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:
J24<X9b
D&KRJQ/ 一、实现方法
RuSKJ,T:9 ' ^L|}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:
.6z8fjttOC ~{lSc/SP| #pragma data_seg("shareddata")
D#R5G
HHOOK hHook =NULL; //钩子句柄
qC]6g UINT nHookCount =0; //挂接的程序数目
P0,@#M& static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
L q<# static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
Ib3n%AG static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
1S
.~Vh0Q, static int KeyCount =0;
1\K%^<QY static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
] }XsP #pragma data_seg()
y5gTd_- w ;+x g 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。
1'ts>6b +Q pgG4h 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:
n?'I&0>M 1 ~fD: BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
([\mnL<FC cKey,UCHAR cMask)
ahQdBoj {
;cKN5#7 BOOL bAdded=FALSE;
R"%zmA@o= for(int index=0;index<MAX_KEY;index++){
NH+?7rf8 if(hCallWnd[index]==0){
}n /6.% hCallWnd[index]=hWnd;
W
u?A} fH HotKey[index]=cKey;
&f48MtE HotKeyMask[index]=cMask;
[H ^ktF bAdded=TRUE;
s?r:McF` KeyCount++;
6Q\0v break;
9n\:grW }
;w0|ev6| }
;pn*|Bsq return bAdded;
t+7|/GLs2 }
IL*Ghq{/ //删除热键
.=@xTJh BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
62BT 3/~ {
&GMBvmP BOOL bRemoved=FALSE;
Mkc
for(int index=0;index<MAX_KEY;index++){
rD^ b{]E3 if(hCallWnd[index]==hWnd){
84(NylZ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
R|4a9G hCallWnd[index]=NULL;
W%Jw\ z= HotKey[index]=0;
&d}1)? HotKeyMask[index]=0;
o%Ubn* bRemoved=TRUE;
#_oN.1u57 KeyCount--;
0m8mHJ<& break;
t@=*k9 }
qaE>]) }
jUnS&1]MF }
R#QOG} return bRemoved;
(@wgNA-P }
=zaf{0c rBY)rUDd4 MPa F DLL中的钩子函数如下:
-;T!d {yj8LxX^ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
(.r9bl {
1{%3OG^' BOOL bProcessed=FALSE;
$wnK"k%G if(HC_ACTION==nCode)
LTsX{z {
EL/~c*a/ if((lParam&0xc0000000)==0xc0000000){// 有键松开
~1xfE C/ switch(wParam)
(x)}k&B; {
y^OT0mZkg case VK_MENU:
QlxzWd3=q MaskBits&=~ALTBIT;
| R\PQ/) break;
P_7QZ0k/ case VK_CONTROL:
} J_"/bB MaskBits&=~CTRLBIT;
4th*=ku break;
.5?e)o) case VK_SHIFT:
R*S9[fqC[ MaskBits&=~SHIFTBIT;
"INIP? break;
'BUix!k0< default: //judge the key and send message
(3. B\8s break;
}.ZT?p\ }
7\;4 d4u for(int index=0;index<MAX_KEY;index++){
&oJ1v<` if(hCallWnd[index]==NULL)
5f#N$mh continue;
2lb HUK if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
@la/sd4` {
8rV"? m`S SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
zeqwmV= bProcessed=TRUE;
GvB;o^Wd }
$%:=;1Jl }
V=
wWY*C }
HGiO}|q: else if((lParam&0xc000ffff)==1){ //有键按下
:r+BL@9 switch(wParam)
o54/r#~fi {
Yee%
<<S case VK_MENU:
)c6t`SBwi MaskBits|=ALTBIT;
4DwQ7KX break;
p+.xye U( case VK_CONTROL:
I-glf?F) MaskBits|=CTRLBIT;
?R!?}7 break;
A r=P;6J case VK_SHIFT:
ZBY*C;[)*P MaskBits|=SHIFTBIT;
dp|VQWCq break;
jV
'u*2&9 default: //judge the key and send message
V7S[rI<<r break;
jx=5E6(h }
gRsV-qS for(int index=0;index<MAX_KEY;index++){
t>KvR!+`g if(hCallWnd[index]==NULL)
)(/Bw&$ continue;
.`ZuUr if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
@A.7`*i_ {
G~ONHXL SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
GEs5@EH bProcessed=TRUE;
?S8_x]E }
5$PDA*]9 }
{9c_T!c }
jtH>&O if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
N{}o*K for(int index=0;index<MAX_KEY;index++){
[<nmJ-V if(hCallWnd[index]==NULL)
S Boi| continue;
0F5QAR
O if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
,5XDH6L1 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
H~1o^
gU //lParam的意义可看MSDN中WM_KEYDOWN部分
&Hj1jM' }
oF(=@UL }
