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:
PK@hf[YHe
FV>LD% uu 一、实现方法
hmv"|1Sa!~ 5 iUT# 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:
00 Qn1 =#||&1U$ #pragma data_seg("shareddata")
,lLkAd?q HHOOK hHook =NULL; //钩子句柄
6C>"H UINT nHookCount =0; //挂接的程序数目
h[M~cZ{ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
L$^ya%2 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
^T83E} static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
>L F
y:a static int KeyCount =0;
3>Ts7
wM static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
dHV3d'.P #pragma data_seg()
\*Roa&<! A`x_M!m 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。
*6oQW u6{=Z : 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:
c`94a SnV bLyU; BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
$gU6=vN1# cKey,UCHAR cMask)
&L[7jA'[J {
@Omgk=6 BOOL bAdded=FALSE;
/ E~)xgPM< for(int index=0;index<MAX_KEY;index++){
;Ll/rJ:* if(hCallWnd[index]==0){
] RgLTqv4x hCallWnd[index]=hWnd;
D7.|UG?G HotKey[index]=cKey;
Y;ytm
#= HotKeyMask[index]=cMask;
spIkXEK bAdded=TRUE;
V3j1M?> KeyCount++;
C'mYR3?m; break;
eYd6~T[9 }
R0dIxG% }
|F_Z return bAdded;
W<<{}'Db/# }
/XtpGk_1) //删除热键
'r;C(Gh6 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
g.![>?2$8 {
0?hJ!IT;q7 BOOL bRemoved=FALSE;
>*#clf;@p for(int index=0;index<MAX_KEY;index++){
$^|I?5xD if(hCallWnd[index]==hWnd){
DA'A-C2 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
F/c7^ hCallWnd[index]=NULL;
KUs\7Sb HotKey[index]=0;
wfr+- HotKeyMask[index]=0;
kkfwICBI bRemoved=TRUE;
Q"UWh~ KeyCount--;
6")co9 break;
'\yp}r'u }
oNV5su }
Z]-C,8MM }
hZ_0lX} return bRemoved;
iwb]mJUA }
5r1{l%? *Jd,8B/hC 1o5DQ'~n DLL中的钩子函数如下:
@R+bR<}] pyPS5vWG LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
ofeSGx {
XI6LPA0% BOOL bProcessed=FALSE;
ejY|o
Bj if(HC_ACTION==nCode)
slSQ \;CDA {
Op] L#<&T if((lParam&0xc0000000)==0xc0000000){// 有键松开
C4V#qhj switch(wParam)
^fj):n5/ {
,/V'(\>
case VK_MENU:
/rRQ*m_ MaskBits&=~ALTBIT;
Wj N0KA break;
*ml&}9 case VK_CONTROL:
p)M\q fZ MaskBits&=~CTRLBIT;
F_Q,j]0 break;
Z
Mp case VK_SHIFT:
>patv MaskBits&=~SHIFTBIT;
#L\t)W break;
0(9]m)e default: //judge the key and send message
IbRy~ break;
W!a~ #R/r- }
s
}P-4Sg for(int index=0;index<MAX_KEY;index++){
o!Vs{RRu} if(hCallWnd[index]==NULL)
xJ"CAg|B continue;
2i);2>HLG if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Ck,.4@\tK {
R#Z1+&=' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
)]2yTG[ bProcessed=TRUE;
51oZw%os= }
nU"V@_?\ }
}K=TB}yY }
1XZ|}Xz else if((lParam&0xc000ffff)==1){ //有键按下
bTzVmqGY switch(wParam)
/*GRE#7S {
<DS+"# case VK_MENU:
&k3'UN!&Ix MaskBits|=ALTBIT;
PGKXzp' break;
GVM#Xl}w9 case VK_CONTROL:
I I8nz[s MaskBits|=CTRLBIT;
+o3g]0 break;
!LJ.L?9qw case VK_SHIFT:
N 93E;B MaskBits|=SHIFTBIT;
^%d{i'9? break;
@ 7?_Yw default: //judge the key and send message
k:TfE6JZ break;
'O`3FI }
)|{{}w~` for(int index=0;index<MAX_KEY;index++){
@5y(>>C}8% if(hCallWnd[index]==NULL)
&~%@QC/ continue;
e%U*~{m+ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
' XF`&3i {
6.|~~/ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
ay_D.gxz bProcessed=TRUE;
lnDDFsA }
kpH;D=; }
$dP)8_Z2 }
pPZ/ O6 if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
$3TTHS o for(int index=0;index<MAX_KEY;index++){
NXBOo if(hCallWnd[index]==NULL)
)DmiN ^: continue;
AD\<}/3U if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Q:gn>/ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
hU
7fZl%yl //lParam的意义可看MSDN中WM_KEYDOWN部分
mx9/K+: }
nvPE
N }
