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:
?#^_yd|<
k=<,A'y-/ 一、实现方法
V@Z8t8 +'H_sMmi{ 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:
qJj;3{X2
t]Xdzy #pragma data_seg("shareddata")
wwS{V HHOOK hHook =NULL; //钩子句柄
;/W;M> ^ UINT nHookCount =0; //挂接的程序数目
(63_ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
FLO#!G static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
)k0P' zGb static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
*f:^6h static int KeyCount =0;
bmotR8d static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
&UUIiQm~ #pragma data_seg()
CUT D]:\ "SyAOOZ 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。
cjU*
c<j2wKz 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:
DKCPi 0 \FSkI0 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
|~bl%g8xP cKey,UCHAR cMask)
pq6}q($Rk {
KDW%*%! BOOL bAdded=FALSE;
s#ijpc>h for(int index=0;index<MAX_KEY;index++){
9cAb\5c| if(hCallWnd[index]==0){
,
e{kC hCallWnd[index]=hWnd;
c~(+#a HotKey[index]=cKey;
N %-Cp) HotKeyMask[index]=cMask;
\iAkF`OC bAdded=TRUE;
rLNo7i KeyCount++;
@<e+E"6 break;
]5lp.#EB
}
k+2~=# }
Z&%#,0>] return bAdded;
w4 <FC$ }
V?v,q'? $ //删除热键
C`3}7qi|C BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
2/qP:3) {
%^m6Q! BOOL bRemoved=FALSE;
&dZ-}.
af for(int index=0;index<MAX_KEY;index++){
>[=q9k if(hCallWnd[index]==hWnd){
,V!s w5_5m if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
cA1"Nek hCallWnd[index]=NULL;
ja}_u}: HotKey[index]=0;
4;_{* U- HotKeyMask[index]=0;
/E/J< bRemoved=TRUE;
etj8M
y6= KeyCount--;
;BqYhi break;
\X5{>nNh }
bo rt2k }
TmG$Cjf84 }
-:`$8/A| return bRemoved;
o&1ewE(O] }
'$W@I s)#FqB8 n4+l,~ DLL中的钩子函数如下:
/c~z(wv ]'=]=o~4 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
u~\u8X3 {
S1&mY'c BOOL bProcessed=FALSE;
dJM)~Ay- if(HC_ACTION==nCode)
ozF>2`K
} {
2&O!<C j if((lParam&0xc0000000)==0xc0000000){// 有键松开
&a% |L=FY switch(wParam)
@Hj5ZJ
3 {
1+RG@Cp case VK_MENU:
m5SJB]a/ MaskBits&=~ALTBIT;
7.$0LN/a!Z break;
pw*<tXH! case VK_CONTROL:
d0~F|j\# MaskBits&=~CTRLBIT;
`3^*K/K\ break;
nVV>;e[ case VK_SHIFT:
^4_)a0Kcm, MaskBits&=~SHIFTBIT;
Iodk1Y; break;
>6Y\CixN default: //judge the key and send message
O emi } break;
Z 9mY*}:U~ }
+M! f}=H
for(int index=0;index<MAX_KEY;index++){
q?g4**C if(hCallWnd[index]==NULL)
Ub*Gv(Pg continue;
zE5%l`@|o if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
9(DS"fgC {
$-m@cObw!. SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
-;cZW.< bProcessed=TRUE;
XtVx
H4q }
7A?~a_Ep }
1GKd*z }
[!p>Id
else if((lParam&0xc000ffff)==1){ //有键按下
#N_C|v/ switch(wParam)
cq+|fg~Yy {
LO<R<zz case VK_MENU:
@6 uB78U4O MaskBits|=ALTBIT;
xtYX}u break;
fEE[huG case VK_CONTROL:
L5!aLv# MaskBits|=CTRLBIT;
R9nW5f
Nf break;
-hw^3Af case VK_SHIFT:
}YWLXxb; MaskBits|=SHIFTBIT;
?Z=
%I$i break;
7J,j default: //judge the key and send message
I}Uj"m`> break;
ED&>~~k) }
SYRr|Lg for(int index=0;index<MAX_KEY;index++){
Ql^I$5& if(hCallWnd[index]==NULL)
FuiG=quY continue;
Hj't.lg+j if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
wl H6 {
yEyx.Mh.Af SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
13wO6tS
k bProcessed=TRUE;
[ZU6z?Pf }
]3]I`e{ }
=mxG[zDtQ }
XQ]no aU if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
#4iSQ$0 for(int index=0;index<MAX_KEY;index++){
>%5Ld`c:SD if(hCallWnd[index]==NULL)
awh<CmcZ continue;
9HrT>{@ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
;X,|I) SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
{J;[
Hf5 //lParam的意义可看MSDN中WM_KEYDOWN部分
x9q?^\x }
V/"UDof }
