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:
./0wt+
h<$%y(lP 一、实现方法
opN4@a7l Jc]66
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:
h4hp5M ]>k8v6*= #pragma data_seg("shareddata")
6|3 X*Orn HHOOK hHook =NULL; //钩子句柄
c{?SFwgd UINT nHookCount =0; //挂接的程序数目
$MNJsc^n static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
VnB HQ.C static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
=OPX9oG static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
bXXX-Xc static int KeyCount =0;
JTBt=u{6^ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
HUCJA-OZGL #pragma data_seg()
di9OQ*6a7 ru`U/6n 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
}-XZ1qr *HGhm04F{ DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
`l.bU3C Yjd/ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
-J#RGB{7 cKey,UCHAR cMask)
Y TY(Et1i {
i^A=nsD` BOOL bAdded=FALSE;
8tna<Hx for(int index=0;index<MAX_KEY;index++){
zOFHdd ,"g if(hCallWnd[index]==0){
~ QohP`_ hCallWnd[index]=hWnd;
Eaxsg HotKey[index]=cKey;
QUvSeNSp HotKeyMask[index]=cMask;
c$BH`" <* bAdded=TRUE;
WwtVuc| KeyCount++;
kw gLK@@%1 break;
(3!6nQj-t }
@V5i }
Zby3.=.e return bAdded;
G{>PYLxOb }
d8+@K&z| //删除热键
(#O" BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
H<<t^,E^.t {
+S-60EN*A BOOL bRemoved=FALSE;
=>evkaj for(int index=0;index<MAX_KEY;index++){
" Y^9g/ if(hCallWnd[index]==hWnd){
ST?Rl@4 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
j&Xx{ 4v hCallWnd[index]=NULL;
3tJfh=r=1 HotKey[index]=0;
$0un`&W HotKeyMask[index]=0;
*mJ#|3I< bRemoved=TRUE;
FkuD Gg~a KeyCount--;
6<QC|>p break;
y06**f) }
/BQqg08@L }
|mRlP5 }
5~jz| T}s return bRemoved;
xLi3|^q }
JR15y3F kN{$-v=K aT}Hc5L,b DLL中的钩子函数如下:
v7KBYN i|AWaG) LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
E"S#d&9 {
:#?_4D!r BOOL bProcessed=FALSE;
pOn &D if(HC_ACTION==nCode)
D|m3.si {
.s,04xW\ if((lParam&0xc0000000)==0xc0000000){// 有键松开
BN%cX2j switch(wParam)
'7oCWHq[ {
A/UO cl+N case VK_MENU:
cHT\sJo`l MaskBits&=~ALTBIT;
0!ZaR6 break;
~|O; Sdo= case VK_CONTROL:
+>*=~R MaskBits&=~CTRLBIT;
se2Y:v break;
*n&Sd~Mg case VK_SHIFT:
fjy\Q MaskBits&=~SHIFTBIT;
~1}fL 1~5 break;
Db*b"/] default: //judge the key and send message
-.MJ3 break;
r*$f^T!| }
j
nSZ@u for(int index=0;index<MAX_KEY;index++){
}s@IQay+ if(hCallWnd[index]==NULL)
G/},lUzLg continue;
KA{QGaZ/ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
!^98o:"x {
^lZ7% 6 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
bCC &5b bProcessed=TRUE;
F02TM#Zi }
id :
^| }
JBJ?|}5k4c }
^%Cd@!dk else if((lParam&0xc000ffff)==1){ //有键按下
$^^M&[b- switch(wParam)
vf<Dqy <M. {
Vn{;8hZ:a case VK_MENU:
: fYfXm MaskBits|=ALTBIT;
W?E,"z break;
W=293mME case VK_CONTROL:
Q#ksf
h!D MaskBits|=CTRLBIT;
Y:m8UnT break;
tB`"gC~ case VK_SHIFT:
nFG X2|d MaskBits|=SHIFTBIT;
Op~:z<z break;
is^R8a default: //judge the key and send message
)zz{~Cf break;
noa+h<vGb }
pxedj for(int index=0;index<MAX_KEY;index++){
#<m2Xo?d] if(hCallWnd[index]==NULL)
h@ ZC{B continue;
4Y1^ U{A+ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Z>Rshtg {
U*sQ5uq SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
t4:/qy bProcessed=TRUE;
>Jn` RsuV }
,H/O"%OJ }
[]
"bn9
+ }
40].:9VG if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
4,X CbcC for(int index=0;index<MAX_KEY;index++){
<GQ=PrT|/ if(hCallWnd[index]==NULL)
zIS ,N ' continue;
4s_5>r4 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Q7v1xBM SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
@RuMo"js //lParam的意义可看MSDN中WM_KEYDOWN部分
1?8M31 }
&1yErGXC }
