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:
Y<lJj"G
~>:uMXyV2t 一、实现方法
"F
nH>g- 0fhz7\a^_< 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:
msKWb311u ,tt]C~\u #pragma data_seg("shareddata")
df}DJB HHOOK hHook =NULL; //钩子句柄
K&2{k+w UINT nHookCount =0; //挂接的程序数目
!9yOFd_ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
&rY73qfP' static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
yu ~Rk static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
^m^4LDt static int KeyCount =0;
/"w%?Ea static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
X
wvH #pragma data_seg()
?7Kl)p3 )erI3?k 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。
O,m0Xb2s]~ 7[=MgnmuC 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:
7noxUGmFw 9?8Yf(MC%u BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
u-yVc*<, cKey,UCHAR cMask)
9"T&P_
{
VKI`@rY4 BOOL bAdded=FALSE;
xaQO=[ for(int index=0;index<MAX_KEY;index++){
fO6i if(hCallWnd[index]==0){
/G}TPXA hCallWnd[index]=hWnd;
/_yJ;l/K HotKey[index]=cKey;
$9LI v HotKeyMask[index]=cMask;
9|y?jb5im bAdded=TRUE;
OsQB`
D KeyCount++;
*^|.bBG break;
.d}7c! }
Rn(6Fk? }
*qM)[XO return bAdded;
QLr.5Wcg> }
;;r}=0V*= //删除热键
PH6!T/2[ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
fpESuVKr {
bq+Q$#F2X BOOL bRemoved=FALSE;
h^Bp^V5# for(int index=0;index<MAX_KEY;index++){
~yrEB:w`_ if(hCallWnd[index]==hWnd){
G)|s(C! if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ZT;8Wvo hCallWnd[index]=NULL;
~hx__^]d HotKey[index]=0;
[^rMM1^,OB HotKeyMask[index]=0;
'
];| bRemoved=TRUE;
o \r6iO KeyCount--;
o3=2`BvJ break;
.(2Zoa }
57nSyd]PR }
g#??Mz }
h_xHQf return bRemoved;
nqnVFkGd9 }
'h]sq{ fWutB5?P *=b#>// DLL中的钩子函数如下:
gk-g!v&
d q.'[ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
*_Sx^`"X`l {
q!r4"#Y"@Z BOOL bProcessed=FALSE;
ZSs)AB_Pe/ if(HC_ACTION==nCode)
/E%r@Rui3$ {
x JXPtm if((lParam&0xc0000000)==0xc0000000){// 有键松开
D(z}c, switch(wParam)
b@p3iq: {
TmH'_t.*T~ case VK_MENU:
*|OP>N MaskBits&=~ALTBIT;
@U)k~z2Hk break;
-JMlk:~ case VK_CONTROL:
=
nIl$9 MaskBits&=~CTRLBIT;
j1Ng[ break;
vc r5 case VK_SHIFT:
cVR#\OM MaskBits&=~SHIFTBIT;
r=S6yq} break;
BZdryk:S default: //judge the key and send message
8i?Hh?Mf} break;
JGZxNUr^ }
BS(XEmJn&j for(int index=0;index<MAX_KEY;index++){
+^@;J?O if(hCallWnd[index]==NULL)
VK~ OL continue;
z}gfH| if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
jf|5}5kSlf {
0}:wM':G SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Wwf],Ya bProcessed=TRUE;
|cBeyqr }
p%?VW }
0=,vdT }
.3Ag6YI0N else if((lParam&0xc000ffff)==1){ //有键按下
83|7#L switch(wParam)
8'nxc#& {
=Y-ZI case VK_MENU:
%K$f2): MaskBits|=ALTBIT;
_$f XK break;
n>5/y
c"/q case VK_CONTROL:
#xlT,:_:) MaskBits|=CTRLBIT;
sC ^9 break;
\{Yi7V
Xv case VK_SHIFT:
A=+
|&+? t MaskBits|=SHIFTBIT;
a2vZ' break;
.w@o%AO_ default: //judge the key and send message
*It`<F| break;
|+|q`SwJ }
AfV
a[{E for(int index=0;index<MAX_KEY;index++){
c-ud $0)c if(hCallWnd[index]==NULL)
0~;Owu continue;
YR\pt8(z? if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Ck;>9> {
#+<"`}]N SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
jJ B+UF= bProcessed=TRUE;
.0gF&>I} }
2/coa+Qkv] }
M|l`2Hpe }
$!Pm*s if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
P*\h)F/3}t for(int index=0;index<MAX_KEY;index++){
:K#z~#n if(hCallWnd[index]==NULL)
vp#A D9h1 continue;
IeZgF> if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
TS~>9h\; SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
n!Dy-)!`O //lParam的意义可看MSDN中WM_KEYDOWN部分
o(w xu) }
nJ]oApb/- }
z(yJ/~m }
