<br> Exit;<br> if theMess.LParam = 1 then //Get the Mouse info to display<br> e_MouseInfo.Text := 'X:' + IntToStr(pShMem^.pMouse.x) + ' ' +<br> 'Y:' + IntToStr(pShMem^.pMouse.y) + ' ' +<br> 'HWND:0x' + IntToHex(pShMem^.hHookWnd, 8) + ' ' +<br> pShMem^.fStrMouseQueue<br> else if theMess.LParam = 2 then //Get the ExtTextOutA display<br> e_ExtTextOutA.Text := pShMem^.fStrExtTextOutA;<br>end;<br><br><br>procedure TF_MouseHook.FormCreate(Sender: TObject);<br>var<br> hModuleGDI : THandle;<br> wc : TWndClass;<br>begin<br> hMapObj := OpenFileMapping(FILE_MAP_WRITE, //Get full access of the mapping file<br> False, //Not inheritable<br> LPCTSTR(MappingFileName)); //Name of the mapping file<br> if hMapObj = 0 then<br> begin<br> ShowMessage('Cannot locate the Share Memory Block!');<br> Halt;<br> end;<br> pShMem := PShareMem( MapViewOfFile(hMapObj,<br> FILE_MAP_WRITE,<br> 0, //hi_order offset where mapping begins<br> 0, //lo_order offset where mapping begins<br> 0) ); //Size of the mapping<br> if pShMem = nil then<br> begin<br> ShowMessage('Map File Mapping Failed! Error '+ IntToStr(GetLastError));<br> CloseHandle(hMapObj);<br> Halt;<br> end;<br> FillChar(pShMem^, SizeOf(TShareMem), 0);<br> hModuleGDI := GetModuleHandle(PChar('GDI32'));<br> if hModuleGDI = 0 then<br> begin<br> ShowMessage('Cannot get module GDI32! Error ' + IntToStr(GetLastError));<br><br> UnmapViewOfFile(pShMem);<br> CloseHandle(hMapObj);<br> Halt;<br> end;<br> CopyMemory(@pShMem^.pOldExtTextOutA, GetProcAddress(hModuleGDI, PChar('ExtTextOutA')), SizeOf(TLongJump));<br> pShMem^.hProcWnd := Self.Handle;<br> GetWindowThreadProcessID(Self.Handle, @pShMem^.hProc);<br> pShMem^.bHookExtTextOutA := False;<br> pShMem^.bCanSpyNow := False;<br> fbMouseHookInstalled := False;<br> FlushViewOfFile(pShMem, 0);<br> wc.style := 0;<br> wc.lpfnWndProc := TFNWndProc(@MouseWndProc);<br> wc.cbClsExtra := 0;<br> wc.cbWndExtra := 0;<br> wc.hInstance := HInstance;<br> wc.hIcon := 0 ;<br> wc.hCursor := 0 ;<br> wc.hbrBackground := 0 ;<br> wc.lpszMenuName := nil;<br> wc.lpszClassName := 'ZL_MOUSE_WND_PSEUDO';<br> // register the class for the main window<br> Windows.RegisterClass(wc);<br> fWndClosed := False;<br>end;<br><br><br>procedure TF_MouseHook.FormClose(Sender: TObject;<br> var Action: TCloseAction);<br>begin<br> if fbMouseHookInstalled