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:
P.1Z@HC
3v `@** 一、实现方法
D>Rlm,U '- #QK'p 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:
,pQ[e$u1 7m?fvKy #pragma data_seg("shareddata")
jtE'T}! d HHOOK hHook =NULL; //钩子句柄
R4$(NNC+/ UINT nHookCount =0; //挂接的程序数目
&yOl}?u static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
T\:*+W37 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
&Mt0Qa[ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
dNov= w static int KeyCount =0;
[6/8O static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
NZFUC D) #pragma data_seg()
:()K2<E OIjG`~Rx 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。
DNyt_5j&: :2:%
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#3&,G W 0V`~z-# BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
ZjrBOb cKey,UCHAR cMask)
ej=}OH4 {
:
Cli8# BOOL bAdded=FALSE;
Wc;N;K52 for(int index=0;index<MAX_KEY;index++){
roe_H> if(hCallWnd[index]==0){
&!HG.7AY hCallWnd[index]=hWnd;
6q
`Un} HotKey[index]=cKey;
h,b_8g{! HotKeyMask[index]=cMask;
aOsc_5XDR; bAdded=TRUE;
%e|UA-( KeyCount++;
{]N7kY.W break;
N$.ls48a4- }
7;]IlR6 }
M8y|Lm}o return bAdded;
1(%6X*z }
Ub4)x //删除热键
8H8Q BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
\]\ h,Y8 {
?`6Mfpvj96 BOOL bRemoved=FALSE;
&>K|F >7q for(int index=0;index<MAX_KEY;index++){
IMpL+W. if(hCallWnd[index]==hWnd){
Ke~!1S8= if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ZZfi,0R hCallWnd[index]=NULL;
N.SV*G
@ HotKey[index]=0;
#c'}_s2F[ HotKeyMask[index]=0;
aQzmobleep bRemoved=TRUE;
{BJH}vV1) KeyCount--;
#Pg?T%('` break;
h53G$Ol. }
4!
F$nmG) }
V!e*J,g }
#$!^1yO return bRemoved;
?g0dr?H }
{Hvkn{{' ]+tO ]@ Vp:RGMr DLL中的钩子函数如下:
Y$+v " 2^U?Ztth6 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Xd1+?2 {
XjxI@VXzUV BOOL bProcessed=FALSE;
gT,iH. if(HC_ACTION==nCode)
r]wy-GT {
y
S<&d#:" if((lParam&0xc0000000)==0xc0000000){// 有键松开
q 1u_r switch(wParam)
>N}+O<Fc {
<xH!
Yskc case VK_MENU:
s9fEx-!y MaskBits&=~ALTBIT;
v`:!$U*
H= break;
.cmhi3o4 case VK_CONTROL:
2(Yt`3Go( MaskBits&=~CTRLBIT;
!MmbwB' break;
A-$C6q case VK_SHIFT:
pF}E`U=Z MaskBits&=~SHIFTBIT;
N~S#(.}[ break;
5p3:8G7 default: //judge the key and send message
q>6,g>I break;
$d&7q5[ }
9,"gXsvx( for(int index=0;index<MAX_KEY;index++){
&[yYgfsp if(hCallWnd[index]==NULL)
>gn@NJ2 N continue;
!!Yf>0u#
if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Q2Uk0:M {
<YCR^?hJSi SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
i=fhK~Jd bProcessed=TRUE;
wGHVq
fm5 }
^a!oq~ZSy }
?3v-ppw% }
QPvWdjf#mM else if((lParam&0xc000ffff)==1){ //有键按下
)[yKO switch(wParam)
&iy7It {
5D3&6DCH case VK_MENU:
M[_Ptqjb MaskBits|=ALTBIT;
|47 2X&e break;
[:A">eYI case VK_CONTROL:
2%`8 MaskBits|=CTRLBIT;
qi8AK(v break;
ogya~/ case VK_SHIFT:
N2u4MI2 MaskBits|=SHIFTBIT;
$ylxl"Y break;
(;HO3Z".q$ default: //judge the key and send message
)k `+9}OO break;
