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:
?$ Dc>
p[K!.vOt+ 一、实现方法
rw$ =!iyO N}ugI`: 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:
|})v,
oB X%98k'h.y #pragma data_seg("shareddata")
?orLc,pU^ HHOOK hHook =NULL; //钩子句柄
b&*)C#7/T UINT nHookCount =0; //挂接的程序数目
;d.gVR_V static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
V2SHF static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
Q-?6o static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
:'4", static int KeyCount =0;
>qU5 (M_&L static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
}0C v J4 #pragma data_seg()
hRNnj sd _DG8V 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。
7.*Mmx~]= &u4;A[-R 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:
#=T^XHjQ #0f6X,3 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
2xBYJoF( cKey,UCHAR cMask)
U;=1v:~d {
<2e[; $ BOOL bAdded=FALSE;
eUKl( for(int index=0;index<MAX_KEY;index++){
3>6rO4, if(hCallWnd[index]==0){
FOAXm4" hCallWnd[index]=hWnd;
4$y P_3 HotKey[index]=cKey;
Yy{(XBJ~%t HotKeyMask[index]=cMask;
KRM:h`+-.- bAdded=TRUE;
S"/-)_{ KeyCount++;
Os/?iGlD*E break;
n}dLfg* }
$T6+6<
}
)SHB1U25{ return bAdded;
!mZWd' }
=u`tlN5pOT //删除热键
wg4Ol*y' BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
ZUakW3f {
oL7F^34; BOOL bRemoved=FALSE;
h2y<vO for(int index=0;index<MAX_KEY;index++){
FY)US> if(hCallWnd[index]==hWnd){
X4JSI%E if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
3$9V4v@2 hCallWnd[index]=NULL;
2v<O} HotKey[index]=0;
)S`=y-L$ HotKeyMask[index]=0;
7$v_#ZE.H bRemoved=TRUE;
bs'hA@r KeyCount--;
XM) break;
5FE& }
f#\Nz>tOhE }
A*{CT> }
h!7Lvh`o return bRemoved;
hGcu(kAC, }
9TZ 6c eVzZfB-=4} r%9=75HA DLL中的钩子函数如下:
Wjli(sT#- $|N\(}R LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
? ph>:M {
MvTp%d. BOOL bProcessed=FALSE;
x@@bC=iY$ if(HC_ACTION==nCode)
~|S}$|Mi50 {
m:c0S8#: if((lParam&0xc0000000)==0xc0000000){// 有键松开
!8Y A1 o switch(wParam)
,F n-SrB: {
VNs3. case VK_MENU:
AzVv-!Y MaskBits&=~ALTBIT;
uQ%3?bx)T break;
X6j:TF case VK_CONTROL:
/i{V21(% MaskBits&=~CTRLBIT;
^mouWw)a_ break;
TPYh<p# case VK_SHIFT:
?KWo1 MaskBits&=~SHIFTBIT;
@p@b6iLpO break;
$$XeCPs0 default: //judge the key and send message
"8Lv break;
rN,T}M=2 }
=y=MljEX for(int index=0;index<MAX_KEY;index++){
&(m01 if(hCallWnd[index]==NULL)
Hp*N% continue;
-@XOe&q if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
AwZz}J+ {
Ph)>;jU SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
7~SnY\B| bProcessed=TRUE;
o+Mc%O Z }
et/v/Hvw1 }
8~F?%!X }
>uYU_/y$2 else if((lParam&0xc000ffff)==1){ //有键按下
x.sC015Id switch(wParam)
oPVt
qQ {
r^{Bw1+ case VK_MENU:
'>HLE) l MaskBits|=ALTBIT;
ijDXh y break;
S%e)br} case VK_CONTROL:
1B@7#ozWA? MaskBits|=CTRLBIT;
?I u=os>* break;
ff]fN:}V case VK_SHIFT:
,YJn=9pTl MaskBits|=SHIFTBIT;
&A=c[pc break;
=mSu^q(l default: //judge the key and send message
'hFL`F* break;
?<T=g }
>I',%v\?@ for(int index=0;index<MAX_KEY;index++){
LQR^lD+_= if(hCallWnd[index]==NULL)
=&<d4'(Qk continue;
x<7? if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Ko)f:=Qo {
n(i/jW~0w SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
rM?
