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:
-/O_wqm#
?^<
E#2a 一、实现方法
[A.ix}3mm scsN2#D7U/ 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:
I!L`W
_ l; ._
?H #pragma data_seg("shareddata")
T|{1,wP HHOOK hHook =NULL; //钩子句柄
A=z+@b6 UINT nHookCount =0; //挂接的程序数目
#nv =x&g static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
("7rjQjRz static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
P&s-U6 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
yi*2^??`
1 static int KeyCount =0;
el;ey Ga static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
#Pf?.NrTn #pragma data_seg()
"GTlJqhk _8f?
H#& 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。
VT;Vm3\ qkEre 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:
?Bdhn{_ !FqJP
OGm BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
/g_cz&luR cKey,UCHAR cMask)
zB?} {@ {
p:GB"e9>H BOOL bAdded=FALSE;
LL}|#%4d for(int index=0;index<MAX_KEY;index++){
r}1.=a if(hCallWnd[index]==0){
Bv)^GU& hCallWnd[index]=hWnd;
S{q c1qj HotKey[index]=cKey;
1j9R^ HotKeyMask[index]=cMask;
d3nMeAI AO bAdded=TRUE;
8)wxc1 KeyCount++;
FKX+
z break;
:?*|D p1 }
gyt[ZN_2 }
/5l"rni return bAdded;
GbLuXU }
|A'y|/)#Z //删除热键
<yw6Om:n< BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
xE2sb* {
&RzkM4" BOOL bRemoved=FALSE;
WB7pdSZ for(int index=0;index<MAX_KEY;index++){
'nrXRDb if(hCallWnd[index]==hWnd){
gB;5&;T: if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
#%;QcDXRe hCallWnd[index]=NULL;
/oWn0 HotKey[index]=0;
eYN=? HotKeyMask[index]=0;
/*zngp@ bRemoved=TRUE;
oV(|51(f KeyCount--;
X4c|*U=4 break;
)dv w.X }
_5nS!CN }
8%@![$q<g }
aw\\oN* return bRemoved;
LR:v$3 G( }
a+U^mPe *CIR$sS V+A9.KoI DLL中的钩子函数如下:
G<2OL#Y- S[2uez` LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
g?e$B}% {
&$1ifG BOOL bProcessed=FALSE;
;yvx - if(HC_ACTION==nCode)
!R;NV|.eI6 {
JZa^GW:YQh if((lParam&0xc0000000)==0xc0000000){// 有键松开
rkF>c switch(wParam)
fbG+.' {
`Mh3v@K: case VK_MENU:
@d+NeS MaskBits&=~ALTBIT;
lR[]A break;
K~C6dy
case VK_CONTROL:
P1r)n{; MaskBits&=~CTRLBIT;
vky@L! &, break;
D<16m<b case VK_SHIFT:
,esryFRG MaskBits&=~SHIFTBIT;
K4G43P5q` break;
g+X .8>= default: //judge the key and send message
2ncD,@ij break;
d7f{2 }
4R(H@p%+r2 for(int index=0;index<MAX_KEY;index++){
1I=>0c if(hCallWnd[index]==NULL)
2@A%;f0Q continue;
t-gLh(-. if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
yGxAur=dE {
o4^|n1vN SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
kK,Ne%}a2K bProcessed=TRUE;
V!{}%;f }
fj7\MTy }
K+s@.D9J }
SU,#:s( else if((lParam&0xc000ffff)==1){ //有键按下
^n @dC? switch(wParam)
5~pQ$- {
!Qqi% case VK_MENU:
eTeZ^G MaskBits|=ALTBIT;
ef Moi 'v break;
nT;Rwz$3 case VK_CONTROL:
**D3.-0u& MaskBits|=CTRLBIT;
NMM$
m!zg break;
UdiogXZ case VK_SHIFT:
,:E*Mw: MaskBits|=SHIFTBIT;
__3s3YG break;
NrVE[Z# default: //judge the key and send message
}Ai_peO0a break;
T"b'T>Y }
M MQ^&!H for(int index=0;index<MAX_KEY;index++){
BidTrO if(hCallWnd[index]==NULL)
MXsCm( continue;
mBrH`! if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
@U 6jd4?) {
+sW;p?K7eO SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
5Al1u|;HB bProcessed=TRUE;
N4xCZb }
SqF `xw }
H;~Lv;,g, }
|#Gug(' if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
F=B[%4q`% for(int index=0;index<MAX_KEY;index++){
pGsk[. if(hCallWnd[index]==NULL)
k6}M7&nY continue;
*K57($F if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
mRNA ,* SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
mr6 ~8I //lParam的意义可看MSDN中WM_KEYDOWN部分
EZY <k# }
P,eP>55'K }
FJ/c(K }
