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:
I_N"mnn@Nr
G!%1<SLi. 一、实现方法
I'J=I{p* /I: d<A 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:
u\>Ed9^ ^${-^w@,%V #pragma data_seg("shareddata")
011 _(v HHOOK hHook =NULL; //钩子句柄
ptrLnJ|% UINT nHookCount =0; //挂接的程序数目
<y~`J`- static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Lt=#tu&d static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
AvhmN5O= static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
{Uu7 @1@n static int KeyCount =0;
tpA7"JD static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
u5%.T0
P #pragma data_seg()
l6)*u[}E i1u &-#k 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
d(R3![: {s4:V=J DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
[|uAfp5R <L:v2 8c BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
6`F_js.a cKey,UCHAR cMask)
{8b6A~/ {
+-HaYB|p BOOL bAdded=FALSE;
`N2zeFG for(int index=0;index<MAX_KEY;index++){
5Ss=z if(hCallWnd[index]==0){
.wYx_ hCallWnd[index]=hWnd;
%z1WdiC HotKey[index]=cKey;
IOt!A HotKeyMask[index]=cMask;
RM QlciG bAdded=TRUE;
[ bE9Y; KeyCount++;
-s4qm)\ break;
zn@tLLX }
R (4 :_ xc }
{Pu\KRU return bAdded;
_?`3zm4 }
(;cbgHo%} //删除热键
%vn rLt$ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
fE7[Sk {
GT2;o BOOL bRemoved=FALSE;
;V`~'357% for(int index=0;index<MAX_KEY;index++){
C %y AMQ if(hCallWnd[index]==hWnd){
NCX!ss if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
6-<,1Q'D hCallWnd[index]=NULL;
Gz$DsaG HotKey[index]=0;
;nSaZ$`5 HotKeyMask[index]=0;
T3!l{vG
\O bRemoved=TRUE;
"l2_7ZXsPT KeyCount--;
x@ (91f break;
@ttcFX1:W }
5-aCNAF2 }
Q!|. ,?V }
rOH8W return bRemoved;
I)9;4lix }
+g\u=&<6 a+,)rY9 6BNOF66kH DLL中的钩子函数如下:
~ia#=|1} a)[t kjU LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
0;r+E*`DA {
- C8h$P BOOL bProcessed=FALSE;
(F~eknJ if(HC_ACTION==nCode)
T?NwSxGo {
q'd6\G0} if((lParam&0xc0000000)==0xc0000000){// 有键松开
"k5 C? ~ switch(wParam)
?OlYJ/!z3 {
]D%D:>9|/ case VK_MENU:
<-X)<k MaskBits&=~ALTBIT;
($[pCdY break;
GS \- case VK_CONTROL:
0t6s20*q MaskBits&=~CTRLBIT;
Kx$?IxZ break;
(m~MyT#S case VK_SHIFT:
+X"TiA7{j MaskBits&=~SHIFTBIT;
6e/ 2X<O break;
4s.wQ2m default: //judge the key and send message
X -6Se break;
=-`X61];M }
`N
;!=7y7Y for(int index=0;index<MAX_KEY;index++){
p*n$iroy_{ if(hCallWnd[index]==NULL)
,$7LMTVDrE continue;
e2k!5OS if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
_sJp"4? {
3-~_F*%ST SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
]:Ocu--
bProcessed=TRUE;
J1P82=$, }
{Km|SG[-q }
XR]]g+Z }
.lTU[(qwu else if((lParam&0xc000ffff)==1){ //有键按下
+TA(crD switch(wParam)
q1`uS^3` {
7H++ pOF case VK_MENU:
Q->'e-\E<" MaskBits|=ALTBIT;
~\Fde^1 break;
&I <R|a case VK_CONTROL:
2mVH*\D MaskBits|=CTRLBIT;
o7&Z4(V break;
!5Z?D8dcx case VK_SHIFT:
J6rXbui$ MaskBits|=SHIFTBIT;
:G,GHU'/78 break;
rOS fDv default: //judge the key and send message
