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:
OC(S"&D
v$H=~m 一、实现方法
>%x N?% fMGL1VN 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:
/&PRw<}>_o EL--?<g #pragma data_seg("shareddata")
]f%yeD HHOOK hHook =NULL; //钩子句柄
M|HW$8V3_2 UINT nHookCount =0; //挂接的程序数目
(4;m*'X static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
(Nzup3j static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
y,D@[*~Xb static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
]VuB2L[D static int KeyCount =0;
O/Q7{5n static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
wNNInS6 #pragma data_seg()
0[/GEY@ R&lJ& SgC 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
UG@9X/l} olHT* mr DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
2hD(zUSy lfle7; BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
Mp%.o}j
cKey,UCHAR cMask)
p }p@])}8 {
4Z'/dI` BOOL bAdded=FALSE;
!c 3c%=W for(int index=0;index<MAX_KEY;index++){
^`BiA'gPPC if(hCallWnd[index]==0){
-'q#u C hCallWnd[index]=hWnd;
8ClOd<I HotKey[index]=cKey;
z' oK
0" HotKeyMask[index]=cMask;
!06
!`LT bAdded=TRUE;
%A]?5J)Bi KeyCount++;
E.ugr]) break;
!+<OED=qe }
Z}b25) }
G)(vd0X1 return bAdded;
D'Fj"&LK }
qdss(LZ //删除热键
\3WF-!xe BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
.el&\Jt {
()Tl\ BOOL bRemoved=FALSE;
pm)kocG for(int index=0;index<MAX_KEY;index++){
Wqy\yS [ if(hCallWnd[index]==hWnd){
=sp5.-r if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Ci?BJ, hCallWnd[index]=NULL;
_m?TEqB HotKey[index]=0;
4@qHS0$ HotKeyMask[index]=0;
*VP-fyJp bRemoved=TRUE;
sf7~hN*
KeyCount--;
t\\oGH break;
[WfigqY`b* }
PU& v{gn }
B4l*]K% }
2aDjt{7P return bRemoved;
` FJ2
? }
u0o}rA %z9lCTmy z_;:6*l=: DLL中的钩子函数如下:
`rWT^E@p5m 5.IX LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
pW
y+oZ {
tz6N,4J? BOOL bProcessed=FALSE;
M/d6I$~7z if(HC_ACTION==nCode)
?o>JX.Nl&7 {
B'AU~#d if((lParam&0xc0000000)==0xc0000000){// 有键松开
XCN^>ToD switch(wParam)
SV?^i ` {
Y&![2o.Q case VK_MENU:
=ws iC' MaskBits&=~ALTBIT;
ZyJ-}[z break;
B(eC|:w[z case VK_CONTROL:
*wfb~&:} MaskBits&=~CTRLBIT;
Y<ZaW{% break;
[iO*t,3@h case VK_SHIFT:
I:l/U-b7h MaskBits&=~SHIFTBIT;
VZhHO
d break;
d~|/LR5 default: //judge the key and send message
8:9/RL\"x break;
?q*,,+'0 }
ZUA%ZkX=F for(int index=0;index<MAX_KEY;index++){
]%Db %A if(hCallWnd[index]==NULL)
:`Z'vRj continue;
4#MPD if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
='[J. {
\nzaF4+$ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
C"gH>G bProcessed=TRUE;
gP13n!7 }
'(6
^O= }
>V,i7v*? }
Z=I+_p_G else if((lParam&0xc000ffff)==1){ //有键按下
jYxmU8 switch(wParam)
B-.QGf8K. {
VoGyjGt& case VK_MENU:
o-}q|tD$< MaskBits|=ALTBIT;
=/Lwprj break;
L>ruNw'-K case VK_CONTROL:
_u]S/X- MaskBits|=CTRLBIT;
^&|KuI+u break;
n>o0PtGxC case VK_SHIFT:
o4U[;.?c MaskBits|=SHIFTBIT;
Z'<I
Is:J break;
R'z
-#*[ default: //judge the key and send message
ir?Y> break;
=qNZ7>Qw }
o9JZ-biH for(int index=0;index<MAX_KEY;index++){
iD(+\:E if(hCallWnd[index]==NULL)
#;lB5) oe continue;
!RPPwvNk4 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
h!!7LPxt {
^5{0mn_4i
SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
. 1q4Q\B< bProcessed=TRUE;
.Bs~FIe^ }
e.n*IJ_fz }
hgU#2`fS }
!xRboPg if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
}rKKIF^f\S for(int index=0;index<MAX_KEY;index++){
.B? J@, if(hCallWnd[index]==NULL)
9^zA( continue;
`at>X&Ce, if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
,UA-Pq3} SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
@&F\ M} //lParam的意义可看MSDN中WM_KEYDOWN部分
T!ik"YZ@i }
