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:
kp<Au)u
,]: <l 一、实现方法
,tg]Gt F!u)8>s+z{ 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:
|nnFjGC`~ UF-'( #pragma data_seg("shareddata")
PI`Y%! P HHOOK hHook =NULL; //钩子句柄
_b-g^#L% UINT nHookCount =0; //挂接的程序数目
eZ[Qhrc static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
r2'K'?T3 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
w@Q~ax/ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
l1]{r2g static int KeyCount =0;
<\Y(+?+uZ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
41Q)w=hoN #pragma data_seg()
hHVAN3e \$DBtq5= 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。
71P. 9Iz KA{QGaZ/ 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:
wXqwb|2 I ZLCwaW BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
/.!&d^ cKey,UCHAR cMask)
ILH[q> {
WTl0}wi BOOL bAdded=FALSE;
e],(d7 Jo for(int index=0;index<MAX_KEY;index++){
sn^ 3xAF if(hCallWnd[index]==0){
=1R
2`H\ hCallWnd[index]=hWnd;
2YWO'PL HotKey[index]=cKey;
>yT1oD0+x HotKeyMask[index]=cMask;
}wvR s5;o bAdded=TRUE;
g4Dck4^!4 KeyCount++;
H*3u]Ebh break;
-UzWLVB^ }
mrG?5.7W }
DO*6gzW return bAdded;
1pDU}rPJ. }
*dBmb //删除热键
y&8`NS#_p? BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
}93FWo. {
+,ar`:x&a BOOL bRemoved=FALSE;
d#bg(y\G| for(int index=0;index<MAX_KEY;index++){
S[/udA if(hCallWnd[index]==hWnd){
h@ ZC{B if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
*& );-r`. hCallWnd[index]=NULL;
mdrqX<x'~ HotKey[index]=0;
i(.PkYkaq HotKeyMask[index]=0;
S\t!7Xs%*U bRemoved=TRUE;
e<`?$tZ3
KeyCount--;
!J<0.nO/: break;
tq'hiS(b }
(]I=';\ }
r<srTHGLo }
s/11TgJ return bRemoved;
<GQ=PrT|/ }
G^K;+& T =1|p$@L`% 0~WXA=XG DLL中的钩子函数如下:
Q7v1xBM _G<Wq`0w) LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
`uusUw-Gf {
1?8M31 BOOL bProcessed=FALSE;
y,`0f| if(HC_ACTION==nCode)
T7/DH {
y<R5}F if((lParam&0xc0000000)==0xc0000000){// 有键松开
5i'?oXL switch(wParam)
Oz]$zRu/0 {
LqJV case VK_MENU:
7AGUi+!ICl MaskBits&=~ALTBIT;
gCkR$.-E break;
!m'Rp~t case VK_CONTROL:
Y@MxKK uj MaskBits&=~CTRLBIT;
UEYJd&n0CB break;
""N~##)8 case VK_SHIFT:
|{ZdAr.; MaskBits&=~SHIFTBIT;
FoZI0p?L)9 break;
c`lL&*] default: //judge the key and send message
Z]k@pR ! break;
RK$( }
Rd]<591 for(int index=0;index<MAX_KEY;index++){
Sz1 J4$5 if(hCallWnd[index]==NULL)
B^R44j]3" continue;
YG0b*QBY~ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
K g.O2F77 {
w6Mv%ZO_ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
TPKD'@:x bProcessed=TRUE;
l)jP!k }
{36N=A }
DZH2U+K }
JlRNJ#h> else if((lParam&0xc000ffff)==1){ //有键按下
{KEmGHC4R switch(wParam)
F1M:"-bda {
zq ?xY`E case VK_MENU:
cdSgb3B0 MaskBits|=ALTBIT;
[[';Hi^ break;
A>FWvlLw'm case VK_CONTROL:
r/P}j4)b7 MaskBits|=CTRLBIT;
7<B-2g break;
%AWc`D
case VK_SHIFT:
(#z6w#CU( MaskBits|=SHIFTBIT;
"i*gJFW| break;
#!#s7^%K& default: //judge the key and send message
0XqxW\8_l break;
%yl17:h# }
SdnO#J}{ for(int index=0;index<MAX_KEY;index++){
$
O[Y if(hCallWnd[index]==NULL)
"oF)u1_? continue;
Ra
H1aS( if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
!<~cjgdx {
jPZpJ: SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
w
$`w bProcessed=TRUE;
ga S}>?qk }
/Ah&d@b }
x5/&,&m`% }
rQ U6*f if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
'4Qsl~[Eh for(int index=0;index<MAX_KEY;index++){
` QW=<Le? if(hCallWnd[index]==NULL)
YB2gxZ continue;
gA@Zx%0j if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
T"gk^. SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
=1,1}OucP //lParam的意义可看MSDN中WM_KEYDOWN部分
%&V%=-O_7 }
&CN(PZv }
