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:
~:"//%M3l
d01]5'f?o 一、实现方法
2Afg.-7EP
o+FDkqEN 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[[X5 ;0:[X+"( #pragma data_seg("shareddata")
sk~inIj- HHOOK hHook =NULL; //钩子句柄
6{?B`gm7g UINT nHookCount =0; //挂接的程序数目
7NQEn Al static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
A0gRX] static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
Kr@6m80E5 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
u:%Ln_S static int KeyCount =0;
V*F |Yo: static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
")eY{C #pragma data_seg()
}9 I,p$ [ih^VlZ 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。
vW`[CEm^X QJtO~~- 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:
MW|:'D` _+}#
BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
v1\/ dQK cKey,UCHAR cMask)
iO{LsG*5Z {
gE~LPwM BOOL bAdded=FALSE;
D`2w>{Y for(int index=0;index<MAX_KEY;index++){
4~z-&>% if(hCallWnd[index]==0){
3?bTs = hCallWnd[index]=hWnd;
F4=V*/7 HotKey[index]=cKey;
M. fA5rJ^ HotKeyMask[index]=cMask;
K5}0!_)G bAdded=TRUE;
O{ |Ug~ KeyCount++;
#7p!xf^ break;
L=V.@? }
^D A<=C-[! }
#]@|mf
q return bAdded;
;]^% 6B n }
IRT0
//删除热键
*b\&R%6dR BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
ecyN};V> {
5N:IH@ BOOL bRemoved=FALSE;
tYCVVs`? for(int index=0;index<MAX_KEY;index++){
Z^_gS&nDa~ if(hCallWnd[index]==hWnd){
p'\zL:3 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
#;/ob- hCallWnd[index]=NULL;
ZhY03>X HotKey[index]=0;
^JAp#?N^9 HotKeyMask[index]=0;
)F,z pGG bRemoved=TRUE;
!uqp?L^; KeyCount--;
qpV"ii break;
- |4 Oq }
hd@jm^k }
~9n30j%]s }
>Et~h65d5 return bRemoved;
zV8{|-2]No }
|G/WS0 w$"^)EG,7 -lm)xpp1 DLL中的钩子函数如下:
"D'"uMS`H USZBk0$ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
H`1q8}m {
63/a 0Yn BOOL bProcessed=FALSE;
st)qw]Dn;Y if(HC_ACTION==nCode)
afE)yu` {
-`UOqjb]3 if((lParam&0xc0000000)==0xc0000000){// 有键松开
m~-O}i~) switch(wParam)
o+Fm+5t; {
5&qBG@Hw] case VK_MENU:
CV)K=Br5&_ MaskBits&=~ALTBIT;
izs=5 break;
f4$sH/ 2#v case VK_CONTROL:
DMlr%)@{ MaskBits&=~CTRLBIT;
d .%2QkL break;
|G_, 1$ case VK_SHIFT:
g)7@EU2 MaskBits&=~SHIFTBIT;
*Sps^Wl break;
G|u)eW default: //judge the key and send message
9 !$&1|,* break;
%<fs \J^k }
AG><5 } for(int index=0;index<MAX_KEY;index++){
6Ta+f3V if(hCallWnd[index]==NULL)
-kHJH><j continue;
A?ho<@^ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
snYeo?|b {
_|T{2LvwT SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
z_Hkw3? bProcessed=TRUE;
M4(57b[` }
q1v7(`O }
"z*.Bk }
5p6/dlN-a else if((lParam&0xc000ffff)==1){ //有键按下
E1SWZ&'; switch(wParam)
z/fSstN {
TbLU[(m-n case VK_MENU:
(,KzyR=*' MaskBits|=ALTBIT;
e=3C*+lq\ break;
5zh6l+S[ case VK_CONTROL:
A1r%cs MaskBits|=CTRLBIT;
_]-8gr-T break;
g)=$zXWhP case VK_SHIFT:
Kj)sL0 MaskBits|=SHIFTBIT;
%a
FZbLK break;
2qojU%fiH default: //judge the key and send message
W =;,ls break;
oY0*2~sg }
mE_% for(int index=0;index<MAX_KEY;index++){
yEk|(6+^ if(hCallWnd[index]==NULL)
v|KIVBkbT continue;
o")"^@Zhi if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
L9XfR$7,z {
TQb@szp:| SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
)_\ ;l%& bProcessed=TRUE;
H4sW%nZ0 }
D+BiclJ }
#!E`%'
s] }
P j,H] if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
[oXSjLQm[ for(int index=0;index<MAX_KEY;index++){
v 2p if(hCallWnd[index]==NULL)
+ K`.ck continue;
TGU7o:2 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
-agB ]j SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
QmSMDWkh //lParam的意义可看MSDN中WM_KEYDOWN部分
@$!6u0x }
,i|K} Y& }
x2a
?ugQ }