$j"TPkW{M }
|9;MP&68 }
Y2oN.{IH return CallNextHookEx( hHook, nCode, wParam, lParam );
LvcGh }
Mv 1V
Vk ln*_mM/Q% 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
BIn7<.& ;XDGlv% BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
OGGuV Y BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
*B0
7- +]*hzWbe 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
vUD>+*D k0>]7t$L LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
8)m {
wF.S ,| if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
){M)0,: {
_c@k>"_{S //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
|Ev VS SaveBmp();
J69B1Yi return FALSE;
yu98d1 }
6d#:v"^, …… //其它处理及默认处理
[}1+=Ub }
%{j)w{
LJ '>aj5tZ>R wS%j!|xhlV 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。
M?3#XQDvD 7eP3pg# 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。
JXNfE,_ #-^y9B 二、编程步骤
l6y*SW5+ q*pWx]Y 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";
=e!o x4e8;A(y 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
4)OM58e} iO2%$Jw9\ 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
!Bqmw E#^?M#C 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
w.0:#4 fo5+3iu^ 5、 添加代码,编译运行程序。
7TaHE
Hp1n*0%dZ& 三、程序代码
F =Zc_ d:%!)s ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
*0!IHr"fn #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
<7X6ULQ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
m@#@7[6]o #if _MSC_VER > 1000
y'21)P #pragma once
LE>b_gQ$
2 #endif // _MSC_VER > 1000
:,*{,^2q: #ifndef __AFXWIN_H__
u^Ss8}d #error include 'stdafx.h' before including this file for PCH
|j>fsk~ #endif
Xx;4 #include "resource.h" // main symbols
!^*-]p/z class CHookApp : public CWinApp
U%zZw) {
oHvVZ public:
NUjo5.7 CHookApp();
\Bg?QhA_D // Overrides
B 4my // ClassWizard generated virtual function overrides
j ?gscQ3 //{{AFX_VIRTUAL(CHookApp)
Q4!6|%n8v public:
Smjg[ virtual BOOL InitInstance();
48t_?2> virtual int ExitInstance();
*j/[5J0'M //}}AFX_VIRTUAL
/GDGE } //{{AFX_MSG(CHookApp)
ET:B" // NOTE - the ClassWizard will add and remove member functions here.
Q?7:XbN // DO NOT EDIT what you see in these blocks of generated code !
+~] :oj //}}AFX_MSG
GT(nW|v DECLARE_MESSAGE_MAP()
jn/
J-X= };
f6O5k8n LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
qTd6UKg BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
7]&ouT BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
b :J$ BOOL InitHotkey();
M>kk"tyM BOOL UnInit();
CDRkH)~$ #endif
/:o (Ghc? !5escR!\D //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
MDqUl:] #include "stdafx.h"
%I>-_el #include "hook.h"
Or9`E( #include <windowsx.h>
;xMieqz #ifdef _DEBUG
SWZA`JVK #define new DEBUG_NEW
@2eV^eO9 #undef THIS_FILE
{;[W'Lc static char THIS_FILE[] = __FILE__;
IP
e"9xb #endif
wg0hm#X #define MAX_KEY 100
w\f>.N #define CTRLBIT 0x04
kV$$GLD\ #define ALTBIT 0x02
YnLwBJ 2i #define SHIFTBIT 0x01
L^Q q[> #pragma data_seg("shareddata")
TP-<Lhy HHOOK hHook =NULL;
H.R7,'9 UINT nHookCount =0;
2B<0|EGtzw static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
fNllF,8} static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
YLO/J2[' static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
JRT,%;*, static int KeyCount =0;
*k%3J9=-1 static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
}M+2 ,#l #pragma data_seg()
$GcVI;a HINSTANCE hins;
JLZ=$ d void VerifyWindow();
LsGu-Y5^ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
G"._]3CPF //{{AFX_MSG_MAP(CHookApp)
tUR9ti // NOTE - the ClassWizard will add and remove mapping macros here.
