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:
um2a#6uo
.biq)Le 一、实现方法
9K+>;` 2\xw2VQ@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:
/v{+V/'+ qN!oN* #pragma data_seg("shareddata")
9zp!lw~;+ HHOOK hHook =NULL; //钩子句柄
&,nv+>D UINT nHookCount =0; //挂接的程序数目
1QoW/X'>. static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
\[MAa:/ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
I
]m static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
y'R} static int KeyCount =0;
fUT[tkb/! static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
?UXFz' #pragma data_seg()
":!$Jnj, :#rP$LSYC 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。
-&Rv=q> {;yO3];Hqw 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:
*;<fh,wOk KWJVc
` BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
WTSh#L cKey,UCHAR cMask)
yaUtDC.| {
\v2!5z8| BOOL bAdded=FALSE;
E>~R P^?Uz for(int index=0;index<MAX_KEY;index++){
n$iX6Cd if(hCallWnd[index]==0){
=?i?-6M hCallWnd[index]=hWnd;
&W<7!U:2m HotKey[index]=cKey;
#ArrQeO 5_ HotKeyMask[index]=cMask;
6h:QSVfx bAdded=TRUE;
n
Bu!2c KeyCount++;
?@64gdlwq break;
OH`a3E{e }
\6b~$\~B }
u$nzpw0=H return bAdded;
6!<I'M'[e }
"Y&I#&$b\ //删除热键
[&lK.?V) BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
il0K ^i {
O. * 0;5 BOOL bRemoved=FALSE;
(v]%kXy/G for(int index=0;index<MAX_KEY;index++){
3?93Pj3oPt if(hCallWnd[index]==hWnd){
3[m~-8 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
R"nB4R0Uh hCallWnd[index]=NULL;
g4?2'G5m? HotKey[index]=0;
Oa[ HotKeyMask[index]=0;
%|-N{> wKy bRemoved=TRUE;
|XyX%5p* KeyCount--;
QPlU+5Cx break;
i<QDV
W9 }
"[)G{VzT }
egoR])2> }
"{0G,tdA return bRemoved;
i
;FKnK }
THrLX;I ,KY;NbL-Jp .LzA'q1+z DLL中的钩子函数如下:
N ,~O+ ~D52b1f LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
P\U<,f {
qt8Y3:=8l BOOL bProcessed=FALSE;
*!5CL' if(HC_ACTION==nCode)
MAa9JA8kw) {
u~uzKG if((lParam&0xc0000000)==0xc0000000){// 有键松开
vhe Y
F@ switch(wParam)
v?8WQNy {
6N/(cUXJ case VK_MENU:
ghQ B MaskBits&=~ALTBIT;
?t/qaUXN break;
iOfm:DTPr case VK_CONTROL:
l}nV WuD MaskBits&=~CTRLBIT;
(i&+= +"wn break;
"x,lL case VK_SHIFT:
8ro`lX*F@2 MaskBits&=~SHIFTBIT;
=z1Lim- break;
~
#jQFyOh default: //judge the key and send message
H%_^Gy8f break;
q"d9C)Md }
8hGyh# for(int index=0;index<MAX_KEY;index++){
y_X6{}Ke if(hCallWnd[index]==NULL)
oz!)x\m*H continue;
`z!AjAT-G if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
z'L0YqXG/ {
~Ntk-p SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
T3w%y`K bProcessed=TRUE;
*C*J1JYp+ }
DB}Uzw| }
6-U_TV }
9q;O`& else if((lParam&0xc000ffff)==1){ //有键按下
!BQt+4G7 switch(wParam)
$QJ3~mG2 {
*i"9D: case VK_MENU:
xm m,-u MaskBits|=ALTBIT;
o/AG9|()4 break;
~j!n`#.\ case VK_CONTROL:
i"Jy>' MaskBits|=CTRLBIT;
(4H\ho8+mp break;
SioeIXU case VK_SHIFT:
J= A)]YE MaskBits|=SHIFTBIT;
[S6u:;7 break;
fUw:jExz default: //judge the key and send message
"Q: Gd6?h; break;
x^s,<G }
f;E#CjlTL for(int index=0;index<MAX_KEY;index++){
+d,
~h_7! if(hCallWnd[index]==NULL)
ieyK$q continue;
VDxm|7 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
k1Y\g'1
{
M;A_'h?Z SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
[RF,0>^b bProcessed=TRUE;
K^WDA]) }
%.bDK} }
1_Yx]%g< }
C4m+Ta% if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
r8:r}Qj2w[ for(int index=0;index<MAX_KEY;index++){
/?.?1-HM if(hCallWnd[index]==NULL)
p6JTNxD continue;
g->*@%?<w> if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Nl\`xl6y] SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
=,XCjiBeC //lParam的意义可看MSDN中WM_KEYDOWN部分
@pH2"k|
@ }
#`Su3~T=S }
eWH0zswG }