J40&. bProcessed=TRUE;
v3G$9(NE; }
UY .-Qt }
p=\Q7<Z6d, }
sY1.z5"Mm if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
4_# (y^9 for(int index=0;index<MAX_KEY;index++){
K &%8w if(hCallWnd[index]==NULL)
nTD4^' continue;
57q?:M=^ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
8c>xgFWp9 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
>s )L(DHa" //lParam的意义可看MSDN中WM_KEYDOWN部分
5hh6;) }
LnM$@ }
lBa` nG }
xZY7X&C4 return CallNextHookEx( hHook, nCode, wParam, lParam );
!,C8 }
xdVsbW)L2 [Zzztn+ 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:
SM1L^M3) qlnA7cK! BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
/,~g"y.;, BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
h
lSav?V_ @(0O9L
F 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:
2H`>Kj 3d,:,f|h LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
#hk5z;J5 {
Xq<_r^ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
FlUO3rc| {
m/;fY>}3 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
+(W7hK4ip SaveBmp();
;rNX return FALSE;
c|Z6p{)V }
oS}fr? …… //其它处理及默认处理
5"(FilM }
abCxB^5VL CNhLp# G(ZEP.h`u 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。
dk"@2%xJ2d 7-C])9 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。
=pTTXo 0{XT#H 二、编程步骤
Az-!X!O*f Z$B%V t 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
eNO[ikm uy<<m"cA; 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
fsWIz1K nrX+ ' 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
i r'C(zD= '&2-{Y [! 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
27}7
n LFr$h`_D5 5、 添加代码,编译运行程序。
&|#,Bsk"@ %$'fq*8b 三、程序代码
0F.S[!I a 7=lZZ? ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
!6z{~Z: #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
f0R+Mz8{ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
r'lANl-v #if _MSC_VER > 1000
S<-5<Pg #pragma once
9}L2$^#,NA #endif // _MSC_VER > 1000
3}fhU{-c #ifndef __AFXWIN_H__
/5Vv5d/Z4! #error include 'stdafx.h' before including this file for PCH
Z@%A(nZ_ #endif
C\OZs%]At #include "resource.h" // main symbols
Se37- class CHookApp : public CWinApp
id" l" {
?YUL~P public:
&pR 8sySu CHookApp();
TAqX
f_ // Overrides
#?,"/Btq // ClassWizard generated virtual function overrides
8EX?/33$ //{{AFX_VIRTUAL(CHookApp)
3g5r}Ug public:
%NTJih` virtual BOOL InitInstance();
cV_-Bcb virtual int ExitInstance();
K-K>'T9F} //}}AFX_VIRTUAL
F S$8F //{{AFX_MSG(CHookApp)
q~Al[`K // NOTE - the ClassWizard will add and remove member functions here.
YW&`PJ9o // DO NOT EDIT what you see in these blocks of generated code !
^SW9J^9 //}}AFX_MSG
wp5H|ctl DECLARE_MESSAGE_MAP()
+@H{H2J 4 };
YU!s;h LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
GV28&!4sS BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
@1<VvW= BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
tkkh<5{C
BOOL InitHotkey();
4tx6h<L#s BOOL UnInit();
s:(z;cj/ #endif
Plhakngj 6V}xgfB //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
TCIbPsE #include "stdafx.h"
@8+v6z #include "hook.h"
Ta/u&t4 #include <windowsx.h>
? STO#<a #ifdef _DEBUG
MZB}O"
r #define new DEBUG_NEW
p=zTY7L #undef THIS_FILE
y~\uS static char THIS_FILE[] = __FILE__;
0IP0zil #endif
s&<76kwl #define MAX_KEY 100
@*- 6DG-f #define CTRLBIT 0x04
Li$2 Gpc/ #define ALTBIT 0x02
0&b;!N!vJ #define SHIFTBIT 0x01
e&Q
w\Ze #pragma data_seg("shareddata")
>,I'S2_Zl HHOOK hHook =NULL;
#6l(2d UINT nHookCount =0;
ZLPj1L static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
c@)?V>oe static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
&%8IBT static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
#};Zgixo$ static int KeyCount =0;
};EB[n static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
065 =I+Vo #pragma data_seg()
0PsQ
1[1 HINSTANCE hins;
zA:q/i void VerifyWindow();
jUgx
;= BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
m|t\w|B2 //{{AFX_MSG_MAP(CHookApp)
N:S2X+}( // NOTE - the ClassWizard will add and remove mapping macros here.
