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:
f6m^pbQFl
2/;KZ+U& 一、实现方法
P017y&X r2Q"NVw 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:
jReI+
pS eQ*gnV}rE% #pragma data_seg("shareddata")
/aK },+ HHOOK hHook =NULL; //钩子句柄
4TLh'?Xu9 UINT nHookCount =0; //挂接的程序数目
i} q6^;uTF static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
,@P3!| static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
]03!KE static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
`dj/Uk static int KeyCount =0;
_ p?q/-[4 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
M5<5(l #pragma data_seg()
rp
_G.C X=DJOepH' 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。
L\b$1U!i UP,(zKTA DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
'8}\! i& =B;)h BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
MHgS5b2 cKey,UCHAR cMask)
^m5{:\
Xk {
1 ft.ZJ BOOL bAdded=FALSE;
"e_ED* for(int index=0;index<MAX_KEY;index++){
v+\E%H if(hCallWnd[index]==0){
Oy H: hCallWnd[index]=hWnd;
UboOIx5: HotKey[index]=cKey;
*EotYT HotKeyMask[index]=cMask;
6E bAdded=TRUE;
s&c^Wr KeyCount++;
Jcy`:C\Ay break;
!x,3k\M }
AKS(WNGEp }
-5E<BmM return bAdded;
%`` FIv15w }
`E}2|9 //删除热键
']qC,;2 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
`_f3o,5 {
H#1/H@I# BOOL bRemoved=FALSE;
C#gQJ=!B for(int index=0;index<MAX_KEY;index++){
~>C!l k if(hCallWnd[index]==hWnd){
EmLPq!C if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
)>=`[$D1t hCallWnd[index]=NULL;
hwexv 9"" HotKey[index]=0;
#!<x|N?_< HotKeyMask[index]=0;
u'=#~'6 bRemoved=TRUE;
SK-|O9Ki KeyCount--;
& ??)gMM[ break;
t[#`%$%' }
1pcSfN :"1 }
Muarryh} }
~)()PO return bRemoved;
)hn,rmn
(P }
,@<-h* m }3+q}_3 xE + Go DLL中的钩子函数如下:
zmuq4-. U;;Har LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Qi[T!1 {
.%*.nq BOOL bProcessed=FALSE;
C@KYg/nYw if(HC_ACTION==nCode)
S_\RQB\l {
RzyEA3L' if((lParam&0xc0000000)==0xc0000000){// 有键松开
.}Xkr+
+] switch(wParam)
8y+Gvk: {
/Fk0j_b case VK_MENU:
'W$qi@f_s MaskBits&=~ALTBIT;
(L~3nN;rr break;
NeNKOW#X case VK_CONTROL:
;1"K79 MaskBits&=~CTRLBIT;
>0512_J+ break;
T nPC\.x case VK_SHIFT:
.&*Tj}p MaskBits&=~SHIFTBIT;
KnbP@!+c break;
u |#ruFR default: //judge the key and send message
vnIxI a break;
J :, }
DrW]`%Ql for(int index=0;index<MAX_KEY;index++){
FxD" z3D if(hCallWnd[index]==NULL)
H4%wq continue;
0{Tf;a< if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
FmnA+fA {
xv1$,|^ts SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
$'e.bh bProcessed=TRUE;
QO|ODW+D }
-'ZP_$sA }
|QHWX^pO }
%3FI>\3 else if((lParam&0xc000ffff)==1){ //有键按下
!3Pl]S~6! switch(wParam)
{\ .2h {
2b !b- case VK_MENU:
ib&
|271gG MaskBits|=ALTBIT;
Q>||HtF$A break;
&M<431y
case VK_CONTROL:
1f~_# EIC MaskBits|=CTRLBIT;
6Q\n<&,{ break;
9#_49euy|P case VK_SHIFT:
QI!:+8 MaskBits|=SHIFTBIT;
{x-g?HB break;
j^LnHVHk1 default: //judge the key and send message
Xst&QKU break;
4CNK ]2 }
i3f/{D/ for(int index=0;index<MAX_KEY;index++){
6g$+ ))g if(hCallWnd[index]==NULL)
yQ&;#`!' continue;
t6~|T_] if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
s'/ug {
64zO%F* SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
&(wik#S bProcessed=TRUE;
d'DS7F(c{ }
UY>{e>/H9 }
78 3a Z8 }
,/Xxj\i if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
pvcf_w`n for(int index=0;index<MAX_KEY;index++){
1OJ:Vy}n if(hCallWnd[index]==NULL)
t6LTGWs/_o continue;
v3`J~,V< if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
"zm.jNn SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
A(<-
U| //lParam的意义可看MSDN中WM_KEYDOWN部分
>a^H7kp }
bp5hS/A^1w }
mA{gj[@:x }
