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:
-IbbPuRq
I=o'+>az 一、实现方法
jx'2N~$ V'C-'Ythwf 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:
QE3ryD HZ{n&iJ #pragma data_seg("shareddata")
,2ME2@OP HHOOK hHook =NULL; //钩子句柄
H@Q` UINT nHookCount =0; //挂接的程序数目
puA|NT static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
![).zi+m static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
+O4( a. static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
ZJ9x6|q static int KeyCount =0;
7pP+5&* static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
95[wM6?J #pragma data_seg()
D,E$_0 y~dB5/ 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。
=tn Tdp0F 9{$8\E9*nd DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
F(;jM( Fh^ox"3c BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
:pb67Al29 cKey,UCHAR cMask)
;$z7[+M {
3T?f5+@I BOOL bAdded=FALSE;
'u1=XX
h for(int index=0;index<MAX_KEY;index++){
+v!v[qn if(hCallWnd[index]==0){
Hsgy'X%om hCallWnd[index]=hWnd;
KxX[S.C HotKey[index]=cKey;
!VFem~'d HotKeyMask[index]=cMask;
^EuW(
" bAdded=TRUE;
d+Ds9(gV KeyCount++;
qF'~F`6 break;
4~*Y];!Q }
Gnk|^i;t }
Co[n--@C return bAdded;
Tt%}4{"
}
-,|ha>r //删除热键
-Uri|^t BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
7=vYO|a/4 {
W_%W%i| BOOL bRemoved=FALSE;
Qm; BUG] for(int index=0;index<MAX_KEY;index++){
S+iP^*L,c if(hCallWnd[index]==hWnd){
$o"g73`3 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
<}]{~y hCallWnd[index]=NULL;
C38%H HotKey[index]=0;
iE=P'"I HotKeyMask[index]=0;
ewym1}o bRemoved=TRUE;
|by@ :@*y KeyCount--;
/p 5=i break;
^aHh{BQ% }
M%|f+u & }
ikIzhUWE }
!LiQ 1`V{ return bRemoved;
<wa(xDBw }
gB >pd?d YmgCl!r@ ;iQp7aW{$ DLL中的钩子函数如下:
9x[ U$B +6oG@ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
jq[x DwPG {
{>h97}P BOOL bProcessed=FALSE;
B4^`Sw if(HC_ACTION==nCode)
c.0]1 {
F"[3c6yF if((lParam&0xc0000000)==0xc0000000){// 有键松开
kW+G1| switch(wParam)
).Gd1pE {
?@DNsVwb case VK_MENU:
nj MaskBits&=~ALTBIT;
E(;i> break;
??(Kwtx{ case VK_CONTROL:
qv uxhz F MaskBits&=~CTRLBIT;
'?8Tx&}U8 break;
# 66e@ case VK_SHIFT:
2( _=SfQ MaskBits&=~SHIFTBIT;
-njQc:4W,- break;
YZ**;"<G default: //judge the key and send message
u7#z^r break;
)
$#(ZL^m }
N Bz%(?\ for(int index=0;index<MAX_KEY;index++){
GI_DhU]~) if(hCallWnd[index]==NULL)
Pin/qp&Fa8 continue;
"{ FoA3g| if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
0;<OYbm3< {
cgN>3cE SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
auL^%M|$R bProcessed=TRUE;
aq kix"J }
e9:P9Di(b }
[e1L{ _*l
}
/>F.Nsujy else if((lParam&0xc000ffff)==1){ //有键按下
02pplDFsM switch(wParam)
hfv%,,e {
/WYh[XKe case VK_MENU:
t%$@fjz MaskBits|=ALTBIT;
1a8$f5 break;
8(Fu case VK_CONTROL:
f'_M0x MaskBits|=CTRLBIT;
\igaQ\~ break;
oCuV9dA. case VK_SHIFT:
`pm>' MaskBits|=SHIFTBIT;
;RHNRVP break;
:1MMa6 default: //judge the key and send message
