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:
b$N&sZ
;`
!j~ 一、实现方法
]::g-&%Um N _|tw 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
hw0u?++ kB=\a( #pragma data_seg("shareddata")
p]x9hZ HHOOK hHook =NULL; //钩子句柄
5^C.}/#>F UINT nHookCount =0; //挂接的程序数目
Yl"l|2
: static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
cc:,,T/i static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
wg=-&- static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
b|nh4g static int KeyCount =0;
Mcqym8,q|3 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
*V?p&/>MT #pragma data_seg()
2Z7r ZjXW DgKe!w$ 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。
M1J77LfS8 Kq;s${ |G 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:
&'oZ]}^0 :7)lg iM2 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
L[O.]2 cKey,UCHAR cMask)
q1,jDJglZ {
$kd9^lj#[ BOOL bAdded=FALSE;
`l+
pk% for(int index=0;index<MAX_KEY;index++){
[6f(3|" if(hCallWnd[index]==0){
P:fcbfH+ hCallWnd[index]=hWnd;
~'#,*kA:6 HotKey[index]=cKey;
rixt_}aE HotKeyMask[index]=cMask;
`R,g_{Mj bAdded=TRUE;
!b8.XGo KeyCount++;
,O`~ D~$ break;
S94S[j0D }
MhZ\]CAs9 }
N~+ e\K6 return bAdded;
wOF";0EN }
dQJ)0!B //删除热键
]B3f$;W BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Uq^-km#a {
9_xJT^10 BOOL bRemoved=FALSE;
}N0v_Nas;v for(int index=0;index<MAX_KEY;index++){
?C(3T KH if(hCallWnd[index]==hWnd){
+AYB0`X) if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
4}Dfi5:
hCallWnd[index]=NULL;
<CGABlZ HotKey[index]=0;
Xhp={p; HotKeyMask[index]=0;
GEtzLaq< bRemoved=TRUE;
%JPBD]&M KeyCount--;
' ?uwUBi break;
_:~I(c6 }
`%Dz 8Z }
~TYpq;rq }
GGez!?E% return bRemoved;
\^x`GsVy }
bE6bx6=u ^0HgE;4 5F$~ZDu DLL中的钩子函数如下:
HUalD3
\ 'g:.&4x_w LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
0bl 8J5Ar5 {
D.*o^{w| BOOL bProcessed=FALSE;
k nljc^ if(HC_ACTION==nCode)
u{5+hZ {
xl ,(=L] if((lParam&0xc0000000)==0xc0000000){// 有键松开
%gEgpJd switch(wParam)
";;Nc>-Y {
v@QfxV2 case VK_MENU:
HcCT=x7: MaskBits&=~ALTBIT;
Hv-f :P O break;
Dbw{E:pq case VK_CONTROL:
D\^\_r): MaskBits&=~CTRLBIT;
`rb}"V+ break;
fVz0H1\J& case VK_SHIFT:
8c%_R23 MaskBits&=~SHIFTBIT;
~_a$5Y break;
cf,^7,-`" default: //judge the key and send message
A5go)~x\ break;
'+v[z=.8] }
98XlcI# for(int index=0;index<MAX_KEY;index++){
IsiBn(1Z if(hCallWnd[index]==NULL)
kK/([! continue;
dO4Jf9) if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
p(.z#o# {
I R~szUY6 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
QC6:ZxP bProcessed=TRUE;
-8Hv3J'= }
Yht |^ =a }
:gTtWJ04] }
`X%Qt~ else if((lParam&0xc000ffff)==1){ //有键按下
@t2S"s$m switch(wParam)
_K3;$2d|R {
GTke<R case VK_MENU:
#=,c8"O MaskBits|=ALTBIT;
3jjV
bm break;
y'C case VK_CONTROL:
DLPg0>;jl MaskBits|=CTRLBIT;
D[dI_|59a break;
B7(bNr case VK_SHIFT:
=@!s[ MaskBits|=SHIFTBIT;
H1r8n$h break;
+}iuTqu5 default: //judge the key and send message
