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:
q)PSHr=Z
N6v*X+4JH 一、实现方法
y2PxC. - &zPM#Q 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:
u1|v3/Q- qc3?Aplj #pragma data_seg("shareddata")
W+.?J
60 HHOOK hHook =NULL; //钩子句柄
PPh1y;D UINT nHookCount =0; //挂接的程序数目
!q8A!P4|' static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
kdMB.~(K= static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
{"0n^! static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
!v*#E{r"g= static int KeyCount =0;
wKJK!P static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
9lX[rBZ #pragma data_seg()
V /)3d /x/W>J2 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。
hysxHOL \\/
!I
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:
=|d5V% mK 3]>YBbXvE BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
}'\M}YM cKey,UCHAR cMask)
E8o9ufj3 {
Y3xEFqMU BOOL bAdded=FALSE;
8g/r8u~ for(int index=0;index<MAX_KEY;index++){
R!WeSgKCs if(hCallWnd[index]==0){
cSj(u%9} hCallWnd[index]=hWnd;
k,y#|bf,Y
HotKey[index]=cKey;
">s0B5F7 HotKeyMask[index]=cMask;
kEg~yN bAdded=TRUE;
:0Fwaw9PH" KeyCount++;
lb]k"L%KU7 break;
eh*F/Gu }
^fM=|.? }
5d|+ c< return bAdded;
"H{#ib_c_ }
~'):1}KN] //删除热键
7.C]ZcU BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
&0mhO+g {
*gI9CVfQl BOOL bRemoved=FALSE;
6uFGq)4p@ for(int index=0;index<MAX_KEY;index++){
ND5E`Va5R if(hCallWnd[index]==hWnd){
/PkOF(( if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
lqKwjJtX hCallWnd[index]=NULL;
t;[Q&Jl HotKey[index]=0;
+>v{#A_u HotKeyMask[index]=0;
uMBb=
bRemoved=TRUE;
*1}vn%wvn KeyCount--;
^N~Jm&I break;
:wJ!rn,4 }
SHCVjI6 }
T f^O( }
.gI9jRdKw return bRemoved;
UKSI"/8I }
c:}K(yAdd _j<,qi ,qlFk|A| DLL中的钩子函数如下:
*tT5Zt/&Sr Zn'y"@%t[ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
l1RFn,Tzr {
3*b!]^d:D BOOL bProcessed=FALSE;
5xG/>fn if(HC_ACTION==nCode)
W/;qMP1"- {
J15$P8J if((lParam&0xc0000000)==0xc0000000){// 有键松开
.LNqU#a switch(wParam)
;Y16I#?;Kh {
u"a$/ case VK_MENU:
4U:+iumy2 MaskBits&=~ALTBIT;
)5bdWJ>l break;
?r~](l case VK_CONTROL:
fI0L\^b% MaskBits&=~CTRLBIT;
fmq^AnKd break;
BcoE&I?[m| case VK_SHIFT:
5(OF~mX# MaskBits&=~SHIFTBIT;
RbNRBK!{ break;
gM3gc; default: //judge the key and send message
UJF
}Ye break;
3'2}F%!Mv }
x]U (EX`t$ for(int index=0;index<MAX_KEY;index++){
]t3
NA*mM if(hCallWnd[index]==NULL)
Afa{f}st continue;
X]*W + if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
,@ Cru= {
]R{=| SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
M>k7
'@G bProcessed=TRUE;
jW",'1h<n }
Ic&t_B*i}] }
;h3*MR }
ig/716r| else if((lParam&0xc000ffff)==1){ //有键按下
fhn0^Qc"+ switch(wParam)
7"JU)@ U] {
{UZli[W1 case VK_MENU:
S8vmXlD MaskBits|=ALTBIT;
.^.UJo;4G break;
^! ZjK-$A< case VK_CONTROL:
U w`LWG3T MaskBits|=CTRLBIT;
a\m10Ih: break;
IL:"]`f* case VK_SHIFT:
N<> dg MaskBits|=SHIFTBIT;
6l
vx break;
FvI`S> default: //judge the key and send message
pmW=l/6+V3 break;
\
bT]?.si }
fZ g*@RR for(int index=0;index<MAX_KEY;index++){
Em"X5>;4 if(hCallWnd[index]==NULL)
/?XfVhA:A continue;
x(7K3(#| if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
b);}x1L.T {
xf]4!zE SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
(kuZS4Af bProcessed=TRUE;
-% fDfjP }
tl^[MLQa }
(
L6`_) }
%-'U9e KN if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
.CpF0 for(int index=0;index<MAX_KEY;index++){
7:j #1N[p if(hCallWnd[index]==NULL)
`(a^=e5 continue;
U; q)01 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
'Lw\nO. SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
zm .2L //lParam的意义可看MSDN中WM_KEYDOWN部分
86I* }
Hf-F-~E }
%ej"ZeM }
