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:
)a^&7
xhALJfv 一、实现方法
5YrzOqg= \(??Ytc<B 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:
*L<EGFP f#c}}>V8 #pragma data_seg("shareddata")
6GuTd HHOOK hHook =NULL; //钩子句柄
@.L#u#
UINT nHookCount =0; //挂接的程序数目
^C
K!=oO static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
U R^r> static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
DlzL(p@r static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
X}GX6qAdt static int KeyCount =0;
pauO_'j_1p static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
zeGWM,! #pragma data_seg()
|K.I%B U/Cc!WXV] 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。
Ifp8oL? S; H0b{`!'Fs: 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:
;-JF1p 7; b0}dy\dnQ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
m2m
;|rr cKey,UCHAR cMask)
,tXI*R {
-medD G BOOL bAdded=FALSE;
`{ Ox=+]M for(int index=0;index<MAX_KEY;index++){
c{kpgN if(hCallWnd[index]==0){
LTf)`SN %' hCallWnd[index]=hWnd;
C#[P<= v HotKey[index]=cKey;
vAP1PQX; HotKeyMask[index]=cMask;
b|V<Kp bAdded=TRUE;
&am<_Tn*3 KeyCount++;
Q0-gU+ig break;
U^}7DJ }
z}SJ~WY'[ }
k/F#-},Q. return bAdded;
R.1.LB }
sC"w{_D@*4 //删除热键
6# bTlmcg BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
x'-gvbj! {
;~1xhpTk BOOL bRemoved=FALSE;
LmY[{.'tX for(int index=0;index<MAX_KEY;index++){
"Pc}-& if(hCallWnd[index]==hWnd){
JV,h1/a(" if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
|a)zuC hCallWnd[index]=NULL;
# a4OtRiI HotKey[index]=0;
6lpJ+A57# HotKeyMask[index]=0;
$J4)z&%dr bRemoved=TRUE;
~|<'@B!6 KeyCount--;
a?ete9Q+ break;
T:
My3&6 }
C6g p}% }
(-J'x%2) }
i\uj>;B return bRemoved;
IT#Li }
|"}7)[BW} 8@doKOA~T ~zZOogM< DLL中的钩子函数如下:
M]%dFQ { Mf-?_% LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Fsl="RB7f {
O=LW[h! BOOL bProcessed=FALSE;
Mp
js if(HC_ACTION==nCode)
#t2N=3dOj {
4YY!oDN: if((lParam&0xc0000000)==0xc0000000){// 有键松开
CY':'aWfa< switch(wParam)
s3sD7 @ {
b*tb$F case VK_MENU:
Js:U1q MaskBits&=~ALTBIT;
Ugo! break;
k{{
Y2B?C case VK_CONTROL:
AcJrJS)~ MaskBits&=~CTRLBIT;
HS*Y%* break;
r=37Q14v case VK_SHIFT:
s-I M MaskBits&=~SHIFTBIT;
%*K zP{ break;
/:!l&1l:p default: //judge the key and send message
K8&) kfyI break;
qHheF%[\5 }
'cu14m_ for(int index=0;index<MAX_KEY;index++){
d=D#cs;\ if(hCallWnd[index]==NULL)
+tt!xfy continue;
: &nF> if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
'5Kj"aD% {
+2tFX SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
\-Xtbm bProcessed=TRUE;
3_9CREZCl }
Z{t `f[ }
PZ#up{[o }
"\vQVZd-E else if((lParam&0xc000ffff)==1){ //有键按下
;,uATd| switch(wParam)
W!"QtEJ, {
!5h8sD; case VK_MENU:
NB44GP1-@ MaskBits|=ALTBIT;
+BO kHXk1 break;
Xk'Pc0@a case VK_CONTROL:
pyX:$j2R+% MaskBits|=CTRLBIT;
B[h^] k break;
unqUs08 case VK_SHIFT:
\N-3JO Vy MaskBits|=SHIFTBIT;
F+NX
[ break;
.nNZdta&= default: //judge the key and send message
