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:
wt8?@lJ"/
]Wc:9Zb 一、实现方法
@
m' zm: xJ2DkZ 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:
[,s{/32s [?dsS$Y3 #pragma data_seg("shareddata")
Hr?_`: HHOOK hHook =NULL; //钩子句柄
/< OoZf+[ UINT nHookCount =0; //挂接的程序数目
aP#nK static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
/(iq^ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
=)Aav! static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
+3;`4bW static int KeyCount =0;
~,*=j~#h static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
gpIq4Q< #pragma data_seg()
.u+ZrA# hkifd4# 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
+prr~vgE 3RwDIk?>% DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
V^v?;f? f
WUFCbSU BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
~9[^abz cKey,UCHAR cMask)
?+Q?K30: {
=vd9mb- BOOL bAdded=FALSE;
SFj:|S=v6j for(int index=0;index<MAX_KEY;index++){
#@quuiYq if(hCallWnd[index]==0){
<)f1skJsP hCallWnd[index]=hWnd;
-&AgjzN! HotKey[index]=cKey;
6RA4@bIG HotKeyMask[index]=cMask;
dX720/R bAdded=TRUE;
y4jJ& KeyCount++;
jrF#DDH?I break;
/h.hFM/ }
Hp#IOsP~ }
^HO'"/tB@D return bAdded;
GN&-`E]- }
~d9R:t1 //删除热键
T:~c{S4& BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
|8DMj s()* {
G_5uO58 BOOL bRemoved=FALSE;
^lI>&I&1 for(int index=0;index<MAX_KEY;index++){
X,ES=J0 if(hCallWnd[index]==hWnd){
rw9 m+q if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
:1O49g3R hCallWnd[index]=NULL;
h(<2{%j HotKey[index]=0;
u3[A~V|0= HotKeyMask[index]=0;
)BJ Z{E* bRemoved=TRUE;
X:0-FCT;\ KeyCount--;
+*'^T)sj/ break;
\&KfIh8 }
li4"|T& }
1@$n)r` }
AW6 "1(D return bRemoved;
2^V/>|W>w }
_J N$zZ{ B&bQvdp "8BZj;yS DLL中的钩子函数如下:
|qp^4vq.p SU8vz/\%y LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
wjRv=[ {
E1"H(m&6 BOOL bProcessed=FALSE;
Xb/W[rcs if(HC_ACTION==nCode)
R&!{3!V {
=
Ff 2 if((lParam&0xc0000000)==0xc0000000){// 有键松开
h#e((j3-2Z switch(wParam)
}$5e!t_K {
ZLN79r{T case VK_MENU:
gq:2`W&5 MaskBits&=~ALTBIT;
kuQ+MQHs break;
Omkpjr(1 case VK_CONTROL:
aRc2#:~; MaskBits&=~CTRLBIT;
Xy[*)< break;
,`su0P\%#. case VK_SHIFT:
Klv~#9Si MaskBits&=~SHIFTBIT;
JX $vz*KF break;
}O7!>T default: //judge the key and send message
DJ]GM|? break;
5N5Deb#V }
V1d{E 0lM for(int index=0;index<MAX_KEY;index++){
%F.^cd" if(hCallWnd[index]==NULL)
I<&(Dg|XQ continue;
#P^cR_|\ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
~HM,@5dFC {
6u6,9VG, SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
J+]W*?m bProcessed=TRUE;
W "}Cfv }
?h1r6?Sug{ }
(Y[q2b }
;_ TP Jy else if((lParam&0xc000ffff)==1){ //有键按下
vIK+18v7 switch(wParam)
7)FI_uW {
av; ~e< case VK_MENU:
8b!-2d:* MaskBits|=ALTBIT;
LOPw0@ break;
xDtJ&6uFw case VK_CONTROL:
T`Jj$Lue{ MaskBits|=CTRLBIT;
$z":E(oy break;
'|jN!y^2p case VK_SHIFT:
?Z{:[. MaskBits|=SHIFTBIT;
>'MT]@vez
break;
)LRso>iOO default: //judge the key and send message
Y`tv"v2 break;
:tTP3t5 }
aN,.pLe; for(int index=0;index<MAX_KEY;index++){
[<!4 a if(hCallWnd[index]==NULL)
XW2{I.:in> continue;
Dau'VtzN if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
kbR!iPM-; {
8
FJ>W. SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
O"c@x:i bProcessed=TRUE;
-h|YS/$f }
RY\[[eG }
d8V)eZYXy~ }
zF-M9f$_PY if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
aEJds}eE6) for(int index=0;index<MAX_KEY;index++){
nUy2)CL[L if(hCallWnd[index]==NULL)
0+P[0 continue;
e ab_"W
if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
2(%C SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Ug=)_~ //lParam的意义可看MSDN中WM_KEYDOWN部分
Xv2u7T\ }
Lfj]Y~*z }
JIYZ }
