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:
:NE/Ddgc'
rQr!R$t/[ 一、实现方法
G5Yk bw# /XbW<dfl 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:
sn{tra ^sClz*%? #pragma data_seg("shareddata")
)(TAT< HHOOK hHook =NULL; //钩子句柄
2*1ft>Uty UINT nHookCount =0; //挂接的程序数目
[po "To static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
+B"0{>n}F static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
@Rq}nq=k static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
|"Z{I3Umg static int KeyCount =0;
s\3q!A?S3 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
L:R<e#kgS #pragma data_seg()
[*4fwk^ @S3f:s0~D 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。
+!yXTC 6QZp@ 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:
;rHO&(h- 0XU}B\'< BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
T@YGB]*Y cKey,UCHAR cMask)
;_+uSalt {
Q8nId<\( BOOL bAdded=FALSE;
ELD!{bMT for(int index=0;index<MAX_KEY;index++){
5V5w:U>_z if(hCallWnd[index]==0){
'Jj=RAV` hCallWnd[index]=hWnd;
j*R,m1e8 HotKey[index]=cKey;
N4!<Xj HotKeyMask[index]=cMask;
QP(BZJC bAdded=TRUE;
I;MD>%[W, KeyCount++;
q|(W-h+ break;
I4c!m_sr }
/X*oS&-M }
sen=0SB/ return bAdded;
A\sI<WrH }
+OHGn;C //删除热键
l*=aMjd? BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
L
3XB"A# {
T)iW`vZg8 BOOL bRemoved=FALSE;
CA s>AXbs for(int index=0;index<MAX_KEY;index++){
b[ w;i]2 if(hCallWnd[index]==hWnd){
zJN7<sv if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
gAbD7SE hCallWnd[index]=NULL;
5Fw - d HotKey[index]=0;
obH;g* HotKeyMask[index]=0;
$jzFc!rs bRemoved=TRUE;
nv/[I,nw KeyCount--;
_lxco=qd=% break;
P 7D!6q }
zGo|JF }
gFN9jM }
r ,(Mu return bRemoved;
YTaLjITG }
L,_.$1d gE7L L=x !nf-}ze{ DLL中的钩子函数如下:
/bRg?Q qSU|= LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
:l u5Uu~ {
}j{!-& BOOL bProcessed=FALSE;
6;b9swmh if(HC_ACTION==nCode)
2 -+f1, {
ps|)cW3` if((lParam&0xc0000000)==0xc0000000){// 有键松开
IVxWxM*N< switch(wParam)
2tQ`/!m>v$ {
JK_OZ case VK_MENU:
}?8uH/+ZA MaskBits&=~ALTBIT;
Yl cbW0'c break;
LRb,VD:/Y case VK_CONTROL:
)X+mV MaskBits&=~CTRLBIT;
>!6JKL~= break;
^%T7. 1'x case VK_SHIFT:
Qx3eLfm MaskBits&=~SHIFTBIT;
Ukz;0q break;
6=GZLpv default: //judge the key and send message
$14:(< break;
{tP%epQ }
p<Z3tD;Z for(int index=0;index<MAX_KEY;index++){
},$0&/>ft if(hCallWnd[index]==NULL)
g=@_Z" continue;
|,C#:"z; if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
/! ajsn {
~`MS~,, SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
iP@6hG`: bProcessed=TRUE;
wucV_p.E }
YvL?j }
tA.`k;LT }
3Hi+Z}8 else if((lParam&0xc000ffff)==1){ //有键按下
tl yJmdl switch(wParam)
l:|D,q {
k`KGB case VK_MENU:
}ET,ysa MaskBits|=ALTBIT;
+|cI:|H> break;
}
l667N case VK_CONTROL:
KxGX\
MaskBits|=CTRLBIT;
t0&@h\K break;
koG{
|elgB case VK_SHIFT:
p&p.Q^"ok MaskBits|=SHIFTBIT;
R6;Phdh<> break;
t:~t@4j} default: //judge the key and send message
