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:
T8Sgu6:*R
48,Aq*JFw 一、实现方法
9D74/3b* ^aVoH/q*C 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:
'G z>X : %-"? #pragma data_seg("shareddata")
<}'hkEh{d= HHOOK hHook =NULL; //钩子句柄
pKK&+umg UINT nHookCount =0; //挂接的程序数目
3$f%{~3 static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
INwc@XB static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
7O5`&Z'- static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
$4.mRS97g static int KeyCount =0;
4eb<SNi static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
JtYc'%OF #pragma data_seg()
E:BEQ:(~L S!J.$Y<Ko 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。
x)<5f|j oH~ZqX.3 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:
oiAU}iK: QrDrdA BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
_@D}2 cKey,UCHAR cMask)
FxOhF03\=[ {
Bu?"b=B* BOOL bAdded=FALSE;
9R.IYnq for(int index=0;index<MAX_KEY;index++){
(?-5p; if(hCallWnd[index]==0){
wqo2iRql hCallWnd[index]=hWnd;
9/C0DDb HotKey[index]=cKey;
j}YZl@dYV HotKeyMask[index]=cMask;
@(.?e< bAdded=TRUE;
-F,o@5W>Y KeyCount++;
U,/NygB~ break;
R`=IYnoOA }
^5vFF@to }
p-V#nPb return bAdded;
)CS7>Vx }
AEkgm^t.{ //删除热键
N^|r.J BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
U@[P.y~J {
Y1AbG1n| BOOL bRemoved=FALSE;
ko!38BH`/ for(int index=0;index<MAX_KEY;index++){
qS{lay if(hCallWnd[index]==hWnd){
s%]-Sw9 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
z.23i^Q hCallWnd[index]=NULL;
}|f\'S HotKey[index]=0;
:0ND0A{K: HotKeyMask[index]=0;
jsTb0 bRemoved=TRUE;
`xe[\Z2 KeyCount--;
YlOYgr^ break;
4@#1G*OO }
k1>%wR }
a AYO(;3 }
(omdmT%D return bRemoved;
r5[om$|* }
C|"T!1MlY4 ,G1|]
~ q,d]i/T DLL中的钩子函数如下:
xt
+fuL h./cs'& LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
?zUV3Qgzj {
E=gD{1,? BOOL bProcessed=FALSE;
heZ)+}U~ if(HC_ACTION==nCode)
P&| = {
s9'g'O5 if((lParam&0xc0000000)==0xc0000000){// 有键松开
DMcvu*A switch(wParam)
xTD6?X'4 {
O60j C;{F case VK_MENU:
IgEg MaskBits&=~ALTBIT;
u]E% R& break;
@&+h3dV.V case VK_CONTROL:
jLvI!q MaskBits&=~CTRLBIT;
7|zt'.56[ break;
`]]gD EPG{ case VK_SHIFT:
[OG-ZcNu? MaskBits&=~SHIFTBIT;
aVuan&]*= break;
Cd#*Wp)s default: //judge the key and send message
?>q=Nf^ Q. break;
=Cs$0aA }
pvy;L[c for(int index=0;index<MAX_KEY;index++){
23+6u{
if(hCallWnd[index]==NULL)
mUr@w*kq|p continue;
I>/`W if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
3~I<f^K4 {
e^~t52] SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
9b]*R.x:$& bProcessed=TRUE;
SfJ/(q }
k;zbq }
2EE/xnwX }
F)e*w:D else if((lParam&0xc000ffff)==1){ //有键按下
O,qR$#l
switch(wParam)
hv*n";V {
*sJx0<!M} case VK_MENU:
F&lc8 MaskBits|=ALTBIT;
Sc Gmft3A break;
nIph[Vs-Z case VK_CONTROL:
1sc #!^Oo MaskBits|=CTRLBIT;
7u5B/M! break;
9][Mw[k> case VK_SHIFT:
c}Z,xop<P{ MaskBits|=SHIFTBIT;
1:YDN.* break;
s>~&:GUwR default: //judge the key and send message
9[T#uh!DC break;
Si]Z `_ }
4)Pt]#Ti for(int index=0;index<MAX_KEY;index++){
8SAz,m!W) if(hCallWnd[index]==NULL)
0 {{7 " continue;
]CC~Eo-%- if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
$6!` {
O-T/H-J` SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
qx0o,oZN! bProcessed=TRUE;
V<4)'UI?k9 }
fbuop&FN+q }
u6r-{[W} }
fY%Sw7ql< if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
NBMY1Xgj for(int index=0;index<MAX_KEY;index++){
p6=#LwL' if(hCallWnd[index]==NULL)
Arp4$h continue;
3pDZ}{ZZU if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
[9(B;;R@ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
L$jyeFB5 //lParam的意义可看MSDN中WM_KEYDOWN部分
;SC|VcbyH }
DvOg|XUU0 }
njUM>E,' }