P=\Hi.]% // DO NOT EDIT what you see in these blocks of generated code!
g W9`k,U //}}AFX_MSG_MAP
R,=8)OI2 END_MESSAGE_MAP()
rKd|s7l mZmEE2h CHookApp::CHookApp()
bNiJ"k<pN {
r4fg!]J; // TODO: add construction code here,
bD| "c // Place all significant initialization in InitInstance
Kp1 F"! }
q^n
LC6q 1oQbV`P CHookApp theApp;
{6wXDZxv LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
(TO<SY3AB {
(I'{
pF) BOOL bProcessed=FALSE;
0>]&9'cn if(HC_ACTION==nCode)
u47`&\ {
,8d&uR}x if((lParam&0xc0000000)==0xc0000000){// Key up
dK,=9DQy5 switch(wParam)
C>mFylN {
LnN:;h case VK_MENU:
B., BP MaskBits&=~ALTBIT;
3Co1bY: break;
s0/m qZ]s case VK_CONTROL:
2tCw{Om* MaskBits&=~CTRLBIT;
C8)Paop$ break;
Aayd3Ph0% case VK_SHIFT:
,dw\y/dn MaskBits&=~SHIFTBIT;
{;zHkmx break;
1uR@ZK default: //judge the key and send message
3d7A/7S break;
W1t_P&i }
F:[[@~z for(int index=0;index<MAX_KEY;index++){
D%c^j9' 1 if(hCallWnd[index]==NULL)
UQ7La 7" continue;
lN{>.q@V`r if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
\Y!=O=za] {
5MZv!N SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
UvB\kIH bProcessed=TRUE;
T4gfQ6# }
?i\V^3S n$ }
F$kiSjh9aJ }
!M9mX%UQ else if((lParam&0xc000ffff)==1){ //Key down
QZa^Cng~ switch(wParam)
aI`d {
!dcvG9JZ case VK_MENU:
d{@'&?tj MaskBits|=ALTBIT;
cfg.&P> break;
BM)a,fIgo case VK_CONTROL:
b`^?nD7 MaskBits|=CTRLBIT;
8x7TK2r break;
[;F!\B- case VK_SHIFT:
\F\7*=xk MaskBits|=SHIFTBIT;
$= 2[Q break;
.h4Z\R` default: //judge the key and send message
v)nv"o[ break;
g2'K3e?.% }
LmJ _$?o for(int index=0;index<MAX_KEY;index++)
#UI`+2w {
)=x4+)9 if(hCallWnd[index]==NULL)
589fr"Ma,6 continue;
[fb9;,x` if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
O#C0~U]dDW {
.pm%qEh SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
OT6Te& bProcessed=TRUE;
W_Y56@7e }
$vYy19z }
a>,_o(]cW }
KM"?l<x0Y if(!bProcessed){
7!m<d,]N for(int index=0;index<MAX_KEY;index++){
es.Y if(hCallWnd[index]==NULL)
>TawJ"q-6R continue;
*8yC6|wL? if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
qD=b+\F SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
M
0RA& }
B,Tv9(sv }
*-q&~ }
TeR bW return CallNextHookEx( hHook, nCode, wParam, lParam );
!bnnUCTb\ }
[z=!OFdE ZC<EPUV( BOOL InitHotkey()
Sz')1< {
R$`&g@P=" if(hHook!=NULL){
@KLX,1K nHookCount++;
Qm"~XP return TRUE;
;:J"- p }
NE)w$>0M else