.>g1$rj break;
jR ~DToQ }
sfT+i;p for(int index=0;index<MAX_KEY;index++){
/hW d/H] if(hCallWnd[index]==NULL)
kK>X rj6 continue;
q-$`k if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
`bI)<B {
&Nl2sey SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
rM}0%J' bProcessed=TRUE;
o?Nu:&yE }
pcS+o }
_mE^rT }
\kIMDg3} if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
LHCsk{3 for(int index=0;index<MAX_KEY;index++){
:t$aN|>y if(hCallWnd[index]==NULL)
VaZn{z continue;
*V^ #ga#A if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
]
f>]n SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
q z&+=d@ //lParam的意义可看MSDN中WM_KEYDOWN部分
r{Rg920 }
&a)eJF]:! }
-cF'2Sfr }
7k%T<;V return CallNextHookEx( hHook, nCode, wParam, lParam );
p0p4Xh1e }
*4Fr&^M\ e&q?}Ho 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:
\uOdALZ ^)yTBn, BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
's
x\P[a BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
2(!fg4#+ =1;= 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:
5r{;CKKz ,1{Ep` LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
.0HZNWRtb {
F51.N{' if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
`\Ku]6J]5 {
#.B"q:CW*P //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
I8Vb-YeS SaveBmp();
`\|ssC8u return FALSE;
a?5[k}\ }
oS,I~}\kQ …… //其它处理及默认处理
V_n<?9^4 }
)QiQn=Ce ?/*~;fM +?D6T!) 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。
5
LP?Ij 8euZTfK9e 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。
oT95^y\9 HG>j5 二、编程步骤
>?W[PQ5 yx { >{B`e`$ 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";
7\
SUr9[ /nx'Z0&+X 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
M&Y .; + bhym+ 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;
?ne_m:J[ f2)XP$: 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;
7YWNd^FI
V xom<P+M!| 5、 添加代码,编译运行程序。
$.St ej1 {[Q0qi = 三、程序代码
YMpf+kN 1{"llD ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
:q##fG'm/ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
=8G&3 R #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
']6VB,c` #if _MSC_VER > 1000
5m$2Ku #pragma once
]Z<_ "F #endif // _MSC_VER > 1000
H/F+X?t$0 #ifndef __AFXWIN_H__
^{@![' #error include 'stdafx.h' before including this file for PCH
e59dVFug.U #endif
dpZ;l 9 #include "resource.h" // main symbols
$9
p!Y} class CHookApp : public CWinApp
E|"=.
T {
Z-=YM P ]Q public:
n_K~vD CHookApp();
}$su4A@0 // Overrides
JeH;v0 // ClassWizard generated virtual function overrides
[^H"FA[ //{{AFX_VIRTUAL(CHookApp)
FXKF\1`(H public:
OIb virtual BOOL InitInstance();
XdgUqQb} virtual int ExitInstance();
Tq<2`*Qs //}}AFX_VIRTUAL
dmrps+L //{{AFX_MSG(CHookApp)
@!=\R^#p // NOTE - the ClassWizard will add and remove member functions here.
=x#FbvV // DO NOT EDIT what you see in these blocks of generated code !
