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:
t+,'
e|t@"MxvC 一、实现方法
<?Z [X{ :?2@qWaL 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:
`Mh3v@K: p-6Y5$Y #pragma data_seg("shareddata")
YKUb'D:t] HHOOK hHook =NULL; //钩子句柄
va>u1S<lO UINT nHookCount =0; //挂接的程序数目
B=>VP-: static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
o4%H/|Oq. static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
/e2CB "c static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
^n5rUwS> static int KeyCount =0;
nE2w? static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
wNk 0F7Ck #pragma data_seg()
9_h
V1: _V.MmA 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
IzuYkl} 0:CIM DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
a7]wPXKq prWK U BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
Q.]$t
2J cKey,UCHAR cMask)
s9Tp(Yr,k {
'^npZa'%sW BOOL bAdded=FALSE;
U9*uXD1\ for(int index=0;index<MAX_KEY;index++){
Z}8khNCYr if(hCallWnd[index]==0){
y:m
;_U,%c hCallWnd[index]=hWnd;
z(8:7 G HotKey[index]=cKey;
\6{w#HsP8 HotKeyMask[index]=cMask;
(R9{wGV [ bAdded=TRUE;
`/"rs@ KeyCount++;
17
k9h?s* break;
Sj[iKCEKtv }
=T?:b8yV }
R2e":`0I return bAdded;
*NC9S,eSP }
/.1yxb#Z?, //删除热键
>!D^F]CH BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
iF_#cmSy$ {
3tt3:`g BOOL bRemoved=FALSE;
HGwSsoS for(int index=0;index<MAX_KEY;index++){
Q{:5gh if(hCallWnd[index]==hWnd){
c*k%r2' if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
;v*J:Mn/= hCallWnd[index]=NULL;
(}#8$ ) HotKey[index]=0;
)F$<-0pT HotKeyMask[index]=0;
#[uDVCM bRemoved=TRUE;
]gw[
~ KeyCount--;
InAx;2'A: break;
9 W7 ljUg }
Wq+a5[3" }
wm'a)B? }
t1Zcr#b> return bRemoved;
~YH'&L.O }
+sW;p?K7eO mw\
z' :j)v=qul DLL中的钩子函数如下:
1@i|[dq `<"@&N^d LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
|#Gug(' {
F=B[%4q`% BOOL bProcessed=FALSE;
pGsk[. if(HC_ACTION==nCode)
k6}M7&nY {
Fad.!%[ if((lParam&0xc0000000)==0xc0000000){// 有键松开
mRNA ,* switch(wParam)
js$L<^7 {
_, ki/7{ case VK_MENU:
s-Z< MaskBits&=~ALTBIT;
j6JK4{ break;
'#oNOU case VK_CONTROL:
Rs +), MaskBits&=~CTRLBIT;
F%]ZyO9 break;
<TDp8t9bU case VK_SHIFT:
-5 Q
gJ MaskBits&=~SHIFTBIT;
B&M-em= break;
Jn#05Z default: //judge the key and send message
Z)7|m break;
pnpx`u; }
4#D<#!]^ for(int index=0;index<MAX_KEY;index++){
7~ I*u6zY if(hCallWnd[index]==NULL)
t/k MV6 continue;
w<P$)~6 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
w Avnj {
e!B>M{ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
^E#i5d+'N bProcessed=TRUE;
.XVW2ISv }
it#,5#Y: }
\ ";^nk* }
n9w(Z=D\ else if((lParam&0xc000ffff)==1){ //有键按下
na4^>:r~ switch(wParam)
u^ 3,~:E {
JQ~[$OGH case VK_MENU:
6z'3e\x MaskBits|=ALTBIT;
SZ&I4- break;
7:S4 Ur case VK_CONTROL:
)ZQ>h{}D MaskBits|=CTRLBIT;
gic!yhsS_ break;
]_EJ "'x case VK_SHIFT:
\,ko'48@ MaskBits|=SHIFTBIT;
B*3<(eI break;
,pHQv(K/ default: //judge the key and send message
%@~;PS3kd break;
TpH-_ft }
L|*0
A=6 for(int index=0;index<MAX_KEY;index++){
Dga;GYx if(hCallWnd[index]==NULL)
(X3}&aLF continue;
9 \lSN5W if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
~ubcD6f {
DmA~Vj!a^y SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
N+9W2n bProcessed=TRUE;
?s-Z3{k }
5{Oq* | }
wR%F>[6.{ }
DCheG7lo{ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
s$wIL//= for(int index=0;index<MAX_KEY;index++){
}HKt{k&$ if(hCallWnd[index]==NULL)
Mjj5~by: continue;
Pl\r|gS; if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
QUO'{;, SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
>3qfo2K0 //lParam的意义可看MSDN中WM_KEYDOWN部分
csd~)a nb }
GD-cP5$ }
Zn{Y+ce7d }
