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:
>u4e:/5]
2tbqmWw/s 一、实现方法
7'8O*EoB' bo*q{@Ue 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:
m!2Dk#t C{ti>'"V #pragma data_seg("shareddata")
x)?\g{JH HHOOK hHook =NULL; //钩子句柄
ms{R|vU%b UINT nHookCount =0; //挂接的程序数目
+/X'QB$R static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
=QC^7T static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
g|zK%tR_P static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
c[YjGx static int KeyCount =0;
zm"\D
vN) static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
v]J# SlF #pragma data_seg()
7 dzE"m Stc\P]%d 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
j~8+,: 9=o
b: DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
7^iAc6QSy3 *Q>:|F[vM BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
j*zK"n cKey,UCHAR cMask)
M'HOw)U {
b1#=q0Zl BOOL bAdded=FALSE;
t#q>U%! for(int index=0;index<MAX_KEY;index++){
J#kdyBmuO if(hCallWnd[index]==0){
w*
I+~o- hCallWnd[index]=hWnd;
c]]F`B HotKey[index]=cKey;
ZX0c_Mk= HotKeyMask[index]=cMask;
j{^(TE bAdded=TRUE;
s/^k;qw KeyCount++;
VZ,T`8" break;
&8pXkD#A }
3/AUV%+ }
.$k"+E return bAdded;
ZFON]$Zk }
IBqY$K+l //删除热键
/OP*ARoC21 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
'l:2R,cP {
Cm4*sN.&) BOOL bRemoved=FALSE;
A1q^E(}O for(int index=0;index<MAX_KEY;index++){
P&GZe/6Y if(hCallWnd[index]==hWnd){
p4t)Z#0 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
sfV.X:ev hCallWnd[index]=NULL;
=l(JJ HotKey[index]=0;
*p3P\ H^5 HotKeyMask[index]=0;
SSXS bRemoved=TRUE;
64lEB>VNm KeyCount--;
eTc`FXw` break;
ETOc4hMO }
hkJZqUA }
vo$66A }
mig3.is return bRemoved;
k)s 7Ev* }
78)^vvn5~ dO[4}FZ$ ]KeNC)R DLL中的钩子函数如下:
_p&$X w#T,g9 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
62jA {
wDO5Zew! BOOL bProcessed=FALSE;
8:% R|b if(HC_ACTION==nCode)
/6zpVkV {
t {"iIz_S if((lParam&0xc0000000)==0xc0000000){// 有键松开
m3!M L>nLt switch(wParam)
GU3/s&9 {
{ 9 ".o, case VK_MENU:
F29AjW86 MaskBits&=~ALTBIT;
1%"`
=$q% break;
^rwSbM$ case VK_CONTROL:
lc-|Q#$3$ MaskBits&=~CTRLBIT;
X t =bc break;
|esjhf}H>v case VK_SHIFT:
fO^6q1a MaskBits&=~SHIFTBIT;
QNXxpoS# break;
8~E)gV+v default: //judge the key and send message
;#9|l= break;
l*Ei7 |Z }
<&:&qngg for(int index=0;index<MAX_KEY;index++){
)F9r?5}v4x if(hCallWnd[index]==NULL)
%,et$1`g continue;
3+3m`%G if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Ra5'x)m36) {
~ fEs!hl SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
"PaGDhS bProcessed=TRUE;
fR4l4 GU?) }
M7R&J'SAY }
]?(F'& }
n-3j$x1Ne else if((lParam&0xc000ffff)==1){ //有键按下
"5:f{GfO#v switch(wParam)
)V3(nZY {
h(Ed% case VK_MENU:
5iddB $ MaskBits|=ALTBIT;
2nkj;x{H$ break;
EAw#$Aq= case VK_CONTROL:
*t{c}Y&@ MaskBits|=CTRLBIT;
a~F@3Pd break;
;J-Ogt @d7 case VK_SHIFT:
V2{#<d-T! MaskBits|=SHIFTBIT;
4oV_b"xz~ break;
&hN&nH"PC default: //judge the key and send message
Tki/d\!+ break;
~88 Tz+
}
e[mhbFf- for(int index=0;index<MAX_KEY;index++){
^r*%BUU9]% if(hCallWnd[index]==NULL)
^:DhHqvK continue;
Pmlgh&Z if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
QX.6~*m1 {
%K'*P56 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
C'/M/|=Q# bProcessed=TRUE;
_SC }
?vn 0%e868 }
1 {x~iZa }
ZT"|o\G^Q if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
7.