-PG81F&K return CallNextHookEx( hHook, nCode, wParam, lParam );
^D%hKIT }
&tJ!cTA.- j@Ta\a-,x 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
Vq IzDs r'bPSu, BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
UqA<rW BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
}MiEbLduN 7eR%zNDa 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
Z)7|m <Wwcd8d LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
N,4. %|1 {
dPm_jX if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
G2[?b2)8 {
)@Vz,f\} //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
k$ORV U SaveBmp();
\{@n>Mh return FALSE;
Gkr]8J }
`xq/<U;i …… //其它处理及默认处理
Fs3rsig }
I&Z4?K Rt9S -Gyj]v5y`c 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。
Cd7imj YjR`}rdwo 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。
}t FRl M}S1Zz%Ii1 二、编程步骤
om1@;u8u %FhUjHm 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";
nn?h;KzB y!kU0 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
Q`B K
R]/ %@~;PS3kd 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;
TpH-_ft L|*0
A=6 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;
DTMoZm F*['1eAmdY 5、 添加代码,编译运行程序。
11g_!X -g@ I;g>r8N-Bu 三、程序代码
v.q`1D1=t 0zHMtC1, ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
|lG7/\A #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
J/(^Z?/~P! #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
/7CV7=^d, #if _MSC_VER > 1000
EW~M,+? #pragma once
b3M`vJ+{ #endif // _MSC_VER > 1000
?nCo?A #ifndef __AFXWIN_H__
w2(pgWed #error include 'stdafx.h' before including this file for PCH
JGRL&MG4 #endif
Oj,v88= #include "resource.h" // main symbols
xo.k:F class CHookApp : public CWinApp
iRIO~XVo {
)7jJ3G* public:
xCYK"v6\ CHookApp();
4c'F.0^ // Overrides
i!i=6m.q7 // ClassWizard generated virtual function overrides
WcOnv'l, //{{AFX_VIRTUAL(CHookApp)
+.2OZ3( public:
Q^{XM virtual BOOL InitInstance();
7@NV|Idtd virtual int ExitInstance();
/Pyj|!C3`q //}}AFX_VIRTUAL
!zZ3F|+HB //{{AFX_MSG(CHookApp)
8 t5o&8v // NOTE - the ClassWizard will add and remove member functions here.
-FGM>~x // DO NOT EDIT what you see in these blocks of generated code !
/7fD;H^* //}}AFX_MSG
'5xvR G DECLARE_MESSAGE_MAP()
t}wwRWo2?f };
dZ,IXA yB LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
wsEOcaie BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
Tv6HPD$[ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
oWb\T
2!m BOOL InitHotkey();
nXT/zfS BOOL UnInit();
F.cKg~E|e #endif
V=de3k&p pdySip< //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
tu:W1? #include "stdafx.h"
'D:R]@eK] #include "hook.h"
$V\Dl]a1 #include <windowsx.h>
UGD B4S #ifdef _DEBUG
Ow50M;E #define new DEBUG_NEW
;@FCaj& #undef THIS_FILE
]J^/`gc static char THIS_FILE[] = __FILE__;
{ u %xc"0y #endif
%}}?Y`/W) #define MAX_KEY 100
x+8%4]u` #define CTRLBIT 0x04
p~3 (nk<+ #define ALTBIT 0x02
C7=N`s} #define SHIFTBIT 0x01
,.z?=]'en #pragma data_seg("shareddata")
NA!?.zn HHOOK hHook =NULL;
eqSCE6r9x UINT nHookCount =0;
qx1+' static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
^e{]WH? static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
zhgvqg- static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
\ OW.?1d static int KeyCount =0;
{WvYb, static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
{`ByZB #pragma data_seg()
\#!B*:u HINSTANCE hins;
U62Z ?nge% void VerifyWindow();
{HtW`r1)Tt BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
4Ifz-t/ //{{AFX_MSG_MAP(CHookApp)
`rest_vu // NOTE - the ClassWizard will add and remove mapping macros here.
