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:
+Z/Pj_.o
TLw.rEN!; 一、实现方法
0~)cAKus B`9'COw 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:
vz/.*u j<e`8ex? #pragma data_seg("shareddata")
jDOB(fE HHOOK hHook =NULL; //钩子句柄
?%#3p[ UINT nHookCount =0; //挂接的程序数目
r+d%*Dx static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
t4~Bn<= static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
w}X <]u static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
x^xlH!Sc static int KeyCount =0;
48W$, static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
0%#ZupN #pragma data_seg()
R~PD[.\u r3{Cu z 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
DTH;d-Z lN-vFna DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
M e_.X_ 1 cvoI BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
FCNYfjB% cKey,UCHAR cMask)
WeRDaG {
:a/rwZ[r BOOL bAdded=FALSE;
"|Q.{(|kO1 for(int index=0;index<MAX_KEY;index++){
1+$F= M~ if(hCallWnd[index]==0){
`ZEFH7P hCallWnd[index]=hWnd;
5&Yt=)c\ HotKey[index]=cKey;
&2u
|7U. HotKeyMask[index]=cMask;
*d=}HO/ bAdded=TRUE;
SeXgBbGAne KeyCount++;
vVo'f|fW break;
VI4mEq,V }
JR]elRR }
ho{%7\ return bAdded;
}:faHLYT }
u|}\Af //删除热键
n(Nu BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
(Z$7;OAI {
?aTH< BOOL bRemoved=FALSE;
B(Yg1jAe for(int index=0;index<MAX_KEY;index++){
q-Z<.GTq if(hCallWnd[index]==hWnd){
Wo&22,EB if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
K>.}>)0 hCallWnd[index]=NULL;
?9{^gW4| HotKey[index]=0;
vaF1e:( HotKeyMask[index]=0;
s:6K'* bRemoved=TRUE;
3HtM<su*h KeyCount--;
aB~k8]q. break;
DI8I'c-P }
l=XZBe*[g' }
Y<W9LF }
YM;ro5_KF return bRemoved;
?0X$ox }
bTeuOpp 0cB]:*W #0r^<Yn DLL中的钩子函数如下:
QmSj6pB> r&R~a9+) LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
c$[2tZ {
.CEC
g*f BOOL bProcessed=FALSE;
~`e!$= if(HC_ACTION==nCode)
?&:N|cltD {
aOg9Dqtg)f if((lParam&0xc0000000)==0xc0000000){// 有键松开
A*0X~6W switch(wParam)
+arh/pd_I {
[.|& /O case VK_MENU:
=AaF$R MaskBits&=~ALTBIT;
`/m]K~~ break;
n5~Dxk case VK_CONTROL:
_`=qc/-0 MaskBits&=~CTRLBIT;
RvA "ug.* break;
*j83E[(] case VK_SHIFT:
p\_3g!G' MaskBits&=~SHIFTBIT;
+/$&P3 break;
Yf[Cmn default: //judge the key and send message
/z^v%l break;
DmgDhNXKq }
tlO=> for(int index=0;index<MAX_KEY;index++){
nl2Lqu1 if(hCallWnd[index]==NULL)
4S>#>(n7= continue;
BIMX2.S1o if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
,O.iOT0=; {
g0jfLv SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
]2"UR_x bProcessed=TRUE;
JZnWzqFw }
yR$_$N+E }
U"Hquo }
9#7J:PfZ< else if((lParam&0xc000ffff)==1){ //有键按下
L@RIZu>ZW+ switch(wParam)
!KcWH9 {
.2.qR,"j case VK_MENU:
dC.bt|#Oz MaskBits|=ALTBIT;
e}hmS 1>H break;
HCWNo case VK_CONTROL:
$pyOn2} MaskBits|=CTRLBIT;
'Gl&Pa1g? break;
zCv"]% case VK_SHIFT:
!-<p,z MaskBits|=SHIFTBIT;
|`TgX@,#9 break;
w[tmCn+ default: //judge the key and send message
(e(:P~Ry break;
'5&s=M_ }
.7K7h^*F for(int index=0;index<MAX_KEY;index++){
.X# `k if(hCallWnd[index]==NULL)
Z}$TKO*u continue;
xpV|\2C if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
N{9v1`B {
Dp,L/1GQ8 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
UZ\u;/} bProcessed=TRUE;
:}'=`wa }
,w<S|#W~+ }
AYqX| }
:~&~y-14 if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
Xv ]W(f1 for(int index=0;index<MAX_KEY;index++){
+\d56j+D if(hCallWnd[index]==NULL)
ry`Ho8N continue;
x9UX!Z5*> if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
5d Eh7XL SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
'N (:@]4N //lParam的意义可看MSDN中WM_KEYDOWN部分
?pW`cFLDHF }
,1~"eGl! }
44ek
IV+? }
,>bh$| return CallNextHookEx( hHook, nCode, wParam, lParam );