9s.* for(int index=0;index<MAX_KEY;index++){
6'Yn|A if(hCallWnd[index]==NULL)
b+].Uc continue;
|sqo+E if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
H!r
Kz SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
=+}}Sv2 //lParam的意义可看MSDN中WM_KEYDOWN部分
BrH;(*H)8 }
_$\5ZVe }
cJ##K/es }
b2X'AHK S return CallNextHookEx( hHook, nCode, wParam, lParam );
P^3m:bE] }
\1mM5r~ -*hb^MvP 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:
R``VQ `JWYPsWk BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
]~00=nXFM/ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Cxk$"_ }SMJD 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:
cbCE
$ NQ!N"C3u LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
&lPBqw {
Kwl qi]~ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
e*2&s5 #RT {
(Ef2
w[' //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
B_"OA3d_ SaveBmp();
qIGu#zX W return FALSE;
&O6;nJEI }
m/hi~.D9 …… //其它处理及默认处理
y|;8 :b32 }
?FV7|)f AIl$qPKj& oIvnF:c 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
nK jeH@ \gp,Txueb 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
AO}i@YJth o%+A<Ri 二、编程步骤
A_jB|<bjTP
sO6g IPU^ 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
4/2RfDp 5&HT$"H: 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
d@6:|auO a(ux?V)E. 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;
%kZ~xbY Sz|Y$, 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;
85%Pq:E t}XB|h 5、 添加代码,编译运行程序。
otz_nF;E we\b] 三、程序代码
yxC Ml. n4vXm ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
k>:/D #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
nI*(a: #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
W7*_ T] #if _MSC_VER > 1000
^3WIl] #pragma once
TDl!qp @ #endif // _MSC_VER > 1000
!#c[~erNZ #ifndef __AFXWIN_H__
lbKv #error include 'stdafx.h' before including this file for PCH
Tw`c6^%^y #endif
iM/*&O} #include "resource.h" // main symbols
tB ,. class CHookApp : public CWinApp
I(^jOgYU {
d4p{5F7]^ public:
^A11h6I CHookApp();
u+z .J4w // Overrides
Ufaqhh // ClassWizard generated virtual function overrides
1o|0x\ q //{{AFX_VIRTUAL(CHookApp)
6VH90KAT public:
v?YdLR virtual BOOL InitInstance();
e7XsyL'|p virtual int ExitInstance();
eg$5z
Z //}}AFX_VIRTUAL
{{.sEi* //{{AFX_MSG(CHookApp)
Y( 1L>4 // NOTE - the ClassWizard will add and remove member functions here.
z;bH<cQ // DO NOT EDIT what you see in these blocks of generated code !
6bbZ<E5At //}}AFX_MSG
:7$\X[ DECLARE_MESSAGE_MAP()
^_*jp[!`b$ };
SRt$4EL21 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
V@#*``M,3 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
*R_'$+ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
>9o,S3 BOOL InitHotkey();
oh7#cFZZ0 BOOL UnInit();
nr<WO~Xw~ #endif
hl6,#2$ Y7*(_P3/ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
6(N.T+;] #include "stdafx.h"
Gd30Be2gd #include "hook.h"
#1QX!dK+ #include <windowsx.h>
sR"zRn #ifdef _DEBUG
+CnyK(V #define new DEBUG_NEW
|D;_:x9 #undef THIS_FILE
9N~8s6Ob static char THIS_FILE[] = __FILE__;
U^M@um M #endif
E8T"{
R80 #define MAX_KEY 100
#<a_: m)@ #define CTRLBIT 0x04
)(h&Q?
Ar #define ALTBIT 0x02
%~#!NX #define SHIFTBIT 0x01
Y!++CMzU #pragma data_seg("shareddata")
Y<p zy8z HHOOK hHook =NULL;
1DEO3p UINT nHookCount =0;
<a8#0ojm static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
WF ?/GN static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
O`wYMng) static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
qDby!^ryc static int KeyCount =0;
n0rerI[R static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
S2J#b"Y #pragma data_seg()
fKL'/?LD] HINSTANCE hins;
)"(V*Z void VerifyWindow();
GXOFk7> BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
ps"/}u l //{{AFX_MSG_MAP(CHookApp)
to99_2 // NOTE - the ClassWizard will add and remove mapping macros here.
sg3h i"Im // DO NOT EDIT what you see in these blocks of generated code!