V{}TG] }
hWX4 P for(int index=0;index<MAX_KEY;index++){
gDX\ p>7 if(hCallWnd[index]==NULL)
>9<rc[ continue;
XqcNFSo) if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Jr>Nc}!U {
^{E_fQJX SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Vu<mOuh bProcessed=TRUE;
OSC_-[b- }
ye| 2gH }
cn9=wm\\ }
E6- ~ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
&G3$q,`H for(int index=0;index<MAX_KEY;index++){
bF +d_t if(hCallWnd[index]==NULL)
oiz]Bd continue;
z34+1d if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Z_T~2t SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
^vOEG;TR<- //lParam的意义可看MSDN中WM_KEYDOWN部分
5?E;YyA }
ZCfd<NS? }
%r:4'$E7| }
KkR.p,/ return CallNextHookEx( hHook, nCode, wParam, lParam );
Lk-h AN{[ }
}F3}"Ik'L +]Z*_?j9{ 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:
t
Q>/1 ~6OdwGWV BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
8PG&/"K BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
FGpV
]p J]Q-#g'Z 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:
h?GE-F 2k`Q+[?{q> LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
j?!/#' {
dmMrZ1u2 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
gLbTZM4i {
)_Iu7b //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
;y>}LGG SaveBmp();
$^#q0Yx return FALSE;
uU+?:C }
!B#tJD …… //其它处理及默认处理
UXHtmi|_: }
P;ZVv{mT Vz y )jf 3tmS/tQp 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
GbC JGqOR }5QUIK~NA 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
U(<~("ocN xp"F)6 二、编程步骤
H.[(`wi!I pJQ_G`E 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
ip*UujmNyR cs]3Rp^g 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
R~#&xfMd. "
_TAo 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
5N|hsfkx pEb/ yIT" 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
T<mP.T,$! *o=( w5
5、 添加代码,编译运行程序。
M7(]NQ\TQ Lcs?2c:% 三、程序代码
cvV8; d ?,wEfwp ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
<!?ZH"F0 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
t&G #% #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
1kh()IrA #if _MSC_VER > 1000
^pocbmg #pragma once
(abtCuZ8z #endif // _MSC_VER > 1000
>i2WYT #ifndef __AFXWIN_H__
In}~bNv? #error include 'stdafx.h' before including this file for PCH
;O({|mpS\ #endif
BM02k\% #include "resource.h" // main symbols
nTz(
{q class CHookApp : public CWinApp
ZgxpHo {
HB}iT1.` public:
)79F"ltzh CHookApp();
/,ISx} // Overrides
N9O}6 // ClassWizard generated virtual function overrides
mFBuKp+0)h //{{AFX_VIRTUAL(CHookApp)
,.uI> public:
.gw6W0\F virtual BOOL InitInstance();
8oP"?ew# virtual int ExitInstance();
x\5\KGw16 //}}AFX_VIRTUAL
QV=|'
S //{{AFX_MSG(CHookApp)
TnPx.mwK\ // NOTE - the ClassWizard will add and remove member functions here.
4'L.I%#tZ // DO NOT EDIT what you see in these blocks of generated code !
<!~NG3KW[> //}}AFX_MSG
&3YXDNm DECLARE_MESSAGE_MAP()
rmhL|!