na%9E8;:&v return CallNextHookEx( hHook, nCode, wParam, lParam );
pW!] }
' Bdvqq zYH6+!VBH# 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:
`SOaQ|H
p61"a,Xc BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
x~KS;hA BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
I /RvU, (A"oMnjWd 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:
vW~_+:),e r?H {Y3, LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
4?8GK {
)v'3pTs2 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
DfqXw^BKD {
m@"!=CTKd //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
1eKJ46W SaveBmp();
e?F r/n return FALSE;
X/'B*y'=U }
5MiWM2"X\ …… //其它处理及默认处理
LgB}!OLQ }
i"U3wt|A R:OoQ^c yp!Xwq#n 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。
? p\'S
w: P`RM"'Om 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。
GAPZt4Z2 A.y"R)G 二、编程步骤
7!Fu.Ps
> v82@']IN 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";
OhIUm4=|$ j^:\a\-1 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
3",6 E( aiU n
bP 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;
`\#Qr|GC [NC^v.[1[ 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;
\5X34'7 V$^x]z 5、 添加代码,编译运行程序。
[gD02a:u T,jxIFrF 三、程序代码
%_}#IS1 0wxQ,PI1' ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
vzy/Rq #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
IHf
A;&b #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
ZH/|L?Q1U #if _MSC_VER > 1000
XBi@\i= #pragma once
vR#A7y @! #endif // _MSC_VER > 1000
Cf8(Jk`v| #ifndef __AFXWIN_H__
$eI[3{}X #error include 'stdafx.h' before including this file for PCH
Jd/5Kx #endif
]ujH7T #include "resource.h" // main symbols
4AUY8Pxp class CHookApp : public CWinApp
FL0[V, {
])0&el3- public:
@4hxGk= CHookApp();
*$uKg zv3 // Overrides
^8E/I]- // ClassWizard generated virtual function overrides
P0UMMn\-# //{{AFX_VIRTUAL(CHookApp)
awo=%vJ& public:
|
u36- virtual BOOL InitInstance();
mrk Q20D virtual int ExitInstance();
3^wJ4=^ //}}AFX_VIRTUAL
6lsU/`. //{{AFX_MSG(CHookApp)
)Z"7^i // NOTE - the ClassWizard will add and remove member functions here.
k'
pu%nWN // DO NOT EDIT what you see in these blocks of generated code !
h&.9Q{D //}}AFX_MSG
w QwY_ _ DECLARE_MESSAGE_MAP()
N4'b]:`n };
67Ge}6*2pd LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
hF!yp7l; BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
mn4j#- BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
h jWRU# BOOL InitHotkey();
pLrNYo*d BOOL UnInit();
S\GG(#b! #endif
'j>^L 90teXxg=| //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
P?\rRB #include "stdafx.h"
cXtL3T+ #include "hook.h"
Xs*~[k' #include <windowsx.h>
Mx0c
#d. #ifdef _DEBUG
^:LF #define new DEBUG_NEW
r'w5i1C+ #undef THIS_FILE
Zo'lvOpyZ static char THIS_FILE[] = __FILE__;
?RrJYj1 #endif
?9 2+(s #define MAX_KEY 100
C n4|qX"&t #define CTRLBIT 0x04
K\=bpc"Fy #define ALTBIT 0x02
bbS'ZkB\ #define SHIFTBIT 0x01
>aN@)=h} #pragma data_seg("shareddata")
eGtIVY/D HHOOK hHook =NULL;
< _c84,[V UINT nHookCount =0;
6'|J
; static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
+oe
~j\= static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
S &cH1QZ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
?Q:se static int KeyCount =0;
/vSFQ}W static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
vqv(KsD+:: #pragma data_seg()
>PL/>
HINSTANCE hins;
|M0 XLCNd_ void VerifyWindow();
goWD~'\ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
RhX
2qsva- //{{AFX_MSG_MAP(CHookApp)
TDy@Y>
) // NOTE - the ClassWizard will add and remove mapping macros here.
