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:
IWu^a w
!s,<hU# 一、实现方法
lp[3z&u ub6\m=Y7 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:
($(6]?J(?7 T(+F6d=1 #pragma data_seg("shareddata")
V5rnI\:7 HHOOK hHook =NULL; //钩子句柄
^7q=E@[e UINT nHookCount =0; //挂接的程序数目
!mBsDn(J static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
n ! qm static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
$N;!. 5lX3 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
Lhl)p P17 static int KeyCount =0;
a#H=dIj static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
Ary$,3X2 #pragma data_seg()
oT
8
Td[w<m+p<P 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。
r0G#BPgdR 0 w\X 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:
DjOFfD\MF B0=:A BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
mDE{s",q/ cKey,UCHAR cMask)
pALB[;9g {
)xQxc. BOOL bAdded=FALSE;
0vG}c5;F for(int index=0;index<MAX_KEY;index++){
{+c/$4< if(hCallWnd[index]==0){
)$q<"t\#P# hCallWnd[index]=hWnd;
1E$Z]5C9 HotKey[index]=cKey;
xy mK| HotKeyMask[index]=cMask;
q^sMJ bAdded=TRUE;
`Q26Dk KeyCount++;
N(Y9FD;H break;
~p;<H }
{EJVZG:& }
*B}vYX return bAdded;
:'y }
|UnTd$m //删除热键
N)Qj^bD! BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
,b>cy&ut {
e"r'z
n BOOL bRemoved=FALSE;
UQ|0Aqwq for(int index=0;index<MAX_KEY;index++){
M0Z>$Az]t if(hCallWnd[index]==hWnd){
_WK+BxH if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
QZ{&7mc> hCallWnd[index]=NULL;
NJqALm!( HotKey[index]=0;
(m;P,* HotKeyMask[index]=0;
#!#V!^ o bRemoved=TRUE;
d\;M F KeyCount--;
dMGu9k~u break;
3\=8tg p }
ZfT%EPoZ: }
-Qnnzp$] }
nWFp$tJ/R return bRemoved;
^'EEry }
:^%soEi I-/PzL<W P y=h2_jt DLL中的钩子函数如下:
vCH>Fj"7 ^e@c
Ozt LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
gEKJrAA {
}/c.>U BOOL bProcessed=FALSE;
P05_\
t if(HC_ACTION==nCode)
sbK0OA {
bDUGzezP< if((lParam&0xc0000000)==0xc0000000){// 有键松开
DP^{T/G switch(wParam)
a]X6) 6 {
mf}?z21vD case VK_MENU:
m.K"IXD MaskBits&=~ALTBIT;
)Xd=EWGUS break;
!YJdi~q
case VK_CONTROL:
e}[$ = MaskBits&=~CTRLBIT;
Br#]FB|tD break;
*qOo,e case VK_SHIFT:
aF'Ik XG d MaskBits&=~SHIFTBIT;
}$qy_Esl break;
Ce 5
}+A} default: //judge the key and send message
)>\Ne~% break;
A1Q]KS@ }
$Fr2oSTT) for(int index=0;index<MAX_KEY;index++){
R63"j\0 if(hCallWnd[index]==NULL)
;uoH+`pf continue;
FNc[2sI if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
4D58cR} {
@.0jC=!l SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
gEi"m5po bProcessed=TRUE;
&7@6Y{!/
}
?R,^prW{ }
d=>5%$:v }
$ ~D`-+J else if((lParam&0xc000ffff)==1){ //有键按下
1GEE ^Eu switch(wParam)
=,T~F3pK {
t4gD*j6J3 case VK_MENU:
#mllVQ MaskBits|=ALTBIT;
Opjt? ] break;
R4IFl
z case VK_CONTROL:
G uDus2#+ MaskBits|=CTRLBIT;
~7~nU>Vv break;
0A1l"$_| case VK_SHIFT:
.7)A8R7Wt MaskBits|=SHIFTBIT;
@F,HyCSN break;
p^L6uM default: //judge the key and send message
q1?2
U< break;
2iH,U }
(j-(fS for(int index=0;index<MAX_KEY;index++){
&UzZE17R if(hCallWnd[index]==NULL)
"%.#/!RG continue;
-TD6s:' if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
CiMy_`H {
!o.g2 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
dUe"qH29s bProcessed=TRUE;
$iP#8La:Y }
jM7}LV1Ck }
C&5T;=<jKO }
2<988F if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
@x=CMF15 for(int index=0;index<MAX_KEY;index++){
ikxSWO_Y= if(hCallWnd[index]==NULL)
u@gYEx} continue;
\DQ; v if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
xE)pj| SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
_X]? //lParam的意义可看MSDN中WM_KEYDOWN部分
?v")Z0 ~ }
r},|kb }
{ j/w3 }