-!qu"A: //}}AFX_MSG
vP!GJX&n5 DECLARE_MESSAGE_MAP()
<{(/E0~V/< };
}SyxPXs LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
<M?: BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
tEd.'D8 s BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
5,"l0nrk BOOL InitHotkey();
z:Sigo_z[ BOOL UnInit();
mbl]>JsQD #endif
xk~IN%\ 84zTCX //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
%bXx!x8( #include "stdafx.h"
]6Ug>>x5 #include "hook.h"
zkM"cb13q/ #include <windowsx.h>
F^aR+m #ifdef _DEBUG
4] > ]-b #define new DEBUG_NEW
`WEZ"5n #undef THIS_FILE
*TW=/+j static char THIS_FILE[] = __FILE__;
9D\4n #endif
Uh}seB#mJj #define MAX_KEY 100
;Z[]{SQ #define CTRLBIT 0x04
V5}nOGV9 #define ALTBIT 0x02
V2Q$g^X' #define SHIFTBIT 0x01
SD\=
m/W #pragma data_seg("shareddata")
/{2*WI; HHOOK hHook =NULL;
}n,Zl>T9 UINT nHookCount =0;
Myat{OF static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
qMBR *f static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
zZ-wG static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
f67NWFX static int KeyCount =0;
wbyE;W static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
;#G oGb4AM #pragma data_seg()
S&C1 TC HINSTANCE hins;
_:n b&B void VerifyWindow();
Gnm4gF!BI BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
FxG7Pk+= //{{AFX_MSG_MAP(CHookApp)
Bc-yxjsw // NOTE - the ClassWizard will add and remove mapping macros here.
B-.v0R`5 // DO NOT EDIT what you see in these blocks of generated code!
?eV(1Fr@ //}}AFX_MSG_MAP
$5`!Z%>/ END_MESSAGE_MAP()
5y2?
f 8qi+IGRg CHookApp::CHookApp()
Vpfp}pL {
_?7#MWe& // TODO: add construction code here,
9ILIEm: // Place all significant initialization in InitInstance
ER2GjZa\z }
*MNHT`Y^o M_0zC1 CHookApp theApp;
M/PFPJ >` LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
c9' ' {
O/%< }3Sq BOOL bProcessed=FALSE;
PeX1wK%f if(HC_ACTION==nCode)
>4m'tZ8 {
xieP "6 if((lParam&0xc0000000)==0xc0000000){// Key up
sH,kW|D switch(wParam)
5/[H+O1; {
u/b7Z`yX} case VK_MENU:
h)lPi MaskBits&=~ALTBIT;
b/$km?R break;
:vx$vZb case VK_CONTROL:
6Q4X6U:WB MaskBits&=~CTRLBIT;
IJOvnZ("A break;
rn@`yTw^ case VK_SHIFT:
uD_v! MaskBits&=~SHIFTBIT;
X#xFFDzN break;
=M 6[URZ default: //judge the key and send message
r#PMy$7L break;
_eSdnHWx }
K)7zKEp`cj for(int index=0;index<MAX_KEY;index++){
Bsf7mcXz7z if(hCallWnd[index]==NULL)
-!RtH |P continue;
%1
KbS
[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
hjZ}C+=O {
JuRH>` SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
%Kh4m7 bProcessed=TRUE;
%U7.7dSOI; }
-b&{+= ^c }
v7 }
4 PLk else if((lParam&0xc000ffff)==1){ //Key down
,:Jus switch(wParam)
%\O#&=$E {
tary6K9K+ case VK_MENU:
,y`CRlr: MaskBits|=ALTBIT;
h<<>3 A break;
m .IU ;cR case VK_CONTROL:
_i_Q?w` MaskBits|=CTRLBIT;
}TRAw#h break;
i=a-<A5x case VK_SHIFT:
iO/XhSD MaskBits|=SHIFTBIT;
Eh</? Qv\ break;