ID`Ot{ y return CallNextHookEx( hHook, nCode, wParam, lParam );
ZZZ`@pXm; }
Thu_`QP^ e$_gOwB 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
S>r}3,]S po\jhfn BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
SvQ|SKE': BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
bq)1'beW (+;D~iN` k 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
)">#bu$ 6P}?+ Gc LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
YFPse.2$a {
<bo^u w if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
i7PS=]TK\ {
l)o!&]2 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
]
Ok &%- SaveBmp();
7w" !"W# return FALSE;
9H;Os:"\| }
_
Pzgn@D …… //其它处理及默认处理
qoH:_o8ClO }
7Ok-T10 `GBJa k ,/GFD[SQ 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
Te~jYkCd rir,|y, 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
jD"nEp- xzOvc<u 二、编程步骤
)m3emMO2 9eq)WI/ 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
A^6z.MdYZ v;G/8>GRy 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
?lgE9I] X_nbNql 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
xu"-Uj1 UMBeY[? 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
-6uLww=w4 aM1WC 'c&) 5、 添加代码,编译运行程序。
+PWm=;tcC 0PFC%x 三、程序代码
B8T5?bl LgX2KU" ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
yx&}bu\ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
## vP(M$ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
~N;
dX[@BT #if _MSC_VER > 1000
J Q*~le* #pragma once
p=eSJ* #endif // _MSC_VER > 1000
CdCY#$Z #ifndef __AFXWIN_H__
*^7^g!=z2 #error include 'stdafx.h' before including this file for PCH
% rnRy<9 #endif
tC$+;_=+F #include "resource.h" // main symbols
4IB`7QJq class CHookApp : public CWinApp
N4-Y0BO {
(QqeMG,Y public:
MFO%F) 5 CHookApp();
@>~S$nw/ // Overrides
jt323hHth // ClassWizard generated virtual function overrides
qFDy)4H) //{{AFX_VIRTUAL(CHookApp)
2,B^OZmw public:
!@Vj&>mH$ virtual BOOL InitInstance();
imwn)]L R virtual int ExitInstance();
bT9:9LP //}}AFX_VIRTUAL
%jq
R^F:J //{{AFX_MSG(CHookApp)
j!Ys/D // NOTE - the ClassWizard will add and remove member functions here.
*kF/yN // DO NOT EDIT what you see in these blocks of generated code !
.3Smqwm=Y //}}AFX_MSG
;UX9Em DECLARE_MESSAGE_MAP()
j+/EG^*/ };
r
z@%rOWV LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
;YQ6X> BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
Ue,eEer BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
QJkiu8r BOOL InitHotkey();
a04S&ezj BOOL UnInit();
1uA-!T*e> #endif
HP 3%CB r[kHVT8 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Ud>hDOJ3 #include "stdafx.h"
1ATH$x #include "hook.h"
4T&Jlu?: #include <windowsx.h>
[vY)y\W{ #ifdef _DEBUG
ko!aX;K #define new DEBUG_NEW
M5`m5qc3 #undef THIS_FILE
436SIh static char THIS_FILE[] = __FILE__;
cY~lDLyB #endif
>i61+uzEd+ #define MAX_KEY 100
Cd p_niF #define CTRLBIT 0x04
,<OS:] #define ALTBIT 0x02
hiR+cPSF #define SHIFTBIT 0x01
b_~KtMO #pragma data_seg("shareddata")
=PLy^% HHOOK hHook =NULL;
g8"{smP/ UINT nHookCount =0;
}zeKf/?' static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
)5;|mV static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
;%u)~3B$JK static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
W"xRf0\V static int KeyCount =0;
6ESS>I"su static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
Pc~)4>X< #pragma data_seg()
Qej<(:J5 HINSTANCE hins;
,Qe`(vU*s void VerifyWindow();
Gn10)Uf8X BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
dUceZmAl //{{AFX_MSG_MAP(CHookApp)
aMJ9U)wnK // NOTE - the ClassWizard will add and remove mapping macros here.
