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:
_,IjB/PR(
}r@yBUW 一、实现方法
7?{y&sf @$'pMg 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
TiF+rA{t 3+(lKd #pragma data_seg("shareddata")
)(_NFpM HHOOK hHook =NULL; //钩子句柄
-e_op'` UINT nHookCount =0; //挂接的程序数目
Js vdC]+ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
!Q*w] static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
xVgm 9s$"c static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
Y}:4y$< static int KeyCount =0;
P+=m. static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
A^#\=ZBg1 #pragma data_seg()
;8dffsyq ;Rpib[m 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
3W]gn8 f*xr0l DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
:0QDV~bs T\g+w\N BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
CWocb=E cKey,UCHAR cMask)
3u& ,3: {
GC' e BOOL bAdded=FALSE;
ir"t@"Y;o for(int index=0;index<MAX_KEY;index++){
vhAgX0k if(hCallWnd[index]==0){
a2tEp+7? hCallWnd[index]=hWnd;
&0tW{-Hv" HotKey[index]=cKey;
aKWxL e HotKeyMask[index]=cMask;
^g5E&0a`g bAdded=TRUE;
0zkMRBe KeyCount++;
{u2Zl7]z^ break;
)Jdku}Pf }
\$*CXjh3G }
t$wbwP return bAdded;
>TY;l3ew }
_U-`/r o //删除热键
9}m?E<6& BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
GBT|1c'i {
!|UX4 BOOL bRemoved=FALSE;
X^K^az&L for(int index=0;index<MAX_KEY;index++){
{-8Nq`w if(hCallWnd[index]==hWnd){
'Grii, if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ge:a{L hCallWnd[index]=NULL;
&)gc{(4$ HotKey[index]=0;
=y _KL HotKeyMask[index]=0;
)GAlj;9A$ bRemoved=TRUE;
xr7}@rq"U< KeyCount--;
Dmr*Lh~ break;
ydo9 P5E }
rq4g~e!S }
_#NibW }
iC/*d return bRemoved;
6lv@4R^u }
u}|v;:|j #v<`|_ "YY<T&n DLL中的钩子函数如下:
v_Sa0}K9 1*2ycfa LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
CuvY^[" {
!'p<Kh[i BOOL bProcessed=FALSE;
@uCi0P t if(HC_ACTION==nCode)
jH!;}q {
KFwuz()7 if((lParam&0xc0000000)==0xc0000000){// 有键松开
6p*X8j3pW switch(wParam)
rDhQ3iCqo {
?]$<Ufr case VK_MENU:
Qn.dL@W MaskBits&=~ALTBIT;
ZY]$MZf5yo break;
^4+NPk
case VK_CONTROL:
kN
Ll|in@ MaskBits&=~CTRLBIT;
6QCVi break;
W"\}## case VK_SHIFT:
J8p; 1-C" MaskBits&=~SHIFTBIT;
n]`]gLF\i break;
#IvKI+" default: //judge the key and send message
GdI,&|/ break;
'ia-h7QWS }
{?0'(D7. for(int index=0;index<MAX_KEY;index++){
%UrNPk if(hCallWnd[index]==NULL)
I`X!M!dB) continue;
[`b,SX
x if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
gac31,gH {
+]A,fmI. SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
rzIWQFv bProcessed=TRUE;
@Kz,TP!%A }
">CRFee0 }
; F'IS/ttX }
gv>DOez/ else if((lParam&0xc000ffff)==1){ //有键按下
jVd`J switch(wParam)
"Gp Tmu? {
w01[oU$x= case VK_MENU:
Tp?IK_ MaskBits|=ALTBIT;
`gx\m=xG break;
$q:l \ case VK_CONTROL:
*3`R W<Z MaskBits|=CTRLBIT;
H'zAMGZa break;
#p>&|I case VK_SHIFT:
wGNEb MaskBits|=SHIFTBIT;
h~\k;ca break;
Si]?4:E7= default: //judge the key and send message
9 da=q break;
(WC
=om }
[mu8V+8@d4 for(int index=0;index<MAX_KEY;index++){
#$xtUCqX if(hCallWnd[index]==NULL)
slPr^) continue;
~6n|GxR.[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
PiM(QR {
i@nRZ$ K SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
iKE&yO3 bProcessed=TRUE;
Awxm[:r>^ }
N^$q;% }
#%k_V+o3 }
8c-ys-"# if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
s 0Uid&qE for(int index=0;index<MAX_KEY;index++){
e}yF2|0FD if(hCallWnd[index]==NULL)
(0q`eO2 continue;
z2YYxJc&w if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
!~9ASpqvPy SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
O=7S=Rm4& //lParam的意义可看MSDN中WM_KEYDOWN部分
3WF]%P%
}
=Pw{1m|k }
$I*}AUp
v? }
,.p
36ZLP return CallNextHookEx( hHook, nCode, wParam, lParam );
