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:
tq51;L
YPA$38 一、实现方法
$VF$Ok> 1-E utq 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:
v:n[H]K| +,TrJg #pragma data_seg("shareddata")
RE1M4UV. HHOOK hHook =NULL; //钩子句柄
)JJF}m= UINT nHookCount =0; //挂接的程序数目
vin3
i&k static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
#)3 B static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
"2p\/VfA static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
~YByyJG
static int KeyCount =0;
p|@#IoA/e static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
N|3#pHm@ #pragma data_seg()
kI2+& Ejnk\ 8: 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。
'8(UiB5d C>SOd] 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:
^'fgQyj y>)c?9X BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
jmcys
_N3 cKey,UCHAR cMask)
_]{LjJ!M {
z;_vl BOOL bAdded=FALSE;
|dDKO for(int index=0;index<MAX_KEY;index++){
Ey=}bBx if(hCallWnd[index]==0){
>?6HUUQ hCallWnd[index]=hWnd;
JpxQS~VX HotKey[index]=cKey;
Nr).*]g@~ HotKeyMask[index]=cMask;
dGz4`1(> bAdded=TRUE;
Z]x6np KeyCount++;
!~V^GlY break;
\
FJ ae }
c _!!DEe7 }
6Nt/>[ return bAdded;
7p1B"% }
A(n#k&W1fZ //删除热键
ap2g^lQXq BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
s+z 5"3'n {
CxSh.$l BOOL bRemoved=FALSE;
4C;y2`C for(int index=0;index<MAX_KEY;index++){
Kr;=4xg= if(hCallWnd[index]==hWnd){
G*jq5_6 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
N;k )> hCallWnd[index]=NULL;
xLfv:Rp HotKey[index]=0;
b*/Mco 9O HotKeyMask[index]=0;
#=;vg bRemoved=TRUE;
B2|0.G|[j KeyCount--;
Zo
}^"u break;
IAmZ_2 }
!
h92dH }
eTay/i<- }
o\; hF3 return bRemoved;
\Hf/8!q }
wNn=JzP pf%;* R[)bGl6# DLL中的钩子函数如下:
@#$(Cs*{] 9!kp3x/` LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
4nGt*0Er {
c{KJNH%7 BOOL bProcessed=FALSE;
[J(b"c6 if(HC_ACTION==nCode)
YD0hDp {
R/kJUl6HEl if((lParam&0xc0000000)==0xc0000000){// 有键松开
/lh1sHgD switch(wParam)
&`m$Zzl;
{
nh"dPE7^ case VK_MENU:
E31YkD.A MaskBits&=~ALTBIT;
7#NHPn break;
9v?@2sOoE case VK_CONTROL:
!2^~ar{2 MaskBits&=~CTRLBIT;
1[$zdv{A break;
W0Y
,3;0 case VK_SHIFT:
=p"ma83 MaskBits&=~SHIFTBIT;
p\9}}t7n break;
ST0TWE' default: //judge the key and send message
@65xn)CD{ break;
GN:|b2 " }
t`R{N1 for(int index=0;index<MAX_KEY;index++){
^!0z+M:>^ if(hCallWnd[index]==NULL)
*'-t_F'; continue;
[HUK
9hG if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
%u_dxpx {
O&yAFiCd SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
|0?v4%g bProcessed=TRUE;
]61HQ }
T,rRE7 }
ts}OE }
GZKYRPg else if((lParam&0xc000ffff)==1){ //有键按下
Yyr9Kj: switch(wParam)
xUCq%r_ {
DdUw~n, case VK_MENU:
:Fu7T1 MaskBits|=ALTBIT;
c b&Yf1 break;
/&_q"y9 case VK_CONTROL:
}P-C-L{yE( MaskBits|=CTRLBIT;
{@3v$W~7M break;
E^br-{|{ case VK_SHIFT:
,<)D3K< MaskBits|=SHIFTBIT;
L F } d break;
TA2ETvz^ default: //judge the key and send message
