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:
AF=9KWqf
2f%G`4/p 一、实现方法
GAZw4dz ^&AhWm7\ 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:
;Jn"^zT 7#
/c7 #pragma data_seg("shareddata")
C/JeD-JG HHOOK hHook =NULL; //钩子句柄
S~8w- lG! UINT nHookCount =0; //挂接的程序数目
&?],uHB?d static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
$/*6tsR static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
Tr^Egw] static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
fjE static int KeyCount =0;
cmzu
@zq static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
(|6Y1`` #pragma data_seg()
LEq"g7YH W-QBC-
3 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。
nPW?DbH + eYER"E 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:
'E4`qq !Od?69W, $ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
Z$0+jpG_s cKey,UCHAR cMask)
an4^(SY {
V-y"@0%1 BOOL bAdded=FALSE;
},"T,t# for(int index=0;index<MAX_KEY;index++){
ndSM*Fq if(hCallWnd[index]==0){
JJ50(h)U hCallWnd[index]=hWnd;
]%{.zl! HotKey[index]=cKey;
GwOn&EpY! HotKeyMask[index]=cMask;
BEQ$p)
h bAdded=TRUE;
8sDbvVh1F KeyCount++;
ZfpV=DU break;
r((2.,\Z }
>|)ia5# }
P%#EH2J return bAdded;
+h64idM{U }
'`-W!g[
> //删除热键
AhZ`hj BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
$[L8UUHY<8 {
$`2rtF BOOL bRemoved=FALSE;
fZ9EE3 for(int index=0;index<MAX_KEY;index++){
yqy5i{Y if(hCallWnd[index]==hWnd){
)yV|vn if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
N2?o6) hCallWnd[index]=NULL;
Vvth, HotKey[index]=0;
}Htnhom0n HotKeyMask[index]=0;
){AtV&{$ bRemoved=TRUE;
pJ` M5pF KeyCount--;
]x8_f6;D break;
0!D,74r }
L[]*vj }
fn%Gu s~ }
u|!On return bRemoved;
di@4'$5# }
\m3'4# cTA8F"UGD n{>Ge,enP0 DLL中的钩子函数如下:
|H:JwxH .6,+q2tyk, LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
(xp<@- {
dLtSa\2Hn BOOL bProcessed=FALSE;
+E8Itb, if(HC_ACTION==nCode)
[-Zp[ {
E+Jh4$x{ if((lParam&0xc0000000)==0xc0000000){// 有键松开
nkKiYr switch(wParam)
56;(mbW {
^i"C%8 case VK_MENU:
9,?\hBEu MaskBits&=~ALTBIT;
vybQ}dscn break;
yIm@m[B;
case VK_CONTROL:
O/X;(qYd MaskBits&=~CTRLBIT;
U>q&p}z0H break;
AN!MFsk case VK_SHIFT:
Sv*@ 3x MaskBits&=~SHIFTBIT;
ISQC{K']J break;
Kn9O=?Xh; default: //judge the key and send message
uS9:cdH break;
~R;9a"nr }
=h?Q.vad for(int index=0;index<MAX_KEY;index++){
.Z,3:3,] if(hCallWnd[index]==NULL)
@%4MFc0`! continue;
jpL'y1@Ut if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Q^^.@FU"x {
\5+?wpH SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
b-/zt Z@u bProcessed=TRUE;
A)5-w`1 }
4=j,:q }
'Zq$W]i }
j3Ng] @N else if((lParam&0xc000ffff)==1){ //有键按下
u
N%RB$G switch(wParam)
_eB?G {
ep"YGx[V case VK_MENU:
UbBo#(TZ) MaskBits|=ALTBIT;
GVFR^pzO break;
qz|`\^ case VK_CONTROL:
)+^1QL MaskBits|=CTRLBIT;
omxBd#;F$ break;
T&?0hSYt case VK_SHIFT:
@W\y#5"B MaskBits|=SHIFTBIT;
(nhv#&Fd+ break;
br!:g]Vh default: //judge the key and send message
S(7_\8h break;
b&LfL$
}
I91pX<NBf for(int index=0;index<MAX_KEY;index++){
; Nw. if(hCallWnd[index]==NULL)
oDyrf"dl continue;
-Cb<T"7 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
aR }|^ex {
*wNX<R. SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
?
