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:
z\YIwrq3*
oFY!NMq}: 一、实现方法
ON ?Y
Df D$>_W ,*V 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
,pNx(a 5pO|^Gj1 #pragma data_seg("shareddata")
>.h:Y5 HHOOK hHook =NULL; //钩子句柄
,Z.sGv UINT nHookCount =0; //挂接的程序数目
4
1_gak; static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
*O?c~UJhhV static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
_n&Nw7d2
M static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
ngY%T5- static int KeyCount =0;
&)eg3P)7 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
?RRO #pragma data_seg()
^;C& rg/{5f 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
DwD$T%kF b7Y g~Lw 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:
?KT{H(rU R1jl <= BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
pYO =pL^Q cKey,UCHAR cMask)
'CLZ7pV {
qnm_#!&uHT BOOL bAdded=FALSE;
(8 nv&| for(int index=0;index<MAX_KEY;index++){
h}b:-a if(hCallWnd[index]==0){
xNz(LZ.c hCallWnd[index]=hWnd;
#-hO\
QdC HotKey[index]=cKey;
v=`yfCX-qX HotKeyMask[index]=cMask;
x2"iZzQlD bAdded=TRUE;
8:cbr/F< KeyCount++;
H=dIZ break;
?^|`A}q# }
4aayMS!# }
Hl*vS return bAdded;
^xo<$zn }
.nV2n@SR //删除热键
>J"IN I BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
5/H,UL {
,'#TdLe BOOL bRemoved=FALSE;
|dRVSVN for(int index=0;index<MAX_KEY;index++){
3"fDFR if(hCallWnd[index]==hWnd){
Et>#&Nw8 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
qTO6I5u hCallWnd[index]=NULL;
OLw]BJXYaE HotKey[index]=0;
xm'9n? HotKeyMask[index]=0;
.Po"qoGy bRemoved=TRUE;
_vQ52H, KeyCount--;
j;x()iZ< break;
ez4!5&TzRm }
P<<$o-a" }
#h5:b`fDF }
t0)1;aBZ return bRemoved;
8`=?_zF }
'r;mm^cS? O"m7r ds b0P3S!E DLL中的钩子函数如下:
dBWny& b
F=MQ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
s.3"2waZ=T {
3G})$y3m BOOL bProcessed=FALSE;
,5DJ54B! if(HC_ACTION==nCode)
b|#=kPVgL} {
]TV_p[L0B if((lParam&0xc0000000)==0xc0000000){// 有键松开
'C+cQLig@ switch(wParam)
pP<8zTLn {
c{#2;k
Q, case VK_MENU:
/qpSmRL MaskBits&=~ALTBIT;
h$S#fY8 break;
=bKDD<( case VK_CONTROL:
R|;BO:S1 MaskBits&=~CTRLBIT;
1#vy# ' break;
}$6L]
case VK_SHIFT:
oOFTQB_6 MaskBits&=~SHIFTBIT;
nep#L>LP$x break;
;\MWxh,K default: //judge the key and send message
XqH@3Ehk break;
^W |YE72Y }
kUT2/3Vi for(int index=0;index<MAX_KEY;index++){
K;K0D@>]HR if(hCallWnd[index]==NULL)
6Yai?*.Q continue;
;?h[WIy if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
L G}{ibB {
xJq|,":gj SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
q8 v iC| bProcessed=TRUE;
qpQ;,8X-" }
iO L$| Z( }
l{By]S }
RQ+, 7Ir else if((lParam&0xc000ffff)==1){ //有键按下
!V|{(>+< switch(wParam)
}1a}pm2p {
["Zvwes#7 case VK_MENU:
G|i0n
MaskBits|=ALTBIT;
\S}/2]* 1 break;
zAgX{$/Fg case VK_CONTROL:
Z0gtliJ@ MaskBits|=CTRLBIT;
Y;'<u\^M" break;
D
0Xl`0"' case VK_SHIFT:
(
eV,f MaskBits|=SHIFTBIT;
*&U~Io"U break;