u\q(v D. // DO NOT EDIT what you see in these blocks of generated code!
f=IF_|@^S //}}AFX_MSG_MAP
):]5WHYg END_MESSAGE_MAP()
vyvb-oz;u L]*5cH CHookApp::CHookApp()
G$[Hm\V {
-)Hc^'. // TODO: add construction code here,
{_R{gpj' // Place all significant initialization in InitInstance
Ei4Iv#Oi` }
( _3QZ ^6QzaC3 CHookApp theApp;
`b KJ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
KU^|T2s% {
jx#9
BOOL bProcessed=FALSE;
yioX^`Fc(~ if(HC_ACTION==nCode)
)4R[C={ {
g=$nNQ
\6= if((lParam&0xc0000000)==0xc0000000){// Key up
Z.b?Jzj switch(wParam)
ny}_^3 {
! NJGW case VK_MENU:
"0Z5cQjg MaskBits&=~ALTBIT;
'?Xf(6o1 break;
uN=f(-" case VK_CONTROL:
VA@ MaskBits&=~CTRLBIT;
aUi^7;R&< break;
>c$3@$ case VK_SHIFT:
~U4Cf > MaskBits&=~SHIFTBIT;
Pa'N)s< break;
|j4p default: //judge the key and send message
i3cMRcS; break;
|$Cfm} }
1}~ZsrF for(int index=0;index<MAX_KEY;index++){
Z>[n~{-,p if(hCallWnd[index]==NULL)
aF[#(PF continue;
BP@V:z if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
0jt@|3 {
dKY#Tl] SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
-^JPY)\R bProcessed=TRUE;
A{Qo}F<* }
a-lF}P\ }
kDG?/j90D }
/!sGO: else if((lParam&0xc000ffff)==1){ //Key down
Ya}}a switch(wParam)
a@-bw4SD {
T^ - - :1 case VK_MENU:
,<$rSvMfg MaskBits|=ALTBIT;
}:S}jo7 break;
;B!p4hu case VK_CONTROL:
N|%X/UjZ2. MaskBits|=CTRLBIT;
+R_s(2vz break;
_zkTx7H case VK_SHIFT:
l{Et:W%| MaskBits|=SHIFTBIT;
8Vy/n^3) break;
m95]
z18T' default: //judge the key and send message
NU"L1dK
@ break;
F_&H*kL L3 }
)d>Dcne for(int index=0;index<MAX_KEY;index++)
,ZVhL* " {
}}l jVUpC% if(hCallWnd[index]==NULL)
s^k<r;'\ continue;
.LGA0 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Rq`5ff3, {
`Ue5;<K-/ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
j
Y(|z*| bProcessed=TRUE;
]MC5 uKn }
[#fz[U }
3_>=Cv} }
o wwWm1@ if(!bProcessed){
!b$]D?=} for(int index=0;index<MAX_KEY;index++){
I|Mw*2U if(hCallWnd[index]==NULL)
'wWuR@e#& continue;
sq@c?!' if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
(w vU;u SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
q.j$]?PQ }
C=bQ2t=Z }
U;M! jj }
)$K\:w> return CallNextHookEx( hHook, nCode, wParam, lParam );
ZiRCiQ/? }
k"6v& O |E;+j\ BOOL InitHotkey()
0U !&|i\ {
-j@IDd7 if(hHook!=NULL){
3S1{r
)[j nHookCount++;
~%h&ELSw return TRUE;
J ~KygQ3% }
v5&W)F else
KL*+gq0k hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
cC]]H&'Hg+ if(hHook!=NULL)