N<KKY"?I' //}}AFX_MSG_MAP
k~0#'I9 END_MESSAGE_MAP()
=4frP*H? `4VO&lRm CHookApp::CHookApp()
BN+V,W {
R&6n?g6@/V // TODO: add construction code here,
N4I^.k<-A // Place all significant initialization in InitInstance
^G}# jg. }
>Hdjsu5{N vP3K7En CHookApp theApp;
=ud`6{R LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
M*d-z {
kRmj"9oA BOOL bProcessed=FALSE;
#V<`U:. if(HC_ACTION==nCode)
n_<mPU {
HA$Y1} if((lParam&0xc0000000)==0xc0000000){// Key up
r#LnDseW switch(wParam)
y._'K+nl {
sW;7m[o case VK_MENU:
"#*Nnt MaskBits&=~ALTBIT;
EKcC+g break;
%
2I case VK_CONTROL:
!+m@AQ:, MaskBits&=~CTRLBIT;
~k9O5S{ break;
jmkRP"ZnA case VK_SHIFT:
C=>B_EO MaskBits&=~SHIFTBIT;
q&u$0XmV break;
}C=Quy%Z< default: //judge the key and send message
(l
Lu?NpIi break;
^fkCyE;= }
,/~[S for(int index=0;index<MAX_KEY;index++){
)yHJ[ if(hCallWnd[index]==NULL)
e &d3SQ% continue;
E::L?#V if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
m])Lw@#9W {
joe9.{ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
2*+3RrJ bProcessed=TRUE;
LFCTr/, }
2bWUa~%B }
F
vj{@B! }
+Qt[1Xq else if((lParam&0xc000ffff)==1){ //Key down
]x1p!TSU switch(wParam)
,,S9$@R {
K6E}";; case VK_MENU:
<# >Oy&E MaskBits|=ALTBIT;
"cwR^DoD& break;
?p(kh^ z case VK_CONTROL:
=KV@&Y^x4 MaskBits|=CTRLBIT;
?~!tM}X0:3 break;
WS5A Y @(~ case VK_SHIFT:
-<6v:Z MaskBits|=SHIFTBIT;
Ru:n~77{ break;
KL
"Y!PN: default: //judge the key and send message
1:_=g #WH break;
p:B
]Ft }
G OpjRA@ for(int index=0;index<MAX_KEY;index++)
Po> e kz_E {
]5N zK=2{ if(hCallWnd[index]==NULL)
Z
#EvRC continue;
n<E.Em1 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Te+^J8 {
H-185]7 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Yr+d1( bProcessed=TRUE;
\4aKLr }
Y:wF5pp; }
!#. \QU| }
h77IWo6% if(!bProcessed){
9[kX/#~W* for(int index=0;index<MAX_KEY;index++){
8\DME if(hCallWnd[index]==NULL)
w$b~x4y% continue;
0F^]A"kF if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
7ZQ'h3K SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
c -w0 }
`0?^[;[u[ }
9<v}LeX }
y5_XHi@u~o return CallNextHookEx( hHook, nCode, wParam, lParam );
bjlkX[{}I }
or7pJy%4" 7gm:ZS BOOL InitHotkey()
z`OkHX*+2| {
ZY)%U*jWU if(hHook!=NULL){
mY`@' nHookCount++;
3 q"7K return TRUE;
b{BaQ>.(` }
Yc
d3QRB else
rhIGOk1k hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
;,dkJ7M if(hHook!=NULL)
iOll WkF nHookCount++;
Mm.Ql return (hHook!=NULL);
%]#VdS|N }
AeaPK BOOL UnInit()
Evkt_vvf {
rCE;'? Y if(nHookCount>1){
*qG$19b nHookCount--;
8[M*
x3 return TRUE;
`dO}L }
}'TTtV:Q BOOL unhooked = UnhookWindowsHookEx(hHook);
Jh?z=JY if(unhooked==TRUE){
|YRY!V_w nHookCount=0;
2A>C+Y[7\ hHook=NULL;
y^G>{?Tha }
3%2jwR return unhooked;
PPj[;(A }
xZyeX34{M; odpUM@OAW BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
|Ytg {
6b<+8w BOOL bAdded=FALSE;
