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:
7xT[<?,
o_rtH|ntX5 一、实现方法
T VeJ6 jyQVSQs 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:
mp:m`sh*i gQ+9xT d #pragma data_seg("shareddata")
e8q4O|I_ HHOOK hHook =NULL; //钩子句柄
,]q%/yxi UINT nHookCount =0; //挂接的程序数目
jCQho-1QN static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
K(3&27sGN static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
P^zy; Qs7 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
A{(T'/~" static int KeyCount =0;
41}/w3Z4 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
DxfMqH[vs #pragma data_seg()
ls @5^g ANb"oX c 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。
wv^b_DR
Q;20T 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:
+'%\Pr( afUTAP@ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
(Fqa][0 cKey,UCHAR cMask)
@ef$b?wg {
RH~sbnZ)F BOOL bAdded=FALSE;
b{pg!/N4 for(int index=0;index<MAX_KEY;index++){
Hg whe=P if(hCallWnd[index]==0){
jb3.W hCallWnd[index]=hWnd;
u`6/I#q` HotKey[index]=cKey;
i6 L HotKeyMask[index]=cMask;
F`srE6H
bAdded=TRUE;
|D<+X^0' KeyCount++;
q,@+^aZ break;
m^A]+G#/ }
)Mi'(C; }
`
FxtLG,F return bAdded;
U`1l8'W}:# }
4+Ti7p06&\ //删除热键
blp=Hk BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
BKZ v9 {
,R~eY?{a BOOL bRemoved=FALSE;
Azn:_4O for(int index=0;index<MAX_KEY;index++){
-|[~sj-p if(hCallWnd[index]==hWnd){
?Pnx~m{%* if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
QnU0"_- hCallWnd[index]=NULL;
r--;yEjWE HotKey[index]=0;
Fr;lG HotKeyMask[index]=0;
9P0yv3 bRemoved=TRUE;
Pgev) rh[ KeyCount--;
/RqhykgZ break;
l5HWZs^ }
HlRAD|]\ }
XHQh4W3 }
ppFYc\&= return bRemoved;
n ,1tD }
6(.H3bu 1J'pB;.]s =qX*] DLL中的钩子函数如下:
$',3Pv ^ $wJi9D6 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
"l2bx {
]#5^&w)' BOOL bProcessed=FALSE;
2&x7W* if(HC_ACTION==nCode)
oZ-FF' {
GA ik;R if((lParam&0xc0000000)==0xc0000000){// 有键松开
8f-:d] switch(wParam)
;dOs0/UM& {
@G(xaU'u case VK_MENU:
JCcQd01z MaskBits&=~ALTBIT;
{,Fcd(MU break;
r{Z[xWIX case VK_CONTROL:
SB1[jcJ MaskBits&=~CTRLBIT;
zDd5cxFdZ break;
X'@f"= v9k case VK_SHIFT:
hHEPNR[.
