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:
A +)`ZTuO
zv"Z DRW 一、实现方法
x$%!U[!3 5PnDN\ 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
k;L6R!V D#)b+7N- #pragma data_seg("shareddata")
E+JqWR5 HHOOK hHook =NULL; //钩子句柄
V2G6Kw9gt UINT nHookCount =0; //挂接的程序数目
]$_NyAoBb static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
kSh( u static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
?F;8Pa/ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
GM<-&s!Uj static int KeyCount =0;
1sH&
sGy7 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
O7IJ%_A& #pragma data_seg()
8&aq/4:q0 k@:%:Sj 2 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。
Tu 7QCr5* v}Fr@0% 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:
JO<wU "w.3Q96r BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
&`XVq"7 cKey,UCHAR cMask)
?K\axf>F {
@y&bw9\ BOOL bAdded=FALSE;
t<viX's for(int index=0;index<MAX_KEY;index++){
}Z,x~G if(hCallWnd[index]==0){
IB7E}56l hCallWnd[index]=hWnd;
# Vha7 HotKey[index]=cKey;
Qz
N&>sk" HotKeyMask[index]=cMask;
E\,-XH bAdded=TRUE;
1y4 KeyCount++;
^`>/.gL break;
$p?aVO }
{!dVDf_ }
!I
Qck8Y return bAdded;
Y.r+wc] }
h2""9aP! //删除热键
5[u]E~Fl} BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
,WB{i^TD {
(*)hD(C5 BOOL bRemoved=FALSE;
b%/ 1$>_ for(int index=0;index<MAX_KEY;index++){
{jX2} if(hCallWnd[index]==hWnd){
Per1IcN if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
>J>[& zS hCallWnd[index]=NULL;
%- 0t?/> HotKey[index]=0;
;BIY^6,7e HotKeyMask[index]=0;
/RC7"QzL bRemoved=TRUE;
>&5DsV.B KeyCount--;
]wG{!0pl break;
NPe%F+X }
J~UuS+Ufv }
Tyf`j,= }
7VF LJrt return bRemoved;
YVanW }
'u b@]ru| .xWC{}7[ OH(waKq2I DLL中的钩子函数如下:
;VO:ph4Aj <<R*2b LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
b`O'1r\Y; {
DZPPJ2 } BOOL bProcessed=FALSE;
r?
E)obE if(HC_ACTION==nCode)
p2$P:!Y) {
8q}q{8 if((lParam&0xc0000000)==0xc0000000){// 有键松开
V /V9B2.$ switch(wParam)
UQ@L V~6{R {
?oHpFlj case VK_MENU:
u($!z^h MaskBits&=~ALTBIT;
R',rsGd`6j break;
^qD$z=z- case VK_CONTROL:
|2n4QBH! MaskBits&=~CTRLBIT;
Y\?"WGL)p break;
>e[i5 case VK_SHIFT:
@wNG{Stj MaskBits&=~SHIFTBIT;
6MMOf\
break;
OA"q[s default: //judge the key and send message
JB[~;nLlC break;
Hn+~5@. }
!NvI:C_4| for(int index=0;index<MAX_KEY;index++){
l3I:Q^x@ if(hCallWnd[index]==NULL)
dvJM6W>^= continue;
>_"an~Ss if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
|Uh {
"]b<uV SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
D!-g&HBTC bProcessed=TRUE;
FZslv"F }
<s<n }
S2GxV/E }
x Bi' X else if((lParam&0xc000ffff)==1){ //有键按下
.MoU1n{Yc switch(wParam)
")XHak.JX {
~;{;,8!) case VK_MENU:
G^4hd i3@ MaskBits|=ALTBIT;
'^~{@~ ;%L break;
65$+{s case VK_CONTROL:
nwRc%C``UK MaskBits|=CTRLBIT;
V7fq4O^: break;
"N bq#w\ case VK_SHIFT:
#-i>;Rt MaskBits|=SHIFTBIT;
UIN<2F_ break;
]{mPh\ default: //judge the key and send message
!/i{l break;
}.m< }
=QiI :|eRA for(int index=0;index<MAX_KEY;index++){
mQ26K~ if(hCallWnd[index]==NULL)
(b-MMr continue;
c>:wd@w if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
9} M?P {
Hp!-248 S SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
k],Q9 bProcessed=TRUE;
rgtT~$S }
=BAW[%1b }
ryUQU^v }
,,Q O^j]4~ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
3/e.38m| for(int index=0;index<MAX_KEY;index++){
7XLtN "$$ if(hCallWnd[index]==NULL)
-Xm'dwm continue;
RF4vtQC= if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
9FYUo SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
tKx~1- //lParam的意义可看MSDN中WM_KEYDOWN部分
:L@?2), }
l=)xo@6 }
n QZwC
}