Ve%ua]qA }
U<0Wa>3zj 8(Te^] v# 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:
xaVX@ 3r.3 >8I~i:hn BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
3]?='Qq.( BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Ebs]]a>PO "zJ xWXI 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:
k1xx>=md|C Nmz5:Rq LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
j%
7Gje[ {
lqOpADLS3 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
E/oLE^yL {
ME]4tu //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
onSt%5{P%X SaveBmp();
?wG return FALSE;
i
/[{xRXiR }
z3i`O
La …… //其它处理及默认处理
`)y
;7%- }
DSRc4|L i4D]> ^UKY1Q. 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。
C;HEvq7 $7Hwu^c( 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
v\6.#>NQ ##Pzc~xSn 二、编程步骤
I2CI9,0 jy.L/s 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
'XKfKv >; A"M;kzAfHM 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
z_xy*Iif qzxWv5UH 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
5A`>3w{3n 0Sd>*nC 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
w}l^B>Zz 1$E [`` n 5、 添加代码,编译运行程序。
/]z#V' Fz(;Eo3 三、程序代码
153*b^iDBh 18%$Z$K, ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
A,EG0yb #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
8Gy]nD #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
2EpQ(G
J #if _MSC_VER > 1000
vzI>:Bf #pragma once
i=n;rT #endif // _MSC_VER > 1000
liPrxuP` #ifndef __AFXWIN_H__
L@[}sMdq( #error include 'stdafx.h' before including this file for PCH
V)~b+D #endif
3l~7 #include "resource.h" // main symbols
1YMi4. class CHookApp : public CWinApp
=p[Sd*d {
%IVM1 public:
paV1o>_Rd CHookApp();
b*h:e.q // Overrides
o'$- // ClassWizard generated virtual function overrides
2( GYk //{{AFX_VIRTUAL(CHookApp)
i`l;k~rP public:
-
i2^ eZl virtual BOOL InitInstance();
h='&^1 virtual int ExitInstance();
""
^n^$ //}}AFX_VIRTUAL
/7Sg/d%c //{{AFX_MSG(CHookApp)
U~yPQ8jD // NOTE - the ClassWizard will add and remove member functions here.
wS|k3^OV% // DO NOT EDIT what you see in these blocks of generated code !
(G+)v[f //}}AFX_MSG
:^?-bppYW DECLARE_MESSAGE_MAP()
Ou4hAm91s };
,ov$`v LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
OjffN'a+N BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
-:_3N2U=+ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
b)Nd}6}<? BOOL InitHotkey();
Z:h'kgG & BOOL UnInit();
\PN*gDmX #endif
Mj>QV(L8t e/g9r //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
6bj77CoB #include "stdafx.h"
fI;nVRfp #include "hook.h"
aj1g9y #include <windowsx.h>
"kcix!}& #ifdef _DEBUG
[Y`E"1f2 #define new DEBUG_NEW
lQ^"-zO4 #undef THIS_FILE
*N
~'0"# static char THIS_FILE[] = __FILE__;
=jm\8sl~~ #endif
/<T{g0s #define MAX_KEY 100
w]xr
~D+ #define CTRLBIT 0x04
#lMIs4i. #define ALTBIT 0x02
8v/,<eARJ #define SHIFTBIT 0x01
MX#LtCG#V #pragma data_seg("shareddata")
=[aiW|Y HHOOK hHook =NULL;
A?n5;mvq# UINT nHookCount =0;
bydI+pVMo static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
PyI"B96gz static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
e9'0CH< static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
DQu)?Rsk static int KeyCount =0;
s^PsA9EAn static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
9UteD@* #pragma data_seg()
<6.`(isph HINSTANCE hins;
X^&--@l}T! void VerifyWindow();
f\$_^dV BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
cY!Pv //{{AFX_MSG_MAP(CHookApp)
6:QlHuy0nH // NOTE - the ClassWizard will add and remove mapping macros here.
t; #@t/` // DO NOT EDIT what you see in these blocks of generated code!
