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:
~W@dF~r
SGKAx<U 一、实现方法
`n>/MY cyNE} 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:
Y1cL dQn $#V'm{Hh #pragma data_seg("shareddata")
4&E"{d
> HHOOK hHook =NULL; //钩子句柄
|5flvkid UINT nHookCount =0; //挂接的程序数目
>33=0< static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
_`gF%$]b static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
Mmz;
uy_ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
T#*,ME7|m static int KeyCount =0;
K+Him]
b static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
yl$Ko #pragma data_seg()
1ZFKLI`V 1(;{w+nM 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。
r(^00hvH |?KYY0 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:
D:k< , { fV+a0=Z BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
"'5(UiSFz cKey,UCHAR cMask)
=R0f{&"i {
C2<TR PT BOOL bAdded=FALSE;
[60y.qE for(int index=0;index<MAX_KEY;index++){
7c_2.T@4 if(hCallWnd[index]==0){
r 2:{r`ocM hCallWnd[index]=hWnd;
8YZ9 HotKey[index]=cKey;
bB4FjC': HotKeyMask[index]=cMask;
2>jk@~Z1:u bAdded=TRUE;
+xuv+mo KeyCount++;
:[@rA;L break;
/J^dzvH }
23CvfP }
tE0{ae return bAdded;
Nd(3q]{ }
0^*,E/}P& //删除热键
;[o:VuTs BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
K2*rqg {
\(LD<-a BOOL bRemoved=FALSE;
fDYTupKXH for(int index=0;index<MAX_KEY;index++){
]DnAW'm if(hCallWnd[index]==hWnd){
O#.YTTj if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
gI7*zR4D hCallWnd[index]=NULL;
o;c"-^> HotKey[index]=0;
(pH)QG HotKeyMask[index]=0;
{n>.Y-= bRemoved=TRUE;
v
RD/67 KeyCount--;
38sLyoG=i break;
'7oR|I }
l4DBGZB }
q=^;lWs4 }
glC,E> return bRemoved;
(?A
c`H }
4!14:mq f:3cV(mC e
oE)Mq DLL中的钩子函数如下:
dQ;8,JzIw& Dt!KgI3 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
$mK;{9Z
{
~AWn 1vFc BOOL bProcessed=FALSE;
1Z 0Qkd( if(HC_ACTION==nCode)
<<
=cZ.HP {
hXFT(J= if((lParam&0xc0000000)==0xc0000000){// 有键松开
iUz?mt;k switch(wParam)
1E$\&*( {
vcW(?4e case VK_MENU:
ZeG4z({af MaskBits&=~ALTBIT;
UD14q~ (1Z break;
=m<b+@?T case VK_CONTROL:
io\t>_ MaskBits&=~CTRLBIT;
EkV#i
break;
.hckZx / case VK_SHIFT:
NcbW"Qv3 MaskBits&=~SHIFTBIT;
Z>UM gu3c break;
;8=Bee4 default: //judge the key and send message
C_3,|Zq?| break;
3` IR
^ }
!hJ!ck]M for(int index=0;index<MAX_KEY;index++){
6
JI8l`S if(hCallWnd[index]==NULL)
;a|%W4 " continue;
0++RxYFCL if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
&@xm< A\S {
?Xpk"N7 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
j#3IF *" bProcessed=TRUE;
q-^{2.ftcx }
fhn$~8[_A }
6 _V1s1F }
}#tbK 2[ else if((lParam&0xc000ffff)==1){ //有键按下
dB~A4pZa switch(wParam)
;^JMX4[ {
3\]j4*i! case VK_MENU:
cRs\()W MaskBits|=ALTBIT;
$$Tf1hIg break;
DI(X B6 case VK_CONTROL:
]Ky`AG`2~ MaskBits|=CTRLBIT;
N MkOx$ break;
TP| ogF? case VK_SHIFT:
}@.@k6`n MaskBits|=SHIFTBIT;
(mbm',%- ( break;
KtJc9dnX default: //judge the key and send message
jHob{3 break;
CqWO 0 }
`_.:O,^n^ for(int index=0;index<MAX_KEY;index++){
y%9Hu if(hCallWnd[index]==NULL)
[c;0eFSi2 continue;
63'%+ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
cjtcEW {
1Z?uT[kR SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
]2ab~
gr bProcessed=TRUE;
!r6Yq,3 }
;9#%E }
SnX)&>B }
P_H2[d&/>D if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
o+{7"Na8[ for(int index=0;index<MAX_KEY;index++){
^r<l#D, if(hCallWnd[index]==NULL)
uzb|yV'B continue;
} PL{i if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
[xb'73 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
t%,:L.?J# //lParam的意义可看MSDN中WM_KEYDOWN部分
OW6dK#CFt }
Jj0:p" }
+t-_FbFh3D }
