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:
7ABHgw~?8r
u2JkPh&!rq 一、实现方法
H6bomp" }@!d(U* 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:
A{y3yH`#h Ny\iRU)fN #pragma data_seg("shareddata")
NAx( Qi3 HHOOK hHook =NULL; //钩子句柄
onG,N1`+ UINT nHookCount =0; //挂接的程序数目
1g2%f9G static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
R4E0avt static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
"EWU:9\0 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
hKt
AvTg static int KeyCount =0;
Rk2ZdNc\ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
*~prI1e( #pragma data_seg()
D3;^!ln]D i3rvDch
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。
Q(oWaG D@>P%k$$s> 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:
@l$cZie u;h9Ra1 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
>fdS$,`A cKey,UCHAR cMask)
%}+j4n {
b0m1O.&I_ BOOL bAdded=FALSE;
`@")R- for(int index=0;index<MAX_KEY;index++){
`(W
V pP? if(hCallWnd[index]==0){
$-5iwZ hCallWnd[index]=hWnd;
04WKAP'c
N HotKey[index]=cKey;
frc>0\ HotKeyMask[index]=cMask;
3L=vsvO4 bAdded=TRUE;
Ndx.SOj KeyCount++;
|+x;18 break;
rZ w&[ G }
bveNd0hN }
6LNm>O return bAdded;
_BHb0zeot }
i. `S0 //删除热键
ra_`NsKF} BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
hh
<=D.u {
'n)M0e BOOL bRemoved=FALSE;
e,`+6qP{ for(int index=0;index<MAX_KEY;index++){
)-2OraUm< if(hCallWnd[index]==hWnd){
O'$0K0k3 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
KB*[b hCallWnd[index]=NULL;
{B\ar+ 9> HotKey[index]=0;
Gob1V HotKeyMask[index]=0;
'S@h._q bRemoved=TRUE;
~?[%uGI0h KeyCount--;
oKA8)~Xqou break;
5<,}^4wWZ }
}"Hf/{E$_" }
ylmf^G@JC }
fo4j^,` return bRemoved;
L$i&>cF\_> }
l_ >^LFOA wKXKc\r Z fL\3Mn DLL中的钩子函数如下:
Co[ rhs J@p[v3W LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
xh_6@}D2J {
MFiX8zwhx+ BOOL bProcessed=FALSE;
{p
yo if(HC_ACTION==nCode)
iN<& {
yZUB8erb. if((lParam&0xc0000000)==0xc0000000){// 有键松开
8iqx*8} switch(wParam)
6$9n_AS {
wrac\. case VK_MENU:
bkLm]n3 MaskBits&=~ALTBIT;
efl6U/'Ij break;
"9&6bBa case VK_CONTROL:
E`u=$~K MaskBits&=~CTRLBIT;
m~(]\ break;
^r}^- case VK_SHIFT:
%RdCSQ9~ MaskBits&=~SHIFTBIT;
J0C,KU( break;
C8-4 m68" default: //judge the key and send message
Nt$/JBB[$ break;
B9>3xxp(by }
{S'xZ._= for(int index=0;index<MAX_KEY;index++){
,*@m<{DX) if(hCallWnd[index]==NULL)
`:}GE@] continue;
`k
a!`nfo if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
>e>Q'g{ {
LXJ"ct SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
?h<I:[oZ bProcessed=TRUE;
8ooj) }
$s)G0/~W }
vp[~%~1( }
hGcOk[m 4 else if((lParam&0xc000ffff)==1){ //有键按下
^7.864 switch(wParam)
=V/$&96Q {
.px*.e s case VK_MENU:
YaFQy0t%/5 MaskBits|=ALTBIT;
D?)"Z$ break;
oz(<e case VK_CONTROL:
% )i?\(/ MaskBits|=CTRLBIT;
`Ft.Rwj2:m break;
8N'`kd~6[ case VK_SHIFT:
`N_N zH MaskBits|=SHIFTBIT;
1WfN_JKB5 break;
ALiA+k N default: //judge the key and send message
/IxMRi= break;
Yih^ZTf]O? }
)^|zuYzN for(int index=0;index<MAX_KEY;index++){
:05>~bn>pC if(hCallWnd[index]==NULL)
_o8il3 continue;
lw\OsB$ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
BikmAa {
INyreoMp SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
8;5 UO,`T bProcessed=TRUE;
C8m8ys }
S"!nM]2L }
5$`i)}:s }
|0vY'A)] if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
Gm}ecW for(int index=0;index<MAX_KEY;index++){
u%Hegqn if(hCallWnd[index]==NULL)
vnw83a%3 continue;
W=M]1hy if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
B+ud-M0 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
?>*i8* //lParam的意义可看MSDN中WM_KEYDOWN部分
Be68 Fu0 }