Y };
ZV~9{E8 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
d-#yN:}0 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
&t74T"(d BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
q&: t$tSS BOOL InitHotkey();
!f#[4Xw BOOL UnInit();
b*cVC^{Dy #endif
6
$+b2&V p@+D$ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
eg>]{`WQ #include "stdafx.h"
'\Uy;,tu / #include "hook.h"
L!:;H, #include <windowsx.h>
,Z[pLF #ifdef _DEBUG
}[ByN). #define new DEBUG_NEW
p+:MZP -%( #undef THIS_FILE
o@r~KFIe static char THIS_FILE[] = __FILE__;
S6c>D&Q #endif
IjRUL/\= #define MAX_KEY 100
VOrBNu #define CTRLBIT 0x04
}9Awv#+ #define ALTBIT 0x02
j$khGR! #define SHIFTBIT 0x01
f,8PPJ:, #pragma data_seg("shareddata")
c.;<+dYsm* HHOOK hHook =NULL;
ob7hNo# UINT nHookCount =0;
/SJI ~f+$ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
;)!);q+ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
4,7W*mr3( static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
~G8haN4 static int KeyCount =0;
*En4~;l static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
I<$m% #pragma data_seg()
Dmn{ppfyb HINSTANCE hins;
]{pH,vk- void VerifyWindow();
O29GPs BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
G8OnNI //{{AFX_MSG_MAP(CHookApp)
8>ODtKI* // NOTE - the ClassWizard will add and remove mapping macros here.
e1 P(-V // DO NOT EDIT what you see in these blocks of generated code!
=tqChw
//}}AFX_MSG_MAP
6Vy4]jdT5 END_MESSAGE_MAP()
R nk&:c M[Mx
g
CHookApp::CHookApp()
HmRmZ3~ {
ZgL ]ex // TODO: add construction code here,
w(R+p/RF // Place all significant initialization in InitInstance
3qrjb]E%} }
a*Ng+~5)6 p/Lk'h~ CHookApp theApp;
*!yY7 ~# LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
^a;412 {
:X#'ELo| BOOL bProcessed=FALSE;
vN`JP`IBx if(HC_ACTION==nCode)
$Q*^c"& {
+ZPn[| if((lParam&0xc0000000)==0xc0000000){// Key up
>SHW switch(wParam)
=_,j89E {
E3h-?ugO' case VK_MENU:
3 bll9Ey MaskBits&=~ALTBIT;
Ip;;@o&D break;
"$N 4S9U case VK_CONTROL:
ug9]^p/)^ MaskBits&=~CTRLBIT;
JS0957K break;
.Wvg{ S- case VK_SHIFT:
!v]~ut !p MaskBits&=~SHIFTBIT;
_Wo(;'. break;
j9$kaEf default: //judge the key and send message
8jU6N*p/ break;
{$)pkhJ }
%51HJB}C] for(int index=0;index<MAX_KEY;index++){
AR5)Uws if(hCallWnd[index]==NULL)
N##-
vV continue;
(Ei} :6,} if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
MD=!a5' {
cW\Y1=Gv| SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
&%` 0&y bProcessed=TRUE;
m7m)BX%O }
p"=8{LrO }
.oxeo0@~ }
z#{%[X2 else if((lParam&0xc000ffff)==1){ //Key down
K{]\}7+
switch(wParam)
17B` {
gYvT'72 case VK_MENU:
N1espc@j MaskBits|=ALTBIT;
NIxtT>[+3 break;
teg[l-R"7z case VK_CONTROL:
pDG>9P#mO MaskBits|=CTRLBIT;
t[b@P<F break;
{DbWk>[DkG case VK_SHIFT:
-owap-Va MaskBits|=SHIFTBIT;
n_46;lD break;
6B`,^8Lp default: //judge the key and send message
;&]oV`Ib break;
z%Ivc*x5 }
UViWejA/*u for(int index=0;index<MAX_KEY;index++)
Ln&CB!u {
#F6!x3Z if(hCallWnd[index]==NULL)
=fy'w3m continue;
d/xGo[?$ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
!eGUiE= {
Ihg1%.^V\ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
y_N h5 bProcessed=TRUE;
s f<NC>- }
Cc!LJ }
%pr}Xs(-f }
g2W ZW#a) if(!bProcessed){
7?"-NrW~ for(int index=0;index<MAX_KEY;index++){
F)hUT@ if(hCallWnd[index]==NULL)
H0Ck%5 continue;
2+qU9[kd| if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
oq9gG)F SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
bKP@-<:] }
G;v3kGn }
#EX NS r }
yU< "tg E return CallNextHookEx( hHook, nCode, wParam, lParam );
]5j1p6;(` }
uw9w{3]0f <l"rn M% BOOL InitHotkey()
fIm=^}?fwK {
W3-g]#\? if(hHook!=NULL){
}-15^2 nHookCount++;
JzuP AI return TRUE;
T,fDH!a }
U~YjTjbd else
yh"48@L'D hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
pl5Q2zq% if(hHook!=NULL)
pJPP6Be< nHookCount++;
]{PJ return (hHook!=NULL);
H5?H{ }
\:`-"Ou(* BOOL UnInit()
^U0)iz {
:ej`]yK | if(nHookCount>1){
e[*%tx H nHookCount--;
p)w{}@%r return TRUE;
/faP@Q3kR }
y`p(}X`> BOOL unhooked = UnhookWindowsHookEx(hHook);
&U0Y#11Cx if(unhooked==TRUE){
5qQ\ H} nHookCount=0;
F@Cxjz hHook=NULL;
"IKbb7x }
C#D8
E.W return unhooked;
anxwK47 }
Lt\=E8&rh OZi4S3k BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
K:8.
