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:
Dpp3]en.
ed$g=qs> 一、实现方法
[|PVq#( x]|8 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
.8[B
}S( uKF?UXc #pragma data_seg("shareddata")
HlEp
Dph% HHOOK hHook =NULL; //钩子句柄
Eyu]0+ UINT nHookCount =0; //挂接的程序数目
"TB4w2?= static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
+-~hl static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
BH _y0[y static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
pE(\q+1< static int KeyCount =0;
^b=] =w static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
9B&QY 2v #pragma data_seg()
0MDdcjqw :|/bEP]p/ 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
Rh#0EbE2 AA&398F DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
ncS.~F ro{q':Z3 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
cn1CM'Ru cKey,UCHAR cMask)
~#3h-|]* {
Gxk=]5<7 BOOL bAdded=FALSE;
.U|e#t for(int index=0;index<MAX_KEY;index++){
V
{R<R2h1 if(hCallWnd[index]==0){
g
_fvbVX hCallWnd[index]=hWnd;
Bs2.$~ HotKey[index]=cKey;
oK1"8k|Z HotKeyMask[index]=cMask;
yGl
(QLk bAdded=TRUE;
v#u]cmI KeyCount++;
vaQZ1a, break;
HPVW2Y0_N }
o3*IfD }
.sNUU 3xSC return bAdded;
9!sx }
jR<yV //删除热键
`M?C( BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
c|q!C0X[ {
-
Z?rx5V;t BOOL bRemoved=FALSE;
ldcYw@KQ for(int index=0;index<MAX_KEY;index++){
}}Ah-QU if(hCallWnd[index]==hWnd){
='f<_FD if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
]Hk8XT@Q+ hCallWnd[index]=NULL;
<4s$$Uw}6% HotKey[index]=0;
NQefrof HotKeyMask[index]=0;
5
OR L bRemoved=TRUE;
>o #^r; KeyCount--;
'@'~_BBZP break;
|@pJ] }
"-JJ6Bk }
pnin;;D* }
\zA$|)
x return bRemoved;
cF{5[?wS }
xzF@v>2S+ hl}@ha4' .QX|:]|n DLL中的钩子函数如下:
xi=Z<G JzH\_,, LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
0KqG J:Ru {
'/+l\.z"& BOOL bProcessed=FALSE;
D&_Ir>"\ if(HC_ACTION==nCode)
!FOPFPn {
VQE8hQ37 if((lParam&0xc0000000)==0xc0000000){// 有键松开
z:f[<`,GT switch(wParam)
tK)E*! {
*k'D%}N: case VK_MENU:
<%klrQya MaskBits&=~ALTBIT;
vUBkoC2Q break;
!f\,xa|M case VK_CONTROL:
%Y8#I3jVJ MaskBits&=~CTRLBIT;
q,-bw2 break;
xEtzqP<] case VK_SHIFT:
hKv3;jcd MaskBits&=~SHIFTBIT;
UlQZw*ce break;
]$/TsN default: //judge the key and send message
vH_QSx;C# break;
nW2fB8yq }
[B3qZ" for(int index=0;index<MAX_KEY;index++){
K~**. NF-n if(hCallWnd[index]==NULL)
D*3\4=6x continue;
H
<1g if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Gy0zh|me {
3Gi#WV4$ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
D%k%kg0, bProcessed=TRUE;
vtw{
A} }
|0YDCMq( }
[.;$6C/? }
FEgM4m.(G< else if((lParam&0xc000ffff)==1){ //有键按下
Ho[Kxe[c switch(wParam)
+^$FA4<~ {
g(xuA^~J case VK_MENU:
w J
FEua MaskBits|=ALTBIT;
QCkPua9 break;
[?uiM^& case VK_CONTROL:
,Zs:e. MaskBits|=CTRLBIT;
GKdQ break;
vy W/f case VK_SHIFT:
1zNH[
MaskBits|=SHIFTBIT;
#
JHicx\8l break;
MB|+F default: //judge the key and send message
dUn+? break;
WCxt-+# }
v!(BS, for(int index=0;index<MAX_KEY;index++){
kzPHPERA] if(hCallWnd[index]==NULL)
~M`-sSjZs continue;
1<a+91*=e if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
x,YC/J {
hnha1
f SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
TR3_!0 bProcessed=TRUE;
ecIxiv\ }
PY=(|2tb4 }
|@KW~YlE }
ZrJAfd \5c if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
fiA_6 for(int index=0;index<MAX_KEY;index++){
BeZr5I"`} if(hCallWnd[index]==NULL)
mk?&`_X1 continue;
B[jCe5!w if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
oiYI$ql3L SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
UD1R_bL} //lParam的意义可看MSDN中WM_KEYDOWN部分
~oO>6 }
xaQ]Vjw }