?,P3)&3g default: //judge the key and send message
8VG!TpX/B break;
-W{DxN1 }
&K_)#v`| for(int index=0;index<MAX_KEY;index++)
Tl]e%A`| {
$yDWu"R8 if(hCallWnd[index]==NULL)
vgt]:$ continue;
m ~#! if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
NvE}eA# {
UEs7''6RM SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
%t=kdc0=_ bProcessed=TRUE;
+=Jir1SLV }
]=rht9)," }
x_=n-lAF }
U/ V if(!bProcessed){
A61^[Y,dX_ for(int index=0;index<MAX_KEY;index++){
'oNO-)p\#! if(hCallWnd[index]==NULL)
yw[ # continue;
mOpTzg@ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
r;9 r!$d SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
#
?1Sm/5k` }
wHZW ` }
<H3ezv1M }
# ,uya2!) return CallNextHookEx( hHook, nCode, wParam, lParam );
|yyO q }
%+ 7p lM @J{m@ji{ BOOL InitHotkey()
G CRz<)1 {
m^' uipa\ if(hHook!=NULL){
65z" nHookCount++;
0.$hn return TRUE;
AL/?,%F }
[=O/1T else
{ pu85'DV hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
qbrp P(. if(hHook!=NULL)
Z UKf`m[ nHookCount++;
.)1_Ew return (hHook!=NULL);
A,su;Qh }
]&Z))H BOOL UnInit()
64Lx-avf {
_0+0#! J! if(nHookCount>1){
]v[|B nHookCount--;
b[z]CP return TRUE;
jVLA CWH }
2._X|~0a BOOL unhooked = UnhookWindowsHookEx(hHook);
umz;F if(unhooked==TRUE){
01!s"wjf nHookCount=0;
gVeEdo`$< hHook=NULL;
%h1N3\y9i( }
I%|>2}-_U return unhooked;
pEECHk }
Y_`- 9'& '|;X0fD BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Bq/:Nd[y {
Cg*H.f%Mr BOOL bAdded=FALSE;
Pxn,Qw* for(int index=0;index<MAX_KEY;index++){
sNun+xsf^ if(hCallWnd[index]==0){
IwGqf.!.> hCallWnd[index]=hWnd;
!4] 9!<.k HotKey[index]=cKey;
.q+0pj HotKeyMask[index]=cMask;
l
& Dxg bAdded=TRUE;
E.1J2Ne KeyCount++;
?UM*Xah break;
f#ri'&}c
: }
lKk/p^: }
KfF!{g f return bAdded;
vb9OonE2 }
Wg`R_>qQSm 2Sm}On BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Z{'i F {
r1RG TEkD BOOL bRemoved=FALSE;
UGK*G y for(int index=0;index<MAX_KEY;index++){
1+?N#Fh if(hCallWnd[index]==hWnd){
f6$b
s+oP if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
iQ{G(^sZN hCallWnd[index]=NULL;
g^zs,4pPU< HotKey[index]=0;
.k,YlFvj HotKeyMask[index]=0;
@k&qb!Qah bRemoved=TRUE;
4Qn$9D+? KeyCount--;
\W,I?Kx$ break;
Q_l'o3 }
Sna4wkbS }
;#Q%j%J }
Jmx Ko+- return bRemoved;
6;b~Ht }
L5MzLE&~ F-6c_! void VerifyWindow()
+>JjvYx}\ {
P;4w*((} ~ for(int i=0;i<MAX_KEY;i++){
HV<Lf
6gE if(hCallWnd
!=NULL){ $ImrOf^qt
if(!IsWindow(hCallWnd)){ o.I6ulY8
hCallWnd=NULL; Yup3^E
w&
HotKey=0; v0L\0&+
HotKeyMask=0; 5h; +Ky!I
KeyCount--; 7g3>jh
} ,a#EW+" Z
} 4>J
} AlJ} >u
} Q|@4bz i)
ElUEteZ
BOOL CHookApp::InitInstance() 0Lb4'25.
{ <F04GO\
AFX_MANAGE_STATE(AfxGetStaticModuleState()); S{3nM<
hins=AfxGetInstanceHandle(); NFv>B>
InitHotkey(); bJD;>"*
return CWinApp::InitInstance(); V*~Zs'L'E
} c [5KG}
*z7dl5xJ
int CHookApp::ExitInstance() 0iJue&
{ j1(D]Z=\
VerifyWindow(); 2PG [7u^
UnInit(); xMBaVlEN
return CWinApp::ExitInstance(); <