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:
vUvIZa
MY4cMMjp~ 一、实现方法
)g9Zw_3 [$;6LFs} 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:
pDCQ?VW <i%.bfQ/- #pragma data_seg("shareddata")
+Q}Y ?([ HHOOK hHook =NULL; //钩子句柄
mcpM<vY/H UINT nHookCount =0; //挂接的程序数目
c3Y\XzV3v static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
68+9^ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
HKb8z@;%@ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
^6Hfq^ejt static int KeyCount =0;
yFH)PQ_ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
&#w]
2~| #pragma data_seg()
N'i%9SBcg a 5:YP 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。
o[O-|XL_ F%+/j5~^ 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:
I|n<B"Q6^ @i$9c)D BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
=UM30
P/ cKey,UCHAR cMask)
go@UE2qw {
/al(=zf BOOL bAdded=FALSE;
@'/\O- for(int index=0;index<MAX_KEY;index++){
1<\@i{;xsU if(hCallWnd[index]==0){
M0S}-eXc5 hCallWnd[index]=hWnd;
pD eqBO HotKey[index]=cKey;
ZXFM_>y5 HotKeyMask[index]=cMask;
506B= bAdded=TRUE;
(XX6M[M8 KeyCount++;
T7'njaLec break;
>hJ$~4? }
|K,9EM3 }
fJH09:@^% return bAdded;
ltO:./6v }
YRfs8I^rg //删除热键
}'b3'/MJ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
*rXESw]BR {
R/Mwq#xUb BOOL bRemoved=FALSE;
?nn`ud?f for(int index=0;index<MAX_KEY;index++){
o6'I%Gs if(hCallWnd[index]==hWnd){
h*Rh:yCR> if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
*}-X
'_ hCallWnd[index]=NULL;
I_6?Q^_uZ HotKey[index]=0;
<_dyUiT$J HotKeyMask[index]=0;
Yo/U /dB bRemoved=TRUE;
\|F4@ KeyCount--;
hJ (Q^Z break;
5IOOV Yl }
`{gkL- }
lQ<2Vw#Yl }
_[<R<&jG return bRemoved;
>8"oO[U5> }
r1\c{5Wt 'nz;|6uC &BY%<h0c DLL中的钩子函数如下:
ryB^$Kh,, eB%KXPhMm LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
AE={P*g {
8V`NQS$ BOOL bProcessed=FALSE;
9TIyY`2! if(HC_ACTION==nCode)
h3Nwxj~E {
ms{:=L2$$ if((lParam&0xc0000000)==0xc0000000){// 有键松开
Kyt.[" p switch(wParam)
1XSA3;ZEc {
&Gp@,t case VK_MENU:
A[
9
@:z MaskBits&=~ALTBIT;
W2D^%;mw break;
CC0@RU case VK_CONTROL:
AON";&dLq- MaskBits&=~CTRLBIT;
HgvgO\`] break;
?l!L
)!2 case VK_SHIFT:
ig4wwd@| MaskBits&=~SHIFTBIT;
%0fF_OU break;
r Lg(J|^ default: //judge the key and send message
vIF=kKl9, break;
Sf);j0G,D }
)@09Y_9r for(int index=0;index<MAX_KEY;index++){
X^r5su? if(hCallWnd[index]==NULL)
\V
/s continue;
p(QB 5at if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
EgOAEv {
Jkzt=6WZ0 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
X6kB
R bProcessed=TRUE;
rbiNp6AdL }
|s-q+q{| }
}__g\?Yf }
R7;SZo else if((lParam&0xc000ffff)==1){ //有键按下
IfzHe8> switch(wParam)
veFl0ILd {
Gtd!Y
x case VK_MENU:
zpV@{%VSj MaskBits|=ALTBIT;
9I0/KuZd
O break;
:y==O4 case VK_CONTROL:
]sjYxe MaskBits|=CTRLBIT;
^m;dEe&@F break;
` wuA}v3! case VK_SHIFT:
\{AxDk{z# MaskBits|=SHIFTBIT;
M>D 3NY[, break;
|RDmY!9& default: //judge the key and send message
T)&J}^j break;
2.ud P }
kT@RA} for(int index=0;index<MAX_KEY;index++){
,DK |jf if(hCallWnd[index]==NULL)
;ZHKTOoK continue;
"D}PbT[V if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
a\S"d {
]:i
:QiYD SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
i>HipD,TD bProcessed=TRUE;
7Bm 18 }
/%EKq+ZP }
>^LVj[.1 }
D
M(WYL{ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
_P
0,UgZz for(int index=0;index<MAX_KEY;index++){
F,Y@ if(hCallWnd[index]==NULL)
+Mc kR continue;
-}`ES] if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
wUWSW< SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
u
'DM?mV:- //lParam的意义可看MSDN中WM_KEYDOWN部分
] as_7 }
#t:]a<3Y2 }
`2c>M\c4U }
