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:
k[;(@e@c
9y5nG 一、实现方法
ewzZb*\ mi$*,fz 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
~JxAo\2i #kL4Rm; #pragma data_seg("shareddata")
e=EM07z HHOOK hHook =NULL; //钩子句柄
L9(!L$ UINT nHookCount =0; //挂接的程序数目
bY7~b/ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
^1w*$5YI static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
@P}!mdH1 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
rJ_fg$.< static int KeyCount =0;
'5m`[S-IU static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
'Lv>!s 7 #pragma data_seg()
/,#&Htk :TN^}RML 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。
p+d?k"WN? ;l2pdP4jf 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:
pbb6?R, 'Gds?o8 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
\H$j["3 cKey,UCHAR cMask)
L#NW<T {
X| X~|&j BOOL bAdded=FALSE;
vd!|k5t[d for(int index=0;index<MAX_KEY;index++){
$4*k=+wS if(hCallWnd[index]==0){
z9[BQ(9t hCallWnd[index]=hWnd;
qECta'b& HotKey[index]=cKey;
z2.Z xL"* HotKeyMask[index]=cMask;
Na2n4x! bAdded=TRUE;
(.54`[2+L KeyCount++;
zWEt< `1M break;
c<j+" }
\3v}:E+3 }
!aub@wH3 return bAdded;
qT+:oMrTSm }
\Z%V)ZRi= //删除热键
%["V "{ z BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
"<I*ViZ {
ISl-W1u} BOOL bRemoved=FALSE;
7BDoF!kCx for(int index=0;index<MAX_KEY;index++){
*/yR_f if(hCallWnd[index]==hWnd){
4w-P%-4 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
{!rpE7P- hCallWnd[index]=NULL;
-R-|[xN HotKey[index]=0;
nPS:T|*G HotKeyMask[index]=0;
6t(I.>- bRemoved=TRUE;
QUU'/e2^c KeyCount--;
&lYe break;
*wetPt)~v_ }
j9Y'HU5" }
&DgJu. }
qCaM]Y return bRemoved;
SvD^'(
x }
t)/:VImY l&1R`g cW nofK(0TF DLL中的钩子函数如下:
51lN,VVD z4yV1 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
c_YP#U {
j?
P=}_Ru BOOL bProcessed=FALSE;
(77EZ07% if(HC_ACTION==nCode)
($ l
t@j {
8~")9w if((lParam&0xc0000000)==0xc0000000){// 有键松开
R7xEE7p switch(wParam)
J|A:C[7 2 {
4BgrG[l) case VK_MENU:
Y"&1jud4xl MaskBits&=~ALTBIT;
t*'U|K4L/ break;
Ei[>%Ah case VK_CONTROL:
8bIwRVA2\ MaskBits&=~CTRLBIT;
+P. }< break;
ayvHS&h case VK_SHIFT:
8
k%!1dyMB MaskBits&=~SHIFTBIT;
%+,7=Wt- break;
&=d0'3k> default: //judge the key and send message
1SYBq,[]) break;
9L^:N)- }
+Y for(int index=0;index<MAX_KEY;index++){
UF ]g6u if(hCallWnd[index]==NULL)
XV>
)[Nd\H continue;
P,@ :?6 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
$rG~0 {
GE{u2<%@ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
56
raZC bProcessed=TRUE;
TQ\\/e: }
<CnTiS# }
,B=;NKo }
sjISVJ? else if((lParam&0xc000ffff)==1){ //有键按下
xEfz AJ5& switch(wParam)
w0FkKJV {
$J]b+Bp case VK_MENU:
X^;LiwQv MaskBits|=ALTBIT;
BCK0fk~ break;
T+y3Ph--^ case VK_CONTROL:
aA5rvP+ MaskBits|=CTRLBIT;
09psqXU@I break;
}L1-2 case VK_SHIFT:
\-?@
&' : MaskBits|=SHIFTBIT;
If*t$f>y4N break;
LgX"Qk&Ca default: //judge the key and send message
^Q'^9M2) break;
A=5A8B1 }
jK{)gO for(int index=0;index<MAX_KEY;index++){
\:/:S"- if(hCallWnd[index]==NULL)
3Y}X7-|)Z continue;
aMaFxEW if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
},G>+ s8h {
;ESuj'*t SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
C=z7Gk= bProcessed=TRUE;
X_0Ta_u?T }
[N-t6Z* }
+%hA6n }
)K0BH q7r if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
(gn)<JJS} for(int index=0;index<MAX_KEY;index++){
fq"<= if(hCallWnd[index]==NULL)
?xbPdG":R continue;
i9FHEu_ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
RI
q9wD}4( SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
xxlYn9ke //lParam的意义可看MSDN中WM_KEYDOWN部分
Ew|VDD(. }
_m+64qG_8' }
] hxE^/8 7 }
