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:
]2SF9p_
'cZN{ZMWG 一、实现方法
4\otq%Y 1`bl&}6l|E 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:
I s57F4[} IND ]j72 #pragma data_seg("shareddata")
i&Fiq&V)[ HHOOK hHook =NULL; //钩子句柄
9]'&RyH=# UINT nHookCount =0; //挂接的程序数目
{jKI^aC<[ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
V\5 L?} static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
1QqHF$S static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
cW8\d static int KeyCount =0;
F'm(8/A$ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
i{c@S:&@^ #pragma data_seg()
95W?{>
@ h11.'Eej` 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。
%b2oiKSBx? csZc|kDI 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:
<W)u{KS#TY A=5epsB BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
ksR1kvTm cKey,UCHAR cMask)
eet Q}] {
Q4* -wF-P BOOL bAdded=FALSE;
?DV5y|}pj for(int index=0;index<MAX_KEY;index++){
~ Hy,7 if(hCallWnd[index]==0){
5II(mSg8 hCallWnd[index]=hWnd;
2;3f=$3 HotKey[index]=cKey;
=}!Mf' HotKeyMask[index]=cMask;
#uCB)n&. bAdded=TRUE;
[/M^[p KeyCount++;
E6B!+s!] break;
*LC+ PZV@ }
P$GjF-!: }
Mj=$y?d ] return bAdded;
24c ek }
}R4c //删除热键
cE'L% Z BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
;lX(}2tXW {
E.bi05l BOOL bRemoved=FALSE;
bvBHYf:^ for(int index=0;index<MAX_KEY;index++){
siDh="{s if(hCallWnd[index]==hWnd){
13'vH]S$M if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
$
<8~k^ hCallWnd[index]=NULL;
@F*wg HotKey[index]=0;
fl\aqtF HotKeyMask[index]=0;
J8a*s`ik bRemoved=TRUE;
"6ECgyD+E! KeyCount--;
`Mj}md;O" break;
Sw&!y$ed }
0JuD^
}
TJ8E"t*) }
1nknSw# return bRemoved;
{:nQl} }
HmmS(fU g9fq5E<G `Hx~UH) DLL中的钩子函数如下:
,B}I?vN. t>)45<PEw LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
qSCv )S( {
:wqC8&V BOOL bProcessed=FALSE;
F|bYWYED; if(HC_ACTION==nCode)
t+r:"bb {
va|*c22;| if((lParam&0xc0000000)==0xc0000000){// 有键松开
Uh1NO&i.W switch(wParam)
?']h%'Q
{
/e}#'
H
case VK_MENU:
=QJRMF MaskBits&=~ALTBIT;
[k$*4u> break;
CI:^\-z case VK_CONTROL:
Z=5qX2fy1* MaskBits&=~CTRLBIT;
ppIbjt6r break;
S/ywA9~3Q case VK_SHIFT:
g.JN_t5 MaskBits&=~SHIFTBIT;
x"P);su break;
?rX]x8iP default: //judge the key and send message
HS>f1! break;
,6^znOt }
C`jM0Q for(int index=0;index<MAX_KEY;index++){
d'6|: z9c if(hCallWnd[index]==NULL)
w@\vHH.;V continue;
hG~reVNf if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
@Y,7'0U {
#3=P4FUz. SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
?Ucu#UO bProcessed=TRUE;
sd#|3 }
3ss6_xd+ }
^>y@4q B }
2 !"
