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:
B^fT>1P
?
-3\ 一、实现方法
fW?sYC' ~,"N[Q 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:
B8T\s)fxnX +4et7 #pragma data_seg("shareddata")
$&hN*7Ts HHOOK hHook =NULL; //钩子句柄
p3c"ZPO~z UINT nHookCount =0; //挂接的程序数目
%r%So_^ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Qzqc .T static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
a+`D'?z static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
BkawL, static int KeyCount =0;
3JO]f5 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
}aF #pragma data_seg()
*5k+t wv?RO*E 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
BcQEG *N h}Rx_d DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
i?>tgmu. ~.^AL}zm_ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
?cKZ_c cKey,UCHAR cMask)
VWx]1\ {
xzsdG?P BOOL bAdded=FALSE;
IA4N@ijRxh for(int index=0;index<MAX_KEY;index++){
/c` ^iPb if(hCallWnd[index]==0){
1l5JP|x hCallWnd[index]=hWnd;
7]Em, HotKey[index]=cKey;
s"%lFA"- HotKeyMask[index]=cMask;
bFY~oa%C bAdded=TRUE;
ba3*]01Yb KeyCount++;
LY 0]l$ break;
,\YAnKn6_ }
mM_
k^4: }
w##^}nHOR return bAdded;
nirDMw[ }
A#rh@8h+ //删除热键
fE]XWA4U BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Zd!U')5/ {
=Mj0:rW BOOL bRemoved=FALSE;
=dZHYO^Cv for(int index=0;index<MAX_KEY;index++){
***a2Z/( if(hCallWnd[index]==hWnd){
uo2'"@[e if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
! zL1;d hCallWnd[index]=NULL;
aS84n.?vq HotKey[index]=0;
Io n~ HotKeyMask[index]=0;
NBYH;h P bRemoved=TRUE;
X(@uw X$m KeyCount--;
-MBV$:_R break;
4;<ut$G }
Dnw| %6Y }
Fh8lmOL;? }
8R/dA<Ww return bRemoved;
3BG>Y(v }
E{?au]y$J *bd[S0l $,3J7l3 DLL中的钩子函数如下:
= &tmP -C-yQ.>\T# LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
)Ry<a$Q3 {
B07v^!Z> BOOL bProcessed=FALSE;
]p7jhd= if(HC_ACTION==nCode)
`d\r;cE%lm {
'n;OB4 if((lParam&0xc0000000)==0xc0000000){// 有键松开
:|+Qe e switch(wParam)
Qm4o7x{q {
1oiRW Re case VK_MENU:
P 43P]M2 MaskBits&=~ALTBIT;
jYRP8 Yi break;
n]}W``=7 case VK_CONTROL:
piy`zc-yu MaskBits&=~CTRLBIT;
Fv74bC% break;
rG}\Zjn{ case VK_SHIFT:
r [ : MaskBits&=~SHIFTBIT;
EV pi^>M break;
3"N)xO- default: //judge the key and send message
?e[lr>- break;
m_+sR!\H8 }
ntFT>g{B for(int index=0;index<MAX_KEY;index++){
H@bf'guA|B if(hCallWnd[index]==NULL)
p]T<HGJ P continue;
1y#D?R=E if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
$+p?Y)h . {
#>lG7Ns|4 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
':{>a28= bProcessed=TRUE;
Ae]sGU|?' }
7x);x/#8Z }
%D$]VSP; }
i4Lc$20?d else if((lParam&0xc000ffff)==1){ //有键按下
AIMSX]m switch(wParam)
I9h ?;( {
|L2SFB?d= case VK_MENU:
y!tC20Q MaskBits|=ALTBIT;
CI353-` break;
%\]*OZ7 case VK_CONTROL:
*Kdda}
J+ MaskBits|=CTRLBIT;
*na?n2Yzt break;
<sK4#!K case VK_SHIFT:
Mmpfto%i MaskBits|=SHIFTBIT;
}PTV] q% break;
hxQqa 0B default: //judge the key and send message
_SW3_8SuM. break;
BauU{:Sh }
C8
\5A8c for(int index=0;index<MAX_KEY;index++){
M5gWD==uP if(hCallWnd[index]==NULL)
:#@ = B] continue;
7}M2bH} \K if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
O
T.*pk+<) {
$Y69@s %f SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
;)N>t\v bProcessed=TRUE;
wF(( }
EoK~S\dS }
'!/<P"5t }
KQB3m" if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
UQ{L{H for(int index=0;index<MAX_KEY;index++){
Z&;uh_EC if(hCallWnd[index]==NULL)
vZ.x{"n'~ continue;
[Xb@Wh:yG if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
9eH$XYy SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
u ~A6bK* //lParam的意义可看MSDN中WM_KEYDOWN部分
BNL;Biyt7 }
uEX!xx?Q# }
g$b<1:8 }