$y.0h( break;
mJ(ElDG }
7;Lv_Y"b for(int index=0;index<MAX_KEY;index++){
Xf"<
>M if(hCallWnd[index]==NULL)
O8>&J-+2 continue;
"1XTgCu\ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
2yFT` 5+H4 {
AEx VKy SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
uzmYkBv bProcessed=TRUE;
t_16icF9U }
PJ&L7 }
$0OOH4 }
&PApO{#Q if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
ai?N!RX%H for(int index=0;index<MAX_KEY;index++){
1M_Vhs^ if(hCallWnd[index]==NULL)
WrRY3X continue;
.v}|Tp&k if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
{jwLVKT$ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
IG\Cj7{K^ //lParam的意义可看MSDN中WM_KEYDOWN部分
aO(iKlZ$ }
z6;hFcO }
oC}
u }
q7_Ttjn-DV return CallNextHookEx( hHook, nCode, wParam, lParam );
/s+IstW }
O&y`:# L^Q;M,.c; 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:
`:EhYj. f8WI@]1F BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
sSwY!"; BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
X<$DNRN mN.[bz 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
~:0w% oP4+:r)LKD LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
<s\ZqL$f {
h 6IXD N if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
fE)o-q6Z {
E`@Z9k1 ` //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
3OKs?i3A SaveBmp();
T>b"Gj/ return FALSE;
f}*:wj }
]auqf …… //其它处理及默认处理
!\BM }
D:IG;Rsc M=&,+#z<V /J!:_Nq 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。
@x743}Y\ nN-S5?X# 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。
xs Pt <HN{.p{ 二、编程步骤
olL? 6)gC 1ZRkVHiz0 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";
q
&{<HcP X's<+hK& 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
#pK"
^O*! S-Bx`e9 ' 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;
i'>5vU0?3 )cP)HbOd= 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;
4 83rU 'DpJ#w\81 5、 添加代码,编译运行程序。
dkDPze9l wsH _pF 三、程序代码
q~W:W}z bX:h"6{=R ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
q3h&V #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
dT?3Q;>B? #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
z5~W
>r #if _MSC_VER > 1000
f.66N9BHL, #pragma once
:-Py0{s #endif // _MSC_VER > 1000
dVHbIx #ifndef __AFXWIN_H__
cL03V? }
~ #error include 'stdafx.h' before including this file for PCH
rMZuiRz* #endif
B@6L<oZ #include "resource.h" // main symbols
g*LD}`X/- class CHookApp : public CWinApp
8 Zp^/43 {
wD{c$TJ?{F public:
pz)>y&_o CHookApp();
&(32s! qH // Overrides
NW 2`)e' // ClassWizard generated virtual function overrides
^eO/?D8~h //{{AFX_VIRTUAL(CHookApp)
b.\xPb public:
).(y#zJ7P virtual BOOL InitInstance();
*W^ZXhrZ virtual int ExitInstance();
r;[ =y<Yf //}}AFX_VIRTUAL
+DR$ >a //{{AFX_MSG(CHookApp)
=Tl_~OR // NOTE - the ClassWizard will add and remove member functions here.
t8xXGWk0 // DO NOT EDIT what you see in these blocks of generated code !