XzdD else if((lParam&0xc000ffff)==1){ //有键按下
V==z" switch(wParam)
$/1c= Y@ {
f&,{XZ case VK_MENU:
. v@>JZC MaskBits|=ALTBIT;
OX:O^ (-r, break;
qH,l#I\CG case VK_CONTROL:
Fk;oE'"D MaskBits|=CTRLBIT;
{+<P:jbz; break;
2g9G{~,@g case VK_SHIFT:
# {fTgq MaskBits|=SHIFTBIT;
RyB~Lm`ZK% break;
X;F?:Iw \ default: //judge the key and send message
8;Fn7k_Uf break;
V}o n|A }
39F
Of for(int index=0;index<MAX_KEY;index++){
M~*u;vA/ if(hCallWnd[index]==NULL)
|IoB?^_h continue;
IL/Yc1 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
-F"QEL# {
Rv,JU6>i SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
I
V%VU bProcessed=TRUE;
)Rat0$6 }
9mc!bj^811 }
R2L;bGI*J }
./j,Z$| if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
|wEN`#.;b for(int index=0;index<MAX_KEY;index++){
o'~5pS(wq if(hCallWnd[index]==NULL)
-V"22sR] continue;
K
]OK:hY4 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Uawpfgc} SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
$GQ`clj< //lParam的意义可看MSDN中WM_KEYDOWN部分
_sE#)@p }
@;xMs8@ }
I|-p3g8\ }
?; YC'bF return CallNextHookEx( hHook, nCode, wParam, lParam );
Ll4bdz, }
C'=k<- !|q<E0@w\ 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
%S`
v!*2 YJS{i BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
&bz:K8c BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
1pv}]&X o~FRF0f*VP 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
'Djm0 *tOG*hwdT LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
'/Bidb? {
UmnE@H"t$\ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
!{n<K:x1 {
6J~12TU, //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
o[ENp'r SaveBmp();
O<)y-nx;X return FALSE;
22<0DhJ }
ki0V8]HP …… //其它处理及默认处理
MF60-VE }
FEPXuCb "xMD,}+5$$ &bqT/H18 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。
}7G8|54t MC0TaP 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。
dt[k\ !-v mDGn:oRj 二、编程步骤
@cRZk`|1n P X;Ed*y 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";
/:<IIqO. _UE)*l m+ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
z|?R/Gf8 hqk}akXt 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;
h=kQ$`j6 iyVB3:M 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
0w'j+ gef6pfV 5、 添加代码,编译运行程序。
/sR%]q
|L j`
E +qk 三、程序代码
sC00un% S~qZr ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
d0hhMx6$ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
Y
$g$x<7 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
p\C%% #if _MSC_VER > 1000
Obw?_@X #pragma once
Z3;!l #endif // _MSC_VER > 1000
C 8#@+ Q. #ifndef __AFXWIN_H__
~9F ,% #error include 'stdafx.h' before including this file for PCH
4E8JT#& #endif
Xd:7"/:r #include "resource.h" // main symbols
M,j(=hRJ/E class CHookApp : public CWinApp
zPEg {
juAMAplf public:
dX8hpQ CHookApp();
#B'aU#$u // Overrides
+ SZYg[ // ClassWizard generated virtual function overrides
5_0(D;Q //{{AFX_VIRTUAL(CHookApp)
&X9Z
W$C public:
xRuFuf8 virtual BOOL InitInstance();
C
]Si|D virtual int ExitInstance();
6m .k;' //}}AFX_VIRTUAL
~,D@8tv //{{AFX_MSG(CHookApp)
p3ISWJa! // NOTE - the ClassWizard will add and remove member functions here.
`"i Y* // DO NOT EDIT what you see in these blocks of generated code !