|d@%Vb_ return CallNextHookEx( hHook, nCode, wParam, lParam );
82z\^a }
jEkO#xI aJmSagr69C 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
lebwGW,! x?*) BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
`wzb}"gLsM BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
@Ft\~ +} 9 K.B 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
1F*3K3T { t\/i9CBn LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
aT[qJbp1 {
2D"n#O`y if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
N"+o=nS {
p;P"mp\' //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
wTu_Am SaveBmp();
^5:xSQ@: return FALSE;
]rpU3 3 }
6BnP"R. …… //其它处理及默认处理
m7|}PH"7 }
.o._`"V .d4L@{V )C@O7m*.4 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
=F B[<% rQuozbBb 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
Q^|ZoJS !sJ*0 二、编程步骤
)yOdRRP IO*}N" 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
9}=]oX!+V ixf~3Y8 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
hI^Hqv !ULU#2'1 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
MPtn$@ whA 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;
vz[-8 m:f Q7~9~ 5、 添加代码,编译运行程序。
>`3wEJ"< 74h[YyVi 三、程序代码
>E9:3&[F 06Irx^n ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
XVlZ:kz #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
s%{8$>8V. #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
sM4Qu./ #if _MSC_VER > 1000
y,i ~w |4 #pragma once
_0v+g1x #endif // _MSC_VER > 1000
P?zPb'UVqa #ifndef __AFXWIN_H__
^hc&rD)_ #error include 'stdafx.h' before including this file for PCH
Zgw;AY.R> #endif
D)]U+Qk #include "resource.h" // main symbols
(Ov{gj^ class CHookApp : public CWinApp
H(JgqbFB* {
{N \ri{| public:
RW?F{Jy{ CHookApp();
FE0}V}\=h // Overrides
FR7DuH/f) // ClassWizard generated virtual function overrides
*tWZ.I<< //{{AFX_VIRTUAL(CHookApp)
TpHvZ]c public:
wc&`/'<p virtual BOOL InitInstance();
'V*ixK8R0 virtual int ExitInstance();
{c7ZA%T~R //}}AFX_VIRTUAL
@scy v@5)F //{{AFX_MSG(CHookApp)
sULCYiT|Hn // NOTE - the ClassWizard will add and remove member functions here.
2/T4.[`t // DO NOT EDIT what you see in these blocks of generated code !
\~LwlO o%R //}}AFX_MSG
>nqDUGnEo> DECLARE_MESSAGE_MAP()
0ESxsba };
'aWrjfDy: LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
B8f BX!u/ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
>q}Ns^ .' BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
4TPAD)C BOOL InitHotkey();
JQo"<<[ BOOL UnInit();
)&nfV5@" #endif
pG|+\k/B _SW_I{fjr //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
RS8tE( #include "stdafx.h"
E1=WH-iA0 #include "hook.h"
H*gX90{!2 #include <windowsx.h>
DX*eN"z[ #ifdef _DEBUG
! H^,p$`[i #define new DEBUG_NEW
<hJ%]] #undef THIS_FILE
*hk8[ static char THIS_FILE[] = __FILE__;
D~(f7~c% #endif
MeP,8,n' #define MAX_KEY 100
]]EOCGZ" #define CTRLBIT 0x04
T3JM8 #define ALTBIT 0x02
M6j!_0j #define SHIFTBIT 0x01
[110[i^ #pragma data_seg("shareddata")
-MCDX^>P HHOOK hHook =NULL;
.# Jusd UINT nHookCount =0;
1-h"1UN2E static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
Xcy Xju#"p static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
]1^F static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
y5p)z" static int KeyCount =0;
t&oNC6 static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
77]6_ #pragma data_seg()
LdPA`oI3j HINSTANCE hins;
w[/_ o,R void VerifyWindow();
Qw,{"J BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
2i4&*&A //{{AFX_MSG_MAP(CHookApp)
:/.SrkN(A7 // NOTE - the ClassWizard will add and remove mapping macros here.