(KF=v31_m return CallNextHookEx( hHook, nCode, wParam, lParam );
P,ox))+6 }
E9L)dMZSpj *Q@%<R 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:
^mu?V-4 >lRa},5( BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
HJn BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Z,~EH ,`3kDqS_4 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:
n' \poB? g`}+K U LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
$1h , <$5H {
Y!8Ik(/~i if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
-2dk8]KB] {
<3;Sq~^ //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
Fj`6v"h SaveBmp();
u5,\Kz return FALSE;
w1je|Oil }
Zljj …… //其它处理及默认处理
2^}E!(< }
=vv4;az
X xt%-<%s %f L;7x2& 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
T-:
@p> @@,l0/ 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
1HF=,K+ g?'4G$M 二、编程步骤
$LLy#h?V] >^8=_i ! 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
8}&O7zO? MMMuT^X 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
jORU+g Z>)(yi9+ 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
5s >UM@}) dJZMzn 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
J~6-}z >&|C
E2' 5、 添加代码,编译运行程序。
[,Io!O MVGznf? 三、程序代码
uIG,2u, rI\G&OqpP ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
wgK:^DP #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
6w
d0" #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
h|_E>6d) #if _MSC_VER > 1000
Sc!{
o!9\ #pragma once
qjsS2,wM #endif // _MSC_VER > 1000
;'.[h*u~< #ifndef __AFXWIN_H__
0u]!C"VX #error include 'stdafx.h' before including this file for PCH
j0p'_|)( #endif
6iiH+Nc #include "resource.h" // main symbols
-/>SdR$D7 class CHookApp : public CWinApp
gg>O:np8 {
DA5kox&cU public:
Z\{"/( Hi CHookApp();
Ut;,Z // Overrides
" .9b}} // ClassWizard generated virtual function overrides
nMK,g>wp //{{AFX_VIRTUAL(CHookApp)
,qS-T'[v,( public:
Hoaf3
`n virtual BOOL InitInstance();
):@XMECa virtual int ExitInstance();
o<*H!oyP\ //}}AFX_VIRTUAL
m"{D}(TA //{{AFX_MSG(CHookApp)
CH6^;. // NOTE - the ClassWizard will add and remove member functions here.
fa7I6 i // DO NOT EDIT what you see in these blocks of generated code !
Pd99vq/ //}}AFX_MSG
w&eX)! DECLARE_MESSAGE_MAP()
vjy 59m };
kxJ! #%w LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
d]JiJgfa% BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
%1uY BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
hrpql_9. BOOL InitHotkey();
#S57SD BOOL UnInit();
=Fq"lq % #endif
"t4$%7L] x
\.qzi //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
vJheM*C #include "stdafx.h"
|U*wMYC #include "hook.h"
!2)$lM1@J #include <windowsx.h>
SjT8eH # #ifdef _DEBUG
3d qj:4[f #define new DEBUG_NEW
,k*g`OTW #undef THIS_FILE
l2)) StEm static char THIS_FILE[] = __FILE__;
WUQlAsme #endif
YQyf:xJ #define MAX_KEY 100
~kdxJP" #define CTRLBIT 0x04
2|xNT9RW #define ALTBIT 0x02
rZ0+mS'/G #define SHIFTBIT 0x01
<,%qt_
! #pragma data_seg("shareddata")
W}<'Y@[, HHOOK hHook =NULL;
lg)jc3 UINT nHookCount =0;
1gEeZ\B-& static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
481SDG[b static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
dqU
bJc] static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
?mdgY1 static int KeyCount =0;
a#iJXI static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
'eNcQJh #pragma data_seg()
Zrtyai{8l HINSTANCE hins;
-^m]Tb<u void VerifyWindow();
29(s^#e8A BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
q[l!kC+Eh //{{AFX_MSG_MAP(CHookApp)
A.aUWh // NOTE - the ClassWizard will add and remove mapping macros here.