Ep|W> }
5 UpN/\He }
Xjt/ G):L return CallNextHookEx( hHook, nCode, wParam, lParam );
"]f0wLzh }
x\]%TTps ;$ D*,W
* 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:
DBWe>Ef( y[UTuFv~Q BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
r{pTMcDS BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
@SF*Kvb& ytf.$P 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
U!r2`2LY [[}KCND LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
Pn\ Lg8 {
Z!0D97^ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
(|(#~o]40t {
>V2Tr$m j //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
qgbp-A!2zF SaveBmp();
{9q~bt return FALSE;
K9\`Wu_qL }
hF"yxucj$ …… //其它处理及默认处理
9+)5 #!0 }
?B.>VnYZ/a f7c%Z:C#Y -/*-e
/+b 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。
.>%(bH8S `rzgC \ 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。
6nV]Ec~3[ jc)[5i0 二、编程步骤
~mP#V k\8]fh)J\7 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";
^
ry
2fM*6CaS 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
E96FwA5 T$RVz
3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
'B ocMjRA e~w-v"' 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
Q>]FO dY'/\dJ 5、 添加代码,编译运行程序。
r8x<-u4 FvQ>Y')R7Z 三、程序代码
T~@$WM( M}2a/}4 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
D|lp3\`% #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
Q^}6GS$ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
Goa0OC, #if _MSC_VER > 1000
[(Ss^?AJW #pragma once
^EY^.?Mg #endif // _MSC_VER > 1000
<2@V$$Qg.~ #ifndef __AFXWIN_H__
y,e#e` #error include 'stdafx.h' before including this file for PCH
rvrv[^a( #endif
4d~Sn81xW #include "resource.h" // main symbols
@k~'b class CHookApp : public CWinApp
]w ^9qS {
Y|$3%t public:
X&R,-^ CHookApp();
l'TM^B)`c // Overrides
|t](4 // ClassWizard generated virtual function overrides
Kgh@.Ir //{{AFX_VIRTUAL(CHookApp)
d/oxRzk'L public:
=s3f{0G virtual BOOL InitInstance();
>Wvb!8N virtual int ExitInstance();
5H8]N#Y& //}}AFX_VIRTUAL
LA?h +) //{{AFX_MSG(CHookApp)
&+]x // NOTE - the ClassWizard will add and remove member functions here.
C8 [W // DO NOT EDIT what you see in these blocks of generated code !
}&|S8: //}}AFX_MSG
x
xMV2&,Jq DECLARE_MESSAGE_MAP()
x`:zC# };
V}de|= LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
p1^k4G BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
rq=D[vX\N( BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
|oCE7'BaP BOOL InitHotkey();
]7 W! BOOL UnInit();
yKSvg5lLy #endif
c~j")o #{97<sU\ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
;.Dm?J0 #include "stdafx.h"
NJ"
d` #include "hook.h"
YMGzO #include <windowsx.h>
iBlZw%zKP #ifdef _DEBUG
ig:E`Fe@ #define new DEBUG_NEW
Z*,Nt6;e #undef THIS_FILE
ibe#Y static char THIS_FILE[] = __FILE__;
c*iZ6j"iI #endif
~{-zj #define MAX_KEY 100
"zpc)'$L= #define CTRLBIT 0x04
ean_/E #define ALTBIT 0x02
R`%C]uG #define SHIFTBIT 0x01
0|mF
/ #pragma data_seg("shareddata")
9WE_9$<V HHOOK hHook =NULL;
p%MH**A UINT nHookCount =0;
|"7F`M96I static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
~o"VZp static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
/F/zMZGSA{ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
h?UUd\RU) static int KeyCount =0;
HP`dfo~j static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
(A@~]N,U/ #pragma data_seg()
k{M4.a[( HINSTANCE hins;
_T[7N|'O void VerifyWindow();
%5) 1^ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
*CsRO //{{AFX_MSG_MAP(CHookApp)
\J@i:J6x$1 // NOTE - the ClassWizard will add and remove mapping macros here.