hwBfdZ return CallNextHookEx( hHook, nCode, wParam, lParam );
9YQb& }
e+BQww Z|j>gq 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:
[KaAXv
.X P& -Qc BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
d#rf5<i BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
s;Z\Io tla
5B_ 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:
(G4at2YLd Ed,~1GanY LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{19PL8B~} {
1&evG-#<: if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
sRL`dEl4l {
>xYpNtEs //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
m6&~HfwN SaveBmp();
O/a4]r+_ return FALSE;
]kRfB:4ED }
J0\Fhe0' …… //其它处理及默认处理
uHvp;]/0\ }
lC("y'
:: a85$K$b> `nv~NLkl 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。
" H&W}N ex9g?*Q 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。
#9}D4i.`} D] jzAx 二、编程步骤
(%e.:W${ T?soJ]A 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
?2;&O`x* ag#S6E^%S 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
8Pn#+IvCE %x{kc3PnO 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
m=A(NKZ
>G*eNn 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
foF({4q7b^ %.Fi4}+O 5、 添加代码,编译运行程序。
i,E{f wQH<gJE/: 三、程序代码
)3Iz (Ql K>r,(zgVc ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
)=Z>#iH1 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
]J} #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
3kIN~/<R+7 #if _MSC_VER > 1000
zH4D 8@[7O #pragma once
?{|q5n #endif // _MSC_VER > 1000
\y)rt ) #ifndef __AFXWIN_H__
w\}ieI8J #error include 'stdafx.h' before including this file for PCH
|\<`Ib4j #endif
~'iHo]9O #include "resource.h" // main symbols
'()xHEGl3 class CHookApp : public CWinApp
}=UHbU.n~! {
E$:*NSXj public:
W*4-.*U8a CHookApp();
o"Euwh!!
// Overrides
O=&0 H|B // ClassWizard generated virtual function overrides
m!4ndO;0vh //{{AFX_VIRTUAL(CHookApp)
g\(G\ tnu> public:
S)k*?dQ##R virtual BOOL InitInstance();
*1
]uH e virtual int ExitInstance();
7he,?T)vD //}}AFX_VIRTUAL
D},>mfzF //{{AFX_MSG(CHookApp)
5k3n\sqZA // NOTE - the ClassWizard will add and remove member functions here.
?(y*nD[a // DO NOT EDIT what you see in these blocks of generated code !
|`f$tj //}}AFX_MSG
Z!#!Gu*V DECLARE_MESSAGE_MAP()
1N^[.= };
z8~NZ;A LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
#`iB`| BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
a|x.C6Pe BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
w d^': BOOL InitHotkey();
|zNX=mAV BOOL UnInit();
trA4R/
& #endif
OwUhdiG Ovt.!8 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
/y#f3r+*2 #include "stdafx.h"
Gg3,:A_ w #include "hook.h"
SSg8}m5)Q #include <windowsx.h>
N/'b$m5=
S #ifdef _DEBUG
} FlT%>Gw #define new DEBUG_NEW
OU(8V^. #undef THIS_FILE
eRstD>r static char THIS_FILE[] = __FILE__;
*74MWF@IY #endif
hh)`645=x #define MAX_KEY 100
vq0Tk
bzs #define CTRLBIT 0x04
qIE9$7*X #define ALTBIT 0x02
}J`w4P #define SHIFTBIT 0x01
]z;I_- #pragma data_seg("shareddata")
o>i4CCU+ HHOOK hHook =NULL;
R)(T^V`{ UINT nHookCount =0;
IH&|Tcf\ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
v0+BkfU+p static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
F>6|3bOR static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
,RI Gc US static int KeyCount =0;
)0W{]2 static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
f#"J]p #pragma data_seg()
#s(BuVU HINSTANCE hins;
y`5
9A void VerifyWindow();
YQ)kRhFA BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
4JXeV&5Qk' //{{AFX_MSG_MAP(CHookApp)
.x.]`b( // NOTE - the ClassWizard will add and remove mapping macros here.