eqD|3YX }
-g8G47piX: return CallNextHookEx( hHook, nCode, wParam, lParam );
O'y8[< }
yHL 2! E5 "%-fAJ 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
b:Oa4vBa En$-,8\% BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
F?Cx"JYix BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
_r+2o-ZR $(pzh:| 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
*gMo(-tN nDx}6}5) LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
<PL94 {
Sw HrHj if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
o/273I {
d*80eB9P //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
\zioIfHm SaveBmp();
>Qg`Us#y return FALSE;
4'JuK{/ A7 }
3u +A/ …… //其它处理及默认处理
cp.c$ }
iev02 8M )P Z{"/Ae5] 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。
=\]5C Rn6;@Cw 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。
"H I&dC tA'O66. 二、编程步骤
|uT|(:i84, O>UG[ZgW 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";
-_&"Q4FR;+ 5, 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
?K]Cs&E4 #(6^1S%
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;
uCGJe1!Ai> =\mAvVe 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;
T:$ a
x ?;NC(Z, 5、 添加代码,编译运行程序。
9UlR fl AwrW!)n} 三、程序代码
Gs^hqT;h Wj0=cIb ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
n[$b k_S #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
|HhqWja #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
"%$jl0i_c #if _MSC_VER > 1000
B3 f Kb#T #pragma once
Q;A1&UA2 #endif // _MSC_VER > 1000
o%dKi] #ifndef __AFXWIN_H__
D"kss5>w #error include 'stdafx.h' before including this file for PCH
v eP)ElX #endif
1#rcxUSi #include "resource.h" // main symbols
.bcoH class CHookApp : public CWinApp
Y*0 AS|r! {
+o+e*B7Eh public:
[Q(FBoI| CHookApp();
49S*f // Overrides
GG0l\!2) // ClassWizard generated virtual function overrides
8Mx+tA //{{AFX_VIRTUAL(CHookApp)
z0=(l?)# public:
9K~0:c virtual BOOL InitInstance();
-1'O virtual int ExitInstance();
xZ'-G6O
"~ //}}AFX_VIRTUAL
y(gL.08< //{{AFX_MSG(CHookApp)
fyYHwG // NOTE - the ClassWizard will add and remove member functions here.
~*aPeJ // DO NOT EDIT what you see in these blocks of generated code !
!EO*xxQ //}}AFX_MSG
f;os\8JdM DECLARE_MESSAGE_MAP()
s|*0cK!K^ };
)IN!CmpN LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
Zj,1)ii BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
37C'knW BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
iveJh2!#< BOOL InitHotkey();
(C{l4 BOOL UnInit();
.!#0eAT #endif
nymF`0HYe1 }4'5R //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
bs_>!H1 #include "stdafx.h"
@E Srj[ #include "hook.h"
5q<cZ)v#& #include <windowsx.h>
AT@m_d #ifdef _DEBUG
}_,\yC9F #define new DEBUG_NEW
QH z3 #undef THIS_FILE
3y#0Lb-y static char THIS_FILE[] = __FILE__;
.`./MRC #endif
`^3 N|76Y #define MAX_KEY 100
c*>8VW> #define CTRLBIT 0x04
l(&3s:Ud #define ALTBIT 0x02
&6ymGo #define SHIFTBIT 0x01
is?#wrV=K #pragma data_seg("shareddata")
=rL%P~0wq HHOOK hHook =NULL;
q<Tx'Y a UINT nHookCount =0;
B{}<DP. static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
1f3c3PJ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
[)efh9P* static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
S($8_u$U static int KeyCount =0;
Oy(fh%k# static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
Jd]kg,/ #pragma data_seg()
pl#2JA8 HINSTANCE hins;
tVI6GXH void VerifyWindow();
244[a]
%&; BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
4gR;,%E\TO //{{AFX_MSG_MAP(CHookApp)
@k+&89@G // NOTE - the ClassWizard will add and remove mapping macros here.
