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:
<_f`$z
,TJ/3_ lH 一、实现方法
^^
j/ ux&:Rw\ 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
"GLYyC O*4gV }:G #pragma data_seg("shareddata")
+3HPA#A HHOOK hHook =NULL; //钩子句柄
5U;nhDmM UINT nHookCount =0; //挂接的程序数目
1t%<5O;R static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
2*YP"Ryh static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
zP|*(* static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
?w8pLE~E static int KeyCount =0;
2mq%|VG' static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
X?kPi&ru #pragma data_seg()
neIy~H_#! c&A]pLn+x 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
h=Oh9zsz8 cUNGo%Y DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
:Lc3a$qtx5 wmiafBA e BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
^
`E@/<w8 cKey,UCHAR cMask)
Y8t
Nwh {
N[]U%9[=2F BOOL bAdded=FALSE;
!4L#$VG for(int index=0;index<MAX_KEY;index++){
Lv^a+' if(hCallWnd[index]==0){
sxt`0oE hCallWnd[index]=hWnd;
w2@"PGR HotKey[index]=cKey;
%p}qO^%M HotKeyMask[index]=cMask;
*se u& bAdded=TRUE;
jPj2 KeyCount++;
^xmZ|f- break;
B'!PJj }
<gR`)YF7 }
TXx'7[ return bAdded;
yX3PUO9 }
o;*]1 //删除热键
FE>3 D1\ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
*|@+rbjVC {
\N4d_fPj BOOL bRemoved=FALSE;
Plb}dID" for(int index=0;index<MAX_KEY;index++){
TJE%
U0Ln if(hCallWnd[index]==hWnd){
$e>/?Ss if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
kz$(V(k< hCallWnd[index]=NULL;
>@z d\}@W HotKey[index]=0;
2(hvv- HotKeyMask[index]=0;
~NA1SZ{Y+ bRemoved=TRUE;
HUK"OH KeyCount--;
R9bhC9NP break;
w<v1N }
hyM'x* }
(/('nY }
d\\r_bGW return bRemoved;
(21']x }
>7"$}5d Q %+}
,0BR-# DLL中的钩子函数如下:
poTl|y @ RfD{g"]y LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
C{8i7D {
c6f|y_2 BOOL bProcessed=FALSE;
f<'n5}{RO0 if(HC_ACTION==nCode)
@Q/x&BV {
mx:J>SPA8 if((lParam&0xc0000000)==0xc0000000){// 有键松开
R|nEd/'< switch(wParam)
@gH(/pFX {
U? {'n#n 5 case VK_MENU:
=fL6uFmxI@ MaskBits&=~ALTBIT;
v<{wA`'R+ break;
F_ ,L2J case VK_CONTROL:
J'I1,5( MaskBits&=~CTRLBIT;
R.91v4J break;
dCa}ITg case VK_SHIFT:
<WZ1- MaskBits&=~SHIFTBIT;
"PZYgl break;
x{=[w` default: //judge the key and send message
/'R UA break;
k&MlQ2'!< }
4 *Bp for(int index=0;index<MAX_KEY;index++){
+9F^F>mu if(hCallWnd[index]==NULL)
fO[Rf_ continue;
5%2ef{T[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
,k4z; {
l,imT$u SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
"z^BKb5 bProcessed=TRUE;
Z}sG3p }
+^/Nil }
VQ1?Db(_2 }
z*Myokhf else if((lParam&0xc000ffff)==1){ //有键按下
?)Tz'9l switch(wParam)
DQ}_9?3
{
7xLo4 case VK_MENU:
kA7~Yu5| MaskBits|=ALTBIT;
Hv[d<ylO break;
OVDMC4K2z! case VK_CONTROL:
&(5^vw<0 MaskBits|=CTRLBIT;
XV74Fl break;
.Ws iOJU case VK_SHIFT:
"7Toc4 MaskBits|=SHIFTBIT;
aHBByH break;
x:f|3"\s default: //judge the key and send message
