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:
N5~g:([k
R;,&CQUl 一、实现方法
*D|6g|Hb h`5au<h< 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:
P;A"`Il N\xqy-L9 #pragma data_seg("shareddata")
e[{LNM{/# HHOOK hHook =NULL; //钩子句柄
(hmasy6hM UINT nHookCount =0; //挂接的程序数目
I5 [r-r static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
=3& WH0 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
}3vB_0[r static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
&jg,8 static int KeyCount =0;
*h]qh20t static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
=D3Y
q? #pragma data_seg()
3`="4 g]d@X_ &D 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。
I.\u2B/? =0 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:
o_={xrmIA qWr`cO~hc BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
6 !+"7r6 cKey,UCHAR cMask)
ZtB0:'o; {
'6K WobXm BOOL bAdded=FALSE;
na/t=<{ for(int index=0;index<MAX_KEY;index++){
-h.']^I
if(hCallWnd[index]==0){
La3f{;|u5M hCallWnd[index]=hWnd;
|w\D6d]o HotKey[index]=cKey;
85nUR[)h HotKeyMask[index]=cMask;
F\>`j bAdded=TRUE;
m6g+ B > KeyCount++;
|!&,etu break;
d~28!E+ }
Hm4lR{A
}
Tm`QZh3 return bAdded;
g,Q!F }
{Y\hr+A //删除热键
3+!N[6Od9 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Ue-HO {
:Z`4ea"w BOOL bRemoved=FALSE;
U,g!KN3P for(int index=0;index<MAX_KEY;index++){
%f,
9 if(hCallWnd[index]==hWnd){
+mAMCM2N if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
T@k&YJ
hCallWnd[index]=NULL;
t6js@Ih HotKey[index]=0;
\r<&7x#j HotKeyMask[index]=0;
] niWRl bRemoved=TRUE;
!fz`O>-mZ KeyCount--;
qr6WSBc break;
'3|OgV }
@tp/0E? }
>-oa`im+ }
[[TB.'k return bRemoved;
xazh8X0P }
zwAuF%U YS~\Gls% 7b
Gzun& DLL中的钩子函数如下:
e2Xx7*vS m#8KCZS LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
)vy<q/o+ {
%yptML9 BOOL bProcessed=FALSE;
,riwxl5*E/ if(HC_ACTION==nCode)
IK}T.*[ {
Fbk<qQH if((lParam&0xc0000000)==0xc0000000){// 有键松开
yP[GU| >( switch(wParam)
R2M,VK?Wx {
[IW@mn> case VK_MENU:
E1VCm[j2 MaskBits&=~ALTBIT;
?F`lI""E break;
hRA.u'M case VK_CONTROL:
d(fgv MaskBits&=~CTRLBIT;
6x -PGq break;
j*+r`CX case VK_SHIFT:
]`u{^f
MaskBits&=~SHIFTBIT;
yv'mV=BMJ! break;
v[lytX4) default: //judge the key and send message
`D#l(gZ break;
6"%[s@C }
e {c.4'q for(int index=0;index<MAX_KEY;index++){
+ E S.O]?> if(hCallWnd[index]==NULL)
9|'bPOKe continue;
VgoQz]z if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
g"zk14' {
$SXF>n{} SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Ke,-8e#Q bProcessed=TRUE;
Oq! u `g9 }
MTqbQ69v }
%DRDe }
w7%N=hL1 else if((lParam&0xc000ffff)==1){ //有键按下
s/A]&!` switch(wParam)
R~c(^.|r {
J-X5n 3I& case VK_MENU:
]enqkiS MaskBits|=ALTBIT;
!!` zz break;
O<%U*:B case VK_CONTROL:
0<>iMr D MaskBits|=CTRLBIT;
gXf_~zxS break;
40@KL$B= case VK_SHIFT:
m]u#Dm7h MaskBits|=SHIFTBIT;
h`n>6I break;
i%\nJs* default: //judge the key and send message
fWLsk break;
%%-kUe }
zpa'G1v for(int index=0;index<MAX_KEY;index++){
X\$M _b>O if(hCallWnd[index]==NULL)
W>@+H"pZ continue;
=`/X
Wem if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
eyo )Su {
"@ox= SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
uCUBs(iD bProcessed=TRUE;
o-x_[I|@ }
6J=~ *& }
fA+M/}= }
A 4&e# if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
z?7s'2w&{ for(int index=0;index<MAX_KEY;index++){
Rx'7tff%I if(hCallWnd[index]==NULL)
4CN8>J'- continue;
zu;Yw=cM) if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
C g&1 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
wOa_" //lParam的意义可看MSDN中WM_KEYDOWN部分
,*C^ixNE }
1,pg:=N9 }
OB"QWdh }
tKJ)'v? return CallNextHookEx( hHook, nCode, wParam, lParam );