+Tf4SJ // DO NOT EDIT what you see in these blocks of generated code!
q4y P\B //}}AFX_MSG_MAP
*'?aXS -'r END_MESSAGE_MAP()
"Zh3, P8&BtA CHookApp::CHookApp()
`kE ;V!n? {
RA];hQI? // TODO: add construction code here,
o]R*6$ // Place all significant initialization in InitInstance
KM-d8^\: }
1>~bzXY# 0H9UM*O CHookApp theApp;
G4&vrM,f LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
pL [JGn {
\&!qw[;O BOOL bProcessed=FALSE;
RpmOg
if(HC_ACTION==nCode)
Py@/\V {
.z+S@s[O if((lParam&0xc0000000)==0xc0000000){// Key up
-eE r|Gs) switch(wParam)
8]@$7hy8 {
G'#f*) f case VK_MENU:
7\0}te MaskBits&=~ALTBIT;
)6!ji]c
N break;
5%r:hO @S case VK_CONTROL:
OrC}WMhd MaskBits&=~CTRLBIT;
*J D-|mK break;
If>bE!_BO case VK_SHIFT:
Mg"e$m MaskBits&=~SHIFTBIT;
,1K`w:uhS break;
_O,k0O
default: //judge the key and send message
<%Al(Lm0 break;
gJ=y7yX }
W1;QPdz: for(int index=0;index<MAX_KEY;index++){
Xp67l!{v if(hCallWnd[index]==NULL)
5^5hhm4 continue;
\rpXG9 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
;2y4^ {
J@}PBHK+ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
aPToP.e bProcessed=TRUE;
c0ue[tb }
TSKT6_IJw }
dug^o c1
}
5+DId7d'n else if((lParam&0xc000ffff)==1){ //Key down
m7#v2:OD+ switch(wParam)
e,K.bgi {
Q8H+=L: case VK_MENU:
/R(]hmW MaskBits|=ALTBIT;
xYd]|y break;
v ^R:XdH case VK_CONTROL:
"@^^niSFl MaskBits|=CTRLBIT;
<9 dfbI) break;
H`bS::JI- case VK_SHIFT:
koojF|H> MaskBits|=SHIFTBIT;
+RBX2$kB break;
;Yve m default: //judge the key and send message
+HT?>k break;
H$ZLtPv5 }
Oq9E$0JW for(int index=0;index<MAX_KEY;index++)
B&+)s5hh {
/lS5B6NU if(hCallWnd[index]==NULL)
V(5*Dn84 continue;
}?)U`zF)7} if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
cj\?vX\V {
JHXtKgFX SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
"wR1=&gk bProcessed=TRUE;
8l l}" }
q o6~)Aws }
=E
w<s5C@ }
Qv
WvS9] if(!bProcessed){
";U#aK1p for(int index=0;index<MAX_KEY;index++){
o-
v#Zl if(hCallWnd[index]==NULL)
X> T_Xc continue;
a@S{A5j if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Kw7uUJR SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
[G",Yky }
3;JF5e\?x }
.TM.