uaU2D-ft" }
K1]3zLnS return CallNextHookEx( hHook, nCode, wParam, lParam );
jcBZ#|B7; }
o[+t}hC[ MHye!T6fO\ 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
.sFN[>) ~#}T| BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
~(GNY5 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
v7`{6Pf_$ j F/S2Ty2 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:
!=a]Awr\ ~<s =yjTu+ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
G'(rjH>q {
9
Qa_3+.B if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
<1<xSr {
7\R"RH- //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
NuD|%Ebs SaveBmp();
fBv:
TC% return FALSE;
|d*a~T0 }
N#t`ZC&m' …… //其它处理及默认处理
woBx609Aak }
>V)"TZH JEMc _ngR! |5X[/Q*K`W 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。
mZPvG (j?? 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。
a'dlAda DZ\K7- 二、编程步骤
h0g?=hJq 4K?
\5(b 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";
=+ >>l0=_v .jk
A'i@ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
TO"Md["GI N
fG9a~ 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;
?# _{h =y)K er 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;
9:-7.^`P zp<B,Ls 5、 添加代码,编译运行程序。
voN~f> ZILJXX4 三、程序代码
!Hl] & 5Pn.c! ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
Ef28 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
qq)}GK8K& #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
&r4|WM/ec #if _MSC_VER > 1000
vB{iw}Hi! #pragma once
@p
WN5VL #endif // _MSC_VER > 1000
)Se$N6u- #ifndef __AFXWIN_H__
cy;i1#1rO #error include 'stdafx.h' before including this file for PCH
uW=G1 *n- #endif
]S[?tn #include "resource.h" // main symbols
-`* 'p i class CHookApp : public CWinApp
f(~N+2} {
wL="p) TO. public:
Mb 4"bDBsl CHookApp();
vIOGDI> // Overrides
=&$z
Nc4h // ClassWizard generated virtual function overrides
@*Ry`)T //{{AFX_VIRTUAL(CHookApp)
gK({InOP public:
}^&f { virtual BOOL InitInstance();
m:[I$b6AY virtual int ExitInstance();
5:f!EMb //}}AFX_VIRTUAL
Zp~yemERr //{{AFX_MSG(CHookApp)
mY4pvpZw8 // NOTE - the ClassWizard will add and remove member functions here.
Q+9:]Bt // DO NOT EDIT what you see in these blocks of generated code !
2[qfF6FHA //}}AFX_MSG
5}ftiy[Yc DECLARE_MESSAGE_MAP()
o9"?z };
DR}I+<*%aD LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
&|#[.ti1 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
Y'iyfnk BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
52tc|j6~# BOOL InitHotkey();
; /K6U BOOL UnInit();
j7kX"nz #endif
C:5-h(# ,mp<<%{u //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
7`;sX?R #include "stdafx.h"
Qa )+Tv #include "hook.h"
C`g
"Mk8 #include <windowsx.h>
n2B%}LLa #ifdef _DEBUG
:1j8!R5 #define new DEBUG_NEW
%N<5ST>( #undef THIS_FILE
208^Yu static char THIS_FILE[] = __FILE__;
c2M #endif
kP&I}RY #define MAX_KEY 100
&3Zb? #define CTRLBIT 0x04
pS ](Emn`. #define ALTBIT 0x02
VbvP!<8 #define SHIFTBIT 0x01
.c+U=bV- #pragma data_seg("shareddata")
NknS:r&2 HHOOK hHook =NULL;
)0exGx+: UINT nHookCount =0;
O?Bf (y static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
{k_\1t(/ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
?IHt T3'Rt static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
g&xj(SMj-$ static int KeyCount =0;
w8 :[w static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
*O~y6|U? #pragma data_seg()
)4=86>XJT HINSTANCE hins;
`z(o01y void VerifyWindow();
.))jR:{3 BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
=6Ok4Z //{{AFX_MSG_MAP(CHookApp)
IRm}?hHf // NOTE - the ClassWizard will add and remove mapping macros here.