WS4DzuZZ //}}AFX_MSG_MAP
*7*cWO= END_MESSAGE_MAP()
*=O3kUoL UnVa`@P^:G CHookApp::CHookApp()
>u0XV "g$ {
4yTgH0(T // TODO: add construction code here,
R9- mq;u+ // Place all significant initialization in InitInstance
p {.6 }
fbdpDVmpU
N8x&<H CHookApp theApp;
.P5'\ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
hd/'>]
{
@[\zO'| BOOL bProcessed=FALSE;
0RSzDgX if(HC_ACTION==nCode)
3e-E/6zH6 {
e+#k\x if((lParam&0xc0000000)==0xc0000000){// Key up
Ht}?=ZzW switch(wParam)
v`Y{.>[H[ {
Vy/G-IASb case VK_MENU:
$mAyM+ ph[ MaskBits&=~ALTBIT;
dqBN_P% break;
/9SoVU8 case VK_CONTROL:
\AI-x$5R* MaskBits&=~CTRLBIT;
7$0bgWi break;
o+k*ia~Fa case VK_SHIFT:
=_N$0 MaskBits&=~SHIFTBIT;
!w/fwOo break;
VS`{k^^ default: //judge the key and send message
o)b-fAd@$ break;
S1~EJa5H }
<f)T*E^5% for(int index=0;index<MAX_KEY;index++){
'Zex/:QS if(hCallWnd[index]==NULL)
sc-h O9~k continue;
qOQ8a:]? if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
H;AMRL o4z {
%)d7iT~M SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
`25<;@ bProcessed=TRUE;
9zx9t }
p74Nd4U$s }
Hd-g|'^K
}
805oV(- else if((lParam&0xc000ffff)==1){ //Key down
4kV$JV.l switch(wParam)
(t@!0_5 {
C*RPSk case VK_MENU:
e `JWY9% MaskBits|=ALTBIT;
N3KI6p6 \ break;
hhU\$'0B- case VK_CONTROL:
%ib7)8Ki0 MaskBits|=CTRLBIT;
z wwJyy%/ break;
x{G 'IEf case VK_SHIFT:
f4 +P2j MaskBits|=SHIFTBIT;
]TtID4qL break;
muK.x7zyl default: //judge the key and send message
s6}SdmE break;
F]N?_ bo }
\?Xoa"^ for(int index=0;index<MAX_KEY;index++)
9@Cu5U] {
eQ[}ALIq if(hCallWnd[index]==NULL)
;jPiD`Kyv continue;
5w~J"P6jg if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
c;a<nTLn {
V4n;N SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
oxnI/Z bProcessed=TRUE;
+l]>(k.2 }
%'X7T^uE }
k7sD"xR3 }
p7izy$Wc if(!bProcessed){
f"AT@Ga] for(int index=0;index<MAX_KEY;index++){
y
La E] if(hCallWnd[index]==NULL)
Be\@n xV[ continue;
Jko=E
if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
r/)ZKO, SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
<4zSh3 }
d}|z+D }
r AqS;@]0 }
QaA?UzB return CallNextHookEx( hHook, nCode, wParam, lParam );
u2fp~.'P }
?V~vP%1 ) 3f\H BOOL InitHotkey()
q^ &r<i {
"HH<5M if(hHook!=NULL){
!`W0;0'Zg nHookCount++;
#_IuB) qy return TRUE;
{+Wknm% }
S
{+Z.P else
el2<W=^M hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
$|[N3 if(hHook!=NULL)
PAC=LQn& nHookCount++;
#2Vq"Zn return (hHook!=NULL);
p)m5|GH24 }
w~=xO_% BOOL UnInit()
#IDLfQ5g {
*L Y6hph" if(nHookCount>1){
O OABn* nHookCount--;
bkpN`+c return TRUE;
<{YzmN\Z }
zITxJx BOOL unhooked = UnhookWindowsHookEx(hHook);
/Ah'KN|EN if(unhooked==TRUE){
NweGK nHookCount=0;
im)r4={
9 hHook=NULL;
(WY9EJ<s, }
v:w^$]4 return unhooked;
/3sX>Rj }
'0o^T 7C 6rCUq
BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
*]Cyc< {
Rz&}e@stl BOOL bAdded=FALSE;
,Qo:]Mj for(int index=0;index<MAX_KEY;index++){
>'WTVj ` if(hCallWnd[index]==0){
xwHE,ykE hCallWnd[index]=hWnd;
c7WOcy@M HotKey[index]=cKey;
ZnuRy: HotKeyMask[index]=cMask;
'*@=SM bAdded=TRUE;
#i*PwgC%_ KeyCount++;
\O,yWyU4 break;
q['3M<q }
}5$le] }
Yn?Xo_Y return bAdded;
U.I7p }
376z~ lh XD9ed BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Tfv@oPu {
p u?COA BOOL bRemoved=FALSE;
}w>UNGUMh for(int index=0;index<MAX_KEY;index++){
$
)2zz>4 if(hCallWnd[index]==hWnd){
pbwOma2 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
7*WO9R/ hCallWnd[index]=NULL;
7:JGr O HotKey[index]=0;
b+f
' HotKeyMask[index]=0;
q& KNK bRemoved=TRUE;
1>2
/1> KeyCount--;
S&'s/jB break;
e(&u3 #7Nn }
)Q}Q -Zt }
h\~!!F }
+;oR_]l return bRemoved;
}6{00er }
fgF@ x /V]i3ac void VerifyWindow()
&arJe!K {
gnb+i` for(int i=0;i<MAX_KEY;i++){
_,e4?grP# if(hCallWnd
!=NULL){ G<`(d@g
if(!IsWindow(hCallWnd)){ rH\oFCzC
hCallWnd=NULL; R'atg
9
HotKey=0; f^IB:e#j;
HotKeyMask=0; e~R_ bBQ0
KeyCount--; a6It1%a+
} MFWkJbZV
} y;P%=MP
} V;Ln|._/t
} [`bK {Dq2
E2`9H-6e
BOOL CHookApp::InitInstance() {aK3'-7
{ )}_}D+2
AFX_MANAGE_STATE(AfxGetStaticModuleState()); l>(*bb1}b
hins=AfxGetInstanceHandle(); bh sCeH
InitHotkey(); 4TiHh
return CWinApp::InitInstance(); ]ZI@?H?
O
} )g]A
'A=
B=}QgXg
int CHookApp::ExitInstance() &Rz