-CfGWO#Gbx return CallNextHookEx( hHook, nCode, wParam, lParam );
Zx,R6@l }
E{kh)- AWHB^}!} 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:
e:hkWcV <MZ$ baK BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
&dF$:$'s BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Rn~FCj,- vZj^&/F$=g 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
nv1'iSEeOl oJe9H < LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
P1;T-.X~& {
g9|B-1[ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
[/hS5TG|7 {
(mz5vzyw //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
Z)EmX= SaveBmp();
6kuN) return FALSE;
&o{I9MD }
La48M'u …… //其它处理及默认处理
3p{N7/z( }
Zs<}{`- |!{Q4< jLX{$, 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%"${ywI &I:[ 'l! 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。
9 P_`IsVK 1RM;"b/ 二、编程步骤
vA@Kb3, s:lar4>kM 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";
]2(vO0~ _
vVw2HH 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
rGuhYYvK []:;8fY 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;
$T{,3;kt *6^|i} 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;
e`k6YO fL.;- 5、 添加代码,编译运行程序。
=MDir$1Z ]UKKy2r. 三、程序代码
jT"P$0sJAd ZOc1 vj ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
fiOc;d8 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
J01w\#62pQ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
7)$U>|= #if _MSC_VER > 1000
J~KWn. #pragma once
x3=W{Fv@4 #endif // _MSC_VER > 1000
GdG1e%y]z #ifndef __AFXWIN_H__
$fhrGe #error include 'stdafx.h' before including this file for PCH
8v@6 &ras@ #endif
95Bw;U3E #include "resource.h" // main symbols
1}#v<b$ class CHookApp : public CWinApp
@?iLz7SPk {
I Gv_s+O-* public:
/]"&E"X" CHookApp();
>JwdVy^ // Overrides
r@FdxsCnGM // ClassWizard generated virtual function overrides
H`q" _p: //{{AFX_VIRTUAL(CHookApp)
9 tkj:8_ public:
&?>h#H222 virtual BOOL InitInstance();
Cnd70tbD ) virtual int ExitInstance();
$'e;ScH //}}AFX_VIRTUAL
_H}y7 //{{AFX_MSG(CHookApp)
%])-+T // NOTE - the ClassWizard will add and remove member functions here.
y[[f?rxz> // DO NOT EDIT what you see in these blocks of generated code !
txQyHQ)@ //}}AFX_MSG
Z
l.}= DECLARE_MESSAGE_MAP()
DLcfOOn1I };
kf\n
LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
wVkms BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
IK5FSN]s/ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
w]]`/` BOOL InitHotkey();
d=V4,:=S BOOL UnInit();
)~xL_yW_X #endif
NCYN .@J `GOxFDB. //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
tk"L2t #include "stdafx.h"
;KJJK#j #include "hook.h"
kRs[H xI3 #include <windowsx.h>
L>+g;GJ #ifdef _DEBUG
rt$zM #define new DEBUG_NEW
11}sRu/ #undef THIS_FILE
%AW5\ EX static char THIS_FILE[] = __FILE__;
mN+~fuh #endif
j[NA3Vj1P #define MAX_KEY 100
Je_Hj9#M\d #define CTRLBIT 0x04
+#8?y
5~q #define ALTBIT 0x02
QwXM<qG* #define SHIFTBIT 0x01
[M_pf2Y #pragma data_seg("shareddata")
! P/ ]o HHOOK hHook =NULL;
!iUdej^tx UINT nHookCount =0;
b9ysxuUdS static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
MV6%~T static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
lnL&v'{ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
3GqJs static int KeyCount =0;
@+~=h{jv< static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
3S1V^C-eBx #pragma data_seg()
58zs%+F HINSTANCE hins;
~J?O ~p`& void VerifyWindow();
AE!WYE BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
LinARMPv //{{AFX_MSG_MAP(CHookApp)
PbxuD*LQ. // NOTE - the ClassWizard will add and remove mapping macros here.
'&Ox,i]t // DO NOT EDIT what you see in these blocks of generated code!
