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:
=T0;F0@#4
6~@S,i1 一、实现方法
f,_EPh> WK<:(vu. 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:
wVms"U. SL O~ #pragma data_seg("shareddata")
~dFdO7 HHOOK hHook =NULL; //钩子句柄
CC<(V{Png UINT nHookCount =0; //挂接的程序数目
6|-V{ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
WE|-zo static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
'q_^28rK static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
S);SfNh%CL static int KeyCount =0;
x #Um` static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
RrG5`2 #pragma data_seg()
P wY~L3, $yA>j (k4 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
hN3*]s;/6z K_" denzT+ DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
CC8)yO t(RJc BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
?2zbZ cKey,UCHAR cMask)
<V~B8C!) {
'fGB#uBt BOOL bAdded=FALSE;
8NJxtT~0c~ for(int index=0;index<MAX_KEY;index++){
aA|<W
g if(hCallWnd[index]==0){
,3As
Ng hCallWnd[index]=hWnd;
P,}cH;w6Ck HotKey[index]=cKey;
P~H?[
; HotKeyMask[index]=cMask;
m'b9 f6 bAdded=TRUE;
;
m]KKB KeyCount++;
2.>WR~\ break;
[K=M;$iQ }
o;zU;pkB }
\Xr
Sn_p- return bAdded;
a
At<36{? }
<U]!1 //删除热键
6Kbc:wlR BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
$Sx(vq6( {
!'jZ
!NFO BOOL bRemoved=FALSE;
6VsgZ"Il for(int index=0;index<MAX_KEY;index++){
RI[=N:C^ if(hCallWnd[index]==hWnd){
p";5J+?( if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
JdK'~-L hCallWnd[index]=NULL;
1LK` HotKey[index]=0;
L2,.af6+ HotKeyMask[index]=0;
b5@sG^ bRemoved=TRUE;
&qjc+-r{l KeyCount--;
.S{FEV break;
jGSY$nt9 }
F+m%PVW: }
9Ev<t\B }
"?X,);5S return bRemoved;
[B,w\PLub }
t4P`#,:8 <l.l6okp ^7Hwpn7E DLL中的钩子函数如下:
Sf>#Zqj/ hb. ^& LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
^ 5D%)@~ {
AbExJ~JV\g BOOL bProcessed=FALSE;
n6xJ if(HC_ACTION==nCode)
k',#T932x1 {
_u{z$; if((lParam&0xc0000000)==0xc0000000){// 有键松开
[pRRBMho switch(wParam)
N8E {
3!u`PIQv case VK_MENU:
z|$M,?r' MaskBits&=~ALTBIT;
w:VD[\h break;
(Qcd !! case VK_CONTROL:
;H4 s[#K MaskBits&=~CTRLBIT;
A/c #2 break;
Q;xJ/4 Z" case VK_SHIFT:
r6QshCA" MaskBits&=~SHIFTBIT;
+Zg@X.z break;
E Xxv default: //judge the key and send message
ogvB{R break;
t+ vz=` }
67g"8R#.V for(int index=0;index<MAX_KEY;index++){
YW2h#PV6_ if(hCallWnd[index]==NULL)
(uVL!%61k continue;
&~aS24c if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
N`HiNb
[ {
4Jf9N' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
F;L8FL- bProcessed=TRUE;
0NF=7 j }
sR4B/1'E }
&<LBz| }
<2SWfH1> else if((lParam&0xc000ffff)==1){ //有键按下
6E#znRi6IE switch(wParam)
CUN1.i<pk8 {
cSTF$62E case VK_MENU:
p/U{*i]t MaskBits|=ALTBIT;
.%EYof break;
:2.<JUDM case VK_CONTROL:
mKBO<l{S MaskBits|=CTRLBIT;
k2O3{xIjc break;
"WzKJwFr case VK_SHIFT:
!pZ<{|cH MaskBits|=SHIFTBIT;
PbnAY{J break;
RcC5_@W default: //judge the key and send message
q5G`q&O5 break;
ALQ-aXJ }
/Nkxb& for(int index=0;index<MAX_KEY;index++){
+[rQf<* if(hCallWnd[index]==NULL)
?C`r3 continue;
.1+I8qj if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Ms#rvn!J {
TwsI8X SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
fC".K
Yjp bProcessed=TRUE;
<aLS4 }
O6ph_$nt. }
CTS1."kx1 }
;0U*N &
f if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
k1.%ZZMM for(int index=0;index<MAX_KEY;index++){
uBl&{$< if(hCallWnd[index]==NULL)
Wu" 1M^a continue;
TuEM if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
JW!.+
Q SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
fy$?~Ji& //lParam的意义可看MSDN中WM_KEYDOWN部分
&1Cs' }
%!r.)Wx|2 }
/,_m\JkwL }
Qvty;2$o@ return CallNextHookEx( hHook, nCode, wParam, lParam );
6?Kl L [~ }
!6l*Jc3 ,5x#o 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
?;y-skh 5DDSo0E BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
'J$@~P BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
$
x:N/mMu` QWnGolN 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:
dr(-k3ex L9<\vJ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
Vm[F~2+HX {
;?k<L\zaw if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
e=l:!E10 {
)o<^6Ic%7 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
''(rC38 SaveBmp();
51`&%V{daL return FALSE;
