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:
SlLw{Yb7\.
C#V ~Y 一、实现方法
,B}I?vN. t>)45<PEw 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:
7}O.wUKw% BKa-
k! #pragma data_seg("shareddata")
&)F*@C- HHOOK hHook =NULL; //钩子句柄
ikB Yd
}5 UINT nHookCount =0; //挂接的程序数目
G$zL)R8GE| static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Q?t^@ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
2I1uX&g static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
NG&_?|OmV static int KeyCount =0;
P>Euq'ajX static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
S"m cUU}} #pragma data_seg()
Pl=] Srw c?2MBtnu 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
J<gJc*Q h&3YGCl DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
qGmNz}4D5 X .F^$ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
''OfS D_g cKey,UCHAR cMask)
lS^(&<{ {
=,!\~`^ BOOL bAdded=FALSE;
"<+ih0Ma for(int index=0;index<MAX_KEY;index++){
T=a=B( if(hCallWnd[index]==0){
d@0Kr5_ hCallWnd[index]=hWnd;
H1"q HotKey[index]=cKey;
DciwQcG HotKeyMask[index]=cMask;
UM*jKi2]" bAdded=TRUE;
{%v-( KeyCount++;
q@5K6yE break;
Y<"7x#AB! }
cV{%^0?D }
vP@v.6gS, return bAdded;
%%ae^*[!n }
^I
mP`*X //删除热键
}U w&Ny BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
`~UZU@/x {
o'<^LYSnB BOOL bRemoved=FALSE;
bOp54WI-g for(int index=0;index<MAX_KEY;index++){
1{Mcs%W;w5 if(hCallWnd[index]==hWnd){
FSuAjBl0- if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
)QagS.L{z hCallWnd[index]=NULL;
mnk"Vr` L HotKey[index]=0;
{ x0 t HotKeyMask[index]=0;
6C4'BCYW( bRemoved=TRUE;
+|Hioq*,t KeyCount--;
; |/leu8 break;
"P@>M) -9Z }
XNMa0 }
gk BdR + }
CRve.e8J return bRemoved;
4n1; Bh$ }
%owsBO+ yV3^Qtb! ZD#9&q'4< DLL中的钩子函数如下:
\AUI|M;' =$8nUX` LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
am_gH {
tj]9~eJ- BOOL bProcessed=FALSE;
ZlYPoOq if(HC_ACTION==nCode)
*=ZsqOHwG {
U'UQ|%5f if((lParam&0xc0000000)==0xc0000000){// 有键松开
Ch()P.n? switch(wParam)
qjAWeS/ {
/N>e&e[35\ case VK_MENU:
1T_QX9 MaskBits&=~ALTBIT;
h0oMTiA break;
kc'pN&]r: case VK_CONTROL:
@pI5lh MaskBits&=~CTRLBIT;
f=!PllxL: break;
CxhY$%C (L case VK_SHIFT:
d8SE,A& MaskBits&=~SHIFTBIT;
m\>a,oZH break;
rKHY?{! default: //judge the key and send message
Fhz*&JC# break;
H+}"q$ }
@UBjq%z for(int index=0;index<MAX_KEY;index++){
~1m2#> if(hCallWnd[index]==NULL)
R8L_J6Kpa continue;
uJR%0 E7! if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
U`Jy!x2m {
.O*bILU SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
)4?x5# bProcessed=TRUE;
Ed0I WPx }
9jp:k><\(c }
?T_3n: }
v]%WH~> else if((lParam&0xc000ffff)==1){ //有键按下
*?+V65~dW switch(wParam)
Giq=*D+ {
5WqXo{S case VK_MENU:
O?8Ni=] MaskBits|=ALTBIT;
Nfe>3uQK break;
$I#q case VK_CONTROL:
8;y&Pb~) MaskBits|=CTRLBIT;
rV({4cIe9R break;
f\;65k_jq case VK_SHIFT:
G1t\Q-|l0 MaskBits|=SHIFTBIT;
p_ Fy>j break;
]Q
"p\@\! default: //judge the key and send message
/MB{Pmk$R break;
jEc|]E }
IvpcSam' for(int index=0;index<MAX_KEY;index++){
;Z j]~| if(hCallWnd[index]==NULL)
+9O5KI?P continue;
{
74mf'IW if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
7:]Pl=:X {
J`IDlGFYp SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
G
a;.a bProcessed=TRUE;
M L7\BT }
Ov-b:lH }
Gc.P,K/hr }
2nb:) if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
2RF^s.W for(int index=0;index<MAX_KEY;index++){
$rXh0g if(hCallWnd[index]==NULL)
r[.>P$U
continue;
obK*rdg, if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
9p 4"r^ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Obw?_@X //lParam的意义可看MSDN中WM_KEYDOWN部分
Z3;!l }
C 8#@+ Q. }
wOQ#N++C }
<?D[9Mk$ return CallNextHookEx( hHook, nCode, wParam, lParam );
IfO;S*Qt }
*F>v]8 vN4Qdpdb 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:
30PZ{c&Rll 1tCQpf BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
H7+Xs% BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
E^_wI> {Z; jhR, 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:
x#~ x;) d1!i(MaV! LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
9p$V)qdX {
#{r#;+ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
P+MA*: {
A392=:N+Q //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
`"i Y* SaveBmp();
o01kYBD return FALSE;
>$gG/WD?KR }
ej&<GM| …… //其它处理及默认处理
sDgXU@ }
WqxUX H O 2{)WWOT ERUt'1F?] 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。
kE.x+2 4fh^[\ 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。
0s#vwK13 E'1+ Yq 二、编程步骤
X u"R^
)f+U~4G& 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";
TUL_TR 0Q"u#V Sp 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
]U[X1W+@ T0Yiayt 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;
jk\ dG16 y#Ht{)C 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;
\&V0vN1 y AF+bCXo 5、 添加代码,编译运行程序。
~/_9P Fk =1h9rlFj"D 三、程序代码
3qH QX?a d{et8N ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
nmlPX7!{$ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
E{=2\Wkcp #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
O#nR>1h #if _MSC_VER > 1000
_ 7oV< #pragma once
R cY>k #endif // _MSC_VER > 1000
)T907I| #ifndef __AFXWIN_H__
3`hUo5K #error include 'stdafx.h' before including this file for PCH
yTE%hHH]&[ #endif
aYL|@R5;e #include "resource.h" // main symbols
Gy1xG.yM~ class CHookApp : public CWinApp
D0Z\Vvy {
`&M{cfp_ public:
2Zuq?1= CHookApp();
O<9~Kgd8h // Overrides
r%wA&FQ8U // ClassWizard generated virtual function overrides
^x*nq3^h\ //{{AFX_VIRTUAL(CHookApp)
6
y"-I!& public:
nU+tM~C%a virtual BOOL InitInstance();
?:^mBb)T virtual int ExitInstance();
n?#!VN3 //}}AFX_VIRTUAL
0)YbI! //{{AFX_MSG(CHookApp)
Nd:R"
p*8 // NOTE - the ClassWizard will add and remove member functions here.
J MX6yV // DO NOT EDIT what you see in these blocks of generated code !
"wH) mQnd //}}AFX_MSG
HDM<w+ZxX DECLARE_MESSAGE_MAP()
%v5R#14[n };
1rw0sAuGy LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
W]<$0 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
[\)oo BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
y<W8Q<9 BOOL InitHotkey();
#gQF' BOOL UnInit();
rh2LGuo4m #endif
<Y 4:'L6 >-T`0wI //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
*, Ld/O;s #include "stdafx.h"
iMF<5fLH& #include "hook.h"
'f8(#n=6qP #include <windowsx.h>
>YW\~T #ifdef _DEBUG
N5|Rmfo1 #define new DEBUG_NEW
I^*'.z!4Q #undef THIS_FILE
1`f_P$&Z_J static char THIS_FILE[] = __FILE__;
@
\.;b9 #endif
"SWMk! #define MAX_KEY 100
-9P2`XQ^ #define CTRLBIT 0x04
,Y_{L|:w #define ALTBIT 0x02
C>^D*C( #define SHIFTBIT 0x01
[{[N( g&d #pragma data_seg("shareddata")
k0?ZYeHC HHOOK hHook =NULL;
>QQ(m\a$ UINT nHookCount =0;
hRaf# static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
VCNT4m static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
Eu@5L9A static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
\`'KlF2 static int KeyCount =0;
<Pqv;WI|R static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
@54*.q$ #pragma data_seg()
h>S[^
-, HINSTANCE hins;
78#!Q.## void VerifyWindow();
$<@\-vYvr@ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
hSqY$P //{{AFX_MSG_MAP(CHookApp)
A )nW // NOTE - the ClassWizard will add and remove mapping macros here.
fT:}Lj\L1 // DO NOT EDIT what you see in these blocks of generated code!
PsjbR //}}AFX_MSG_MAP
$BN15x0/:~ END_MESSAGE_MAP()
yT OyDm- XR# ;{p+b CHookApp::CHookApp()
a+41|)pt {
/%x7+Rl\-^ // TODO: add construction code here,
!&kL9A). // Place all significant initialization in InitInstance
+,'T=Ic{ }
zbw7U'jk `cP <}^] CHookApp theApp;
\L!uHAE2a LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
S^RUw {
qG8s;_G BOOL bProcessed=FALSE;
r >{G`de4 if(HC_ACTION==nCode)
,1n
>U?5 {
v vu<:16 if((lParam&0xc0000000)==0xc0000000){// Key up
S[M4ukYK switch(wParam)
A(6xg)_XQ {
-H(vL= case VK_MENU:
BWPP5X9 MaskBits&=~ALTBIT;
Lf}8qB#Y break;
O0l^*nZ46t case VK_CONTROL:
rp!