>QJfTkD$ // DO NOT EDIT what you see in these blocks of generated code!
y7x[noGtR //}}AFX_MSG_MAP
j^&{5s END_MESSAGE_MAP()
y5AJ1A6?E 8fI&-uP{g CHookApp::CHookApp()
LNR~F_64Q {
|'bRVqJ // TODO: add construction code here,
5[{#/!LX) // Place all significant initialization in InitInstance
MaX:oGF, }
!`VC4o tq^d1b(j4 CHookApp theApp;
m?$peRn3{ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
o"5[~$O {
oF9c>^s BOOL bProcessed=FALSE;
C"=^(HU if(HC_ACTION==nCode)
HvSYE[Zt| {
Edi`x5"l if((lParam&0xc0000000)==0xc0000000){// Key up
!o k6*m switch(wParam)
Gd08RW {
m=7Z8@sX}, case VK_MENU:
*w[\(d'T MaskBits&=~ALTBIT;
J|D$ break;
ZKT~\l case VK_CONTROL:
"BAH=ul5E MaskBits&=~CTRLBIT;
V7qc9Gd@I break;
QxjX:O case VK_SHIFT:
nR()ei^X MaskBits&=~SHIFTBIT;
[=xJh?*P break;
qauZ-Qoc9 default: //judge the key and send message
QaMB=wVr break;
/V%]lmxQ }
{g7[3WRy for(int index=0;index<MAX_KEY;index++){
AvNU\$B4aG if(hCallWnd[index]==NULL)
|y*-)t continue;
;& PK6G if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
$^1L|KgXp {
KOQ9K SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
DIU9Le bProcessed=TRUE;
e yLVu. }
+uY)MExs2 }
3n=`SLj/a }
s?2DLXv}! else if((lParam&0xc000ffff)==1){ //Key down
m@_m"1_; switch(wParam)
%j=xL V\ {
't5 I%F case VK_MENU:
L`!M3c@u MaskBits|=ALTBIT;
i47xF7y\ break;
ps*dO case VK_CONTROL:
1`X-
O> MaskBits|=CTRLBIT;
{ta0dS;1 break;
j+>#.22+ case VK_SHIFT:
g[,1$39Z|@ MaskBits|=SHIFTBIT;
>nnjLrI break;
=CE(M},d default: //judge the key and send message
fzVU9BU break;
ZPISclSA+
}
)E2^G)J$W for(int index=0;index<MAX_KEY;index++)
i{$h]D_fD {
,z1fiq if(hCallWnd[index]==NULL)
>,JA=s continue;
kZ0|wML8 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
bxS+ R\ {
UW%.G SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
gtBnP~zT\B bProcessed=TRUE;
Ve1O<i }
71h?t`N }
N{(Q,+ ~ }
f~3_Rv! if(!bProcessed){
CX8tTbuFl for(int index=0;index<MAX_KEY;index++){
~
}<!ON; if(hCallWnd[index]==NULL)
^.d97rSm continue;
tv+H4/ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
N~%F/`Z<+ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
~alC5|wCUQ }
gD\ = }
MR/8 }
$6c8<!B_ return CallNextHookEx( hHook, nCode, wParam, lParam );
l]s,CX }
^:0epj7 <u"h'e/oW_ BOOL InitHotkey()
U1>VKP;5Nn {
{cNH| if(hHook!=NULL){
ZL3aO,G2 nHookCount++;
'e3[m return TRUE;
_TRO2p0 }
{iv!A=jld else
r#K;@wu2 hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
|Q'l&Gt6 if(hHook!=NULL)
D&xbtJd nHookCount++;
u'?yc"d># return (hHook!=NULL);
U*Hw
t\ }
`W8A* BOOL UnInit()
qGE?[\t[6 {
,AC+s"VS if(nHookCount>1){
9*@K l`\ nHookCount--;
-'tgr6=|w" return TRUE;
#NAlje( 7 }
95,{40;X7 BOOL unhooked = UnhookWindowsHookEx(hHook);
N|,6<| if(unhooked==TRUE){