BmJ?VJ}Y return CallNextHookEx( hHook, nCode, wParam, lParam );
}I`|*6Up }
8say"Qz Q8~pIv 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
q%vUEQLBp N+V-V-PVk BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
,/ : )FV BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
t3XMQ'] zLn#p] 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
nz',Zm}, sq^"bLw LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
M#>GU<4" {
} R/ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
W[m_IY {
dCK-"#T! //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
HY:@=%R SaveBmp();
|#B"j1D,H return FALSE;
7A|jnm }
N.`]D)57 …… //其它处理及默认处理
@&W?e?O ~G }
C(P$,;6 nJya1AH; Z7/dRc
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。
{L eEnh-
k
WtUj 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。
\nyFN bcs!4 二、编程步骤
~z}au"k !T{g& f 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";
Wd}mC<rv1 =KZ4:d5 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
WI,=?~- ?:nZv<
x 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;
Nw2 bn 7. .vaq# 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;
z>:7}=H0 +;Gl>$ 5、 添加代码,编译运行程序。
f)x}_dw% !q/lgpEi 三、程序代码
`[\phv 9F](%/ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
]t3"0 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
d"UW38K{ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
kU/=Du #if _MSC_VER > 1000
JY+[ #pragma once
wjJ1Psnx #endif // _MSC_VER > 1000
)^Pvm #ifndef __AFXWIN_H__
~,68S^nP)H #error include 'stdafx.h' before including this file for PCH
~bTae =FP #endif
_%vqBr* #include "resource.h" // main symbols
gj,J3x4TK/ class CHookApp : public CWinApp
IJY5wP1" {
wPJRp]FA public:
_vV&4> CHookApp();
;-GzGDc~0 // Overrides
'5/}MMT // ClassWizard generated virtual function overrides
\_AEuz3
F //{{AFX_VIRTUAL(CHookApp)
s@LNQ|'kO public:
-==qMrKP virtual BOOL InitInstance();
(iOCzZ6S virtual int ExitInstance();
-QPWi2:k //}}AFX_VIRTUAL
o`mIi //{{AFX_MSG(CHookApp)
cC^C7AAq^ // NOTE - the ClassWizard will add and remove member functions here.
;kW}'&Ug // DO NOT EDIT what you see in these blocks of generated code !
F ssEs!# //}}AFX_MSG
#pQ"+X DECLARE_MESSAGE_MAP()
#6sC&w3 };
*P R_Y=v% LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
.l=*R7~EU BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
Z/= %J3f BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
LDEW00zL BOOL InitHotkey();
`uZv9I" BOOL UnInit();
Rgfhs[Z #endif
}K80G~O2< ^Lmc%y //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
C'czXZtn #include "stdafx.h"
nQ17E{^pR #include "hook.h"
<yI,cM<c #include <windowsx.h>
!LIfeL.4h #ifdef _DEBUG
T#G<?oF #define new DEBUG_NEW
- (_e=3$ #undef THIS_FILE
M:Y*Tb6w static char THIS_FILE[] = __FILE__;
)YMlFzYr #endif
!x$:8R #define MAX_KEY 100
JkDPuTXD #define CTRLBIT 0x04
#;LMtDaL #define ALTBIT 0x02
L\m !8o4 #define SHIFTBIT 0x01
<cv2-?L{ #pragma data_seg("shareddata")
'gZbNg=&[ HHOOK hHook =NULL;
H<Kkj UINT nHookCount =0;
#} ~p^ 0 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
).}k6v[4) static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
|1+(Ny.%k static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
afF+*\xXN static int KeyCount =0;
I\rZk9F static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
6{ +_T #pragma data_seg()
3> \fP#oQ HINSTANCE hins;
c@9Z&2) void VerifyWindow();
xw+<p BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
i=1 }lkq //{{AFX_MSG_MAP(CHookApp)
<L/M`(:=k // NOTE - the ClassWizard will add and remove mapping macros here.
Q5y
q"/=[a // DO NOT EDIT what you see in these blocks of generated code!