%jx<<hW return CallNextHookEx( hHook, nCode, wParam, lParam );
ci+ajON }
?ecR9X k ~("bpS#ZgD 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:
-ert42fN ,+Ocb-* BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
3=?,Dv0P BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
[uJS.`b )x?)v#k 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:
W@zxGH$z> 2^=.f?_YR LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
`tuGy}S2
{
U)iBeYW: if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
.i )n1 {
E:uTjXt //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
yW*,Llb5 SaveBmp();
!K2QD[x return FALSE;
Piw i }
GBBp1i
…… //其它处理及默认处理
ru/{s3 }
#N|JC d_ ,y-!h@( ?
47"$=G 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。
'
Qlj"U V@y&n1?6 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。
(+xT5 2 mBB"e"o 二、编程步骤
;*+H& t+pA9^$[` 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
`WMU'ezF Z;tWV%F5 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
\R-'<kN.* JSylQ201 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
{md5G$*% MLiaCG; 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;
q-@&n6PEOZ p Djt\R<f 5、 添加代码,编译运行程序。
y\CxdTs -s)h
?D 三、程序代码
Gr}NgyT<!D B+jh|@- ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
8$ RiFD, #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
B>I:KGkV #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
_d^d1Q}V #if _MSC_VER > 1000
+BhJske #pragma once
S{)K_x #endif // _MSC_VER > 1000
<gFisc/#r #ifndef __AFXWIN_H__
^xScVOdP #error include 'stdafx.h' before including this file for PCH
L&=r-\.ev #endif
u(hJyo} #include "resource.h" // main symbols
1`s^r+11: class CHookApp : public CWinApp
GjN6Af~} {
92C; a5s public:
7hLh} CHookApp();
g HxR w // Overrides
E{^W- // ClassWizard generated virtual function overrides
a3A3mBw //{{AFX_VIRTUAL(CHookApp)
e7-IqQA{3C public:
v>mK~0.$ virtual BOOL InitInstance();
u"wWekB virtual int ExitInstance();
t.\Pn4 //}}AFX_VIRTUAL
eR`Q7]j] - //{{AFX_MSG(CHookApp)
CGb4C(%-7 // NOTE - the ClassWizard will add and remove member functions here.
c4Q9foE
// DO NOT EDIT what you see in these blocks of generated code !
&sYxe:H //}}AFX_MSG
xTH3g^E DECLARE_MESSAGE_MAP()
}7xcHVO8- };
<dVJV?i; LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
Wl+spWqW BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
W1LR ,:$ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
5G`fVsb BOOL InitHotkey();
AOwmPHEL BOOL UnInit();
IAN={";p #endif
([^f1;ncm gLFTnMO //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
JvP>[vb #include "stdafx.h"
<R~;|&o,$ #include "hook.h"
#W.vX=/* #include <windowsx.h>
<u],R.S) #ifdef _DEBUG
Bva2f:)K| #define new DEBUG_NEW
sO(4F8cpU #undef THIS_FILE
VfDa>zV3 static char THIS_FILE[] = __FILE__;
zMO#CZ t #endif
T-+ uQ3 #define MAX_KEY 100
'n\P S,[1R #define CTRLBIT 0x04
Hr7pcz/#l #define ALTBIT 0x02
L(k`1E #define SHIFTBIT 0x01
=:6B`,~C #pragma data_seg("shareddata")
QoxQ"r9Wh HHOOK hHook =NULL;
9d( M%F UINT nHookCount =0;
H;q[$EUNb static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
Ro `Xs.X static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
=1VZcLNt static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
rQ2TPX<?a static int KeyCount =0;
!mB
`F C static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
>#gDk K #pragma data_seg()
.N#KW HINSTANCE hins;
vg"*%K$a void VerifyWindow();
qzO5p=} BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
suFk<^3 //{{AFX_MSG_MAP(CHookApp)
WIAukM8~ // NOTE - the ClassWizard will add and remove mapping macros here.
