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:
FJIo]p
Eikt, 一、实现方法
Jzj>=jWX@ R[!%d6jDE 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:
Ze3sc$fG2 $sb `BS #pragma data_seg("shareddata")
6G;t:[H G HHOOK hHook =NULL; //钩子句柄
a!mdL|eA@ UINT nHookCount =0; //挂接的程序数目
w!/|aZ~* static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
x-HR [{C static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
%!V =noo static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
T-.Bof(?w static int KeyCount =0;
jWGX:XB static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
wQrD(Dv(yA #pragma data_seg()
wyUfmk_} : G0^t 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。
FK,Jk04on dRXdV7-! 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:
;s w3MRJ 'ExTnv ~ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
ZnRE:= cKey,UCHAR cMask)
ke5_lr( {
WbHI>tt BOOL bAdded=FALSE;
4FcY NJq for(int index=0;index<MAX_KEY;index++){
Wq/0 }W. if(hCallWnd[index]==0){
2-DJ3OL]k hCallWnd[index]=hWnd;
%s#`Z [8, HotKey[index]=cKey;
M6*8}\ HotKeyMask[index]=cMask;
4/QQX;w bAdded=TRUE;
-3Auo0 KeyCount++;
y9-}LET3j
break;
Wf9K+my }
kg()C%#u
}
|&\cr\T\r return bAdded;
l1D"*J 2` }
DTM
xfQdk //删除热键
h 7*#;j BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
F1b~S;lm {
Ku;8Mx{ BOOL bRemoved=FALSE;
'Q4V(. for(int index=0;index<MAX_KEY;index++){
rtk1 8U- if(hCallWnd[index]==hWnd){
j(`V&S if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ZN-5W|' O hCallWnd[index]=NULL;
Yf[GpSej HotKey[index]=0;
~n9- HotKeyMask[index]=0;
1"
#W1im bRemoved=TRUE;
Y%YPR=j~ & KeyCount--;
1/vcj~|)t break;
e(EXQP2P> }
%( o[Hsl }
E@S5|CM }
#)28ESj return bRemoved;
0?\d%J!"S }
4e9'yi \I~9%QJ> D(^ |'1 DLL中的钩子函数如下:
vV /fTO `yWWX.` LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
I cz)Qtg| {
f*GdHUZ* BOOL bProcessed=FALSE;
>Wr if(HC_ACTION==nCode)
h&6t.2<e {
he1OLk
if((lParam&0xc0000000)==0xc0000000){// 有键松开
*Q:EICDE7 switch(wParam)
U\`H0' {
O{44GB3 case VK_MENU:
2F fwct: MaskBits&=~ALTBIT;
2a[_^v $v break;
2:D1<z6RQ case VK_CONTROL:
x2 m
A MaskBits&=~CTRLBIT;
'3V?M;3|K break;
bhc
.UmH case VK_SHIFT:
D4W^{/S MaskBits&=~SHIFTBIT;
@Z%I g break;
6$"0!fl> default: //judge the key and send message
F/zbb break;
oB] }
.~fAcc{Qj for(int index=0;index<MAX_KEY;index++){
kpt0spp if(hCallWnd[index]==NULL)
7K}Sk continue;
]U,f}T"e if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
%b(non*
{
.j_YVYu1& SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Kg MW bProcessed=TRUE;
=lqBRut }
En]+mIEo }
YQk<1./}I }
}^Kye23 else if((lParam&0xc000ffff)==1){ //有键按下
7Yrp#u1! switch(wParam)
nkvkHh {
WQT;k0;T] case VK_MENU:
fb||q-E MaskBits|=ALTBIT;
rxJWU JMxK break;
]$gBX= case VK_CONTROL:
WSPlM"h MaskBits|=CTRLBIT;
Q-LDFnOFwp break;
t/9,JG case VK_SHIFT:
]jL`*tI\S MaskBits|=SHIFTBIT;
d9n{jv| break;
(1my9k5C default: //judge the key and send message
