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:
YD,<]q%
0B]c`$"aD 一、实现方法
ET[>kn^# 3De(:c)@ 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:
LL_@nvu}M >H,5MM! #pragma data_seg("shareddata")
HoO1_{q" HHOOK hHook =NULL; //钩子句柄
}F';"ybrU) UINT nHookCount =0; //挂接的程序数目
9]^q!~u static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
=X;h _GQ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
m2\[L/W] static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
Vz]yJ: static int KeyCount =0;
r`Bm"xI static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
(-Qr.t_B` #pragma data_seg()
Rr0]~2R O&
1z- 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。
w&>*4=^a #OwxxUeZ 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:
wCEcMVT n+1`y8dy BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
)tx2lyY: cKey,UCHAR cMask)
9hei8L: {
Ov;q]Vn> BOOL bAdded=FALSE;
"9#hk3*GqX for(int index=0;index<MAX_KEY;index++){
J6mUU3F9f if(hCallWnd[index]==0){
HBm(l@#. hCallWnd[index]=hWnd;
jG%J.u^k HotKey[index]=cKey;
()ww9L2 HotKeyMask[index]=cMask;
T}jW,Ost bAdded=TRUE;
MP
p KeyCount++;
|)OC1=As break;
#!C|~= }
o0_H(j? }
n( 9$)B_y return bAdded;
~cf)wrP }
K?u:-QX^ //删除热键
Ie}7#>S BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Jow{7@FG {
Q">wl BOOL bRemoved=FALSE;
7|k2~\@q for(int index=0;index<MAX_KEY;index++){
e\._M$l if(hCallWnd[index]==hWnd){
}Xb|Ur43 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
l%
p4.CX hCallWnd[index]=NULL;
N>w+YFM HotKey[index]=0;
e>Dux HotKeyMask[index]=0;
E %?>
%h bRemoved=TRUE;
Xdh@ ^` KeyCount--;
;;N#'.xD break;
+4F; m_G6 }
_^D -nk? }
rX22%~1 }
LX}|%- iv return bRemoved;
y*E{X }
G_}oI|B Ckhwd AZ
SaI DLL中的钩子函数如下:
,xutI M hjIE<OI= LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
X([@}ren {
75iudki BOOL bProcessed=FALSE;
{<zE}7/2- if(HC_ACTION==nCode)
wj8\eK)]L {
BkB9u&s^ if((lParam&0xc0000000)==0xc0000000){// 有键松开
OKA6S* switch(wParam)
I5E5,{ {
:4)lmIu case VK_MENU:
Li+|%a MaskBits&=~ALTBIT;
i "aQm break;
93/`e}P"o case VK_CONTROL:
o\qeX|.70 MaskBits&=~CTRLBIT;
0R;`)V\^ break;
rS0#]Gg case VK_SHIFT:
Hp@cBj_@P2 MaskBits&=~SHIFTBIT;
*f SX3Dk break;
`(]mUW default: //judge the key and send message
ceLr;}?Ws break;
GuF-HP}xM }
%;#9lkOXWH for(int index=0;index<MAX_KEY;index++){
;L,yJ~ if(hCallWnd[index]==NULL)
D=B :tP continue;
&`_|[Y ]H if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
_zLEHEZ- {
.UU) SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
'.e5Ku bProcessed=TRUE;
{JM3drnw }
`F~Fb S }
<)+;Bg }
(kx>\FIK* else if((lParam&0xc000ffff)==1){ //有键按下
f5R%F~ switch(wParam)
jRp @-S#V {
M#yUdl7d case VK_MENU:
qJ$S3B MaskBits|=ALTBIT;
xzRC % break;
1?r$Rx<R case VK_CONTROL:
|[!0ry*N% MaskBits|=CTRLBIT;
xRF_'|e break;
<JZa case VK_SHIFT:
yCv"(fNQ MaskBits|=SHIFTBIT;
FWo`oJeN break;
&A^2hPe} default: //judge the key and send message
7>gW2m break;
Si|8xq$E; }
7A for(int index=0;index<MAX_KEY;index++){
AI .2os* if(hCallWnd[index]==NULL)
>Lz2zlZI continue;
pe+m%;nzR if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
72y!cK6 {
gIcPKj"8${ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
]xhH:kW4 bProcessed=TRUE;
2Mu(GUe; }
eoPoGC }
mW)"~sA }
QEEX|WM if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
'YEiT#+/ for(int index=0;index<MAX_KEY;index++){
e co=ia if(hCallWnd[index]==NULL)
!Tu.A@ continue;
l`];CALA4 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
!p)cP"fa SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Fh)YNW@ //lParam的意义可看MSDN中WM_KEYDOWN部分
,7e 2M@=
}
'eoI~*}3WQ }
YC}$O2 }