f~FehN7 }
/6?plt&CA return CallNextHookEx( hHook, nCode, wParam, lParam );
'pY;]^M }
LJwM M 2&0<$> 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:
:BX{*P n^\;*1%$c@ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
pRvs;klf BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
|{)xC= EQ7n'Wqq 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
DME?kh>7 C94@YWs LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
8-a6Q|
{
Qe$>Jv5 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
n[Iu!v\/* {
yim$y,=d //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
7f%Qc %B SaveBmp();
RQCQGa^cP return FALSE;
5ek%d }
J md
? …… //其它处理及默认处理
G}#/`]o!K }
: W^\
mH &}0wzcMg fq'Xy9L 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。
g]<Z]R` _S2^;n? 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。
(kQ.tsl Oawr S{ 二、编程步骤
$xtE+EV.p mBZDl4 ' 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
k!/_/^{ p/1}>F|i 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
Zng` oFD C^" Hj 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
G0QXf <
mK 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
'}+X,Usm ^T&u!{82j 5、 添加代码,编译运行程序。
c =N]!
,MO X;6r$
三、程序代码
V2s}<uG W
B*`zCM ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
PyT}}UKj: #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
kE_@5t7O{
#define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
g<iwxF #if _MSC_VER > 1000
12d}#G<q- #pragma once
cCh5Jl@Z #endif // _MSC_VER > 1000
ah/6;,T #ifndef __AFXWIN_H__
nG^M 2)(8 #error include 'stdafx.h' before including this file for PCH
d0A\#H_& #endif
]v@ tZ} #include "resource.h" // main symbols
H@2v<e@ class CHookApp : public CWinApp
]PzTl {] {
o;VkoYV public:
8q~FUJhU CHookApp();
Vr-3M+l=O // Overrides
bmO__1 // ClassWizard generated virtual function overrides
`F2*o47|t //{{AFX_VIRTUAL(CHookApp)
A:.IBctsd public:
g;-+7ViIr virtual BOOL InitInstance();
lNaez3 virtual int ExitInstance();
qsft*& //}}AFX_VIRTUAL
CFBUQMl> //{{AFX_MSG(CHookApp)
bL'# // NOTE - the ClassWizard will add and remove member functions here.
{wpMg // DO NOT EDIT what you see in these blocks of generated code !
#U$YZ#B //}}AFX_MSG
5"}y\ DECLARE_MESSAGE_MAP()
Pv7f
_hw };
?+
-/'; LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
{V%%^Zhwy BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
8tV=fSHd BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
t*Vao BOOL InitHotkey();
#0?"J) BOOL UnInit();
1=/doo{^ #endif
wsf Hd<Z_ (RDa,& //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
-t%{"y #include "stdafx.h"
k+WO &g*| #include "hook.h"
&h7smZO5j #include <windowsx.h>
Ok}{jwJ%W; #ifdef _DEBUG
v7o?GQ75 #define new DEBUG_NEW
;z.6'EYMG #undef THIS_FILE
-YzQ2#K static char THIS_FILE[] = __FILE__;
B?$ 01?9V #endif
d`?U!?Si #define MAX_KEY 100
VQy9Y #define CTRLBIT 0x04
o%V
@D'w #define ALTBIT 0x02
ldAov\X #define SHIFTBIT 0x01
ch0oFc$ #pragma data_seg("shareddata")
MtpU~c HHOOK hHook =NULL;
}t@f|TX UINT nHookCount =0;
i"%JFj_G static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
t4f
(Y,v static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
KjFZ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
f$1Gu static int KeyCount =0;
C<[d static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
t(J![wB} #pragma data_seg()
DO7-=74= HINSTANCE hins;
XGE
2J void VerifyWindow();
:`+|'*b(A BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
6Gs{nFw //{{AFX_MSG_MAP(CHookApp)
t{/:( Nu // NOTE - the ClassWizard will add and remove mapping macros here.