_C%3h5 }
1gL2ia !#], hok8X 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
Yg]-wQrH dI.WK@W'o BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
B3pCy~*5 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
2V-
16Q'% v|XTr,# 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
[_R~%Yh+'E >,V9H$n LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
? &o2st {
1OGx>J6 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
u@Ih GME {
CKYc\<zR0l //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
d~9A+m3b_ SaveBmp();
^n*)7K[
return FALSE;
z`.<U{5 }
],@rS9K …… //其它处理及默认处理
vv72x] }
G,&<<2{(f; NO*u9YH? Bd!bg|uO* 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。
-o^7r@6 l.67++_ 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。
0M_ DB= qzYwt]GNS 二、编程步骤
FvaUsOy" JrJo|0Q 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";
Km qMFB62 u(z$fG:g 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
u4t7Ie*Q f}o\*|k_| 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;
Yz<3JRw :y'Ah# 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;Lkaxsn 6hno)kd{= 5、 添加代码,编译运行程序。
sQYkQ81 &y\prip 三、程序代码
D>`xzt '.6 cVXLKO ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
p2hB8zL #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
NxkGOAOE #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
e),q0%5 #if _MSC_VER > 1000
JgxtlYjl #pragma once
1vS#K=sb #endif // _MSC_VER > 1000
$iN"9N%l #ifndef __AFXWIN_H__
!]"@kl% #error include 'stdafx.h' before including this file for PCH
{0[tNth'h #endif
qLO4#CKCL6 #include "resource.h" // main symbols
@KXV%a' class CHookApp : public CWinApp
AiwOc+R {
^%d\qd` public:
'f#{{KA CHookApp();
IB(6+n,6s // Overrides
|J1$=s // ClassWizard generated virtual function overrides
^ sOQi6pL //{{AFX_VIRTUAL(CHookApp)
0.\/\V:H6 public:
C(eTR1 virtual BOOL InitInstance();
?j'7l=94A virtual int ExitInstance();
DEBB()6, //}}AFX_VIRTUAL
:,3C 0T3r //{{AFX_MSG(CHookApp)
TYy?KG>:' // NOTE - the ClassWizard will add and remove member functions here.
IQAZuN"< // DO NOT EDIT what you see in these blocks of generated code !
B~'vCuE //}}AFX_MSG
]tim,7s DECLARE_MESSAGE_MAP()
WQx?[tW(U };
Q{O+ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
$By<$ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
sZ3KT& BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
#%pI(,o= BOOL InitHotkey();
B |5]Jm] BOOL UnInit();
(j%~u&+- #endif
vt/x
,Y $|zX| //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
>,v`EIg #include "stdafx.h"
.Hescg/S #include "hook.h"
5^}\4.eXo #include <windowsx.h>
-zCH**y%1 #ifdef _DEBUG
P:hBt\5B #define new DEBUG_NEW
]>W6
bTK #undef THIS_FILE
`:ArT}F static char THIS_FILE[] = __FILE__;
hnffz95 #endif
i"1Mfz~e #define MAX_KEY 100
C>]0YO
k2 #define CTRLBIT 0x04
v>6"j1Z #define ALTBIT 0x02
^8]NxV@l #define SHIFTBIT 0x01
L,HhbTRca #pragma data_seg("shareddata")
%gInje HHOOK hHook =NULL;
rbul8(1h UINT nHookCount =0;
&r[`>B{tP static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
bpOYHc6,*` static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
kF3k7,.8& static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
gLb`pCo/ static int KeyCount =0;
"0$a)4] static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
,D5cjaX< #pragma data_seg()
<NHH^M\N HINSTANCE hins;
.14~J6 void VerifyWindow();
$ux,9H'[ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
%9
SJ
E //{{AFX_MSG_MAP(CHookApp)
\0A3]l // NOTE - the ClassWizard will add and remove mapping macros here.
o m!!Sl 3 // DO NOT EDIT what you see in these blocks of generated code!