~WA@YjQ] return CallNextHookEx( hHook, nCode, wParam, lParam );
4Kj.o }
c=sV"r? *Y> w0k 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:
QK_5gD`$a, VEps|d3,, BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
|\(uO|)ju BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
a`wjZ"}'[ 3kxo1eb
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:
Sca"LaW1 7Kw'Y8 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
4[lFurH {
!2t7s96 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
CCTU-Xz/ {
+\=g&G, //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
1l-5H7^w2? SaveBmp();
-Y_,
.'ex return FALSE;
S,5ok0R }
t$BjJ -G …… //其它处理及默认处理
[8QK @5[ }
;Gr
{ 1I%u)[;> .fWy\r0 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。
f:-)S8OJ sH6;__e 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。
(.-4Jn -XYvjW,| 二、编程步骤
D07M!U z:Am1B 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";
~"+"6zg 1EU4/6!C 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
_=g&^_ #t 9evr!=": 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;
TgkVd]4% 6]7csOE 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;
5FZw
(E 12 p`ZD= 5、 添加代码,编译运行程序。
9E7 G%- t}+/GSwT 三、程序代码
1Vpti4OmU rC8p!e.yL ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
GxdAOiq; #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
&nEL}GM)E #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
|k.'w<6mb9 #if _MSC_VER > 1000
]p! { #pragma once
xmg3,bO #endif // _MSC_VER > 1000
eiK_JPF A- #ifndef __AFXWIN_H__
*PF<J/Pr #error include 'stdafx.h' before including this file for PCH
^hLr9k #endif
_LJF:E5L #include "resource.h" // main symbols
2yA)SGri class CHookApp : public CWinApp
W
)FxN, {
~qinCIj public:
9c^ ,v_W@ CHookApp();
#/>TuJc // Overrides
um,f!ho-U // ClassWizard generated virtual function overrides
j_JY[sex //{{AFX_VIRTUAL(CHookApp)
z0[@O)Sj public:
ggDT5hb virtual BOOL InitInstance();
bRvGetX virtual int ExitInstance();
=:rg1wo"c //}}AFX_VIRTUAL
$tZ
{>!N //{{AFX_MSG(CHookApp)
5`^@k< // NOTE - the ClassWizard will add and remove member functions here.
SAP/jD$5]> // DO NOT EDIT what you see in these blocks of generated code !
N{%7OG //}}AFX_MSG
8'PZA,CW DECLARE_MESSAGE_MAP()
zYzV!s2^ };
6n]+(= LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
3U<m\A1 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
ceUe*}\cr BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
sS-dHa BOOL InitHotkey();
9q"kM BOOL UnInit();
nCY kUDnZ #endif
Ty g>Xv <YvXyIs //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
01A{\O1$j #include "stdafx.h"
`
-_! %m/ #include "hook.h"
8w5}9}xF #include <windowsx.h>
SwOW%o #ifdef _DEBUG
x;~:p;]J2F #define new DEBUG_NEW
UWT%0t_T #undef THIS_FILE
</ [.1&S+\ static char THIS_FILE[] = __FILE__;
S= 4o@3%$ #endif
9xR5Jm>k #define MAX_KEY 100
ovKM;cRs/ #define CTRLBIT 0x04
ABCm2$< #define ALTBIT 0x02
Yg&(kmm #define SHIFTBIT 0x01
gG?@_ie #pragma data_seg("shareddata")
7P1Pk?pxy HHOOK hHook =NULL;
4)gG_k UINT nHookCount =0;
sh
:$J[ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
M=iTwK static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
uSfHlN4l static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
i<Z% static int KeyCount =0;
=UKxf static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
3RaduN] #pragma data_seg()
G^.N$wcv HINSTANCE hins;
E0ED[d, void VerifyWindow();
)ce 6~ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
R1zt6oY //{{AFX_MSG_MAP(CHookApp)
5m1J&TZ0 // NOTE - the ClassWizard will add and remove mapping macros here.
+p%3pnj:K // DO NOT EDIT what you see in these blocks of generated code!