jffNA^e // DO NOT EDIT what you see in these blocks of generated code!
0jPUDkH* //}}AFX_MSG_MAP
^ZRZ0:rZ END_MESSAGE_MAP()
cW"DDm
g jP2#w{xq CHookApp::CHookApp()
|b^UPrz)VS {
rce._w } // TODO: add construction code here,
a"t~K // Place all significant initialization in InitInstance
4%_xTo }
4vvQ7e7 R(8?9-w CHookApp theApp;
%XZhSmlf LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
6R$Yh0% {
o-AF_N BOOL bProcessed=FALSE;
]ZW-`U MO if(HC_ACTION==nCode)
7`^Y*:( {
$"MVr5q6 if((lParam&0xc0000000)==0xc0000000){// Key up
-XK;B--c switch(wParam)
3u+i {
EAxdF
u case VK_MENU:
WB<MU:.Vc MaskBits&=~ALTBIT;
yx*<c#Uf break;
ty4R2LnC case VK_CONTROL:
ro3%VA=V MaskBits&=~CTRLBIT;
#N~1Ye break;
nG{o$v_| case VK_SHIFT:
5~im.XfiVx MaskBits&=~SHIFTBIT;
Q00v(6V46 break;
:("@U, default: //judge the key and send message
oe3=QE break;
8|L@-F }
pjoyMHWK for(int index=0;index<MAX_KEY;index++){
,w9|?%S if(hCallWnd[index]==NULL)
DO+~ continue;
]:'] if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
D@ !r?E` {
+9pock SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
DnG9bVm> bProcessed=TRUE;
z}Us+>z+jc }
#T{)y }
^Oeixi@f }
qK2jJ3)> else if((lParam&0xc000ffff)==1){ //Key down
Hi/[ switch(wParam)
V\e1NS {
^,5%fl case VK_MENU:
~Cg7 MaskBits|=ALTBIT;
PX2b(fR8_O break;
iWFtb)3B case VK_CONTROL:
>ke.ZZV? MaskBits|=CTRLBIT;
`_i|\}tl break;
5ug|crX case VK_SHIFT:
j(K)CHH MaskBits|=SHIFTBIT;
FUJ<gqL break;
rwio>4= default: //judge the key and send message
L%<]gJtrO break;
ZJF+./vN }
`g) for(int index=0;index<MAX_KEY;index++)
B*Om\I {
vW!O("\7K< if(hCallWnd[index]==NULL)
W,H=K##6< continue;
K=}Eupn= if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
v&d'ABeT {
2mMi=pv9 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
:PY6J}: bProcessed=TRUE;
1CSGG'J]E }
]\oT({$6B }
1;i|GXY:h }
G-K{ if(!bProcessed){
^;9l3P{ for(int index=0;index<MAX_KEY;index++){
=n_z `I if(hCallWnd[index]==NULL)
4`fV_H.8 continue;
k'PvQl"I if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
a^E>LJL SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Sl'$w4s
}
eOkiB!G. }
nHQ*#&$ }
S#He OPRL return CallNextHookEx( hHook, nCode, wParam, lParam );
@'GPZpbvZ }
9ZatlI, H+]h+K9\7 BOOL InitHotkey()
7/k7V) {
/"m#mhL if(hHook!=NULL){
?z6K/'? nHookCount++;
ja/wI'J< return TRUE;
a#[gNT~[ }
BafNFPc else
2QEH!)lvr hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
"!7Hu7 if(hHook!=NULL)