*>fr'jj1$ default: //judge the key and send message
$b8[/], break;
{!,K[QwcI }
?Uql30A for(int index=0;index<MAX_KEY;index++){
l4C{LZ if(hCallWnd[index]==NULL)
_!xrBdaJ continue;
8ud12^s$ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
HoI6(t {
*WE8J#]d SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Q%e<0t7 bProcessed=TRUE;
?m7:@GOE1 }
T(|'.&a }
I~,.@{4 }
S^O9}<2g if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
YQ0#j'}/ for(int index=0;index<MAX_KEY;index++){
^[<BMk if(hCallWnd[index]==NULL)
Pnytox continue;
qxZIH if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
y)kxR SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
y-<.l=6A //lParam的意义可看MSDN中WM_KEYDOWN部分
q,v<:sS9T }
QM,#:m1o }
{}$9
70y }
/=2aD5r return CallNextHookEx( hHook, nCode, wParam, lParam );
_p$/.~Xo9 }
_^ hg7&dF W>3S%2d 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:
-^&=I3bp z/t|'8f BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
<2U#U; BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
7q0_lEh (/y8KG3 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:
.Fb#j+Lq J 8i;E4R LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
4v[y^P {
_i_='dsyW/ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
Cqd\n#d/~ {
@9/I^Zk //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
PV68d; $:8 SaveBmp();
ki1(b]rf return FALSE;
x0 j5D }
'9\cIni0 …… //其它处理及默认处理
v9(5HY }
RZ6y5 rr#nBhh8 9r%fBiSk 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
"i&)+dr- B{Q}^Mcxy 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
<rC%$tr
PMjNc_)) 二、编程步骤
U[C>Aoze 5|*{~O| 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";
d4o
^+\ 2A_1 E\ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
MQ,K%_m8 Hq.rG-,p 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;
eV7;#w<] Vr2A7kq 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;
gP_N|LuF" 0ix(1`Z 5、 添加代码,编译运行程序。
>u= "FHJ_$! 三、程序代码
C?qRZB+W# xG!~TQ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
6_mi9_w #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
h<9vm[ . #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
w/@ZPBRo] #if _MSC_VER > 1000
n#!c!EfG #pragma once
}s,NM%oI #endif // _MSC_VER > 1000
#]h
X."b2 #ifndef __AFXWIN_H__
F
~A$7 #error include 'stdafx.h' before including this file for PCH
Jg#0g
eU #endif
i(~DhXz*T #include "resource.h" // main symbols
BTAbDyH5 class CHookApp : public CWinApp
h)Y] L#R {
3IxC@QR public:
t/|0"\ p CHookApp();
|[],z 8 // Overrides
t/ \S9 // ClassWizard generated virtual function overrides
a1pp=3Pd?~ //{{AFX_VIRTUAL(CHookApp)
@i ~ A7L0/ public:
UPtj@gtcY virtual BOOL InitInstance();
~z^?+MgZ2 virtual int ExitInstance();
I\*6
> //}}AFX_VIRTUAL
%ap(=^|5 //{{AFX_MSG(CHookApp)
SkuR~! // NOTE - the ClassWizard will add and remove member functions here.
b<FE
// DO NOT EDIT what you see in these blocks of generated code !