V*6l6-y~Ih // DO NOT EDIT what you see in these blocks of generated code!
M|/oFV //}}AFX_MSG_MAP
"
Sc5qG END_MESSAGE_MAP()
t[]['Iosd c@RT$Q9j CHookApp::CHookApp()
e1^fUOS {
5~@?>)TBv // TODO: add construction code here,
\@Ee9C13 // Place all significant initialization in InitInstance
4=u+ozCG }
B3y?. 69t7=r CHookApp theApp;
u|(Ux~O
LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
KKLR'w,A> {
kcLj Kp BOOL bProcessed=FALSE;
Ap11b|v if(HC_ACTION==nCode)
Qo'yS"g<9) {
Of-C if((lParam&0xc0000000)==0xc0000000){// Key up
~c9>Nr9|` switch(wParam)
5JS ZLC {
4cott^K. case VK_MENU:
rei
8LW MaskBits&=~ALTBIT;
MQwIPjk8 break;
i~9?:plS case VK_CONTROL:
tS?a){^:c MaskBits&=~CTRLBIT;
*R5`.j = break;
{bT9VZ> case VK_SHIFT:
&svx@wW MaskBits&=~SHIFTBIT;
i][f#e4 break;
*3;UAfHv default: //judge the key and send message
EbCIIMbe" break;
]53O}sH> }
z(+&wa for(int index=0;index<MAX_KEY;index++){
},rav] if(hCallWnd[index]==NULL)
5gSylts8 continue;
#S%4? if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
o*X]b] {
doBNghS SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
/dLA`=r Zx bProcessed=TRUE;
L~IE,4 }
q %>7L<r }
u+m4!` }
eI^gV'UK else if((lParam&0xc000ffff)==1){ //Key down
~F;CE"3A switch(wParam)
3 -tO;GKb {
D z@1rc<B case VK_MENU:
fe|g3>/| MaskBits|=ALTBIT;
^00{Hd6 break;
(%bE~Q2P*< case VK_CONTROL:
s
_~IZ%+<. MaskBits|=CTRLBIT;
JT04vm4 break;
H8&p<= case VK_SHIFT:
5X0QxnnV MaskBits|=SHIFTBIT;
.$Y?
W< break;
X]!D;7^ default: //judge the key and send message
><=rIhG%H@ break;
l x e`u}[ }
09d9S`cS\ for(int index=0;index<MAX_KEY;index++)
ox[ .)v {
Um z05* if(hCallWnd[index]==NULL)
$eBQH continue;
V.8%|-d if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
xIL#h@dz {
qBYg[K> SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
|c0, bProcessed=TRUE;
zJY']8ah }
=WK04\H }
/;l[I=VI }
q>-R3HB if(!bProcessed){
& fu z2xv for(int index=0;index<MAX_KEY;index++){
>F[GVmC if(hCallWnd[index]==NULL)
=u=Kw R continue;
O9^T3~x[V if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
zsVcXBz SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
5/?P|T }
T@P!L }
rslvsS: }
SE)nD@: return CallNextHookEx( hHook, nCode, wParam, lParam );
;iU%Kt }
<6jFKA< s8vKKvs`9 BOOL InitHotkey()
G;s"h%Xw98 {
{x{H$ f if(hHook!=NULL){
aGK@)&h$ nHookCount++;
Fp%Ln(/m return TRUE;
I]R9HGJNlJ }
?pG/m%[ else
9I.^LZ" hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
,lm=M5b if(hHook!=NULL)
$UvPo0{ nHookCount++;
c}-(. eu return (hHook!=NULL);
g_aCHEFBv }
? ?[g}> BOOL UnInit()
8lP6-VA {
~3CVxbB^< if(nHookCount>1){
opp!0:jS* nHookCount--;
ashar&' return TRUE;
@i LIU}+ }
%
frfSGf.# BOOL unhooked = UnhookWindowsHookEx(hHook);
|PP.<ce\- if(unhooked==TRUE){
vzXag*0
nHookCount=0;
5 1dSFr<# hHook=NULL;
6BAW }
4W;S=#1 return unhooked;
~OypE4./1 }
obo&1Uv,/ RMP9y$~3pU BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
2SG$LIV 9Y {