Jt[,V*:# }
L$i:~6 …… //其它处理及默认处理
<:Mz2Rg }
`KN>0R2k F(#?-MCs lKB9n}P 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
qDG2rFu&[ 7FJ4;HLQ 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
.$H"j> k qL.ZR 二、编程步骤
3C<G8*4);/ */l;e<E 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";
w|6/ i/X &y}7AV 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
/OWwC%tM/ {x?qz~W 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;
^~.AV]t| OxYAM,F 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;
5 ty2e`~K eb}P/ 5、 添加代码,编译运行程序。
1C8xJ 6F l'/`2Y1 三、程序代码
a_V\[V{R= GdcXU:J / ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
e`s1z|h #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
/wLGf]0 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
$TmEVC^0 #if _MSC_VER > 1000
",.f
#pragma once
ZX` \so,&, #endif // _MSC_VER > 1000
Gk{ 'U #ifndef __AFXWIN_H__
:Y\ ~[Y #error include 'stdafx.h' before including this file for PCH
5, ,~k= #endif
jwT` Z #include "resource.h" // main symbols
A4!X{qUT- class CHookApp : public CWinApp
fJ[ ^_,O {
C[<}eD4bV public:
UuWIT3W>% CHookApp();
`z\hQ%1!F // Overrides
88~Nrl=co // ClassWizard generated virtual function overrides
y\Aa;pL)RQ //{{AFX_VIRTUAL(CHookApp)
3"7Q[9Oj public:
-0d9,,c virtual BOOL InitInstance();
1hY| XZ%qd virtual int ExitInstance();
L@{'J //}}AFX_VIRTUAL
wn5OgXxG< //{{AFX_MSG(CHookApp)
<rj'xv // NOTE - the ClassWizard will add and remove member functions here.
J)>DsQ+Cj // DO NOT EDIT what you see in these blocks of generated code !
!iKW1ks //}}AFX_MSG
M5ZH6X@5 DECLARE_MESSAGE_MAP()
]]PNYa };
Kf:!tRE LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
P}}G9^ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
z3uR1vF' BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
+PjTT6 BOOL InitHotkey();
A7Ql%$v7^ BOOL UnInit();
qU!dg #endif
{&n- @$? ZOEe -XW //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
?Ts]zO%%Z #include "stdafx.h"
f?UI+TU #include "hook.h"
+d6onO{8 #include <windowsx.h>
R%WY!I8C #ifdef _DEBUG
TRGpE9i #define new DEBUG_NEW
ksv] #undef THIS_FILE
S&`6pN static char THIS_FILE[] = __FILE__;
@KTuG ?. #endif
^YLC {V #define MAX_KEY 100
u2oS Ci #define CTRLBIT 0x04
[f_^BU& #define ALTBIT 0x02
}ssV"5M #define SHIFTBIT 0x01
/aI@2] |~ #pragma data_seg("shareddata")
v0\l~_|H HHOOK hHook =NULL;
.t_t)'L UINT nHookCount =0;
&s+l/;3 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
;d6Dm)/( static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
N:<$]x> static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
eTa_RO,x static int KeyCount =0;
t(#9.b`W) static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
?}KRAtJ8 #pragma data_seg()
&>zH.6%$ HINSTANCE hins;
@wR3L:@ void VerifyWindow();
i//H5D3 BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
dipfsH]p //{{AFX_MSG_MAP(CHookApp)
%
"(&a'B // NOTE - the ClassWizard will add and remove mapping macros here.
9-;-jnDy // DO NOT EDIT what you see in these blocks of generated code!
<gF]9%2E //}}AFX_MSG_MAP
5bLNQz\WJ END_MESSAGE_MAP()
bTum|GWf |8k1Bap`z CHookApp::CHookApp()
mXRkR.zu+ {
|{ N{VK // TODO: add construction code here,
s * (a // Place all significant initialization in InitInstance
,.<mj !YE }
XRV]u|w=g axnlI*! CHookApp theApp;
i(j/C LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
;:6\w!fc {
1"H;Tr| BOOL bProcessed=FALSE;
n~ *|JJ*` if(HC_ACTION==nCode)
NIs 7v {
E8!`d}\# if((lParam&0xc0000000)==0xc0000000){// Key up
fQfn7FaW_\ switch(wParam)
[|Qzx w9 {
VfcIR( case VK_MENU:
*BsK6iVb MaskBits&=~ALTBIT;
O52/fGt break;
UMGiJO\yH case VK_CONTROL:
C8-7XQ=B:b MaskBits&=~CTRLBIT;
MKBDWLCB break;
w)EYj+L case VK_SHIFT:
(GC]= MaskBits&=~SHIFTBIT;
ok\-IU? break;
?9~^QRLT default: //judge the key and send message
*5feB# break;
Cy;UyZ }
y\skke] for(int index=0;index<MAX_KEY;index++){
>bW=oTFz if(hCallWnd[index]==NULL)
{ M**a continue;
)]P(!hW. if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
c~R'`Q {
%B$ftsYXmu SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
*{ rorir bProcessed=TRUE;
P{o)Ir8Tt }
ZwUBeyxS=c }
+M-tYE
5n }
hE&6;3"> else if((lParam&0xc000ffff)==1){ //Key down
zZ%[SW&vC switch(wParam)
>.
