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:
C n.x:I@r
;mSJZYnT 一、实现方法
OFn#C! _e$T'*q 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
5^C.}/#>F gJ?Vk<hp #pragma data_seg("shareddata")
TSUT3'&~p HHOOK hHook =NULL; //钩子句柄
Mcqym8,q|3 UINT nHookCount =0; //挂接的程序数目
n0opb [ ? static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
E\vW>g*W static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
?K=
X[ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
7(B"3qF8| static int KeyCount =0;
{qb2!}FQ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
L]{1@~E:q #pragma data_seg()
-}9># <v 8'o6: 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
L[O.]2 ObSRd$M 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:
/Gvd5 hYSf;cG}A BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
>rid3~ cKey,UCHAR cMask)
y28 e=i {
MT{ovDA]. BOOL bAdded=FALSE;
hv#|dI=kZR for(int index=0;index<MAX_KEY;index++){
lFbf9s:$B if(hCallWnd[index]==0){
`R,g_{Mj hCallWnd[index]=hWnd;
Fm4)|5 HotKey[index]=cKey;
l1eF&wNC HotKeyMask[index]=cMask;
% jSB9 bAdded=TRUE;
Wph@LRB] KeyCount++;
I6rB_~]h break;
cCO2w2A[* }
z65Q"A }
H1-eMDe return bAdded;
Uq^-km#a }
cA{7*=G? //删除热键
l9#@4Os BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
bL0>ul" {
l'twy$V4|~ BOOL bRemoved=FALSE;
~ ^*;#[< for(int index=0;index<MAX_KEY;index++){
][ 1
iKT if(hCallWnd[index]==hWnd){
]La~Bh6;m if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Qz`v0"'w hCallWnd[index]=NULL;
B3'-: HotKey[index]=0;
Eh&-b6: HotKeyMask[index]=0;
=H;F{J" bRemoved=TRUE;
dZ`c KeyCount--;
"I0F"nQ break;
[(*? }
T&+y~c[au }
D8f4X
w}= }
E-Y4TBZ* return bRemoved;
RiiwsnjC }
lw=!v%L `&URd&ouJD \EW<;xq DLL中的钩子函数如下:
;S+]Z!5LT \k.W
F|~ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
qyL!>kZr@ {
i)=
\-C BOOL bProcessed=FALSE;
3gs!ojG if(HC_ACTION==nCode)
qh#?a' {
JS^!XB'! if((lParam&0xc0000000)==0xc0000000){// 有键松开
%/w%A:y#& switch(wParam)
*;[g Ga~ {
cf,^7,-`" case VK_MENU:
::sk) MaskBits&=~ALTBIT;
]XEUD1N;I break;
)`K!XX$% case VK_CONTROL:
#oJ%i+V MaskBits&=~CTRLBIT;
J~|:Q.Rt` break;
4(&sw<k case VK_SHIFT:
ffR<G&"n~b MaskBits&=~SHIFTBIT;
pvhN.z break;
..Bf-)w default: //judge the key and send message
zKfY0A R break;
c7A]\1 ~ }
[Gc9
3PA7q for(int index=0;index<MAX_KEY;index++){
Ou{VDE if(hCallWnd[index]==NULL)
B7(bNr continue;
h^'+y1 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
;s?,QvE{r# {
a+<{!+3v SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
88Vl1d&b bProcessed=TRUE;
Y_/w}HB }
X3m) }
!q 9PO }
;]>a7o else if((lParam&0xc000ffff)==1){ //有键按下
AI]lG]q8 switch(wParam)
(}
wMU]!_ {
7{p6&xXx case VK_MENU:
dy4~~~^A MaskBits|=ALTBIT;
up2wkc8 break;
EN5F*s@r case VK_CONTROL:
H`
h]y MaskBits|=CTRLBIT;
jD?*sd break;
]v#T9QQN case VK_SHIFT:
<=%=,Yk MaskBits|=SHIFTBIT;
ufJHC06 break;
9JJk\, default: //judge the key and send message
