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:
"U"fsAc#
8_w6% md 一、实现方法
-:pVDxO jnbR}a=fJ 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:
2O@ON/ )B+o
F7 #pragma data_seg("shareddata")
ezbk@no HHOOK hHook =NULL; //钩子句柄
X@}7 #Vt UINT nHookCount =0; //挂接的程序数目
ULu@" static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
tmoCy0qWz static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
);AtFP0Y static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
DJ7ak>"R
static int KeyCount =0;
kjp~:Bg_( static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
EPLHw #pragma data_seg()
PX_9i@ZG sC[#R.eq 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。
6Iv};f"Y xzA!,75@U 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:
iG"v G~.VW48{n BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
U&:-Vf~& cKey,UCHAR cMask)
+PWm=;tcC {
eN|zD?ba& BOOL bAdded=FALSE;
3I)oqS@q' for(int index=0;index<MAX_KEY;index++){
8YE4ln if(hCallWnd[index]==0){
a6ryyt 5 hCallWnd[index]=hWnd;
e 2NF. HotKey[index]=cKey;
S1)g\Lv HotKeyMask[index]=cMask;
".Q]FE@> bAdded=TRUE;
g8&& W_BI KeyCount++;
g#l!b%$ break;
@oj_E0i3 }
W7~_XI }
i$3#/*Y7_L return bAdded;
:.l\lj0Yf }
^/Yk*Ny //删除热键
s"nntC BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
RT'5i$q[ {
WdC7CK BOOL bRemoved=FALSE;
!@Vj&>mH$ for(int index=0;index<MAX_KEY;index++){
A>F&b1 if(hCallWnd[index]==hWnd){
I
Gb'ii=A if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
bzZdj6>kX hCallWnd[index]=NULL;
X=6L-^o) HotKey[index]=0;
#=Xa(<t HotKeyMask[index]=0;
d/*EuJYin< bRemoved=TRUE;
>.C$2bW<L KeyCount--;
:18}$ break;
cMy?& }
m |+zMf& }
Ebi~gGo }
rc%*g3ryLG return bRemoved;
JPT&!%~ }
5qqU8I +U<Ae^V tC f@v'1t DLL中的钩子函数如下:
^( C,LVP< WwSyw?T LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
5y0LkuRR: {
#vBSg BOOL bProcessed=FALSE;
JL:B4f%}B if(HC_ACTION==nCode)
ov!L8
9`[u {
{Y]3t9!\ if((lParam&0xc0000000)==0xc0000000){// 有键松开
ND 8;1+3 switch(wParam)
aM8z_j!!u {
P8CIKoKCV case VK_MENU:
nu|odP MaskBits&=~ALTBIT;
)5;|mV break;
j=>WWlZ case VK_CONTROL:
F
'HYWH0? MaskBits&=~CTRLBIT;
a5@lWpQsV break;
/h&>tYVio case VK_SHIFT:
@
eP[*Q MaskBits&=~SHIFTBIT;
Gn10)Uf8X break;
Xd~li fF default: //judge the key and send message
.8|5;!`WB break;
*;.:UR[i }
jN7Z}1` for(int index=0;index<MAX_KEY;index++){
a9nXh6 if(hCallWnd[index]==NULL)
\ $9n
` continue;
zjx'nK{eI if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
W?12'EG}xa {
,76nDXy` SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
1
7hXg"B bProcessed=TRUE;
|qibO \_ }
@eDL j} }
q]*:RI?wGT }
<{1 3Nd'o else if((lParam&0xc000ffff)==1){ //有键按下
K9'AYFse switch(wParam)
_P]k6z+ {
cFG%Ew@ case VK_MENU:
H*dQT y, MaskBits|=ALTBIT;
X_I.f6v{ break;
|<7nf7 5c} case VK_CONTROL:
\RTX fe-` MaskBits|=CTRLBIT;
9hs7B!3pc> break;
TqMy">> case VK_SHIFT:
r+Y]S-o: MaskBits|=SHIFTBIT;
P1QGfp0-J break;
ps?B;P default: //judge the key and send message
Wv)2dD2I break;
uI[lrMQYa }
[k6 5i for(int index=0;index<MAX_KEY;index++){
o#&;,9 if(hCallWnd[index]==NULL)
)kNyl@m continue;
;;- I<TL if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
y3C$%yv0 {
r`/tb^ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
*gzX=*;x+? bProcessed=TRUE;
X'>]z'0W }
t%<d}QuHW }
$PNIuC?= }
[&FWR if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
^Q4m1?