?&X6VNbU return CallNextHookEx( hHook, nCode, wParam, lParam );
$K,aLcu }
z?gJHN< d@w
I:
7 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
B[$SA-ZHi [2FXs52 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
6Edqg BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
J`x9XWYw R-h7c!ko 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:
aSK$#Xeu my} P\r. LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
.9ROa#7U;n {
G6J3F if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
h5Z\9`f[ {
J`V6zGgW //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
z[k2&=c SaveBmp();
N&ddO-r[s return FALSE;
xp&I~YPH }
9z-"JnM …… //其它处理及默认处理
m0#hG
x }
TxiJ?sDh* C9nNziws L*l( ~t)vF 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
mb/3
#) 2`},;i~[ 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
<T}#>xHs3 l9jcoVo. 二、编程步骤
^ID%pd 2MC\~"L< 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
'v,W
gPe P*LcWrK 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
Ltj}>.+ Mfz5:' 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
MVj@0W33m ^*r${Nj 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;
%z.G3\s0 cshUxabB 5、 添加代码,编译运行程序。
DTJ 6RF01z|~_ 三、程序代码
jab]!eY ~\/ J& ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
e,x@?L* #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
CVUDN2 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
QZfPd\Q5 #if _MSC_VER > 1000
.d fTv/n #pragma once
f^]AyU;F: #endif // _MSC_VER > 1000
@N(jd($E #ifndef __AFXWIN_H__
5FzRusNiA #error include 'stdafx.h' before including this file for PCH
she`_'?5 #endif
jTqba:q@ #include "resource.h" // main symbols
3xe8DD class CHookApp : public CWinApp
P]TT {
i~.[iZf| public:
Vy9n3W"FB1 CHookApp();
}n.h)Oz // Overrides
a_ P[J8j // ClassWizard generated virtual function overrides
*Z]|
Z4Q/` //{{AFX_VIRTUAL(CHookApp)
i-<=nD&?t public:
1_t Dp&UO virtual BOOL InitInstance();
wv7jh~x(4 virtual int ExitInstance();
!69^kIi$ //}}AFX_VIRTUAL
B -KOf //{{AFX_MSG(CHookApp)
ky#6M?
\ // NOTE - the ClassWizard will add and remove member functions here.
K c<z; // DO NOT EDIT what you see in these blocks of generated code !
2eK\$_b_ //}}AFX_MSG
!vB%Q$!x DECLARE_MESSAGE_MAP()
@v'D9 ? };
z>{KeX: LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
<\8 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
<Z;7=k BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
@b/2' BOOL InitHotkey();
P=@lkF!\# BOOL UnInit();
V588Leb? #endif
D7.P g5Vr2 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
+E:(-$"R #include "stdafx.h"
[0LqZ<\5 #include "hook.h"
;!}SgzSH} #include <windowsx.h>
pd1m/: #ifdef _DEBUG
hq*JQb;Y} #define new DEBUG_NEW
a(~YrA%~ #undef THIS_FILE
P~<93 static char THIS_FILE[] = __FILE__;
Tc(R-Wi #endif
6'ZnyWb #define MAX_KEY 100
"{k
)nr+7U #define CTRLBIT 0x04
TxvPfU? #define ALTBIT 0x02
}^ <zVdwp #define SHIFTBIT 0x01
>l1Yhxd_0* #pragma data_seg("shareddata")
>>cd3)b HHOOK hHook =NULL;
0%F.]+6[O4 UINT nHookCount =0;
l{U 3; static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
K)+l 6Q static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
F"H!CJJu& static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
3R*@m static int KeyCount =0;
N]}+F w\5 static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
/vDF<HVzm #pragma data_seg()
h /QP=Zd HINSTANCE hins;
fti|3c void VerifyWindow();
?v8k& q^q BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
]M(f^ //{{AFX_MSG_MAP(CHookApp)
d-sh6q5 // NOTE - the ClassWizard will add and remove mapping macros here.
} XU:DE // DO NOT EDIT what you see in these blocks of generated code!