-:45Q{u/ }
?^7X2 u$nm return CallNextHookEx( hHook, nCode, wParam, lParam );
Zn)o@'{}{ }
\21Gg%W5AE Tl-%;X<X 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:
0ZI}eZA j ZDI?"dt{ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
,g"JgX BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
OR+py.vK ;KmrBNF 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:
a;~< iB;3" 152s<lu1Z LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
e!w2_6?3 {
+`B^D if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
g@/}SJh/> {
?GLCd7TP //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
6iEg]FI SaveBmp();
{o*$|4q4 return FALSE;
3X ',L*f }
xkSVD6Km …… //其它处理及默认处理
ubVZEsoW? }
i$6a0'@U hV)
`e"r\s /f+BeQ3#/ 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
8+Gwv
SDU P (Y\l 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
b^}U^2S% Vl<7> 二、编程步骤
Y;g\ @j wHx_lsY; 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
n8T'}d+mm \ZE=WvnhZ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
Q~' \oWz Pl`Nniy 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
H}CmSo8& %CgV:.,K 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
hK{<&T 4HGS 5、 添加代码,编译运行程序。
n3-VqYUP 4)'U!jSb 三、程序代码
,]n~j-X AKk& ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
7i#/eRui #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
H ="I=} #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
j}(m$j' #if _MSC_VER > 1000
,LmP >Q. #pragma once
91q #endif // _MSC_VER > 1000
JB.U& #ifndef __AFXWIN_H__
[9MbNJt 8~ #error include 'stdafx.h' before including this file for PCH
F=#V/ #ia #endif
fWi/mK3c #include "resource.h" // main symbols
)t\aB_ = class CHookApp : public CWinApp
###>0(n {
$P%cdJ T0 public:
5nsoWqnE8 CHookApp();
0?gHRdU" // Overrides
BIe:7cR% // ClassWizard generated virtual function overrides
n"Bc2}{ //{{AFX_VIRTUAL(CHookApp)
/Bh*MH public:
[8[<4~{ virtual BOOL InitInstance();
{0-rnSjC virtual int ExitInstance();
K1]3zLnS //}}AFX_VIRTUAL
x7G*xHJ //{{AFX_MSG(CHookApp)
JAXD\StC // NOTE - the ClassWizard will add and remove member functions here.
D&~%w! // DO NOT EDIT what you see in these blocks of generated code !
%NC/zqPH~ //}}AFX_MSG
b`=g#B| DECLARE_MESSAGE_MAP()
G|8>Q3D };
&`tAQN*Z LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
1)zXv BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
?.H]Y&XF BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
f:J-X~T_f BOOL InitHotkey();
~<s =yjTu+ BOOL UnInit();
BpYxH#4 #endif
"dvo@n| K4YD}[ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
(+/d*4 #include "stdafx.h"
ylQj2B,CB #include "hook.h"
8Gnf_lkI #include <windowsx.h>
lmD[Cn #ifdef _DEBUG
c$tX3ug6I #define new DEBUG_NEW
X ,^([$ #undef THIS_FILE
JEMc _ngR! static char THIS_FILE[] = __FILE__;
FOMJRq #endif
Pw thYy #define MAX_KEY 100
cGdYfi #define CTRLBIT 0x04
e"NP]_vh, #define ALTBIT 0x02
R*6B@<p,i #define SHIFTBIT 0x01
SPt/$uYJ #pragma data_seg("shareddata")
dl6U]v= HHOOK hHook =NULL;
p:W] UINT nHookCount =0;
Qr4 D static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
ctjQBWE static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
_*Z3,*~"X static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
5r~jo7 static int KeyCount =0;
g=@d!]Z~[ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
n_9Ex&?e #pragma data_seg()
1
ptyiy HINSTANCE hins;
gkA_<,38 void VerifyWindow();
#9!7-!4pW BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
5Pn.c! //{{AFX_MSG_MAP(CHookApp)
,$>l[G;Bm // NOTE - the ClassWizard will add and remove mapping macros here.