{u(( y D return CallNextHookEx( hHook, nCode, wParam, lParam );
TCL XO0 }
Pea2ENe3 @km@\w 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:
Klj -dz uf/4vz, BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
2CY4nSKW BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
&~K4I M?ObK#l!_ 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:
8:sQB%BB ]/6i#fTw LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
=MjkD)l {
v 1VH&~e if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
%nV6#pr {
1$#1 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
8n"L4jb(: SaveBmp();
{bP
)Fon return FALSE;
[lz#+~rOS }
\n<9R8g5 …… //其它处理及默认处理
mFgrT }
Z'!i"Jzq|{ ?_t_rF(?6 :lBw0{fP 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
kQw%Wpuq[/ #;])/8R% 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
NyR,@n1 H{et2J<H 二、编程步骤
B(1WI_}~ cfC}"As 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
V)Sw\tS6g 7SJbrOL4Q- 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
;u*I#)7 I&wJK'GM` 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
2)MX<prH ?D_^ 8\R 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
E;rS"'D: Y.b?.)u& 5、 添加代码,编译运行程序。
ufn%sA t\XA
JU 三、程序代码
dJF3]h Y
1}Th@Vq ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
k!"6mo@rd #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
[:gp_Z& #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
,v#O{ma #if _MSC_VER > 1000
}B ?_>0 #pragma once
M)"'Q6ck= #endif // _MSC_VER > 1000
@gnLY #ifndef __AFXWIN_H__
jR2^n`D #error include 'stdafx.h' before including this file for PCH
O~#A )d6 #endif
HV=P!v6 #include "resource.h" // main symbols
1$)}EL class CHookApp : public CWinApp
>+9:31p
{
e81+as public:
ix_&os]L_ CHookApp();
"9X1T] // Overrides
8gxo{<,9 // ClassWizard generated virtual function overrides
|)y-EBZe\" //{{AFX_VIRTUAL(CHookApp)
KP)t,\@f! public:
%z6_ ,|% virtual BOOL InitInstance();
m Eg3.| virtual int ExitInstance();
`O]$FpO //}}AFX_VIRTUAL
<<PXh&wu0 //{{AFX_MSG(CHookApp)
S1o[)q
// NOTE - the ClassWizard will add and remove member functions here.
}z F,dst // DO NOT EDIT what you see in these blocks of generated code !
#Q"04'g //}}AFX_MSG
(
TJGJY DECLARE_MESSAGE_MAP()
9Cs/B*3 )b };
wv LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
1 T}jK^" BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
NpH9},1i BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
2 b80b50 BOOL InitHotkey();
%)w7t[A2D BOOL UnInit();
AAF']z<4_" #endif
B:VGa<lx5 =wMq!mBd //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Z# %s/TL #include "stdafx.h"
I23"DBR3 #include "hook.h"
~(`&hYE #include <windowsx.h>
NQcNY= #ifdef _DEBUG
aMJJ|iiU #define new DEBUG_NEW
vDIsawbHD #undef THIS_FILE
QIfP%,LT static char THIS_FILE[] = __FILE__;
88VI
_< #endif
/*(&Dmt> #define MAX_KEY 100
D67z6jep( #define CTRLBIT 0x04
jdkqJ4&i #define ALTBIT 0x02
%6la@i #define SHIFTBIT 0x01
u
s8.nL/ #pragma data_seg("shareddata")
\olY)b[ HHOOK hHook =NULL;
Z>[n~{-,p UINT nHookCount =0;
0|kH0c,T- static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
8p#V4liE static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
E., static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
BP@V:z static int KeyCount =0;
KMx
'( static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
uNca@xl' #pragma data_seg()
-^JPY)\R HINSTANCE hins;
A{Qo}F<* void VerifyWindow();
a-lF}P\ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
kDG?/j90D //{{AFX_MSG_MAP(CHookApp)
/!sGO: // NOTE - the ClassWizard will add and remove mapping macros here.
OBf$Z"i // DO NOT EDIT what you see in these blocks of generated code!