dJ0qg_ U& break;
umD[4aP~; }
,awp)@VG7 for(int index=0;index<MAX_KEY;index++){
P6cc8x9g( if(hCallWnd[index]==NULL)
ZHku3)V=o continue;
M)oJ06`K if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
)FfJ%oT} {
H _%yh,L SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
rZBOWT bProcessed=TRUE;
w/(hEF ' }
z<rYh96uA }
ADa'(#+6 }
0Tm"Zh?B| if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
_+\hDV>v for(int index=0;index<MAX_KEY;index++){
mjd9]HgN if(hCallWnd[index]==NULL)
~!w()v n continue;
V\V:uo(C if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
LFx*_3a SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
H8}}R~ZO //lParam的意义可看MSDN中WM_KEYDOWN部分
#iot.alNA }
MFyMo }
{,|J?>{ }
u,6 'yB'u return CallNextHookEx( hHook, nCode, wParam, lParam );
lTh}0t }
?kvkdHEO_ |$vhu`]Z@^ 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:
n?QpVROo\ : Jh BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
!:[kS1s>M BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
sH>Z{xjr =v$H8w 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:
r"MKkSEM VvO/
LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
F+`DfI]/m {
;rj=hc if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
l|[8'*]r! {
o >=YoG //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
7x%0^~/n SaveBmp();
Eu AJ.n return FALSE;
?`hk0q X3 }
BW>f@;egg …… //其它处理及默认处理
L}&U%eD }
'CDRb3w}B p1=sDsLL ~lR"3z_Z} 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。
ms8PFu(f &\\iD :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。
9's/~T nD\X3g`V 二、编程步骤
1u\fLAXn b|c?xHF}K 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";
_ "ysJ& A#mf*]' 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
Kl[WscR XV2f|8d> 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;
fN8|4 6 m5 \f 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;
^Slwg|t*~P saH +C@_, 5、 添加代码,编译运行程序。
B
0%kq7>g c7jft|4S 三、程序代码
Z\E 3i T8.@}a ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
$4V ~hI4 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
H~c+L'= #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
dG|srgk+ #if _MSC_VER > 1000
!U$ %Jz #pragma once
}6P]32d #endif // _MSC_VER > 1000
/q%TjQ}F #ifndef __AFXWIN_H__
_4z>I/R>Z #error include 'stdafx.h' before including this file for PCH
K<b -|t9f #endif
GA6)O-^G #include "resource.h" // main symbols
yZ aQ{]" class CHookApp : public CWinApp
'3wte9E/ {
31 |Vb public:
I\sCH CHookApp();
[IxZweK // Overrides
#(@dN+ // ClassWizard generated virtual function overrides
j0sR]i //{{AFX_VIRTUAL(CHookApp)
voaRh@DZ%/ public:
u>(s.4]+ virtual BOOL InitInstance();
P%smX`v virtual int ExitInstance();
!+cRtCaA:: //}}AFX_VIRTUAL
ru)%0Cyx //{{AFX_MSG(CHookApp)
kTG}>I // NOTE - the ClassWizard will add and remove member functions here.
:Ke~b_$Uy- // DO NOT EDIT what you see in these blocks of generated code !