then<br> UnWiseMouseHook;<br> UnMapViewOfFile(pShMem);<br> CloseHandle(hMapObj);<br> Windows.UnRegisterClass('ZL_MOUSE_WND_PSEUDO', hInstance);<br> fWndClosed := True;<br>end;<br>procedure TF_MouseHook.btn_HookExtTextOutAClick(Sender: TObject);<br>begin<br> if pShMem^.bHookExtTextOutA then<br> btn_HookExtTextOutA.Caption := 'Hook ExtTextOutA'<br> else<br> btn_HookExtTextOutA.Caption := 'Stop!';<br> pShMem^.bHookExtTextOutA := not pShMem^.bHookExtTextOutA;<br> FlushViewOfFile(pShMem, 0);<br>end;<br>//RaiseLastWin32Error can be used to create a GetLastError<br>//Message<br>end.<br>---------------------------<br>我做的时候分析了一下,主要用了ExtTextOutA这个API。 <br>可以取词! <br> <br> <br>来自:jrq, 时间:2002-3-22 8:37:00, ID:996282 <br>[
]<br>屏幕抓字技术揭密(转载)<br><br>屏幕抓字技术揭密 <br>----------深入WINDOWS内部探险手记 <br><br>郑州 马飞涛 <br><br>一 公开它! <br><br>四通利方和金山词霸的用户都曾见识过屏幕抓字技术,鼠标指哪就翻译哪个 <br>单 <br><br>词,这个技术看似简单,其实在WINDOWS系统中实现却是非常复杂和有趣的。 经 <br>过 <br><br>半年多的艰辛探索,笔者终于破解了其中的秘密,并在今天决定公开它,这个人 <br>人 <br><br>都曾见过但是却鲜有人知的秘密,这个只被几家软件公司垄断从未在公开的报刊 <br>资 <br><br>料披露过只言片语的秘密! <br>回想这半年多的探索,其中浸润了多少笔者的苦闷与欢乐,绝望与兴奋,挫 <br>折 <br><br>与收获,现在都终于有了结果:将屏幕抓字技术的秘密公开,献给孜孜不倦辛勤 <br>工 <br><br>作的程序员们。如果这样做能为国产软件事业的发展效微薄之力,对笔者来说, <br>也 <br><br>是一桩快事! <br><br>二 初识屏幕抓字 <br><br>最初知道屏幕抓字, 是在购买了〖英汉通〗软件之后。 当时笔者还只是一 <br>个 <br><br>VISUAL BASIC 的初学者, 对 WINDOWS 系统内部的知识了解并不多, 认为 <br>在 <br><br>WINDOWS系统中屏幕抓字的实现应该和DOS系统中的一样,调用一个DOS 中断取屏 <br>幕 <br><br>上的字符或直接读显示内存的内容就可以了。 <br><br>三 看似很简单,其实不然 <br><br>随着对WINDOWS系统的认识不断深入,才发现问题并不象想得那么简单。首先, <br><br>翻阅了WINODWS应用程序接口(API)中的上千个函数,并没有发现有一个现成的 <br>类 <br><br>似于getWordFromPoint()的函数;根据使用经验,经过判断发现屏幕抓字采用的 <br>也 <br><br>不是图像识别技术;翻阅了SDK的联机文档中没有,DDK的联机文档中也没有;显 <br>示 <br><br>卡编程接口的资料则很难获得,有的也只是CGA到VGA显存的基本知识。回想当时 <br>坐 <br><br>在机子前,面对一屏屏的联机资料(如果是纸,将堆积如山),感觉就是在黑暗 <br>中 <br><br>的大海里航行,没有方向,没有灯光,但强烈的兴趣紧抓着我,一定要把这个谜 <br>解 <br><br>开。 <br><br>四 选择合适的编程工具 <br><br>突然又有了一些新的想法: <br>可否试着截获WINDOWS中关于字符的消息呢? <br>DC(设备描述表)到底是什么? <br>WINDOWS的TextOut函数是否将TEXT放在DC的某个单元中? <br>显然,用VISUAL BASIC就力不从心了。在DOS中用TURBO C编程笔者还算熟练 <br>, <br><br>因此先尝试用VISUAL C++,但是奇慢的编译速度使人难以忍受, 高度抽象的类 <br>让 <br><br>人一头雾水,开发商务软件可能还行,但开发这样一个深入WINDOWS 内部的系统 <br>软 <br><br>件,望着一堆缠绕不清的类和消息,真有点牛刀宰鸡、刺刀耕田的感觉。 <br>最后选择了DELPHI,第一印象是编译速度真快,在我的祖父型386 机子上 <br>编 <br><br>译一个WINDOWS程序,速度和用TURBO <br>C的速度感觉差不多,真让人兴奋得爱不释手。 <br>随着不断使用,发觉DELPHI真是一个好的快速开发工具,(快速并不意味着简单 <br>粗 <br><br>糙,而是和WINDOWS系统有混然一体良好接口的表现)让初学者也很容易上手。 <br>调 <br><br>用各种WINDOWS 函数(包括很多未公开的函数)都非常直接迅速,用它来作开发 <br>工 <br><br>具,大有刺刀见红、一剑封喉的痛快感觉。 <br><br>五 山穷水尽疑无路 <br><br>随着对WINDOWS系统了解的深入,我逐渐明白了在向屏幕输出文字时,WINDO <br>WS <br><br>系统仅仅只是对某个应用程序发送WM_PAINT消息,告诉该应用程序窗口用户区已 <br>经 <br><br>“无效”而需要重画。具体的“绘制”工作(选择字体,颜色,文字)由应用程 <br>序 <br><br>完成。 <br>应用程序在处理WM_PAINT消息时,调用BeginPaint和EndPaint来获得和释放 <br>设 <br><br>备描述表,调用DrawText、ExtTextOut、 TextOut等函数在设备描述表中“绘制 <br>” <br><br>文字。 <br>应用程序“绘制”文字, 就象学生(应用程序)奉命(获得 WM_PAINT消息 <br>) <br><br>用老师(WINDOWS)提供的画笔(DrawText ExtTextOut TextOut等) 在黑板上画 <br>画 <br><br>一样,虽然大家能看到画的是什么字,但是画笔作为绘图工具并不知道画的是什 <br>么。 <br><br>老师(WINDOWS)不知道学生(应用程序)到底用什么字体,颜色,画哪些文字。 <br><br> 总之 ,WINDOWS并不知道应用程序“绘制”的是什么。“文字”对 WINDO <br>WS <br><br>来说只是画笔留在黑板(屏幕)上的粉笔印,只是绘画的痕迹。“文字”只存在 <br>于 <br><br>应用程序的模块中,对WINDOWS系统是“不可见”的。 <br>到处走投无路,真想掂5000块钱,跑到“英汉通”公司买回这个秘密。仔细 <br>一 <br><br>想,钱太少,就是多掂10倍,人家也不一定说。 <br><br>六 柳暗花明又一村 <br><br>经过再三考虑,我联想到在DOS系统中编程,会采取改变中断向量地址, 设 <br>置 <br><br>新的中断向量的技术:如果系统调用这个中断,就会先进入新的中断服务程序, <br>然 <br><br>后再调用原来的中断服务程序。 <br>那末,在WINDOWS系统中也采取这种技术,使系统如果调用某个函数, 先进 <br>入 <br><br>一个跟踪函数,取得原函数的参数,再调用原来的函数。听起来是否象病毒传染 <br>和 <br><br>发作?其实很多程序都采用过类似技术。大学毕业设计声卡时我就用过。 <br>至此, 我认识到应该放弃常规的思路, 采取一些技巧, 截获 TextOut <br>、 <br><br>ExtTextOut等函数,使之转向我的跟踪函数,在此查看应用程序(学生)的堆栈 <br>中 <br><br>传递给画笔(TextOut、ExtTextOut等函数)的参数, 从而获得应用程序要在屏 <br>幕 <br><br>上写的“文字”。 <br><br>七 “ 屏幕抓字”的实现 <br><br>1 用SetWindowsHookEx()安装鼠标钩子MouseProc; <br>2 在屏幕上移动鼠标时,系统就会调用鼠标钩子MouseProc; <br>3 进入MouseProc,获得鼠标的坐标(x,y), <br>设置对TextOut()、ExtTextOut()等的跟踪程序, <br>用invalidateRect()告诉系统该点(x,y)“失效”; <br>4 <br>系统发出WM_PAINT消息,指示该点(x,y)处的应用程序重绘“失效”的区域。 <br>5 负责绘制该点()的应用程序在受到 WM_PAINT 消息后, 就有机会调用 <br><br>TextOut()、 ExtTextOut()等函数。 <br>6 调用的函数被拦截进入跟踪程序:设置好了的跟踪程序截获了该次调用, <br>从 <br><br>应用程序的堆栈中取出 该点(x,y)“文字”的指针; <br>7 从应用程序的数据段中将“文字”指针的内容取出,即完成了一次“屏幕 <br>抓 <br><br>字”; <br>8 退出跟踪程序,返回到鼠标钩子MouseProc; <br>9 在MouseProc中解除对TextOut() ExtTextOut()的跟踪; <br>10 退出MouseProc鼠标钩子程序,控制权交给系统。 <br>11 在屏幕上移动鼠标,开始下一次“屏幕抓字”,返回步骤2。 <br><br>八 前景展望 <br>掌握了“屏幕抓字”的技术秘密,稍加改变,我们就可对WINDOWS 系统中 <br>的 <br><br>任意一个函数调用进行动态地拦截、跟踪、修改和恢复,就可让WINDOWS 系统中 <br>的 <br><br>任意一个函数按我们的设想工作,就可构造自己的外挂汉字平台,设计改变字体 <br>的 <br><br>放大镜、改变颜色的变色镜,保护视力的软件视保屏等等。 <br><br>九 后记 <br><br>希望此文能抛砖引玉,为大家编程时能找到捷径,开拓出新的思路; <br>对拦截、跟踪感兴趣的朋友也请来信交流切磋,如需DLL 或“抓字”的源 <br>代 码,敬请 与 mafeitao@371.net 联系; <br>如能得到“四通利方”、“金山词霸”、“英汉通”等公司的教导与指正 , <br><br>笔者不胜感激。<br><br><br>