i(*fv(z nHookCount++;
$LG.rJ/* return (hHook!=NULL);
ENI|e,'[ }
|XMWi/p BOOL UnInit()
,!X:wY}dW {
["e;8H[K)% if(nHookCount>1){
umt`0m. : nHookCount--;
..w$p-1 return TRUE;
"
t?44[ }
Hz=s)6$ey BOOL unhooked = UnhookWindowsHookEx(hHook);
*?VB/yO=0 if(unhooked==TRUE){
~6+Um_A_L nHookCount=0;
c:+UC hHook=NULL;
H%Z;Yt8^gt }
hLVgP&/E return unhooked;
shO4>Ha }
D[6wMep^n ",' Zr<T BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
V;Q@'<w {
Wys$#pJ BOOL bAdded=FALSE;
#4!f/dWJp for(int index=0;index<MAX_KEY;index++){
rV2>;FG if(hCallWnd[index]==0){
foB&H;A4oC hCallWnd[index]=hWnd;
m)]|mYjju HotKey[index]=cKey;
Vy^mEsQC+h HotKeyMask[index]=cMask;
@1U6sQ bAdded=TRUE;
[z6P]eC7 KeyCount++;
:Zo^Uc:*w break;
b<[]z, }
eR/X9< }
,b?G]WQrHs return bAdded;
:a:m>S<~ }
+n)bWB% rB|4 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
jo<Gf 5 {
6/vMK<Fz9 BOOL bRemoved=FALSE;
!& >LLZ for(int index=0;index<MAX_KEY;index++){
'Mhnu2d if(hCallWnd[index]==hWnd){
ylDfr){ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
= )4bf"~8 hCallWnd[index]=NULL;
8#9OSupp HotKey[index]=0;
Cv/3-&5S HotKeyMask[index]=0;
Ns#L9T# bRemoved=TRUE;
!3o/c w9 KeyCount--;
C4t~k break;
EW3--33s }
/Xv@g$ }
y)TBg8Q }
Bo1 t}#7 return bRemoved;
,dFY] }
=vDpm, l{VJaZ $M void VerifyWindow()
07:h4beT {
#-{ljjMQI for(int i=0;i<MAX_KEY;i++){
G^SDB!/@J if(hCallWnd
!=NULL){ NE3/>5
if(!IsWindow(hCallWnd)){ '#~Sb8
hCallWnd=NULL; z6h/C{
HotKey=0; ]BTISaL-R
HotKeyMask=0; u'gsIuRJ
KeyCount--; 6UuM`eu
} |uX&T`7?-
} }.=@^-JBA5
} AJ6O>Euq
} l1%*LyD
ZmI#-[/
BOOL CHookApp::InitInstance() QkLcs6)R
{ NH1ak(zHW
AFX_MANAGE_STATE(AfxGetStaticModuleState()); y5Fgf3P@ju
hins=AfxGetInstanceHandle(); IVeA[qA0
InitHotkey(); ,S~A]uH'
return CWinApp::InitInstance(); 4 XGEw9`3
} jO`L:D/C
fSGaUBiq}
int CHookApp::ExitInstance() a)6?:nY$
{ }VVtv1
VerifyWindow(); faZc18M^1
UnInit(); ?}jjBJ&
return CWinApp::ExitInstance(); 6'e 'UD
} O<XNI(@
6+C]rEY/o
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file db3.X~Cn#s
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 'lgS)m
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ W;U<,g
'
#if _MSC_VER > 1000 N'|9rB2e
#pragma once ZJ[p7XP
#endif // _MSC_VER > 1000 "L9pFz</
U]ZI_[\'U
class CCaptureDlg : public CDialog \tdYTb.
{ '[bw7T
// Construction rKl
public: :z$+leNH\
BOOL bTray; 8P&z@E{y
BOOL bRegistered; Qr?(2t#
BOOL RegisterHotkey(); 9Dyy&$s
UCHAR cKey; (D\`:1g
UCHAR cMask; [&zSY