g@j:TQM_0 }
{8"W esLY1c%"/ 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:
m\~[^H~g #b8/gRfS BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
t@4vEKw?.X BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
E8-p
,e, "#m*`n 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:
w=f8UtY9@A ^Xb!dnT.*a LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
JP@UvDE| {
p=r{ODw#3 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
5-&P4 {
j+Tk|GRab //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
C8{CKrVE SaveBmp();
e`_3= kI return FALSE;
V];RQWs }
.y'OoDe …… //其它处理及默认处理
K}$PI W }
bqLv81 V ]_-$ &V2G<gm0 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。
Z1OcGRN! gr-%9=Uq 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。
(/N`Wu ?9PNCd3$d 二、编程步骤
k} <mmKB &E9%8Q)r( 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";
l_kH^ET [Zua7&( 5 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
9PR&/Q
F5 RGxOb 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;
~MQN& ?Ts
Z_ 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;
S63L>p|ml ~ 01]VA 5、 添加代码,编译运行程序。
82w<q( ___+5r21\ 三、程序代码
XBeHyQp "n05y} ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
km3-Hp1 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
xbmOch}j6 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
VSSiuo'5w #if _MSC_VER > 1000
;j52a8uE'} #pragma once
=|G PSRQ #endif // _MSC_VER > 1000
5N[Y2 #ifndef __AFXWIN_H__
}k,Si9O #error include 'stdafx.h' before including this file for PCH
*'`-plS7 #endif
ho:,~ A;k #include "resource.h" // main symbols
a<HM|dcst class CHookApp : public CWinApp
^7_<rs {
'i@Y #F%D public:
>MhkNy CHookApp();
dA_s7), // Overrides
T // ClassWizard generated virtual function overrides
Sa@Xh,y Z //{{AFX_VIRTUAL(CHookApp)
\[8I5w- public:
%8$wod6 virtual BOOL InitInstance();
pFG~XW virtual int ExitInstance();
>4ALF[oH1J //}}AFX_VIRTUAL
]9x30UXLwD //{{AFX_MSG(CHookApp)
aH>.o 1; // NOTE - the ClassWizard will add and remove member functions here.
55[K[K // DO NOT EDIT what you see in these blocks of generated code !
>
h:~*g //}}AFX_MSG
MZ+"Arzb DECLARE_MESSAGE_MAP()
$MR{3- };
EM([N*8o
LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
gReaFnm BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
8EP^M~rv BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
RZz] .Nx BOOL InitHotkey();
C( r?1ma BOOL UnInit();
2Hq!YsJ4] #endif
c(eu[vj: ricDP 9#a //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
>uUbWKn3 #include "stdafx.h"
0_Y;r{3m" #include "hook.h"
#ob">R #include <windowsx.h>
jUfc&bi3 #ifdef _DEBUG
>M +!i+ #define new DEBUG_NEW
(*M(gM{; #undef THIS_FILE
8,H static char THIS_FILE[] = __FILE__;
6Es-{u(, #endif
lc'Jn$O@ #define MAX_KEY 100
}LE/{]A #define CTRLBIT 0x04
y%T'e(5Ed #define ALTBIT 0x02
9> (8r+ #define SHIFTBIT 0x01
M2m@N-+R
#pragma data_seg("shareddata")
",K6zALJ HHOOK hHook =NULL;
w)}[)}T! UINT nHookCount =0;
%iX+" static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
8
{QvB"w static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
=6%0pu]0 static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
Eu0_/{: static int KeyCount =0;
8d>OtDLa static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
3|~(9b{+ #pragma data_seg()
<ZnAPh HINSTANCE hins;
t<`BaU void VerifyWindow();
OgzPX^q/= BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
?Jx8z`( //{{AFX_MSG_MAP(CHookApp)
MqNp*n2 // NOTE - the ClassWizard will add and remove mapping macros here.
gFW1Nm_DJ // DO NOT EDIT what you see in these blocks of generated code!