{zF return CallNextHookEx( hHook, nCode, wParam, lParam );
eA4*Be;9e }
m(OBk;S~ k}T~N.0 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
jHz] gP1$#KgU BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
UO:>^,(j BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
BM&'3K_y Q ;k_q3 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:
APc@1="#J a}>GQu*y LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
J.?p?-" {
|um)vlN;9 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
vN4X%^:( {
fs)O7x-B( //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
9(X
*[X# SaveBmp();
{Z?!*Ow return FALSE;
!h4 So4p }
$(CHwG- …… //其它处理及默认处理
=u;q98r }
sJM}p5V IBF>4qm" UT{Nly8u 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。
pwZ &2&| `HJw wKd 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。
A1'IK.
@ics 二、编程步骤
I"
j7 =)I{KT: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";
O/-OW: 03 @K+u+}
R 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
rW6w1 *v5y]E%aW 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;
a9qZI 'Gt`3qG 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;
=G72`]#- cxv)LOl- 5、 添加代码,编译运行程序。
pEaH^(I* }oU&J81 三、程序代码
~~fL`" WYzY#-j ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
e4`KnHsL #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
Xs?>6i@$$ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
rU~"A #if _MSC_VER > 1000
GYs4#40 #pragma once
jyT(LDsS #endif // _MSC_VER > 1000
VI+Y 4T@ #ifndef __AFXWIN_H__
EwOTG
Y{0p #error include 'stdafx.h' before including this file for PCH
{MEU|9@
Y #endif
d[Fsp7U} #include "resource.h" // main symbols
'V>+G>U class CHookApp : public CWinApp
d
z\b]H] {
2'}2r ~6 public:
=VSieh CHookApp();
{Y/ // Overrides
02+^rqIx5 // ClassWizard generated virtual function overrides
r-0
7!A //{{AFX_VIRTUAL(CHookApp)
1%:A9%O)t public:
Ud9\;Qse virtual BOOL InitInstance();
]E3g8?L virtual int ExitInstance();
AP~!YwLW //}}AFX_VIRTUAL
pKJ[e@E^ //{{AFX_MSG(CHookApp)
SwL\=nq+~ // NOTE - the ClassWizard will add and remove member functions here.
(J;?eeP // DO NOT EDIT what you see in these blocks of generated code !
50Jr(OeU< //}}AFX_MSG
ujSzm=_P DECLARE_MESSAGE_MAP()
Bh.'%[', };
'qD9kJ` LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
He@= bLLa BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
*K 7L5. BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
(l^lS=x BOOL InitHotkey();
:Oj+Tc9A BOOL UnInit();
<;T7qEIlo #endif
@kK=|(OB' s1FBz)yCY= //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
D|BN_ai9 #include "stdafx.h"
PDsLJ|:yL #include "hook.h"
N1-LM9S #include <windowsx.h>
Ay`a>:p #ifdef _DEBUG
<wA_2S
Y #define new DEBUG_NEW
d^Wh-U #undef THIS_FILE
bpILiC static char THIS_FILE[] = __FILE__;
N?Z?g_a8 #endif
%2+]3h>g #define MAX_KEY 100
@rF\6I #define CTRLBIT 0x04
u`~{:V #define ALTBIT 0x02
pJ(l=a #define SHIFTBIT 0x01
`fRy"44nR #pragma data_seg("shareddata")
Ue7W&N^E HHOOK hHook =NULL;
g\Zk*5( UINT nHookCount =0;
aD^MoB3 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
g:)vthOs static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
+Oscy-; static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
1W8W/Y=hT static int KeyCount =0;
:Ry24X static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
%qHT!aP #pragma data_seg()
= V , _ HINSTANCE hins;
,ym;2hJ void VerifyWindow();
!L_ SHlU BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
{MtB!x //{{AFX_MSG_MAP(CHookApp)
`iI"rlc // NOTE - the ClassWizard will add and remove mapping macros here.
buFtLPe // DO NOT EDIT what you see in these blocks of generated code!