dC RyOid$ return CallNextHookEx( hHook, nCode, wParam, lParam );
/~zai} }
8F._9U-EN &Z`#cMR{H 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:
hCC<?5q #B4%|v;`E? BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
+E{|63~q BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
'&\kxNglJ \[y`'OD~ 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:
~]QHk?[wc /5u<78GW1 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
4O35"1 {
=3L;Z[^9 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
x QIq^/F0 {
2 B //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
p6;OL@\~ SaveBmp();
,^C--tgZJg return FALSE;
ZzSz%z_sE }
8uWa=C) …… //其它处理及默认处理
97}OL`y }
"'t0h{Wr8 .>WxDQIo C#Na&m 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。
; #&yn=^ XT4{Pe7{[P 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。
(L/_^!ZX O6LS(5j2 二、编程步骤
"vOwd.(?N LU={")TdQ 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";
]"?)Z @0/+_2MH- 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
PK `D8)=u t+!$[K0/ 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
JsODzw ^zQ/mo,Z 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
8|\8O@ a6uJYhS~ 5、 添加代码,编译运行程序。
xCc[#0R{ fTK3,s1= 三、程序代码
/w}u3|L$ t:'Mh9h7u ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
wY[+ZT #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
NU5.o$
#define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
OG>}M$Ora #if _MSC_VER > 1000
w|K'M?N14 #pragma once
4bYK}oS #endif // _MSC_VER > 1000
,Ge"anO #ifndef __AFXWIN_H__
z?R|Ok #error include 'stdafx.h' before including this file for PCH
!WQ-=0cm #endif
oYm[V<nIl #include "resource.h" // main symbols
nH[yJGZYSA class CHookApp : public CWinApp
pSdI/Vj'= {
@eKec1< public:
ddJe=PUb CHookApp();
/7Cc#P6 // Overrides
K3#@SYj // ClassWizard generated virtual function overrides
#ML%ij 1 //{{AFX_VIRTUAL(CHookApp)
]H+8rY%+ public:
n<z[J=I virtual BOOL InitInstance();
4\8+9b\9" virtual int ExitInstance();
1cpiHZa //}}AFX_VIRTUAL
!ug8SAOaz/ //{{AFX_MSG(CHookApp)
d,B:kE0Y // NOTE - the ClassWizard will add and remove member functions here.
sN9&,&W1 // DO NOT EDIT what you see in these blocks of generated code !
BHU6t<G
//}}AFX_MSG
KUlp"{a`,K DECLARE_MESSAGE_MAP()
3sy (vC };
;;6uw\6
O LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
!Fd~~v BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
RAgg:3^ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
C26>BU< BOOL InitHotkey();
3u*4o=4e BOOL UnInit();
\o*5 #endif
)<h*eS{ 'h|DO/X~L //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
P2#XKG #include "stdafx.h"
K8GP@yD]M #include "hook.h"
nxnv,AZG #include <windowsx.h>
W{6|tx) #ifdef _DEBUG
Y5- F@( #define new DEBUG_NEW
$5aV:Z3P #undef THIS_FILE
z[L8$7L static char THIS_FILE[] = __FILE__;
!Prg_6
` #endif
v$?+MNks #define MAX_KEY 100
|
*2w5iR #define CTRLBIT 0x04
1WxK#c-) #define ALTBIT 0x02
$P/~rZ@M@ #define SHIFTBIT 0x01
Vc\MV0lr #pragma data_seg("shareddata")
rWa2pO HHOOK hHook =NULL;
!Qu"BF UINT nHookCount =0;
9PXFRxGA static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
-#u=\8 static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
%)zodf static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
r!_-"~`7E static int KeyCount =0;
CQF:Rnb static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
5Ha9lM2gh #pragma data_seg()
5q3JI HINSTANCE hins;
gmw|H?] void VerifyWindow();
cQCSe,$ W BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
G|!Tj X7s //{{AFX_MSG_MAP(CHookApp)
|"ls\ 7 // NOTE - the ClassWizard will add and remove mapping macros here.