.PR+_a-X //}}AFX_MSG
{]dtA&8( DECLARE_MESSAGE_MAP()
7 [u>#8 };
~gMt
U LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
rJCb8x+5a BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
gM=:80 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
m9i/rK_ BOOL InitHotkey();
qnj'*]ysBC BOOL UnInit();
|rZMcl/ #endif
=EA:fq oo7}Hg> //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
xY!ud) #include "stdafx.h"
Nf3UVK8LtS #include "hook.h"
G\;6n #include <windowsx.h>
xb9+- {<J #ifdef _DEBUG
S 593wfc #define new DEBUG_NEW
g; ]' #undef THIS_FILE
PRTjXq6)5 static char THIS_FILE[] = __FILE__;
324XoMO #endif
&g^*ep~|# #define MAX_KEY 100
<.gDg?'3 #define CTRLBIT 0x04
GfEWms8z #define ALTBIT 0x02
m}=E$zPbO #define SHIFTBIT 0x01
"UNFB3 #pragma data_seg("shareddata")
Px
\cT HHOOK hHook =NULL;
.1{{E8Fj UINT nHookCount =0;
bDtb6hL static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
,%l}TSs static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
X~JP
1 static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
foQo`}"5 static int KeyCount =0;
(uDd_@a9t static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
vI5lp5( -3 #pragma data_seg()
p`c_5!H HINSTANCE hins;
)hj:Xpj9# void VerifyWindow();
E
BBd BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
0.n[_?<( //{{AFX_MSG_MAP(CHookApp)
flFdoEV.U) // NOTE - the ClassWizard will add and remove mapping macros here.
d,JDfG) // DO NOT EDIT what you see in these blocks of generated code!
@&WHX# //}}AFX_MSG_MAP
Jut&J]{h END_MESSAGE_MAP()
u YT$$'S
G7al@ CHookApp::CHookApp()
JDE_*xaUV {
VLkAsM5}% // TODO: add construction code here,
$Emu*' // Place all significant initialization in InitInstance
N~mr@rXC }
FC,=g`Q! RLnL9)`W CHookApp theApp;
!+^'Ej)z LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Y`bTf@EP> {
sAL
]N][Y BOOL bProcessed=FALSE;
31G0B_T if(HC_ACTION==nCode)
Y6sX|~Zy {
8iJB'#''* if((lParam&0xc0000000)==0xc0000000){// Key up
RK|*yt"f" switch(wParam)
Wx{E\ l {
~:bdS 4w case VK_MENU:
'Uf?-t*LT@ MaskBits&=~ALTBIT;
6xJffl break;
\?^2}K/ case VK_CONTROL:
Z}dK6h5+' MaskBits&=~CTRLBIT;
e:9EP, break;
V1V0T , case VK_SHIFT:
!!^z6jpvn MaskBits&=~SHIFTBIT;
<dH@e break;
Q,xL8i
M, default: //judge the key and send message
l_+@Xpl break;
>dt*^}* }
Ms(xQ[#+ for(int index=0;index<MAX_KEY;index++){
gK[;"R)4o@ if(hCallWnd[index]==NULL)
tZ9i/ =S continue;
!V37ePFje if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
1Qf}nWy {
$?0ch15/ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
gtA34iw bProcessed=TRUE;
UDg's }
UlE%\L0GD& }
EaO@I.[ }
DdgiY9a. else if((lParam&0xc000ffff)==1){ //Key down
6&eXQl switch(wParam)
:V)jm`)#+ {
]zSFX
=~(S case VK_MENU:
^}d]O( MaskBits|=ALTBIT;
P6 OnE18n break;
JF 4A case VK_CONTROL:
-Qn7+?P MaskBits|=CTRLBIT;
]19VEH break;
2L^)k?9>g+ case VK_SHIFT:
@ivd|*?k0 MaskBits|=SHIFTBIT;
L9D`hefz break;