MaskBits&=~SHIFTBIT;
$+TYvA'N break;
z5 pc3: default: //judge the key and send message
~<eVl
l= break;
oAnigu; }
K7Gm-=% for(int index=0;index<MAX_KEY;index++){
}9=2g`2Q if(hCallWnd[index]==NULL)
]ViOr8u continue;
iD`k"\>9 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
HL8(lPgS {
5 H *> SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
h~fWE bProcessed=TRUE;
uP Rl[tS0 }
gDv$DB8- }
HT&p{7kFm }
O4N-_Kfp/ else if((lParam&0xc000ffff)==1){ //有键按下
Efvq?cG& switch(wParam)
bKByU{t {
JaFUcpZk$ case VK_MENU:
yl]UUBcQ MaskBits|=ALTBIT;
&N9IcNP break;
%ZuLl( case VK_CONTROL:
(Xj.iP MaskBits|=CTRLBIT;
>|(%2Zl break;
z{' 6f@] case VK_SHIFT:
f)U6p MaskBits|=SHIFTBIT;
5}7ISNP;f break;
y<v|X2 default: //judge the key and send message
T g{UK break;
cyHU\!Z*Zq }
c>rKgx for(int index=0;index<MAX_KEY;index++){
{=6)SBjf if(hCallWnd[index]==NULL)
Vpw[B.v continue;
5Edo%Hd6 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
C/y(E|zC$ {
zU
b8NOi SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
44j,,k bProcessed=TRUE;
]<q'U> N }
7dHIW!OA }
W6M jQ%f }
vs\|rLa if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
'{CWanTPi for(int index=0;index<MAX_KEY;index++){
`{<JC{yc? if(hCallWnd[index]==NULL)
L&'l3| continue;
L:i+}F;M)s if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
gZ*hkKN6 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
t*s!0'Y //lParam的意义可看MSDN中WM_KEYDOWN部分
]\`w1'* }
19) !$Hl }
%}ixgs7*c0 }
V pH|R return CallNextHookEx( hHook, nCode, wParam, lParam );
*k4+ioFnKE }
L W?&a3e V $>"f( 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
([tG y ~hzEKvs BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
QheDF7'z BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
A'`P2Am &8afl"_~ 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
s_v}=C^ q}e]*]dJZ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
POY=zUQ'/ {
BJ2Q 2WW if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
d{3I.$ThH {
^9s"FdB]24 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
~Zu}M>-^c, SaveBmp();
Z>&K&ttJ return FALSE;
97(n\Wt2 }
3r`<(%\ …… //其它处理及默认处理
{>A
8g({i }
k5C>_(
A {<r`5 G_0)oC@Jl: 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。
`;e^2 Q84t9b 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。
;!:F#gahv rX:1_q`xA 二、编程步骤
x~nQm]@`h 6}"lm]b 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";
L*v93;|s 9[Y*k^.! 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
C-r."L K]9tc) 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;
tbY SK =:;YTie 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;
xp(mB7;: HI z9s4Y_ 5、 添加代码,编译运行程序。
ZRUh/<\[ [C2kK *JZ 三、程序代码
I IYL A( \1~I04'= ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
PJ}[D.elO #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
-h=c=P #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
dbg|VoNf #if _MSC_VER > 1000
tgc@7 #pragma once
ea>[BB3# #endif // _MSC_VER > 1000
[1mIdwS #ifndef __AFXWIN_H__
bIq-1
Y( #error include 'stdafx.h' before including this file for PCH
Xa>}4j. #endif
|fx#KNPf] #include "resource.h" // main symbols
NPP3(3C class CHookApp : public CWinApp
+H[Q~P8'[ {
Bg5;Q) public:
%@o&*pF^, CHookApp();
u^!&{ q // Overrides
A
xRl*B // ClassWizard generated virtual function overrides
{Qm6?H //{{AFX_VIRTUAL(CHookApp)
?F9hDLX public:
!\3}R25 virtual BOOL InitInstance();
o%$<LaQG5 virtual int ExitInstance();
= >P_mPP= //}}AFX_VIRTUAL
|HNQ|r_5S //{{AFX_MSG(CHookApp)
p
FXd4* // NOTE - the ClassWizard will add and remove member functions here.
MwN1]d|6 // DO NOT EDIT what you see in these blocks of generated code !
