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:
= 03G~7B>
fQ"Vx! 一、实现方法
0}`.Z03fy [_`yy 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:
g"Hl 30o : O@(Sv #pragma data_seg("shareddata")
1c@S[y HHOOK hHook =NULL; //钩子句柄
h4itXJy52B UINT nHookCount =0; //挂接的程序数目
5(\/ b<# static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
'AWWdz static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
zt9A-%
\R static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
g18zo~LZ static int KeyCount =0;
Nxl#] static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
g~,iWoY #pragma data_seg()
=bP<cC=3b ,SIGfd 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。
|:4W5>sfg }+MA*v[06 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:
^fsC]9NS _g9j_
x:= BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
-DJ,<f*$ cKey,UCHAR cMask)
z79oj\&[ {
As5l36 BOOL bAdded=FALSE;
/&G|.Cx for(int index=0;index<MAX_KEY;index++){
ltU{P|7!E if(hCallWnd[index]==0){
P.Cn[64a+@ hCallWnd[index]=hWnd;
6Y6t.j0vN. HotKey[index]=cKey;
Y1>OhHuN HotKeyMask[index]=cMask;
RTbV!I bAdded=TRUE;
_*g.U=u KeyCount++;
Z8/.I break;
^V9|uHOJoq }
AB0}6g^O }
~.J*_0~Ze return bAdded;
-R1;(n) }
gaNe\ //删除热键
uVhzJu. BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
B 5qy4MFWs {
e2G;_: BOOL bRemoved=FALSE;
pRxVsOb for(int index=0;index<MAX_KEY;index++){
FIAmAZH}_ if(hCallWnd[index]==hWnd){
Isvb;VT9L if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
pbqk hCallWnd[index]=NULL;
T*Ge67 HotKey[index]=0;
-OmpUv-O" HotKeyMask[index]=0;
)+Z.J]$O- bRemoved=TRUE;
b&QI#w KeyCount--;
+\dKe[j{g break;
C2zKt/)A }
FYu30 }
qf ]le]J }
I*JJvqh return bRemoved;
F\&^(EL }
P.k>6T<U> Uc,.. a{}#t} DLL中的钩子函数如下:
ps8tr:T^= /pU`- LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
B<Cg_C {
^.g-}r8, BOOL bProcessed=FALSE;
~,)D
n if(HC_ACTION==nCode)
7I]?:%8h {
x./"SQ=R+ if((lParam&0xc0000000)==0xc0000000){// 有键松开
t5i58@{~ switch(wParam)
%[~g84@ {
-vc$I=b; case VK_MENU:
=\oW{? MaskBits&=~ALTBIT;
9C Ki$L break;
,JbP~2M~% case VK_CONTROL:
m:~y:. MaskBits&=~CTRLBIT;
c68y\ break;
5 A5t case VK_SHIFT:
@e\
@EW MaskBits&=~SHIFTBIT;
_\,lv
\u break;
[h&s<<#
D default: //judge the key and send message
c=?6`m,"M break;
i|,}y`C# }
YwZx{%f for(int index=0;index<MAX_KEY;index++){
4s'%BM-r- if(hCallWnd[index]==NULL)
5{i NR4sq continue;
/[/{m ] if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
$\1M"a}F {
omPxU2Jw SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
/CKn XU; bProcessed=TRUE;
lt]&o0> }
r}Gku0Hu_E }
5&_")k3$* }
'Ox "YE else if((lParam&0xc000ffff)==1){ //有键按下
ZFH-srs{
switch(wParam)
]mNsG0r6 {
L*|P' case VK_MENU:
}.WO=IZ MaskBits|=ALTBIT;
Uugq.'> break;
o
/1+
}f case VK_CONTROL:
TXV^f* MaskBits|=CTRLBIT;
aMkuyqPf{ break;
\UM&|yk: case VK_SHIFT:
8:*ZuR|~ MaskBits|=SHIFTBIT;
7)2Q break;
Rg46V-"d,@ default: //judge the key and send message
(JjxrZ+L break;
9`VY)"rJ }
:9x]5;ma for(int index=0;index<MAX_KEY;index++){
ZWjje6 if(hCallWnd[index]==NULL)
s?k:X ~m continue;
SfrM|o if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
dWi.V?K4z {
L*4=b