Q/4-7 // DO NOT EDIT what you see in these blocks of generated code!
l[$GOLeS //}}AFX_MSG_MAP
uS`} END_MESSAGE_MAP()
<
bC'.m 2j%=o?me^p CHookApp::CHookApp()
-a)1L'R {
FprdP*/ // TODO: add construction code here,
zK5&,/ // Place all significant initialization in InitInstance
1DB{"8ov }
iN
Oj@3x O3o^%0 CHookApp theApp;
Ow/,pC >V LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
(`dz37@* {
),p0V
BOOL bProcessed=FALSE;
3O2G+G2 if(HC_ACTION==nCode)
~ps,U {
O]PM L` if((lParam&0xc0000000)==0xc0000000){// Key up
>SDQ@63E? switch(wParam)
toPbFU' {
5VTVx1P[8 case VK_MENU:
:1*E5pX0n MaskBits&=~ALTBIT;
'Eur[~k break;
>wh v*@Fr case VK_CONTROL:
Sxq@W8W MaskBits&=~CTRLBIT;
]%A> swCpn break;
xkDK5&V case VK_SHIFT:
"KP]3EyPc MaskBits&=~SHIFTBIT;
6NX#=A break;
lwf4ke default: //judge the key and send message
DSwb8q break;
~Q_7HJ=^$ }
^yPZ$Q for(int index=0;index<MAX_KEY;index++){
?2&= +QaT if(hCallWnd[index]==NULL)
OWewV@VXR continue;
3Qe|'E,U if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
;-VZV p}Y {
b~vV++ou_ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
1jd{AqHl bProcessed=TRUE;
\+V"JIStUj }
ar<8wq<4G }
csW\Q][ }
&qS%~h%2 else if((lParam&0xc000ffff)==1){ //Key down
I #1~CbR switch(wParam)
i=#`7pt%'a {
T>asH case VK_MENU:
LXo$\~M8G8 MaskBits|=ALTBIT;
G"?7 Z&+ break;
@\&j3A case VK_CONTROL:
CnB[ImMs(A MaskBits|=CTRLBIT;
N-upNuv break;
qhY+<S9 case VK_SHIFT:
l}/_(* MaskBits|=SHIFTBIT;
!=:>y WQ break;
M]PZwW8 default: //judge the key and send message
1k6asz^T break;
1]:,Xa+|S }
u&Ic for(int index=0;index<MAX_KEY;index++)
%8n<#0v-|4 {
t?>}0\1 if(hCallWnd[index]==NULL)
:o!Kz`J continue;
MOQ6&C`7q if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
B9NUafK= {
6#U~>r/ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
67rY+u% bProcessed=TRUE;
<CVX[R]U }
mvjx
&+q }
bpBn3f`?* }
(
3B1X if(!bProcessed){
eWDXV-xD for(int index=0;index<MAX_KEY;index++){
^}~Q(ji7 if(hCallWnd[index]==NULL)
7N 0Bj! continue;
x >a h, if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
q#3T
L< SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
8j>V?'Szk }
@FIL4sb }
:'bZ:J>f }
d=bKNA90 return CallNextHookEx( hHook, nCode, wParam, lParam );
:Ob4WU }
b~&cYk' "J,|),Yd BOOL InitHotkey()
9R$$(zB 1; {
UUfM7gq if(hHook!=NULL){
!LH;K nHookCount++;
7=N%$]DKZ return TRUE;
c{Z
"'t7 }
nX:E(9q7c else
E?+~S M1~ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
B`QF;,3S if(hHook!=NULL)
=iW hK~S nHookCount++;
sP^:*B0 return (hHook!=NULL);
dsw^$R} }
=*'yGB[x) BOOL UnInit()
g"n>v
c7 {
0Lj;t/mG if(nHookCount>1){
?:/J8s
[O nHookCount--;
?&0CEfa? return TRUE;