PgxU;N7Y //}}AFX_MSG_MAP
0ogTQ`2Z: END_MESSAGE_MAP()
9x:c"S* $w65/ CHookApp::CHookApp()
:|d3BuY {
b _6j77 // TODO: add construction code here,
%f^TZ,q$ // Place all significant initialization in InitInstance
|w:\fK[ }
DsP+#PX >uI|S CHookApp theApp;
UZdpKi@ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
38f9jF%7j {
dM$]OAT BOOL bProcessed=FALSE;
_E?(cWC if(HC_ACTION==nCode)
"V^(i%E; {
'g$|:bw/ if((lParam&0xc0000000)==0xc0000000){// Key up
.m4K ]^m switch(wParam)
\BS^="AcpP {
0lW}l9}'- case VK_MENU:
x0 j$]$ MaskBits&=~ALTBIT;
g#H#i~E^ break;
p;C`n)7P7 case VK_CONTROL:
0z%]HlPg MaskBits&=~CTRLBIT;
6>KDK<5NQ break;
3ldOOQW% case VK_SHIFT:
-\r*D#aHBN MaskBits&=~SHIFTBIT;
VpD9!;S break;
"Z,'NL>& default: //judge the key and send message
iJ#sg+ break;
2.CI^.5& }
z*kn.sW for(int index=0;index<MAX_KEY;index++){
92S<TAdPP if(hCallWnd[index]==NULL)
CjD2FnjT continue;
*}LYMrP if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
#LcF;1o%o2 {
2!l)%F` SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
/#.6IV( bProcessed=TRUE;
=0O`VSb }
tcmG>^YM }
{@({po }
]ul]L
R%. else if((lParam&0xc000ffff)==1){ //Key down
eH75:` switch(wParam)
VFRUiz/C {
`L0}^|`9 case VK_MENU:
+A/n<VH MaskBits|=ALTBIT;
b}axw+ break;
S3.Pqp_< case VK_CONTROL:
#IgY'L MaskBits|=CTRLBIT;
)5p0fw break;
w+[r$+z!k case VK_SHIFT:
I>fEwMk~ MaskBits|=SHIFTBIT;
M$|^?U>cm break;
02b v0 default: //judge the key and send message
o-49o5:1 break;
?7(`2=J }
m~%IHWO' for(int index=0;index<MAX_KEY;index++)
{PdyKgM {
J6=*F;x6E if(hCallWnd[index]==NULL)
iN=-N=
continue;
N^:)U"9*e if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
bW[Y:}Hk~ {
cO_En`F SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
29}(l#S}m bProcessed=TRUE;
qm8[ ^jO& }
]iYjS }
td%EbxJK]` }
qm]k
(/w if(!bProcessed){
Y}ITA=L7 for(int index=0;index<MAX_KEY;index++){
IJ[#$I+Z% if(hCallWnd[index]==NULL)
z[[|'02{ continue;
1dHN<xy if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
"Q-TLN5( SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
f)/Yru. ; }
j<e`8ex? }
T =_Hd }
':6`M return CallNextHookEx( hHook, nCode, wParam, lParam );
&*A7{76x }
5Z1b9.;., Y!"LrkC BOOL InitHotkey()
QGn3xM66 {
9qIjs$g if(hHook!=NULL){
K+2<{qwh nHookCount++;
/ 9^:*, return TRUE;
FUiEayM }
0LeR#l:I else
Z;-=x p hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
|*K AqTO0 if(hHook!=NULL)
w+z~Mz}Vz nHookCount++;
Xu2:yf4No* return (hHook!=NULL);
"NMX>a,( }
7c5+8k3 BOOL UnInit()
jgK8} C {
.\".}4qQ if(nHookCount>1){
1T!(M"'Ij nHookCount--;
tp7cc;0 return TRUE;
Am{Vtl)i }
nj]l'~Y0 BOOL unhooked = UnhookWindowsHookEx(hHook);