! K_<hNG& break;
E_DQ.!U!o }
odC"#Rb for(int index=0;index<MAX_KEY;index++){
Xo]2iQy if(hCallWnd[index]==NULL)
yU4mS;GX continue;
} .Z` if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
/BD'{tZ]Sl {
gIusp917 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
0@{0#W3R bProcessed=TRUE;
@rDBK] V }
k0#s{<I]E }
h]+;"v6 / }
\E<Qi3W>* if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
i/H;4#Bz for(int index=0;index<MAX_KEY;index++){
H(P]Z~et if(hCallWnd[index]==NULL)
Yf~Kzv1]* continue;
hITYBPqRO if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
1 ]
cLbJ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
0I<L<^s3^U //lParam的意义可看MSDN中WM_KEYDOWN部分
R=<::2_Y96 }
FfrC/"N }
#D|%r-:" }
DR:DXJc return CallNextHookEx( hHook, nCode, wParam, lParam );
ViMl{3 }
aq8./^ UnP<`z# 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:
(GC5r#AnS ]'M B3@T BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
UcOP 0_/ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
+,AzxP
_y 8ih_S2Cd 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:
D7JrGaF{ $u'"C|>8 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
) \T H' {
oz)4YBf if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
sgGA0af {
a0gg<Ml //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
;<B SaveBmp();
Wf"GA i return FALSE;
OKK Ko`RN }
D4|Ajeo;1 …… //其它处理及默认处理
b1jDbiH& }
9_iwikD wWfj#IB;R =~Qg(=U0U 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
z rG JGTsVa2 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
SA&(%f1d naH(lz|v 二、编程步骤
%.r\P@7/Q DB-79U %W 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
.5o~^ /|P{t{^WM 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
f!R7v|jP %;v~MC@ 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
l9="ccM "aCB} 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
#k|f>D4 =E%@8ZbK 5、 添加代码,编译运行程序。
adIrrK 6SH0
y 三、程序代码
*jWh4F, f$kbb6juL ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
n8=Dzv0 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
8IQ}%|lN #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
+hr|$ #if _MSC_VER > 1000
4K~=l%l #pragma once
<I
tS_/z #endif // _MSC_VER > 1000
)UF'y{K} #ifndef __AFXWIN_H__
ZvT,HJ0? #error include 'stdafx.h' before including this file for PCH
![\P/1p #endif
OG?7(
UJ #include "resource.h" // main symbols
+h+ 7Q'k class CHookApp : public CWinApp
tP*Kt'4W {
M!Ao!D[ public:
0#eb] c CHookApp();
[J}eNprg // Overrides
?HZ^V // ClassWizard generated virtual function overrides
Ys}^hy //{{AFX_VIRTUAL(CHookApp)
Q2r[^Z public:
;*j
K! virtual BOOL InitInstance();
Z'y &11 virtual int ExitInstance();
{}k3nJfE //}}AFX_VIRTUAL
k?&GL!? //{{AFX_MSG(CHookApp)
EFh^C.S8 // NOTE - the ClassWizard will add and remove member functions here.
Xm>zT'B_tJ // DO NOT EDIT what you see in these blocks of generated code !