v5B }
Y#t9DhzFWo return CallNextHookEx( hHook, nCode, wParam, lParam );
X #>:9 }
C
%i{{Y&l g#q7~#9 BOOL InitHotkey()
UOpSH{N {
U4NH9-U' if(hHook!=NULL){
zRMz8IC. nHookCount++;
r"9hpZH return TRUE;
I {%Y0S }
4YSVy2x else
Lz&FywF-l hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
D>-srzw if(hHook!=NULL)
7<ZGNxZ~ nHookCount++;
cE^Ljk return (hHook!=NULL);
L0)w~F
?m }
l*
z"wA- BOOL UnInit()
nR=!S5>S {
USg,=YM if(nHookCount>1){
&. MUSqo9 nHookCount--;
9H/C(Vo return TRUE;
GOsOFs "I }
#p<(2wN BOOL unhooked = UnhookWindowsHookEx(hHook);
_fdD4-2U if(unhooked==TRUE){
jmG)p|6 nHookCount=0;
9tWpxrig% hHook=NULL;
(l -l
Y }
ZPG~@lU return unhooked;
kni{1Gr }
Iqci}G%r y>X(GF^ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Px3I+VP {
<@$+uZt+ BOOL bAdded=FALSE;
Ss3~X90!*B for(int index=0;index<MAX_KEY;index++){
Q?bCQZ{-Lh if(hCallWnd[index]==0){
%ol\ sO| hCallWnd[index]=hWnd;
[Z2{S-)UM HotKey[index]=cKey;
mM r$~^P: HotKeyMask[index]=cMask;
^-Rqlr,F; bAdded=TRUE;
^3ai}Ei3 KeyCount++;
^#t6/fY.# break;
IF cre }
)KY4BBc }
t`Rbn{ return bAdded;
AyNpY_B0c }
v|KGzQx$.* nvCp-Z$ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
EiDnUL(W7h {
Ng2Z7k BOOL bRemoved=FALSE;
XmP,3KG2{S for(int index=0;index<MAX_KEY;index++){
h1)ny1; if(hCallWnd[index]==hWnd){
- zUBK if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
p"6ydXn% hCallWnd[index]=NULL;
IML.6<,(Z HotKey[index]=0;
CkRilS< HotKeyMask[index]=0;
S5:&_&R8[ bRemoved=TRUE;
8>9MeDE KeyCount--;
$DaQM'- break;
:r2d%:h%2 }
}KYOde@ }
voFg6zoV_ }
kxR!hA8wv4 return bRemoved;
v cUGBGX_& }
=
c1>ja )5`~WzA void VerifyWindow()
4M!wm]n/%5 {
xLb=^Xjec for(int i=0;i<MAX_KEY;i++){
+tlBOl$ if(hCallWnd
!=NULL){ 3ZbqZ"rE
if(!IsWindow(hCallWnd)){ ArjRoXDE
hCallWnd=NULL; x+TdTe;p
HotKey=0; da~_(giD*
HotKeyMask=0; G^cMY$?99
KeyCount--; /;TtMQt
} >5E1y!
} 7PuYrJ
} {>PEl;,-
} B873UN
@LFB}B
BOOL CHookApp::InitInstance() t&p I
{ XwfR/4
AFX_MANAGE_STATE(AfxGetStaticModuleState()); AyW=.
hins=AfxGetInstanceHandle(); |26[=_[q
InitHotkey(); A^$xE6t
return CWinApp::InitInstance(); K2\)9
} cq 5^7.
yJ`{\7Uqg
int CHookApp::ExitInstance() y>:U&P^
{ `A5n6*A7
VerifyWindow(); CbXSJDs
UnInit(); E^gN]Z"O
return CWinApp::ExitInstance(); ?bu=QV@
} p5py3k
)*R';/zaI
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file MIyT9",Pl
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) ho)JY
$#6
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ }I MV@z B
#if _MSC_VER > 1000 ;y{(#X#
#pragma once ?S9vYaA$
#endif // _MSC_VER > 1000 "LH!Trl@k
jt(GXgm
class CCaptureDlg : public CDialog WgG$ r
{ )#1!%aQ
// Construction 2#00<t\
public: 4"3.7.<Q`
BOOL bTray; }D?qj3?bj
BOOL bRegistered; SSbx[<E3
BOOL RegisterHotkey(); ^7*7^<
UCHAR cKey; MslgQmlM
UCHAR cMask; Q, "8Ty
void DeleteIcon(); pr1bsrMuL
void AddIcon(); )pe17T1|
UINT nCount; LE)$_i8gX
void SaveBmp(); xX9snSGz
CCaptureDlg(CWnd* pParent = NULL); // standard constructor dz>Jl},`k
// Dialog Data X 5X D1[
//{{AFX_DATA(CCaptureDlg)
H:9G/Nev
enum { IDD = IDD_CAPTURE_DIALOG }; S{v]B_N[M
CComboBox m_Key; RnU7|p{
BOOL m_bControl; FA;-D5=
BOOL m_bAlt; T$AVMVq
BOOL m_bShift; A|]#b?-
CString m_Path; 'x<oILOG
CString m_Number; 2`%a[t@M.
//}}AFX_DATA hg:$H9\%
// ClassWizard generated virtual function overrides eX lJ=S}
//{{AFX_VIRTUAL(CCaptureDlg) *W^a<Zm8>
public: gHkHAOe/
virtual BOOL PreTranslateMessage(MSG* pMsg); [Y?Y@x"MZ
protected: QSn18V>{
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support B[6k
[Vs
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); @HSK[[?
//}}AFX_VIRTUAL ;<