L #t-KLJ break;
^
I{R[O'8 }
.fio<mqi for(int index=0;index<MAX_KEY;index++){
H]%mP| if(hCallWnd[index]==NULL)
^yn[QWFO continue;
:0J-ek.; if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Ff)~clIK ' {
'DL;c@}37 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
qB+:#Yrx/ bProcessed=TRUE;
,xAM[h& }
(5f5P84x }
USnD7I/b }
*3w/`R<\ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
.LeF|EQU\@ for(int index=0;index<MAX_KEY;index++){
"6`)vgI~ if(hCallWnd[index]==NULL)
R`I8Ud4= continue;
~aauW? if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
gTmUK{y' SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
k$UzBxR //lParam的意义可看MSDN中WM_KEYDOWN部分
=\ti< }
;qMnO_E }
/ygUd8@ }
'-nuH;r return CallNextHookEx( hHook, nCode, wParam, lParam );
zJy 89ib' }
'b=eC
"lv:hz 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
H}jK3;8E %U=S6<lbj; BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
6KIjq[T^ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
M0;t%*1 3zA8pI w 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
])$."g ^H\-3/si* LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
(IoPU+1b {
N:PA/V^z if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
% L %1g {
0bnVIG2q //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
Rktn/Vi SaveBmp();
}0Kqy; return FALSE;
6'No4[F
4n }
VtzyB …… //其它处理及默认处理
lkSz7dr@ }
DiYJlD& _Pfx_+ :~0^ib<v; 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。
cvs"WX3 <mo^Y k3 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。
) v[Knp' vS J< 二、编程步骤
x^='pEt{ G0 nH Z6 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 k1L Z_^Kl76D 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
ax{-Qi7z-+ 8x^H<y=O 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;
~Q$c!=
YP\4XI 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
g]@R'2:1 =:n[{/O= 5、 添加代码,编译运行程序。
]=86[A-2N #/B~G.+( 三、程序代码
>;' 1k' wJeqa ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
h@>rjeY@ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
9tc@
#define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
R0YC:rAt #if _MSC_VER > 1000
&PQ{e8w #pragma once
dV2b)p4J #endif // _MSC_VER > 1000
vu.S>2Wv #ifndef __AFXWIN_H__
[@. jL0> #error include 'stdafx.h' before including this file for PCH
Ng;b!S #endif
Am=PUQF$ #include "resource.h" // main symbols
YI),q.3X~ class CHookApp : public CWinApp
Kt* za {
Uhx2 _ public:
A^Hp #b@ CHookApp();
AFm*60C // Overrides
seD+~Y\z // ClassWizard generated virtual function overrides
>A'!T'"~ //{{AFX_VIRTUAL(CHookApp)
z5*O@_r+.b public:
|C2.Zay virtual BOOL InitInstance();
u,SX`6% virtual int ExitInstance();
l& ^B //}}AFX_VIRTUAL
-ZoOX"N} //{{AFX_MSG(CHookApp)
vVN[bD< // NOTE - the ClassWizard will add and remove member functions here.
+!V%Q // DO NOT EDIT what you see in these blocks of generated code !