li,kW`j+t // DO NOT EDIT what you see in these blocks of generated code!
eAm7*2 //}}AFX_MSG_MAP
l&U3jeW-o END_MESSAGE_MAP()
e Hd{'J< Q
Gn4AW_ CHookApp::CHookApp()
oKzV!~{0M; {
hTH"jAC+ // TODO: add construction code here,
>-EoE;s // Place all significant initialization in InitInstance
DlfXzKn; }
/8J2,8vZ SJIJV6}H CHookApp theApp;
9S.R%2xw` LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
kZSe#'R's {
K#+TCZ, BOOL bProcessed=FALSE;
~F
uD6f if(HC_ACTION==nCode)
LP#CA^*S {
8t0i
j if((lParam&0xc0000000)==0xc0000000){// Key up
"x3_cA~ switch(wParam)
[Z~>7ayF+) {
^EZ)NG=e5 case VK_MENU:
r 3pfG MaskBits&=~ALTBIT;
w[:5uo( break;
ra$_#HY case VK_CONTROL:
tJ2l_M^ MaskBits&=~CTRLBIT;
69O?sIk break;
<$,iYx case VK_SHIFT:
8t9sdqM/C MaskBits&=~SHIFTBIT;
\`|,wLgH break;
r(%#@?& default: //judge the key and send message
ax7ub break;
:t^=~xO9 }
F2>o"j2 for(int index=0;index<MAX_KEY;index++){
|)
THuE( if(hCallWnd[index]==NULL)
G'}%m;-mt continue;
|;9OvR> A if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
2!{CNt.- {
[@Uc4LX SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
t~,!a? S7 bProcessed=TRUE;
Kze\|yJ }
{K_YW }
TS-m^Y'R }
mY dU`j else if((lParam&0xc000ffff)==1){ //Key down
}5zH3MPQH switch(wParam)
cf@:rHB} {
h#;fBQ]
case VK_MENU:
7-6_`Q2}Y MaskBits|=ALTBIT;
$?wX* break;
#^xiv/sV case VK_CONTROL:
~wh8)rm MaskBits|=CTRLBIT;
Ca?pK_Y break;
AO>K
6{ case VK_SHIFT:
_EjS(.e/= MaskBits|=SHIFTBIT;
/`:5#O break;
_pjpPSV6J default: //judge the key and send message
s:w LEj+ break;
cg$7`/U }
@ iao"& for(int index=0;index<MAX_KEY;index++)
]5rEwPB {
{3
zq.e{ if(hCallWnd[index]==NULL)
EC?!%iO` continue;
4)Z78H%> if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
%w'@:~0 {
S WYiI SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
+!.=M8[ bProcessed=TRUE;
"4n_MV>p }
5x4(5c5^ }
8%vk"h:u: }
1fEV^5I if(!bProcessed){
V"T;3@N/4 for(int index=0;index<MAX_KEY;index++){
.CwMxuW if(hCallWnd[index]==NULL)
vV8y_ continue;
kmo3<'j{ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
{jggiMwo.v SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
{IqbO>|"O_ }
k@KX=mG< }
(fY (- }
6D w[n return CallNextHookEx( hHook, nCode, wParam, lParam );
~;Xdz/ }
rf^1%Zo: 19;\:tN BOOL InitHotkey()
GJ{]}fl {
qo$<&'r if(hHook!=NULL){
o )Ob}j nHookCount++;
`Z/"Dd;F^3 return TRUE;
1mf|:2, }
vIz~B2%x else
J}%&;uv
hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
HQv#\Xi1 if(hHook!=NULL)
M6y:ze nHookCount++;
"d%":F( return (hHook!=NULL);
Y7!,s-v4W }
