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:
hp7ni1V
(KvN#d 1\ 一、实现方法
%Zfh6Bl\X U3M;{_g 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:
5ff5M=M 1} _<q k9 #pragma data_seg("shareddata")
1?"Zrd HHOOK hHook =NULL; //钩子句柄
1xsJz^%V UINT nHookCount =0; //挂接的程序数目
;<cCT!A static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
"}[ ]R static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
OB+ cE4$ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
|1<B(iB'{/ static int KeyCount =0;
>h9~
/ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
ljg6uz1v% #pragma data_seg()
d;3f80Kd* ^"uD:f) 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。
n"~K",~P l r~>!O 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@6*d.+e u2':~h?l BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
c*(=Glzn cKey,UCHAR cMask)
rc`I l{~k {
!0Ak)Q]e' BOOL bAdded=FALSE;
A-^B?E for(int index=0;index<MAX_KEY;index++){
hsK(09:J if(hCallWnd[index]==0){
E1A5<^t hCallWnd[index]=hWnd;
O|9Nl*rXz HotKey[index]=cKey;
q}E'x/s2m HotKeyMask[index]=cMask;
UpiZd/K bAdded=TRUE;
IG%x(\V-e KeyCount++;
Sl
\EPKZD break;
FELW?Q?k }
,&@FToR }
h,/3} return bAdded;
a94nB }
Jcp=<z*0 //删除热键
2 0A:,pMb BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
p-z!i +
{
(f*r BOOL bRemoved=FALSE;
AO7X-, for(int index=0;index<MAX_KEY;index++){
7 lq$PsC if(hCallWnd[index]==hWnd){
J|z ' <W if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
?Qpi(Czbpq hCallWnd[index]=NULL;
%yR80mn8 HotKey[index]=0;
@ L/i HotKeyMask[index]=0;
-H5-6w$ bRemoved=TRUE;
3m~3l d KeyCount--;
*JWPt(bnI break;
kWbY&]ZO }
(5 RZLRn }
)R@Y$*fm }
)1)&fN41i# return bRemoved;
f\:I1y }
Z#GR)jb+ L'"od;(6R 0U2dNLc DLL中的钩子函数如下:
mm
|* ])zpx- LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Wx8cK= {
LH~
t5 BOOL bProcessed=FALSE;
a=[|"J<M if(HC_ACTION==nCode)
1u*
(=! {
On@p5YRwW if((lParam&0xc0000000)==0xc0000000){// 有键松开
^<aj~0v switch(wParam)
Ds8x9v)^ {
%VrMlG4hx case VK_MENU:
2T"[$iH!7 MaskBits&=~ALTBIT;
PJh97%7 break;
`KP}pi\ case VK_CONTROL:
sJ_3tjs) MaskBits&=~CTRLBIT;
kPnuU! break;
]/mRMm9"3h case VK_SHIFT:
Yp$@i20 MaskBits&=~SHIFTBIT;
w#sP5qKv8 break;
S~ y.>X3"P default: //judge the key and send message
t.7_7`bin~ break;
$bk_%R}s }
A&Q!W)= for(int index=0;index<MAX_KEY;index++){
Ez>!%Hpn\ if(hCallWnd[index]==NULL)
sgB|2cj;j continue;
l-'\E6grdH if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
?&b"/sRS {
z)*\njYe SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
1| xKb(_l bProcessed=TRUE;
OJLyqncw }
A+hT2Ew@t} }
ksqb& ux6 }
fp"GdkO#}i else if((lParam&0xc000ffff)==1){ //有键按下
R1:7]z0B switch(wParam)
DEenvS`,P {
>LFj@YW_) case VK_MENU:
Nw3IDy~T MaskBits|=ALTBIT;
i32S(3se break;
rT{2 case VK_CONTROL:
CyJZip MaskBits|=CTRLBIT;
T"Nnl(cO_ break;
R9Y{kk0M case VK_SHIFT:
JaJyH%+$! MaskBits|=SHIFTBIT;
&([yI>% break;
z|N*Gs>, default: //judge the key and send message