C3)|<E for(int index=0;index<MAX_KEY;index++){
/VO^5Dnb if(hCallWnd[index]==0){
*> KHRR<N hCallWnd[index]=hWnd;
gQ>2!Qc a- HotKey[index]=cKey;
tOM(U-7Z& HotKeyMask[index]=cMask;
Px#$uU bAdded=TRUE;
(f~gEKcB2u KeyCount++;
uB;_vC break;
/[iG5~G }
69/?7r }
\vVSh return bAdded;
t:=k)B }
H_Os4} Yx),6C3 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
$/paEn" {
_88QgThb BOOL bRemoved=FALSE;
uY;R8CiD for(int index=0;index<MAX_KEY;index++){
\?&Au if(hCallWnd[index]==hWnd){
:+:6_x if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
On&L#pf hCallWnd[index]=NULL;
-\Z `z}D HotKey[index]=0;
/EU; ?O HotKeyMask[index]=0;
SdxY>; bRemoved=TRUE;
l{5O5%\, KeyCount--;
4\6:\ break;
q^*6C[G B }
E/mw* c^ }
i3PKqlp. }
2tf6GX: return bRemoved;
xnbsg!`;7W }
N_G4_12( e:OyjG5_ void VerifyWindow()
q}wj}t# {
c
0-w6 for(int i=0;i<MAX_KEY;i++){
A,BEKjR~J if(hCallWnd
!=NULL){ -72j:nk
if(!IsWindow(hCallWnd)){ Yj|]Uff8O
hCallWnd=NULL; x2k*|=$
HotKey=0; Obo _YE
HotKeyMask=0; J>%t<xYf4
KeyCount--; aD ESr?
} .oR3Q/|k]
} [N:BM% FQ
} :6lwO%=F
} #) ]c0]p
Jq
.L:>x
BOOL CHookApp::InitInstance() *Hs*,}MS
{ eg3L:rk_
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 2+'|kt2
hins=AfxGetInstanceHandle(); ,J(lJ,c
InitHotkey(); S0LszW)e
return CWinApp::InitInstance(); RtC'v";6
} [M:S`{SbY
g19S
int CHookApp::ExitInstance() #3 bv3m
{ ArzDI{1
VerifyWindow(); @B`Md3$7
UnInit(); P^[/Qi}j
return CWinApp::ExitInstance(); AmcC:5
} Q\9K2=4
wqy^8N[K]
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file %{C)1*M7
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) >SDpuG&>
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ f^9&WT
#if _MSC_VER > 1000 2a `J%A
#pragma once l>&sIX
#endif // _MSC_VER > 1000 .Xd0
Q=1h
8!zbF<W9
class CCaptureDlg : public CDialog G {b:i8}l
{ )~
z Z'^
// Construction L.B~ax.|Z
public: UFEN y."P
BOOL bTray; kdcQw7G
BOOL bRegistered; zOGR+Gq_Z
BOOL RegisterHotkey(); m^I,}1H4
UCHAR cKey; \c7>:DH
UCHAR cMask; tln1eN((q
void DeleteIcon(); 6OB" ,
void AddIcon(); ai;\@$ cq
UINT nCount; 6>DLp}d
void SaveBmp(); Qhy#r
CCaptureDlg(CWnd* pParent = NULL); // standard constructor rLF*DB3l
// Dialog Data #?&0D>E?k
//{{AFX_DATA(CCaptureDlg) r{[OJc!
enum { IDD = IDD_CAPTURE_DIALOG }; n &}s-`D
CComboBox m_Key; s[AA7>]3
BOOL m_bControl; 1R*=.i%W
BOOL m_bAlt; 6D/ '`
BOOL m_bShift; o8z)nOTO;
CString m_Path; q`Q}yE>9
CString m_Number; Y~qb;N\
//}}AFX_DATA \VN=Ef\E
// ClassWizard generated virtual function overrides 7=k^M, a
//{{AFX_VIRTUAL(CCaptureDlg) |LmSWy*7
public: p=gX!4,9<
virtual BOOL PreTranslateMessage(MSG* pMsg); S "
pI
protected: kuKa8c
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support -BhTkoN)
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); s@!$='|
//}}AFX_VIRTUAL :ejJV
6.
// Implementation !>g:Si"
protected: ,X/-
HICON m_hIcon; +K{LQsR]
// Generated message map functions x(~<