Q@e[5RA+] //}}AFX_MSG
Mcw4!{l` DECLARE_MESSAGE_MAP()
n[Zz]IO,g };
, "jbq~ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
>Sa*`q3J BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
r
_,_5
@0e BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
MyJ4><oG BOOL InitHotkey();
z|G9,:9 BOOL UnInit();
$d+DDm1o #endif
j9qREf9) f:zFFpP.j@ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
@=w<B4L #include "stdafx.h"
`=#01YX[0 #include "hook.h"
a m-b!l!q^ #include <windowsx.h>
UH@as #ifdef _DEBUG
2:}fe} #define new DEBUG_NEW
U,/6;} #undef THIS_FILE
eLwTaW !C static char THIS_FILE[] = __FILE__;
QU{Ech' #endif
r8xyd"Axy #define MAX_KEY 100
71#I5*8 #define CTRLBIT 0x04
Z'pQ^MO #define ALTBIT 0x02
gw+9x<e #define SHIFTBIT 0x01
e73^#O&Xt #pragma data_seg("shareddata")
d{et8N HHOOK hHook =NULL;
nmlPX7!{$ UINT nHookCount =0;
E{=2\Wkcp static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
O#nR>1h static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
_ 7oV< static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
k<w(i
k1bi static int KeyCount =0;
)T907I| static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
l=`L7| ^/d #pragma data_seg()
@vgG1w HINSTANCE hins;
ezhDcI_T void VerifyWindow();
[MX;,%;; BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
|(
(zTf //{{AFX_MSG_MAP(CHookApp)
[#" =yzR<3 // NOTE - the ClassWizard will add and remove mapping macros here.
*y`%]Hy< // DO NOT EDIT what you see in these blocks of generated code!
3<|`0pt} //}}AFX_MSG_MAP
/|{,sWf2 END_MESSAGE_MAP()
d
"BW/%m|g @Un/c:n CHookApp::CHookApp()
r#WT`pav {
J
)BI:]m // TODO: add construction code here,
Y9SGRV( // Place all significant initialization in InitInstance
(VyNvB }
v8>v.}y U5Erm6U: CHookApp theApp;
Ot&:mT!2 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
YF#HSf7 {
8$xPex~2 BOOL bProcessed=FALSE;
l>lW]W if(HC_ACTION==nCode)
fkfZ>D^1 {
?wMHS4 if((lParam&0xc0000000)==0xc0000000){// Key up
K*K1(_x= switch(wParam)
Vi!Q {
Xog/O i case VK_MENU:
)g|
BMmB MaskBits&=~ALTBIT;
wYeB)1. break;
h*0S$p<[1 case VK_CONTROL:
N\t1T(C| MaskBits&=~CTRLBIT;
N5|Rmfo1 break;
y;"
n9 case VK_SHIFT:
7>o.0 MaskBits&=~SHIFTBIT;
y#ON|c
/ break;
9D@$i<D: default: //judge the key and send message
PDx)S7+w[ break;
-9P2`XQ^ }
,Y_{L|:w for(int index=0;index<MAX_KEY;index++){
C>^D*C( if(hCallWnd[index]==NULL)
9z
m|Lbj continue;
m(D]qYwh if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
k0?ZYeHC {
Ue5O9;y]u SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
UIJx* bProcessed=TRUE;
t$&Qv) }
,lYaA5&I }
${~|+zdB }
Itm8b4e9; else if((lParam&0xc000ffff)==1){ //Key down
&0N<ofYX switch(wParam)
4}v@C|.p {
5`^o1nGO' case VK_MENU:
*E>.)B i MaskBits|=ALTBIT;
;sdN-mb break;
!}TMiCK case VK_CONTROL:
$<@\-vYvr@ MaskBits|=CTRLBIT;
]7sx;KFv break;
p?(L'q"WK case VK_SHIFT:
{B$2"q/~ MaskBits|=SHIFTBIT;
x!S;SU break;
Ftb%{[0}u3 default: //judge the key and send message
O/AE}] break;
xIbMs4'iEx }
k@!r#`j3 for(int index=0;index<MAX_KEY;index++)
4YG/`P {
x
FJg if(hCallWnd[index]==NULL)
F
SMj continue;
KM?1/KZ/~ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
R5Yl 1 {
/z."l!u6 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
7D" %%|:
h bProcessed=TRUE;
D _X8- }
&!.HuRiuC }
9pWy"h$H }
n/e
BE q if(!bProcessed){
8``;0}'PC for(int index=0;index<MAX_KEY;index++){
<~Qi67I if(hCallWnd[index]==NULL)
U0B2WmT~Q continue;
wjU.W5IR if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
UP1?5Q=H]Q SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
cleOsj;S }
2F_
R/{D }
?v]-^X=& }
rp!