x1"uH bProcessed=TRUE;
^*;{Uj+O~Y }
traJub }
oo{5: }
u3!aKXnv< if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
oB9t&yM for(int index=0;index<MAX_KEY;index++){
A#s`!SNv if(hCallWnd[index]==NULL)
NLe+ continue;
`O-LM e if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
< bHu9D SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
UWdPB2x[ //lParam的意义可看MSDN中WM_KEYDOWN部分
<
V?CM(1C }
B]PTe~n^ }
{VWUK`3 }
)I80Nq
return CallNextHookEx( hHook, nCode, wParam, lParam );
0>
pOP }
B,sv! p+q5 Tct[0B 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:
^ <Z^3c>/ FzOr#(^ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
\V@Hf"=j BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
` [ EzU+ Nw'3gJ: 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:
j@0/\:1(U \`w!v,aM$ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
X-oHQu5 {
#;bpxz1lR9 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
v1hrRf2< {
*}9i@DP1, //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
q&IO9/[dk SaveBmp();
20hF2V return FALSE;
sSLs%)e|: }
Mis t,H7 …… //其它处理及默认处理
2#4_/5(j* }
)oO cV% @MfuV4* zcrLd={ 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。
{;(X#vK}9 LGN,8v<W( 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。
/Kmzi9j+ ETP}mo 二、编程步骤
d*26;5~\ "7R"(.~> 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";
5YJn<XEc @l9qH1
2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
0NLoqq _C9*M6IU 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;
KlgPDV9mg e&dE>m 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;
QN[-XQ>Xt )hH9VGZq( 5、 添加代码,编译运行程序。
IAt;?4 ?^i$} .%W 三、程序代码
q #f
U* :$&%Pxm ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
$tyF(RybG #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
+w Oa #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
,jWMJ0X/N= #if _MSC_VER > 1000
t&UPU&tY #pragma once
/#Y)nyE
#endif // _MSC_VER > 1000
pv2_A #ifndef __AFXWIN_H__
.xT8@] #error include 'stdafx.h' before including this file for PCH
E3gR%t #endif
e";r_J3w #include "resource.h" // main symbols
U;n$ class CHookApp : public CWinApp
[GeJn\C_? {
T>(nc" ( public:
.I{b]6 CHookApp();
\Q"o\:IoIT // Overrides
[>"bL$tlo* // ClassWizard generated virtual function overrides
>;',U<Wd //{{AFX_VIRTUAL(CHookApp)
$AAv%v public:
<{7CS=) virtual BOOL InitInstance();
i^ 9PiP|U virtual int ExitInstance();
v}hmI']yf //}}AFX_VIRTUAL
(yFR;5Fo //{{AFX_MSG(CHookApp)
PMk3b3)Z // NOTE - the ClassWizard will add and remove member functions here.
hd~X c // DO NOT EDIT what you see in these blocks of generated code !
v\*43RL //}}AFX_MSG
CW k#Amt. DECLARE_MESSAGE_MAP()
.3Nd[+[ };
&6A'}9Ch LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
yH>`Kbf T BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
i<|5~tm BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
@psyO]D=j% BOOL InitHotkey();
[B9'/: BOOL UnInit();
NLFSw #endif
"}UJ~ j).
~YHy'. //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
bkkhx,Oi[G #include "stdafx.h"
^4^1)' % #include "hook.h"
*>!O2c #include <windowsx.h>
(#* 7LdZ #ifdef _DEBUG
orn9;|8q #define new DEBUG_NEW
wZVY h #undef THIS_FILE
&eV& +j static char THIS_FILE[] = __FILE__;
W)jO 4,eO #endif
Ktg{-Xl #define MAX_KEY 100
((A]FOIbO #define CTRLBIT 0x04
8YC\Bw #define ALTBIT 0x02
uR{HCZ- #define SHIFTBIT 0x01
u2
a
U0k: #pragma data_seg("shareddata")
FR9<$ HHOOK hHook =NULL;
3*$A;%q UINT nHookCount =0;
@'U9*:}U static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
5Qhu5~,K static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
~dfc static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
6_/691 static int KeyCount =0;
a'w~7y!} static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
R6HMi#eF #pragma data_seg()
R6~x! HINSTANCE hins;
I%^Ks$<" void VerifyWindow();
Pw/Z;N;:V BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
+MPM^ m //{{AFX_MSG_MAP(CHookApp)
g\&[;v
i // NOTE - the ClassWizard will add and remove mapping macros here.
m"\jEfjO // DO NOT EDIT what you see in these blocks of generated code!