v=H!Y"; return CallNextHookEx( hHook, nCode, wParam, lParam );
87nsWBe }
CzT_$v_ Vb2")+*: 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:
*c@]c~hY, &J=x[{R BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
S*rc XG6Q^ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
YGLR%PYv" b$FXRR\G 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:
F,XJGD* 9a.[>4} LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
td+[Na0d {
5gPAX $j H if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
taOsC!Bp {
^[zF IO //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
;}k_2mr~ SaveBmp();
Xg97[ I8/ return FALSE;
ix}*whW=U }
K9Pw10g' …… //其它处理及默认处理
t{/
EN)J }
14\!FCe)! o-t!z'\lO yDw^xGws 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
"?sLi E9[8th,t 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
'?!2h' ;"GI~p2~7 二、编程步骤
4U:+iumy2 >l5JwwG 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
z~a]dMs"(P U0S}O(Ptr 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
z9KsSlS ^ dkbKnY& 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
F[OBPPQ3 Th*mm3D6 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
%n#^#: RrqZ5Gonj 5、 添加代码,编译运行程序。
qsL6*(S(r ?)5M3lV3k 三、程序代码
iF]vIg#h ]0:R^dHE ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
xE.=\UzJ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
S[M\com' #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
b;Im +9& #if _MSC_VER > 1000
v]27+/a$c #pragma once
? 5
V-D8k #endif // _MSC_VER > 1000
`24:Eg6r #ifndef __AFXWIN_H__
N,_ej@L8 #error include 'stdafx.h' before including this file for PCH
yc 5n #endif
'lNl><e- #include "resource.h" // main symbols
7f
td2lv class CHookApp : public CWinApp
X]*W + {
B[MZPv) public:
Bj7\{x,? CHookApp();
-nT+!3A8 // Overrides
?0Ca-T Rz // ClassWizard generated virtual function overrides
I@q>ES!1H //{{AFX_VIRTUAL(CHookApp)
g^En6n) public:
aa1XY&G"! virtual BOOL InitInstance();
;7<a0HZ5! virtual int ExitInstance();
j|(bDa4\ //}}AFX_VIRTUAL
ArU>./)Q //{{AFX_MSG(CHookApp)
BmUzsfD // NOTE - the ClassWizard will add and remove member functions here.
tg5jS]O // DO NOT EDIT what you see in these blocks of generated code !
U^0vLyqW^5 //}}AFX_MSG
Tm^zoVi DECLARE_MESSAGE_MAP()
6YU2
!x };
~K],hi^<P LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
o-Idr{ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
k*c:%vC! BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
2i(|? XJ^ BOOL InitHotkey();
{Q(6
.0R BOOL UnInit();
UmgLH Cz #endif
Da-(D<[0 1I^Sv //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
O\KAvoQ%s #include "stdafx.h"
8rp-XiW #include "hook.h"
3Ob"r` #include <windowsx.h>
X)f"`$ #ifdef _DEBUG
Z ''P5B; #define new DEBUG_NEW
RLHe;-*b]I #undef THIS_FILE
47K5[R static char THIS_FILE[] = __FILE__;
lIFU7g #endif
t2Y~MyT/ #define MAX_KEY 100
D[#\Y+N #define CTRLBIT 0x04
0~1P&Qs<
#define ALTBIT 0x02
YKc{P"'/| #define SHIFTBIT 0x01
T&23Pf 1 #pragma data_seg("shareddata")
-5ec8m8 HHOOK hHook =NULL;
Rt:PW}rFf UINT nHookCount =0;
8c|IGC static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
^ KjqS\< static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
6kuSkd$. static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
hW+Dko(s static int KeyCount =0;
T+ t-0k static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
HYH!; #pragma data_seg()
6e*b;{d HINSTANCE hins;
,/ : )FV void VerifyWindow();
j&mL]'Zy BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
l&A` //{{AFX_MSG_MAP(CHookApp)
-?'CUm*Od // NOTE - the ClassWizard will add and remove mapping macros here.