M\7F1\ X hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
d/$e#8 if(hHook!=NULL)
sE|8a nHookCount++;
VsK8 :[Al return (hHook!=NULL);
Ah5o>ZtcO }
T-kHk( BOOL UnInit()
6U%d3"T {
1 <lfo^B if(nHookCount>1){
FB>P39u nHookCount--;
d.B<1"MQ return TRUE;
'}(Fj2P79 }
m6xbO BOOL unhooked = UnhookWindowsHookEx(hHook);
M\IdQY-c if(unhooked==TRUE){
';D>Z?l nHookCount=0;
l^}5PHLd hHook=NULL;
HL>l.IG? }
EUH9R8) return unhooked;
w Bm4~~_ }
p}wysVB Lk^bzW>f BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Tkp"mT
v?< {
4mX]JH`UTe BOOL bAdded=FALSE;
L5 Ai for(int index=0;index<MAX_KEY;index++){
dWwb}r(ky if(hCallWnd[index]==0){
fLSDt(c', hCallWnd[index]=hWnd;
d& v 7l HotKey[index]=cKey;
J<Ki;_=I HotKeyMask[index]=cMask;
O(.eHZ= bAdded=TRUE;
h2:TbQ KeyCount++;
qxZf!NX5 break;
np}0OX }
?hIDyM }
s`.J!^u` return bAdded;
<dBz]W }
>Kl_948
aE"dpYQ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
1}ifJ~)5S {
tO"AeZe%| BOOL bRemoved=FALSE;
4U'sBaY!K for(int index=0;index<MAX_KEY;index++){
ATmyoN2@> if(hCallWnd[index]==hWnd){
,5 3`t if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
j0Os]a hCallWnd[index]=NULL;
Olt;^>MQ HotKey[index]=0;
o`'4EVw* HotKeyMask[index]=0;
I\j- bRemoved=TRUE;
Zny9TP KeyCount--;
{%,4P_m break;
;9J6)zg !n }
61HJ% }
5,|{|/ }
H,j_2JOY= return bRemoved;
]f wW
dtz1 }
Rx.5;2m 2t{Tz}g* void VerifyWindow()
Lc-WfzT {
&rG]]IO for(int i=0;i<MAX_KEY;i++){
iP$>/ [I if(hCallWnd
!=NULL){ &Fk|"f+
if(!IsWindow(hCallWnd)){ X .K*</(g
hCallWnd=NULL; :inVwc
HotKey=0; |^F$Ta
HotKeyMask=0; j*1MnP3/8Y
KeyCount--; F)/4#[
} N1vA>(2A
} 7v.O Lp
} j``Ku@/x0
} ~Q]::
9c{ ~$zJW
BOOL CHookApp::InitInstance() o{mVXidE
{ ^b= ;
AFX_MANAGE_STATE(AfxGetStaticModuleState()); FZ8Qj8
hins=AfxGetInstanceHandle(); F6h IG G
InitHotkey(); wp:Zur5Y
return CWinApp::InitInstance(); 65mfq&"P?
} ,k9.1kjO*)
i?mUQ'H
int CHookApp::ExitInstance() OsYZa`$,
{ ps/|^8aGZ
VerifyWindow(); ,t'"3<^Jg
UnInit(); 6_tl_O7
return CWinApp::ExitInstance(); yaHkWkl
=
} qB`%+<)C
-|=)
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file -`t9@1P>
=
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) e?]HNy
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ *r!qxiY=
r
#if _MSC_VER > 1000 3z"%ht~;
#pragma once : 'jVA
#endif // _MSC_VER > 1000 9}q)AL-ga
~)ysEZl
class CCaptureDlg : public CDialog PklJU:Pu\U
{ d9T:0A`M
// Construction <