j6&q6C X }
#TG7WF5 return CallNextHookEx( hHook, nCode, wParam, lParam );
L> \/%x>Wx }
kJ_XG;8 'Szk!,_ 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:
@{ CP18~: F2^qf BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
$/)0iL{0 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
KvvG
H-] (?vKe5 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:
hfL8]d- Qd"R@+i LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
^ZD0rp(l {
3?x}48 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
$5r1Si) {
V9\y*6#Y, //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
D/`b~Yl SaveBmp();
P3_&( return FALSE;
@-% .+ }
e_h`x+\: …… //其它处理及默认处理
:c3'U_H^ }
p5V.O20 [+3~wpU(p krSOS WJ 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
dXMO{*MF{H "8R\!i. 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
_08y; _S b/g~;| < 二、编程步骤
XTKAy;'5 f1wwx|b%. 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
O|e/(s?$
W*Gp0pX 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
bBp('oEJu 3f)!RKS9q 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;
, 9"A"p*R sOBuJx${m 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
JfVGs;_, 0 >:RFCo 5、 添加代码,编译运行程序。
ApotRr$) ( jtkY_ 三、程序代码
Dy|DQ> ?} @ sG5Do ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
}Zp5d7(@w #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
b l]YPx8 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
<;q)V%IUz #if _MSC_VER > 1000
gMB/ ~g5b0 #pragma once
PESJ7/^E #endif // _MSC_VER > 1000
G&\!!i|IQ #ifndef __AFXWIN_H__
qYbPF|Y=Z #error include 'stdafx.h' before including this file for PCH
I`KBj6n #endif
$[HpY)MSRw #include "resource.h" // main symbols
Q^|aix~ K class CHookApp : public CWinApp
f'& {
lFc4| _c g public:
z\6/?5D#v CHookApp();
k}908%w // Overrides
0$I!\y\ // ClassWizard generated virtual function overrides
Jh`6@d //{{AFX_VIRTUAL(CHookApp)
.{Df"e> public:
{3kI~s virtual BOOL InitInstance();
3=Va0}#& virtual int ExitInstance();
i=s>a;*# //}}AFX_VIRTUAL
JNSH'9!n6 //{{AFX_MSG(CHookApp)
1+NmiGKg // NOTE - the ClassWizard will add and remove member functions here.
F^}n7h=qk // DO NOT EDIT what you see in these blocks of generated code !
$-R9J6NN //}}AFX_MSG
z!
DD'8r> DECLARE_MESSAGE_MAP()
Xb5$ijH };
;h#nal>w@S LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
I.L8A|nZ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
}ej-Lu,b3 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
*+>R^\uT BOOL InitHotkey();
5c+7c@. BOOL UnInit();
t.]c44RY #endif
!Z`xwk"! `^1&Qz> //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Rss=ihlM #include "stdafx.h"
!#Hca #include "hook.h"
oQ_n:<3X #include <windowsx.h>
Tx0l^(n #ifdef _DEBUG
K}YOs. #define new DEBUG_NEW
; J40t14u #undef THIS_FILE
V[BlT|t static char THIS_FILE[] = __FILE__;
dD}!E #endif
#^;^_ #define MAX_KEY 100
8-
]7>2?_ #define CTRLBIT 0x04
WA 79(B #define ALTBIT 0x02
G)wIxm$?0 #define SHIFTBIT 0x01
_=oNQ #pragma data_seg("shareddata")
gKay3}w HHOOK hHook =NULL;
n:5*Tg9 UINT nHookCount =0;
zV=(e( [ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
6P:H` static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
;3k6_ub static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
G9uWn%5r static int KeyCount =0;
`Ao;xOJ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
8L}N,6gC4_ #pragma data_seg()
$N`uM HINSTANCE hins;
?FRQ!R void VerifyWindow();
`%M}
:T BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
~*Ir\wE //{{AFX_MSG_MAP(CHookApp)
.`Ts'0vVy // NOTE - the ClassWizard will add and remove mapping macros here.