T2Ms/1FH/@ if(unhooked==TRUE){
:bNqK0[rS nHookCount=0;
f#FAi3 hHook=NULL;
>kU$bh.( }
Gx,<|v return unhooked;
XOe)tz
L }
3"!h+dXw CD]"Q1
t} BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
ga%gu9 {
5%Hw,h BOOL bAdded=FALSE;
1P;J%.{ for(int index=0;index<MAX_KEY;index++){
#Ie/| if(hCallWnd[index]==0){
9kZ[Z
,=> hCallWnd[index]=hWnd;
+-"uJIwMD HotKey[index]=cKey;
d< j+a1& HotKeyMask[index]=cMask;
o"wvP~H bAdded=TRUE;
P'l'[Kz{' KeyCount++;
>BFUts% break;
R2,Z`I }
"{>BP$Jz }
w=JO$7 return bAdded;
%dn!$[D@ }
? DJ/Yw>>3 B6UTooj BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
2zE gAc {
tx`gXtO$ BOOL bRemoved=FALSE;
6Uh_&?\% for(int index=0;index<MAX_KEY;index++){
l5P!9P if(hCallWnd[index]==hWnd){
Z #uxa if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Q8|
C>$n hCallWnd[index]=NULL;
`O,^oD4 HotKey[index]=0;
c`,'[Q5(O HotKeyMask[index]=0;
_"l2UDx bRemoved=TRUE;
AcHr X=O KeyCount--;
$Iz *W]B! break;
'<=77yDg }
D*0[7:NSO }
qzk!'J3*r< }
>uLWfk+y1 return bRemoved;
nz2`YyR }
CWdpF>En t4d^DZDh! void VerifyWindow()
+khVi} {
z"%{SI^ for(int i=0;i<MAX_KEY;i++){
h[ cqa if(hCallWnd
!=NULL){ R,8 W7 3
if(!IsWindow(hCallWnd)){ He9Er
hCallWnd=NULL; 0?,<7}"<X
HotKey=0; 7?@ -|{
HotKeyMask=0; b9R0"w!ml
KeyCount--; do[w&`jw8
} zFi)R }Ot
} w<LV5w+
} ZyX+V?4
} {[pzqzL6
kxCN0e#_
BOOL CHookApp::InitInstance() .k -!/ ^
{ Cu!S|Xj.
AFX_MANAGE_STATE(AfxGetStaticModuleState()); }D]y-BbA.
hins=AfxGetInstanceHandle(); qDS~|<Y5
InitHotkey(); 5fq4[a
return CWinApp::InitInstance(); ~KYA{^`*
} 3~%M4(
<:>[24LJ{
int CHookApp::ExitInstance() SFjR SMi
{ 8;d./!|'&g
VerifyWindow(); ]T=o >%
UnInit(); )i"52!
return CWinApp::ExitInstance(); eRm*+l|?
} d(YAH@
B{K_?ae!
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file LJSx~)@
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) Z|B`n
SzH
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_
w~~[0e+E
#if _MSC_VER > 1000 *+%$OH,
#pragma once I6i qC"BK
#endif // _MSC_VER > 1000 siOyp]
*SYuq)
class CCaptureDlg : public CDialog vt#&YXu{A
{
qN'%q+n
// Construction -I:L6ft8
public: p^C$(}Yh
BOOL bTray; V#+M lN
BOOL bRegistered; z
$iI
BOOL RegisterHotkey(); 62o nMY
UCHAR cKey; 734H{,~
UCHAR cMask; m'KEN<)s
void DeleteIcon(); )0\D1IFJ
void AddIcon(); D1V^DbUm_
UINT nCount; n){u!z)Al
void SaveBmp(); "`V:4uz
CCaptureDlg(CWnd* pParent = NULL); // standard constructor m0*_
// Dialog Data 0?''v>%
//{{AFX_DATA(CCaptureDlg) ),@m
3wQ
enum { IDD = IDD_CAPTURE_DIALOG }; CpU
y~
CComboBox m_Key; ybcCq]cgt
BOOL m_bControl; $e%m=@ga
BOOL m_bAlt; !]MGIh#u
BOOL m_bShift; r@CbhD
CString m_Path; ^qtJcMK+hq
CString m_Number; [M?&JA