hDvpOIUL1 break;
GO~k ' }
gl
"_:atW for(int index=0;index<MAX_KEY;index++){
y
1nU{Sc@ if(hCallWnd[index]==NULL)
#KE;=$(S continue;
y<*-tZV[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
%Rarr {
l"5y?jT SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
o_rtH|ntX5 bProcessed=TRUE;
6p m~sD }
j|(:I: ] }
9^\hmpP@D }
N"1QX6 if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
W_}/ O'l{ for(int index=0;index<MAX_KEY;index++){
'\t7jQ if(hCallWnd[index]==NULL)
gQ+9xT d continue;
]nc2/S% if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
t7^D-l SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
KTv4< c] //lParam的意义可看MSDN中WM_KEYDOWN部分
s#P:6]Ar }
u E.^w;~2= }
_Wma\(3$ }
k FLT!k return CallNextHookEx( hHook, nCode, wParam, lParam );
k{-`]qiK }
}"4roJ s5AgsMq 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:
iC*U $+JG O^NP0E BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
Mpm#GdT BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
^*>n4U .eY`Ri<3t 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
I4~^TrznRa u>o<tw%Y LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
zt?H~0$LB {
#HG&[Ywi if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
W>$BF[x!{ {
[pR)@$"k' //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
G#lg|# -# SaveBmp();
[+Un ^gD return FALSE;
[%~^kq=| }
u`6/I#q` …… //其它处理及默认处理
>BJ}U_ck }
|D<+X^0' GoD ?K C 4E'|.tt( 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。
"K
?#,_ \ 3G*j` 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。
X:{WZs"[x ev"M;"y 二、编程步骤
r=$gT@ WIG=D{\Yx 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";
O<`,,^4w/ -l JYr/MSL 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
<jFSj=cIL k*Pz&8| 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(!<Ux_ 5~[N/Gl 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;
~6sE an3p H%C\Uz"o 5、 添加代码,编译运行程序。
yQwVQUW8B V{GXc:= 三、程序代码
rhoeZ HamEIL-l. ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
4#h?Wga #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
;
8E; #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
G_+Ph^ #if _MSC_VER > 1000
:'Xr/| s #pragma once
S.hC$0vrj #endif // _MSC_VER > 1000
<m1sSghg #ifndef __AFXWIN_H__
7}o6_i #error include 'stdafx.h' before including this file for PCH
:l`i4kx #endif
!qaDn.9 #include "resource.h" // main symbols
{+\'bIV[ class CHookApp : public CWinApp
n1?}Xq| {
}P.K2ku public:
LU(%K{9 CHookApp();
M')bHB(~v // Overrides
u<kD} // ClassWizard generated virtual function overrides
9v$qrM`8 //{{AFX_VIRTUAL(CHookApp)
>2Ca5C public:
s|gp virtual BOOL InitInstance();
|z+9km7, virtual int ExitInstance();
A6i
et~h[ //}}AFX_VIRTUAL
IfB/O.;Kz //{{AFX_MSG(CHookApp)
*]2R.u // NOTE - the ClassWizard will add and remove member functions here.
%A2`&:ip // DO NOT EDIT what you see in these blocks of generated code !