LP#* MaskBits&=~CTRLBIT;
,#u\l>&$ break;
i`U:gw case VK_SHIFT:
_v5t<_^N MaskBits&=~SHIFTBIT;
sOFa!bdPW break;
\9c$`nn default: //judge the key and send message
ZwI
1* f break;
jrJR1npB }
5vp|?-\h> for(int index=0;index<MAX_KEY;index++){
:1fagaPg if(hCallWnd[index]==NULL)
+`en{$%% continue;
I %_MV if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
{gF0Xm% {
<dR,' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Dk)}|GJ()" bProcessed=TRUE;
.:1qK<vz }
'8`T|2 }
S0w> hr }
M8W# io else if((lParam&0xc000ffff)==1){ //Key down
j\)H switch(wParam)
DQ!J!ltQ {
iSp case VK_MENU:
e=f .y< MaskBits|=ALTBIT;
60B-ay0e$b break;
nnCug case VK_CONTROL:
Bt~s*{3$8 MaskBits|=CTRLBIT;
E{^^^"z P break;
:xeLt; case VK_SHIFT:
IhonnLLW MaskBits|=SHIFTBIT;
L ^Y3=1#"g break;
Z[#IfbYt default: //judge the key and send message
;_JH:}j break;
[$\>~nj= }
:iCM=k for(int index=0;index<MAX_KEY;index++)
T-L5zu {
lglYJ, if(hCallWnd[index]==NULL)
!e8i/!}^S continue;
I lG:X)V% if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
cy3ww}) {
@ RR\lZ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
_vYzF+ bProcessed=TRUE;
<)#kq1b? }
%]4-{%v }
4,1oU|fz }
NrJzVGeS if(!bProcessed){
QXQ for(int index=0;index<MAX_KEY;index++){
Bku'H if(hCallWnd[index]==NULL)
,+L
KJl continue;
pG yRX_; if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
+$pJ5+v SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
7 ^I:=qc72 }
>9(i)e }
UmP'L! }
2R@%Y/ return CallNextHookEx( hHook, nCode, wParam, lParam );
Ti= 3y497S }
Aka^e\Y@6* womq^h6 BOOL InitHotkey()
2w1tK {
M []OHw if(hHook!=NULL){
zXre~b03ZS nHookCount++;
`BT*,6a return TRUE;
{yq8<? }
TbNGgjT else
:c4kBl%gJ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
kV)'a if(hHook!=NULL)
#)74X%4( nHookCount++;
!IAKVQ return (hHook!=NULL);
DX@}!6|T }
ki4f*Ej BOOL UnInit()
B=zMYi {
*8\(FVyG^ if(nHookCount>1){
@-6?i) nHookCount--;
hZuYdV{'h return TRUE;
v]bAWo }
f=ib9WbR# BOOL unhooked = UnhookWindowsHookEx(hHook);
-9G]x{> if(unhooked==TRUE){
KOSyh<& nHookCount=0;
0|C[-ppr hHook=NULL;
?0J0Ij, }
JSjYC0e return unhooked;
q|{tQJfYg }
S}gD,7@ XZO<dhZX: BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
OV|Z=EwJ {
@hT;Bo2G] BOOL bAdded=FALSE;
_i@x@:_l for(int index=0;index<MAX_KEY;index++){
N$Hqa^!'T if(hCallWnd[index]==0){
M {x ie hCallWnd[index]=hWnd;
i QqbzOY HotKey[index]=cKey;
WEC-<fN|Y\ HotKeyMask[index]=cMask;
|h,FUj<r bAdded=TRUE;
jOl 1_ KeyCount++;
NgxO&Zp break;
RndOm.TE }
kPJ~X0Fr{t }
?UK:sF|(O return bAdded;
Yq;&F0paK }
MVAc8d S ,k%8yK BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
M(S{1|,V {
y h-9u BOOL bRemoved=FALSE;
>4'21,q for(int index=0;index<MAX_KEY;index++){
r5)f82pQ if(hCallWnd[index]==hWnd){
A_Gp&acs$ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
@Z2/9K%1' hCallWnd[index]=NULL;
XI
g|G}i. HotKey[index]=0;
rqC1 HotKeyMask[index]=0;
lt%-m@#/ bRemoved=TRUE;
wea\8[U3" KeyCount--;
+~:0Dxv W break;
N7B}O*; }
AzX(~Qc }
`q1}6U/k }
?M<|r11} return bRemoved;
uN&M\( }
riEqW}{ )`RZkCe void VerifyWindow()
fiqj;GW {
^z?=?%{ for(int i=0;i<MAX_KEY;i++){
R7t
bxC if(hCallWnd
!=NULL){ gD40y\9r
if(!IsWindow(hCallWnd)){ PDZ)*$EE
hCallWnd=NULL; <Am^z~[
HotKey=0; -AeHY'T
HotKeyMask=0; tQnJS2V"{u
KeyCount--; F\P!NSFZV
} ke</x+\F
} |vN$"mp^a
} "j;!_v>=f`
} 73#9NZR
{lKEZirO
BOOL CHookApp::InitInstance() -9i+@%{/
{ :\T_'Shq
AFX_MANAGE_STATE(AfxGetStaticModuleState()); /K&