Q9C;_Up return CallNextHookEx( hHook, nCode, wParam, lParam );
O.+02C_* }
8h=Rfa9 ?yq $
>Qba 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:
YS|Ve*t(L= 7L"Pe'Hw BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
+bC=yR BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
JPt0k x]X!nx6G 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:
d7)EzW|I; PRpW*#"EI LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
8t$w/#'@ {
qE W3k), if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
to%n2^^K {
y G{;kJ P //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
!JOM+P: SaveBmp();
x[w!buV0\ return FALSE;
kNnI$(H"H }
sm1(I7y …… //其它处理及默认处理
^@a|s
Sb }
XSDudL x8v2mnk Qjl.O HO 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。
]DV=/RpJ9B Q&d"uLsx 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。
aIsT"6A~{ D)my@W0, 二、编程步骤
}X;LR\^u[f YlP8fxS 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";
:t#N.[=&# 0**.:K<i 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
\A'tV/YAd N7WQ{/PSG 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;
nYF;.k ^<"^}Jh.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;
XFx p ^ 4a6WQVS 5、 添加代码,编译运行程序。
G&?,L:^t NZh\{! 三、程序代码
PRyZ; @ &!=[.1H< ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
q%H#04Yh #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
lM N3;}K #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
b+rn:R #if _MSC_VER > 1000
6_#:LFke #pragma once
kTQvMa-X9D #endif // _MSC_VER > 1000
OU /=w pt #ifndef __AFXWIN_H__
iXJ3B&x #error include 'stdafx.h' before including this file for PCH
&qO#EEqG] #endif
O 6}eV^y #include "resource.h" // main symbols
/ivA[LSS class CHookApp : public CWinApp
Z91GM1lrf8 {
o(5eb;"yi> public:
|_ u CHookApp();
;I5u"MDHGI // Overrides
%x2_njDd // ClassWizard generated virtual function overrides
#3WKm*T/ //{{AFX_VIRTUAL(CHookApp)
F=qG+T public:
&P,z$H{o@ virtual BOOL InitInstance();
ZNX=]]HM<n virtual int ExitInstance();
G7yR&x^ //}}AFX_VIRTUAL
m[t4XK //{{AFX_MSG(CHookApp)
btV
Tt5 // NOTE - the ClassWizard will add and remove member functions here.
E#L"*vh // DO NOT EDIT what you see in these blocks of generated code !
$ZEwz;HNo //}}AFX_MSG
rCTH 5" DECLARE_MESSAGE_MAP()
l)^sE) };
~s[St0 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
/l)|B BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
pm 4"Q!K BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
`1T?\ BOOL InitHotkey();
-? |-ux BOOL UnInit();
;vDjd2@ #endif
i4XE26B;e #,4CeD|(D, //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
)8rN #include "stdafx.h"
GOII
B #include "hook.h"
)PNeJf|@ #include <windowsx.h>
X4bB #ifdef _DEBUG
0M=U>g) #define new DEBUG_NEW
`7))[._ #undef THIS_FILE
BnL [C:| static char THIS_FILE[] = __FILE__;
S.#IC
lV #endif
k-`5TmW #define MAX_KEY 100
ZI0C%c.~ #define CTRLBIT 0x04
_K#LOSMfj/ #define ALTBIT 0x02
6hvmp #define SHIFTBIT 0x01
pg4J)<t# #pragma data_seg("shareddata")
X^!1MpEQ HHOOK hHook =NULL;
0';U3:=i, UINT nHookCount =0;
I5$@1+B static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
>n^| eAH static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
;Ww s;.~ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
REe<k<>p~ static int KeyCount =0;
>Wbt_%dKy static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
l1utk8'- #pragma data_seg()
s:fy
*6=[Z HINSTANCE hins;
MBO3y&\S4 void VerifyWindow();
>kLUQ%zE@ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
Gop;!aV1* //{{AFX_MSG_MAP(CHookApp)
j=C o // NOTE - the ClassWizard will add and remove mapping macros here.
< SIe5"{ // DO NOT EDIT what you see in these blocks of generated code!