zFFip/z\ // DO NOT EDIT what you see in these blocks of generated code!
(FY<%.Pa //}}AFX_MSG_MAP
>U.f`24 END_MESSAGE_MAP()
8F;r$i2 ,drcJ CHookApp::CHookApp()
a%IJ8t+mn {
FEF $4)ROv // TODO: add construction code here,
|)4aIa // Place all significant initialization in InitInstance
T2%{pcdV/ }
pSPVY2qKX #C`IfP./ CHookApp theApp;
8M_p'AR\,y LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
]E:P-xTwaI {
zYz0R:@n+ BOOL bProcessed=FALSE;
w]&
o]VP if(HC_ACTION==nCode)
*=KX0%3 {
s^QXCmb$8 if((lParam&0xc0000000)==0xc0000000){// Key up
!e0OGf switch(wParam)
mZgYR~ {
`\]gNn'Q case VK_MENU:
VOa7qnh4:[ MaskBits&=~ALTBIT;
Ibbpy++d[ break;
n;w&}g case VK_CONTROL:
5TB==Fj ? MaskBits&=~CTRLBIT;
Vi5&%/Y break;
#A@d;U% case VK_SHIFT:
rmq^P;At MaskBits&=~SHIFTBIT;
jW<aAd break;
>~vZ+YO default: //judge the key and send message
`+c8;p'q break;
;Q}pmBkqB }
pn._u`xMV for(int index=0;index<MAX_KEY;index++){
yaw33/iN if(hCallWnd[index]==NULL)
)2YZ [~3 continue;
JKMcdD?' if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
fN-y8 {
t)62_nu SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
<8?jn*$;\ bProcessed=TRUE;
F,NS:mE }
pRTdP/(OQ }
n?EL\B }
q@6Je(H else if((lParam&0xc000ffff)==1){ //Key down
re%MT@L# switch(wParam)
0D=7Mef {
%CaUC' case VK_MENU:
F#
a)"$j; MaskBits|=ALTBIT;
NW*qw q break;
[-pB}1Dxb case VK_CONTROL:
B;6N.X(K MaskBits|=CTRLBIT;
rf:CB&u break;
8>(DQ"h case VK_SHIFT:
<zdo%~ba MaskBits|=SHIFTBIT;
e|~s'{3 break;
>8>}o4Q/X default: //judge the key and send message
<Ky6|&! break;
%J
'RO }
]B'H(o
R<| for(int index=0;index<MAX_KEY;index++)
V1= (^{p8 {
UB7H`)C} if(hCallWnd[index]==NULL)
5%Xny8
]|D continue;
=nTNL .SX if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
} F; Nh7? {
U(t_uc5q SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
r:n-?P bProcessed=TRUE;
4\?GA`@ }
N`Q[OFe }
~5xs$ub }
|n_es)A if(!bProcessed){
_);;@T for(int index=0;index<MAX_KEY;index++){
m@W\Pic,j. if(hCallWnd[index]==NULL)
}s7ibm' continue;
=C[2"Y4JK0 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
?7:?OX SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
ly)b=ph& }
+#/`4EnI }
WV8?zB1 }
B2uLfi$q return CallNextHookEx( hHook, nCode, wParam, lParam );
6x_tX }
~1`ZPLVG yN Bb(!u BOOL InitHotkey()
OlV'#D
{
J|Xu]fg0 if(hHook!=NULL){
KJf~9w9U nHookCount++;
wB0zFlP return TRUE;
TP5?%SlJ }
pSLv1d"9{ else