^.)oQo SE }
F8mS5oB|^
return CallNextHookEx( hHook, nCode, wParam, lParam );
p;cNmMm }
:,%~R2 $(B|$e^:( 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:
^N#B(F \=PnC}7I BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
}M-^A{C\% BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
#'[4k: =aZgq99 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:
N,fEta6 &7_xr.c7 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
/ r6^]grg {
#&<>|m if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
%^tKt {
wb~BY //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
b>SG5EqU@ SaveBmp();
l =~EweuM return FALSE;
5<ZE.'O }
&{E1w<uv …… //其它处理及默认处理
koDIxj'%X }
x6Zhw9RV 1"tyxAo\ Pj(DlC7G, 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。
ChzKwYDY OQ>8Q` 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。
Z$
q{!aY `&y Qtj#
' 二、编程步骤
BUB$k7{z #4UKkd 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
& -L$B
k|V%*BvY> 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
Nki08qZ[ =hD@hQi 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;
:Z)a&A9v r,I';vm<` 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;
2$ m#)*\
%f3qCN 5、 添加代码,编译运行程序。
!YX$4_I Ok63 w7 三、程序代码
qj|P0N{7 ou8V7 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
F[am2[/<A #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
NMJX ` #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
w]<V~X #if _MSC_VER > 1000
V$wW?+V #pragma once
2OT
RP4U #endif // _MSC_VER > 1000
CVUA7eG+ #ifndef __AFXWIN_H__
L_4c~4 #error include 'stdafx.h' before including this file for PCH
; '6`hZ #endif
WEy$SN+P #include "resource.h" // main symbols
9O(vh(C class CHookApp : public CWinApp
0Va+l)F {
ZAATV+Z public:
(j<FS>## CHookApp();
].ZfTrM] // Overrides
3XykIj1 // ClassWizard generated virtual function overrides
=Q+i(UGHi //{{AFX_VIRTUAL(CHookApp)
Hwb+@'o public:
1M@OBfB8 virtual BOOL InitInstance();
WXq=FZ- virtual int ExitInstance();
FTu6%~M/ //}}AFX_VIRTUAL
&.W,Hh //{{AFX_MSG(CHookApp)
>}~\*Y\8@ // NOTE - the ClassWizard will add and remove member functions here.
!fX&i 6 // DO NOT EDIT what you see in these blocks of generated code !
>-S? rXO //}}AFX_MSG
/wAx#[c[ DECLARE_MESSAGE_MAP()
v9*ugu[K9 };
o,qq*}= LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
c_V^~hq BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
j8P qc] BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
CG#lpAs BOOL InitHotkey();
<O<Kf:i&c1 BOOL UnInit();
|h^[/ #endif
6ijL+5 stxei
6 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
h2S!< #include "stdafx.h"
TA4>12C6 #include "hook.h"
5:R$xgc #include <windowsx.h>
jpwR\"UJ #ifdef _DEBUG
;*{"|l qe #define new DEBUG_NEW
]S #undef THIS_FILE
gm^j8B static char THIS_FILE[] = __FILE__;
8NF93tqD6 #endif
7C;oMh5 #define MAX_KEY 100
@ra^0 #define CTRLBIT 0x04
srbES6 #define ALTBIT 0x02
hZZ #define SHIFTBIT 0x01
R!)3{cjU@ #pragma data_seg("shareddata")
T 6ihEb$C HHOOK hHook =NULL;
^Uq%-a UINT nHookCount =0;
mV>l`&K= static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
we("#s1= static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
{{:QtkN static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
9-/u _$ static int KeyCount =0;
s78MXS?py static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
/]1$Soo #pragma data_seg()
^5'pJ/BV HINSTANCE hins;
gPE`mE void VerifyWindow();
uqotVil, BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
nsA}A~(E //{{AFX_MSG_MAP(CHookApp)
jT'09r3P // NOTE - the ClassWizard will add and remove mapping macros here.