7t8[M( // DO NOT EDIT what you see in these blocks of generated code!
HfQZRDH //}}AFX_MSG_MAP
,\t:R1. END_MESSAGE_MAP()
5X8GR5P }cl~Vo-mp CHookApp::CHookApp()
~3,>TV {
rUg<(/c // TODO: add construction code here,
\U(;%V // Place all significant initialization in InitInstance
iR_j
h=2{ }
d<x7* OW) e|6kgj3/ CHookApp theApp;
$ NNd4d* LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
(Nzup3j {
"4`i]vy8 BOOL bProcessed=FALSE;
4V2}'/|[ if(HC_ACTION==nCode)
D's Tv}P {
Z>9uVBE02 if((lParam&0xc0000000)==0xc0000000){// Key up
UG@9X/l} switch(wParam)
<FaF67[Q {
n\X'2 case VK_MENU:
PTt#Ixn, MaskBits&=~ALTBIT;
mgODJ break;
nTG @=C# case VK_CONTROL:
NVt612/'7y MaskBits&=~CTRLBIT;
:TPT]q
d@ break;
3e)W_P*0? case VK_SHIFT:
bSG}I| MaskBits&=~SHIFTBIT;
\B72 #NR break;
]RBT9@-:U default: //judge the key and send message
1KHFzx, break;
( o(, ; }
<./r%3$;7 for(int index=0;index<MAX_KEY;index++){
n8FmIoZ&` if(hCallWnd[index]==NULL)
nBN+.RB:( continue;
#![9QUvcf if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
jV}tjwq {
xJ&E2Bf SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
[WfigqY`b* bProcessed=TRUE;
%ZKP d8 }
J*!_kg)>J }
6h?v/\ }
80'!XKSP else if((lParam&0xc000ffff)==1){ //Key down
>TKl`O switch(wParam)
bXiOf#:'' {
X&bz%I>v case VK_MENU:
XABB6J] MaskBits|=ALTBIT;
6d# 7 break;
C>MEgGP case VK_CONTROL:
/QgU!:e MaskBits|=CTRLBIT;
d~|/LR5 break;
?z[k.l+6w case VK_SHIFT:
p;x3gc;0 MaskBits|=SHIFTBIT;
5#WyI#YNG break;
u/ Gk>F default: //judge the key and send message
,f[`C-\Q% break;
?=},%^ }
f"Z2,!Z; for(int index=0;index<MAX_KEY;index++)
aioN)V {
((AsZ$[S if(hCallWnd[index]==NULL)
B-.QGf8K. continue;
^e~m`R2fHh if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
o8ERU($/ {
[YTOrN SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
fZ6-ap,u bProcessed=TRUE;
5bZjW~d }
us,~<e0 }
,,Ia 4c
}
'CfM'f3uu if(!bProcessed){
6?(Z f for(int index=0;index<MAX_KEY;index++){
"J=A(w5 if(hCallWnd[index]==NULL)
!A|ayYBb\ continue;
-qDM(zR if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
qt.Y6s:r_ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
B*-A erdH }
%"gV>E_u }
g.:b\JE ` }
+gh*n,:| return CallNextHookEx( hHook, nCode, wParam, lParam );
S O#R5Mu2N }
u 6"v}gN (oG-h"^/ BOOL InitHotkey()
~]l
T>|X {
}~bx==SF6! if(hHook!=NULL){
8j^3_lD nHookCount++;
M!#[(: return TRUE;
2+'4 m#@) }
rv26vnJy" else
8)m hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
^;DbIo\6H if(hHook!=NULL)
&`}8Jz=S nHookCount++;
iqAME%m return (hHook!=NULL);
\*r]v;NcP }
QZO9CLX 8k BOOL UnInit()
G@+AB*Eu {
:h!&.FB if(nHookCount>1){
mcm8|@Y{ nHookCount--;
5a^b{=#Y return TRUE;
bKb}VP }
hL(zVkYI BOOL unhooked = UnhookWindowsHookEx(hHook);
/q\{Os rX if(unhooked==TRUE){
w`a(285s)i nHookCount=0;
3w!,@=.q hHook=NULL;
JQdeI+ }
X ^\kI1 return unhooked;
5.o{A#/NTl }
\66j4?H# <7X6ULQ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