n}:t< //}}AFX_MSG
AsAFUuI DECLARE_MESSAGE_MAP()
n.Vtc-yZU };
u}m.}Mws LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
:MBS>owR BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
J 8q BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
y1u9B;Fd BOOL InitHotkey();
?@3&dk~ni BOOL UnInit();
Yw[{beo #endif
"uhV|Lk*7 5 H *> //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
h~fWE #include "stdafx.h"
uP Rl[tS0 #include "hook.h"
/n8psj #include <windowsx.h>
x ;mJvfX #ifdef _DEBUG
]?&H^"= #define new DEBUG_NEW
QP V@'.2m #undef THIS_FILE
"Y(^F
bs static char THIS_FILE[] = __FILE__;
RM#fX^)= #endif
zLK\I~rU! #define MAX_KEY 100
3G.r- #define CTRLBIT 0x04
avy=0Jmj #define ALTBIT 0x02
#B}Qt5w #define SHIFTBIT 0x01
Jh^8xI,`C #pragma data_seg("shareddata")
0T0/fg(o HHOOK hHook =NULL;
WvbEh|y UINT nHookCount =0;
)7w@E$l" static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
FT4l$g7" static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
ctK65h{Eo static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
)2]a8JVf static int KeyCount =0;
obYn&\6 static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
yl]UUBcQ #pragma data_seg()
]< +3Vw HINSTANCE hins;
e2bLkb3c void VerifyWindow();
%ZuLl( BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
yp?w3|`4; //{{AFX_MSG_MAP(CHookApp)
hv{87`L'K( // NOTE - the ClassWizard will add and remove mapping macros here.
9#fp_G;= // DO NOT EDIT what you see in these blocks of generated code!
[,GU5,o //}}AFX_MSG_MAP
?$16A+ END_MESSAGE_MAP()
`[bJYZBc2 c"qPTjY CHookApp::CHookApp()
w49{-Pp[ {
%Gu][_.L // TODO: add construction code here,
f,JX" // Place all significant initialization in InitInstance
{( dP }
.OV-`TNWj Y-= /,
CHookApp theApp;
-~}
tq] LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
D>Ua#<52q {
dEG ]riO BOOL bProcessed=FALSE;
Fn> <q: if(HC_ACTION==nCode)
Uh%6LPg^ {
b@!:=_Mr if((lParam&0xc0000000)==0xc0000000){// Key up
fzyzuS$ switch(wParam)
EU9[F b] {
)6 k1 P case VK_MENU:
u6pIdt MaskBits&=~ALTBIT;
N2% :h;tf break;
?y46o2b*) case VK_CONTROL:
ZBC@xM&- MaskBits&=~CTRLBIT;
/L$NE$D} " break;
r*]uR /Z$ case VK_SHIFT:
s{B_N/^ MaskBits&=~SHIFTBIT;
Wxc^_iqA1 break;
h&P
{p _Y default: //judge the key and send message
Zsgi{ break;
#?Wo <]i }
1EuK,:x for(int index=0;index<MAX_KEY;index++){
"5h_8k~sQ if(hCallWnd[index]==NULL)
@ce3%`c_ continue;
Y6a$gXRT if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
lU&Q^Zj` {
El+Ft.7 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
mQL8QW[c bProcessed=TRUE;
s6IP;} }
5)8. }
0NrTJ R` }
&<@%{h@= else if((lParam&0xc000ffff)==1){ //Key down
smbUu/ switch(wParam)
k0knPDbHv {
t%:G|n Sz case VK_MENU:
#.b^E3#+ MaskBits|=ALTBIT;
>R#9\/s break;
Stt* 1gT case VK_CONTROL:
MorW\7-} MaskBits|=CTRLBIT;
}`#Bf break;
t+J)dr case VK_SHIFT:
YY\Rua/nG MaskBits|=SHIFTBIT;
I0(8Z]x break;
v/x*]c!"` default: //judge the key and send message
zaBG= break;
^ISQ{M#_ }
$M-NR||k for(int index=0;index<MAX_KEY;index++)
Z<I[vp6{ {
j $KM9 if(hCallWnd[index]==NULL)
"s${!A) continue;
p#z;cjfSt if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
r.9 $y/5 {
8>m1UO Nr SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
dw3'T4TC? bProcessed=TRUE;
\3M1.Q4$Gr }
D?%e"*> }
~%/'0}F }
LK{a9`
h if(!bProcessed){
98=XG1sQ@ for(int index=0;index<MAX_KEY;index++){
5"[yFmP* if(hCallWnd[index]==NULL)
Iht@mE continue;
FGDw;lEa9[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
BJ"Ay@D* SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
;*_I,|A:Xr }
9wzg{4/-$ }
wqf& i^_ }
tG_-;03<`4 return CallNextHookEx( hHook, nCode, wParam, lParam );
FRc |D }
y.