/%c^ i!=f" //}}AFX_MSG_MAP
+NY4j-O END_MESSAGE_MAP()
`3KprpE8v L_r &'B CHookApp::CHookApp()
CvJm7c {
N'1~ wxd // TODO: add construction code here,
:&%;s*-9 // Place all significant initialization in InitInstance
#Q"vwek }
Hn~1x'$ 6b|`[t CHookApp theApp;
ChGM7uu2 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
gK( 4<PO' {
""d>f4,S BOOL bProcessed=FALSE;
|gz,Ip{ if(HC_ACTION==nCode)
o~K 2K5I {
$yAfs3/%)s if((lParam&0xc0000000)==0xc0000000){// Key up
QFPx4F7(e switch(wParam)
8hfh,v5( {
-Tx tX8v case VK_MENU:
Mvv=)?: MaskBits&=~ALTBIT;
%np#Bv-L break;
"Zk6B"o) case VK_CONTROL:
av?BpN"l MaskBits&=~CTRLBIT;
a:}"\>Aj break;
)'~FDw\6 case VK_SHIFT:
~'MWtDe:Z8 MaskBits&=~SHIFTBIT;
.B13)$C break;
G#:!wI default: //judge the key and send message
r\d:fot break;
clw91yrQn }
'qJ-eQ7e for(int index=0;index<MAX_KEY;index++){
^Q>*f/.KN if(hCallWnd[index]==NULL)
JWL J<z continue;
-/%jeDKp if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Jf$wBPg {
o}A #- SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
ea0tx3' bProcessed=TRUE;
HqBPY[;s }
>G2-kL_ }
D3xaR }
CE,Om^ else if((lParam&0xc000ffff)==1){ //Key down
@U{M"1zZe switch(wParam)
#:|?t&On {
JZzf,G: case VK_MENU:
RH Vv}N0 MaskBits|=ALTBIT;
'.yWL break;
&|'6-wD. case VK_CONTROL:
|sa7Y_ MaskBits|=CTRLBIT;
@3 c#\jx break;
,d>~=' case VK_SHIFT:
U_'q- *W MaskBits|=SHIFTBIT;
AFTed?( break;
"}p?pF<'0 default: //judge the key and send message
--`LP[ll break;
#\BI-zt }
o(/ia3 for(int index=0;index<MAX_KEY;index++)
?w/nZQWi {
.~L4#V{c~ if(hCallWnd[index]==NULL)
zI! R-Nb continue;
F |81i$R if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
+c`C9RXk {
~4MjJKzA SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
m1i+{(( bProcessed=TRUE;
yQ{_\t1Wd }
[9om"' }
P&0cF{ }
lhl0 if(!bProcessed){
JK"uj% for(int index=0;index<MAX_KEY;index++){
.oj" ru if(hCallWnd[index]==NULL)
43=-pyp continue;
sDm},=X} if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
y%bqeo
L~ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
b^DV9mO4J }
8'"/gC{ }
}#>d2 =T$ }
n "KJB return CallNextHookEx( hHook, nCode, wParam, lParam );
_np>({ }
FR^wDm$ h_G|.7! BOOL InitHotkey()
9~'Ip7X,! {
!9 LAXM if(hHook!=NULL){
Y~hd<8 ~ nHookCount++;
?>jArzI return TRUE;
H0 n@kKr }
W?J*9XQ` else
ioa_AG6B hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
<VR&=YJ if(hHook!=NULL)
G!LNP&~ nHookCount++;
j_uY8c>3\q return (hHook!=NULL);
*2
$m>N }
e=)*O BOOL UnInit()
ZX6=D>)u {
_AHB|P I if(nHookCount>1){
il cy/ nHookCount--;