zxTm`Dh;[ break;
xL=g(FN(6L }
U~!97,|ic for(int index=0;index<MAX_KEY;index++){
fh:=ja?bM3 if(hCallWnd[index]==NULL)
X
NnsMl continue;
**dGK_^T0 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
mWta B>f {
hFs0qPVY SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
u,4,s[ bProcessed=TRUE;
,TeDJ\k }
^ D?;K8a-l }
_Ev"/% }
X*}S(9cg\i if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
&h8+- for(int index=0;index<MAX_KEY;index++){
M'R^?Jjb if(hCallWnd[index]==NULL)
cD-\fRBGK continue;
5H""_uw if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
C7eaioW$ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
0 l
G\QT //lParam的意义可看MSDN中WM_KEYDOWN部分
^kt#[N }
DZ(e^vq }
X}h{xl }
c|hKo[r) return CallNextHookEx( hHook, nCode, wParam, lParam );
Xj?j1R>GB }
ezC55nm E!C~*l]wJx 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:
jFbz:aUF Eki7bT@/ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
@_h/%>0 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
nYTI\f/8v 6pxj9@X+ 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:
S!up2OseW `"Tx%>E(U LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
3,S5>~R= {
OBF5Tl4 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
\[+ZKj: {
#oJ9BgDry //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
akrEZ7A SaveBmp();
N;;!ObVHnP return FALSE;
Z!^iPB0~D }
d+[hB4!l2 …… //其它处理及默认处理
YmNBtGhT }
WVf;uob{ @;JT }R H- 33s.p' 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。
5 S7\m5 P=(\3ok 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。
adHHnH`, _+.z2} M 二、编程步骤
b?h"a<7 r6*0H/* 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";
i,$*+2Z D{PO!WzW 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
u` R _lu.@IX- 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;
GriL< =?t CIYTs,u# 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;
kplyZ y=G 5、 添加代码,编译运行程序。
|!flR? OU wNcf7/ky 三、程序代码
11%^K=dq )xT_RBR ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
|A[Le
;, #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
-8#Of)W #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
;UArDw H #if _MSC_VER > 1000
OAc+LdT #pragma once
r}pYm'e #endif // _MSC_VER > 1000
pc:~_6S #ifndef __AFXWIN_H__
0waQw7
E #error include 'stdafx.h' before including this file for PCH
[1G4he% #endif
DLJu%5F #include "resource.h" // main symbols
Y[
a$~n^:n class CHookApp : public CWinApp
Vdh5s 292h {
&NB[:S= public:
Ag#p ) CHookApp();
W5HC7o\4 // Overrides
<G}>Gk8x // ClassWizard generated virtual function overrides
'!b1~+PV //{{AFX_VIRTUAL(CHookApp)
Nq9@^ E-{M public:
=uMoX
- virtual BOOL InitInstance();
L&. 9.Ll virtual int ExitInstance();
E{(7]Wri //}}AFX_VIRTUAL
pN1W|Wv2 //{{AFX_MSG(CHookApp)
xzAyE5GL> // NOTE - the ClassWizard will add and remove member functions here.
`:R8~>p // DO NOT EDIT what you see in these blocks of generated code !
