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:
qL>v&Rd<
O9;dd
yx 一、实现方法
qvN"1=nJ ~y@& } 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:
Bt6xV<jD vrO%XvXW #pragma data_seg("shareddata")
]Da4.s*mW HHOOK hHook =NULL; //钩子句柄
~ a>S#S UINT nHookCount =0; //挂接的程序数目
a|z1K static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Bn_g-WrT static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
9@etg4#] static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
D8 wG!X static int KeyCount =0;
z"3H{ A static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
.)0gz!Z #pragma data_seg()
e#m1X6$.e (-'PD_| 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
rT<1S?jR `r9^:TMN DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
(ic@3:xR d1lH[r!Z BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
lux9o$ % cKey,UCHAR cMask)
rxArTpS{.# {
q!@c_o BOOL bAdded=FALSE;
DzE E:&*= for(int index=0;index<MAX_KEY;index++){
sOC|
B if(hCallWnd[index]==0){
p Mh++H]" hCallWnd[index]=hWnd;
\aB&{`iG HotKey[index]=cKey;
G
"c/a8 HotKeyMask[index]=cMask;
kw;wlFU; bAdded=TRUE;
(Otur KeyCount++;
v<`$bvv? break;
Pd,!& }
$4:~*IQ }
R1~7F{FW return bAdded;
BMF3XcH~G }
m9k2h1 //删除热键
pdy+h{]3 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
$ JuLAqq {
}R\B.2#M_@ BOOL bRemoved=FALSE;
^[*AK_o_DQ for(int index=0;index<MAX_KEY;index++){
#e*$2+`[A if(hCallWnd[index]==hWnd){
o=@ UXi if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Hj1k-Bs&'w hCallWnd[index]=NULL;
DSTx#* HotKey[index]=0;
!Am
=v=> HotKeyMask[index]=0;
5%#i79z&B bRemoved=TRUE;
-/1d& KeyCount--;
@}Pw0vC break;
s?HsUD$b }
7~L|;^( }
%va[jJ }
tPA"lBS ! return bRemoved;
HN^w'I'bp }
)y5iH){! FmR\`yY_, a3*.,%d DLL中的钩子函数如下:
_5Bu [I })q]gMj LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
OY$7`8M[ {
S[ i$e BOOL bProcessed=FALSE;
3!1&DII4 if(HC_ACTION==nCode)
xvHOY: {
;\1b{-' l if((lParam&0xc0000000)==0xc0000000){// 有键松开
5,Qy/t}K switch(wParam)
9B&
}7kk {
>&g2 IvDS case VK_MENU:
x={kjym L MaskBits&=~ALTBIT;
hgNY[, break;
Sw/J+FO2 case VK_CONTROL:
A<]&JbIt MaskBits&=~CTRLBIT;
,Z >JvTnH break;
wX@H
&)<s case VK_SHIFT:
L/c4"f|.*v MaskBits&=~SHIFTBIT;
T$f:[ye]Z break;
zv&ePq\# default: //judge the key and send message
`AB~YX%( break;
'! #On/ }
rUGZjLIGqz for(int index=0;index<MAX_KEY;index++){
-<H ri5 if(hCallWnd[index]==NULL)
6Uch0xha! continue;
JB641nv if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
L)@`58Eil {
g6HphRJ5s SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
l A 0-?k bProcessed=TRUE;
c,+iU R< }
x4/T?4k }
Bi %Z2/ }
/YS@[\j4 else if((lParam&0xc000ffff)==1){ //有键按下
Jx)~kK switch(wParam)
hYs82P|2Ol {
?=TL2"L case VK_MENU:
+!D=SnBGs MaskBits|=ALTBIT;
*1%e%G break;
@#'yPV1 case VK_CONTROL:
02;f2;I MaskBits|=CTRLBIT;
{(8U8f<'=y break;
YWybPD4\( case VK_SHIFT:
gF$1wV]e MaskBits|=SHIFTBIT;
Ka[Sm|-q break;
0-6:AHix default: //judge the key and send message
XL{{7%j break;
HCI'q\\ }
^U R-#WaQ for(int index=0;index<MAX_KEY;index++){
gNG0k$nP if(hCallWnd[index]==NULL)
B:B0p+$I
continue;
nD^{Q[E6= if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
]t8{)r {
uZo]8mV SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
r _{)?B bProcessed=TRUE;
IptB.bYc }
&\CJg'D:m }
TsoCW]h }
z_5rAlnwT. if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
WV5r$ for(int index=0;index<MAX_KEY;index++){
|_xZ/DT if(hCallWnd[index]==NULL)
ahK?]:&QO continue;
,+swH;=7#r if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
|?4~T: SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
~xsb5M5 //lParam的意义可看MSDN中WM_KEYDOWN部分
Yg\{S<wr }
