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:
{26ONa#i
N?.%?0l 一、实现方法
8,uB8C9 A=
w9V 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:
Si~vDQ7" ~ar=PmYV7 #pragma data_seg("shareddata")
:<|<|qJWo HHOOK hHook =NULL; //钩子句柄
`He,p - UINT nHookCount =0; //挂接的程序数目
1x,tu}<u^ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
+sJrllrE( static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
zen*PeIrA^ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
+U@<\kIF static int KeyCount =0;
ZzX~&95G static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
n?c]M #pragma data_seg()
twx[s$O'b &
GreN 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
@/1w4'M h?pkE DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
D:K4H+ch ()H:Uv M=t BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
Km^&<3ch# cKey,UCHAR cMask)
+}a ]GTBgA {
{*ob_oc BOOL bAdded=FALSE;
znHnVYll( for(int index=0;index<MAX_KEY;index++){
Y5j]Z^^v if(hCallWnd[index]==0){
xL" |)A = hCallWnd[index]=hWnd;
s8h-,@p HotKey[index]=cKey;
l(Q?rwI8Y HotKeyMask[index]=cMask;
|ely|U. Tf bAdded=TRUE;
vEn4L0D KeyCount++;
M4W5f#C5Ee break;
jkvgoxY }
)[Yv?>ib }
2r ZxSg return bAdded;
=ha{Ziryo }
&:7ZQ1 //删除热键
+j4"!:N}B BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
'f?$"U JF {
{ .?/) BOOL bRemoved=FALSE;
SZXY/~=h for(int index=0;index<MAX_KEY;index++){
\oZ5JoO if(hCallWnd[index]==hWnd){
NrJKbk^4u/ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
nt@aYXK4| hCallWnd[index]=NULL;
T|TO }_x HotKey[index]=0;
S)/_muP HotKeyMask[index]=0;
to$h2#i_ bRemoved=TRUE;
G}G#i`6o KeyCount--;
j.@\3' break;
U,.![TP }
z+>}RT] }
WH\))y- }
::/j$bL return bRemoved;
9U%N@Dq`Z }
E^SH\5B zO
MA 9*(aUz9j DLL中的钩子函数如下:
jXMyPNTK xagBORg+Bd LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
>HS W]"k {
Zp#v Hs BOOL bProcessed=FALSE;
X'"SVO. if(HC_ACTION==nCode)
pLzk {
PKzyV ; if((lParam&0xc0000000)==0xc0000000){// 有键松开
j+
LawW- switch(wParam)
J`^I./ {
oo.2Dn6z case VK_MENU:
9\DQ>V TQ MaskBits&=~ALTBIT;
`9b7>Nn< break;
0p\@!Z H case VK_CONTROL:
D= h)& MaskBits&=~CTRLBIT;
,kn">k9 break;
'u1?tQ=gmk case VK_SHIFT:
6efnxxY}sa MaskBits&=~SHIFTBIT;
X7g1:L1Ys break;
G"XVn~] default: //judge the key and send message
VH1d$ break;
=>! Y{:
y( }
'^"6+ k for(int index=0;index<MAX_KEY;index++){
X.e7A/ClEo if(hCallWnd[index]==NULL)
5>\/[I/! continue;
[E
] E if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
c*@E_}C# {
g'm+/pU)w) SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
1OF&
* bProcessed=TRUE;
E3iW-B8u8 }
:B:"NyPA }
6 M*O{f }
hHMN6i else if((lParam&0xc000ffff)==1){ //有键按下
byfJy^8G switch(wParam)
?28N ^ {
r|qp3x case VK_MENU:
*^wm1|5 MaskBits|=ALTBIT;
IDG}ZlG break;
\9g+^vQg case VK_CONTROL:
*NCl fkZ MaskBits|=CTRLBIT;
9& 83n(m break;
GJqJlgHe case VK_SHIFT:
lh;:M-b9 MaskBits|=SHIFTBIT;
gjAIEI break;
ixT:)|'i default: //judge the key and send message
E L9]QI break;
B,=H@[Fj }
/x1![$oC0 for(int index=0;index<MAX_KEY;index++){
={xE!" if(hCallWnd[index]==NULL)
7!JQB continue;
Yn G_m] if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
2mGaD\?K {
[a
wjio SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
fu]s/'8B bProcessed=TRUE;
LMAE)]N }
k>g_Z`%< }
!GNBDRr }
EG=Sl~~o if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