7z?rx hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
Q;3v ]h_ if(hHook!=NULL)
NP {O nHookCount++;
ji|`S\u#b return (hHook!=NULL);
_#nP->0) }
2EdKxw3$] BOOL UnInit()
)=
,Lfj8x {
)/:&i<Q: if(nHookCount>1){
M]Y72K^ nHookCount--;
#n[1%8l, return TRUE;
qC%[J:RwF }
kr_!AW<.tz BOOL unhooked = UnhookWindowsHookEx(hHook);
WG_20JdJY if(unhooked==TRUE){
r:&"#F nHookCount=0;
#0+`dI_5/ hHook=NULL;
fnUR]5\tc }
9J$8=UuxWG return unhooked;
'|\et aD }
X2MQa:yksP QqC4g] BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
W:8*Z8?7 {
BE;J/ BOOL bAdded=FALSE;
l[2 d{r for(int index=0;index<MAX_KEY;index++){
U~mv1V^. if(hCallWnd[index]==0){
n>w/T" hCallWnd[index]=hWnd;
Z(8'ki HotKey[index]=cKey;
G$5N8k[2 HotKeyMask[index]=cMask;
jQKlJi2xu bAdded=TRUE;
+n
$ {6/
KeyCount++;
S[b)`Wi D break;
@[qGoai }
z_dorDF8`> }
|vZ\tQ
return bAdded;
:.-z) C} }
[\M=w7 wXc"Car) BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
~ E)[!y {
+P7A`{Ae BOOL bRemoved=FALSE;
%0PdN@I for(int index=0;index<MAX_KEY;index++){
rpgr5> if(hCallWnd[index]==hWnd){
FT1h\K|a if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
?
[?{X~uq hCallWnd[index]=NULL;
S^GB\uJ HotKey[index]=0;
D&{7Av HotKeyMask[index]=0;
H?M#7K~[ bRemoved=TRUE;
3gW4\2|T KeyCount--;
?I` BbT} break;
w$9aTL7 }
C^@.GA }
1Ftl1uf }
6?/$K{AI return bRemoved;
zX-6]j; }
E6SGK,f0D OQ$77]XtvL void VerifyWindow()
:\@WY {
Hp_3BulS< for(int i=0;i<MAX_KEY;i++){
8c m,G if(hCallWnd
!=NULL){ T/
CI?sn
if(!IsWindow(hCallWnd)){ C7(kV{h$d
hCallWnd=NULL; 71+J{XOC
HotKey=0; TqNEU<S/t
HotKeyMask=0; "h/{YjUS
KeyCount--; td@F%*
} MOJ-q3H^W
} (lhbH]I
} jg?B][
} VT1W#@`e-
R/
7G
BOOL CHookApp::InitInstance() Urhh)i
{ . `lcxC
AFX_MANAGE_STATE(AfxGetStaticModuleState()); qoBm!|q
hins=AfxGetInstanceHandle(); [8/E ;h
InitHotkey(); /vFw5KUu
return CWinApp::InitInstance(); f/9]o
} +XU*NAD,!
EA4aZ6%
int CHookApp::ExitInstance() OGNjn9av
{ or/Y"\-!
VerifyWindow(); `LL#Ai a
UnInit(); 9rX[z :
return CWinApp::ExitInstance(); @`U78)]
} 0-EhDGa]r
-^8gZk/(W
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file @R >4b
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) E7+y
W
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ w}<BO>
z
#if _MSC_VER > 1000 6
$%^
#pragma once ;$(a+?
#endif // _MSC_VER > 1000 E9{Gaa/{
>Vc_.dR)E
class CCaptureDlg : public CDialog FsZF>vaV
{ Yt2_*K@rC
// Construction 02&m