.~i|kc]Ue //}}AFX_MSG_MAP
Go%Z^pF3CO END_MESSAGE_MAP()
VM$n|[C~ FCt<h/ CHookApp::CHookApp()
3L&: {
7${<u 0((! // TODO: add construction code here,
sT?{ // Place all significant initialization in InitInstance
Uj5-x%~ }
gWr7^u&q@| Ksx-Y" CHookApp theApp;
!+SL=xy!{ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
%5e| {
p]kEH\
sh BOOL bProcessed=FALSE;
h%EeU
3 if(HC_ACTION==nCode)
$9G&
wH>{ {
.`IhxE~mN if((lParam&0xc0000000)==0xc0000000){// Key up
E+\?ptw switch(wParam)
z"4 q%DC {
72;'8 case VK_MENU:
MG=E
6: MaskBits&=~ALTBIT;
BdD]HXB|_ break;
t=Oq<r case VK_CONTROL:
p)SW(pS MaskBits&=~CTRLBIT;
NO~G4PUM0C break;
lrE"phYk case VK_SHIFT:
{]\7
M|9\
MaskBits&=~SHIFTBIT;
9 :2Bt <q break;
{8.Zb NEJ
default: //judge the key and send message
M8-8T break;
|"}rdOV) }
dqB,i9-- for(int index=0;index<MAX_KEY;index++){
3S3 a|_+% if(hCallWnd[index]==NULL)
X(tx8~z continue;
H8YwMhE7 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Un]wP` {
$q\"d?n SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
JL,Y9G*]s bProcessed=TRUE;
E+Bc>xl@m }
`dm*vd }
vhF9|('G }
J=-z~\f56 else if((lParam&0xc000ffff)==1){ //Key down
L!:NL#M switch(wParam)
qIJc\,' {
eQi^d/yi case VK_MENU:
!\#Wq{p>W* MaskBits|=ALTBIT;
DCp8rvUI break;
P6_Hz!vE case VK_CONTROL:
e[iv"|+
MaskBits|=CTRLBIT;
y^H5iB[SPL break;
;?{^LiD+F case VK_SHIFT:
+2{ f>KZ MaskBits|=SHIFTBIT;
rfonM~3?' break;
f:M^q ; default: //judge the key and send message
,
>WH)+a break;
LZ)g&A(j? }
d*tWFr|J- for(int index=0;index<MAX_KEY;index++)
t0f7dU3e;L {
n1;a~0P if(hCallWnd[index]==NULL)
T8m]f< continue;
&vmk!wAs if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
:? )!yI {
Un8' P8C SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
(EcP'F*;;y bProcessed=TRUE;
pT=^o }
[.>=>KJ_ }
79 4UY }
K1X-<5]{ if(!bProcessed){
Y-})/zFc for(int index=0;index<MAX_KEY;index++){
X QLP|v;" if(hCallWnd[index]==NULL)
U LS>v continue;
B!mHO*g if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
#)}BY"C% SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
{*;8`+R& }
K\ Wzh; }
g#i~^4-1 }
x"Ll/E)\v] return CallNextHookEx( hHook, nCode, wParam, lParam );
Pt85q?- > }
_xAru9=n^ kL zjK]4 * BOOL InitHotkey()
xp1/@Pw? {
KGDN)@D if(hHook!=NULL){
(LsVd2AbR nHookCount++;
<N<0 ?GQ return TRUE;
W!HjO; }
(ORbhjl else
.=YV hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
g5#LoGc if(hHook!=NULL)
+FNGRL nHookCount++;
K3vZ42n return (hHook!=NULL);
[GbrKq( }
/
xv5we~ BOOL UnInit()
,JI] Eij^ {
#8XmOJ"W3k if(nHookCount>1){
1$DcE> nHookCount--;
(P?|Bk[ return TRUE;
\X\< +KU }
a)W|gx6Y BOOL unhooked = UnhookWindowsHookEx(hHook);
t8Pf~v if(unhooked==TRUE){
~hq\XQX nHookCount=0;
*
4J!@w hHook=NULL;
f-#:3k*7S }
PI L)(%X return unhooked;
W'9{2h6u( }
TAh'u|{u2 H,c1&hb/w BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
)-X8RRw' {
_886>^b@ BOOL bAdded=FALSE;
RCfeIHL for(int index=0;index<MAX_KEY;index++){
$MvKwQ/ if(hCallWnd[index]==0){
D0 k ,8| hCallWnd[index]=hWnd;
kj2qX9Ms HotKey[index]=cKey;
R<1%Gdz HotKeyMask[index]=cMask;
waz5+l28 bAdded=TRUE;
d(}?
\| KeyCount++;
Ag T)J break;
Mh3.GpS }
?IeBo8 }
t$qIJt$ return bAdded;
Z[[*:9rY| }
'9]?jkl DCa[?|Y BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
i5(qJ/u {
n]vCvmt BOOL bRemoved=FALSE;
3VU4E|s> for(int index=0;index<MAX_KEY;index++){
#:=c)[G8 if(hCallWnd[index]==hWnd){
IJ+} if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
9Znc|< hCallWnd[index]=NULL;
b`%u}^B { HotKey[index]=0;
<- sr& HotKeyMask[index]=0;
Zl%)#=kO bRemoved=TRUE;
h7ZH/g$) KeyCount--;
kReZch} break;
0X99D2c }
jSBz),.XU} }
{
#B/4 }
prM)t8SE return bRemoved;
\aPH_sf, }
A%EhRAy ,y"vf^BE. void VerifyWindow()
+EA ")T<l {
F%zMhX'AG for(int i=0;i<MAX_KEY;i++){
[,st: Y if(hCallWnd
!=NULL){ 3W ]zLUn
if(!IsWindow(hCallWnd)){ 3R$R?^G
hCallWnd=NULL; Hwd^C2v
HotKey=0; VO1
HotKeyMask=0; }x$@j
KeyCount--; dR i6
} xxzUey
} f
} r
\
} vC&0UNe$
} 1r4NP
**-rPonM[
BOOL CHookApp::InitInstance() UazK0{t<f
{ RJ3uu NK7
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 8|=
c3Z
hins=AfxGetInstanceHandle(); =KO]w9+\
InitHotkey(); @fA|y
return CWinApp::InitInstance(); `B&