40 for(int index=0;index<MAX_KEY;index++){
3AD^B\<gB if(hCallWnd[index]==NULL)
dPRGL
hWF continue;
bKH8/*Yk if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
ve /Q6j{ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
} Pc6_# //lParam的意义可看MSDN中WM_KEYDOWN部分
"-TIao# }
~?{@0,$ }
K]q OLtc }
qN_jsJ return CallNextHookEx( hHook, nCode, wParam, lParam );
u37@9 }
=X2EF k^.9;FmQ 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:
pOip$Z |&TRN1 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
NLC}XL BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Aj4i}pT HtIM8z#/ 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
p_QL{gn \^3\_T&6 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
:U<`iJwY {
h^bbU. if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
@$;"nVZ4v {
nMXSpX>!| //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
|k> _
jO SaveBmp();
|k+Y >I& return FALSE;
o$YL\ <qp }
/W/ =OPe …… //其它处理及默认处理
c0jC84*v }
x5 3aGi| #G^?4Za Pd\S{ Y~wk 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
T.aY{Y ;
eq^m,oz 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
hHdH#-O:4" rRL:]%POT 二、编程步骤
(~N&ov Qg9 N?e{z 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
5+'1 :Sa(i +dk}$w[g 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
RpR;1ktF> 2RidI&?c< 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;
S!k cC-7 ,)nO 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;
zN {'@B c:4M|t= 5、 添加代码,编译运行程序。
Sim\+SL{# _CBG? 三、程序代码
/A4zR @%fNB,H` ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
!iA0u #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
@]t} bF] #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
G0|j3y9$ #if _MSC_VER > 1000
:e`;["(, #pragma once
uMtq4. #endif // _MSC_VER > 1000
)VID
;l;4 #ifndef __AFXWIN_H__
M;,Q8z% #error include 'stdafx.h' before including this file for PCH
Z~ VOO7|m #endif
KQj5o>} 6 #include "resource.h" // main symbols
b'4{l[3~nl class CHookApp : public CWinApp
L\XnTL{ {
WrQe'ny public:
Dx/BxqG6}_ CHookApp();
"m.j cKt // Overrides
hMh8)S // ClassWizard generated virtual function overrides
nc!P
!M //{{AFX_VIRTUAL(CHookApp)
oQ1>*[e<u public:
!v;N@C3C virtual BOOL InitInstance();
)" q$g& virtual int ExitInstance();
7,ysixY //}}AFX_VIRTUAL
*Fb]lM7D //{{AFX_MSG(CHookApp)
@r^a/]5D // NOTE - the ClassWizard will add and remove member functions here.
/qa{*"2Qo // DO NOT EDIT what you see in these blocks of generated code !
K>hQls+ //}}AFX_MSG
`+[Ct08 DECLARE_MESSAGE_MAP()
$n\{6Rwb };
$8vZiB!" LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
kAA1+rG BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
}lt5!u~} BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
+sq'\Tbp BOOL InitHotkey();
n]^zIe^6 BOOL UnInit();
E1 IT>_ #endif
\ :To\6\Ri v1h\
6r' //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Oo^kV:.) #include "stdafx.h"
^)oBa=jL4 #include "hook.h"
m/@ ;N,K #include <windowsx.h>
Z;Q2tT/F #ifdef _DEBUG
h|qTMwPr #define new DEBUG_NEW
4&%0% #undef THIS_FILE
SO @d\H static char THIS_FILE[] = __FILE__;
n-zAkKM #endif
)#S;H$@$ #define MAX_KEY 100
KUJCkwQ #define CTRLBIT 0x04
*-uA\ #define ALTBIT 0x02
U;
-2)+ #define SHIFTBIT 0x01
yp}J+/PX} #pragma data_seg("shareddata")
x*>@knP<- HHOOK hHook =NULL;
1eHU!{<fqm UINT nHookCount =0;
FQY{[QvF~ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
t5O '7x static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
tVfZ~qJ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
^UU@7cSi|G static int KeyCount =0;
Uh[MBwK static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
XZ%3PMq #pragma data_seg()
de7
\~$ HINSTANCE hins;
U]/iPG&_ void VerifyWindow();
7R5m|h`M BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
Q1kZ+b& //{{AFX_MSG_MAP(CHookApp)
B&fH
FyK1n // NOTE - the ClassWizard will add and remove mapping macros here.