a;([L8^7$l BOOL UnInit()
'OkF.bs {
CW, Kw if(nHookCount>1){
6
)xm?RK nHookCount--;
spd>.Cm` return TRUE;
Y~fds#y0 }
S(9fGh BOOL unhooked = UnhookWindowsHookEx(hHook);
=;^2#UxXA& if(unhooked==TRUE){
]7c715@ nHookCount=0;
e@=Bl- hHook=NULL;
}
Tp!Ub\Cc }
kAf2g return unhooked;
)6IO)P/Q~ }
WAkKbqJV mA3C)V BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
*jf
(TIU {
~H)b vN^ BOOL bAdded=FALSE;
3ef]3 for(int index=0;index<MAX_KEY;index++){
8;Yx a8i e if(hCallWnd[index]==0){
cKF 8( hCallWnd[index]=hWnd;
4}fG{Bk HotKey[index]=cKey;
o D:?fs] HotKeyMask[index]=cMask;
\BUr2] bAdded=TRUE;
L[Tr"BW KeyCount++;
!XzRV?Ih; break;
R9fM9 }
/R 2:Js }
oy#Qj3M8= return bAdded;
wGLZzqgq }
PL%_V ?z n uhKM.a{ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
|;Jcf3e( {
NC@OmSR\0 BOOL bRemoved=FALSE;
z.P)
:Er for(int index=0;index<MAX_KEY;index++){
v\0[B jhL? if(hCallWnd[index]==hWnd){
W[w8@OCNf if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
^5j9WV hCallWnd[index]=NULL;
|c dQJW HotKey[index]=0;
F0+ u#/# HotKeyMask[index]=0;
]"{K5s7 bRemoved=TRUE;
iS=}| 8" KeyCount--;
4CfPa6_ break;
}(20MW8rMc }
^'6!)y# }
yC6XO&:g }
9q;+ Al^Z return bRemoved;
rFdq \BSi }
wUW+S5"K 'SvYZ0ot void VerifyWindow()
5Y_)%u
{
%0$$tS + for(int i=0;i<MAX_KEY;i++){
K7U` if(hCallWnd
!=NULL){ Fl<BCJY
if(!IsWindow(hCallWnd)){ ()=
hCallWnd=NULL; q%8,@xg
HotKey=0; r;I3N+
HotKeyMask=0; .K XpB7:
KeyCount--; jrZM
} IbF[nQ
} Mm+_>
} 50Pz+:
} |SQ5 Sb
Et4gRS)\
BOOL CHookApp::InitInstance() >Vn;1 |w
{ shjS^CP
AFX_MANAGE_STATE(AfxGetStaticModuleState()); gGH<%nHW1
hins=AfxGetInstanceHandle(); 7b \Hbg Z
InitHotkey(); aXhgzI5]
return CWinApp::InitInstance(); ]B5q v6
} ?b:l.0m
egK,e?~
int CHookApp::ExitInstance() aOA;"jR1
{ +tES:3Pi
VerifyWindow(); =Y?M#3P.I
UnInit(); nO,<`}pV
return CWinApp::ExitInstance(); _<yJQ|[z~i
} 'k{pWfn=<
8{(;s$H~
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file p4*VE5[?_+
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) o}
YFDYi
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ |!aMj8i2
#if _MSC_VER > 1000 Jp=ur)Dj
#pragma once E,>/6AU
#endif // _MSC_VER > 1000 VSL6tQp
"U4Sn'&h@
class CCaptureDlg : public CDialog
4b,N"w{v
{ {%)bxk6
// Construction fnN"a Z
public: )apqL{u:=
BOOL bTray; -;Y*;xe
BOOL bRegistered; c7[|x%~
BOOL RegisterHotkey(); C;-9_;&
UCHAR cKey; 7D|g|i
UCHAR cMask; )k.;.7dXe
void DeleteIcon(); b$l@Z&[]
void AddIcon(); +DY% Y
`0
UINT nCount; %D)W~q-g
void SaveBmp(); nNSq6 Cj
CCaptureDlg(CWnd* pParent = NULL); // standard constructor soRt<