^HKxaW9W //}}AFX_MSG
uJG^>B?`b DECLARE_MESSAGE_MAP()
||7r'Q
};
Zx<s-J4o=w LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
Z{RgpVt BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
hNFMuv
BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
8|7fd|6~ BOOL InitHotkey();
VLtb16| BOOL UnInit();
J6Mm=bO5 #endif
c0Jf u=#!je //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
C,-V>bx g #include "stdafx.h"
`c{i+ #include "hook.h"
c*!bT$]~\ #include <windowsx.h>
<acAc2 #ifdef _DEBUG
z@&_3 Gl #define new DEBUG_NEW
k+-u4W #undef THIS_FILE
vVKiE 6^ static char THIS_FILE[] = __FILE__;
8Md*9E#J(" #endif
sl%B-;@I #define MAX_KEY 100
,Mc}U9)F #define CTRLBIT 0x04
hW>@jT"t1C #define ALTBIT 0x02
t,R5FoV #define SHIFTBIT 0x01
g<KBsz!{ #pragma data_seg("shareddata")
W;IvR HHOOK hHook =NULL;
Old5E& UINT nHookCount =0;
[ OMcSd|nf static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
V# w$|B\ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
?mRU9VY static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
IcPIOCmOc static int KeyCount =0;
$9*Xfb/ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
:!3CoC.X|c #pragma data_seg()
u&bo32fc HINSTANCE hins;
S! ,.#e (Y void VerifyWindow();
]=q?=%H BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
|...T
4:^Y //{{AFX_MSG_MAP(CHookApp)
e|AJxn] // NOTE - the ClassWizard will add and remove mapping macros here.
j4H,*fc // DO NOT EDIT what you see in these blocks of generated code!
)F]E[sga //}}AFX_MSG_MAP
|,t#Au}61 END_MESSAGE_MAP()
fVo)# Bj d'^jekh CHookApp::CHookApp()
:(A]Bm3 {
rN$_(%m_N // TODO: add construction code here,
$CHri| // Place all significant initialization in InitInstance
1>57rx"l }
bbiDY $}W=O:L+D CHookApp theApp;
;% !'K~ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
nd_d tsp# {
GRO[&;d` BOOL bProcessed=FALSE;
+n^$4f if(HC_ACTION==nCode)
u Dm=W36 {
&bs/a]?Z7 if((lParam&0xc0000000)==0xc0000000){// Key up
.0.Ha}{6b switch(wParam)
gGe `w {
F7# case VK_MENU:
Gnj|y?' MaskBits&=~ALTBIT;
D19uI&U4 break;
(Pc:A!} case VK_CONTROL:
#\@*C= MaskBits&=~CTRLBIT;
./[%%" break;
cRT@Cu case VK_SHIFT:
IR(JBB|xNQ MaskBits&=~SHIFTBIT;
GJ
ZT~ break;
QF'N8Kla default: //judge the key and send message
?$pp% break;
U $X"W' }
id&; for(int index=0;index<MAX_KEY;index++){
[)#,~L3 if(hCallWnd[index]==NULL)
J'b*^K continue;
7DKbuUK if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
W84JB3p {
y&-j NOKLM SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
/V2^/`&;a bProcessed=TRUE;
z~L(kf4 }
VCNg`6!x }
L!c7$M5xJ }
b!5W!vcK else if((lParam&0xc000ffff)==1){ //Key down
gI'4g ZH switch(wParam)
sR+=<u1 {
vM1f-I- case VK_MENU:
vitmG'|WG MaskBits|=ALTBIT;
,>`wz^z break;
D$I7Gz,w{ case VK_CONTROL:
V
;1$FNR
MaskBits|=CTRLBIT;
.1[K\t)2 break;
\;.\g6zX case VK_SHIFT:
DZilK: MaskBits|=SHIFTBIT;
@iS(P u break;
bh3}[O,L
A default: //judge the key and send message
x =5k74 break;
NK~j>>^;v }
m/Q@ - for(int index=0;index<MAX_KEY;index++)
3/@7$nV {
