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:
_$_,r H
4*'ZabDD 一、实现方法
q.VZ P 6TDa#k5v 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
kMZo7 y wOg#J #pragma data_seg("shareddata")
@%jY HHOOK hHook =NULL; //钩子句柄
jo'
V.]\ UINT nHookCount =0; //挂接的程序数目
;FJFr*PM static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
;)FmN[ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
Q^*4FH!W static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
c#-*]6x static int KeyCount =0;
?x/Lb*a^ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
Clb7=@f #pragma data_seg()
N}nE?|N=5 t;`ULp~& 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
1zgM$p , Xxp]*K2 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:
re4A5Ev$ 5Q\ hd*+g BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
4~1lP&
cKey,UCHAR cMask)
9_O6Sl {
"RTv[n! BOOL bAdded=FALSE;
L;WFHIE for(int index=0;index<MAX_KEY;index++){
b=5ZfhIg[ if(hCallWnd[index]==0){
]=PkgOJD hCallWnd[index]=hWnd;
Hb/8X
!= HotKey[index]=cKey;
-A@/cS%p HotKeyMask[index]=cMask;
1@i/N bAdded=TRUE;
=RAojoN KeyCount++;
WL?qulC}h1 break;
#r/5!*3 }
OZA^L;#> }
yb,X
}"Et return bAdded;
:| !5d{8S8 }
%=$Knc_!T^ //删除热键
BwrX.!M BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
o/ 7[
G {
wbvOf X BOOL bRemoved=FALSE;
|*DkriYY for(int index=0;index<MAX_KEY;index++){
HYL['B?Wid if(hCallWnd[index]==hWnd){
FmhAUe if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
4Y1dkg1y hCallWnd[index]=NULL;
E]}_hZU HotKey[index]=0;
0
vYG#S HotKeyMask[index]=0;
e^,IZ{ bRemoved=TRUE;
*(qj!U43 KeyCount--;
y` {|D* break;
jz]}%O }
*tv\5KW G }
~FQHT?DAo }
]s!id[j return bRemoved;
Y`(~eNX^% }
?rA3<j /]U;7) {> <1K6t DLL中的钩子函数如下:
z~==7:Os ve:Oe{Ie{ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
wph8ln"C- {
`HO]
kJpX BOOL bProcessed=FALSE;
$7W5smW/ if(HC_ACTION==nCode)
!v(^wqna\ {
\<\H1;=.@' if((lParam&0xc0000000)==0xc0000000){// 有键松开
B:Ft(, switch(wParam)
X6T[+]Gc {
IUDH"~f case VK_MENU:
|a
a\t MaskBits&=~ALTBIT;
_/'VD!(MV break;
H
XFY case VK_CONTROL:
\I-e{'h MaskBits&=~CTRLBIT;
N/ ' break;
tC(Ma I case VK_SHIFT:
>*opE I+ MaskBits&=~SHIFTBIT;
\*'@F+ break;
Jm#p!G+ default: //judge the key and send message
>3pT).wH|M break;
9_nbMs }
LnKgT1 for(int index=0;index<MAX_KEY;index++){
v+[S${ if(hCallWnd[index]==NULL)
S,ea[$_ continue;
)QRT/, ;c if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
W$2\GPJt {
PTLlLa85< SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
)Tp"l"(G bProcessed=TRUE;
l qwy5# }
bJ2>@|3* }
,msP(*qoI }
Rd5-ao4 else if((lParam&0xc000ffff)==1){ //有键按下
dP(.l}O switch(wParam)
6wj o:I {
$5.52 case VK_MENU:
}(
CYok MaskBits|=ALTBIT;
-CuuO=h break;
71Za!3+ case VK_CONTROL:
}Hq3]LVE MaskBits|=CTRLBIT;
6W{Nw< break;
od5nRb case VK_SHIFT:
/}
z9( MaskBits|=SHIFTBIT;
fP5i3[T break;
3)ox8,{%} default: //judge the key and send message
?jUgDwc(w break;
[Z"Z5e` }
`B4Ilh"d for(int index=0;index<MAX_KEY;index++){
`4snTM!v& if(hCallWnd[index]==NULL)
xw_klHL-o continue;
i&^JG/a if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
:$k1I-^R {
2uN3:_w SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
- _8-i1? bProcessed=TRUE;
XHj%U }
>r7PK45.K }
8s2y!pn7Q }
_u^3uzu if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
[j5+PV for(int index=0;index<MAX_KEY;index++){
:Ae#+([V if(hCallWnd[index]==NULL)
6H:
fg continue;
.\T!oSb4[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
3@\/5I xn SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
$Wj{B@k //lParam的意义可看MSDN中WM_KEYDOWN部分
8 yi#] 5`Q }
}T(=tfv@ }
cZ|NGkZ }