Yv@n$W`: // DO NOT EDIT what you see in these blocks of generated code!
HG?+b //}}AFX_MSG_MAP
=W:=}ODD END_MESSAGE_MAP()
/WE\0bf (tg9"C CHookApp::CHookApp()
+qC[X~\ {
L~Peerby // TODO: add construction code here,
2Ki_d // Place all significant initialization in InitInstance
]7Sf) }
}l[e@6r F ~~-VScG& CHookApp theApp;
#fns3=/H LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
/o 'lGvw {
HdB>CVuh BOOL bProcessed=FALSE;
Q!V:=d if(HC_ACTION==nCode)
'o#oRK{# {
-mG`* 0 if((lParam&0xc0000000)==0xc0000000){// Key up
/[\g8U{5B} switch(wParam)
PE4
L7 {
Q+9:]Bt case VK_MENU:
%
_E?3 MaskBits&=~ALTBIT;
UgS`{&b36 break;
pa+'0Y]71 case VK_CONTROL:
d9;&Y?fp MaskBits&=~CTRLBIT;
72Y6gcg break;
(b<0=U case VK_SHIFT:
O=RS</01! MaskBits&=~SHIFTBIT;
#YE?&5t break;
nf 8V:y4 default: //judge the key and send message
Jl`^`Yv break;
$$1t4=Pz }
"N6HX* for(int index=0;index<MAX_KEY;index++){
Hf]:mhH if(hCallWnd[index]==NULL)
7N[".V]c continue;
P{6$".kIY if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
%N<5ST>( {
iiIns.V SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
HC6U_d1-6 bProcessed=TRUE;
;98b SR/ }
@`4T6eL5 }
+yWD>PY( }
xBTx`+%WS else if((lParam&0xc000ffff)==1){ //Key down
<7\j\` switch(wParam)
018SFle {
nZ(]WPIN" case VK_MENU:
:.e'?a MaskBits|=ALTBIT;
?IHt T3'Rt break;
=?6c&Z case VK_CONTROL:
.b3h?R*& MaskBits|=CTRLBIT;
AF{uFna break;
y%i9 b&gDd case VK_SHIFT:
B\RAX# MaskBits|=SHIFTBIT;
)tI^2p{ break;
))|d~m default: //judge the key and send message
{kk%_q break;
{S{ %KkAV }
\DQu!l@1U for(int index=0;index<MAX_KEY;index++)
z!3=.D {
?K[Y"*y2 if(hCallWnd[index]==NULL)
A
r]*?:4y[ continue;
}S uj=oFp if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
;m7G8)I {
6^LXctW. SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
HXKM<E{j bProcessed=TRUE;
'/u|32 }
.8|wc }
)hrsA&1w
}
Z|n|gxe if(!bProcessed){
>k\pSV[ for(int index=0;index<MAX_KEY;index++){
0Gs\x if(hCallWnd[index]==NULL)
c36p+6rJk= continue;
MT~^wI0a if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
'M~`IN` SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
)&1v[]%S }
W94:% }
A,_O=hA2I }
`#ruZM066 return CallNextHookEx( hHook, nCode, wParam, lParam );
"++\6H< }
bHG<B Q^f{H. BOOL InitHotkey()
RlL]p`g {
JW[6
^Rw if(hHook!=NULL){
}"T Q\v$ nHookCount++;
Xb%Q%"?~ return TRUE;
dB_0B. }
5K1cPU~o_b else
wmGcXBHt$ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
W\zZ&*8$ if(hHook!=NULL)
H7tviSTd nHookCount++;
1GK.:s6.f return (hHook!=NULL);
Mm@G{J\\ }
[o<hQ`& BOOL UnInit()
4tCM2it% {
v`,!wS
if(nHookCount>1){
_dm0*T ? nHookCount--;
0fewMS* return TRUE;
s9+):,dKP }
$b|LZE\bU. BOOL unhooked = UnhookWindowsHookEx(hHook);
.1[.f}g$J if(unhooked==TRUE){
9PKXQp nHookCount=0;
F~6]II hHook=NULL;
U/enq,-F^ }
.+1I>L return unhooked;
JhFn"(O }
Ge`7`D>L l}/_(* BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