gX.4I; //}}AFX_MSG
}Q/xBC) DECLARE_MESSAGE_MAP()
JY4 +MApN };
QE m6#y LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
Z_ak4C BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
#e{l:!uS\ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
bCy.S.`jHQ BOOL InitHotkey();
F3;UH%L1 BOOL UnInit();
:
v<|y F #endif
3{]csZvW cRI&cN"o //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
!n@Yg2 w #include "stdafx.h"
Ro$l/lXl8t #include "hook.h"
f*aYS #include <windowsx.h>
b:+.Y$%F- #ifdef _DEBUG
j^Bo0{{ #define new DEBUG_NEW
?2aglj*"v, #undef THIS_FILE
||0mfb static char THIS_FILE[] = __FILE__;
SB:-zQ5 #endif
kOs_] #define MAX_KEY 100
M(jSv #define CTRLBIT 0x04
[qI, $ + #define ALTBIT 0x02
!QSL8v@c #define SHIFTBIT 0x01
Jx.Jx~ #pragma data_seg("shareddata")
Y'DI@ HHOOK hHook =NULL;
?2E@)7 UINT nHookCount =0;
N0vr>e` static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
K*d+pImrV static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
\L<Hy)l static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
Pz:,q~ static int KeyCount =0;
LW{7|g static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
9V9K3xWn #pragma data_seg()
Kn?>XXAc HINSTANCE hins;
oDrfzm|[Y void VerifyWindow();
!w(J]< BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
;mjk`6p //{{AFX_MSG_MAP(CHookApp)
[K9l>O // NOTE - the ClassWizard will add and remove mapping macros here.
LeF Z%y)F // DO NOT EDIT what you see in these blocks of generated code!
Z[[qW
f //}}AFX_MSG_MAP
)4bBR@QM END_MESSAGE_MAP()
jL<:N
8 "fU=W|lY CHookApp::CHookApp()
B#OnooJI {
&l/2[>D%4 // TODO: add construction code here,
&&nvv &a // Place all significant initialization in InitInstance
hV)D,oN3 }
}N&}6U SRRqIQz CHookApp theApp;
!NuiVC] LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
LkK%DY {
Tu o`>ZA BOOL bProcessed=FALSE;
I~-W4{ if(HC_ACTION==nCode)
@4#q {
0r*E$|zZ if((lParam&0xc0000000)==0xc0000000){// Key up
onI%Jl sq switch(wParam)
iV58 m {
^KM' O8 case VK_MENU:
wDVKp[' MaskBits&=~ALTBIT;
&CpxD."8x break;
G%jgr"]\z case VK_CONTROL:
'JU(2mF MaskBits&=~CTRLBIT;
nm`[\3R break;
M ~zA case VK_SHIFT:
!ow:P8K? MaskBits&=~SHIFTBIT;
07P/A^Mkx break;
{E@Fk, default: //judge the key and send message
%M]%[4eC break;
="Zr. g~8 }
gFizw:l for(int index=0;index<MAX_KEY;index++){
GL-v</2'U if(hCallWnd[index]==NULL)
:PE{2* continue;
Qz=F
nR if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
WYSqnmi {
opU=49b SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
@.0>gmY;: bProcessed=TRUE;
Fku~'30 }
Z-z^0QO }
N?hQ53#3 }
* ?x$q/a else if((lParam&0xc000ffff)==1){ //Key down
zl^ %x1G switch(wParam)
&kUEnwQ- {
`<2k.aW4e8 case VK_MENU:
Q3[MzIk 4 MaskBits|=ALTBIT;
=(2y$,6g? break;
I$7|?8 case VK_CONTROL:
b"Hc==` MaskBits|=CTRLBIT;
\@&oK2f break;
"\cDSiD case VK_SHIFT:
JZI)jIh MaskBits|=SHIFTBIT;
2[
=
=
break;
DA]<30w default: //judge the key and send message
(VV5SvdE break;
6
<XQ'tM]N }