V"2 G nHookCount++;
+RR6gAma}< return (hHook!=NULL);
?TIi0;h }
72J=_d>+ BOOL UnInit()
Qy}pn=#Q {
Bt5 P][< if(nHookCount>1){
WPlf8* -fQ nHookCount--;
/vi Ic
%= return TRUE;
~Cw7.NA{3 }
Kng=v~)N' BOOL unhooked = UnhookWindowsHookEx(hHook);
< 3*q) VT if(unhooked==TRUE){
S')DAx nHookCount=0;
hA1B C3 hHook=NULL;
6#K.n&=* }
{<gX~./]c return unhooked;
e{Vn{.i,5 }
,F`1VpTd8 xfC$u`e= BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
>.9V`m| {
&V SZ BOOL bAdded=FALSE;
Kb;Pd!Q for(int index=0;index<MAX_KEY;index++){
wgolgof if(hCallWnd[index]==0){
r&+C% hCallWnd[index]=hWnd;
9(}d7y HotKey[index]=cKey;
IR:{ { ( HotKeyMask[index]=cMask;
I@O9bxR? bAdded=TRUE;
P?c V d2Y KeyCount++;
<1m` break;
o"L8n(\ }
*n#
=3D }
%6^nb'l'C return bAdded;
Qb%;
|li }
hNkv lk'Ui PVdN)tG5 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
~)>.%`v& {
ZGI<L BOOL bRemoved=FALSE;
?p 4iXHE for(int index=0;index<MAX_KEY;index++){
V>E7!LIn. if(hCallWnd[index]==hWnd){
c&wiTvRV if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Nge@8 hCallWnd[index]=NULL;
C?]eFKS." HotKey[index]=0;
MZcvr 9y HotKeyMask[index]=0;
Y8IC4:EO bRemoved=TRUE;
J|be'V#]1 KeyCount--;
#902x*Z'c" break;
[q_62[-X }
/L@o.[H }
re#]zc< }
=A{'57yP return bRemoved;
*)I^+zN }
>+.GBf<E Uam%u void VerifyWindow()
3PL0bejaT7 {
}lhk;#r for(int i=0;i<MAX_KEY;i++){
}Y!s:w# if(hCallWnd
!=NULL){ xN}f?
if(!IsWindow(hCallWnd)){ F1B/cd
hCallWnd=NULL; Q*1'k%7
HotKey=0; @p^EXc*|
HotKeyMask=0; q
_K@KB
KeyCount--; QJiH^KY6
} x5pu+-h
} F$1{w"&
} c(FGW7L<
} -r_\=<(
:"Tkl$@,
BOOL CHookApp::InitInstance() 89{;R
{ uR.pQo07y<
AFX_MANAGE_STATE(AfxGetStaticModuleState()); V lO^0r^z
hins=AfxGetInstanceHandle(); FV
aC8Kw
InitHotkey(); z[R
dM#L
return CWinApp::InitInstance(); ZU.E}Rn:
} Bz>f
qvGmJN0
int CHookApp::ExitInstance() COw!a\Jl
{ 0Bkz)4R
VerifyWindow(); Cc`-34/%
UnInit(); K^tc]ZQ
return CWinApp::ExitInstance(); :AqtPV'
} KD+&5=Y
v3t<rv
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file KU0Ad);e
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) ePv`R'#
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_
(V'w5&f(L
#if _MSC_VER > 1000 WS.g`%
#pragma once N=T}
#endif // _MSC_VER > 1000 )8}k.t>'s
WJa7
class CCaptureDlg : public CDialog F:jtzy"
{ 9xw"NcL
// Construction dBovcc
public: 7^M$u\a)U
BOOL bTray; p W5D!z
BOOL bRegistered; |S@
BOOL RegisterHotkey(); #8M^;4N>[
UCHAR cKey; Z(R0IW
UCHAR cMask; _nxu8g]
void DeleteIcon(); C0Fd<