d7X&3L%Oq default: //judge the key and send message
K}R+~<bIY break;
p%"dYH%]&0 }
x.?5-3|d$ for(int index=0;index<MAX_KEY;index++)
,JV0ib, {
RU:Rt' if(hCallWnd[index]==NULL)
e /JQ #A continue;
'+cI W(F? if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
y~
=H`PAE {
`um,S SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
^hC'\09=c bProcessed=TRUE;
2ndn8_l }
\j>7x }
`@h|+`h }
+tqErh?Al if(!bProcessed){
85GIEUvH/ for(int index=0;index<MAX_KEY;index++){
&[.`xZ(| if(hCallWnd[index]==NULL)
H,!xTy"Wh continue;
)#}>,,S if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
RwWg:4 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
"#j}F u_! }
B )r-,M }
A IP~A]T }
az(<<2= return CallNextHookEx( hHook, nCode, wParam, lParam );
PLyity-L[7 }
\n)',4mY Zh<;r;2 BOOL InitHotkey()
)|F|\6:ne {
iEr,ly if(hHook!=NULL){
[]>'Dw_r nHookCount++;
kz"uTJK return TRUE;
9Yx(u2PQ }
'x!\pE- else
afEa@et' hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
fGo4&( U if(hHook!=NULL)
IY`p7 )#i nHookCount++;
=?fz-HB return (hHook!=NULL);
&v{Ehkr* }
,BU;i%G&s BOOL UnInit()
7~/ cz_ {
%z><)7 if(nHookCount>1){
I &t~o nHookCount--;
Eah6"j!B8n return TRUE;
OU[<\d }
|p11Jt[ BOOL unhooked = UnhookWindowsHookEx(hHook);
-Aj)<KNx[ if(unhooked==TRUE){
$cCC
1=dW nHookCount=0;
V#t_gS hHook=NULL;
X
W)TI }
"ZuuSi return unhooked;
&XP(D5lf`B }
ff"wg\O4 %@/^UE: BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
J-F".6i5 {
jVj5 ; } BOOL bAdded=FALSE;
XIeLu"TSL for(int index=0;index<MAX_KEY;index++){
~Iu! B
Y if(hCallWnd[index]==0){
^:eZpQ [, hCallWnd[index]=hWnd;
\hB BG8=& HotKey[index]=cKey;
)O]T}eI HotKeyMask[index]=cMask;
@;Ttdwg#J bAdded=TRUE;
6o3
bq| KeyCount++;
mPV<a&U break;
kSQ8kU_w+ }
'|C3t!H` }
ly[LF1t return bAdded;
E$e7(D }
~4S$+*'8 3FEJ
9ZyG BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
b'H'QY
{
RpHlq BOOL bRemoved=FALSE;
}'X=&3m for(int index=0;index<MAX_KEY;index++){
hvd}l8 if(hCallWnd[index]==hWnd){
Y::0v@&( if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
H"C'<(4*\ hCallWnd[index]=NULL;
]n22+]D HotKey[index]=0;
_"DS?`z6 HotKeyMask[index]=0;
4`IM[DIG~ bRemoved=TRUE;
y7R#PkQ~ KeyCount--;
mo0\t#jA break;
o\AnM5 }
L[` l80 }
Wgq|Q* }
OG,P"sv return bRemoved;
sGvbL-S-f: }
GXNf@& [|u^:&az void VerifyWindow()
8sG3<$Z^ {
$Gn.G_"v for(int i=0;i<MAX_KEY;i++){
e%4?-{( if(hCallWnd
!=NULL){ 29R-Up!SVN
if(!IsWindow(hCallWnd)){ WL$^B@gXQ
hCallWnd=NULL; INZVe(z
HotKey=0; yqK4 "F&
HotKeyMask=0; qfkHGW?1/j
KeyCount--; |.IH4
K
} )&DAbB!O
} =BsV`p7rU
} mYBEjZB
} [&Xp]:M'D
;|N:FG
BOOL CHookApp::InitInstance() (}"D x3K
{ 'm%{Rz>j
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 2EY"[xK|
hins=AfxGetInstanceHandle(); ?HZp@&
InitHotkey(); .=_p6_G
return CWinApp::InitInstance(); eE;tiX/
} -wlj;U
0ju1>.p
int CHookApp::ExitInstance() SGd]o"VF
{ ZSMed(//b
VerifyWindow(); ]-PzN'5\'
UnInit(); I0=_=aZO(
return CWinApp::ExitInstance();
gwZ<$6
} &4'<