;|qbz]t2( // DO NOT EDIT what you see in these blocks of generated code!
arK(dg~S //}}AFX_MSG_MAP
p1F{ v^ END_MESSAGE_MAP()
mD5Vsy{Pb _oz1'}= CHookApp::CHookApp()
\/XU v( {
<C1w?d$9I // TODO: add construction code here,
osM[Xv // Place all significant initialization in InitInstance
K<wg-JgA }
Vh ?5 pTB1 I3=.u CHookApp theApp;
d+qeZGg^A LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
\jmT#Gt`9 {
V36u%zdX5n BOOL bProcessed=FALSE;
]hMs:$} if(HC_ACTION==nCode)
*""iXi[ {
u+lNcyp"MW if((lParam&0xc0000000)==0xc0000000){// Key up
G^ShN45 switch(wParam)
(N6=+dNY {
x)R1aq case VK_MENU:
%45*DT MaskBits&=~ALTBIT;
c( _R
xLJ break;
kfY. 9$(d case VK_CONTROL:
eC[G4 MaskBits&=~CTRLBIT;
63`5A3rii break;
U(+%iD60i case VK_SHIFT:
Qo/pz2N MaskBits&=~SHIFTBIT;
fBb:J + break;
=qvn?I^/ default: //judge the key and send message
I!"/ I8Y break;
TH"<6*f2L }
FKtG for(int index=0;index<MAX_KEY;index++){
Alv"D if(hCallWnd[index]==NULL)
W K(GR\@ continue;
T|&u? if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
zh{I;~syh {
_b`/QSL SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
ki'<qa bProcessed=TRUE;
]k$:sX }
>guX,hx^ }
e6>[Z C }
HHerL%/ else if((lParam&0xc000ffff)==1){ //Key down
B qo#cnlG switch(wParam)
-k
}LW4 {
D;h JK-Y case VK_MENU:
%(S!/(LWW MaskBits|=ALTBIT;
]5Q)mWF break;
tb>Q#QB&u case VK_CONTROL:
Vp1 Q^`a{G MaskBits|=CTRLBIT;
k$.l^H u break;
og1Cj{0 case VK_SHIFT:
P_P~c~o MaskBits|=SHIFTBIT;
e< G[!m break;
BC85#sbl default: //judge the key and send message
xouBBb= break;
6o^O%:0g }
L*P*^I^1 for(int index=0;index<MAX_KEY;index++)
*&5./WEOH {
f7a"}.D$ if(hCallWnd[index]==NULL)
[,Y;#; continue;
A9WOu*G1O if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
BwYR" {
]vuxeu[cu, SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
DB'3h7T bProcessed=TRUE;
-j^G4J }
ZSB;4 ?:h }
.B!L+M< [ }
MnQ 6 !1Z if(!bProcessed){
;T<'GP'/r for(int index=0;index<MAX_KEY;index++){
}5d|y* if(hCallWnd[index]==NULL)
rm<`H(cT continue;
ZC &~InN if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
(9)uZ-BF, SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
R_IT${O }
L(/wsw~y*
}
']sIU;h3 }
'<wZe.Q! return CallNextHookEx( hHook, nCode, wParam, lParam );
CbMClnF }
V'AZs; 3ZAzv en BOOL InitHotkey()
L @8[. {
^56#{~%^? if(hHook!=NULL){
602=qb nHookCount++;
<$%Y#I'zX return TRUE;
<*opVy^ }
tY?evsVgz else
XE|"n hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
0[s<!k9= if(hHook!=NULL)
w.Kp[ nHookCount++;
(!<G` ;}u return (hHook!=NULL);
Z?'?+48xv4 }
e)4L}a BOOL UnInit()
-vS7 %Fbr {
3UGdXufw if(nHookCount>1){
5{#ya2 nHookCount--;
KkZ o|\V return TRUE;
}}v28"\TA }
SA6.g2pFz BOOL unhooked = UnhookWindowsHookEx(hHook);
jhE3@c@pT if(unhooked==TRUE){
28o!>* nHookCount=0;
QsPL^ Ny hHook=NULL;
YwF\ }
5?MKx!% return unhooked;
Jz)c|8U }
G;bE_O JZ0u/x5 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