"RJk7]p`* //}}AFX_MSG
f+*2K^B DECLARE_MESSAGE_MAP()
~{7NTW };
8^"|-~#< LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
~z1KD)^ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
eg~^wi BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
sK9h=J;F/ BOOL InitHotkey();
k&"qdB(I BOOL UnInit();
tAu|8aL #endif
UCj#t!Mw a3
_0F@I //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
nu9k{owB T #include "stdafx.h"
uy-Ncy #include "hook.h"
]jY)M<:J4 #include <windowsx.h>
y`@4n.Q #ifdef _DEBUG
NizJq*V> #define new DEBUG_NEW
WT
{Cjn #undef THIS_FILE
'nDT.i static char THIS_FILE[] = __FILE__;
|2&mvjk@H #endif
;WAu]C| #define MAX_KEY 100
Z!i'Tbfn #define CTRLBIT 0x04
<fxjj #define ALTBIT 0x02
Jsnmn$C #define SHIFTBIT 0x01
lRK?%~ #pragma data_seg("shareddata")
~t3?er& R HHOOK hHook =NULL;
:8L61d2( UINT nHookCount =0;
k'q
!MZU static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
m1;
<T@ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
o%>nu static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
4sE=WPKF# static int KeyCount =0;
8=Y|B5 static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
N)y;owgo #pragma data_seg()
)3\rp$]1 HINSTANCE hins;
XUNgt(OGR' void VerifyWindow();
vCo}-b-j BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
3:Egqw //{{AFX_MSG_MAP(CHookApp)
p;Ok.cXVp // NOTE - the ClassWizard will add and remove mapping macros here.
`l0icfy // DO NOT EDIT what you see in these blocks of generated code!
IX3yNTW"L //}}AFX_MSG_MAP
ct/THq END_MESSAGE_MAP()
s"F,=]HQ!G K{h]./% CHookApp::CHookApp()
G%/cV?18 {
pnb$lpxt // TODO: add construction code here,
/ ^M3-5@Q // Place all significant initialization in InitInstance
}33Au-%* }
JkEQ@x F+^[8zK^ CHookApp theApp;
93b5S>&r LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Qn cS& {
T js{
)r9 BOOL bProcessed=FALSE;
SygsZv&LZ if(HC_ACTION==nCode)
OU=IV;V{ {
?&^l8gE if((lParam&0xc0000000)==0xc0000000){// Key up
UM^hF% switch(wParam)
~a)20 {
$jL.TraV7 case VK_MENU:
Ase 1 R=0 MaskBits&=~ALTBIT;
goWt!,&f break;
5Z0x2jV case VK_CONTROL:
x6P^IkL: MaskBits&=~CTRLBIT;
>CA1Ub&ls break;
1x8]& case VK_SHIFT:
z`6KX93 MaskBits&=~SHIFTBIT;
2)H|/ break;
yZ6X$I:C default: //judge the key and send message
I*t}gvUt9 break;
32J }
'a9.JS[pj for(int index=0;index<MAX_KEY;index++){
'?[msX"aqa if(hCallWnd[index]==NULL)
a#@opUn- continue;
KJ
|1zCM if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
{<Zqw] {
z}|'&O*.F SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
v7RDoO]I bProcessed=TRUE;
riQ?'!a7 }
,s<d"]< }
E_#&L({|@ }
cwM0Z6
else if((lParam&0xc000ffff)==1){ //Key down
r4'Pf|`u switch(wParam)
!ym5'h {
f:>jH+o.S case VK_MENU:
QX/`s3N MaskBits|=ALTBIT;
dv:&N break;
B$n\m854 case VK_CONTROL:
$~l:l[Zs MaskBits|=CTRLBIT;
/_HL&|N_5 break;
2^:nlM{u case VK_SHIFT:
CK%W+"; MaskBits|=SHIFTBIT;
}s9J+m break;
37DvI& default: //judge the key and send message
fNumY|%3 break;
TW$^]u~v }