W[m_IY // DO NOT EDIT what you see in these blocks of generated code!
VV4_ //}}AFX_MSG_MAP
g0U
?s END_MESSAGE_MAP()
qpeK><o awK'XFk CHookApp::CHookApp()
nJya1AH; {
)AoFd> // TODO: add construction code here,
u~kwNN9t3 // Place all significant initialization in InitInstance
N9ufTlq
s }
>?'FH +2K S_CtEM CHookApp theApp;
M Sj0D2H LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
l!=WqIZ {
#50)D wD BOOL bProcessed=FALSE;
kt#W~n if(HC_ACTION==nCode)
"p{'984r< {
Em;b,x*U if((lParam&0xc0000000)==0xc0000000){// Key up
]`XuE-Uh switch(wParam)
4Dia#1$:J {
}BrE|'.j' case VK_MENU:
gNd
J=r4 MaskBits&=~ALTBIT;
-!cAr
< break;
^-!HbbVv case VK_CONTROL:
0)]1)z(P MaskBits&=~CTRLBIT;
Mg$9'a"[\ break;
FudD case VK_SHIFT:
%}!}2s.A MaskBits&=~SHIFTBIT;
? ^CGJ1 break;
/8>/"Z2S default: //judge the key and send message
i 8Xz break;
u&x K>7 }
([-=NT}Aq for(int index=0;index<MAX_KEY;index++){
o
z{j2% if(hCallWnd[index]==NULL)
syf"{bBe continue;
61/zrMPn if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
8!GLw-kb {
H|U/tU- SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
ek)(pJ(+# bProcessed=TRUE;
WtfOE@h }
jPNfLwVkl: }
Zbh]OCN }
8$kXC+ else if((lParam&0xc000ffff)==1){ //Key down
fNPj8\#V, switch(wParam)
EiN)TB^] {
F^z8+W case VK_MENU:
it@} dZ MaskBits|=ALTBIT;
Y0\\(0j64 break;
IJY5wP1" case VK_CONTROL:
i q:Q$z& MaskBits|=CTRLBIT;
^u!Tyb8Dk break;
Q;O)>K case VK_SHIFT:
~x"79=!W MaskBits|=SHIFTBIT;
Rl4zTAI break;
OX/.v?c default: //judge the key and send message
PX2k,% break;
_D9@<+MS* }
\_AEuz3
F for(int index=0;index<MAX_KEY;index++)
&AcFa<U {
#L:P
R> if(hCallWnd[index]==NULL)
"q^'5p] continue;
&vX!7Y if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
[=6~"!P} {
q)ql]iH SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
~hslLUE bProcessed=TRUE;
m8j-lNu }
`L#?eQ{ }
.Pes{uHg }
oz6+rM6MY if(!bProcessed){
?_>^<1I1 for(int index=0;index<MAX_KEY;index++){
.00=U;H%` if(hCallWnd[index]==NULL)
Ja v2A6a continue;
RIEv*2_O if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
uQ]]]Z(H' SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Au} ;z6k }
%Rep6=K*$ }
s.^9HuM }
KzX
,n_`an return CallNextHookEx( hHook, nCode, wParam, lParam );
$7&l6~sMQ }
S?7V
"LF `m3QT3B BOOL InitHotkey()
O+p-1 C$\ {
`XSc > if(hHook!=NULL){
RC{Z)M{~ nHookCount++;
;xO=Yhc+ return TRUE;
f\);HJbg }
EKeh>3;? else
,0uo&/Y4L hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
s"',370 if(hHook!=NULL)
)@bH" nHookCount++;
6~F#F)C' return (hHook!=NULL);
9c^skNbS }
AuDR |;i BOOL UnInit()
c@9Z&2) {
]\RSHz if(nHookCount>1){
KT];SF^Y nHookCount--;