N-Fs-uB for(int index=0;index<MAX_KEY;index++)
h;cl+c|B {
-FpZZ8=,M2 if(hCallWnd[index]==NULL)
-@L7!,j continue;
tg-U x if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
IJa6W`} {
17P5Dr& SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
q)te/J@ bProcessed=TRUE;
E)sC:oO }
J=7.-R|t }
u_H=Xm)9 }
Z*/{^ zsE if(!bProcessed){
-Pt. for(int index=0;index<MAX_KEY;index++){
\]<eLw-v if(hCallWnd[index]==NULL)
*U>"_h T0 continue;
qW+'#Jh@TV if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
%hDx UZ#0 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
nilis-Bk_ }
I]Ev6>=; }
Q\Wh]=} }
mxD]`F return CallNextHookEx( hHook, nCode, wParam, lParam );
K|L&mL&8 }
=r|e]4 idsBw!DB BOOL InitHotkey()
!ZNirvk {
J([Y4Em5 if(hHook!=NULL){
Y*VF1M,2_ nHookCount++;
:m.6a4vx return TRUE;
)R6h
1 }
=z>d GIT1 else
+FomAs1*f hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
jkAWRpOc) if(hHook!=NULL)
]31>0yj[Q nHookCount++;
4.Kl/b; return (hHook!=NULL);
9*~bAgkWI }
I]GGmN BOOL UnInit()
!0-KB# {
u00w'=pe) if(nHookCount>1){
Ic2Q<V}oq nHookCount--;
3JYhF)G return TRUE;
7N:3 }
TOT#l6yqdd BOOL unhooked = UnhookWindowsHookEx(hHook);
M(
w'TE@ if(unhooked==TRUE){
O06 2c)vIY nHookCount=0;
/U$5'BoS hHook=NULL;
,3XlX(P }
6v"WI@b4 return unhooked;
'/="bSF }
[~NJf3c" A@uU*]TqJ8 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
f/7on|bv {
&u`EYxT BOOL bAdded=FALSE;
)J^5?A for(int index=0;index<MAX_KEY;index++){
@7HHi~1JK if(hCallWnd[index]==0){
F8H4R7
8>; hCallWnd[index]=hWnd;
8:t!m>(* HotKey[index]=cKey;
c,CcKy;+ HotKeyMask[index]=cMask;
<)$&V*\ bAdded=TRUE;
jOUM+QO KeyCount++;
1.0: break;
a =
*' }
Ztl?*zL }
s(Y2]X4
( return bAdded;
$E/N }
}~NM\rm CCHGd&\Z BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Nl]_Ie6 {
aD^jlt BOOL bRemoved=FALSE;
NufRd/q for(int index=0;index<MAX_KEY;index++){
="p,~ivrz if(hCallWnd[index]==hWnd){
}j$tFFVi~ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
MgO_gFr hCallWnd[index]=NULL;
<
]"Uy p HotKey[index]=0;
bL`>#M_^ HotKeyMask[index]=0;
;n q"jm bRemoved=TRUE;
bvW3[ V KeyCount--;
,(i`gH{D break;
q2b>Z6!5 }
8vkCmV }
>,x&L[3 }
'yo-`nNFD return bRemoved;
T mK[^ }
K
0e*K=UM |.KB void VerifyWindow()
|.z4 VJi4 {
{uDH-b(R for(int i=0;i<MAX_KEY;i++){
qTrM*/m:]L if(hCallWnd
!=NULL){ 8-_atL
if(!IsWindow(hCallWnd)){ .],:pL9d
hCallWnd=NULL; *Sg6VGP
HotKey=0; 4|&_i)S-Y
HotKeyMask=0; ::p%R@?
KeyCount--; QE|x[?7e,!
} (gRTSd T?
} LC7%Bfn!
} o2D;EUsNX
} ,|g&v/WlC%
x)jc
BOOL CHookApp::InitInstance() ?8qN8rk^+
{ %Rt
5$+dNT
AFX_MANAGE_STATE(AfxGetStaticModuleState());
:yw8_D3
hins=AfxGetInstanceHandle(); "!Qi$ ]
InitHotkey(); b@S~
=
return CWinApp::InitInstance(); 7{tU'`P>
} wg+[T;0 S
-FF#+Z$
int CHookApp::ExitInstance() <(t{C8>g%
{ bt*
VerifyWindow(); o@ m7@$7
UnInit(); !K-qoBqKM
return CWinApp::ExitInstance(); X$Shi
*U[
} N\"Hf=Y(~
X?YT>+g;
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file % *ng *
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 'l<