HK^a:BI //}}AFX_MSG
PMD,8] | DECLARE_MESSAGE_MAP()
X
E!2Q7Q9 };
?!R%o LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
{7/ A BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
#wGQv BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
AUu5g BOOL InitHotkey();
%}\ vW BOOL UnInit();
K90D1sD #endif
-aC!0O y` t7sUtmq
//////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
~>.awu+o| #include "stdafx.h"
neK*jdaP #include "hook.h"
,o4r,.3[s #include <windowsx.h>
S$Qr@5 #ifdef _DEBUG
\\y}DNh #define new DEBUG_NEW
SIj6.RK #undef THIS_FILE
iZsau2K static char THIS_FILE[] = __FILE__;
{6-;P#Q0_ #endif
|+>%o.M&i #define MAX_KEY 100
^u= PdBY #define CTRLBIT 0x04
2LtU;}7s #define ALTBIT 0x02
^
yY{o/6 #define SHIFTBIT 0x01
M}R@ K;%
#pragma data_seg("shareddata")
8+=p8e~An HHOOK hHook =NULL;
yLV2>kq UINT nHookCount =0;
AECxd[k$9 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
|2WxcW]U.% static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
Q9Q!9B@ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
,<`|-oa static int KeyCount =0;
pg5@lC]J static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
rE!G,^_{ #pragma data_seg()
Y'3kE HINSTANCE hins;
D!81(}p void VerifyWindow();
tU8g(ep,o BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
!E4E' I=]N //{{AFX_MSG_MAP(CHookApp)
tn(f rccy // NOTE - the ClassWizard will add and remove mapping macros here.
GZxglU,3T // DO NOT EDIT what you see in these blocks of generated code!
;a#}fX //}}AFX_MSG_MAP
Sn_z END_MESSAGE_MAP()
i=,B88ko WHZe)|n CHookApp::CHookApp()
Q=)"om {
hWl""66+5 // TODO: add construction code here,
$71i+h]_ // Place all significant initialization in InitInstance
a*pXrp@ }
3s88#_eT ?{y:s!! CHookApp theApp;
wghFGHgw LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
NN31?wt {
6R3"L]J BOOL bProcessed=FALSE;
n0Qh9*h if(HC_ACTION==nCode)
:u[
oc. {
48R]\B<R{ if((lParam&0xc0000000)==0xc0000000){// Key up
b'1/cY/! switch(wParam)
Q1P,=T@ {
*[XN.sb8E case VK_MENU:
7I @9v=xV MaskBits&=~ALTBIT;
Qi(e`(,' break;
?,A}E|jZ case VK_CONTROL:
yfRUTG MaskBits&=~CTRLBIT;
03i?"MvNo break;
P wt ?9I case VK_SHIFT:
<k!mdj) MaskBits&=~SHIFTBIT;
c,b`N0dOKL break;
c,g]0S?gu default: //judge the key and send message
0KWy?6 X break;
#QJ4o_ }
H]T2$'U6 for(int index=0;index<MAX_KEY;index++){
$9j>VGf= if(hCallWnd[index]==NULL)
n1k$)S$iiy continue;
< -@, if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
nr<}Hc^f- {
H4,.H,PZ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
m!FM+kge bProcessed=TRUE;
5~<a>> }
IPr*pQ{;c }
Xr
}
_oMs
`"4K else if((lParam&0xc000ffff)==1){ //Key down
$=@9 D,R switch(wParam)
7(nz<z p {
C+Fh$ case VK_MENU:
\'}/&PCkr MaskBits|=ALTBIT;
jL>I5f break;
h&:Q$*A> case VK_CONTROL:
2V=FWuXC" MaskBits|=CTRLBIT;
Q(!}t"u break;
Kq@m?h case VK_SHIFT:
|}]JWsuB MaskBits|=SHIFTBIT;
V29S* break;
eNlF2M default: //judge the key and send message