~+<xFi //}}AFX_MSG_MAP
dT]L-uRZgy END_MESSAGE_MAP()
PPCTc|G &7($kj CHookApp::CHookApp()
7.$]f71z {
P#[IUXtT // TODO: add construction code here,
'Gl;Ir^ // Place all significant initialization in InitInstance
s`#ntset0 }
4ypRyO E#<7\p> CHookApp theApp;
*9dV/TT~f[ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
}$|%/Y {
c>S"`r BOOL bProcessed=FALSE;
K}PvrcO1 if(HC_ACTION==nCode)
:/@k5#DY {
d<^_w!4X} if((lParam&0xc0000000)==0xc0000000){// Key up
V;iL[ switch(wParam)
gb=80s0 {
{ r6]MS#l1 case VK_MENU:
3`&VRF8 MaskBits&=~ALTBIT;
W>Mse[6`c break;
WYwzo V- case VK_CONTROL:
7.Ml9{M/i MaskBits&=~CTRLBIT;
U_x0KIm break;
S9G8aea/ case VK_SHIFT:
v#<\:|XAg MaskBits&=~SHIFTBIT;
E\R raPkQT break;
=MTj4VXh" default: //judge the key and send message
<#xrrRhm} break;
R=\v3m }
]`zjRRd for(int index=0;index<MAX_KEY;index++){
b
A)b`1lI if(hCallWnd[index]==NULL)
+"YTCzv;t continue;
8?e if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
|`w$|pm= {
09R,'QJ| SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
=cdh'"XN bProcessed=TRUE;
%<aImR] }
x1Nme%%& }
v[R_S }
$Hp.{jw else if((lParam&0xc000ffff)==1){ //Key down
2;~KL-h0TK switch(wParam)
k(zs>kiP {
968Ac}OA case VK_MENU:
4)c+t"h MaskBits|=ALTBIT;
IIq"e~"Vs break;
')C|`(hs case VK_CONTROL:
,3:QB_ MaskBits|=CTRLBIT;
cJP'ShnCh break;
`aO.=:O_ case VK_SHIFT:
>65
TkAp MaskBits|=SHIFTBIT;
X$BXT break;
`Uzs+k-] default: //judge the key and send message
nHSTeFI? break;
uDILjOT }
T|;^.TZ for(int index=0;index<MAX_KEY;index++)
McEmd.S<n {
}l.KpdRT2 if(hCallWnd[index]==NULL)
LkaG8#m1R continue;
M$,Jg5Dc if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
)*!1bgXQ {
NmjzDN SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
;xSRwSNDi( bProcessed=TRUE;
>4Iv[ D1 }
j: <t }
q^u1z|'Z }
Lb!r(o>8Cb if(!bProcessed){
dO+kPC for(int index=0;index<MAX_KEY;index++){
hgj CXl if(hCallWnd[index]==NULL)
HKpD2M continue;
PdR >;$1 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Qqp)@uM^ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
PT mf }
6yN"
l
Q7 }
%h0D)6j
}
Am#m>^!qb return CallNextHookEx( hHook, nCode, wParam, lParam );
BpH|/7 }
e:qo_eSC^- '#H&:Htm;L BOOL InitHotkey()
{b(rm,% {
?LM:RADCm if(hHook!=NULL){
h>dxBN nHookCount++;
ll_}& a0G return TRUE;
fb/qoZ }
aJI>FTdK else
l x7Kw% hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
h:f;mn?x if(hHook!=NULL)
3KtAK9PT nHookCount++;
pNuqT* return (hHook!=NULL);
b<\$d4Qy }
{&uT3*V1 BOOL UnInit()
9 >%+bA( {
\ZqK\= if(nHookCount>1){
w.tW=z5 nHookCount--;
>
9o{(j return TRUE;
j?( c}!} }
?J<T BOOL unhooked = UnhookWindowsHookEx(hHook);
:H{Bb{B% if(unhooked==TRUE){
i9KTX%s5^ nHookCount=0;
Ga.0Io&}C hHook=NULL;
<p09oZ{6 }
[qiOd! return unhooked;
INOH{`}Ew }
N9pwWg&<+ &1=g A.ZR BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
t{~@I {
Hv3W{| BOOL bAdded=FALSE;
(e(Rr4 for(int index=0;index<MAX_KEY;index++){
)R~a;?T_c0 if(hCallWnd[index]==0){
2@fa
rx: hCallWnd[index]=hWnd;
+1x)z~q= HotKey[index]=cKey;
zFOL(s.h|0 HotKeyMask[index]=cMask;
jSB'>m] bAdded=TRUE;
1ADv?+j)A/ KeyCount++;
^L ]B5,}- break;
N^lAG"Jao[ }
wajZqC2yg }
4x(F&0 return bAdded;
bhn5Lz$z }
o,J^ e_ {(%~i37 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
!\ZcOk2 {
( :iPm< BOOL bRemoved=FALSE;
J=@xAVBc for(int index=0;index<MAX_KEY;index++){
8|6~o.B.G if(hCallWnd[index]==hWnd){
r( M[8@Nz if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
rfX=*mjt hCallWnd[index]=NULL;
e^=NL>V6p HotKey[index]=0;
g*F~8+]Y HotKeyMask[index]=0;
Y!M~#oqio bRemoved=TRUE;
Mo_$b8i KeyCount--;
q4+Yv2e
<r break;
u7[pLtOwN }
ac|/Y$\w }
.wD>Gs{sH[ }
^Wm*-4 return bRemoved;
N2T&,&,t }
YIO.yN"0 AxEc^Cof void VerifyWindow()
rEmwKZF' {
Si]X
rub for(int i=0;i<MAX_KEY;i++){
gn^!"MN+g if(hCallWnd
!=NULL){ `4skwvS=
if(!IsWindow(hCallWnd)){ p=vV4 C:
hCallWnd=NULL; 'aZASPn[
HotKey=0; S_$nCyaH2
HotKeyMask=0; eKyqU9
KeyCount--; SetX#e?q~
} p.5e:
i^LJ
} nn'Af,ko/
} ~{$L9;x
} .+HcA x{/2
a>w~FUm*
BOOL CHookApp::InitInstance() I )5<DZB9
{ 6P^hN%0
AFX_MANAGE_STATE(AfxGetStaticModuleState()); ~pRs-
hins=AfxGetInstanceHandle(); <