vfqXHc
unj }
8*8Y\" BOOL unhooked = UnhookWindowsHookEx(hHook);
2#$7!`6K if(unhooked==TRUE){
KLM6#6` nHookCount=0;
;sA
5&a>! hHook=NULL;
mH;t)dT }
7|=SZ+g return unhooked;
HAE$Np|>a }
l1zPL3"u_^ G$YF0Nc BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
4;~xRg;u&* {
@; 9KP6d BOOL bAdded=FALSE;
;PMPXN'z6 for(int index=0;index<MAX_KEY;index++){
@8J*vY =e if(hCallWnd[index]==0){
Q-h< av9 hCallWnd[index]=hWnd;
9u=]D> kb HotKey[index]=cKey;
R|Bi%q|4P HotKeyMask[index]=cMask;
/b{@'] bAdded=TRUE;
nZj&Ma7R KeyCount++;
Kc]
GE#~g break;
*RJD^hu }
9r\p4_V }
6@0?~ return bAdded;
) 5`^@zx }
q ) 5s'( uUaDesz~= BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
}6u}?>S {
D {E,XOi BOOL bRemoved=FALSE;
}:?_/$}; for(int index=0;index<MAX_KEY;index++){
.gNJY7`b if(hCallWnd[index]==hWnd){
%QDAog if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Yc[vH=gV} hCallWnd[index]=NULL;
ve/.q^JeJ HotKey[index]=0;
'yOx&~H] HotKeyMask[index]=0;
MYJDfI bRemoved=TRUE;
A\/DAVnI KeyCount--;
<!W9EM break;
@B+8' b$9 }
\HoVS }
aQWg?,Ju6 }
yYJ +vs return bRemoved;
+A
6kw%" }
L eUp! OpOR! void VerifyWindow()
z5^Se!`5 {
V-%jSe< for(int i=0;i<MAX_KEY;i++){
l0!`>Xx[b if(hCallWnd
!=NULL){ :d<F7`k
H
if(!IsWindow(hCallWnd)){ ayf;'1
hCallWnd=NULL; w&^Dbme
HotKey=0; #B$_ily)
HotKeyMask=0; d8jP@>
KeyCount--; #R=6$
} 0a$hK9BH
} Em<J{`k6
} L@ N\8mf
} 8
=3#S'n
QUdF`_U7
BOOL CHookApp::InitInstance() (a|Wq{`[
{ AdF[>Wv
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 7&dPrnQX=
hins=AfxGetInstanceHandle(); :; 3y^!
InitHotkey(); 6~Zq
return CWinApp::InitInstance(); Y,%G5X@S<
} wqn}t]
}PzYt~Z`@
int CHookApp::ExitInstance() N;av
{ BjUz"69
VerifyWindow(); }'TZ)=t{J
UnInit(); 75H5{#)
return CWinApp::ExitInstance(); ZnB|vfL?
} WB|SXto%4D
h,Tsb:Q"M
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file c:`&QDF
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) u/74E0$S
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ T CO^9RP<
#if _MSC_VER > 1000 OY#=s!]
M
#pragma once WXE{uGc
#endif // _MSC_VER > 1000 aSNTm8SYX
Y'i_EX|
class CCaptureDlg : public CDialog )e:u 6]
{ 3Q(#2tL=
// Construction 9Lxa?Y1
public: }3mIj<I1;
BOOL bTray; :~]ha
BOOL bRegistered; ur`:wR] 2?
BOOL RegisterHotkey(); 1=%\4\
UCHAR cKey; lo!_;`v=U
UCHAR cMask; fqU*y 6]
void DeleteIcon(); '=vD!6=0@
void AddIcon(); [L@ vC>G
UINT nCount; sHulaX{
void SaveBmp();
t@EHhiBz
CCaptureDlg(CWnd* pParent = NULL); // standard constructor 7w{>bYP
// Dialog Data x+7jJ=F
//{{AFX_DATA(CCaptureDlg) W.u}Q@
enum { IDD = IDD_CAPTURE_DIALOG }; ;M"JN:J8
CComboBox m_Key; GoNX\^A
BOOL m_bControl; _(s|@UT#
BOOL m_bAlt; &iD