!V^wq]D2 // DO NOT EDIT what you see in these blocks of generated code!
4 EE7gkM5 //}}AFX_MSG_MAP
Tv[|^G9x END_MESSAGE_MAP()
A4~-{.w= |l-~,eRvi5 CHookApp::CHookApp()
8NZQTRdH {
J#'8]p3E // TODO: add construction code here,
vZiuElxKi // Place all significant initialization in InitInstance
K0aT(Rc
e }
:kMF.9U: W(jOD,QMB CHookApp theApp;
ikd1KF+I LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
1agNwFd~ {
)5[OG7/g BOOL bProcessed=FALSE;
yR3pK
0Y(? if(HC_ACTION==nCode)
mOC<a7# {
oBS m>V if((lParam&0xc0000000)==0xc0000000){// Key up
p3,m), switch(wParam)
Hk8lHja+\ {
JW},7Ox case VK_MENU:
?S<`*O
+ MaskBits&=~ALTBIT;
`VrQ?s break;
RW`j^q,c3 case VK_CONTROL:
FoQy@GnM5 MaskBits&=~CTRLBIT;
d=nv61] break;
9oU1IT9 case VK_SHIFT:
('~}$%C MaskBits&=~SHIFTBIT;
Yycfb break;
V/&JArW default: //judge the key and send message
]*Cq'<h$ break;
'" 4;;( }
rRvZG&k
for(int index=0;index<MAX_KEY;index++){
`Sx1?@8( if(hCallWnd[index]==NULL)
=OeLF continue;
ID]E3K if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
vbh 5 {
L9$`zc SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
[xdi.6% bProcessed=TRUE;
|}o6N5) }
cx~XG }
~@\sN+VS }
|SfCuV#g/< else if((lParam&0xc000ffff)==1){ //Key down
7_Op(C4,nC switch(wParam)
4 KX\'K {
4aiI&, case VK_MENU:
w{WEYS MaskBits|=ALTBIT;
,hOi5,|?L break;
ElA(1o|9I case VK_CONTROL:
$(]E$ek MaskBits|=CTRLBIT;
5S*aZ1t18 break;
5m
yQBKE case VK_SHIFT:
MW2{w<-]7 MaskBits|=SHIFTBIT;
r>ag(^J\ break;
=[:pm) default: //judge the key and send message
iv
~<me0F break;
7O-fc1OTv }
m%cwhH_B for(int index=0;index<MAX_KEY;index++)
FL{$9o\@ {
| Rj"}SC if(hCallWnd[index]==NULL)
+a"f)4\ continue;
O+?vQ$z if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
w|1O-k` {
Mi} . SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
n%6ba77 bProcessed=TRUE;
4-?zW }
^kK% 8 u }
OH 13@k }
||))gI`3a if(!bProcessed){
#}lWM%9Dy for(int index=0;index<MAX_KEY;index++){
<Gna}ALkg if(hCallWnd[index]==NULL)
z22:O"UHa continue;
h])oo:u'/Q if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
-%dBZW\u2 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
DB+oCE<.# }
bao"iv~z }
FeNNzV= }
w$Z%RF'p return CallNextHookEx( hHook, nCode, wParam, lParam );
=gB8(1g8 }
>9NC2%61S "&/lF[q BOOL InitHotkey()
r=/$}l4 {
iS< ^MD if(hHook!=NULL){
"Hk7s+% nHookCount++;
@qSZ= return TRUE;
/E!N:g< }
7h.fT` else
{DapXx hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
q8!]x-5$6j if(hHook!=NULL)
`pjB^--w nHookCount++;
p<<dj% return (hHook!=NULL);
#;=sJ[m4 }
[tR b{JsUd BOOL UnInit()
~RH)iI {
PQ{5*}$N if(nHookCount>1){
Ciy%7_~\ nHookCount--;
q+} \(| return TRUE;
\&l@rMD3s }
B3<sSe8L0 BOOL unhooked = UnhookWindowsHookEx(hHook);