K {
vJ&_-CX case VK_MENU:
~Gfytn9x.; MaskBits|=ALTBIT;
GLf!i1Z break;
?EFRf~7JP case VK_CONTROL:
_WEJ,0*#' MaskBits|=CTRLBIT;
hY&Yp^"}]^ break;
^-"Iwy case VK_SHIFT:
uPfz'|, MaskBits|=SHIFTBIT;
OFtaOjsyUa break;
=|?`5!A default: //judge the key and send message
od)TQSo break;
QY;(Ny/(y }
KfiSQ!{ for(int index=0;index<MAX_KEY;index++)
9S%5Z> {
1/97_:M0~F if(hCallWnd[index]==NULL)
vD#U+ continue;
6|eqQ+(A if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
E
f\|3D_ {
+pR,BjY SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
YmC}q20; bProcessed=TRUE;
t;o\"H }
<wSJK }
AX v
q~XE }
w
% Hj' if(!bProcessed){
n[jXqFm!` for(int index=0;index<MAX_KEY;index++){
H,%bKl# if(hCallWnd[index]==NULL)
$'V^_|EL7 continue;
U6&`s%mIa if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
XM:BMd| SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
I/(U0`% }
U"r*kO% }
Jx+6Kq( }
$]DuO1H./ return CallNextHookEx( hHook, nCode, wParam, lParam );
pbx*Y`v }
UVw^t+n {?`rGJ{f BOOL InitHotkey()
Ic0Sb7c {
bL7Gkbs&| if(hHook!=NULL){
a}@b2Wc* nHookCount++;
SMZ*30i return TRUE;
XY'=_5t }
'/I`dj else
k{+cFG\C& hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
JQKXbsXS if(hHook!=NULL)
b\"F6TF: nHookCount++;
$V87=_} return (hHook!=NULL);
L/u|90)L }
LLgw1 @-D BOOL UnInit()
J&aN6 l? {
@}q, ';H7 if(nHookCount>1){
*O$|,EsY nHookCount--;
LgF?1? return TRUE;
]0R*F30] }
i*|HN"! BOOL unhooked = UnhookWindowsHookEx(hHook);
nFlN{_/ if(unhooked==TRUE){
Qf_N,Bq{a nHookCount=0;
hF-QbO hHook=NULL;
4XAB_Q }
h{)m}"n<R return unhooked;
M]o]D;N~l }
z-
q.8~Z Zz} o t BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
{qw'gJmX {
sK%b16# BOOL bAdded=FALSE;
;>7~@
K for(int index=0;index<MAX_KEY;index++){
\IQG%L{ if(hCallWnd[index]==0){
;l%xjMcU hCallWnd[index]=hWnd;
a~yiLq HotKey[index]=cKey;
?eTZ>o.p/ HotKeyMask[index]=cMask;
e;vI XJE bAdded=TRUE;
|}d^lQ9 KeyCount++;
.M:&Aj)x16 break;
zYM2`(Z
5B }
_gVihu }
4]1/{</B| return bAdded;
ZW?h\0Hh }
vL _yM o+x%q<e;c BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
{U-z(0 {
}h1BAKg BOOL bRemoved=FALSE;
h_t`)]- for(int index=0;index<MAX_KEY;index++){
v^eAQoFLhN if(hCallWnd[index]==hWnd){
{ 5 r]G if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ox SSEs hCallWnd[index]=NULL;
HxK'u4I HotKey[index]=0;
l8E))oz1T HotKeyMask[index]=0;
Q7u|^Gu,5 bRemoved=TRUE;
npeL1zO-$ KeyCount--;
t!wbT79/ break;
>yc),]1~ }
Vw;iE=L }
f IV"U }
&DGqY5= return bRemoved;
"`K_5"F }
\@PMj"p|: Zs^zD;zU void VerifyWindow()
YAR$6& {
VP< zOk7 for(int i=0;i<MAX_KEY;i++){
~98q1HgS]D if(hCallWnd
!=NULL){
C2LG@iCIE
if(!IsWindow(hCallWnd)){ $Ud9v 4
hCallWnd=NULL; V@+sNM
HotKey=0; X,@nD@
HotKeyMask=0; 4+qo=i
KeyCount--; G>^= Bm_$
} R)d_0Ng
} 7/&t