50"pbzW //}}AFX_MSG_MAP
W= ig.- END_MESSAGE_MAP()
BfXgh'Z~ {5A2& CHookApp::CHookApp()
-TLlwxc^% {
2"COP> // TODO: add construction code here,
)i6mzzj5 // Place all significant initialization in InitInstance
f@6QvkIa }
R1PkTZP& ;[(oaK@+n CHookApp theApp;
a a<8,; LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
XYQ/^SI!: {
=-tw5],
L BOOL bProcessed=FALSE;
x-XD.qh7Hr if(HC_ACTION==nCode)
5b5x!do {
"WlZ)wyF% if((lParam&0xc0000000)==0xc0000000){// Key up
fAF1"4f switch(wParam)
f}6s
Q5 {
5sdn[Tt## case VK_MENU:
N1}c9} MaskBits&=~ALTBIT;
>d@&2F TO break;
\-L&5x"x case VK_CONTROL:
z Eq GD2" MaskBits&=~CTRLBIT;
'-QwssE break;
6e (Qwt case VK_SHIFT:
"7U4'Y:E MaskBits&=~SHIFTBIT;
xg30xC[ break;
z__EYh default: //judge the key and send message
$': E\*ICb break;
K'55O&2 }
1Vsz4P"O $ for(int index=0;index<MAX_KEY;index++){
wrviR if(hCallWnd[index]==NULL)
{SOr#{1z* continue;
8Pfb~&X^Ws if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
i1UiNJh86 {
9Q.rMs>qj SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
E{`kaWmC&~ bProcessed=TRUE;
<qtr }
4hO!\5-w: }
?:pP8/y }
*RDn0d[ else if((lParam&0xc000ffff)==1){ //Key down
tW.9yII switch(wParam)
=FlDb
5t{ {
7z/|\D_{ case VK_MENU:
5:\},n+VE MaskBits|=ALTBIT;
1!ii;s^e break;
vV6<^W:9F case VK_CONTROL:
>/g#lS 5 MaskBits|=CTRLBIT;
R(!s break;
6q*9[<8 case VK_SHIFT:
W~6EEyD% MaskBits|=SHIFTBIT;
t!* ?dr break;
cq5jP Z} default: //judge the key and send message
nx@=>E+a break;
"
f
<Z=c }
NYyh|X:m for(int index=0;index<MAX_KEY;index++)
t,QyfN {
3Q"<<pi!~ if(hCallWnd[index]==NULL)
b $'FvZbk continue;
-1
FPkp if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
83E7k]7] {
cU
R kP` SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
ATJWO1CtB bProcessed=TRUE;
.Fs7z7?Y }
2K<
8 }
d^Inb!%w }
e63uLWDT if(!bProcessed){
0QFS for(int index=0;index<MAX_KEY;index++){
N|1M1EBOu> if(hCallWnd[index]==NULL)
$()5VMb continue;
?u-|>N> if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
C+'/>=>a. SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
'r4/e-`pK }
Mx&&0#;r }
b$4"i XSQ }
B&\IGWG( return CallNextHookEx( hHook, nCode, wParam, lParam );
}
uO);k5H }
q_TRq:&. L\Aq6q@c BOOL InitHotkey()
{K <iih {
w0ht if(hHook!=NULL){
D'7SAFOM nHookCount++;
{F3xJ[ return TRUE;
2#P*, }
!HrKXy0{ else
z,Medw6[ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
o1Ph~|s*8 if(hHook!=NULL)
4~y(`\0?4 nHookCount++;
H#@^R( return (hHook!=NULL);
mX_a^_[G }
cimp/n" BOOL UnInit()
y603$Cv {
m4aB*6<lq if(nHookCount>1){
F=`AY^u0 nHookCount--;
K!:azP,bZ return TRUE;
[p{#XwN }
&Nj3h(Ll BOOL unhooked = UnhookWindowsHookEx(hHook);
(}a8"]Z if(unhooked==TRUE){
:ZTc7} nHookCount=0;
u\ #"L hHook=NULL;
0KYEb%44 }
qm./|#m> return unhooked;
WfWN(:dF }
vk+VP 1D DBPRGQ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
ad.3A{ {
{)"iiJ BOOL bAdded=FALSE;
n1JRDw"e$$ for(int index=0;index<MAX_KEY;index++){
3|WWo1 if(hCallWnd[index]==0){
d\p,2 hCallWnd[index]=hWnd;
H$@`,{M629 HotKey[index]=cKey;
}2<r, HotKeyMask[index]=cMask;
N"8_S0=pw bAdded=TRUE;
)>.&N[v KeyCount++;
:E_g"_ break;
=; ^%(%Y{m }
R<[qGt|L }
1nQWW9i return bAdded;
>_o} }
{p;zuCF1 iMI lZ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
zhpx"{_ {
hCCiD9gz BOOL bRemoved=FALSE;
86(I^= for(int index=0;index<MAX_KEY;index++){
vWRju*Z& if(hCallWnd[index]==hWnd){
dQ_!)f&w1 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ZT,B(#m hCallWnd[index]=NULL;
Q,p}:e HotKey[index]=0;
U 'R)x";= HotKeyMask[index]=0;
KHgBo}6 bRemoved=TRUE;
]Bm/eRy" KeyCount--;
IqC]! H0 break;
A3|Dz&@: }
_{r=.W+w }
lz"OC<D}( }
> ?6&c return bRemoved;
'<rZm=48 }
an|x$e7|? 0Uz\H0T1 void VerifyWindow()
;k7xMZs {
_h X]% for(int i=0;i<MAX_KEY;i++){
|55N?=8 if(hCallWnd
!=NULL){ 4T!+D
if(!IsWindow(hCallWnd)){ V#cqRE3XNi
hCallWnd=NULL; hg+X(0
HotKey=0; "kMguK}c
HotKeyMask=0; um4yF*3b9
KeyCount--; Ytz)d/3T
} gA:5M
} gyCXv0*z
} P>7PO~E.
} Angt=q
VJtRL')
BOOL CHookApp::InitInstance() tCu9
D
{ u/5)Yx+5_
AFX_MANAGE_STATE(AfxGetStaticModuleState()); nB%[\LtZ?
hins=AfxGetInstanceHandle(); AHLXmQl
InitHotkey(); ~JOC8dO
return CWinApp::InitInstance(); ~8[`(/hj
} *(nu0
<@qJsRbhK
int CHookApp::ExitInstance() tj
tN<