DDe`Lb%% break;
kOQ!]-; }
BK1I_/_! for(int index=0;index<MAX_KEY;index++){
O+t'E9Fa if(hCallWnd[index]==NULL)
{J-Ojw|Y b continue;
^bECX<,H if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
|y4j:`@. {
A'n{K# SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
!-4VGt&c, bProcessed=TRUE;
E.G]T#wt0 }
Va^(cnwa }
{dwlW`{ }
/%TL{k&m$ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
+|qw>1J( for(int index=0;index<MAX_KEY;index++){
L=&}s[5 if(hCallWnd[index]==NULL)
EP{/]T continue;
W8M(@*
T if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
~YXkAS: SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
@_
Tq>tOr& //lParam的意义可看MSDN中WM_KEYDOWN部分
Tr,
zV }
WQsu}_g5y }
*RFBLCt }
j-wKm_M#jX return CallNextHookEx( hHook, nCode, wParam, lParam );
*mn"GK6 }
S}6xkX @ssT$#)$! 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:
Tj6kCB av~kF BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
5YLc4z* BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
zA|)9Dq IGo+O*dMw 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:
>XW-W );{76 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
gUme({h&| {
^(KDtc if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
u56F;y {
UQjYWXvi //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
De<i
8/^= SaveBmp();
y 7z)lBy\ return FALSE;
$Km~x }
m`n#Q#6 …… //其它处理及默认处理
!{vZvy" }
M|7][!<G! 9r
](/"=f d3NER} f4V 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
"8E=*2fcw x^McUfdr| 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
=]o2{d Uurpho_~ 二、编程步骤
#I#_gjJkx K4b2)8
1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
#)4p,H 3U*4E?g 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
L;fz7?_j =69sWcC8 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
gi+FL_8CzU ~J
>Jd 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
HBA|NV3. t-Ble 5、 添加代码,编译运行程序。
G<Urj+3/Xo Nhtc^DX 三、程序代码
,My'_"S? X$eR RSW ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
yF-`f
_ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
HcpAp]L) #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
TJ|do`fw> #if _MSC_VER > 1000
9{%/I
#pragma once
D4*_/,} #endif // _MSC_VER > 1000
NKRm# #ifndef __AFXWIN_H__
U"Y/PBs, #error include 'stdafx.h' before including this file for PCH
0CI\Yd= #endif
10tTV3`IM #include "resource.h" // main symbols
u ^M'[<{ class CHookApp : public CWinApp
q-S#[I+g {
VRg
y public:
oAvLSFn CHookApp();
c=re( // Overrides
NleMZ // ClassWizard generated virtual function overrides
$p*.[) //{{AFX_VIRTUAL(CHookApp)
_jaB[Q=By public:
L#fK
,r8 virtual BOOL InitInstance();
o'? WWJK6w virtual int ExitInstance();
o+}G/*O8 //}}AFX_VIRTUAL
j%gle%_ //{{AFX_MSG(CHookApp)
xEufbFAN? // NOTE - the ClassWizard will add and remove member functions here.
v3wq- // DO NOT EDIT what you see in these blocks of generated code !