}tua0{N:z if(hCallWnd[index]==NULL)
r|{h7' continue;
1<\@i{;xsU if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Siq2Glg_ {
o(u&n3Q' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
4=%Uv^M bProcessed=TRUE;
m@u!frE, }
:0Rd )*k,v }
-*_D! }
6p1\#6#@ if(!bProcessed){
i"_)91RA for(int index=0;index<MAX_KEY;index++){
\&NpVH,- if(hCallWnd[index]==NULL)
)~rfx continue;
{W)Kz_ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
5IOOV Yl SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
+%OINMo.A }
E5~HH($b }
r1\c{5Wt }
TUw^KSa return CallNextHookEx( hHook, nCode, wParam, lParam );
ryB^$Kh,, }
X};m \Bz w4Qqo( BOOL InitHotkey()
,^pM]+NF| {
Hzcy' if(hHook!=NULL){
[ >O4hifq nHookCount++;
jrbEJ. return TRUE;
X,C&nqVFm8 }
gPSUxE`O. else
Wb+^Ue hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
"w9LQ=mW if(hHook!=NULL)
+FfT)8@W nHookCount++;
QM\vruTB return (hHook!=NULL);
}fpK{db }
,24NMv7 BOOL UnInit()
^1s!OT Is {
rbiNp6AdL if(nHookCount>1){
ZF"f.aV8) nHookCount--;
Z.am^Q^Y! return TRUE;
jJkM:iR }
{hG r`Rh BOOL unhooked = UnhookWindowsHookEx(hHook);
zpV@{%VSj if(unhooked==TRUE){
>J_{mU nHookCount=0;
3$ cDC8 hHook=NULL;
#4%4iR5% }
kMWu%,s4 return unhooked;
>!s=f }
blNE$X+0| 5L bU'5
BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
]wh8m1 {
>y m MQEX` BOOL bAdded=FALSE;
DQ :w9 for(int index=0;index<MAX_KEY;index++){
!%5ae82~3 if(hCallWnd[index]==0){
MH[Zw$ hCallWnd[index]=hWnd;
* t6XU HotKey[index]=cKey;
|7,|-s[R^ HotKeyMask[index]=cMask;
e48`cX\E bAdded=TRUE;
+(0Fab8g KeyCount++;
%lNv?sWb break;
gYVk5d|8@4 }
Zx,R6@l }
"~Twx]Z return bAdded;
`,i'vb`W#b }
Rn~FCj,- #gq4%; BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
.yE!,^j.gB {
V#.;OtF] BOOL bRemoved=FALSE;
/%C6e
)7BL for(int index=0;index<MAX_KEY;index++){
?jbE3fW if(hCallWnd[index]==hWnd){
Yr@_X if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
0JQy-hpF hCallWnd[index]=NULL;
Gc>bli<- HotKey[index]=0;
WJ=DTON HotKeyMask[index]=0;
4b=hFwr[? bRemoved=TRUE;
=Xh^@OR KeyCount--;
{[G2{ijRz break;
JW9^C }
8*kZ.-T
B }
}3:DJ(Y }
fL.;- return bRemoved;
`)e;bLP }
LO]D
XW 9 V#[I/D void VerifyWindow()
6eE%x?# {
0cZyO$. for(int i=0;i<MAX_KEY;i++){
l%\3'N] if(hCallWnd
!=NULL){ (RG\U[
if(!IsWindow(hCallWnd)){ *@o@>
hCallWnd=NULL; 0}Rxe
HotKey=0; 'Wjuv9)/
HotKeyMask=0; t+Kxww58
KeyCount--; BT;hW7){9
} _6" vPN
} Pc>$[kT0
} R 5 47
} } Uki)3(
r|4jR6%<'m
BOOL CHookApp::InitInstance() <q
hNX$t
{ E0[!jZ:c
AFX_MANAGE_STATE(AfxGetStaticModuleState()); kv&%$cA
hins=AfxGetInstanceHandle(); N
?Jr8
InitHotkey(); a(Ka2;M4J
return CWinApp::InitInstance(); -cs
4<
} B+S
&vV
5w"f.d'
int CHookApp::ExitInstance() ]\5@N7h
{ uMa: GDh7
VerifyWindow(); NCYN .@J
UnInit(); `GOxFDB.
return CWinApp::ExitInstance(); tk"L2t
} ;KJJK#j
kRs[H xI3
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file ~r;da 9
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 5MV4N[;
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ _d6mf4M]5
#if _MSC_VER > 1000 n4\6\0jq6
#pragma once R9&T0Q