5]A$P\7~1 }
P]~N-xdV }
fzq'S]+ return CallNextHookEx( hHook, nCode, wParam, lParam );
;$E~ZT4p }
\SoYx5lf *
ePDc' 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:
\<0G
kp FN{H\W1cf BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
(**-"o]HH BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
::^qy^n <DA{\'jJ 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:
1R^XWAb nsM>% +o LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
vWPM:1A {
'Qp&,xK if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
\}]=?}( {
(:</R$I //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
Y3 Pz00x SaveBmp();
AQJ|^'% return FALSE;
wR5\^[GN }
.b!OZ …… //其它处理及默认处理
j\i;'t}8g }
F)[XIY&2/ s0X/1Cq % 8rr*l5 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
-52@%uB TsFV
;Sl3 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
0{^l2?mgSb L@d]R MNv 二、编程步骤
:V5!C$QV -$sl!%HO% 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
K#m\qitb iMOPD}`IX 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
2fHIk57jP !9ceCnwbNN 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
IL8'{<lM i"2J5LLv 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
tWCv]* JN;TGtB^p 5、 添加代码,编译运行程序。
z<3}TD :JTRRv 三、程序代码
L~?,6 ArEH%e ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
)sY$\^'WY #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
;:8jxkx6% #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
e$p1Th*|]4 #if _MSC_VER > 1000
HzgQI #pragma once
?vL^:f[" #endif // _MSC_VER > 1000
}5fI*v #ifndef __AFXWIN_H__
@@&@}IQcR1 #error include 'stdafx.h' before including this file for PCH
j:de}!wc #endif
&\WkJ}&PnA #include "resource.h" // main symbols
H$=h- class CHookApp : public CWinApp
pDq^W@Rq {
b3y,4ke" public:
8`rAE_n`% CHookApp();
i no7!T` // Overrides
^Xt]wl*]+ // ClassWizard generated virtual function overrides
H;b'"./ //{{AFX_VIRTUAL(CHookApp)
P}.yEta public:
]6i_d virtual BOOL InitInstance();
Wj virtual int ExitInstance();
E:dT_x<Y //}}AFX_VIRTUAL
#Kb)>gzT //{{AFX_MSG(CHookApp)
I2Or&
_ // NOTE - the ClassWizard will add and remove member functions here.
$fj"* // DO NOT EDIT what you see in these blocks of generated code !
Hjo:;s //}}AFX_MSG
};VGH/}&s DECLARE_MESSAGE_MAP()
^~YmLI4 };
7y)|^4X2 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
tswG"1R BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
iC5JU&l BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
x9{Sl[2& BOOL InitHotkey();
HPd+Bd BOOL UnInit();
,pGCgOG#}c #endif
.x-Z+Rs{g q9a
wzj //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
RL]lt0O{ #include "stdafx.h"
.@/z-OgXg #include "hook.h"
HpjIp. #include <windowsx.h>
DY+8m8!4H #ifdef _DEBUG
e)
/u>I #define new DEBUG_NEW
yW6[Fpw #undef THIS_FILE
a s<q static char THIS_FILE[] = __FILE__;
Lu#@~ #endif
ytBxe] #define MAX_KEY 100
yrK--C8 #define CTRLBIT 0x04
tKqCy\-q #define ALTBIT 0x02
Um0<I) #define SHIFTBIT 0x01
V;(*\"O #pragma data_seg("shareddata")
Jj^<:t5{rN HHOOK hHook =NULL;
+_|cZlQ& UINT nHookCount =0;
H $qdU!c static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
[#3Cg%V static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
~:RDw<PWp static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
mG8 static int KeyCount =0;
/iJcy:J static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
37M[9m|D* #pragma data_seg()
M@LaD 5 HINSTANCE hins;
KSpC%_LC void VerifyWindow();
:0TSOT9. BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
)1tnZ=& //{{AFX_MSG_MAP(CHookApp)
3K'o&>}L // NOTE - the ClassWizard will add and remove mapping macros here.