j*1O(p+ {
xW'(]Z7_ BOOL bAdded=FALSE;
Z65]| for(int index=0;index<MAX_KEY;index++){
2<+9lk if(hCallWnd[index]==0){
%-[U;pJe; hCallWnd[index]=hWnd;
1)h+xY HotKey[index]=cKey;
24/ ^_Td HotKeyMask[index]=cMask;
2o-Ie/"d\ bAdded=TRUE;
2;=xHt KeyCount++;
[y$sJF7;I break;
L-(.v* }
6}e"$Ee}9 }
8Dy;'BtT return bAdded;
qQUCK }
-AxO1
qO Gd%E337d BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
]Syr{| {
69u"/7X BOOL bRemoved=FALSE;
,_2ZKO/k$ for(int index=0;index<MAX_KEY;index++){
4&([<gyR< if(hCallWnd[index]==hWnd){
Q{+&3KXH if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
IXef}%1N? hCallWnd[index]=NULL;
[Dq!t1 HotKey[index]=0;
:;]iUjiC8 HotKeyMask[index]=0;
P>3
;M'KsO bRemoved=TRUE;
d%: KeyCount--;
m|w-}s, break;
7}e73 }
("B[P/ }
3@/\j^U }
nuip return bRemoved;
[~<X|_LG }
:v!e8kM\x usR:-1{ void VerifyWindow()
[_h/DhC:+ {
a.yCd/ for(int i=0;i<MAX_KEY;i++){
TxD,A0 if(hCallWnd
!=NULL){ MIJ^n(-G
if(!IsWindow(hCallWnd)){ lef,-{X-
hCallWnd=NULL; RHc-kggk!
HotKey=0; ~S, R`wo
HotKeyMask=0; xQ=sZv^M
KeyCount--; j r<`@
} l$~3_3+
} As;@T$G
} ~<?+(V^D
} "Vg1'd}f
R>iRnrn:-
BOOL CHookApp::InitInstance() <n)J~B^
{ 0 xUw}T6
AFX_MANAGE_STATE(AfxGetStaticModuleState()); N:]71+
hins=AfxGetInstanceHandle(); +;P8QZK6
InitHotkey(); ;|.^_Xs
return CWinApp::InitInstance(); em+dQ15
} O"$uw
I0
78[3b
int CHookApp::ExitInstance() O#,Uz2
{ 8T7E.guYr
VerifyWindow(); 0@K?'6
UnInit(); K/,y"DUN&
return CWinApp::ExitInstance(); )]/gu\90
} b1(7<o
J3F-Yl|
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file aL9yNj}2
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) /!l$Y?
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ g ni=S~u
#if _MSC_VER > 1000 4&}V3"lg
#pragma once CWP),]#n
#endif // _MSC_VER > 1000 Ry@QJn I<
</UUvMf"
class CCaptureDlg : public CDialog uANG_sX^n
{ .l| [e
// Construction 0W92Z@_GY
public: Vq'\`$_
BOOL bTray; 7,MDFO{n
BOOL bRegistered; -YXNB[C
BOOL RegisterHotkey(); _2eRH@T
UCHAR cKey; LW={| 3}
UCHAR cMask; Z*+0gJ<Y
void DeleteIcon(); L}E~CiL0n
void AddIcon(); S(B$[)(
UINT nCount; UlG8c~p
void SaveBmp(); p#5U[@TK
CCaptureDlg(CWnd* pParent = NULL); // standard constructor ^#|Sl D]
// Dialog Data -/x=`S*
//{{AFX_DATA(CCaptureDlg) #.<Uy."z2
enum { IDD = IDD_CAPTURE_DIALOG }; eGwO!Lv}B
CComboBox m_Key; :%6OFO$z
BOOL m_bControl; <Km
^>9
BOOL m_bAlt; Ic 5TtN~/>
BOOL m_bShift; 5r&bk`
CString m_Path; aVg~/
CString m_Number; 8#m,TOp
//}}AFX_DATA _d|CO
// ClassWizard generated virtual function overrides /|<Pn!}J
//{{AFX_VIRTUAL(CCaptureDlg) zBQV2.@
public: J0ysZ]
virtual BOOL PreTranslateMessage(MSG* pMsg); YFJw<5&
protected: VjI=5)+~
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support HT`k-}ho,
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); $U_M|Xa
//}}AFX_VIRTUAL 8a,uM :
// Implementation ty"|yA
protected: lm;Dy*|<