(3 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
X_bB6A6 bProcessed=TRUE;
t,0}}9%? }
+7
j/.R }
Lc]hwMGR* }
KjF8T7% if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
%gSmOW2.c^ for(int index=0;index<MAX_KEY;index++){
!Z{7X ^ if(hCallWnd[index]==NULL)
Vu4LC&q continue;
v^p* l0r6: if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
*u,xBC2C SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
k,<7)- //lParam的意义可看MSDN中WM_KEYDOWN部分
]-a/)8 }
[TqX"@4NS }
u}_x }
C8)s6 return CallNextHookEx( hHook, nCode, wParam, lParam );
ni )G }
tux`-F "A~D(1K 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:
=JPY{'V O on5\rY<I:@ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
1~2+w]-kU BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
_F4=+dT| 2S[:mnK 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:
~d,$nZ"z -!M>;M@ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
W>&*.3{v {
8NE[L#k if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
H<g8u{
$ {
|DVFi2 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
u$ o19n SaveBmp();
@(N}
{om return FALSE;
s9+lC!! }
-y3[\zNe …… //其它处理及默认处理
2lN0Sf@ }
[ws;|nh I.~=\%Z{ !mwMSkkq 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。
b`DPlQHj )u]=^ 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。
ZdPqU\G^q _ogN
二、编程步骤
%X%f0J \FCPD.2s+ 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";
i/!KUbt WHLTJ]OB 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
b{x/V 9&| )/OIzbA3# 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;
[{&OcEf >>y\idg&: 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;
f/0k,~,* B(eiRr3 5、 添加代码,编译运行程序。
T0b/txS tF<&R&= 三、程序代码
YT)1_>*\ Su
+<mW ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
NQiu>Sg #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
zNn #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
?Lv U7 #if _MSC_VER > 1000
[{vX*q
3B #pragma once
=W"T=p*j #endif // _MSC_VER > 1000
30s A\TZ #ifndef __AFXWIN_H__
AxO.adQE% #error include 'stdafx.h' before including this file for PCH
qzZ;{>_f
#endif
oGbh* #include "resource.h" // main symbols
"dYT>w class CHookApp : public CWinApp
YETGq- {
W!=ur,F+ public:
U Q)^`Zj CHookApp();
am| 81)|a // Overrides
8 QI+O` // ClassWizard generated virtual function overrides
dV*9bDkM/ //{{AFX_VIRTUAL(CHookApp)
]a*26AbU+ public:
20Jlf?
virtual BOOL InitInstance();
L$, Kdpj virtual int ExitInstance();
cmd7-2 //}}AFX_VIRTUAL
W~l.feW$i //{{AFX_MSG(CHookApp)
#0^a-47PA< // NOTE - the ClassWizard will add and remove member functions here.
N?A}WW# // DO NOT EDIT what you see in these blocks of generated code !
K,P`V
&m? //}}AFX_MSG
~0Zy$L/D DECLARE_MESSAGE_MAP()
N!\1O, };
EVLDP\w{ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
*rV{(%\m BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
v!n|X7 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
6aWnj*dF BOOL InitHotkey();
`Uvc^ BOOL UnInit();
,Vz-w;oDn #endif
"N}MhcdS DwTVoCC //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
4JH^R^O<n
#include "stdafx.h"
`bLJwJ7 #include "hook.h"
9"M-nH*< #include <windowsx.h>
-&%!