~e&O?X if(unhooked==TRUE){
4peRbm nHookCount=0;
/Pxny3 hHook=NULL;
`2/V.REX$h }
yJ="dEn>i" return unhooked;
dQz#&&s-
}
[FZq'E"87 TPs
]n7]: BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
,M~> t7+ {
_'4S1 BOOL bAdded=FALSE;
phQ{<wzwp for(int index=0;index<MAX_KEY;index++){
s\< @v7A if(hCallWnd[index]==0){
FKPR;H8> hCallWnd[index]=hWnd;
*I[tIO\ HotKey[index]=cKey;
&;sW4jnt HotKeyMask[index]=cMask;
4bcd=a; bAdded=TRUE;
!L@<?0xLW KeyCount++;
o70] F break;
==BOW\ }
yzMGZi`ut }
fwiP3*j+Nn return bAdded;
K { FZ/ }
|+KwyHE`9 ?\)h2oi!F5 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
~N2=44e {
t
.}];IJP BOOL bRemoved=FALSE;
~ToU._ for(int index=0;index<MAX_KEY;index++){
do*aE if(hCallWnd[index]==hWnd){
<k0/O if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
p I~;3T:! hCallWnd[index]=NULL;
G8 q<) HotKey[index]=0;
Uu52uR HotKeyMask[index]=0;
M[+#*f.T} bRemoved=TRUE;
Yep~C%/} KeyCount--;
jSSEfy>^ break;
'F#dv[N }
B*Ey&DAV }
Rt:^'Qi$! }
];jp)P2o return bRemoved;
O"/Sv'|H# }
,p#r; O<O o@7U4#E void VerifyWindow()
c%bzrYQvA; {
!{ {gL=_@ for(int i=0;i<MAX_KEY;i++){
CxNxb)c & if(hCallWnd
!=NULL){ pp@B]We
if(!IsWindow(hCallWnd)){ rLE+t(x(0
hCallWnd=NULL; ##}7cFX
HotKey=0; A2;6Vz=z
HotKeyMask=0; ?;H}5>^8P
KeyCount--; Pjn{3/*wi
} j@w1S[vt
} :`Ep#[Wvo
} d S'J @e=#
} nM Z)x-
qGX#(,E9;
BOOL CHookApp::InitInstance() +jK-k_
{ IibYG F
AFX_MANAGE_STATE(AfxGetStaticModuleState()); H
cyoNY
hins=AfxGetInstanceHandle(); [qC0YM
InitHotkey(); Nd+1r|e'
return CWinApp::InitInstance(); GKjtX?~1
} x$bUd 9
aL`wz !
int CHookApp::ExitInstance() "<{|ni}
{ ,p OGT71
VerifyWindow(); 3Pllxq<n
UnInit(); hF$qH^-c*A
return CWinApp::ExitInstance(); <hj2'dU
} }r! +wp
t=xEUOQAn
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file qTN%9!0@9
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 9(nq 4HvI
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ cs?WE9N
#if _MSC_VER > 1000 k& +gkJm
#pragma once _ziSH 3(
#endif // _MSC_VER > 1000 .c~z^6x
D/~1?p
class CCaptureDlg : public CDialog vy 7/
{ P tLWFO
// Construction AFm9"mQrw
public: \D(3~y>
BOOL bTray; ajtH1Z#
BOOL bRegistered; zTjie
BOOL RegisterHotkey(); q\x.e.@
UCHAR cKey; =4co$oD}
UCHAR cMask; |/^S%t6*
void DeleteIcon(); gBi3^GxjM?
void AddIcon(); 9Li*L&B)
UINT nCount; =>B"j`oR
void SaveBmp(); w$AR
CCaptureDlg(CWnd* pParent = NULL); // standard constructor Eu:/U*j
// Dialog Data -4sKB>b
//{{AFX_DATA(CCaptureDlg) ux)*B}/xh
enum { IDD = IDD_CAPTURE_DIALOG }; M?UUT8,
CComboBox m_Key; 'j<u0'K@
BOOL m_bControl; ]X77?Zz9
BOOL m_bAlt; N0-J=2
BOOL m_bShift; N0Y4m_dm*
CString m_Path; y.J>}[\&x
CString m_Number; }8#Ed;%K
//}}AFX_DATA Ie!&FQe2