>b8-v~o{ //}}AFX_MSG
?>My&yB DECLARE_MESSAGE_MAP()
.u]d5z
BR };
W*2P+H% LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
R:[#OH.c BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
0D0uzUD- BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Hk$do`H-=Y BOOL InitHotkey();
^-F#"i|Cn BOOL UnInit();
1B$8<NCQ=? #endif
n*TKzn4E l-5O5|C //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
n^nQrRIp #include "stdafx.h"
{MUO25s02 #include "hook.h"
- %?>1n #include <windowsx.h>
TCi0]Y~a #ifdef _DEBUG
g!i45]6[Nw #define new DEBUG_NEW
Nh !U #undef THIS_FILE
+~7[T/v+n static char THIS_FILE[] = __FILE__;
h;mOfF #endif
TQOJN #define MAX_KEY 100
h7S;
4] #define CTRLBIT 0x04
3wQ\L=
#define ALTBIT 0x02
!Nbi&^k B #define SHIFTBIT 0x01
H~:g=Zw #pragma data_seg("shareddata")
2\gbciJ[{( HHOOK hHook =NULL;
1+l[P9?R[ UINT nHookCount =0;
m-qOyt static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
#t
VGqf static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
|r4&@) static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
y }h2 static int KeyCount =0;
1z3I^gI*i static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
OW8TiM
mK #pragma data_seg()
^.Q/iXgh HINSTANCE hins;
+:z%#D void VerifyWindow();
pf0uwXo BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
1EHNg<J( //{{AFX_MSG_MAP(CHookApp)
?[lKft
// NOTE - the ClassWizard will add and remove mapping macros here.
Hk;) l3oB // DO NOT EDIT what you see in these blocks of generated code!
x BMhk9b^0 //}}AFX_MSG_MAP
1rhQ{6 END_MESSAGE_MAP()
oNr~8CA` gkNvvuQXc CHookApp::CHookApp()
s&zg!~@5b {
d[I}+%{[ // TODO: add construction code here,
tr\}lfK% // Place all significant initialization in InitInstance
/8w
_jjW }
bI~(<-S~K j:{d'OV CHookApp theApp;
X+T
+y>ea LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
hUy\)GsT {
cB9`U4< BOOL bProcessed=FALSE;
cM;&$IjCt if(HC_ACTION==nCode)
*@r)3 {
FU|c[u|z if((lParam&0xc0000000)==0xc0000000){// Key up
MhZT<6 switch(wParam)
p`3pRrER {
(!U5B
Hnd case VK_MENU:
;w,g|=RQ MaskBits&=~ALTBIT;
0'm4
)\ break;
L
s=2! case VK_CONTROL:
N&!qur \ MaskBits&=~CTRLBIT;
[g_Cg=J break;
`}KK@(Y case VK_SHIFT:
zF'{{7o MaskBits&=~SHIFTBIT;
qh/q< break;
_'k?9eN` default: //judge the key and send message
C
G~)` break;
] }XK }
m-lUgx7 for(int index=0;index<MAX_KEY;index++){
yG5T;O& if(hCallWnd[index]==NULL)
#_}lF<k continue;
,>n 4
`A if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
^IuHc_ {
9~DoF]TM SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
W
xyQA:3s bProcessed=TRUE;
Cd.pMoS }
B&_ 62` }
P. P3/, }
h3D8eR. else if((lParam&0xc000ffff)==1){ //Key down
z]> 0A switch(wParam)
t$8f:*6(* {
@6>R/] case VK_MENU:
Zr_{Z@IpU MaskBits|=ALTBIT;
KUVsCmiT break;
TSmuNCR case VK_CONTROL:
ho2o/>Ef3 MaskBits|=CTRLBIT;
~wIVw} break;
A0yRA+ case VK_SHIFT:
Qv,|*bf MaskBits|=SHIFTBIT;
Z$Ynar break;
T5&jpP`M default: //judge the key and send message
;Yyg(Ex break;
oU% rP }
"'p:M,: for(int index=0;index<MAX_KEY;index++)
Kjc"K36{L {