me}Gb a // DO NOT EDIT what you see in these blocks of generated code!
dO4U9{+ //}}AFX_MSG_MAP
c_8 mQ END_MESSAGE_MAP()
;HLMU36q ^2?O+ =,F CHookApp::CHookApp()
w\8rh\Mvh {
Y[8co<p // TODO: add construction code here,
smLDm // Place all significant initialization in InitInstance
}RP 9%n^ }
!^"!fuoNC ]@<3 6ByM CHookApp theApp;
|Nx!g fU LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
:Ro"
0/d {
F#37Qv BOOL bProcessed=FALSE;
J'Mgj$T $ if(HC_ACTION==nCode)
5)zh@aJ@ {
IkXKt8`YVA if((lParam&0xc0000000)==0xc0000000){// Key up
|EEz>ci switch(wParam)
F*jjcUk {
'>WuukC case VK_MENU:
/Geks/ MaskBits&=~ALTBIT;
Qmc;s{-r; break;
@v-)|8GdY case VK_CONTROL:
X=c
,`&^ MaskBits&=~CTRLBIT;
z&yb_A:> break;
T[$hYe8%^ case VK_SHIFT:
$^+KR]\q MaskBits&=~SHIFTBIT;
Z-sN4fr a break;
v.^
'x default: //judge the key and send message
kKk |@ break;
&u`rE"" }
#?|1~HC for(int index=0;index<MAX_KEY;index++){
'hHX"\|RA if(hCallWnd[index]==NULL)
2Q_{2(nQb continue;
GHsdLe=t0# if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
!vo '8r?& {
[F-u'h< *l SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
>p#d;wK4_ bProcessed=TRUE;
U@t?jTMBkO }
2D_Vo ])l/ }
tS/APSY }
6%hEs6-R else if((lParam&0xc000ffff)==1){ //Key down
[,?A$Z*Z| switch(wParam)
f+88R=-u6S {
K}*p(1$u case VK_MENU:
k-PRV8WO MaskBits|=ALTBIT;
T+`GOFx break;
O}iKPY8K case VK_CONTROL:
{aa,#B]i MaskBits|=CTRLBIT;
:x5o3xE break;
Pv$"DEXA2 case VK_SHIFT:
bFdg'_ MaskBits|=SHIFTBIT;
d~bH!P break;
snzH}$Ls default: //judge the key and send message
WMz|FFKVY break;
1B]wSvP@ }
G;#t6bk for(int index=0;index<MAX_KEY;index++)
IhKas4 {
`YU:kj<6 if(hCallWnd[index]==NULL)
\7w85$ continue;
nsw8[pk if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
i2R]lE8 {
Kz2^f@5=F SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
,?N_67 bProcessed=TRUE;
V`&*%xgGR }
l{SPV8[i }
dE!=a|Pl }
k)t8J \ if(!bProcessed){
2
]6u
Be for(int index=0;index<MAX_KEY;index++){
2X|jq4 if(hCallWnd[index]==NULL)
- OGy-" continue;
#UnO~IE.m$ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
zSufU2 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
+A3\Hj&W }
szs3x-g }
#Lt+6sa]2@ }
-hV KPIb return CallNextHookEx( hHook, nCode, wParam, lParam );
Q2WrB+/ }
FrM~6A_ ~=]@],{ BOOL InitHotkey()
k 5kX {
iYs?B0*JWK if(hHook!=NULL){
3\~fe/z'I nHookCount++;
3T^dgWXEG return TRUE;
a_MnQ@ }
QF6JZQh< else
F&j|Y>m hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
+GtGyp if(hHook!=NULL)
^7<m lr nHookCount++;
&y wY?ox return (hHook!=NULL);
gM[
J'DMW }
g5N<B+?!i BOOL UnInit()