?)x>GB(9ZN //}}AFX_MSG_MAP
!YL|R[nDH| END_MESSAGE_MAP()
kf+]bV MZf$8R CHookApp::CHookApp()
XnrOC|P$ {
D/jB. // TODO: add construction code here,
?P[uf // Place all significant initialization in InitInstance
Z^,C><Yt }
5Jq~EB{" i rMZLc6 CHookApp theApp;
* ]~ug%a LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
!)RND 6. {
2yR*<yj BOOL bProcessed=FALSE;
Tx?,]c,(u if(HC_ACTION==nCode)
X-9>;Mb~y {
ep .AW'+ if((lParam&0xc0000000)==0xc0000000){// Key up
T6JN@:8 switch(wParam)
f>ohu^bd {
qd"1KzQWO case VK_MENU:
Ar4E $\W MaskBits&=~ALTBIT;
6lO]V=+ break;
WS8m^~S@\ case VK_CONTROL:
)%x oN< MaskBits&=~CTRLBIT;
cc7*O break;
yC !`6$ case VK_SHIFT:
wXp
A1,i MaskBits&=~SHIFTBIT;
'/U[ ui0{ break;
~n%~ Z|mMF default: //judge the key and send message
Pcut#8?
break;
<y=VDb/ }
/%|JP{ for(int index=0;index<MAX_KEY;index++){
r(iT&uz if(hCallWnd[index]==NULL)
XVAyuuTg\ continue;
4>nY't;0 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
B
PTQm4TN {
W-q2|NK SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
G$pTTT6# bProcessed=TRUE;
w*<XPBi
}
NR-d|`P; }
.GUm3b }
D'Tb= else if((lParam&0xc000ffff)==1){ //Key down
$9<q'hf<w switch(wParam)
J]/TxUE {
%`%oupqm+ case VK_MENU:
;hGC.}X MaskBits|=ALTBIT;
R;&C6S break;
F,Q\_H##x4 case VK_CONTROL:
LnIln[g: MaskBits|=CTRLBIT;
D"0:n. break;
PVHJIB case VK_SHIFT:
*LpEH,J MaskBits|=SHIFTBIT;
6s\niro2 break;
BDSZ ' default: //judge the key and send message
){`s&? M0 break;
Kk1 591' }
HQ~`ha. for(int index=0;index<MAX_KEY;index++)
o&P}GcEIw {
\Km!#: if(hCallWnd[index]==NULL)
e5KsKzu a continue;
3ny>5A!;2 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
}S51yDV G_ {
tFt56/4 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
zY~ bProcessed=TRUE;
ZC 7R f }
~Q"3#4l }
Bz<T{f }
C,7d if(!bProcessed){
bh|M]*Pq for(int index=0;index<MAX_KEY;index++){
s. I%[kada if(hCallWnd[index]==NULL)
B.CUk. continue;
`v3WJ>Q!N? if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
k8H@0p SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
{Vw+~8 }
CsHHJgx }
r_nB-\ }
Qb<i,`SN return CallNextHookEx( hHook, nCode, wParam, lParam );
Qd;P?W6 }
a5=8zO#%g W_l/Jpv!W BOOL InitHotkey()
xY9#ouF {
Fb=(FQ2Y? if(hHook!=NULL){
k#Qav1_ nHookCount++;
bA}9He1 return TRUE;
|57u ; }
1Q\P]
- else
rx2?y3pv hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
%@
UH,Ew if(hHook!=NULL)
hw! l{yv nHookCount++;
C'&)""3d return (hHook!=NULL);
_R&mN\ey5 }
`i5U&K. 7 BOOL UnInit()
NRu_6~^^ {
i
,Cvnp6Lv if(nHookCount>1){
[8|Y2Z\N nHookCount--;
~!UC:&UKo return TRUE;
Ie{98 }
Qt` hUyL BOOL unhooked = UnhookWindowsHookEx(hHook);
/jl{~R#1 if(unhooked==TRUE){
]&6# {I- nHookCount=0;
fB^h2 hHook=NULL;
xIu# }
-!MrG68 return unhooked;
Fj Rt' }
xi['knUi2- J1OZG6|e BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
MmiC%"7wt {
^mxOQc ! BOOL bAdded=FALSE;