6qpJUkd // DO NOT EDIT what you see in these blocks of generated code!
J26V nK //}}AFX_MSG_MAP
A_ZY=jP END_MESSAGE_MAP()
6f>{"' 9Cp-qA%t CHookApp::CHookApp()
;_I8^? d {
S-b/S5 // TODO: add construction code here,
EIAc@$4 // Place all significant initialization in InitInstance
TR`U-= jH, }
8)3*6+D (9GWbB? CHookApp theApp;
tBWrL{xLe LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
rmm0/+jY {
NiK4d{E& BOOL bProcessed=FALSE;
E \EsWb if(HC_ACTION==nCode)
glxsa8 {
~2N"#b&J if((lParam&0xc0000000)==0xc0000000){// Key up
J#(LlCs?@c switch(wParam)
j#x6
{
RFc v^Xf case VK_MENU:
fk>aqm7D! MaskBits&=~ALTBIT;
)
7@ `ut break;
rJTa case VK_CONTROL:
q5+4S5R*^ MaskBits&=~CTRLBIT;
$dC?Tl|B0 break;
EU;9*W< case VK_SHIFT:
>dD@j:Qc MaskBits&=~SHIFTBIT;
1{.|+S Z! break;
`?@}>. default: //judge the key and send message
u@M,qo` break;
]Sz:|%JP1 }
MYvY]Jx3 for(int index=0;index<MAX_KEY;index++){
'ya{9EdlT if(hCallWnd[index]==NULL)
yYYSeH continue;
^*Q ?]N if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
7"x;~X {
g%I"U>!2 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
xml7Uarc bProcessed=TRUE;
pRpBhm;iJ }
m,w A:o$' }
hEH?[>9 }
s`8= 3]w else if((lParam&0xc000ffff)==1){ //Key down
#L;dI@7C switch(wParam)
69NeQ$]( {
{duz\k2 case VK_MENU:
}C?'BRX MaskBits|=ALTBIT;
2\{M:\2o break;
7U"g3a)= case VK_CONTROL:
itP,\k7>d MaskBits|=CTRLBIT;
*#|&JIEsi break;
783,s_ case VK_SHIFT:
>T-u~i$s
MaskBits|=SHIFTBIT;
*n
]GsOOn break;
C2I_%nU Z1 default: //judge the key and send message
p%Vt#?q break;
&`r-.&Y }
LA5(sp@O for(int index=0;index<MAX_KEY;index++)
0i>5<ej,f {
4.aZ#c91_ if(hCallWnd[index]==NULL)
f~R(D0@ continue;
R+z2}}Z!` if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Y\P8v {
;[YG@-"XZ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
"+nRGEs6 bProcessed=TRUE;
cwlRQzQ( }
4e7-0}0 }
Iyn(?w }
#gN&lY:CFn if(!bProcessed){
bsli0FJSh' for(int index=0;index<MAX_KEY;index++){
_J#zY-j if(hCallWnd[index]==NULL)
lfgq=8d continue;
Qd{CMmx if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
;ef}}K SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
o:'MpKm }
GL}]y -f }
ec;o\erPG }
}R2u@%n{ return CallNextHookEx( hHook, nCode, wParam, lParam );
J]'zIOQ }
^uc=f2=>, G e@{_ BOOL InitHotkey()
`/+>a8 {
%aCqi(.7 if(hHook!=NULL){
^z*t%<@[Q nHookCount++;
Wvh#:Z return TRUE;
_4~+{l+ }
Q3~H{)[Kq else
Nh|uO?&C6 hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
; DR$iH-F if(hHook!=NULL)
t{9GVLZ nHookCount++;
\V63qg[ return (hHook!=NULL);
g:@#@1rB6 }
oZgjQM$YP BOOL UnInit()
h(dvZ=
% {
%wy.TN if(nHookCount>1){
h;"4+uw nHookCount--;
?l{nk5,?-Y return TRUE;
C{rcs' }
hi(;;C9 BOOL unhooked = UnhookWindowsHookEx(hHook);
2F.;;Ab if(unhooked==TRUE){
M7~2iU<# nHookCount=0;
9cF[seE"0 hHook=NULL;
]%H`_8<gc }
>tr}|> return unhooked;
cuITY^6 }
