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:
C\/xl#e<@
f!oT65Vmi 一、实现方法
%+8F'&X P_?gq>E8 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:
';TT4$(m W3IpHV #pragma data_seg("shareddata")
C ~<'rO}| HHOOK hHook =NULL; //钩子句柄
T*#/^%HSG UINT nHookCount =0; //挂接的程序数目
@ zs'Y8 static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
,4zmb`dP< static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
mQCeo}7N5 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
WFO4gB* static int KeyCount =0;
jNLw= static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
)~+E[| #pragma data_seg()
+=q$ x Ia 9:ze{ c $ 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。
LQtj~c>X-| |zQ4u 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:
{Or; =U #dJ^4P BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
CK,7^U cKey,UCHAR cMask)
#JgH}|&a$ {
"}q@Y= BOOL bAdded=FALSE;
OK{quM5 for(int index=0;index<MAX_KEY;index++){
:n0vQ5a if(hCallWnd[index]==0){
bu:S:` hCallWnd[index]=hWnd;
ln?v
j)j HotKey[index]=cKey;
kSR\RuY* HotKeyMask[index]=cMask;
gZLP\_CL bAdded=TRUE;
lDOCmdt@N KeyCount++;
:p]'32FA! break;
b4E:Wn9x }
Y' %^NP}o }
G?EoPh^m return bAdded;
iz8Bf; }
_CW(PsfY //删除热键
A*2
bA BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
_AQb6Nb
{
Sz^
veh? BOOL bRemoved=FALSE;
@\|_ for(int index=0;index<MAX_KEY;index++){
1u:
gFUb if(hCallWnd[index]==hWnd){
|+iws8xK? if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
LXbP 2 hCallWnd[index]=NULL;
K[ (NTp$E HotKey[index]=0;
FrTi+& < HotKeyMask[index]=0;
&d"G/6 bRemoved=TRUE;
)3~{L;q KeyCount--;
(iL|Sq&}b break;
H
*[_cqnv }
|&FkksNAl\ }
RLbKD> }
9?0^ap,T return bRemoved;
*^f<W6xc }
_9=Yvc= { jhr< a4XU?-sUh DLL中的钩子函数如下:
U@-^C"R >sK!F$ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
#=6E\&NC {
fjU8gV BOOL bProcessed=FALSE;
N'g>MBdI if(HC_ACTION==nCode)
'R
c,Mq' {
}
\XfH if((lParam&0xc0000000)==0xc0000000){// 有键松开
`}mcEl switch(wParam)
f7=((5N {
{5F-5YL+> case VK_MENU:
^
q<v{_ MaskBits&=~ALTBIT;
$e*ce94 break;
$Hj.{;eC/k case VK_CONTROL:
G*-b}f MaskBits&=~CTRLBIT;
T;,cN7>>O break;
kdl:Wt*4o case VK_SHIFT:
5<UVD:~z MaskBits&=~SHIFTBIT;
,QcF|~n break;
8>0e*jC default: //judge the key and send message
XzIl`eH break;
*.!Np9l,V }
.Yf:[`Q6g for(int index=0;index<MAX_KEY;index++){
VxVE if(hCallWnd[index]==NULL)
Jh
]i]7r continue;
pov)Z):}G< if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
gLy&esJl1 {
#wV8X`g SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
a'2$nbp} bProcessed=TRUE;
B)qWtMZx }
|h;0H` }
Kac' ;1 }
ly:q6i else if((lParam&0xc000ffff)==1){ //有键按下
n2oz"<?$S switch(wParam)
K2J\awX {
3+ @<lVew6 case VK_MENU:
tD+9kf2 MaskBits|=ALTBIT;
=zKhz8B( break;
ApAO/q case VK_CONTROL:
:E:38q,hG MaskBits|=CTRLBIT;
1`a5C.v break;
C!fMW+C@ case VK_SHIFT:
\3pc"^W MaskBits|=SHIFTBIT;
/7}It$|nhy break;
[[;e)SoA default: //judge the key and send message
T~Gvp0r}h break;
U-R6xxPZ }
#MRMNL@ for(int index=0;index<MAX_KEY;index++){
)pq;*~IBI if(hCallWnd[index]==NULL)
,M^ P! continue;
l]8D7(g if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
m+lvl {
vSi.txV2 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
5 N#3a0) bProcessed=TRUE;
X22[tqg;& }
k + H3Bq }
:TJv=T'p' }
jO!y_Y]B if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
yuat" Pg for(int index=0;index<MAX_KEY;index++){
@te!Jgu{ if(hCallWnd[index]==NULL)
.=X}cJ]`[ continue;
uf&myV7 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
$shoasSuI SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
:9^;Qv* //lParam的意义可看MSDN中WM_KEYDOWN部分
&(xH$htv1 }
i 7x7xtq }
L{h%f4Du# }
A29gz:F( return CallNextHookEx( hHook, nCode, wParam, lParam );