!|1GraiS //}}AFX_MSG_MAP
s?JNc4q END_MESSAGE_MAP()
n.a55uy [It
E+{U CHookApp::CHookApp()
1syI%I1 {
f'2Ufd|J| // TODO: add construction code here,
3ZF- n` // Place all significant initialization in InitInstance
=WYI|3~Cz }
Y5Ub[o c~0hu*& CHookApp theApp;
&QoV(%:] LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
~G;lEp {
\U0p?wdr: BOOL bProcessed=FALSE;
>\x if(HC_ACTION==nCode)
t5qNfiKC {
VEuT!^0Z if((lParam&0xc0000000)==0xc0000000){// Key up
6]/LrM, 23 switch(wParam)
h
dw~AGO# {
t.7KS: case VK_MENU:
Tr}
r`
% MaskBits&=~ALTBIT;
te 0a6 break;
_,U`Iq+X case VK_CONTROL:
j>?0Y MaskBits&=~CTRLBIT;
"|\G[xLOaW break;
n&`=.[+A case VK_SHIFT:
SG)hrd MaskBits&=~SHIFTBIT;
%]zaX-2dm! break;
wTL&m+xr default: //judge the key and send message
ZE!dg^-L break;
4Hk eXS. }
<yxEGjm for(int index=0;index<MAX_KEY;index++){
POl[]ni=> if(hCallWnd[index]==NULL)
$Eo)i continue;
!D_Qat if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
4]VoIUIuN {
mo$`a6[h< SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
TxN'[G bProcessed=TRUE;
lhyWlO }
~Lyy7B9 }
\R6D'Yt }
8w:A"" else if((lParam&0xc000ffff)==1){ //Key down
R43yr+p switch(wParam)
ncGg@$E {
?(up!3S'x case VK_MENU:
/]mfI&l+9 MaskBits|=ALTBIT;
4t%g:9]vr break;
g^V4+3v|a' case VK_CONTROL:
rr@S|k:| MaskBits|=CTRLBIT;
k4:e0Wd break;
'mH9O case VK_SHIFT:
)o:%Zrk MaskBits|=SHIFTBIT;
/MErS< 6 break;
&<s[(w!%% default: //judge the key and send message
x/UmpJD+ break;
F@76V$U. }
B``) for(int index=0;index<MAX_KEY;index++)
:$>Co\D {
r&u&$"c if(hCallWnd[index]==NULL)
}bW"Z2^nB continue;
tML[~AZh if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
#i8] f{ {
]
BJ] SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
~w&_l57 bProcessed=TRUE;
8:x{ }
.+;;-]}) }
?8g*"&cn }
:U,n[.$5' if(!bProcessed){
)&Bf%1> for(int index=0;index<MAX_KEY;index++){
N,iYUM? if(hCallWnd[index]==NULL)
cVx#dDdA continue;
pCE,l'Xa if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
:{(` ;fJ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
+zU[rhMk' }
0gI^GJN%Y! }
}67lL~L }
baD`k?]( return CallNextHookEx( hHook, nCode, wParam, lParam );
l(o#N'!j4 }
7)2Co[t _I"T(2Au BOOL InitHotkey()
<6
LpsM} {
Qx
B0I/
{ if(hHook!=NULL){
|wnXBKV( nHookCount++;
xJQ-k/` return TRUE;
&2~c,] 9C }
o@&Hc bN^ else
5#DtaVz hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
w?r if(hHook!=NULL)
D4@'C4kL nHookCount++;
&!@7+']) return (hHook!=NULL);
J6WyFtlyLc }
deRnP$u0 BOOL UnInit()
cZd9A(1"^ {
b,Z\{M:f;F if(nHookCount>1){
=B0#z]qu nHookCount--;
Gu3# y"a> return TRUE;
&YSjwRr
}
d".Xp4}f BOOL unhooked = UnhookWindowsHookEx(hHook);
gPo3jw o$ if(unhooked==TRUE){
=JqKdLH nHookCount=0;
7j9X<8* hHook=NULL;
2MV!@rx }
jkzC^aG return unhooked;
l7+[Zn/v * }
;;A8TcE
' 4iXB`@k BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
:`pgdn {
0[f8Gb3 BOOL bAdded=FALSE;
_a~uIGN for(int index=0;index<MAX_KEY;index++){
=i`#0i2( if(hCallWnd[index]==0){
Lrr1) h hCallWnd[index]=hWnd;
MmZs|pXk HotKey[index]=cKey;
~ AU!Gm. HotKeyMask[index]=cMask;
4axc05 bAdded=TRUE;
u?ALZxj? KeyCount++;
]*M VVzF break;
Vy-kogVt }
ySS
kw7 }
p$qpC$F return bAdded;
QR.] ?t;1 }
m(B,a,g< SR+<v=i BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
\Y>!vh X {
=;) M+" BOOL bRemoved=FALSE;
THFzC/~Q for(int index=0;index<MAX_KEY;index++){
A9?h*/$ if(hCallWnd[index]==hWnd){
J:N4F.o&K if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Q>G lA
hCallWnd[index]=NULL;
e5"?ol0 HotKey[index]=0;
"K!9^!4& HotKeyMask[index]=0;
Hq>"rrVhx bRemoved=TRUE;
FL,av>mV KeyCount--;
!6yyX}%o break;
?HsQ417.H }
]+OHxCj: }
"#3p=}] }
, :10 return bRemoved;
SEL7,8 Hm }
Z7Y+rP[l 3
zF"GT void VerifyWindow()
Q9\6Pn ]T {
-UhSy>m for(int i=0;i<MAX_KEY;i++){
a2z1/Nh if(hCallWnd
!=NULL){ W=$cQ(x4Z
if(!IsWindow(hCallWnd)){ ql+tqgo
hCallWnd=NULL; ^T{ww=/v
HotKey=0; =LUDg7P
HotKeyMask=0; U,Duq^l~s
KeyCount--; -t5DcEAb$
} Mzbbr57n
} B <CK~ybY
} ^<