_ICDtG^ //}}AFX_MSG_MAP
x2sOEkcQ END_MESSAGE_MAP()
PJ@ ,01 ls\E%d CHookApp::CHookApp()
p.] .M"A {
%QgAilj, // TODO: add construction code here,
@!/fvP // Place all significant initialization in InitInstance
~&lJT }
!s*''v* r)]CZ]) CHookApp theApp;
VQ<i$ I LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
&[Zap6] {
T\!SA BOOL bProcessed=FALSE;
9*+0j2uhQ if(HC_ACTION==nCode)
(+8xUc(w {
;T{/; if((lParam&0xc0000000)==0xc0000000){// Key up
So*Wk " switch(wParam)
P&3/nL$9N {
>DUE8hp;< case VK_MENU:
E9B*K2l^{ MaskBits&=~ALTBIT;
Z) i1?# break;
eQVPxt2N case VK_CONTROL:
"E|r 3cN MaskBits&=~CTRLBIT;
XQJ^)d00h break;
zO5u{ case VK_SHIFT:
B H0#Q5 MaskBits&=~SHIFTBIT;
!8@rK$DB break;
tP
Efz+1N default: //judge the key and send message
+F~0\#d break;
Ipz
1+
#s' }
z2Y_L8u2 for(int index=0;index<MAX_KEY;index++){
oUvk2]H if(hCallWnd[index]==NULL)
B+e_Y\Bu continue;
aMvK8C%7 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
QYTTP6 Gz+ {
A]iv)C;] SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
]6BmCh bProcessed=TRUE;
RQpIBsj }
{pe7]P? }
fAMD2C }
b4)*<Zp` else if((lParam&0xc000ffff)==1){ //Key down
_:gGD8 switch(wParam)
+dgo-)kP(_ {
#x5 N{8 case VK_MENU:
qHR^0& MaskBits|=ALTBIT;
XiRT|%j break;
g{v5mly case VK_CONTROL:
xZP >g MaskBits|=CTRLBIT;
&V#z kW break;
@4_rx u& case VK_SHIFT:
uRm _ MaskBits|=SHIFTBIT;
5]H))}9>d break;
c+8>EU AW default: //judge the key and send message
;5D@kS^ break;
3|K=%jr[ }
H-_^TB for(int index=0;index<MAX_KEY;index++)
Db#W/8
a8k {
qIDWl{b< if(hCallWnd[index]==NULL)
{1Ju}=69 continue;
AB2mt:^ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
N753 {
GJC!0{8; SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
H~?*KcZ 0\ bProcessed=TRUE;
Mhv1K|4s }
Q{AZ'XV }
HPtTv}l }
@],6SKbG6 if(!bProcessed){
!F+|Y"c for(int index=0;index<MAX_KEY;index++){
8h&oSOkQk, if(hCallWnd[index]==NULL)
p.rdSv(8' continue;
?iPZsV if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
7P/?wv9+n* SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
YN,y0t/cQ }
I&TTr7 }
),cQUB }
MkG`w, return CallNextHookEx( hHook, nCode, wParam, lParam );
MAE7A"la }
UF&0&`@ g08*}0-k BOOL InitHotkey()
'}jf#C1$c {
y|q@;*rGNa if(hHook!=NULL){
'1W!xQ}E nHookCount++;
6=ZRn gQ return TRUE;
(3
IZ }
`zdH1 p^w else
pN\)(:"8v hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
A Gv!c($ if(hHook!=NULL)
>I$B= nHookCount++;
H$z>OS_6U return (hHook!=NULL);
t8+?U^j }
eWb0^8_ BOOL UnInit()
S~+O`y^ {
o3Mf:;2c C if(nHookCount>1){
B#FHf
Z nHookCount--;
<Z{vC return TRUE;
_*O7l }
^oS$>6| BOOL unhooked = UnhookWindowsHookEx(hHook);
v1LKU if(unhooked==TRUE){
3>RcWy;1i nHookCount=0;
$Mdbto~ < hHook=NULL;
}5Yj }
&Fw[YGJayz return unhooked;
-glugVq }
1TKEm9j]u 6ayy[5tW BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
?q\FLb%"7 {
!n|#|.0m BOOL bAdded=FALSE;
*i@sUM?K
for(int index=0;index<MAX_KEY;index++){
z)}3**3'y if(hCallWnd[index]==0){
\I?w)CE@R hCallWnd[index]=hWnd;
ZAMeqPt HotKey[index]=cKey;
q[-|ZA bbr HotKeyMask[index]=cMask;
\Ke8W,)ew bAdded=TRUE;
b)N[[sOt KeyCount++;
*D2Nm9sl break;
59.$ULQVMY }
|~z3U> }
Kl{-z X return bAdded;
<3b'm*
}
bG"HD?A_ Re>AsnA[ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
AIb>pL{ {
<0#^7Z BOOL bRemoved=FALSE;
n=q=zn; for(int index=0;index<MAX_KEY;index++){
j.DHqHx if(hCallWnd[index]==hWnd){
Bz?l{4". if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
FKC\VF hCallWnd[index]=NULL;
I"-dTa HotKey[index]=0;
xOythvO HotKeyMask[index]=0;
w!\3ICB bRemoved=TRUE;
WSRy%# KeyCount--;
F+m[&MKL break;
KF+mZB }
uVGa(4u} }
+Gow5-( }
Oa!
m
return bRemoved;
@D~B{Hg }
`z9J`r=I e'34Pw!m void VerifyWindow()
wd/G|kNO {
T?n-x?e for(int i=0;i<MAX_KEY;i++){
}k7_'p&yk if(hCallWnd
!=NULL){ qNxB{0(D
if(!IsWindow(hCallWnd)){ 6W&_2a7*
hCallWnd=NULL; y%S})9
HotKey=0; %m eLW&
HotKeyMask=0; v8m`jxII64
KeyCount--; ~EEs}i
} z<B CLP
} F)SP aC4
} Lu=O+{*8
} T/l1qcf`wT
hJf2o
BOOL CHookApp::InitInstance() H=p`T+
{ n*<v]1
AFX_MANAGE_STATE(AfxGetStaticModuleState()); L&kr