f']sU/c= return TRUE;
}kCn@ }
9R@abm,I BOOL unhooked = UnhookWindowsHookEx(hHook);
)y`TymM[F if(unhooked==TRUE){
!jAWNK6 nHookCount=0;
<,@H;|mZ hHook=NULL;
R] Disljq }
o9i#N return unhooked;
*"ykTqa
}
~)wwX:;B_ s`#ntset0 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
4ypRyO {
8K.s@< BOOL bAdded=FALSE;
*9dV/TT~f[ for(int index=0;index<MAX_KEY;index++){
}$|%/Y if(hCallWnd[index]==0){
}O.LPQ0 hCallWnd[index]=hWnd;
dv^e9b| HotKey[index]=cKey;
8>Du HotKeyMask[index]=cMask;
P?q
G bAdded=TRUE;
U~{Sa+ KeyCount++;
HZDk
<aU/! break;
MUbhEau? }
e{fZ}`=7y }
h4XcKv+ return bAdded;
b&=]S( }
$R%+* "JzfL(yt BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
0
&*P}U}Uc {
@A
[)hk&(R BOOL bRemoved=FALSE;
u}Ei_
O<z for(int index=0;index<MAX_KEY;index++){
^273l(CZ1 if(hCallWnd[index]==hWnd){
a3O nW\N if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
|`w$|pm= hCallWnd[index]=NULL;
UvPp~N7, HotKey[index]=0;
+jq
2pFQ HotKeyMask[index]=0;
kF+ZW%6N bRemoved=TRUE;
h`?y2?O KeyCount--;
o-SRSu break;
T(Y}V[0+ }
pNp^q/-yB }
L3B8IDq }
<9@&oN+T return bRemoved;
gWFL }
8W-]t1O%! "w*@R8v void VerifyWindow()
ob0~VEH- {
'oC$6l'rQ for(int i=0;i<MAX_KEY;i++){
1 h<fJzh if(hCallWnd
!=NULL){ %z1{Kus
if(!IsWindow(hCallWnd)){ _kh>Z
hCallWnd=NULL; 9n_ eCb)H
HotKey=0; "\`>2
HotKeyMask=0; DXKyRkn6e
KeyCount--; h=hoV5d@
} %h0D)6j
} c+1vqbqHG
} =Q@6c
} *7\W=-
:ezA+=ENg
BOOL CHookApp::InitInstance() *0O<bm
{ iNt 4>
AFX_MANAGE_STATE(AfxGetStaticModuleState()); K~USK?Q%
hins=AfxGetInstanceHandle(); Mz93
InitHotkey(); 9 >%+bA(
return CWinApp::InitInstance(); ?F1wh2oq
} )eECOfmnZ
ja?s@Y}-9s
int CHookApp::ExitInstance() T4eWbNSs
{ Cgo9rC~]
VerifyWindow(); C}9Kx }q
UnInit(); &1=g A.ZR
return CWinApp::ExitInstance(); $iwIF7,\P
} 6Hda]y
I:nI6gF
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file zFOL(s.h|0
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 4X*Q6rW
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ V+46R
]
#if _MSC_VER > 1000 {b2 aL7
#pragma once > <X $#
#endif // _MSC_VER > 1000 s*f1x N<
( :iPm<
class CCaptureDlg : public CDialog dKb ^x^
{ n%*tMr9 s
// Construction >zFD$
public: +|9f%f6vp
BOOL bTray; ]9s\_A9
BOOL bRegistered; O)`Gzx*ShU
BOOL RegisterHotkey(); 4b=Gg
UCHAR cKey; N2T&,&,t
UCHAR cMask; T!(sZf
void DeleteIcon(); "ct58Y@
void AddIcon(); t?HF-zQ
UINT nCount; rfc|`*m}0
void SaveBmp(); |WBZN1W)
CCaptureDlg(CWnd* pParent = NULL); // standard constructor r,0@~;zA
// Dialog Data gX_SKy
//{{AFX_DATA(CCaptureDlg) u3ST;
enum { IDD = IDD_CAPTURE_DIALOG }; a5)JkC
CComboBox m_Key; #hy+ L
BOOL m_bControl; <