&g&,~Y/z; return CallNextHookEx( hHook, nCode, wParam, lParam );
~cSXBc,+ }
j0~am,yZ M1Ff ,]w 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
uA[
: }xt^}:D BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
bRyxP2 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
<=GZm}/]N k<Gmb~Tg1 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
0$c(<+D b way+lh LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
HVoPJ!K3 {
ZCj1Cz]"l< if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
><D2of| {
iTq&h=(n //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
0C%IdV%CU SaveBmp();
Z81;Y=( return FALSE;
#J3o~,t< }
B
E8_.> …… //其它处理及默认处理
}(!Uq }
B-w`mcqp$ {g1"{ _,60pr3D' 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。
dWkQ NFKF IMbF]6%p( 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。
aWJ
BYw6{L c8[kL$b;j 二、编程步骤
68h1Wjg:"! y7:f^4 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
'+{yg+#/wV 9q$^x/z! 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
Xwo+iZ(a s<# BxN 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;
O&aD]~| DoFe:+_U3 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;
mxF+Fp~ )@I] Rk? 5、 添加代码,编译运行程序。
~<<32t'S: TA/hj>rV 三、程序代码
W[DoQ @q \^9n&MonM ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
WO9vOS> #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
"IQYy~
/ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
:Ob^b3<t #if _MSC_VER > 1000
cq?,v?m #pragma once
~D}fy #endif // _MSC_VER > 1000
AEnkx!o #ifndef __AFXWIN_H__
v&;JVai #error include 'stdafx.h' before including this file for PCH
u(8{5"C #endif
;}f {o^ ]' #include "resource.h" // main symbols
7K.],eo0 class CHookApp : public CWinApp
"#gKI/[qxq {
BaI-ve public:
ga\s5
CHookApp();
tzd!r7 // Overrides
[Q8Wy/o
Q // ClassWizard generated virtual function overrides
Hpz1Iy@ //{{AFX_VIRTUAL(CHookApp)
m?yztm~u public:
w<THPFFF" virtual BOOL InitInstance();
{ixKc virtual int ExitInstance();
HU/4K7e` //}}AFX_VIRTUAL
G7`mK}J7 //{{AFX_MSG(CHookApp)
q({-C // NOTE - the ClassWizard will add and remove member functions here.
w/ZP.B // DO NOT EDIT what you see in these blocks of generated code !
TAOsg0 //}}AFX_MSG
OhN2FkxL DECLARE_MESSAGE_MAP()
^4,LIIUj };
DeW{#c6 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
! jApV BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
1>\V>g9 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
u@:[ dbJ BOOL InitHotkey();
4zhh**]B BOOL UnInit();
'j{o!T0 #endif
Hp ;$fQ K/Y"oQ2 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
iuXXFuh #include "stdafx.h"
o-&0_Zq_ #include "hook.h"
p>J@"?%^ #include <windowsx.h>
(U$;0` #ifdef _DEBUG
N<4 nb #define new DEBUG_NEW
98
NFJ #undef THIS_FILE
V8WSJ=-&
static char THIS_FILE[] = __FILE__;
AZik:C"Q #endif
[+W<;iep #define MAX_KEY 100
Yc6.v8a #define CTRLBIT 0x04
~;]zEq-hG #define ALTBIT 0x02
Z
Q*hrgQ #define SHIFTBIT 0x01
=a+
} 6 #pragma data_seg("shareddata")
m}D;=>2$ HHOOK hHook =NULL;
-~JYfj@ UINT nHookCount =0;
- e0[$v static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
:|ahu static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
J9XH8Grk- static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
ojm IEzsz static int KeyCount =0;
#1*7eANfr static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
Yd~J( #pragma data_seg()
IaOR%Bg HINSTANCE hins;
stW
G`>X void VerifyWindow();
K8[Um!( BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
g2==`f!i //{{AFX_MSG_MAP(CHookApp)
[742s]j // NOTE - the ClassWizard will add and remove mapping macros here.
