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:
U g}8y8
;&Bna#~B 一、实现方法
><NI'q*cQ <NG/i i= 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:
+0XL5('2 +yf(Rs)! #pragma data_seg("shareddata")
GilQtd3\ HHOOK hHook =NULL; //钩子句柄
A~Z6jK UINT nHookCount =0; //挂接的程序数目
1,"I= static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
~+O `9& static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
m'cz5mcD static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
E X%6''ys static int KeyCount =0;
`$s)X$W? static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
kSbO[)p #pragma data_seg()
Jd5\&ma k"xGA*B| 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。
{=UFk-$= @$qOW 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:
d_Q*$Iz)3 #zON_[+s9 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
0QMTIAW6h cKey,UCHAR cMask)
d<Ggw#}:m {
t})lr\ BOOL bAdded=FALSE;
EL^8zyg%% for(int index=0;index<MAX_KEY;index++){
))7LE|1l if(hCallWnd[index]==0){
eV"!/A2:N5 hCallWnd[index]=hWnd;
'X =p7 d|' HotKey[index]=cKey;
)~ 0}Et l HotKeyMask[index]=cMask;
V0K16#}1gM bAdded=TRUE;
lVPOYl% KeyCount++;
^SZw`] break;
:e*DTVv8 }
wfgqgPo!v }
ypx: )e"/ return bAdded;
lnS(&`oh\= }
l)4O . * //删除热键
qv[[Q[RK-5 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
qnB<k,8T {
N]NF\7( BOOL bRemoved=FALSE;
NXpmT4 for(int index=0;index<MAX_KEY;index++){
2{bhA5L if(hCallWnd[index]==hWnd){
bS.s?a if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
33Jd!orXU hCallWnd[index]=NULL;
JVtQ,oZ HotKey[index]=0;
=#qZ3 Qz_ HotKeyMask[index]=0;
L!t@-5~
bRemoved=TRUE;
,CP5~4u KeyCount--;
zh\p break;
:0$a.8Y\++ }
tz26=8 }
Ck\7F?S }
RK[D_SmS return bRemoved;
F^QQ0h]2 }
{~SaRB2<' E<>*(x/\e A{# Nwd> DLL中的钩子函数如下:
"(v%1tGk iPq &Y* LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
hoa7 {
H{l) BOOL bProcessed=FALSE;
^$v3eKA if(HC_ACTION==nCode)
rLU'*} {
bB!#:j>(v if((lParam&0xc0000000)==0xc0000000){// 有键松开
8)N@qUV switch(wParam)
.N,&Uv- {
"-31'R- case VK_MENU:
T .REq4< MaskBits&=~ALTBIT;
M|q~6oM break;
#] CFA9z case VK_CONTROL:
+Y}V3(w9X MaskBits&=~CTRLBIT;
`ltN,?/ break;
<Mx0\b! case VK_SHIFT:
[}OgSP9i MaskBits&=~SHIFTBIT;
:_ROJ break;
?+~cA^-3T default: //judge the key and send message
O}Hf62" break;
fH\X }
$=B8qZ+ for(int index=0;index<MAX_KEY;index++){
|Os6V<u" if(hCallWnd[index]==NULL)
!d,8kG continue;
Qck|#tc if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
n`ViTwd]MQ {
:IMdN}(L SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
1|{bDlmt bProcessed=TRUE;
"5C`,4s }
?-MP_9!JK }
*4S-z&,.c }
qnM|w~G else if((lParam&0xc000ffff)==1){ //有键按下
:`\)
P, switch(wParam)
J NVr {
lhH`dG D case VK_MENU:
a2w T6jY MaskBits|=ALTBIT;
Ml?~
|_ break;
j'?7D0> case VK_CONTROL:
YAVy9$N- MaskBits|=CTRLBIT;
W=JAq%yd< break;
!8
-oR6/$% case VK_SHIFT:
4jNG^@O MaskBits|=SHIFTBIT;
=PkO!Mm8 break;
POAw M default: //judge the key and send message
H#i{?RM@l break;
!}f1`/ }
g13 rx%- for(int index=0;index<MAX_KEY;index++){
mO*^1 if(hCallWnd[index]==NULL)
ehNzDr\s continue;
tz^/J=)" if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Y ^KTkS0D {
:i~W
}r SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
eS+g| $cW bProcessed=TRUE;
~g#r6pzN- }
4dawg8K`9 }
#3$\Iu }
izgp*M, if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
@{hd{>K* for(int index=0;index<MAX_KEY;index++){
Bc7V)YK if(hCallWnd[index]==NULL)
G7GZDi continue;
P>i%7:OMZA if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
P 1XK*GZ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
m<rhIq //lParam的意义可看MSDN中WM_KEYDOWN部分
NGC,lv }
'3 33Ctxy }
1x)ZB~L }