JGX E{FT if(hCallWnd[index]==NULL)
$SRpFz5y$ continue;
<s2IC_f<+ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
}RYr) {
9e^[5D=L SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
(Ybc~M)z bProcessed=TRUE;
thDQ44<#) }
{'E%SIRZ) }
]Vo;ZY_\ }
LoSblV if(!bProcessed){
h^D?G2O for(int index=0;index<MAX_KEY;index++){
a&6 3[p.<} if(hCallWnd[index]==NULL)
Zk__CgS# continue;
_(5SiK R if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
|)* K#%j SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
F?\XhoJ3G }
VUxuX5B3M }
d
}=fJ }
%/"I.\%d
return CallNextHookEx( hHook, nCode, wParam, lParam );
q,F\8M\$ }
a$yAF4HR< ~ P"@^cq BOOL InitHotkey()
I'HPy.PV {
$~!%Px) if(hHook!=NULL){
H3-(.l[!b) nHookCount++;
F-AU'o
* return TRUE;
c?5?TJpm }
[NE|ZL~ else
GT.1,E,Vw hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
"uCO?hv0 if(hHook!=NULL)
R !g'zS' nHookCount++;
z]_2lx2e return (hHook!=NULL);
fF6bEJl3 }
`-t8ag3 BOOL UnInit()
=LXjq~p {
e}dGK=` if(nHookCount>1){
&1/OwTI4J nHookCount--;
P5Lb)9_Jw return TRUE;
"<Ozoo1&w }
r{>Q{$Q BOOL unhooked = UnhookWindowsHookEx(hHook);
5aj%<r if(unhooked==TRUE){
.~$!BWP nHookCount=0;
srPczVG* hHook=NULL;
y1{TVpN }
e,kxg^ return unhooked;
Qb%o%z?hee }
QyghNImp R
+
~b@ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Mj&G5R~_ {
f=k_U[b4> BOOL bAdded=FALSE;
oyB
gF\ for(int index=0;index<MAX_KEY;index++){
\sMe2OL#z if(hCallWnd[index]==0){
+m9ouF hCallWnd[index]=hWnd;
H*j!_>W HotKey[index]=cKey;
l-Be5?|{_ HotKeyMask[index]=cMask;
z$gtGrU bAdded=TRUE;
1 | KeyCount++;
lihIPMU break;
Nq9\ 2p }
80zpRU" }
IM% ,A5u return bAdded;
beaSvhPU }
Y-UXr8 -MRX@ a^1 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
i;rcgd {
[
*Dj7zt: BOOL bRemoved=FALSE;
Fc#Sn2p* for(int index=0;index<MAX_KEY;index++){
4O{G^; if(hCallWnd[index]==hWnd){
zuu<;^/R if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
6P3h955c hCallWnd[index]=NULL;
7Db}bDU1
| HotKey[index]=0;
k".kbwcaF HotKeyMask[index]=0;
;L,i">_%u[ bRemoved=TRUE;
|Fz ^(US KeyCount--;
&wAVO_s break;
[]v$QR&u#v }
^,0Lr$+ }
#dKy{Q3he }
/ej[oR return bRemoved;
U
shIQh }
iciKjXJ: #i.,+Q void VerifyWindow()
O wuc9 {
)Gavjj&uJ for(int i=0;i<MAX_KEY;i++){
x3g4 r_ if(hCallWnd
!=NULL){ %ufh
if(!IsWindow(hCallWnd)){ ~4pP(
JP
hCallWnd=NULL; ; >>n#8`
HotKey=0; jQxhR
HotKeyMask=0; #|4G,!
KeyCount--; $|xSM2
} Ml$<x"Q
} 67hfv e
} ~+j2a3rv-{
} 9Vqy<7i1
5[g\.yi2_]
BOOL CHookApp::InitInstance() ^GAJ9AF@(
{ 0
zK{)HZ
AFX_MANAGE_STATE(AfxGetStaticModuleState()); e@qH!.g)
hins=AfxGetInstanceHandle(); ]/kpEx
InitHotkey(); 5VP0Xa ~
return CWinApp::InitInstance(); 04jvrde8-O
} F$(ak;v}
5wmd[YL
int CHookApp::ExitInstance() Bcarx<P-p
{ Db<#gH
VerifyWindow(); E(j#R"
UnInit(); .=9WY_@SZ
return CWinApp::ExitInstance(); /zt M'
} hO&b\#@~
A$r$g\5+
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file \7i_2|w
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) s:7/\h
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ njf\fw_
#if _MSC_VER > 1000 u*v<