Ox*T:5 return TRUE;
40d9/$uzh }
B
m@oB2x) BOOL unhooked = UnhookWindowsHookEx(hHook);
TgE.=` "7 if(unhooked==TRUE){
f9XO9N,hE: nHookCount=0;
>wk=`&+V@ hHook=NULL;
b;`#Sea }
gc:p@< return unhooked;
Y1_6\zpA }
lPQ
Ut!xI \]#;!6ge BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
.y_bV= {
\3(|c#c BOOL bAdded=FALSE;
d>b,aj( for(int index=0;index<MAX_KEY;index++){
NT9- j#V if(hCallWnd[index]==0){
!na0 Y hCallWnd[index]=hWnd;
hOL y*% HotKey[index]=cKey;
2X;0z$ HotKeyMask[index]=cMask;
y#Za|nt bAdded=TRUE;
JS7}K)A2B6 KeyCount++;
($ B]9* break;
K6yFpVl }
h-+a;![ }
-KJ! return bAdded;
OK2/k_jXN' }
9EA
!j} 8j+:s\ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
\
[^)
WQ {
]V769B9 BOOL bRemoved=FALSE;
{9|$%4kRl for(int index=0;index<MAX_KEY;index++){
qTa]th; if(hCallWnd[index]==hWnd){
ny_ kr`$42 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
]7R&m)16 hCallWnd[index]=NULL;
nK%/tdq HotKey[index]=0;
n.Eoi4jV' HotKeyMask[index]=0;
vb. Y8[ bRemoved=TRUE;
Gp3nR<+ KeyCount--;
"tz0ko,( break;
p5# P
r }
Q~Sv2 }
sHPwW5j/o' }
0jJ28.kOp return bRemoved;
zTBi{KrZ }
"G-0i KW; 60~>f)vu void VerifyWindow()
b^l
-*4 {
;$tv8%_L[ for(int i=0;i<MAX_KEY;i++){
A]O5+"mc if(hCallWnd
!=NULL){ Yx}"> ;\
if(!IsWindow(hCallWnd)){ ?(NT!es
hCallWnd=NULL; 5IE+M
HotKey=0; uM#U!
HotKeyMask=0; >gZk
581/
KeyCount--; gC_s\WU
} 6(q`Oj
} o|^?IQ7bpf
} 5)>ZO)F&
} qnk,E-
7ru9dg1?
BOOL CHookApp::InitInstance() wp]7Lx?F
{ D_19sN@0m
AFX_MANAGE_STATE(AfxGetStaticModuleState()); N} x/&e
hins=AfxGetInstanceHandle(); kG;eOp16R
InitHotkey(); j#nO6\&o
return CWinApp::InitInstance(); 8T.5Mhx0jS
} #SihedWi
1l|A[G
int CHookApp::ExitInstance() U ygw*+
{ w(e+o.:
VerifyWindow(); 2) /k`Na
UnInit(); .iP G /e
return CWinApp::ExitInstance(); %X9:R'~ sP
} MNf @HG
ofPF}
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file hDD~,/yVxs
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) +%le/Pg@
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ TH(Lzrbg
#if _MSC_VER > 1000 Ky'3z"
#pragma once THbtu*El
#endif // _MSC_VER > 1000 32bkouq
]g8i>,G
class CCaptureDlg : public CDialog :9x084ESR)
{ FG;<`4mY
// Construction ]2xx+P#Y
public: @cS1w'=
BOOL bTray; sx-Hw4.a"
BOOL bRegistered; XEUa
BOOL RegisterHotkey(); z"s%#/#
UCHAR cKey; 7S dV%"
UCHAR cMask; vzohq1r5
void DeleteIcon(); &`
00/p
void AddIcon(); =_?pOq
UINT nCount; |B1;l<|`
void SaveBmp(); FQ_%)Ty2
CCaptureDlg(CWnd* pParent = NULL); // standard constructor O'!r]0Q
// Dialog Data "3Xv%U9@
//{{AFX_DATA(CCaptureDlg) <