|j#C|V%kV }
]%?YZn<{ 1T-8K
r 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:
wPwXM! .ys6"V|31 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
~TSy<t~%- BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
gx\&_)w N Il=
W,/y 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:
)u/yF*:n 6^%68N1k LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
HN&Z2v {
FRg^c
kb" if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
Aq0S-HKF {
>rJnayLF //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
li0i" SaveBmp();
]>~)<
return FALSE;
M;p
em< }
@8;W \L$~1 …… //其它处理及默认处理
/J:bWr }
9Hc$G{[a $!8-? ?ML 5A
sP5 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。
,!7 H]4Qx 1e&QSzL 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。
h $L/<3oP6 ;uwRyd 二、编程步骤
]cGA~d |aT| l^2R@ 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";
UG'9*(* #ZYVc|sT+ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
5ZMR,SZhC $CY't'6Hn 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
-5I2ga ~:3QBMk:: 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
DsT>3 ,]+z)
5、 添加代码,编译运行程序。
\hM|(*DL WIv?}gi:
X 三、程序代码
\ aHVs U2ZD]q ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
\9/ b!A #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
O'W0q;rT #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
Yx eOI#L #if _MSC_VER > 1000
l)!n/x_ ! #pragma once
8erSt!oM #endif // _MSC_VER > 1000
>|twyb #ifndef __AFXWIN_H__
't6V:X #error include 'stdafx.h' before including this file for PCH
/)4I|"}R0I #endif
[$ejp>'Ud #include "resource.h" // main symbols
|b|&XB_<]Z class CHookApp : public CWinApp
)*,5"CO {
wYQ&C{D% public:
tb$LriN CHookApp();
_c,'>aH= // Overrides
+=.W<b // ClassWizard generated virtual function overrides
Kwg4sr5"D //{{AFX_VIRTUAL(CHookApp)
l PK
+$f$ public:
,=|ZB4HA virtual BOOL InitInstance();
}w1~K'ck}> virtual int ExitInstance();
QoG cWJ //}}AFX_VIRTUAL
*{yK
8 //{{AFX_MSG(CHookApp)
Q)LM-ZJKQ // NOTE - the ClassWizard will add and remove member functions here.
hED=u/ql[ // DO NOT EDIT what you see in these blocks of generated code !
<j5NFJ9 //}}AFX_MSG
Oh'Y0_oB> DECLARE_MESSAGE_MAP()
`~ * @q! };
R0L&*Bjm LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
4( 1(e BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
;~\MZYs3m BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
[&nh5|f BOOL InitHotkey();
~d6DD;`K BOOL UnInit();
"Q?k'^@ #endif
3Ei5pX =g 'ul~7h;n //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Ygl%eP%Z #include "stdafx.h"
I;Bjfv5 #include "hook.h"
UGuxV+Nwf #include <windowsx.h>
Fm #w2o #ifdef _DEBUG
JM\m)RH0 #define new DEBUG_NEW
^1L>l9F #undef THIS_FILE
])Qs {hs~s static char THIS_FILE[] = __FILE__;
|"9 #bU #endif
E[bd@[N
8 #define MAX_KEY 100
! ykx^z #define CTRLBIT 0x04
XLH+C ]pfr #define ALTBIT 0x02
vsr[ur[eP #define SHIFTBIT 0x01
tc!wLnhG #pragma data_seg("shareddata")
k:#P|z$UD HHOOK hHook =NULL;
d\FJFMW*9 UINT nHookCount =0;
K!] 1oy'V static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
jMN[J|us51 static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
Xixqxm*8 static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
,$
^C4I static int KeyCount =0;
[w&$| h:; static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
+C(/Lyo} #pragma data_seg()
EB_NK HINSTANCE hins;
ea00\ void VerifyWindow();
zA!0l*H BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
w&B#goS //{{AFX_MSG_MAP(CHookApp)
]<q[Do8k // NOTE - the ClassWizard will add and remove mapping macros here.
qg}O/K // DO NOT EDIT what you see in these blocks of generated code!