CDFkH break;
p?+;[!: }
CWE^:kr6 for(int index=0;index<MAX_KEY;index++){
0h"uJco, if(hCallWnd[index]==NULL)
${7s"IX continue;
71HrpTl1fw if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
WQY\R!+ {
'/F~vSQsR SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
o@|kq1m8 bProcessed=TRUE;
!p70g0+ }
xb^M33-y }
}ev+WIERQV }
(/J %Huy if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
zS}!87r) for(int index=0;index<MAX_KEY;index++){
@<p9O0 if(hCallWnd[index]==NULL)
Qlhm:[ continue;
Eqt>_n8 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
2!Pwg0%2 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
2{)<Df@ //lParam的意义可看MSDN中WM_KEYDOWN部分
V5d|Lpm }
R
#m1Aa }
FHZQyO<| }
<Ow+LJWQK return CallNextHookEx( hHook, nCode, wParam, lParam );
h&IF?h }
9!vimu) #r80FVwiD 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
G4,BcCPQ
`AELe_ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
?Q}3X-xy BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
<``krPi DOWZhD 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
Z
,98 :J6FI6 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
}+
TA+; {
sQa9M if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
)Z@hk]@?_[ {
fH;lh- //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
Oat
#% SaveBmp();
%lN4"jtx return FALSE;
jD_B&MQz }
IS }U2d,W …… //其它处理及默认处理
O:[@?l }
\1#!%I=. AKKVd%
P( 3+:uV 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
ltXGm)+ [[8h*[: 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
wEbO|S+K1 \&%y4=y<sE 二、编程步骤
v!rOT/I H?dEgubg7] 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
ZvW&%*k= O9MBQNwjA 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
VV=6v;u` ]hA]o7k 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
LfG$?<}hR R~XNF/QMl 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;
I$Fr8R$ ~2?UEv6 5、 添加代码,编译运行程序。
&Zm1(k6&K /)xQ# yfX 三、程序代码
0:k
MnHn\ 0XrOOYmx ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
Hbz,3{o5 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
L~L]MC& #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
M%FKg/ #if _MSC_VER > 1000
3x~AaC.j #pragma once
("j*!Dsd #endif // _MSC_VER > 1000
[fXC ;c1 #ifndef __AFXWIN_H__
#Xd#Ncj #error include 'stdafx.h' before including this file for PCH
=`BPGfCb #endif
Ix|^c268o< #include "resource.h" // main symbols
~dj4Q
eu class CHookApp : public CWinApp
.2STBh.; {
jQ\/R~)O public:
B?<Z(d7 CHookApp();
OL$^7FB // Overrides
3ocRq
%%K // ClassWizard generated virtual function overrides
+N!!Z2 //{{AFX_VIRTUAL(CHookApp)
%p.hwgvnp public:
O7tL,)Vv virtual BOOL InitInstance();
-` e`U%n virtual int ExitInstance();
[$(/H; //}}AFX_VIRTUAL
{Ng HH]]O //{{AFX_MSG(CHookApp)
ZlsdO.G // NOTE - the ClassWizard will add and remove member functions here.
s2\6\8Ipn // DO NOT EDIT what you see in these blocks of generated code !