J*^,l`C/ break;
p;c_<>ws-Y }
HNkZ1+P { for(int index=0;index<MAX_KEY;index++)
b_K?ocq {
47(1V/r if(hCallWnd[index]==NULL)
%~8](]p continue;
3;-@<9 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
/
%U~lr {
TQbFI;\ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
cx1WGbZ bProcessed=TRUE;
jl 30\M7 }
sJjl)Qs)T }
>? A `C!i }
+QCU]Fozk if(!bProcessed){
[][:/~q! for(int index=0;index<MAX_KEY;index++){
tnKpn-LPA if(hCallWnd[index]==NULL)
TS~Y\Cp continue;
709Uv5 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
,h5-rw' SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
{C,1w }
yv#c=v| }
8g2-8pa{ }
i\DHIzGp[ return CallNextHookEx( hHook, nCode, wParam, lParam );
5qeS|]^` }
R;Gl{ X-;Qorb^ BOOL InitHotkey()
6S+K*/w {
yEw"8u' if(hHook!=NULL){
Wj f>:\w nHookCount++;
cQ8$,fo return TRUE;
_nIqy&< }
mw4'z,1Q else
9 FFfRIVY hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
8n. "5,P if(hHook!=NULL)
ixI5Xd< nHookCount++;
_sf0{/< ) return (hHook!=NULL);
9-Nq[i" }
:vgh
KI BOOL UnInit()
nV,{w4t+ {
>1)@n3. <O if(nHookCount>1){
1X!f!0=g+ nHookCount--;
lJz?QI1 return TRUE;
YVg}q#
}
@e?[oojrM BOOL unhooked = UnhookWindowsHookEx(hHook);
u`H@Q&(^wa if(unhooked==TRUE){
bTy'5" nHookCount=0;
3Mh,NQB hHook=NULL;
T0]%(F/8 }
7&;jje[
<g return unhooked;
q3pN/f;kr, }
ja,L)b: p#8LQP~0$ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
xjn8)C {
PE6u8ZAb" BOOL bAdded=FALSE;
a*n%SUP for(int index=0;index<MAX_KEY;index++){
Ow .)h(y/ if(hCallWnd[index]==0){
Ppo^qb hCallWnd[index]=hWnd;
?/|@ #& HotKey[index]=cKey;
Zy+QA>d| HotKeyMask[index]=cMask;
/NN[gz bAdded=TRUE;
uI:3$ KeyCount++;
|@Idf`N$ break;
r1az=$ }
Cak/#1 }
"<n"A7e return bAdded;
/x8C70W^ }
:]z-Rz zHum&V8=H BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
>"$-V Y6 i {
5z(>4 d! BOOL bRemoved=FALSE;
.T$9Q Ar5 for(int index=0;index<MAX_KEY;index++){
!y2h`ZAZ if(hCallWnd[index]==hWnd){
d`q)^ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
(!&O4C5 hCallWnd[index]=NULL;
XX5(/# HotKey[index]=0;
+n.j.JP"X HotKeyMask[index]=0;
4[V6so 0 bRemoved=TRUE;
*d,n2a#n5 KeyCount--;
hb8@br break;
K&P{2Hndr }
*~oDP@[S }
-Fw4;&> }
fz?Wr: I return bRemoved;
*y\tns U }
JjO/u>A3;7 kc(b;EA void VerifyWindow()
-mYI[AG) {
|u@>[*k'= for(int i=0;i<MAX_KEY;i++){
o-i.'L)X if(hCallWnd
!=NULL){ %?G.lej,x
if(!IsWindow(hCallWnd)){ s8I77._s
hCallWnd=NULL; ]O(HZD%
HotKey=0; yar IR|
HotKeyMask=0; /z- C
:k\
KeyCount--; Ko1?jPE
} u'n%BVt
} 89e.\EH
} &i}cC4i
} B>nd9Z '
l aL4ez
BOOL CHookApp::InitInstance() :Y?08/V
{ =Q0)t_z_
AFX_MANAGE_STATE(AfxGetStaticModuleState()); m?CjYqvf
hins=AfxGetInstanceHandle(); $MEbePxe
InitHotkey(); ^@w1Z{:
return CWinApp::InitInstance(); _
~$0cj<
} =ir;m
XV9'[V
int CHookApp::ExitInstance() }sNZQ89V*v
{ eDZ3SIZ
VerifyWindow(); RKZk/ly
UnInit(); gR6T]v
return CWinApp::ExitInstance(); yaGVY*M0
} .BTT*vL-
F"0jr7
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file RX|&