FEA/}*2F // DO NOT EDIT what you see in these blocks of generated code!
oX/#Mct{s //}}AFX_MSG_MAP
.M\0+,%/ END_MESSAGE_MAP()
! -gOqo N9f;X{ CHookApp::CHookApp()
}
/Iw]!lK2 {
QO,ge<N+N // TODO: add construction code here,
qRZLv7X*j // Place all significant initialization in InitInstance
0j'k%R[l }
a>nV!b\n5 jB d9
$` CHookApp theApp;
)#cGePA LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
n ZS*"O#L {
j%*<W> O BOOL bProcessed=FALSE;
2 BwpxV8 if(HC_ACTION==nCode)
TUO#6 {
GwlAEh P if((lParam&0xc0000000)==0xc0000000){// Key up
s8kkf5bu switch(wParam)
0`e- ; {
X_I.f6v{ case VK_MENU:
W&a<Q)o*I MaskBits&=~ALTBIT;
Hn(L0#Oqy break;
W;wu2 ' case VK_CONTROL:
+wr
5& MaskBits&=~CTRLBIT;
_$4vk break;
V6
,59 case VK_SHIFT:
JE+{Vx} MaskBits&=~SHIFTBIT;
}Rq-IRa' break;
^S`c-N default: //judge the key and send message
b;sjw5cm_ break;
$;+`sVG }
<^jW for(int index=0;index<MAX_KEY;index++){
@AkD-}^[ if(hCallWnd[index]==NULL)
I#hzU8Cc continue;
;;- I<TL if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
~x}=lK N {
&+t,fwlM SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
"Mmvf'N bProcessed=TRUE;
Y3I+TI>x }
%7rWebd- }
)Ikx0vDFQ }
Ow]c,F}^ else if((lParam&0xc000ffff)==1){ //Key down
Lv
,Ls switch(wParam)
Tp/+{|~ {
enT.9|vm/ case VK_MENU:
n.Q?@\}2 MaskBits|=ALTBIT;
21U,! break;
L$FLQyDR case VK_CONTROL:
fKAG+ t MaskBits|=CTRLBIT;
O-vvFl#4 break;
vg1p{^N! case VK_SHIFT:
"I]% aK0 MaskBits|=SHIFTBIT;
!Hr
+|HKQ? break;
# 1,(I default: //judge the key and send message
hU `H\LE break;
&sQtS }
=lG5Kc{B for(int index=0;index<MAX_KEY;index++)
ef!V EtEOv {
-K)P|'-?m if(hCallWnd[index]==NULL)
PTvP; continue;
N|h}'p if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
E$rn^keM {
L+s,,k SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
#sEbu^ bProcessed=TRUE;
4>Q6!" }
/\_ s }
sT3O_20{ }
h^bbU. if(!bProcessed){
Qp${/ for(int index=0;index<MAX_KEY;index++){
PhM3?$ if(hCallWnd[index]==NULL)
Jh[fFg] continue;
u*&wMR>Crf if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
[N925?--S SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
I"9S }
r!etj3 }
[3rvRJ. }
jzu1>*ok return CallNextHookEx( hHook, nCode, wParam, lParam );
y:Qo:Z~ }
(_E<? ?E2/
CM BOOL InitHotkey()
vh+IhGi {
5"6Y=AuQ6 if(hHook!=NULL){
aBT|Q@Y. nHookCount++;
-mG3#88* return TRUE;
icHc!m? }
+X0?bVT else
cyG3le& +G hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
hn-9l1~!h if(hHook!=NULL)
Bi)1* nHookCount++;
+dk}$w[g return (hHook!=NULL);
x2[A(O= }
ep Eg6
BOOL UnInit()
aDTNr/I {
4lE
j/#} if(nHookCount>1){
W :jC2,s!m nHookCount--;
%X
O97 return TRUE;
">lu8F }
=zt@*o{F BOOL unhooked = UnhookWindowsHookEx(hHook);
p0UR5A>p if(unhooked==TRUE){
+hRAU@RA nHookCount=0;
Lt.a@\J'_ hHook=NULL;
&mKtW$K` q }