XPSWAp) for(int index=0;index<MAX_KEY;index++)
]y/:#^M+ {
nfEk ,(: if(hCallWnd[index]==NULL)
)eV]M~K: continue;
6{ Eh={:b if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
w;O '6" {
Uk#1PcPd SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
mv_-|N~ bProcessed=TRUE;
:/08}!_: }
(G
Y`O }
]H*=Z:riu }
hi%>&i* if(!bProcessed){
7UiU3SUcg for(int index=0;index<MAX_KEY;index++){
F$v
G=3 if(hCallWnd[index]==NULL)
] N8V?.|: continue;
y[# U/2 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
b?l\QMvi SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
G}g+2` }
pbNVj~#6 }
n/-I7Q!;u }
c|XnPqo;f return CallNextHookEx( hHook, nCode, wParam, lParam );
: s35{K }
f#?R!pR G!uxpZ BOOL InitHotkey()
BC3I{Y| {
]`x~v4JU if(hHook!=NULL){
'?nhpT^ nHookCount++;
eL*Edl|# return TRUE;
[Fe5a }
L=>N#QR7 else
*Zln\Sx hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
(,k=mF if(hHook!=NULL)
o{/D:B nHookCount++;
U -(d~]$ return (hHook!=NULL);
d+kIof, }
UCFef,VW BOOL UnInit()
dCBJV {
t_3XqjuA if(nHookCount>1){
QAr1U7{(. nHookCount--;
1*s Lj# return TRUE;
BX?Si1c
}
}Q*8QV BOOL unhooked = UnhookWindowsHookEx(hHook);
!GO4cbdQ if(unhooked==TRUE){
rd6?;K0 nHookCount=0;
Ood&cP'c hHook=NULL;
|&7l*j(\ }
:jA~zHO return unhooked;
Q%6*S!~ }
%NKf@If) m$3&r2vgi BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
i;cqK&P;] {
*5 5yF` BOOL bAdded=FALSE;
H}d&>!\}F for(int index=0;index<MAX_KEY;index++){
{ Uh/ ~zu if(hCallWnd[index]==0){
>zhbOkR9c hCallWnd[index]=hWnd;
h[Hw9$31 HotKey[index]=cKey;
<~]s+"oVc HotKeyMask[index]=cMask;
qT(j%F bAdded=TRUE;
hD"Tjd` P KeyCount++;
IRLT- break;
6j0!$q^ }
R/iXO~/"J }
+Oo>V~ return bAdded;
YS&3+Tp }
#=h~Lr'UH f>dWl$/_s BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
m)&2zV/Q {
z@dHXj ) BOOL bRemoved=FALSE;
J 5~bs*a8 for(int index=0;index<MAX_KEY;index++){
Y~,N,>nITu if(hCallWnd[index]==hWnd){
.(D-vkz' if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
2\_}81hM hCallWnd[index]=NULL;
lO[[iMHl< HotKey[index]=0;
Go8 m HotKeyMask[index]=0;
>Qr(#Bt) bRemoved=TRUE;
.:E%cL
+h KeyCount--;
@xR=bWY break;
yqZKn=1: }
ftRf~5d2 }
|-bAzt }
Y}QtgZEt return bRemoved;
aVEg%8 }
qh{hpX)\D h?jKq2`
void VerifyWindow()
R]H/Jv\' {
~0eJ6i for(int i=0;i<MAX_KEY;i++){
O1Vs! if(hCallWnd
!=NULL){ X&b)E0]pR
if(!IsWindow(hCallWnd)){ Ny\p$v
"p
hCallWnd=NULL; /3{jeU.k
HotKey=0; R^4JM,v9x`
HotKeyMask=0; eh`n?C
KeyCount--; !/2uO5
} R1)v;^B|)
} RG4T9eZq
} ^z>3+oi
} 6B'd]Fe
$DBJ"8n2
BOOL CHookApp::InitInstance() P
:zZ
{ 1ayL*tr
AFX_MANAGE_STATE(AfxGetStaticModuleState()); u 6A!Sw
hins=AfxGetInstanceHandle(); #l2KJ7AMK
InitHotkey(); YBF|0A{[Y
return CWinApp::InitInstance(); AUBZ7*VO
} WTK )SKa,.
G*` Y~SJp
int CHookApp::ExitInstance() \\}tD@V"
{ vuN!7*d+
VerifyWindow(); <u`m4w
UnInit(); U~H]w,^
return CWinApp::ExitInstance(); (@X].oM^y
} w`ebZa/j
x`9IQQ
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file xQ~}9Kt\
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) &