h8uDs|O9n // DO NOT EDIT what you see in these blocks of generated code!
u:7=Yy
: //}}AFX_MSG_MAP
DUK.-|a7 END_MESSAGE_MAP()
;q&\>u: UZUG?UUM CHookApp::CHookApp()
.1C|J {
rO`nS<G // TODO: add construction code here,
|;B
'C# // Place all significant initialization in InitInstance
\ml6B6 }
Oz1ou[8k /+F|+1 CHookApp theApp;
F ttny] LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
4ng*SE_ {
P$|DiiH BOOL bProcessed=FALSE;
%C8fv|@:f if(HC_ACTION==nCode)
k^PqB+P! {
(B zf~#]~ if((lParam&0xc0000000)==0xc0000000){// Key up
YErn50L switch(wParam)
5bzYTK&- {
tKUy&]T case VK_MENU:
UW[{Y|oE MaskBits&=~ALTBIT;
<.<Q.z break;
e[@
^UY case VK_CONTROL:
2)^[SpZ MaskBits&=~CTRLBIT;
7" wn024 break;
!OJSQB, case VK_SHIFT:
'k9hzk(* MaskBits&=~SHIFTBIT;
;Q.g[[J/p break;
{@u}-6:wAT default: //judge the key and send message
m 5NF)eL break;
x6x6N&f? }
s!E-+Gw for(int index=0;index<MAX_KEY;index++){
^Y:Q%?uB/ if(hCallWnd[index]==NULL)
sE8.,\ continue;
pPG@_9qf if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
m&Mvb[ {
=c8U:\0 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
'#.:%4 bProcessed=TRUE;
rS
4'@a }
6YZ&>`a^ }
,b@0Qa" }
Ye}y_W else if((lParam&0xc000ffff)==1){ //Key down
n~d`PGs?f switch(wParam)
*/L;6_ {
XjwTjgL< case VK_MENU:
DOWUnJ;5 MaskBits|=ALTBIT;
`Vwj|[0k break;
wz!]]EQ!o case VK_CONTROL:
4[!&L:tR MaskBits|=CTRLBIT;
^~5tntb. break;
NoJo-vo* case VK_SHIFT:
>~$ S! MaskBits|=SHIFTBIT;
.6E7 R break;
++13m*fA default: //judge the key and send message
#U&G$E`7 break;
t@/r1u|iq }
'eo2a&S2D for(int index=0;index<MAX_KEY;index++)
*0R=(Gy {
QLH
s 3eM if(hCallWnd[index]==NULL)
ii*Ty!Sa continue;
<!zItFMD[m if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
5hp b=2 {
\Rp)n=| SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
DrltxI) bProcessed=TRUE;
C_#0Y_O }
_TB\@)\ }
m`9)DsR
N }
=I/J !}. if(!bProcessed){
ZF;S}1 for(int index=0;index<MAX_KEY;index++){
5Tpn`2F if(hCallWnd[index]==NULL)
|U^
ff^] continue;
2uWzcy ?F if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
,[bcyf SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
'EREut,>' }
h3p 3~xq }
kQIWDN }
fINM$ 6 return CallNextHookEx( hHook, nCode, wParam, lParam );
[-$&pB>w8' }
$Y,]D*|"K $vy.BYFm BOOL InitHotkey()
^B& Z {
U)p2PTfB if(hHook!=NULL){
B>Nxc@=D nHookCount++;
oT|E\wj return TRUE;
z<<` 1wqg }
1"odkM else