%" D%: return CallNextHookEx( hHook, nCode, wParam, lParam );
gF?[rqz{ }
N8toxRu TlZT1H 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:
=( v^5 j;b42G~p BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
p;T{i._iL BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
h!rM^ +Y"r71|A6+ 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:
q h/F }`(N:p LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
;0rGiWC# {
'e)^m}:?D if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
j/`94'Y {
k%s_0
@ //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
<BFQ: SaveBmp();
M`YWn ; return FALSE;
>Fio;cn? }
54lu2gD' …… //其它处理及默认处理
mw$r$C{ }
aNcd`
$0 S$TmZk= fyTAou6hI 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。
,DdB^Ig<r E`int?C! 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。
W>_]dPB S/ ?eH&'m}- 二、编程步骤
"@R>J?Cc+ ) J]9 lW&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";
}KUd7[s T>TWU: 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
ca i<,3H K 0gI): 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;
z>sbr<doa L`f^y;Y. 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;
[B@'kwD\l +#U|skl 5、 添加代码,编译运行程序。
&Z(K6U#. **9x?s 三、程序代码
n0Y+b[+wj _Zk{! ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
NBl+_/2'w #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
,.eWQK~ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
1b=lpw1} #if _MSC_VER > 1000
oSiMpQu08 #pragma once
|4$M]M f0 #endif // _MSC_VER > 1000
E_Z{6&r #ifndef __AFXWIN_H__
C~fjWz' V #error include 'stdafx.h' before including this file for PCH
O~j> ? #endif
ojYbR<jn9 #include "resource.h" // main symbols
'z76Sa class CHookApp : public CWinApp
sn7AR88M; {
f}g\D#`]/ public:
R_M?dEtE> CHookApp();
b0iSn#$ // Overrides
S$KFf=0 // ClassWizard generated virtual function overrides
kEwaT$ //{{AFX_VIRTUAL(CHookApp)
~wg:!VWA) public:
X%yO5c\l2 virtual BOOL InitInstance();
]7-&V-Ct* virtual int ExitInstance();
Qt_dEl //}}AFX_VIRTUAL
coYij //{{AFX_MSG(CHookApp)
:0Z^uuk`gq // NOTE - the ClassWizard will add and remove member functions here.
?X@fKAj // DO NOT EDIT what you see in these blocks of generated code !
(c0A.L)
//}}AFX_MSG
;iDPn2?6?x DECLARE_MESSAGE_MAP()
:#dE:L;T };
2,ECYie^ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
)`^p%k BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
6'\6OsH BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
%%(R@kh9 BOOL InitHotkey();
^N8)]F, BOOL UnInit();
&zs'/xv] #endif
DNGvpKY@ ~y=T5wt //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Kw#so; e #include "stdafx.h"
P[s8JDqu #include "hook.h"
+P.+_7+: #include <windowsx.h>
^C2\`jLMY #ifdef _DEBUG
U,nEbKJgk #define new DEBUG_NEW
KWLbD# #undef THIS_FILE
X,9 M"E
2 static char THIS_FILE[] = __FILE__;
v<Bynd- #endif
ECv)v #define MAX_KEY 100
l5L.5$N #define CTRLBIT 0x04
E=){K #define ALTBIT 0x02
UH3sH
t #define SHIFTBIT 0x01
>2#8B #pragma data_seg("shareddata")
^CwR!I.D}4 HHOOK hHook =NULL;
wAnb
Di{W UINT nHookCount =0;
!w&kyW?e static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
zYl#4O`=c static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
C8F 7bG8c static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
sz9L8f2 static int KeyCount =0;
CI3XzH\IX* static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
Z7 E #pragma data_seg()
'X shmZ0& HINSTANCE hins;
qzb<J=FAU void VerifyWindow();
DTWD|M BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
_X@v/sAy //{{AFX_MSG_MAP(CHookApp)
cQ9q;r`% // NOTE - the ClassWizard will add and remove mapping macros here.
{Zp\^/ // DO NOT EDIT what you see in these blocks of generated code!