E2 M|b // DO NOT EDIT what you see in these blocks of generated code!
@Sxb}XI!f //}}AFX_MSG_MAP
i%m]<yElm END_MESSAGE_MAP()
kW"6Gc&HUN ;++CMTza] CHookApp::CHookApp()
5&WYL {
).[Mnt/Ft // TODO: add construction code here,
~J}{'l1{yf // Place all significant initialization in InitInstance
C]ev"Am_)
}
W7k\j&x 1+1Z]!nG#! CHookApp theApp;
_~?N3G LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
C
NDf&dzX8 {
[89qg+z BOOL bProcessed=FALSE;
K3QE>@'] if(HC_ACTION==nCode)
0Q^a*7w`8a {
Zi&qa+F if((lParam&0xc0000000)==0xc0000000){// Key up
Nf.6:= switch(wParam)
'l+).}, {
W\V'o Vt case VK_MENU:
xE$(I<: MaskBits&=~ALTBIT;
cO9aT break;
_`4jzJ* case VK_CONTROL:
2!Ip!IQ: MaskBits&=~CTRLBIT;
pIKQx5; break;
y8=(k}=3 case VK_SHIFT:
vs3px1Xe# MaskBits&=~SHIFTBIT;
Xr54/.{&@ break;
6%/@b`vZ default: //judge the key and send message
l+e L:C! break;
's.%rre% }
AS;EO[Vn for(int index=0;index<MAX_KEY;index++){
2b|$z"97jj if(hCallWnd[index]==NULL)
%d..L-`]ET continue;
>'>onAIL if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
[D[&aA {
Z^AOV:|m SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
q.s 2x0 bProcessed=TRUE;
~f/nq/8 }
cVHv>nd# }
=.q
Zgcg }
$i s|B9B else if((lParam&0xc000ffff)==1){ //Key down
JZQT} switch(wParam)
Gw3H1:yo {
]JQ';%dne case VK_MENU:
2hOr#I$/ MaskBits|=ALTBIT;
H5@N<v5u break;
E^uWlUb{ case VK_CONTROL:
7M~w05tPh MaskBits|=CTRLBIT;
+}IOTw"O` break;
}yde9b?F case VK_SHIFT:
>heFdKq1 MaskBits|=SHIFTBIT;
a<-'4D/ break;
rFY% fo
default: //judge the key and send message
oLJP@J break;
$O}:*.{(W }
+b<q4W for(int index=0;index<MAX_KEY;index++)
kHj|:,'sV {
=yn|.%b if(hCallWnd[index]==NULL)
<I}O_:% continue;
+9S_H( if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
! }u'% {
crV2T SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
iHKWz)0 bProcessed=TRUE;
^j"*-)R }
PCxv_Svf }
iqCZIahf }
dA;f`Bi;Q if(!bProcessed){
c< ke)@ for(int index=0;index<MAX_KEY;index++){
`4Jlf! if(hCallWnd[index]==NULL)
*],]E; continue;
wYTF:Ou^5~ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
7O3 \ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
a78&< }
[I*BEJ;W' }
.Rq|F }
/\=syl return CallNextHookEx( hHook, nCode, wParam, lParam );
L;a>J }
-]1F]d }@-4*5P3 BOOL InitHotkey()
B(<;] {
ekB!d
if(hHook!=NULL){
>P7|-bV nHookCount++;
P4vW.|@ return TRUE;
n@9*>DU }
xngK_n else
$_N<! h*\ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
?:bW@x if(hHook!=NULL)
:OC`X~}Rc nHookCount++;