;s?,QvE{r# break;
tHV+#3h }
f&!{o= for(int index=0;index<MAX_KEY;index++){
|:pBk: if(hCallWnd[index]==NULL)
<&l@ ):a continue;
Y_/w}HB if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
uZa)N-=b2 {
ht2J, 1t SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
v+C%t!dx bProcessed=TRUE;
0t%`jY~% }
upiYo(sN. }
3;F up4!4} }
` >[Offhd if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
cUr5x8<W). for(int index=0;index<MAX_KEY;index++){
ZMGC@4^F if(hCallWnd[index]==NULL)
gWfMUl continue;
pkc*toW if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
g`dAj4B SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
W1ql[DqE{ //lParam的意义可看MSDN中WM_KEYDOWN部分
10CRgrZ }
H18pVh }
t**MthnW }
5%"sv+iO return CallNextHookEx( hHook, nCode, wParam, lParam );
m8Rt>DY }
Ge1"+:tbJ ~cSE 9ul 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:
)i<Qg.@MX >[S\NAE> BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
$:D\yZ, BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
> ,x``- lJt?0;gn 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:
WmuYHE U 4VhKV JX LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
kOQ!]-; {
(Q"~bP{F if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
>cH}sNHy {
7
lu_E.Bv //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
4wPP/` SaveBmp();
{J-Ojw|Y b return FALSE;
H^+Znmo }
e17]{6y …… //其它处理及默认处理
NmTo/5s }
ZQAiuea yT[)V[} ,6aF~p;wI| 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。
[y"Yi PK yC[Q-P *rG 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。
d
9]zB-A 9yp'-RKjw 二、编程步骤
4P?@NJp bJ]blnH 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";
B1TWOl?d{ $V;0z~&!' 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
_Zus4&' P?J\pJ1|7 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
')ZZ)&U>z =m6<H 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
aa}U87]k M:oZk&cs 5、 添加代码,编译运行程序。
f=-R<l VYkUUp 三、程序代码
@_
Tq>tOr& =l>=]O~h ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
VyWzb #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
n$<n
Yr`X #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
6foiN W+ #if _MSC_VER > 1000
{Gw{W&< #pragma once
t(UdV #endif // _MSC_VER > 1000
04:QEC"9mj #ifndef __AFXWIN_H__
uG(XbDZZ1W #error include 'stdafx.h' before including this file for PCH
EPU3Jban
#endif
P?Kg7m W #include "resource.h" // main symbols
XO}SPf- class CHookApp : public CWinApp
!UHX?<3r {
yeA]j[ # public:
eg"A?S CHookApp();
[X ]XH // Overrides
KxDfPd+j[ // ClassWizard generated virtual function overrides
'?T<o //{{AFX_VIRTUAL(CHookApp)
g#o9[su public:
X?Or. virtual BOOL InitInstance();
.\8LL,zT virtual int ExitInstance();
1V-si bE //}}AFX_VIRTUAL
eE@7AM //{{AFX_MSG(CHookApp)
j|LO g // NOTE - the ClassWizard will add and remove member functions here.
%$=2tfR // DO NOT EDIT what you see in these blocks of generated code !