rk$&sDc/3 for(int index=0;index<MAX_KEY;index++){
9A_{*E(wd if(hCallWnd[index]==0){
xxjg)rVuy hCallWnd[index]=hWnd;
xC N6? HotKey[index]=cKey;
Xi$( U8J_ HotKeyMask[index]=cMask;
_M'WTe bAdded=TRUE;
kFKc9}7W KeyCount++;
$ N`V%<W break;
ldp
x, }
<xM$^r) }
DfYOGs]@ return bAdded;
3ARvSz@5 }
Gk_%WY* ,=sbK?& BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
pde,@0(Fa {
q#LB 2M BOOL bRemoved=FALSE;
>[t0a"
for(int index=0;index<MAX_KEY;index++){
wM.z/r\p if(hCallWnd[index]==hWnd){
g4b-~1[S if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
_|<kKfd? hCallWnd[index]=NULL;
l-s%3E3 HotKey[index]=0;
PPoQNW HotKeyMask[index]=0;
k=;>*:D% bRemoved=TRUE;
;:<z hO KeyCount--;
|;xm-AM4r break;
A/5??3H }
\8j5b+ }
q5
eyle6 }
#I>
c$dd return bRemoved;
YywiY).]@ }
WM y97*L< +*u'vt? void VerifyWindow()
590.mCm {
&gF*p for(int i=0;i<MAX_KEY;i++){
m]H[$Q if(hCallWnd
!=NULL){ OAigq6[,
if(!IsWindow(hCallWnd)){ Zop3[-
hCallWnd=NULL; x)evjX=q
HotKey=0; A8,9^cQ]
HotKeyMask=0; N:R6
b5
=}
KeyCount--; n(X {|?
} "FuOWI{in
} 2P\k;T(
} U-RR>j
} #'`!*VI
R7)\wP*l5
BOOL CHookApp::InitInstance() 5zk<s`h
{ ? :StFlie
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 7D'-^#S5
hins=AfxGetInstanceHandle(); l^`& Tnzv
InitHotkey(); `Fn"%P!
return CWinApp::InitInstance(); Q`?+w+y7
} x"g-okLN
BdWRm=
int CHookApp::ExitInstance() sk'<K5~
{ Yz<,`w5/6~
VerifyWindow(); V+\L@mz;
UnInit(); nP]tc
return CWinApp::ExitInstance(); Q?"o.T';
} IZ){xI
99QMMup
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file #+VH]7]
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) oJ\)-qSf
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ 7RXTQ9BS
#if _MSC_VER > 1000 ~\vGwy
#pragma once \VY!= 9EV
#endif // _MSC_VER > 1000 jM<=>P
/"~ D(bw0=
class CCaptureDlg : public CDialog ZtzSG@f
{ QuF76&)7
// Construction Xk2M.:3`
public: {?2jvv
BOOL bTray; N=2BrKb)o
BOOL bRegistered; rw CFt6;v
BOOL RegisterHotkey(); rbC4/ 9G\
UCHAR cKey; !T+jb\O_
UCHAR cMask; cL+--$L
void DeleteIcon(); Mn)>G36(
void AddIcon(); Oup5LH!sW
UINT nCount; p#14
void SaveBmp(); bxxazsj^
CCaptureDlg(CWnd* pParent = NULL); // standard constructor ';H"Ye:D=7
// Dialog Data O
&/9wi>!q
//{{AFX_DATA(CCaptureDlg) bIvF5d>9#K
enum { IDD = IDD_CAPTURE_DIALOG }; >Q(+H-w
CComboBox m_Key; ,(1n(FZ
BOOL m_bControl; !yUn|v>&p
BOOL m_bAlt; `
u|8WK:
BOOL m_bShift; CsJ38]=Mt
CString m_Path; 4Sj;38F
.1
CString m_Number; %:jVx
//}}AFX_DATA 2X];zY
// ClassWizard generated virtual function overrides G,jv Mb`+
//{{AFX_VIRTUAL(CCaptureDlg) w)Rtt 9
public: |_<'qh
virtual BOOL PreTranslateMessage(MSG* pMsg); d3nx"=Cy0I
protected: t=-t xnlr<
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support n jfh4}g:
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); y#Cp Vm#!>
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// Implementation {z^6V\O5
protected: WA'&