BJj~fNm1Zr hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
i}<R>]S if(hHook!=NULL)
SsznV}{^ nHookCount++;
nfDPM\FFD return (hHook!=NULL);
CsSB'+&{ }
#K*d:W3C BOOL UnInit()
+d6E)~qKL {
G)4 3Y! if(nHookCount>1){
v:6b&wSL3 nHookCount--;
&9s6p6eb return TRUE;
DO03vN }
2z[Pw0#V BOOL unhooked = UnhookWindowsHookEx(hHook);
o
JA58/ if(unhooked==TRUE){
Vn/6D[}Tu nHookCount=0;
&7DE$ S hHook=NULL;
Ya9uu@F }
q]Qgg return unhooked;
xJ&StN/' }
82)d.> 2|%30i,vV BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
^1cqx]>E {
Y5MHd>m BOOL bAdded=FALSE;
~hvhT}lE for(int index=0;index<MAX_KEY;index++){
:za!!^ if(hCallWnd[index]==0){
aYj3a;EmU hCallWnd[index]=hWnd;
//+UQgl6 HotKey[index]=cKey;
(`!|
Uf$ HotKeyMask[index]=cMask;
+&?VA!}. bAdded=TRUE;
sa#"@j) KeyCount++;
NOS5bm&- break;
@ ~sp:l }
6PMu;# }
y
ph return bAdded;
fRa1m?%s }
p[uwG31IL` Jx>P%>+<j BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Xj/X. {
g(5s{njL BOOL bRemoved=FALSE;
Oy|9po for(int index=0;index<MAX_KEY;index++){
e8lF$[i if(hCallWnd[index]==hWnd){
Q49|,ou[H if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
[#Yyw8V#< hCallWnd[index]=NULL;
vl*RRoJ HotKey[index]=0;
S,8zh/1y HotKeyMask[index]=0;
FD@! z
: bRemoved=TRUE;
k2@IJ~ KeyCount--;
P!O#"(r2] break;
kDv)g }
hsE!3[[ }
}]s~L9_z[' }
tRv#%>fj return bRemoved;
f(_qcgXp }
z H \*v' e.jgV=dT- void VerifyWindow()
!J71[4t {
{[9^@k for(int i=0;i<MAX_KEY;i++){
WWO jyj if(hCallWnd
!=NULL){ TRq~n7Y7C
if(!IsWindow(hCallWnd)){ !c&^b@
yw
hCallWnd=NULL; (~OwO_|3
HotKey=0; d)G-K+&B
HotKeyMask=0; U=yD!
KeyCount--; uo{QF5z]
} =az$WRV+7!
} aFSZYyPxwv
}
Fu`g)#Z
} I&xRK'
Q.|2/6hD7[
BOOL CHookApp::InitInstance() {'ZnxK'
{ |-|BM'Y
AFX_MANAGE_STATE(AfxGetStaticModuleState()); A|&EI-In
hins=AfxGetInstanceHandle(); VC+\RB#:-
InitHotkey(); _xC~44
return CWinApp::InitInstance(); -12v/an]L7
} 1=D!C lcb
lR(&Wc\j
int CHookApp::ExitInstance() 67g/(4 &
{ qQ_B[?+W
VerifyWindow(); iBi/9
UnInit(); ZV U9 t
return CWinApp::ExitInstance(); kU
Flp
} dg!sRm1iZ:
UEe qk"t^
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file bCrB'&^t
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 2<O8=I _
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ wTW"1M
#if _MSC_VER > 1000 "L)pH@)
#pragma once ;F+%{LgKl
#endif // _MSC_VER > 1000 .Sn1YAhE
5a`}DTB[Co
class CCaptureDlg : public CDialog D[r
{ btYPp0o~
// Construction <