Yvw(tj5_5 // DO NOT EDIT what you see in these blocks of generated code!
ayR-\mZ //}}AFX_MSG_MAP
&^ 1$^= END_MESSAGE_MAP()
+"
.X
)avF !Xf5e*1IS CHookApp::CHookApp()
`u3EU*~W {
BC&S> #\ // TODO: add construction code here,
N{9v1`B // Place all significant initialization in InitInstance
gc_:%ki }
il4^zj82 #+ 0M2Sa CHookApp theApp;
yVU^M?`# LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
]!?;@$wx {
e^6)Zz1\ BOOL bProcessed=FALSE;
<wN}X#M if(HC_ACTION==nCode)
Y,<{vLEC {
]7W&JKmA& if((lParam&0xc0000000)==0xc0000000){// Key up
:~&~y-14 switch(wParam)
FH?U(- {
\)#kquH/l case VK_MENU:
1H?
u Qy MaskBits&=~ALTBIT;
?~BC#B\>o break;
Gw/Pk4R case VK_CONTROL:
S 6@u@C MaskBits&=~CTRLBIT;
4KhV|#-;k break;
i1ixi\P{0 case VK_SHIFT:
6tgt>\y MaskBits&=~SHIFTBIT;
-`*a'p-= break;
:%tU'w default: //judge the key and send message
?pW`cFLDHF break;
GZN ^k+w }
eVjBGJ=2e for(int index=0;index<MAX_KEY;index++){
<=zQ NBtx if(hCallWnd[index]==NULL)
n\Z!ff/ continue;
_<n~n]% if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
ZCMw3]* {
w1EXh SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
-;s| bProcessed=TRUE;
xI #9 }
!#], hok8X }
oR)Jznmi} }
@Q)OGjaq else if((lParam&0xc000ffff)==1){ //Key down
@'#,D!U switch(wParam)
U dT*E: 6 {
%a>&5V case VK_MENU:
Si2k"<5U MaskBits|=ALTBIT;
@>r._~ break;
>c1qpk/ case VK_CONTROL:
`x+ B+)0X MaskBits|=CTRLBIT;
[%"|G9 break;
|GdUL%1hnC case VK_SHIFT:
n,vct<&z@ MaskBits|=SHIFTBIT;
xK *b1CB break;
Qf~vZtJ+J default: //judge the key and send message
~Z\8UsVN break;
c,np2myd }
sJB;3"~ for(int index=0;index<MAX_KEY;index++)
:KQ~Cb {
I:R[;TB?y if(hCallWnd[index]==NULL)
?ZV/U!y continue;
6KXtcXQ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
/hr7NT{e%v {
hQ,ch[j' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
RuLi,'u bProcessed=TRUE;
ity & v9 }
<T` 7%$/E }
($q-_m }
"Gsc;X'id if(!bProcessed){
*>Ns_su7W for(int index=0;index<MAX_KEY;index++){
i?p$H0bn if(hCallWnd[index]==NULL)
|kyX3~ continue;
~8q)^vm>f? if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
[+rfAW>p} SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
F|SXn\ }
dPW#C5dm }
tqz3zIQ }
3+)J
@(a return CallNextHookEx( hHook, nCode, wParam, lParam );
3]5^r} }
#3i3G(mQ [;n9:Qxf BOOL InitHotkey()
+F R0(T {
H*d9l2,KZS if(hHook!=NULL){
Mo|;'+ nHookCount++;
k0OYJ/ return TRUE;
=:xW>@bh| }
L7n D| else
L O}@dL hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
f}o\*|k_| if(hHook!=NULL)
td(li., nHookCount++;
>~''&vdsk\ return (hHook!=NULL);
z6KCv(zvB }
:y'Ah# BOOL UnInit()
v"y-0$M {
A!od9W6 if(nHookCount>1){
52@C9Q, nHookCount--;
]i|h(>QWP return TRUE;
cq,S P&T~ }
+^` I?1\UF BOOL unhooked = UnhookWindowsHookEx(hHook);
QE^$=\l0 if(unhooked==TRUE){
3lf=b~Zi) nHookCount=0;
Zd3S:),& hHook=NULL;
2Z+Wu3# }