fni7HBV? //}}AFX_MSG
szp.\CMz DECLARE_MESSAGE_MAP()
sU/vXweky" };
NMESGNa)z LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
9]:F!d/ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
eQ<GNvm BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
.M0pb^M BOOL InitHotkey();
bSa]={}L( BOOL UnInit();
<t dsUh:?& #endif
l0eh}d k=9k4l //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
2yVQqwQm #include "stdafx.h"
ynJ)6n7a #include "hook.h"
9[h8Dy #include <windowsx.h>
6u xF< #ifdef _DEBUG
xW58B #define new DEBUG_NEW
SD jJ?K #undef THIS_FILE
omI"xx static char THIS_FILE[] = __FILE__;
@>+`1C #endif
5>h/LE]" #define MAX_KEY 100
Qe`Nb4xf #define CTRLBIT 0x04
YMj iJTl #define ALTBIT 0x02
O$X^Ea7~ #define SHIFTBIT 0x01
=]o2{d #pragma data_seg("shareddata")
~Xc1y!"9* HHOOK hHook =NULL;
j|@8VxZ UINT nHookCount =0;
6O" y static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
: :928y static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
(&M,rW~Qxs static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
GN+!o($ static int KeyCount =0;
/!U(/ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
8:K_S a% #pragma data_seg()
'
?a d HINSTANCE hins;
\vE-;, void VerifyWindow();
v!AfIcEV BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
Yn>FSq^Wp- //{{AFX_MSG_MAP(CHookApp)
u]P9ip"Z // NOTE - the ClassWizard will add and remove mapping macros here.
1jd.tup // DO NOT EDIT what you see in these blocks of generated code!
%yK- Q,'O //}}AFX_MSG_MAP
\W|ymV_Ki END_MESSAGE_MAP()
\/9 O5`u*V .Dy2O*` CHookApp::CHookApp()
r9p ((ir {
I_|W'%N] // TODO: add construction code here,
&_' evZ8 // Place all significant initialization in InitInstance
V!s#xXD } }
fC/P W`4Ae F(w<YU%6 CHookApp theApp;
CKX3t:HP0 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
d"S\j@ {
1*:BOoYx BOOL bProcessed=FALSE;
SVPksr if(HC_ACTION==nCode)
7wHd*{^9N {
h~q5GhY!9 if((lParam&0xc0000000)==0xc0000000){// Key up
(]-RL
A> switch(wParam)
ES)_X:\X?V {
eWXR #g!%> case VK_MENU:
Wr+1e1[ MaskBits&=~ALTBIT;
RtEx
WTc break;
Q1!+wC case VK_CONTROL:
L;=LAQ6[ MaskBits&=~CTRLBIT;
=FQH5iSd break;
L }R-| case VK_SHIFT:
10tTV3`IM MaskBits&=~SHIFTBIT;
a[=ub256S break;
Wr8}=\/ default: //judge the key and send message
KK4rVb:- break;
[B j\h7G }
VRg
y for(int index=0;index<MAX_KEY;index++){
$<L@B|}F) if(hCallWnd[index]==NULL)
hJ?PV@xy continue;
XE#$|Z if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
ycf)*0k {
)U{\c2b SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
hLT?aQLx bProcessed=TRUE;
H%{k.#O }
:bkmm,%O }
-X-sykDm }
J^zB5W,) else if((lParam&0xc000ffff)==1){ //Key down
N w/it*f switch(wParam)
Su<>UsdUC {
VdGpreRPC case VK_MENU:
[4+I1UR` MaskBits|=ALTBIT;
#Vy:6O break;
HT6$|j case VK_CONTROL:
p9&gKIO_m MaskBits|=CTRLBIT;
[@@EE>
y break;
<Vh}d/ case VK_SHIFT:
yoM^6o^,D MaskBits|=SHIFTBIT;
M3eFG@, break;
T-x}o default: //judge the key and send message
Kp19dp}'b break;
#P
{|7}jk
}
;,xM* for(int index=0;index<MAX_KEY;index++)
s\Ln {
/Eu|Jg=I if(hCallWnd[index]==NULL)