('x]@ //}}AFX_MSG
4,y7a=qf3 DECLARE_MESSAGE_MAP()
f*%kHfaXgN };
!Yof%%m$; LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
X>I3N?5 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
AJyNlQ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
W.3b]zcV BOOL InitHotkey();
T0 K!Msz BOOL UnInit();
2^[dy>[y0 #endif
tz;3 1ksFxpE //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
UZ<K'H,q #include "stdafx.h"
;JxL>K( #include "hook.h"
q,Gymh; #include <windowsx.h>
puPI^6y% #ifdef _DEBUG
>/ay'EyY;> #define new DEBUG_NEW
Zn9tG:V #undef THIS_FILE
8-#kY}d. static char THIS_FILE[] = __FILE__;
m>=DJ{KQ #endif
SKC;@? #define MAX_KEY 100
DS?.'"n[u #define CTRLBIT 0x04
4iA F<|6s #define ALTBIT 0x02
:#:|:q.] #define SHIFTBIT 0x01
3\W/VBJJ #pragma data_seg("shareddata")
hs7!S+[.$$ HHOOK hHook =NULL;
N
sdpE?V UINT nHookCount =0;
}y6)d. static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
@43psq1 static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
<,CrE5Pl static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
N3"Jo uP static int KeyCount =0;
<0d2{RQ; static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
G*z\
^H #pragma data_seg()
qyM/p.mP HINSTANCE hins;
J>(X0@eWz void VerifyWindow();
a&>NuMDI BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
QIiy\E% //{{AFX_MSG_MAP(CHookApp)
h0<PQZJ // NOTE - the ClassWizard will add and remove mapping macros here.
?^voA.Bv< // DO NOT EDIT what you see in these blocks of generated code!
d,GOP_N8I //}}AFX_MSG_MAP
"3^tVX%$\[ END_MESSAGE_MAP()
X['9;1Xr 6f +aGz CHookApp::CHookApp()
f<8Hvumw {
lpG%rN! // TODO: add construction code here,
~N!HxQ // Place all significant initialization in InitInstance
k6C XuU }
'xH^ksb " `X<B+:>v- CHookApp theApp;
>Y>R1b% LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
JP8}+ {
Et3I(X3 BOOL bProcessed=FALSE;
}JFTe
g if(HC_ACTION==nCode)
t5{P'v9J {
@v2<T1UC if((lParam&0xc0000000)==0xc0000000){// Key up
EHUx~Q
switch(wParam)
Z:9 Q~}x8 {
{R_>KE1 case VK_MENU:
gGMfy]]R MaskBits&=~ALTBIT;
6+$2rS$1V break;
-;9
}P case VK_CONTROL:
@HS*%N"* MaskBits&=~CTRLBIT;
*73gp
break;
c'2/ C5 case VK_SHIFT:
l@);U%\pS MaskBits&=~SHIFTBIT;
]s=|+tz\V break;
o-6d$c}{f default: //judge the key and send message
`<9>X9.+ break;
LGt>=|=bj }
4]r_K2.cc for(int index=0;index<MAX_KEY;index++){
H9)@q3<
if(hCallWnd[index]==NULL)
PCl5,]B} continue;
_)45G"M if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
O|H: {
&vrQ *jX SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
s70Z&3A bProcessed=TRUE;
DMUirA; }
+Kk1[fh-
}
0j@mzd2 }
;MN$.x+ else if((lParam&0xc000ffff)==1){ //Key down
T >8P1p@A, switch(wParam)
MhN;GMH {
-,")GA+[7 case VK_MENU:
t^'nh
1= MaskBits|=ALTBIT;
E !!,JnU break;
`/sNX<mp case VK_CONTROL:
&D3]O9a0; MaskBits|=CTRLBIT;
cUq]PC$| break;
P3"R2- case VK_SHIFT:
*
BM|luYL MaskBits|=SHIFTBIT;
Qxz[ break;
h
/ default: //judge the key and send message
LSta]81B4L break;
w*`:v$ }
z_>~=Mm for(int index=0;index<MAX_KEY;index++)
|mtW) {