#>[5NQ;$' {
9+"\7MHw BOOL bAdded=FALSE;
TxDzGC for(int index=0;index<MAX_KEY;index++){
lRr ={
>s if(hCallWnd[index]==0){
tI;pdR] hCallWnd[index]=hWnd;
P+s-{vv{0 HotKey[index]=cKey;
NUjo5.7 HotKeyMask[index]=cMask;
0X:
:<N@ bAdded=TRUE;
Ix1[ $9 KeyCount++;
7$/%c{o break;
\}9GK`oR }
/GDGE } }
-'wFaW0%I return bAdded;
}3xZ`vX[T }
GJB=5nE C?47v4n-' BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
1}>u Y {
c=Y8R/G< BOOL bRemoved=FALSE;
hq[RU&\ for(int index=0;index<MAX_KEY;index++){
vi-mn)L6# if(hCallWnd[index]==hWnd){
SeX:A)*ez% if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
xOgUX6n hCallWnd[index]=NULL;
@2eV^eO9 HotKey[index]=0;
Ei&
Z HotKeyMask[index]=0;
@w]z"UCwV@ bRemoved=TRUE;
e|&}{JP{[ KeyCount--;
YnLwBJ 2i break;
zbM*/:Y }
`kERM-@A }
JRT,%;*, }
Y\pRk6, return bRemoved;
ZZJXd+Q} }
v?S~ =$. 5Rc^5Nv void VerifyWindow()
{6uh Ub
{
u>U4w68 for(int i=0;i<MAX_KEY;i++){
H*&ZXAKv if(hCallWnd
!=NULL){ <Z6tRf;B
if(!IsWindow(hCallWnd)){ SSh=r
hCallWnd=NULL; us,1:@a)a
HotKey=0; <GthJr>1D
HotKeyMask=0; (b}}'
KeyCount--; yk<$XNc
} AT6:&5_`
} Gd08RW
} kk*:S* ,
} eJm7}\/6`
Zagj1OV|
BOOL CHookApp::InitInstance() O*d4zBT
{ nR()ei^X
AFX_MANAGE_STATE(AfxGetStaticModuleState()); `AO<r
hins=AfxGetInstanceHandle(); %j*i=
InitHotkey(); Q:#Kt@W
return CWinApp::InitInstance(); W18I"lHeh
} ;& PK6G
p>c` GDU
int CHookApp::ExitInstance() DIU9Le
{ .;'3Roi
VerifyWindow(); `Rc7*2I)l
UnInit(); ~il{6Z+#n
return CWinApp::ExitInstance(); mm5y'=#
} L`!M3c@u
+.RC{o,
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file Qf}^x9'
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) [v!TQwMU
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ Y^(Sc4 W
#if _MSC_VER > 1000 W?B(Jsv
#pragma once DrTo")T
#endif // _MSC_VER > 1000 \\WIu?
|4F3Gu
class CCaptureDlg : public CDialog g+-=/Ge
{ _E{hB
// Construction 3N]
public: 8] BOq:
BOOL bTray; aB(6yBBoxj
BOOL bRegistered; f~3_Rv!
BOOL RegisterHotkey(); 1{.=T&eG#
UCHAR cKey; ]757oAXl
UCHAR cMask; s]X]jfA.
void DeleteIcon(); | Ts0h?"a
void AddIcon(); r95l.v
UINT nCount; r9a?Y!(
void SaveBmp(); j3W)5ZX
CCaptureDlg(CWnd* pParent = NULL); // standard constructor KvM}g2"
// Dialog Data O-M4NKl]6
//{{AFX_DATA(CCaptureDlg) ZL3aO,G2
enum { IDD = IDD_CAPTURE_DIALOG }; )cMW,
CComboBox m_Key; ~\9bh6%R
BOOL m_bControl; =DhzV
D
BOOL m_bAlt; zLs[vg.(
BOOL m_bShift; S'I{'jP5
CString m_Path; l1RpG"
CString m_Number; =/k*w#j
//}}AFX_DATA j]#-DIL
// ClassWizard generated virtual function overrides 2#n4t2p
//{{AFX_VIRTUAL(CCaptureDlg) 39W6"^q"o
public: E! i:h62
virtual BOOL PreTranslateMessage(MSG* pMsg); }<EA)se"
protected: S=^a''bg
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support WheJ 7~
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); rf% E+bh4
//}}AFX_VIRTUAL Lmy ^/P%
// Implementation {I!sXj
protected: 8q6b3q:c
HICON m_hIcon; 2/9P&c-r