4(Je #ifdef _DEBUG
+lf`Dd3 #define new DEBUG_NEW
wjOJn] #undef THIS_FILE
c2Y\bKeN static char THIS_FILE[] = __FILE__;
e%7#e%1s #endif
|a'$v4dCF #define MAX_KEY 100
$HRl:KDdP~ #define CTRLBIT 0x04
(~"#=fs.L #define ALTBIT 0x02
UZ:z|a3 #define SHIFTBIT 0x01
i0?/\@gd #pragma data_seg("shareddata")
E 429<LQI/ HHOOK hHook =NULL;
3_{rXtT)' UINT nHookCount =0;
usi3z9P>n static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
#nj;F'O]( static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
z\WyL ; static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
nLrCy5R: static int KeyCount =0;
lgbq^d static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
srKEtd" #pragma data_seg()
a:1$i dj HINSTANCE hins;
_ vAc/_N void VerifyWindow();
F"'
(i BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
T w1&<S //{{AFX_MSG_MAP(CHookApp)
T*(mi{[T // NOTE - the ClassWizard will add and remove mapping macros here.
I(/*pa?m{ // DO NOT EDIT what you see in these blocks of generated code!
? Z2`f6;W4 //}}AFX_MSG_MAP
=66'33l2 END_MESSAGE_MAP()
*
COC& .GCJA`0h CHookApp::CHookApp()
nH+wU;M {
8>I4e5Ym // TODO: add construction code here,
vnlHUQLO // Place all significant initialization in InitInstance
t7e7q"+/ }
ow'CwOj$ %w/vKB"nO CHookApp theApp;
m1sV~"v; LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
hw B9N {
pqohLA BOOL bProcessed=FALSE;
!bn=b>+ if(HC_ACTION==nCode)
sWVapup? {
&hM7y7 if((lParam&0xc0000000)==0xc0000000){// Key up
9!dG Xq switch(wParam)
+z~bH!$2 {
z6Nz)$!_i case VK_MENU:
J)H*tzg MaskBits&=~ALTBIT;
TCkMJs? break;
Dh68=F0 case VK_CONTROL:
J7kqyo" MaskBits&=~CTRLBIT;
>YcaFnY break;
.kfx\,lgm case VK_SHIFT:
VLbbn MaskBits&=~SHIFTBIT;
(L W2S;- break;
Fgi;% default: //judge the key and send message
!R[~Z7b6 break;
@"aqnj>+ }
c+##!_[9 for(int index=0;index<MAX_KEY;index++){
PJ<9T3Fa if(hCallWnd[index]==NULL)
#w!ewC vt continue;
*}>)E]O@ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
=8Z-ORW51 {
jK{qw SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
5YgT*}L+, bProcessed=TRUE;
Q-yNw0V}F }
{m_y< }
:8A@4vMS)? }
9LSV^[QUH else if((lParam&0xc000ffff)==1){ //Key down
?*~sx=mC switch(wParam)
zu,Yuq {
l4&
l)4Rx case VK_MENU:
T^#d\2 MaskBits|=ALTBIT;
H=mFc@fh break;
Qs<L$"L1 case VK_CONTROL:
;B{oGy. MaskBits|=CTRLBIT;
y#/P||PM break;
E<@N4%K_Q case VK_SHIFT:
-'^:+FU MaskBits|=SHIFTBIT;
KppYe9? break;
2g5jGe*0 default: //judge the key and send message
n.G.fbO break;
[|\#cVWs }
KC8 for(int index=0;index<MAX_KEY;index++)
Io{BO.K*Y {
!L2!:_ if(hCallWnd[index]==NULL)
64Tb,AL_ continue;
?gMq:[XN if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
y-~_ W 6\ {