|6.l7u?d return unhooked;
p2hB8zL }
=mO vs GA$V0YQX BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
`LrHKb
aP {
bBiE BOOL bAdded=FALSE;
JgxtlYjl for(int index=0;index<MAX_KEY;index++){
\Z?9{J if(hCallWnd[index]==0){
R|6Cv3: hCallWnd[index]=hWnd;
M92dZ1+6 HotKey[index]=cKey;
tZ]?^_Y1 HotKeyMask[index]=cMask;
/
kF) bAdded=TRUE;
8V~k5#&Ow KeyCount++;
P@,XEQRd` break;
4-l8,@9 }
.N,bIQnj }
57'*w]4f return bAdded;
BGvre'67 }
FI)17i$
[@&m4 7 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
%vn|k[nD {
'f#{{KA BOOL bRemoved=FALSE;
g?c
xp+ for(int index=0;index<MAX_KEY;index++){
NN%*b yK if(hCallWnd[index]==hWnd){
h){0rX@:& if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
@D]5c ivm_ hCallWnd[index]=NULL;
^ sOQi6pL HotKey[index]=0;
=J18eH!] HotKeyMask[index]=0;
E~DQ-z bRemoved=TRUE;
uu-PJTNZ KeyCount--;
-"R2 break;
?j'7l=94A }
;!>rnxB?4 }
J!AgBF N4 }
I&fozO
return bRemoved;
U&g@.,Y# }
$POu\TO 9>=;FY void VerifyWindow()
B~'vCuE {
j%Y#(Q> for(int i=0;i<MAX_KEY;i++){
034iK[ib" if(hCallWnd
!=NULL){ |T<_ 5Ik
if(!IsWindow(hCallWnd)){ c/:b.>W
hCallWnd=NULL; )Oq|amvC
HotKey=0; 7LfAaj
HotKeyMask=0; ;@0;pY
KeyCount--; `Syl:rU~y@
} Mc?Qx
} ^a/gBC82x
} ]MqMQLG0t
} OsTc5K.U~
(j%~u&+-
BOOL CHookApp::InitInstance() R6 y#S&]x
{ ^+*N%yr
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 5 )A1\
hins=AfxGetInstanceHandle(); *1ilkmL%
InitHotkey(); >,v`EIg
return CWinApp::InitInstance(); eln)BW#
} HSw;^E)1
2% MC Yn
int CHookApp::ExitInstance() im${3 >26
{
YC*"Thuu
VerifyWindow(); lz/8
UnInit(); =h-U
return CWinApp::ExitInstance(); t0( A4E
} N&.H|5
`:ArT}F
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file $r^GE
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) On8v//=&
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ "x#-sZ=
#if _MSC_VER > 1000 O+nEXS\rQ
#pragma once <!&[4-;fU
#endif // _MSC_VER > 1000 HNb/-e ,"
S%$ }(
class CCaptureDlg : public CDialog ^8]NxV@l
{ )~&CvJ
// Construction 9d>-MX'
public: ]N/=Dd+|
BOOL bTray; -5)H<dAQZ
BOOL bRegistered; %{7|1>8
BOOL RegisterHotkey(); >d(~#Z`
UCHAR cKey; EW}Bz h>b
UCHAR cMask; ##q2mm:a9P
void DeleteIcon(); q?Cnav`DY
void AddIcon(); gK+4C
UINT nCount; @Y?#Sl*
void SaveBmp(); e-~N"
CCaptureDlg(CWnd* pParent = NULL); // standard constructor _H9 MwJ
// Dialog Data *o]L|Vu
//{{AFX_DATA(CCaptureDlg) >;jZa
enum { IDD = IDD_CAPTURE_DIALOG }; 3(``#7
CComboBox m_Key; `b?R#:G
BOOL m_bControl; Av$]|b
BOOL m_bAlt; Vk`h2BV
BOOL m_bShift; mJ<=n?{Z
CString m_Path; Qu"8(Jk/
CString m_Number; S\^Pha
q
//}}AFX_DATA |e=,oV"
// ClassWizard generated virtual function overrides a y4 %
//{{AFX_VIRTUAL(CCaptureDlg) \Yy$MLs
public: ['b}QW@Fx
virtual BOOL PreTranslateMessage(MSG* pMsg); Z/G
ev"p
protected: w3N[9w?1
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support 0}<