>uFFTik continue;
whFJ] if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
4ZkaH(a1 {
Xm<|m# SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
+]Ev bProcessed=TRUE;
DeI3(o7 }
u[nLrEnD }
^OK;swDW }
i;\n\p1 if(!bProcessed){
orAr3`AR3 for(int index=0;index<MAX_KEY;index++){
c7nbHJi if(hCallWnd[index]==NULL)
LtV,djk continue;
"d2JNFIHb if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
u,]qrlx{ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
FJBB@<>: }
csV3mzP }
%zO>]f& }
[rz5tfMp return CallNextHookEx( hHook, nCode, wParam, lParam );
YUTI)&y }
+K,T^<F; 7tne/Yz BOOL InitHotkey()
w"L]?# {
#X0Xc2}{f if(hHook!=NULL){
_/YM@%d nHookCount++;
xl9S=^`= return TRUE;
tjQ6[` }
dV
/Es else
ndw&F'.r hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
,:0!+1 if(hHook!=NULL)
((M>To_l nHookCount++;
fh`}~ aQ return (hHook!=NULL);
z
G`|) }
V`G^Jyj BOOL UnInit()
'=J|IN7WT {
P1|3%#c if(nHookCount>1){
9<o*aFgCa nHookCount--;
V7B%o:FZo return TRUE;
h~O^~"jc }
"*:?m{w5 BOOL unhooked = UnhookWindowsHookEx(hHook);
.vd*~U" if(unhooked==TRUE){
%AA-G nHookCount=0;
5Ha(i [d hHook=NULL;
V7D<'! }
*;Za)) return unhooked;
uUe#+[bD }
Ao@WTs9 _|#P~Ft
BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
m= %KaRI {
+o35${ BOOL bAdded=FALSE;
!Z0S@]C for(int index=0;index<MAX_KEY;index++){
)S}.QrG if(hCallWnd[index]==0){
Q]OR0-6<. hCallWnd[index]=hWnd;
WkV0,_(P HotKey[index]=cKey;
ft~QVe! HotKeyMask[index]=cMask;
'r1X6?dJ bAdded=TRUE;
:_Iz(
2hV KeyCount++;
u/xP$ break;
[WXcp1p
}
<RcB: h }
-h=wLYl@0i return bAdded;
'@5x=> }
5?|y%YH;R\ %vUUx+ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
8"rK {
-![{Zb@ BOOL bRemoved=FALSE;
IsjN
xBM for(int index=0;index<MAX_KEY;index++){
rl-#Ez if(hCallWnd[index]==hWnd){
cfy9wD if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
]hRs -x hCallWnd[index]=NULL;
L@J$kqWY HotKey[index]=0;
UJjtDV3@_g HotKeyMask[index]=0;
M XuHA? bRemoved=TRUE;
ONUa7 KeyCount--;
O9RnS\ break;
4 b}'W} }
-VP_Aw$ }
e0IGx]5i }
`%~f5< return bRemoved;
TQOJN }
@6-3D/= Jg$ NYs.xZ void VerifyWindow()
&SPIu, {
-6^Ee?" for(int i=0;i<MAX_KEY;i++){
0*j\i@ if(hCallWnd
!=NULL){ g_eR&kuh
if(!IsWindow(hCallWnd)){ &E@mCQ1
hCallWnd=NULL; .~a8\6t
HotKey=0; T0 cm+|S
HotKeyMask=0; }a%Wu 7D
KeyCount--; '1zC|:,
} ca[*#xiJ
} nO;ox*Bk+8
} 7,Q7`}gBf
} ]SN5&S
;a[3RqmKW
BOOL CHookApp::InitInstance() e.(RhajB
{ a;(,$q3M
AFX_MANAGE_STATE(AfxGetStaticModuleState()); w)h"?'m~
hins=AfxGetInstanceHandle(); Vkqfs4 t
InitHotkey(); \?^ EFA+;
return CWinApp::InitInstance(); I,V'J|=j
} m-qOyt
i6i;{\tc
int CHookApp::ExitInstance() r%LG>c`^
{ z[JM ]Wy
VerifyWindow(); YL[y3&K
UnInit(); o+\?E.%%g
return CWinApp::ExitInstance(); syb$%
} 5!6}g<z&L
UYpln[S
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file luz,z(
v
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 7K!n'dAi6
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ _b
&Aa%
#if _MSC_VER > 1000 @d|]BqQ4jh
#pragma once Nt[&rO3s
#endif // _MSC_VER > 1000 + Cq&~<B
5=!aq\
5
class CCaptureDlg : public CDialog !V/p.O
{ [U7r>&