_TZRVa_ h438` BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
mq.`X:e {
C<tl/NC BOOL bAdded=FALSE;
bAqA1y3= for(int index=0;index<MAX_KEY;index++){
2%m BK if(hCallWnd[index]==0){
X+9>A.92 hCallWnd[index]=hWnd;
ZLejcYS HotKey[index]=cKey;
\M^bD4';> HotKeyMask[index]=cMask;
rM%1GPVob bAdded=TRUE;
4+8@`f>s KeyCount++;
{VRf0c break;
CHX #^0m. }
Wac&b }
XpHrt XD return bAdded;
%tGO?JMkd }
Bwxd&;E \R_C&= BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Ti5-6%~& {
r,p%U!S<hV BOOL bRemoved=FALSE;
-Q*gW2KmV for(int index=0;index<MAX_KEY;index++){
O^
yG?b if(hCallWnd[index]==hWnd){
24eLB?H if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
q0vQa hCallWnd[index]=NULL;
kDxFloK HotKey[index]=0;
u6JM]kR HotKeyMask[index]=0;
rEWb" bRemoved=TRUE;
}Sv:`9= KeyCount--;
Y$_B1_ break;
#\OA )`U }
~f98#43 }
kl:Bfs)b }
/U9"wvg return bRemoved;
f]CXu3w(J }
VTE .^EK! ;e *!S}C, void VerifyWindow()
%h!B^{0 {
sO@Tf\d for(int i=0;i<MAX_KEY;i++){
zrb}_ if(hCallWnd
!=NULL){ B]tQ(s~
if(!IsWindow(hCallWnd)){ (jE9XxQY
hCallWnd=NULL; )SGq[B6@I
HotKey=0; R\[e!g*I
HotKeyMask=0; /\n-P'}
KeyCount--; j\M?~=*w
} ?=Kduef
} > ~O.@|
} Gd85kY@w7
} NzvXN1_%
k<?b(&`J
BOOL CHookApp::InitInstance() -iZ`Y?
{ ckCE1e>s
AFX_MANAGE_STATE(AfxGetStaticModuleState()); ~t~|"u"P
hins=AfxGetInstanceHandle(); ;2QP7PrSY
InitHotkey(); T>W,'H
return CWinApp::InitInstance(); ]Y&VT7+Z
} +ZP7{%
5{,<j\#L
int CHookApp::ExitInstance() r~['VhI!;E
{ sW\!hW1*x
VerifyWindow(); 'I;zJ`Trd
UnInit(); $XH^~i;
return CWinApp::ExitInstance(); Eu3E-K@y
} xAm6BB
c
a%0EiU
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file QMm%@zH
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_)
[$UI8tV
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ t]G:L}AOl
#if _MSC_VER > 1000 X:{!n({r=
#pragma once @H8EWTZ
#endif // _MSC_VER > 1000 -KbYOb
!&E-}}<
class CCaptureDlg : public CDialog vl)l'
{ jPkn[W#
6
// Construction 8z\xrY
public: j?QDR
BOOL bTray; J'r^/
BOOL bRegistered; 8u]2xB=K
BOOL RegisterHotkey(); F!K>K z
UCHAR cKey; lyhiFkO
iH
UCHAR cMask; _aeBauD
void DeleteIcon(); Vxt+]5X
void AddIcon(); (QB2T2x
UINT nCount; MolgwVd
void SaveBmp(); )+Pus~w
CCaptureDlg(CWnd* pParent = NULL); // standard constructor 5"H=zJ=r
// Dialog Data \~ wMfP8
//{{AFX_DATA(CCaptureDlg) fc>L K7M
enum { IDD = IDD_CAPTURE_DIALOG }; M',?u
CComboBox m_Key; klhtKp_p
BOOL m_bControl; F:DrX_O%
BOOL m_bAlt; _)-o1`*-
BOOL m_bShift; \fe]c :
CString m_Path; q5S9C%b
CString m_Number; dAj$1Ke
//}}AFX_DATA ]]yO1x$Kk
// ClassWizard generated virtual function overrides I%Z
//{{AFX_VIRTUAL(CCaptureDlg) 3Zh)]^
public: lu/
(4ED
virtual BOOL PreTranslateMessage(MSG* pMsg); BJ(M2|VH
protected: OZ;*JR:
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support =2x^nW
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); w4Z'K&