?1[\! //}}AFX_MSG_MAP
jD`d#R END_MESSAGE_MAP()
*r$+&8V\n
u*#ZXW CHookApp::CHookApp()
Hw-Z {
f4guz // TODO: add construction code here,
Kbb78S30 // Place all significant initialization in InitInstance
!\,kZ|#> }
e4z1`YLsG +5&wOgx CHookApp theApp;
k!KDWb
LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
-~QHqU. {
Gsc\/4Wx BOOL bProcessed=FALSE;
Z+StB15 if(HC_ACTION==nCode)
3:f[gV9K {
Xj5~%DZp if((lParam&0xc0000000)==0xc0000000){// Key up
XFh>U7z. switch(wParam)
yGsz2T;w {
B-T/V-c7 case VK_MENU:
"n=vN<8(o MaskBits&=~ALTBIT;
V2<?ol break;
\#>T~.Y7K case VK_CONTROL:
YTjkPj: MaskBits&=~CTRLBIT;
W":PG68 break;
WwUv5GZTW case VK_SHIFT:
C{q :_M; MaskBits&=~SHIFTBIT;
ZZ.m(ATR break;
D^-7JbE] default: //judge the key and send message
>N?2"" break;
yx<WSgWZ[ }
Qo1eXMW for(int index=0;index<MAX_KEY;index++){
60)iw4<wf if(hCallWnd[index]==NULL)
hAjM1UQ,Y continue;
}irn'`I if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
bC3 F {
/De^
SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
@5[kcU> bProcessed=TRUE;
?^EXTU85`" }
f5GdZ_ }
6Kj'ZyVL }
rX; Ys2vQ* else if((lParam&0xc000ffff)==1){ //Key down
\^V`ds*. switch(wParam)
Zxb_K {
fI7j):h; case VK_MENU:
|P.6< MaskBits|=ALTBIT;
i9D0]3/> break;
k,uK6$Z case VK_CONTROL:
q;:6_Qr MaskBits|=CTRLBIT;
2EK%N'H break;
$
A9%UhV case VK_SHIFT:
@YH+cG| MaskBits|=SHIFTBIT;
nWvuaQ0} break;
V&|!RxWK default: //judge the key and send message
IB`>'~s&A break;
"aFhkPdWn }
QERU5|.wc for(int index=0;index<MAX_KEY;index++)
F>X-w+b4r {
"sgjWo6 if(hCallWnd[index]==NULL)
P/ oXDI8 continue;
rO:u6."_ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
cf7v[ZZ} {
z 8*8OWM SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
KnNh9^4"\2 bProcessed=TRUE;
}rdIUlVO\ }
4A3nO<oMF }
}I!hOD>]O }
wfjc/u9W6R if(!bProcessed){
}BmS)Jq for(int index=0;index<MAX_KEY;index++){
U5]pi+r if(hCallWnd[index]==NULL)
t
nS+5F continue;
_7D _72 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
i0s6aAhgJ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
2nFy`|aA% }
Y=
7%+WyD }
G8I Y# }
T'fcc6D5p return CallNextHookEx( hHook, nCode, wParam, lParam );
oQ7]=| }
zLD|/` O3.C:?;x BOOL InitHotkey()
w~@-9<^K]v {
lZQ/W:OE if(hHook!=NULL){
sgr=w+",Q nHookCount++;
%ObD2)s6:^ return TRUE;
3[XQR8o }
h)v^q: =' else
^MmC$U^n hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
%Z8vdU# l if(hHook!=NULL)
M]-VHI[&W nHookCount++;
dxj*Q "K return (hHook!=NULL);
j4R 4H; }
%o}(sShS BOOL UnInit()
{NCF6Mk {
s(_+!d6 if(nHookCount>1){
cW``M.d'F nHookCount--;
c[ht`!P return TRUE;
3g~^LZ66 }
$iM=4
3W BOOL unhooked = UnhookWindowsHookEx(hHook);
QI_59f> if(unhooked==TRUE){
]/T-t1D nHookCount=0;
XW L^ hHook=NULL;
&)pK%SAM }
fB+b}aoV return unhooked;
ap}5ElMR }
YGsS4ia*4i m/`IGT5J BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
fRm}S>Nibb {
5v^L9!`@%v BOOL bAdded=FALSE;
qXXGF_Q for(int index=0;index<MAX_KEY;index++){
zEw>SP1, if(hCallWnd[index]==0){
A7P`lJgv hCallWnd[index]=hWnd;
{5%/ T, HotKey[index]=cKey;
+^6}
HotKeyMask[index]=cMask;
oY`qI nM_ bAdded=TRUE;
CT d|` KeyCount++;
jLcHY-P0V break;
QT#6'>&7-b }
G*\h\@ }
,kgF2K! return bAdded;
)uP[!LV[e }
(P==VZQg 1'G8o=~ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
%q_Miu@ {
7?)/>lx\>$ BOOL bRemoved=FALSE;
:Y)to/h for(int index=0;index<MAX_KEY;index++){
(RXS~8 if(hCallWnd[index]==hWnd){
{Ts:ZI+
8d if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
e@F|NCQ.9 hCallWnd[index]=NULL;
r-w2\ 2 HotKey[index]=0;
2:$ k HotKeyMask[index]=0;
uG>nV bRemoved=TRUE;
gUB{Bh($Y KeyCount--;
K%}}fw2RMN break;
Y(GN4@`S }
J -Qh/d%] }
S:Tm23pe }
' eO/PnYW return bRemoved;
CsS p=( }
?kt=z4h9( jnoL2JR[=- void VerifyWindow()
30FykNh {
~_ !ts{[E for(int i=0;i<MAX_KEY;i++){
&WZP2Q| if(hCallWnd
!=NULL){ MY-.t-3
if(!IsWindow(hCallWnd)){ a%hGZCI
hCallWnd=NULL; >Csbjf6
HotKey=0; ^Y^"'"
HotKeyMask=0; c!&Qj
KeyCount--; s0{
NsK>
} FQf#*
} Xy#VQ{!
} JZ`L%
} N_C_O$j
<?$kI>Ot
BOOL CHookApp::InitInstance() H?}wl%
{ -Gsl[Rc0H;
AFX_MANAGE_STATE(AfxGetStaticModuleState()); um8AdiK
hins=AfxGetInstanceHandle(); R9.HD?H@
InitHotkey(); ~4
FDKUC
return CWinApp::InitInstance(); g=A$<