H3"D$Nv //}}AFX_MSG
v_ W03\ DECLARE_MESSAGE_MAP()
Y@M
l}43 };
"]{"4qV1= LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
8\ WOss)al BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
cK+y3`.0 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
r=pb7=M#LN BOOL InitHotkey();
&>o?0A6 BOOL UnInit();
"J6aU #endif
lIF*$#`oh* {uMqd-Uu //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
FUU/=)^P$ #include "stdafx.h"
J*CfG;Y: #include "hook.h"
@](\cT64i3 #include <windowsx.h>
r<L>~S>yb #ifdef _DEBUG
7Ke#sW.HN #define new DEBUG_NEW
Ty>g:#bogI #undef THIS_FILE
V{G9E static char THIS_FILE[] = __FILE__;
4 jeUYkJUM #endif
Pxm~2PAm #define MAX_KEY 100
i#y3QCNqf^ #define CTRLBIT 0x04
6J%+pt[tu #define ALTBIT 0x02
j{a3AEmps #define SHIFTBIT 0x01
iVGc\6+' #pragma data_seg("shareddata")
k/ ZuFTN HHOOK hHook =NULL;
9d!}]+"d42 UINT nHookCount =0;
#T8$NZA static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
4$!iw3N( static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
5&*B2ZBzH static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
6M758K6v static int KeyCount =0;
)<1}`9G static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
|K6hY-uC #pragma data_seg()
y:+s*x6Vg HINSTANCE hins;
s%R'c_cGZ void VerifyWindow();
~h*p A8^L BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
U1^R+ *yp //{{AFX_MSG_MAP(CHookApp)
`L=$,7` // NOTE - the ClassWizard will add and remove mapping macros here.
S4Vv _k-&
// DO NOT EDIT what you see in these blocks of generated code!
sZhl.[&zo //}}AFX_MSG_MAP
QWBQ0#L END_MESSAGE_MAP()
\aO.LwYm;: ]xIfgSq CHookApp::CHookApp()
[#R<Z+c {
NCM&6<_ // TODO: add construction code here,
:Gz# 4k // Place all significant initialization in InitInstance
r?= 7#/] }
ly]n2RK ~|~j01# CHookApp theApp;
/M "E5 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
'{:Yg3K {
MrA&xM BOOL bProcessed=FALSE;
!*gTC1bvB if(HC_ACTION==nCode)
e
r;3TG~ {
88ydAx#P if((lParam&0xc0000000)==0xc0000000){// Key up
^L<*ggw switch(wParam)
IFY,j8~q {
S qQqG3F case VK_MENU:
sm>Hkci% MaskBits&=~ALTBIT;
k(;c<Z{?1
break;
^f,('0p-> case VK_CONTROL:
P2Ja*!K] MaskBits&=~CTRLBIT;
vK\;CSk
break;
y[l19eU case VK_SHIFT:
RZ[r XV5 MaskBits&=~SHIFTBIT;
cKX6pG break;
1Bz'$u;
default: //judge the key and send message
,{{uRs/ break;
F W # S.< }
]{[VTjC7rY for(int index=0;index<MAX_KEY;index++){
:>[;XT< if(hCallWnd[index]==NULL)
5)yQrS !{: continue;
}hFjl4`xa if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
4{\h53j$ {
z.[ Ok SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
$[Fh|%\ bProcessed=TRUE;
ntSPHK|' }
sS $- PX
C }
{ [4Y(l1 }
;6} *0V_!k else if((lParam&0xc000ffff)==1){ //Key down
|j
i}LWcD switch(wParam)
kgz2/, {
?6
"F.\O@ case VK_MENU:
%Iv0<oU MaskBits|=ALTBIT;
s.rS06x break;
mdOF0b%-] case VK_CONTROL:
'H`_Z e< MaskBits|=CTRLBIT;
9zkR)C break;
y\Z-x case VK_SHIFT:
8fdK|l w MaskBits|=SHIFTBIT;
%&"_=Lc break;
1!/
U#d" default: //judge the key and send message
AX%9k break;
+mP3y~|-j }