>)diXe}j // DO NOT EDIT what you see in these blocks of generated code!
A1Uy|Dl //}}AFX_MSG_MAP
2)0J@r' END_MESSAGE_MAP()
tEo-Mj5: :HrFbq CHookApp::CHookApp()
?>V>6cDQ {
!kb:g]X // TODO: add construction code here,
I][&*V1 // Place all significant initialization in InitInstance
Np$&8v+en }
S!gzmkGcj dXM8iP CHookApp theApp;
d@a<Eq LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
/|H9Gm {
a(?)r[= BOOL bProcessed=FALSE;
(.Ak* if(HC_ACTION==nCode)
Dyo^O=0c {
Uzrf,I[ if((lParam&0xc0000000)==0xc0000000){// Key up
84e8z { switch(wParam)
#6D>e~>n {
C'gv#!Q case VK_MENU:
kkb+qo MaskBits&=~ALTBIT;
/hVwrt( break;
]&D=*:c case VK_CONTROL:
3}mg7KV& MaskBits&=~CTRLBIT;
ir{
4k break;
I
2OQ case VK_SHIFT:
IDos4nM27] MaskBits&=~SHIFTBIT;
yk5K8D[tV break;
2.MUQ;OX default: //judge the key and send message
m0h,! break;
BaIuOZ@, }
Qhc;Zl for(int index=0;index<MAX_KEY;index++){
+U_1B%e(% if(hCallWnd[index]==NULL)
uCuB>x& continue;
LdNpb;* if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
p-EU"O {
TKGaGMx6@ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
G'w!Aw s bProcessed=TRUE;
fXl2i]L(^B }
>D~8iuy]8. }
@0t[7Nv-1 }
C^B$_? else if((lParam&0xc000ffff)==1){ //Key down
Lq;iR switch(wParam)
<BZC5b6 {
L1(-xNUo_i case VK_MENU:
GU@#\3 MaskBits|=ALTBIT;
z;<~j=lP break;
E7@Gpu,o case VK_CONTROL:
lfC]!=2%~8 MaskBits|=CTRLBIT;
!P^Mo> " break;
]plp.f#av case VK_SHIFT:
zP2X}VLMo MaskBits|=SHIFTBIT;
qsbo"29 break;
Mb\(52`)Q default: //judge the key and send message
NqOX);'L0 break;
} -;)G~h/" }
]Z6? m for(int index=0;index<MAX_KEY;index++)
oxL<\4)WJ {
ZOa| lB (, if(hCallWnd[index]==NULL)
BQg3+w:> continue;
c6c@XdV if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Y2.zT6i {
X_@|+d SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
?#Z4Dg
9| bProcessed=TRUE;
I{[Z
}
+ls`;f }
G'-#99wv. }
- PSgBH[ if(!bProcessed){
pXN'vP for(int index=0;index<MAX_KEY;index++){
Q{950$)L if(hCallWnd[index]==NULL)
C:5d/9k continue;
G&1bhi52 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
+> !nqp SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Z/?{{}H+ }
7/QK"0 }
we^'R}d }
L{8_6s(: return CallNextHookEx( hHook, nCode, wParam, lParam );
z5M6 }
m=^]93+ &b5(Su BOOL InitHotkey()
5~IdWwG*w {
u|Mx} if(hHook!=NULL){
z
rSPa\M nHookCount++;
-/{FGbpR; return TRUE;
bl^Ihza }
v=lW5%r,' else
Y01!D"{\ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
XJ3sqcS if(hHook!=NULL)
pUqC88*j nHookCount++;
=%IyR return (hHook!=NULL);
\-;f<%+ }
0: hv6Ge^ BOOL UnInit()
0`c{9gY. {
r W[;3yMf
if(nHookCount>1){
(M$>*O3SR nHookCount--;
!.mR]El{K return TRUE;
J$1H3#VVG }
o68i0aFW BOOL unhooked = UnhookWindowsHookEx(hHook);
E;C{i if(unhooked==TRUE){
*1`X} nHookCount=0;
}p2iF2g9` hHook=NULL;
~d]v{<3 }
a!: N