'%&i#Eb return (hHook!=NULL);
q4)8]Y2 }
V#!ftu#c? BOOL UnInit()
R:7j`gHJ|9 {
%T3L-{s5 if(nHookCount>1){
KF' $D:\ nHookCount--;
YN
Lc ) return TRUE;
'5V2{k$4U }
qq0bIfF\4 BOOL unhooked = UnhookWindowsHookEx(hHook);
52-Gk2dp if(unhooked==TRUE){
c hE~UQ nHookCount=0;
B2UQO4[w hHook=NULL;
pgg4<j_mn }
_h#SP+> return unhooked;
5f&+(Wqw }
8+5-7) vO#4$, BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
!MNo
8dC; {
]ee%=+' BOOL bAdded=FALSE;
gie}k)&M for(int index=0;index<MAX_KEY;index++){
X9^a:7( if(hCallWnd[index]==0){
&M$s@FUY hCallWnd[index]=hWnd;
O9>&E;`5 HotKey[index]=cKey;
(;^VdiJ HotKeyMask[index]=cMask;
)M5:aSRz bAdded=TRUE;
kFPZ$8e KeyCount++;
Xrpzc~( break;
+R}(t{b# }
rSU%!E+|< }
;qT~81 return bAdded;
KD]8n]c }
%a-:f)@ Jq1 Zb BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
}a= &o6= {
/`yb75 BOOL bRemoved=FALSE;
=k]Rze I for(int index=0;index<MAX_KEY;index++){
<5*cc8 if(hCallWnd[index]==hWnd){
eup#.#J if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
]kC/b^~+m hCallWnd[index]=NULL;
^hOnLy2 HotKey[index]=0;
^J0*]k%
HotKeyMask[index]=0;
PfTjC"`, bRemoved=TRUE;
D0(QZrVa KeyCount--;
q|)8VmVV break;
kJP
fL s }
]Y!$HT7\ }
Jt6~L5[_s }
X5kIM\ return bRemoved;
;5tSXgGw7 }
D@T>z; AtNu:U$ void VerifyWindow()
e-Z+)4fH {
[G{{f for(int i=0;i<MAX_KEY;i++){
FilHpnQCt if(hCallWnd
!=NULL){ W.h6g8|wx
if(!IsWindow(hCallWnd)){ CA[-\>J7y
hCallWnd=NULL; !( xeDX
HotKey=0; 0tVZvXgTu
HotKeyMask=0; l_JPkM(mJw
KeyCount--; pNFL;k+p}
} N_TWT&o4
} 9kj71Jp&}
} 4}sfJ0HhX
} wkm;yCF+
SEm3T4dfzf
BOOL CHookApp::InitInstance() ,ZyTYD|7
{ WTi8
AFX_MANAGE_STATE(AfxGetStaticModuleState()); OF^v;4u
hins=AfxGetInstanceHandle(); 9I*zgM!F
InitHotkey(); WlnmW(uahW
return CWinApp::InitInstance(); 3P C'P2
} {<7!=@j
r
(Ab+1b
int CHookApp::ExitInstance() +o)o4l%3
{ E.kGBA;a?
VerifyWindow(); MH|!tkW>:
UnInit(); ES72yh]
return CWinApp::ExitInstance(); `mV&[`NZ
} i,>yIPBU!
(C/2shr 8
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file ON~jt[
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 9J%
~?k
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ @]u nqCO
#if _MSC_VER > 1000 3 A2X1V"
#pragma once G"&9u2 k
#endif // _MSC_VER > 1000 HJT}v/FZ
L~fxVdUz
class CCaptureDlg : public CDialog 0?525^
{
:Rc>=)<7
// Construction E[bJ5o**#
public: k4te[6)
BOOL bTray; .]`L R@qf
BOOL bRegistered; 7a.$tT
BOOL RegisterHotkey(); >h>X/a(=~
UCHAR cKey; !kZ9Ox9^
UCHAR cMask; Rk8>Ak(/
void DeleteIcon(); a[iuE`
void AddIcon(); ur^)bp<