Dvn {
uEcK0>xp BOOL bAdded=FALSE;
"| W``&pM for(int index=0;index<MAX_KEY;index++){
i4r8146D[ if(hCallWnd[index]==0){
UA}N hCallWnd[index]=hWnd;
|t&gyj HotKey[index]=cKey;
+U*:WKdI? HotKeyMask[index]=cMask;
fD ?w!7f-1 bAdded=TRUE;
Jw)-6WJ!uO KeyCount++;
}@Ou]o break;
<CY<-H }
dEG1[QG }
TC^fyxq return bAdded;
T +~
_D }
AN
'L-
E L(w?.)E BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
=>,X)+O {
NncII5z BOOL bRemoved=FALSE;
&)#bdt[ for(int index=0;index<MAX_KEY;index++){
&&
E) if(hCallWnd[index]==hWnd){
+tvWp>T+ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
=X}s^KbI{
hCallWnd[index]=NULL;
TOXZl3s5# HotKey[index]=0;
fT HotKeyMask[index]=0;
&VfMv'%x bRemoved=TRUE;
>XK |jPK KeyCount--;
Jyo(Etp break;
njg\y }
M"|({+9eG }
nZ8f}R!f: }
ZIikDih1 return bRemoved;
A,#a?O6m }
+o^sm '$ {2MS,Ua{ void VerifyWindow()
9,G94.da {
?_+8K`B for(int i=0;i<MAX_KEY;i++){
Kuy0Ci if(hCallWnd
!=NULL){ P*.0kR1n
if(!IsWindow(hCallWnd)){ 56T{ JTo
hCallWnd=NULL; 2L|)uCb
HotKey=0; LGPPyKNx
HotKeyMask=0; LQ3J$N
KeyCount--; ^muPjM+D
} |tqYRWn0
} dPCn6
} Rg6/6/ IN
} 4+'d">+|
u:GDM
BOOL CHookApp::InitInstance() 6R+EG{`
{ wTkcR^
AFX_MANAGE_STATE(AfxGetStaticModuleState()); HA0Rv#p
hins=AfxGetInstanceHandle(); *zTEK:+_
InitHotkey(); SWPb=[WEz
return CWinApp::InitInstance(); VAet!H +]
} FCA]zR1
)2mvW1M=7;
int CHookApp::ExitInstance() -/3D0`R
{ p~NFiZ,
VerifyWindow(); _8'z"wF
UnInit(); _W^{,*p
return CWinApp::ExitInstance(); 0;avWa)Q
} pCt0[R;?
Z2^B.r#
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file `=JGlN7
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) v JPX`T|
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ x>m=n_
#if _MSC_VER > 1000 ?fmW'vs
#pragma once L+J)
#endif // _MSC_VER > 1000 cOo@UU P
kcyT#'=j
class CCaptureDlg : public CDialog bo04y)Iz
{ XYdr~/[HPy
// Construction 9 Z79
public: do&0m[x%
BOOL bTray; _5&LV2
BOOL bRegistered; CGY,I
UG
BOOL RegisterHotkey(); &