90k|u'ikOp {
rSCX$ @@F if(nHookCount>1){
`%:(IGxz nHookCount--;
Yzx0 [_'u return TRUE;
>V=@[B(0 }
*J5euA5= BOOL unhooked = UnhookWindowsHookEx(hHook);
"r3s'\ if(unhooked==TRUE){
7n]%`Yb nHookCount=0;
nM}`H'0 hHook=NULL;
$6%;mep }
9rc
n*sm return unhooked;
j@\/]oL^We }
k$- q;VI Eu~wbU"% BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
JU+'UK630 {
>x0lSL0y BOOL bAdded=FALSE;
7}85o
J for(int index=0;index<MAX_KEY;index++){
ai9,4 if(hCallWnd[index]==0){
*%+buHe hCallWnd[index]=hWnd;
f=Y9a$.:M HotKey[index]=cKey;
$ !=:ES HotKeyMask[index]=cMask;
[<$d@}O bAdded=TRUE;
`;GGuJb \ KeyCount++;
dR{
V,H7N break;
6MQ:C'8T&= }
LZ: \V)5+ }
ZO$T/GE6% return bAdded;
5ml}TSMu' }
n:] 1^wX# |H@p^.; BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
glIIJ5d|, {
IcA~f@ BOOL bRemoved=FALSE;
eZ$1|Sj]j for(int index=0;index<MAX_KEY;index++){
{-qTU6 if(hCallWnd[index]==hWnd){
k=
1+mG if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Jtk(yp{Zz hCallWnd[index]=NULL;
H43D=N& HotKey[index]=0;
,6pH *b$ HotKeyMask[index]=0;
N'.+ezZ;h bRemoved=TRUE;
|:BYOxAYZ8 KeyCount--;
j"8N)la break;
izo
$0 }
jo#F& }
Uwa1)Lwn }
~[6|VpGc: return bRemoved;
!qv;F?2
<g }
k] YGD W}3vY] void VerifyWindow()
feHAZ.8rp+ {
*&MkkI# for(int i=0;i<MAX_KEY;i++){
3f8Z?[Bb@ if(hCallWnd
!=NULL){ d69VgLg
if(!IsWindow(hCallWnd)){ L@GD$F=<0
hCallWnd=NULL; ^2@~AD`&h
HotKey=0; (Ad!hyE(
HotKeyMask=0; o|C{ s
KeyCount--; x*)O<K
} ! .}{
f;Ls
} Z_+No :F7I
} `^{P,N>X
} OO>2oH
(DAJ(r~
BOOL CHookApp::InitInstance() 5)6%D
{ +06j+I
AFX_MANAGE_STATE(AfxGetStaticModuleState()); lNAHn<ht
hins=AfxGetInstanceHandle(); WQ`T'k#ESW
InitHotkey(); ij5YV3
return CWinApp::InitInstance(); KR0
x[#.*
} %Ski5q
i*j+<R@
int CHookApp::ExitInstance() `h6W@ROb
{ INpub5
VerifyWindow(); "
z{w^k
UnInit(); _r'M^=yx[
return CWinApp::ExitInstance(); 3J<,2
} {Wo7=aR
U 7?ez
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file H)tDfk sq\
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) F{tSfKy2
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ ~G:7*:[b
#if _MSC_VER > 1000 cw{[B%vw
#pragma once Y?cw9uYB
#endif // _MSC_VER > 1000 |&vuK9q
o5R40["
class CCaptureDlg : public CDialog U)8]pUI+/P
{ O1,[7F.4g
// Construction -}o;Y)
public: _#B/#^a
BOOL bTray; eH{ 9w8~
BOOL bRegistered; 6Tnzg`0I
BOOL RegisterHotkey(); ]9Hy
"#Fz
UCHAR cKey; Ea?.HRxl
UCHAR cMask; Ags`%(
void DeleteIcon(); <&iBR
void AddIcon(); (z7#KJ1+Aw
UINT nCount; *_wBV
M=2
void SaveBmp(); :_*Q
IyW
CCaptureDlg(CWnd* pParent = NULL); // standard constructor 4fswx@l
// Dialog Data Pa<