X/Ii}X/p //}}AFX_MSG_MAP
qIxe)+. END_MESSAGE_MAP()
,<$rSvMfg IP^1ca#< CHookApp::CHookApp()
5cb8=W- {
b3ys"Vyn // TODO: add construction code here,
Z>~7|vl // Place all significant initialization in InitInstance
:1;"{=Yx} }
6]mAtA`Y Z=
=c3~ CHookApp theApp;
yZ)-=H LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
p^w_-(p {
H`,t "I BOOL bProcessed=FALSE;
b#*"eZj if(HC_ACTION==nCode)
.hjN*4RY
{
K1w:JA6( if((lParam&0xc0000000)==0xc0000000){// Key up
L)
UCVm switch(wParam)
2t?Vl%< {
=7EkN% V:{ case VK_MENU:
)6%a9&~H MaskBits&=~ALTBIT;
`Ue5;<K-/ break;
j
Y(|z*| case VK_CONTROL:
]MC5 uKn MaskBits&=~CTRLBIT;
[#fz[U break;
k\RS L case VK_SHIFT:
CSH*^nk':O MaskBits&=~SHIFTBIT;
!b$]D?=} break;
I|Mw*2U default: //judge the key and send message
qfRrX" break;
.*Z#;3 }
.EC~o for(int index=0;index<MAX_KEY;index++){
Y?-Ef
sK if(hCallWnd[index]==NULL)
{"*_++| continue;
>>cL"m if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
n] t3d {
LP/SblE SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
a*t>Ks'C bProcessed=TRUE;
LYiIJAZ. }
D~M*]& }
|E;+j\ }
0U !&|i\ else if((lParam&0xc000ffff)==1){ //Key down
-j@IDd7 switch(wParam)
^])s\a$ {
\odns case VK_MENU:
$~\Tl:!#? MaskBits|=ALTBIT;
7X>*B~(R break;
wh!8\9{g case VK_CONTROL:
ZZ/k7(8 MaskBits|=CTRLBIT;
Y~w1_>b break;
:
@$5M case VK_SHIFT:
$LG.rJ/* MaskBits|=SHIFTBIT;
ENI|e,'[ break;
.HRd6O; default: //judge the key and send message
iBmvy7S? break;
8"A0@fNz }
+11 oVW for(int index=0;index<MAX_KEY;index++)
KUC%Da3 {
"rVM23@
tq if(hCallWnd[index]==NULL)
"
t?44[ continue;
Hz=s)6$ey if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
*?VB/yO=0 {
~6+Um_A_L SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
c:+UC bProcessed=TRUE;
H%Z;Yt8^gt }
-:~z,F }
hLVgP&/E }
shO4>Ha if(!bProcessed){
\FF|b"E_= for(int index=0;index<MAX_KEY;index++){
",' Zr<T if(hCallWnd[index]==NULL)
V;Q@'<w continue;
Wys$#pJ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
#4!f/dWJp SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
l<'}` }
$`R=Q }
U[:=7UABU? }
+{}p(9w@ return CallNextHookEx( hHook, nCode, wParam, lParam );
[&l+V e( }
w2jB6NQX zy.v[Y1! BOOL InitHotkey()
.- []po {
1#8~@CQ :: if(hHook!=NULL){
{Z1-B60P nHookCount++;
:a:m>S<~ return TRUE;
+n)bWB% }
*}_i[6_\E else
WI.+9$1:P hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
%IDl+_j if(hHook!=NULL)
(`u+(M!^ nHookCount++;
.4[M-@4+] return (hHook!=NULL);
ylDfr){ }
@}uo:b:Q BOOL UnInit()
44KWS~ {
j&b<YPZ if(nHookCount>1){
_Y$v=!fY& nHookCount--;
!3o/c w9 return TRUE;
C4t~k }
EW3--33s BOOL unhooked = UnhookWindowsHookEx(hHook);
/Xv@g$ if(unhooked==TRUE){
y)TBg8Q nHookCount=0;
Bo1 t}#7 hHook=NULL;
,dFY] }
2vddx<& return unhooked;
dj}P|v/;z }
07:h4beT #-{ljjMQI BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
G^SDB!/@J {
NE3/>5 BOOL bAdded=FALSE;
'#~Sb8
for(int index=0;index<MAX_KEY;index++){
z6h/C{ if(hCallWnd[index]==0){
]BTISaL-R hCallWnd[index]=hWnd;
u'gsIuRJ HotKey[index]=cKey;
6UuM`eu HotKeyMask[index]=cMask;
|uX&T`7?- bAdded=TRUE;
}.=@^-JBA5 KeyCount++;
AJ6O>Euq break;
l1%*LyD }
Q8h=2YL }
PWyFys return bAdded;
+eop4 |Z }
y+izC+ A2Iqn5 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
g91xUG {
ZS@R ? BOOL bRemoved=FALSE;
vkW;qt}yO for(int index=0;index<MAX_KEY;index++){
c:s[vghH^# if(hCallWnd[index]==hWnd){
6\%#=GG if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ZW
5FL-I hCallWnd[index]=NULL;
nE:Wl HotKey[index]=0;
=,08D^ xY HotKeyMask[index]=0;
Tc|+:Usy bRemoved=TRUE;
%;J$ h^ KeyCount--;
F$9+WS`c break;
2%MS$Fto }
|Z$)t%' }
qSaCl6[Do }
E.^u:0:P return bRemoved;
k\ZU%"^J }
$]?M[sL\N7 W=2]!%3# void VerifyWindow()
;)sC{ "Jb {
5 L-6@@/ for(int i=0;i<MAX_KEY;i++){
zCu+Oi6 if(hCallWnd
!=NULL){ nQn=zbZ3
if(!IsWindow(hCallWnd)){ 9A}y^=!`
hCallWnd=NULL; Xj:\B] v]
HotKey=0; '%a:L^a?
HotKeyMask=0; (D\`:1g
KeyCount--; [&zSY