LP#* return CallNextHookEx( hHook, nCode, wParam, lParam );
E,G<_40 }
;#?M)o:q mxTk+j= BOOL InitHotkey()
Ry;$^.7% {
Q ~|R Z7G if(hHook!=NULL){
O_@2;iD^^ nHookCount++;
T(X:Yw return TRUE;
-mNQ;zI1 }
IY(h~O else
dT@UK^\ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
4z4v\IpB if(hHook!=NULL)
o.:p_(|hI nHookCount++;
~GB=Nz return (hHook!=NULL);
85U.wpG }
_"f :` BOOL UnInit()
'E]A.3-Mt {
Ng<1Sd|MV if(nHookCount>1){
~&G4)AM nHookCount--;
g#^|oYuH6 return TRUE;
/F[+13C }
`_AM` >_ BOOL unhooked = UnhookWindowsHookEx(hHook);
0LVE@qEL if(unhooked==TRUE){
0A$SYF$O+[ nHookCount=0;
oN2=DYC41 hHook=NULL;
iSp }
CDg AGy return unhooked;
60B-ay0e$b }
rnhFqNT: Bt~s*{3$8 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
E{^^^"z P {
:xeLt; BOOL bAdded=FALSE;
*_hLD5K! for(int index=0;index<MAX_KEY;index++){
L ^Y3=1#"g if(hCallWnd[index]==0){
2wpjU&8W! hCallWnd[index]=hWnd;
a0_(eO-S HotKey[index]=cKey;
)*1.eObhL HotKeyMask[index]=cMask;
ksI>IW bAdded=TRUE;
#!#z5DJu KeyCount++;
]
pPz@@xx break;
/)#8)"`nT }
@ RR\lZ }
R9dP ,<2 return bAdded;
BA+_C]%ZJ }
L'kq>1QWf r2eQ{u{nX BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
mBl7{w;Iv {
=&U`9qN BOOL bRemoved=FALSE;
mN1Ssq"B for(int index=0;index<MAX_KEY;index++){
n.$(}A if(hCallWnd[index]==hWnd){
ijZ>:B2: if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
*Z kss hCallWnd[index]=NULL;
rY70^<z HotKey[index]=0;
vZjZb(jlN HotKeyMask[index]=0;
: }?{@#Z bRemoved=TRUE;
ZlR!s!vv KeyCount--;
Aka^e\Y@6* break;
'Ji+c }
2w1tK }
M []OHw }
>Q2). E return bRemoved;
R{3CW^1 }
it}-^3AM LpWI>sNv void VerifyWindow()
9N
Le&o {
l]5% for(int i=0;i<MAX_KEY;i++){
F$Pp]"82'm if(hCallWnd
!=NULL){ K3ukYR
if(!IsWindow(hCallWnd)){
$Ub}p[L
hCallWnd=NULL; U6{dI@|B
HotKey=0; 4;<DJ.XlN=
HotKeyMask=0; h5onRa*7
KeyCount--; pMN<p[MB
} Y6eEGo"K.+
} S<oQ}+4[~
} iHz[Zw^.s
} hx!`F
v]bAWo
BOOL CHookApp::InitInstance() f=ib9WbR#
{ TETsg5#
AFX_MANAGE_STATE(AfxGetStaticModuleState()); .hN3`>*V
hins=AfxGetInstanceHandle(); h~ha
InitHotkey(); rSyaZ6#
return CWinApp::InitInstance(); 0j@Ix EPs
} lgT?{,>RkW
Z{}+)Q*Q
int CHookApp::ExitInstance() dF,DiRD
{ i$O#%12l
VerifyWindow(); XiG88Kwv
UnInit(); &%e"9v2`
return CWinApp::ExitInstance(); )BLmoJOf
} U42\.V0
1g i}H)
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file ay[+2"
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) E^syrEz
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ L?f qcW{
#if _MSC_VER > 1000 bj.]o*u-
#pragma once V_]-`?S
#endif // _MSC_VER > 1000 oNSz&