C return unhooked;
LiT%d }
#d\&6'O ..u{v}4& BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
H2R3I<j {
"*t6KXVaM BOOL bAdded=FALSE;
qovsM M for(int index=0;index<MAX_KEY;index++){
<.4(#Ebd if(hCallWnd[index]==0){
N?vb^? hCallWnd[index]=hWnd;
Vl5>o$G|<. HotKey[index]=cKey;
bGeIb-|( HotKeyMask[index]=cMask;
B1nm?E 0i bAdded=TRUE;
$]E+E.P KeyCount++;
nI6ompTX break;
8Zsaq1S }
\~%+)a%% }
zs#-E_^%M return bAdded;
!9/`PcNIpy }
J3
Q_ T@yQOD7 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
JnBc@qnP6 {
<<MpeMi BOOL bRemoved=FALSE;
iXnXZ|M for(int index=0;index<MAX_KEY;index++){
LsERcjwwK if(hCallWnd[index]==hWnd){
ekyCZ8iai if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
08nh y[ hCallWnd[index]=NULL;
jerU[3 HotKey[index]=0;
6Oy:5Ps8a HotKeyMask[index]=0;
$"/l*H\h bRemoved=TRUE;
:gwmk9LZ KeyCount--;
q\o#<'F1J break;
2w7$"N }
Zio!j%G }
Y`ip.Nx }
*%;A85V/ return bRemoved;
9S]pC?N]E }
~&)\8@2 U%:%. Bys void VerifyWindow()
Ljz)%y[s {
?l6yLn5si^ for(int i=0;i<MAX_KEY;i++){
'W_NRt: if(hCallWnd
!=NULL){ 4%r?(C0x
if(!IsWindow(hCallWnd)){ VX.LL
5
hCallWnd=NULL; .2@T|WD!Ah
HotKey=0; +-'F]?DN'
HotKeyMask=0; ^aAs=KditO
KeyCount--; $EFS_*<X
} ?{TWsuP7
} 2: gh q
} PxrT@.T$
} h7E?7nR
a8T9=KY^
BOOL CHookApp::InitInstance() qLLrR,:
{ k(H]ILL
AFX_MANAGE_STATE(AfxGetStaticModuleState()); wGLMLbj5
hins=AfxGetInstanceHandle(); -rcEG!
InitHotkey(); _WWC8?6U
return CWinApp::InitInstance(); 3 twA5)v
} 4utwcXL
jq)Bj#'7
int CHookApp::ExitInstance() _@B?
{ _?"y1L.
VerifyWindow(); h<&GdK2U+
UnInit(); [ x{$f7CEh
return CWinApp::ExitInstance(); /a32QuS
} u|IS7>Sm
m^L !_~
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file |E6_TZ#=
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) x@43ZH_
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ Q9OCf"n $
#if _MSC_VER > 1000 h!SsIy(
#pragma once `:3nF'
#endif // _MSC_VER > 1000 kB@gy}
%|H]T]s
class CCaptureDlg : public CDialog eowwN>-2C
{ b(N\R_IQ~
// Construction QD%xmP
public: bh5D}w
BOOL bTray; }6a}8EyFP
BOOL bRegistered; "v?F4&\ 8
BOOL RegisterHotkey(); If'2
m_
UCHAR cKey; NL:-3W7vf
UCHAR cMask; 8zeeC
eI U
void DeleteIcon(); 6ZE`'pk<
void AddIcon(); \ejHM}w3,
UINT nCount; tcoG;ir
void SaveBmp(); 0e0)1;t\
CCaptureDlg(CWnd* pParent = NULL); // standard constructor ^dLu#,;
// Dialog Data >D u=(pB
//{{AFX_DATA(CCaptureDlg) cy@Ri#
enum { IDD = IDD_CAPTURE_DIALOG }; eef&ZL6g
CComboBox m_Key; >(P(!^[f
BOOL m_bControl; Zfk]Z9YO
BOOL m_bAlt; G8vDy1`q6
BOOL m_bShift; I\_2=mL
CString m_Path; r}qDvC D
CString m_Number; ( gg )?
//}}AFX_DATA (y;
6H
// ClassWizard generated virtual function overrides a6vej
//{{AFX_VIRTUAL(CCaptureDlg) |Io:D:
public: }&/>v' G
virtual BOOL PreTranslateMessage(MSG* pMsg); U%bm{oVn
protected: &C