0$n0fu nHookCount=0;
r2EIhaGF; hHook=NULL;
E! i:h62 }
!zw)! rV= return unhooked;
P|[i{h }
0.^9)v*i ^XV=(k;~bX BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
1|L3} 2 {
9M)N2+hkZ BOOL bAdded=FALSE;
S >P TD@ for(int index=0;index<MAX_KEY;index++){
Lmy ^/P% if(hCallWnd[index]==0){
ugM,wT&~Y hCallWnd[index]=hWnd;
dz',!|> HotKey[index]=cKey;
v@43%`"Gj HotKeyMask[index]=cMask;
tNskB`541 bAdded=TRUE;
0Wf,SYx`s KeyCount++;
}Om+,!_d break;
TB]Bl. }
r$~w3yN)v }
oJF@O:A return bAdded;
s^nwF> }
MSmvQ n')#]g0[ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
EV:y} {
("t;
2Mw BOOL bRemoved=FALSE;
c1IK9X* for(int index=0;index<MAX_KEY;index++){
])=k";76 if(hCallWnd[index]==hWnd){
o9!DK if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
UQwLAXs hCallWnd[index]=NULL;
acWm+ HotKey[index]=0;
Vo%MG.IPB HotKeyMask[index]=0;
y[*Bw)F\N bRemoved=TRUE;
zS*X9|p KeyCount--;
Z#wmEc.}C break;
^/Id!Y7 }
eD0Rv0BV^ }
]_S&8F}| }
=o5ZcC return bRemoved;
-Bqn^ E
}
~;Ga65_6_ aDx{Q& void VerifyWindow()
H)$-T1Wx4 {
7XE/bhe%S for(int i=0;i<MAX_KEY;i++){
"}i\"x;s if(hCallWnd
!=NULL){ 8J:6uO
c|
if(!IsWindow(hCallWnd)){ %Dg]n4f
hCallWnd=NULL; _LV;q! /j
HotKey=0; =Tf
uwhV
HotKeyMask=0; af]&3(33
KeyCount--; *`:zSnu
} iPMI$
} eKlh }v
} 0k I.dX)
} `Jh> 1l
6]dK,
BOOL CHookApp::InitInstance() 8X`Gm!)
{ c <[?Z7y
AFX_MANAGE_STATE(AfxGetStaticModuleState()); @Z.s:FV[
hins=AfxGetInstanceHandle(); |IqQ%;H
InitHotkey(); K9FtFd
return CWinApp::InitInstance(); Vcg$H8m
} gqaENU>
,z1X{
int CHookApp::ExitInstance() )o'&f"/
{ dZ&/Iz
VerifyWindow(); odPq<'V|AY
UnInit(); &N!QKrj3
return CWinApp::ExitInstance(); BzL>,um
} Qo{Ez^q@J
00'R1q4
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file C+-xC~
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 8$3G c"=
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ m'$]lf;*
#if _MSC_VER > 1000 %|[+\py$Q
#pragma once 7WG"_A~V
#endif // _MSC_VER > 1000 RsS?ibozl
SrfDl*
class CCaptureDlg : public CDialog D+/27#
{ tY<D\T
// Construction rrei6$H&
public: F4i
c^F{K
BOOL bTray; 4r!8_$fN?G
BOOL bRegistered; ]3<k>?
BOOL RegisterHotkey(); <qs>c<Vj
UCHAR cKey; =$UDa`}D
UCHAR cMask; Kw}-<y
void DeleteIcon(); 4,kT4_&,
void AddIcon(); 08&DP^NS
UINT nCount; N^A&DrMF
void SaveBmp(); /#M|)V*wn
CCaptureDlg(CWnd* pParent = NULL); // standard constructor *P&ZE
// Dialog Data Hq h
//{{AFX_DATA(CCaptureDlg) *p{wC
r
enum { IDD = IDD_CAPTURE_DIALOG }; 8Letpygm
CComboBox m_Key; -E#!`~&V
BOOL m_bControl; O0#wM-M
BOOL m_bAlt; DG&14c>g
BOOL m_bShift; >Liv].
CString m_Path; -tWkN^j8+
CString m_Number; ^1M :wXr
//}}AFX_DATA oJy ]n9
// ClassWizard generated virtual function overrides [^B04x@
//{{AFX_VIRTUAL(CCaptureDlg) _ 97
public: w?A&X