'UsR/h5T {
1k6asz^T BOOL bAdded=FALSE;
!s-A`}
s+ for(int index=0;index<MAX_KEY;index++){
o08g]a if(hCallWnd[index]==0){
;F258/J hCallWnd[index]=hWnd;
C<J*C0vQO HotKey[index]=cKey;
:o!Kz`J HotKeyMask[index]=cMask;
H*N <7# bAdded=TRUE;
#4m5I=" KeyCount++;
0E26J@jcZ7 break;
3`reXms*{ }
z]N#.utQ }
O6Py return bAdded;
[`GSc6j }
}oZ8esZU2 :o^ioX.J BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
hOB<6Tm[ {
)L9eLxI BOOL bRemoved=FALSE;
x >a h, for(int index=0;index<MAX_KEY;index++){
f)_<Ih\/7_ if(hCallWnd[index]==hWnd){
@]n8*n if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
l!:bNMd hCallWnd[index]=NULL;
?Vg~7Eu0 HotKey[index]=0;
B7uK:J:c*H HotKeyMask[index]=0;
PFp!T [) bRemoved=TRUE;
legWY)4D; KeyCount--;
%q|*}l break;
AVjRhe }
FBl,Mky }
/)TeG]Xg }
lx2#C9L_ return bRemoved;
4C?{p%3c }
0\!Bh^++1 9!=4}:+ void VerifyWindow()
K{_~W yRF {
OF<:BaRs/ for(int i=0;i<MAX_KEY;i++){
vx?KenO} if(hCallWnd
!=NULL){ |I1,9ex
if(!IsWindow(hCallWnd)){ 2T*kmDp
hCallWnd=NULL; 4Vi*Qa_,y
HotKey=0; fwt+$`n
HotKeyMask=0; Y&b Yaq
KeyCount--; &]a(5
} je$H}D
} H%m^8yW1
} UZt3Ua&J
} TkTGYh
KLM6#6`
BOOL CHookApp::InitInstance() "oxUKT
{ i +@avoW
AFX_MANAGE_STATE(AfxGetStaticModuleState()); I`B ZZ-
hins=AfxGetInstanceHandle(); xKL(:ePS
InitHotkey(); G$YF0Nc
return CWinApp::InitInstance(); DA=LR
} br88b`L
< k(n%
int CHookApp::ExitInstance() 2Ax(q&`9
{ #vK99S2
VerifyWindow(); "T /$K
UnInit(); Z]LP18m9kl
return CWinApp::ExitInstance(); t_I-6`8o]
} MA tF,
&56\@t^
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file )]Zdaw)X
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_)
XU"G
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ zfUj%N
#if _MSC_VER > 1000 Jyd[Sc)
#pragma once -"Kjn`8
#endif // _MSC_VER > 1000 HHyN\
;(E]mbV'=
class CCaptureDlg : public CDialog W"/,<xHuh
{ tWZ8(E$
// Construction CiU^U|~ 'L
public: %QDAog
BOOL bTray; D@w&[IF
BOOL bRegistered; Tw/7P~*
BOOL RegisterHotkey(); I&8!V)r)
UCHAR cKey; cPL6(&7
UCHAR cMask; \o,et9zDJ3
void DeleteIcon(); )q!dMZ(
void AddIcon(); \SmYxdU'>
UINT nCount; G?s;L NR
void SaveBmp(); Xhyc2DKa_
CCaptureDlg(CWnd* pParent = NULL); // standard constructor /$qB&OWJn
// Dialog Data _B4N2t$
//{{AFX_DATA(CCaptureDlg) Ki:98a$
enum { IDD = IDD_CAPTURE_DIALOG }; 4.%/u@rAi
CComboBox m_Key; S2I{?y&K
BOOL m_bControl; LD|T1.
BOOL m_bAlt; kU)E-h
BOOL m_bShift; }i;!p
Ue$
CString m_Path; ,mp^t2
CString m_Number; ;cv\v(0
//}}AFX_DATA X=Y>9
// ClassWizard generated virtual function overrides YTe8C9eO
//{{AFX_VIRTUAL(CCaptureDlg) c@O7,y:`I
public: wuqB['3
virtual BOOL PreTranslateMessage(MSG* pMsg); ]x_14$rk
protected: z\J#d 1e
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support 7BgA+Fz
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); yrMakT =
//}}AFX_VIRTUAL \$8p8MP<&D
// Implementation y9GaxW*&