iXMs*GcK return unhooked;
4WZ:zr N }
try'%0}> 'q8T*|/ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
} O8|_d {
A$Mmnu% BOOL bAdded=FALSE;
M;,Q8z% for(int index=0;index<MAX_KEY;index++){
S
v$%-x^t if(hCallWnd[index]==0){
^i2W=A'P hCallWnd[index]=hWnd;
b'4{l[3~nl HotKey[index]=cKey;
%vDN{%h8 HotKeyMask[index]=cMask;
9H$#c_zrq bAdded=TRUE;
Dx/BxqG6}_ KeyCount++;
Q-_&5/G break;
[84ss;.$ }
&p%0cjg"Q }
%Iw6oG return bAdded;
;z/Z(7<;; }
Lqb9gUJ:U @-Tt<pl'L BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
LWuciHfd+ {
0qqk:h BOOL bRemoved=FALSE;
bf|s=,D for(int index=0;index<MAX_KEY;index++){
t23uQR#>b_ if(hCallWnd[index]==hWnd){
[QEV6S] if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
_SC{nZ[ hCallWnd[index]=NULL;
OOn{Wp HotKey[index]=0;
;fw}<M!6 HotKeyMask[index]=0;
E*'sk bRemoved=TRUE;
HjAhz KeyCount--;
dE~]%fUFy- break;
GKTt!MK }
#$2{l,> }
Jd?N5. }
e`9d&" return bRemoved;
(3~h)vaJ }
$5N %! )voJq\Y)% void VerifyWindow()
jD1/`g% {
Ut.%=o;&[ for(int i=0;i<MAX_KEY;i++){
5]pvHc if(hCallWnd
!=NULL){ :}'5'oVG
if(!IsWindow(hCallWnd)){ h|qTMwPr
hCallWnd=NULL; X5@+M!`
HotKey=0; {o1vv+i
HotKeyMask=0; n@|5PI"bx
KeyCount--; .8Eh[yiln
} ""$vaqt
} }huj%Pnk)
} Rp.42v#ck
} s^f7w
2%4u/
BOOL CHookApp::InitInstance() QS7<7+
{ b9nTg
AFX_MANAGE_STATE(AfxGetStaticModuleState()); _L?MYkD
hins=AfxGetInstanceHandle(); >TI/W~M
InitHotkey(); )oqNQ'yZ
return CWinApp::InitInstance(); AXnRAW
} 6z`l}<q
jW]Q-
int CHookApp::ExitInstance() tb$I8T
{ zF:
:?L~
VerifyWindow(); Wo)$*?
UnInit(); U]/iPG&_
return CWinApp::ExitInstance(); xB5qX7*.
} r2ZSkP.
(\8IgQ{
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file TAL,(&[s
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) wrP3:!=
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ 2P35#QI[)
#if _MSC_VER > 1000 p1F{ v^
#pragma once _2Zc?*4
#endif // _MSC_VER > 1000 ,~Y[XazT
d1jg3{pwA
class CCaptureDlg : public CDialog oYx4+xH/
{ GJs{t1
E
// Construction ^8.s"4{
public: K<wg-JgA
BOOL bTray; ;t~Y>,
BOOL bRegistered; ZR]p7{8B
BOOL RegisterHotkey(); ,
wXixf2
UCHAR cKey; c1tM(]&
UCHAR cMask; o[I
s$j
void DeleteIcon(); ]ZR}Pm/CA
void AddIcon(); !w1acmo<_
UINT nCount; mX2X.ww(4
void SaveBmp(); q}PUwN6
CCaptureDlg(CWnd* pParent = NULL); // standard constructor w`GjQIA
// Dialog Data *epK17i=
//{{AFX_DATA(CCaptureDlg) y$Fk0s*>
enum { IDD = IDD_CAPTURE_DIALOG }; C>A} e6o
CComboBox m_Key; %OJ"@6A
BOOL m_bControl; F4NMq&_
BOOL m_bAlt; o,rK8x
BOOL m_bShift;
bV$g]->4e
CString m_Path; %)ri:Q q
CString m_Number; $~e55X'!+
//}}AFX_DATA aH7@:=B
// ClassWizard generated virtual function overrides qWU59:d^{
//{{AFX_VIRTUAL(CCaptureDlg) [jz@d\k$_
public: [_`<<!u>-
virtual BOOL PreTranslateMessage(MSG* pMsg); ! FVD_8
protected: Ip<