C&z!="hMhR if(hCallWnd[index]==NULL)
D_lRYLA+ continue;
ox&5}&\ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
3%*igpj\) {
z 3aGK SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
%"`p&aE: bProcessed=TRUE;
jt}Re, }
xJ3C^b%H }
FQ>$Ps*a[ }
]ogifnwv if(!bProcessed){
$5pCfW8> for(int index=0;index<MAX_KEY;index++){
yv-R<c!' if(hCallWnd[index]==NULL)
uq3pk3
)W9 continue;
#}#m\=0 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
UPH#~D! SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
/MtmO$. }
[~N;d9H+*1 }
<);q,|eh2 }
q=t!COS return CallNextHookEx( hHook, nCode, wParam, lParam );
-jJhiaJ$< }
VgbNZ{qk@ ^t'mW;C$4 BOOL InitHotkey()
eJoM4v {
h8(#\E if(hHook!=NULL){
eKr>>4,-P nHookCount++;
KZ2[.[(Ph return TRUE;
3A,N1OXG }
d[t0K] else
_s;y0$O hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
Q# hRnM if(hHook!=NULL)
d&^b=d FDu nHookCount++;
P8m0]T.&x return (hHook!=NULL);
jV2H61d }
Z 7@'I0;A BOOL UnInit()
/<-PW9X? {
!*v%
s if(nHookCount>1){
OH@"]Nc~ nHookCount--;
44e]sT.B return TRUE;
k^}[+IFJ }
-f |/#1 BOOL unhooked = UnhookWindowsHookEx(hHook);
Yh95W if(unhooked==TRUE){
'bx}[
nHookCount=0;
=b%f@x_U1 hHook=NULL;
s:_hsmc" }
b%lB&}uw} return unhooked;
HwFg;r }
TFkG"ev PzPNvV/o BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
437Wy+Q|e {
9i\}^ s2 BOOL bAdded=FALSE;
Kyh6QA^ for(int index=0;index<MAX_KEY;index++){
z<eu=OD4t if(hCallWnd[index]==0){
K#A& hCallWnd[index]=hWnd;
<4TI;yy6? HotKey[index]=cKey;
Y@ v][Q HotKeyMask[index]=cMask;
0'd@8]|H bAdded=TRUE;
Vs5 &X+k KeyCount++;
SAnr|<Y/ break;
3X(^`lAf) }
ZSNbf|ldiE }
Vu(NP\Wm return bAdded;
6 :4GI }
| +;ZC y DG;u_6;JR BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
U,2OofLM {
St?mq* , BOOL bRemoved=FALSE;
D:9^^uVp for(int index=0;index<MAX_KEY;index++){
#<Y.+: if(hCallWnd[index]==hWnd){
Q%O9DCi if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
aX.BaK6I hCallWnd[index]=NULL;
KJFQ)#SW! HotKey[index]=0;
p>)1Z<D"a HotKeyMask[index]=0;
=+X*$'<J bRemoved=TRUE;
;,-)Z|W KeyCount--;
|Kd6.Mx break;
@ fMlbJq }
vE9"1M }
b#I,Z+0ry }
'\{ OQH return bRemoved;
HVvm3qu4 }
<uIPv
Zsx oRd{?I&NY void VerifyWindow()
>*!T`P}p {
@Xoh@:j\ for(int i=0;i<MAX_KEY;i++){
~jw:4sG if(hCallWnd
!=NULL){ No\#N/1@P
if(!IsWindow(hCallWnd)){ ( &m1*
hCallWnd=NULL; 5tv*uz|fv
HotKey=0; KeyKLkg>
HotKeyMask=0; 87[o^) 8
KeyCount--; w'}s'gGE
} ;7Qe m&
} xFUD9TM
} u&p8S#e
} Yy
4Was#
"a(R>PV%
BOOL CHookApp::InitInstance() ^Whc<>|
{ jEKa9rt
AFX_MANAGE_STATE(AfxGetStaticModuleState());
=pe O%
hins=AfxGetInstanceHandle(); 9I 6^-m@:
InitHotkey(); "^t7]=q
return CWinApp::InitInstance(); 4oF,;o+v\4
} 2^s@n3t
qb nlD\
int CHookApp::ExitInstance() 2;]tIt d1
{ vasw@Uto)
VerifyWindow(); toF6 Z
UnInit(); 'NWvQR<X
return CWinApp::ExitInstance(); BfCib]V9C
} ;\"Nekd|
fx 0 8>r
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file L,_U co
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) -C^qN7Bz
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ .~'q
yD2V
#if _MSC_VER > 1000 Ge$&