z"o;|T: //}}AFX_MSG_MAP
b7R#tT END_MESSAGE_MAP()
C>7Mx{ !H fHvQ 9*T CHookApp::CHookApp()
f^](D'L?D {
WS9n.opl} // TODO: add construction code here,
B[ae<V0k // Place all significant initialization in InitInstance
$UW!tg*U& }
heoOOP(# SFoF]U09 CHookApp theApp;
vM~/|)^0sW LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
i0/gyK {
RtH[OZu(8 BOOL bProcessed=FALSE;
%(;jx if(HC_ACTION==nCode)
C&D]!ZvF {
W~p^AHco` if((lParam&0xc0000000)==0xc0000000){// Key up
Tj*o [2mD switch(wParam)
T[a1S ?_*T {
ju0]~, case VK_MENU:
%8/Gsu; MaskBits&=~ALTBIT;
% \N.m/5 break;
//@_`. case VK_CONTROL:
'j#oMA{0 MaskBits&=~CTRLBIT;
toPA@V break;
hor ok:{ case VK_SHIFT:
Djx9TBZ5 MaskBits&=~SHIFTBIT;
Noz+\O\ break;
/'
L20aN2 default: //judge the key and send message
[?Y u3E\ break;
OdgfvHDgW }
p9R`hgx for(int index=0;index<MAX_KEY;index++){
]n?a h if(hCallWnd[index]==NULL)
D}"\nCz}y& continue;
j)Kk:BFFY if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
a1ZGMQq! {
G39H@@ *O0 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
QnZR bProcessed=TRUE;
^q"p8 }
[ /*$?PXt }
~cSC-|$^& }
!Y=s_)X else if((lParam&0xc000ffff)==1){ //Key down
o;FjpZ switch(wParam)
:eS7"EG{3 {
Zm%}AzM case VK_MENU:
O8SX#,3^} MaskBits|=ALTBIT;
;1S{xd*^N break;
]w%7/N0R case VK_CONTROL:
c}Jy'F7&f MaskBits|=CTRLBIT;
Gcg`Knr break;
N\H{p%8 case VK_SHIFT:
\ ^EjE MaskBits|=SHIFTBIT;
0LoA-c<Ay break;
M7yJ2u <Ty default: //judge the key and send message
M<7<L break;
Bx
E1Ky8@A }
l,h#RTfry for(int index=0;index<MAX_KEY;index++)
I OF~V)8k= {
HG@!J>YaD if(hCallWnd[index]==NULL)
'\1%%F7 continue;
Q9K
Gf; if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
R.A}tV=j# {
6BW-AZc SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
r d]HoFE bProcessed=TRUE;
}n=Tw92g }
.)|jBC8|} }
Y8.0R-:ZAN }
$>/J8iB if(!bProcessed){
%P_\7YBC> for(int index=0;index<MAX_KEY;index++){
'Twi
@I if(hCallWnd[index]==NULL)
C,]Q/6'> continue;
qTqvEa^X` if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
N<Bi.\XC SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
] 5P{* }
'BAe>r_Pn }
po=*%Zs*T }
7`X"B*`~b return CallNextHookEx( hHook, nCode, wParam, lParam );
F
xFK }
K!|=)G3.` p: sn>Y BOOL InitHotkey()
;oh88,*' {
Q
C~~ if(hHook!=NULL){
@pytHN8( $ nHookCount++;
7 bsW7;C return TRUE;
=6 }
z &<Rx[ else
_?kf9 . hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
Tj0eW(<!s if(hHook!=NULL)
Zu%_kpW nHookCount++;
&o4L;A#& return (hHook!=NULL);
_I{&5V~z }
b%$S6. BOOL UnInit()
H/)= {
A
,LAA$ if(nHookCount>1){
dmlh;Z nHookCount--;
fbw{)SZ return TRUE;
42z9N\ f }
?N11R?8 BOOL unhooked = UnhookWindowsHookEx(hHook);
7MGc+M(p if(unhooked==TRUE){
BC@"WlD nHookCount=0;
aE,x>I 7 D hHook=NULL;
/f%u_ 8pV% }
P]y2W#Rs return unhooked;
J)jiI> }
WK;p[u?~xi {GWcw<g.B BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
v{% /aw {
'2# 0UdG BOOL bAdded=FALSE;
=[1W.Zt for(int index=0;index<MAX_KEY;index++){
c
|C12b[ if(hCallWnd[index]==0){
KOF! a hCallWnd[index]=hWnd;
VKik8)/. HotKey[index]=cKey;
,nHz~Xi1t HotKeyMask[index]=cMask;
+nJ}+|@K bAdded=TRUE;
/E]4N=T KeyCount++;
ew`R=<mZ,7 break;
"A/kL@ -C }
,R^Pk6m> }
saRB~[6I return bAdded;
H>DJ-lG( }
//LXbP3/ ;V@}
oD+ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
`gss(o1} {
{ @-Q1 BOOL bRemoved=FALSE;
:A[bqRqe for(int index=0;index<MAX_KEY;index++){
ww\/$ | if(hCallWnd[index]==hWnd){
k*!J,/=k if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
B=Zo0p^ hCallWnd[index]=NULL;
b7>;UX HotKey[index]=0;
2>EIDRLJ- HotKeyMask[index]=0;
~{5%~8h.0r bRemoved=TRUE;
Fa/i./V2 KeyCount--;
efbt\j6@%2 break;
vG\Wr.h0!= }
gdT^QM:y4$ }
x_@ev- }
10[~ki-1; return bRemoved;
$C[YqZO }
a,j!B
hu eQ9x l void VerifyWindow()
U|
N`X54 {
6B+
@76w H for(int i=0;i<MAX_KEY;i++){
-%t0'cKn, if(hCallWnd
!=NULL){ n[iil$VKh
if(!IsWindow(hCallWnd)){ 5 ;|9bWH
hCallWnd=NULL; 1qQgAhoY
HotKey=0; hD$U8~zK
HotKeyMask=0; )(ma
KeyCount--; 3BSeZ:j7
} s-C.+9
} M?\)&2f[Z
} F~DG:x~
} Ffhbs D
uj:w^t ][
BOOL CHookApp::InitInstance() Y]Fq)-
{ !^m5by
AFX_MANAGE_STATE(AfxGetStaticModuleState()); +s S*EvF
hins=AfxGetInstanceHandle(); K^w9@&