Us%g&MWdpb SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
uF[~YJ> bProcessed=TRUE;
+&<k}Mz }
I
|"' }
bR?xz-g%<3 }
f @Vd'k< if(!bProcessed){
2dDhO for(int index=0;index<MAX_KEY;index++){
WwxV}?Cf+ if(hCallWnd[index]==NULL)
@c).&7 continue;
yqP=6 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
*Xh#W7,< SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
!iK{q0 }
CXTtN9N9 }
6;(b-Dhi }
#JN4K>_4 return CallNextHookEx( hHook, nCode, wParam, lParam );
i\x@s>@x} }
xWM?E1@ n"@){:{4? BOOL InitHotkey()
h+j*vX/! {
& u6ydN1xe if(hHook!=NULL){
9I''$DVf nHookCount++;
S#T u/2<} return TRUE;
~Q}!4LH }
\~l" else
PO,zP9 hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
wn\R|'Rdz if(hHook!=NULL)
VLoRS) nHookCount++;
s}bLA>~Ta return (hHook!=NULL);
>'jkL5l }
QvJ29 BOOL UnInit()
xE!b) @>S {
S WyJ` if(nHookCount>1){
SH O&:2 nHookCount--;
~(:0&w%e return TRUE;
DQ c pIV }
N1"bH~ BOOL unhooked = UnhookWindowsHookEx(hHook);
D$E#:[ if(unhooked==TRUE){
FU;a
{irB nHookCount=0;
"Jdi>{o8 hHook=NULL;
o'8%5M@ }
}rF4M1+B\ return unhooked;
TV`sqKW }
^oNcZK> 9_~9?5PU BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
\[%_ :9eq {
_joW%`T8 BOOL bAdded=FALSE;
Y=y
0`?K for(int index=0;index<MAX_KEY;index++){
p(9[*0.}; if(hCallWnd[index]==0){
qggRS)a hCallWnd[index]=hWnd;
IYa(B+nB) HotKey[index]=cKey;
e*d lGK3l HotKeyMask[index]=cMask;
A+FQmLS bAdded=TRUE;
X1BqN+=@9 KeyCount++;
Dn#UcMO>W break;
O9N+<sU=X }
C'S_M@I= }
TP)o0U return bAdded;
j,z)x[3} }
OF:0jOW
ZP-9KA$" BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
]cWQ9 {
D%6}x^`Qk BOOL bRemoved=FALSE;
(!Xb8rV0_ for(int index=0;index<MAX_KEY;index++){
VFm)!'=I if(hCallWnd[index]==hWnd){
KcW 5 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Q5_ ,`r` hCallWnd[index]=NULL;
15%6;K?b HotKey[index]=0;
w{N8Y~O HotKeyMask[index]=0;
<N3~X,ch bRemoved=TRUE;
;alt% :$n KeyCount--;
~RZN+N break;
^==Tv+T9U }
JOs
kf( }
{wO.nOB }
rd"!&i return bRemoved;
j HObWUX }
B[2t.d;h N
x^JC_ void VerifyWindow()
E,ooD3$h {
Mgu9m8
`J for(int i=0;i<MAX_KEY;i++){
;ZkY[5 if(hCallWnd
!=NULL){ [jEA|rd~}
if(!IsWindow(hCallWnd)){ qLw^Qxo
hCallWnd=NULL; -iFFXESVX
HotKey=0; *z_`$Y
HotKeyMask=0; =5:kV/p
KeyCount--; 6j|~oMYP
} ~{N#JOY}Z
} z]=Ks_7
} NdRE,HWd?$
} q6x}\$mL
:`0,f ?cE
BOOL CHookApp::InitInstance() P]L%$!g
{ 8:uh0
AFX_MANAGE_STATE(AfxGetStaticModuleState()); )QmmI[,tq
hins=AfxGetInstanceHandle(); gV*4{d`
InitHotkey(); -w'g0/fD
return CWinApp::InitInstance(); '
-aLBAxy
} TGjxy1A
XjYMp3
int CHookApp::ExitInstance() }g[Hi`
{ <,H/7Ba
VerifyWindow(); !#E-p?O.
UnInit(); >xH?`I7;f
return CWinApp::ExitInstance(); y5VohVa`
} :R3&R CTZ
U@(8)[?nxn
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file /gn\7&