BcT|TX+ct for(int index=0;index<MAX_KEY;index++)
1Ly?XNS {
T!hU37g h? if(hCallWnd[index]==NULL)
2f]9I1{ continue;
NDRk%_Eu( if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
O329Bkg {
A]{8= SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
&Sc}3UI/F bProcessed=TRUE;
MWCP/~>a2 }
C<6IiF[>% }
3Nh;^ }
VYhZ0;' ' if(!bProcessed){
{nbD5 ? for(int index=0;index<MAX_KEY;index++){
EYUr.#: if(hCallWnd[index]==NULL)
,7pO-:*g continue;
1GW=QbO 6 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
'8>#`Yba SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
T"Wq: }
)*^PMf }
4kA/W0 VG }
Lvc*L6 return CallNextHookEx( hHook, nCode, wParam, lParam );
0=s+bo1 }
z1LATy cJm!3X BOOL InitHotkey()
eR8qO"%2: {
8*)zoT*A if(hHook!=NULL){
$Tq-<FbM) nHookCount++;
y-"*[5{W return TRUE;
Gr#p QE2; }
u:N/aaU= else
^G#=>&, hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
%.b)%= if(hHook!=NULL)
;=Bf&hY& nHookCount++;
-Tk~c1I#` return (hHook!=NULL);
;2}0Hr'| }
6[c
LbT0 BOOL UnInit()
$+ZO{
( {
tGD$cBE if(nHookCount>1){
0ldde&!p nHookCount--;
g?i_10Xlp return TRUE;
`a2Oj@jP }
C>@~W(IE BOOL unhooked = UnhookWindowsHookEx(hHook);
g=[ F W@z if(unhooked==TRUE){
qrNW\ME nHookCount=0;
(^9q7)n hHook=NULL;
^#S }
S]1+tj return unhooked;
[8SW0wsk }
cCU'~ OR( )D~:n BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
}<&g1x'pa {
Qkk~{OuC BOOL bAdded=FALSE;
:H\6wJ for(int index=0;index<MAX_KEY;index++){
z0HCmj9T if(hCallWnd[index]==0){
Os8]iNvW\ hCallWnd[index]=hWnd;
8R:H{)o~s} HotKey[index]=cKey;
r#]gAG4t\
HotKeyMask[index]=cMask;
uHQJ& bAdded=TRUE;
42Vy#t/HC KeyCount++;
*s?&)][ break;
8{JTR|yB }
:
Ot\l }
h.4;-& return bAdded;
oRy?Dx+H }
& HphE2 h dlK#V) BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
%o#D" {
X\
\\RCp BOOL bRemoved=FALSE;
N(}7M~m> for(int index=0;index<MAX_KEY;index++){
0wZLkU_( if(hCallWnd[index]==hWnd){
?GD{}f33 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ozkN&0 hCallWnd[index]=NULL;
rgIJ]vmy<H HotKey[index]=0;
R`ZU'| HotKeyMask[index]=0;
< W/-[ M bRemoved=TRUE;
F^T7u?^) KeyCount--;
J`} /+WN 7 break;
68)z`JI|<) }
(LRv c!`" }
b\gl9"X }
'|4/aHU return bRemoved;
TR{8A^XhE8 }
\#2,1W@ ?_W "=WpC void VerifyWindow()
D}cq_|mmn[ {
G5=(3 V% for(int i=0;i<MAX_KEY;i++){
1(hgSf1WH if(hCallWnd
!=NULL){ qJ"dkT*
if(!IsWindow(hCallWnd)){ ^67P(h
hCallWnd=NULL; $NG}YOP)@
HotKey=0; `z5j
HotKeyMask=0; BIbcm,YQ
KeyCount--; uTP=kgYqJ
} jDgiH}
} ^bL.|vB
} eiP>?8
} )@1_Dm@0b
pwd7I
BOOL CHookApp::InitInstance() wm*`
{ kZ`60X%wE
AFX_MANAGE_STATE(AfxGetStaticModuleState()); b
|m$ W
hins=AfxGetInstanceHandle(); 8DLR
InitHotkey(); U@m<
return CWinApp::InitInstance(); \~jt7 Q
} v]U[7 j
>0@X^o
int CHookApp::ExitInstance() "H%TOk7l
{ CL9p/PJ%e
VerifyWindow(); evg i\"
UnInit(); z~o%U&DO}
return CWinApp::ExitInstance(); AZl|;
y
} >\}2("bv
lJKhP
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file N1P[&lR
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) k@4]s_2
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ `x6 i5mp
#if _MSC_VER > 1000 N<