42+#<U7T BOOL bAdded=FALSE;
)Gk`[*q ; for(int index=0;index<MAX_KEY;index++){
$yu?.b
9H# if(hCallWnd[index]==0){
%J~WC$=Qv hCallWnd[index]=hWnd;
,6,]#R
:J HotKey[index]=cKey;
nxo+?:** HotKeyMask[index]=cMask;
)L5i&UK. bAdded=TRUE;
{whvTN1#dh KeyCount++;
~*.- break;
:iUF7P1I }
#hw>tA6 }
V diJ>d[ return bAdded;
szmmu*F,U: }
](jFwxU _$s> c!t,# BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
iG<Som {
,"2TArC'z BOOL bRemoved=FALSE;
p $`92Be/ for(int index=0;index<MAX_KEY;index++){
]$b2a&r9 if(hCallWnd[index]==hWnd){
wvby?MhPY if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ZH 6\><My hCallWnd[index]=NULL;
+-$Ko fnM HotKey[index]=0;
~AB*]Us HotKeyMask[index]=0;
:iF%cy. bRemoved=TRUE;
s1j{x&OSq KeyCount--;
cr;`Tl~}s break;
CH#k(sy }
Ond'R'3 \E }
s Be7"^ }
OFU/gaO~ return bRemoved;
EHf\L }
fS&6 "sUyHt -& void VerifyWindow()
*m+BuGt| {
Wr?'$: for(int i=0;i<MAX_KEY;i++){
`Ityi} if(hCallWnd
!=NULL){ 4Y \wnwI
if(!IsWindow(hCallWnd)){ \}0-^(9zd
hCallWnd=NULL; /8'S1!zc
HotKey=0; IH*s8tPc
HotKeyMask=0; ?Bi*1V<R
KeyCount--; :mcYZPX#
} f .
}c7
} <If35Z)~
} i5}4(sV
} w8Sv*K
8hanzwoJ:
BOOL CHookApp::InitInstance() f9$xk|2g
{ b\7iY&.C|
AFX_MANAGE_STATE(AfxGetStaticModuleState()); yY).mxRN
hins=AfxGetInstanceHandle(); bC!`@/
InitHotkey(); KJn!Ap
return CWinApp::InitInstance(); s"KJiQKGM
} gY-5_Ab
rh*sbZ68>E
int CHookApp::ExitInstance() DL^o_61
{ }n:?7
VerifyWindow(); qy1F*kY
UnInit(); -_OS%ARa
return CWinApp::ExitInstance(); YIhm$A"z0"
} jEdtJEPa
DE$q+j0P
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file C G\tQbum
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) CBYX]
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ 9LnN$e
#if _MSC_VER > 1000 p/Sbt/R
#pragma once VZka}7a
#endif // _MSC_VER > 1000 URgk^nt2p
IA zZ1#/3
class CCaptureDlg : public CDialog hOv={:
{ N;oQ^B'
// Construction /hrT
public: POI.]1i
BOOL bTray; e1myH6$W
BOOL bRegistered; h5_G4J{1
BOOL RegisterHotkey(); +yob)%
UCHAR cKey; f"u*D,/sS
UCHAR cMask; eK_*2=;XRW
void DeleteIcon(); [D"t~QMr
void AddIcon(); >Hb^P)3
UINT nCount; mMx ;yZ
void SaveBmp(); N]EcEM #
CCaptureDlg(CWnd* pParent = NULL); // standard constructor ^efb
5
// Dialog Data vr^~yEr
//{{AFX_DATA(CCaptureDlg) -~[9U,
enum { IDD = IDD_CAPTURE_DIALOG }; 5vAf7\*
CComboBox m_Key; AE`We$!
BOOL m_bControl; #o/H~Iv
BOOL m_bAlt; lE8&..~l$+
BOOL m_bShift; N /$`:8"
CString m_Path; yH 9!GS#
CString m_Number; -4rDbDsr
//}}AFX_DATA 93qwH%
// ClassWizard generated virtual function overrides v0D q@Q1
//{{AFX_VIRTUAL(CCaptureDlg) jCAC
`
public: Qp"y?S
virtual BOOL PreTranslateMessage(MSG* pMsg); n~V4nj&_T
protected: N..j{FE
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support )Au6Nf
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); OdWou|Gz
//}}AFX_VIRTUAL _I`,Br:N
// Implementation q+KzIde|%
protected: P&d"V<
HICON m_hIcon; +;g{$da5
// Generated message map functions CM )Q&