asJ)4ema //}}AFX_MSG_MAP
L(X6-M: END_MESSAGE_MAP()
KK@.~'d N!*_La=TuH CHookApp::CHookApp()
`^lYw:xA {
S_~z-`;h! // TODO: add construction code here,
qCv20#!"| // Place all significant initialization in InitInstance
:;t
#\%L/ }
uc|45Zxt xe/( CHookApp theApp;
{rcnM7 S1L LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
=y=cW1TG {
}NsUnbxT BOOL bProcessed=FALSE;
4H@Wc^K if(HC_ACTION==nCode)
|HZTN" {
pmX#E if((lParam&0xc0000000)==0xc0000000){// Key up
9c JH" switch(wParam)
&y<ZE {
A&>.74}p case VK_MENU:
V2N_8)s9W MaskBits&=~ALTBIT;
PfkrOsV/m break;
28
3H case VK_CONTROL:
~F1:N>>_Cf MaskBits&=~CTRLBIT;
j(~ *'&|( break;
dDnf^7q/ case VK_SHIFT:
[TNj;o5J MaskBits&=~SHIFTBIT;
s: 3z'4oX break;
6m6zA/ default: //judge the key and send message
<8,cuX\ break;
ne^imht }
_V\Bp=9W for(int index=0;index<MAX_KEY;index++){
dg^L= if(hCallWnd[index]==NULL)
je]}R>[r5 continue;
iDf,e Kk$' if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
u :F~K {
O@YTAT&d# SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Z{H5oUk bProcessed=TRUE;
bGorH=pb5R }
t='# |'); }
;[a|9TPR }
r7Ya\0gU else if((lParam&0xc000ffff)==1){ //Key down
GtwT switch(wParam)
t!IaUW {
hHDOWHWE case VK_MENU:
c2K:FdB MaskBits|=ALTBIT;
g(#f:" break;
}MlwC;ot case VK_CONTROL:
HI@syFaJM MaskBits|=CTRLBIT;
DLCkM*' break;
b"TjGE case VK_SHIFT:
{aM<{_v MaskBits|=SHIFTBIT;
\lSU break;
_!|/
;Nk default: //judge the key and send message
pJ
?~fp break;
>"Q@bQ:e }
t+Op@*#% for(int index=0;index<MAX_KEY;index++)
}6 K^`! {
~@kU3ZGJZ if(hCallWnd[index]==NULL)
oHs2L-G continue;
.$#rV?7 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
,k G>?4 {
mg,j:, SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
n#iwb0- bProcessed=TRUE;
1 `KN]Nt }
D0BI5q }
5y?-fT]X }
&hk-1y9QS if(!bProcessed){
[}fv dW for(int index=0;index<MAX_KEY;index++){
%8~3M75$ if(hCallWnd[index]==NULL)
Q~Z=(rP20 continue;
O2"gj"D if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
2./3 \n2 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
+Y+Y6Ac[} }
){Ob,LEU& }
"kc/J*u-3 }
M|] "W return CallNextHookEx( hHook, nCode, wParam, lParam );
Ka`=WeJ| }
Yf[Qtmh]I M5x U9]B BOOL InitHotkey()
>fIk;6<{ {
mJM_2Ab if(hHook!=NULL){
B7z -7&TE nHookCount++;
^H6<Km
l/V return TRUE;
V=1Bo~ }
hxS 6:5Uc else
R-P-i0~ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
K+6e?5t if(hHook!=NULL)
qL94SW; nHookCount++;
kQ return (hHook!=NULL);
+\r+n~w }
Zo{$ BOOL UnInit()
}E_#k]#* {
V"!G2& if(nHookCount>1){
U#1bp}y nHookCount--;
3 LdQ]S return TRUE;
|{@FMxn|q }
B*gdgM*` BOOL unhooked = UnhookWindowsHookEx(hHook);
O=9-Qv| if(unhooked==TRUE){
%K]euEqs nHookCount=0;
pc?>cs8 hHook=NULL;
sp*Vqd }
03j]d&P%d
return unhooked;
~l2aNVv; }
V:G>G'Eh0 t
R6
+G BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
JBnKK {
~g7l8H67 BOOL bAdded=FALSE;
>*wtbkU for(int index=0;index<MAX_KEY;index++){
(@#M!' if(hCallWnd[index]==0){
LjU'z# hCallWnd[index]=hWnd;
7w1wr)qSB HotKey[index]=cKey;
nW|wY. HotKeyMask[index]=cMask;
boo
}u bAdded=TRUE;
{$ep7;'d KeyCount++;
# M!!CX*k break;
Iz[@^IUx= }
jM:Y'l] }
mYU9
trHV return bAdded;
|]Qg7m,O }
_uJ"m8Tl a[2vjFf#C BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
+S))3 5N[ {
+<prgP`v BOOL bRemoved=FALSE;
1xc~`~ for(int index=0;index<MAX_KEY;index++){
i%6; if(hCallWnd[index]==hWnd){
SIKOFs if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
xTGxvGv8 hCallWnd[index]=NULL;
{3!E4"p HotKey[index]=0;
a5G/[[cwTV HotKeyMask[index]=0;
G/v/+oX bRemoved=TRUE;
J6<rX[
yZe KeyCount--;
ltFq/M break;
(8ht*b.5K }
(|d34DOJ }
{vo +gRYYv }
@zgdq return bRemoved;
SwU\
q]^|Z }
uf&N[M ^_ojR4 void VerifyWindow()
HV/c c" {
dik9 >*"|o for(int i=0;i<MAX_KEY;i++){
I=;+n- if(hCallWnd
!=NULL){ ?<*-j4v
if(!IsWindow(hCallWnd)){ 2y%,p{="
hCallWnd=NULL; |+$%kJR=
HotKey=0; 1jX3ey~
HotKeyMask=0; 6;
Y0a4Ax
KeyCount--; S\CRG>
} -n0C4 kZ2o
} f7I{WfZ\P
} 5E0eyW
}
4^<