Tct. aK!xRnY BOOL InitHotkey()
+B](5 z4 {
"\}21B~{7' if(hHook!=NULL){
jzQ9zy_ nHookCount++;
^971<B(v return TRUE;
cK/PQsMP }
G;Us-IRZ else
1O|RIv7F[/ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
O.dux5lfBd if(hHook!=NULL)
|b,zw^!e[' nHookCount++;
L,GShl 0S return (hHook!=NULL);
C CLfvex }
jt/l,=9YK BOOL UnInit()
#DrZ`Aq {
WT I 'O if(nHookCount>1){
s8{-c^G:R nHookCount--;
on6<l return TRUE;
>c&4_?d&,A }
J6= w:c BOOL unhooked = UnhookWindowsHookEx(hHook);
1k*n1t): if(unhooked==TRUE){
]j72P nHookCount=0;
,.J<.#D3J hHook=NULL;
R%qX_m\0 }
|:dCVd<du return unhooked;
\YjB+[. }
3x,Aczb FfZ{%E BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
XryQ)x( {
@"jmI&hYn BOOL bAdded=FALSE;
5?D1][ for(int index=0;index<MAX_KEY;index++){
q#l.A?rK\ if(hCallWnd[index]==0){
=ZFcxGo hCallWnd[index]=hWnd;
X+/{%P!w HotKey[index]=cKey;
Jii?r*"d HotKeyMask[index]=cMask;
-WQ_[t9l bAdded=TRUE;
ScM}m KeyCount++;
O_qu;Dx! break;
sj#{TTW }
~+7a d$ }
+#^sy> return bAdded;
rE!G,^_{ }
Y'3kE 0G~%UYB- BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
h9,wiT {
l2z`<2mp BOOL bRemoved=FALSE;
/e;e\k_}' for(int index=0;index<MAX_KEY;index++){
}G"r3*
if(hCallWnd[index]==hWnd){
Q>cL?ie if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Xi 1q]ps hCallWnd[index]=NULL;
50}.Xm@,BO HotKey[index]=0;
bjU 2UcI"< HotKeyMask[index]=0;
!&1}w86 bRemoved=TRUE;
a15,'v$O KeyCount--;
B]&Lh~Im break;
fhVbJU }
>OF:"_fh }
wghFGHgw }
NN31?wt return bRemoved;
Dwm@E\^ihm }
WO.}DUfG+ 'YBLU )v[ void VerifyWindow()
Lf$Q
%eM0 {
N]3-L`t for(int i=0;i<MAX_KEY;i++){
o06A=4I if(hCallWnd
!=NULL){ 'vqj5YTj
if(!IsWindow(hCallWnd)){ Qi(e`(,'
hCallWnd=NULL; /1[}G!
HotKey=0; @5<]W+jk4
HotKeyMask=0; e'}ePvN
KeyCount--; D2hAlV)i(
} P_:?}h\
} V{7lltu
} 5n&)q=jk=
} ==PQ-Ia
V{ 4i$'
BOOL CHookApp::InitInstance() 9Bbm7Gd
{ S,d ngb{
AFX_MANAGE_STATE(AfxGetStaticModuleState()); E.5*Jr=J
hins=AfxGetInstanceHandle(); !#cKF6%
InitHotkey(); 4OqE.LFu
return CWinApp::InitInstance(); a PcGI
} uFA|rX
*il]$i
int CHookApp::ExitInstance() 0ECO/EuCg
{ n $D}0wSM/
VerifyWindow(); XL"v21X
UnInit(); es*_Oo1
return CWinApp::ExitInstance(); sWojQ-8}
} Wo1V$[`Dy
F3H:I"4
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file _oMs
`"4K
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 5JXzfc9rL
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ u"Hd55"&
#if _MSC_VER > 1000 <