YW&K,)L@ //}}AFX_MSG
OObAn^bt DECLARE_MESSAGE_MAP()
~5%3] };
JZ`h+fAt LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
g=Xy{Vm
BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
UCfouQ Cj BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
)1M2}11uS BOOL InitHotkey();
,3T"fT-( BOOL UnInit();
4s9@4 #endif
so$(-4(E O *->*p35 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
mHW%:a\L #include "stdafx.h"
Gt*K:KT=L #include "hook.h"
0Atha>w^o~ #include <windowsx.h>
h+j^VsP zB #ifdef _DEBUG
z{\tn.67 #define new DEBUG_NEW
`14@dk
#undef THIS_FILE
|e2s\?nB0S static char THIS_FILE[] = __FILE__;
m!w|~Rk #endif
' *a}*(0OA #define MAX_KEY 100
r|4D.O] #define CTRLBIT 0x04
'q$ Ym0nL #define ALTBIT 0x02
.#SgU<Wq #define SHIFTBIT 0x01
MJ?t{= #pragma data_seg("shareddata")
vbeE}7 *2 HHOOK hHook =NULL;
jIe
/X] UINT nHookCount =0;
1_q!E~) static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
n:/!{. static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
N WF h<
static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
=KOi#;1 static int KeyCount =0;
v/rBjUc+X static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
lqmQQ*Z #pragma data_seg()
2{~`q HINSTANCE hins;
%|}*xMQ void VerifyWindow();
/96lvn]8lO BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
)M+po-6$1 //{{AFX_MSG_MAP(CHookApp)
{!wW,3|Pu // NOTE - the ClassWizard will add and remove mapping macros here.
HYGd
:SeH // DO NOT EDIT what you see in these blocks of generated code!
p:y\{k" //}}AFX_MSG_MAP
IS(F_< . END_MESSAGE_MAP()
s) U1U6O P8By~f32_ CHookApp::CHookApp()
;xz_H$g {
1-?i*C // TODO: add construction code here,
5wx~QV=Hh // Place all significant initialization in InitInstance
7{O
iV}]" }
JZ-@za6u ^-q{:lx CHookApp theApp;
<Qih&P9;> LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
*izCXfW7 {
Xzg >/w
8J BOOL bProcessed=FALSE;
)2Sh oFF if(HC_ACTION==nCode)
iTAj${ > {
?.<
Qgd if((lParam&0xc0000000)==0xc0000000){// Key up
bHRn}K+<}c switch(wParam)
xJ{r9~ {
W;7$Dq: case VK_MENU:
iu8Q &Us0P MaskBits&=~ALTBIT;
96~y\X@x break;
lPxhqF5pP case VK_CONTROL:
T})q/oUqK MaskBits&=~CTRLBIT;
J~WT;s break;
iQ:eR]7X case VK_SHIFT:
%?].(
Lc MaskBits&=~SHIFTBIT;
%M1l[\N break;
P7=`P default: //judge the key and send message
ef '?O break;
=l/Dc=[ }
&gr 8;O:0 for(int index=0;index<MAX_KEY;index++){
}YdC[b$j^ if(hCallWnd[index]==NULL)
mm+V*L{x continue;
5)XUT`;'){ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
,P}7e)3 {
hGV_K" ~I0 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
^uUA41o`eJ bProcessed=TRUE;
}W:Z>vam+ }
8,IF%Z+LI }
5|~g2Zz{; }
qqZ4K:oC, else if((lParam&0xc000ffff)==1){ //Key down
tT)s,R% switch(wParam)
>Z_;ZMu) {
tkk8b6%h?p case VK_MENU:
o"X..m< MaskBits|=ALTBIT;
pp(09y`] break;
q&>fKS nKs case VK_CONTROL:
1O0. CC,p MaskBits|=CTRLBIT;
G) KI{D break;
hmkb!) case VK_SHIFT:
XV%R Mr6 MaskBits|=SHIFTBIT;
59 g//;35@ break;
H ;=^
W default: //judge the key and send message
#6|ve?`I break;
";7N$hWE }
P=,\wM6T| for(int index=0;index<MAX_KEY;index++)
%!A:Ka!m. {
:$u[1&6 if(hCallWnd[index]==NULL)
6~0kb_td continue;
cKkH*0B5 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
~L<"]V+B {
d'MZ%.# SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
QObVJg,GD bProcessed=TRUE;
02[m{a- }
Q?1.GuF }
a_}C*+D }
\K\eq>@6 if(!bProcessed){
r-$xLe7a for(int index=0;index<MAX_KEY;index++){
q>'#; QA if(hCallWnd[index]==NULL)
D6@ c|O{Q continue;
!5De?OXe if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
\8C<nh SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
#n+u>x.O }
iYT?6Y|+ }
HN367j2 e }
Ln&~t(7 return CallNextHookEx( hHook, nCode, wParam, lParam );
Z+U -+eG }
s) s9Z,HY uVD^X* BOOL InitHotkey()
qB_s<cpn> {
~
i+XVo if(hHook!=NULL){
[>dDRsZ nHookCount++;
`` g return TRUE;
X);'[/]E* }
>>J$`0kM* else
,}W|cm> hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
rWJ5C\R
if(hHook!=NULL)
o?/H<k\5 nHookCount++;
{jYVA~.|Z return (hHook!=NULL);
B<BS^waU }
0/DO"pnL@ BOOL UnInit()
Ng;?hT w {
6X A(<1P if(nHookCount>1){
g#74c'+ nHookCount--;
REU&8J@k&? return TRUE;
fWA#n }
>F7HKwg}Z BOOL unhooked = UnhookWindowsHookEx(hHook);
H%l-@::+$ if(unhooked==TRUE){
C;:=r:bth nHookCount=0;
(=u!E+N hHook=NULL;
bnkZWw'9 }
QlB9m2XB return unhooked;
)=gU~UV }
*ilVkV"U ?0dmw?i BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
}[|9vF"g.y {
[g}#R#Y) BOOL bAdded=FALSE;
vde!k_,wZ for(int index=0;index<MAX_KEY;index++){
`-U?{U}H if(hCallWnd[index]==0){
6B@e[VtG$ hCallWnd[index]=hWnd;
YBj*c$.D0 HotKey[index]=cKey;
yI|x
5f HotKeyMask[index]=cMask;
F;`c0ja] bAdded=TRUE;
HFjSM~ KeyCount++;
8*b{8%<K break;
T&/n.-@nk }
cz/E }
Q{S{|.w- return bAdded;
$LuU }
dr"$@ jcJ@A0] BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
pe,y'w{ {
q90RTX'CY BOOL bRemoved=FALSE;
<L8FI78[* for(int index=0;index<MAX_KEY;index++){
i75\<X if(hCallWnd[index]==hWnd){
e%ro7~ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
8dx7@y?z hCallWnd[index]=NULL;
b/oNQQM#Dk HotKey[index]=0;
^zT=qBl HotKeyMask[index]=0;
|95K bRemoved=TRUE;
Tw$tE: KeyCount--;
R73@!5N% break;
RgH 6l2 }
v9@_DlV\ }
Lbrn8,G\ }
(FGy"o%TP' return bRemoved;
onmkg}&_ }
E71H=C 4 @^ta)Ev void VerifyWindow()
$A 5O> {
_VgFuU$h for(int i=0;i<MAX_KEY;i++){
o@PvA1 if(hCallWnd
!=NULL){ !!ZGNZ_
if(!IsWindow(hCallWnd)){ oVP,ar0G
hCallWnd=NULL; T[e+iv<8j
HotKey=0; sF :pwI5^
HotKeyMask=0; k
t!@}QP
KeyCount--; I_Lm[
} :/SGB3gb1t
} xv147"w'v
} I8@leT\9M
} '-f` 5 X
_&gO>G,uy
BOOL CHookApp::InitInstance() wpN [0^M-0
{ zobFUFx
AFX_MANAGE_STATE(AfxGetStaticModuleState()); P}Mu|AEG
hins=AfxGetInstanceHandle(); cr0/.Zv)
InitHotkey(); Vr&
GsT
return CWinApp::InitInstance(); >mvE[iXRG?
} gGCr~.5
P5G0fq7
int CHookApp::ExitInstance() DsxNg
{ |*ZM{$
VerifyWindow(); v0&D