]@Uq=?% for(int index=0;index<MAX_KEY;index++){
|VNnOM if(hCallWnd[index]==NULL)
nPy$D-L, continue;
~S7D>D3S if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
aiu5}%U SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
@0u~?!g@ //lParam的意义可看MSDN中WM_KEYDOWN部分
l|k`YC x }
z\%Ls
}
F
70R1OYU }
fV'ZsJ N return CallNextHookEx( hHook, nCode, wParam, lParam );
$H9%J }
J:zU,IIJ Q{5kxw1ZF 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
3skC$mpJHw 20nP/e BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
<
RH UH)I BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
4s*ZS}]
o u;/ Vyu 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:
{*I``T_+ xe`
</ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
l.NEkAYPmH {
F6{bjv2A if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
/Id%_,}Kb {
[.uG5%fa //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
*=I}Qh(1 SaveBmp();
#/<&*Pu5t return FALSE;
?I~()]k5 }
<y NM%P<Oy …… //其它处理及默认处理
V13N}] }
`6]%P(#a 5MtLT#C3r n' q4 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。
S9~+c GfmI<{da 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。
ei[j1F /*X2c6<d 二、编程步骤
zM(vr"U =aBctd:eX` 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";
~3WF,mW V^Q#:@0 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
yU-e3O7L UZJCvfi 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;
.xm.DRk3 vRHd&0 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;
xk5@d6Y{r HV{wI1 5、 添加代码,编译运行程序。
h1B16) vPTM 三、程序代码
w.YiO5|y #x 177I\ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
ASk|A! #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
nwF2aRNV #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
@c;|G$E@3 #if _MSC_VER > 1000
J:V6 #pragma once
5',8 ziJQ #endif // _MSC_VER > 1000
)W;o<:x3 #ifndef __AFXWIN_H__
4;0lvDD #error include 'stdafx.h' before including this file for PCH
5n9B?T8C #endif
P'Ux%Q+B> #include "resource.h" // main symbols
Hn%xDJ' class CHookApp : public CWinApp
(2^gVz=j {
2[O&NdP\Zk public:
/2=#t-p+ CHookApp();
GycSwQ
, // Overrides
0+kH:dP{ // ClassWizard generated virtual function overrides
{ +
Zd*)M[ //{{AFX_VIRTUAL(CHookApp)
Pa
V@aM~3 public:
`\#B18eU virtual BOOL InitInstance();
`OXpU,Z 6U virtual int ExitInstance();
B1>/5hV} //}}AFX_VIRTUAL
8TLgNQP //{{AFX_MSG(CHookApp)
&h^9}>rVjV // NOTE - the ClassWizard will add and remove member functions here.
4'a=pnE$
// DO NOT EDIT what you see in these blocks of generated code !
p8h9Ng*&` //}}AFX_MSG
;;C?{ DECLARE_MESSAGE_MAP()
d9;g]uj` };
_lGdUt 2 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
o:3dfO%nuM BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
iB%gPoDCL@ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
w~"KA6^ BOOL InitHotkey();
Kgi<UkFP BOOL UnInit();
X[&Wkr8x ' #endif
ymx>i~>7J ZaV8qAsP //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
['B?i1 . #include "stdafx.h"
UBaAx21x #include "hook.h"
0 yuW*z #include <windowsx.h>
<b`E_ #ifdef _DEBUG
rA5=dJ"I #define new DEBUG_NEW
x7jC)M<k0 #undef THIS_FILE
X.f>'0i static char THIS_FILE[] = __FILE__;
O&4SCVZp #endif
AP7Yuv` #define MAX_KEY 100
]+XYEv #define CTRLBIT 0x04
xp}hev^@$ #define ALTBIT 0x02
2(u,SQ #define SHIFTBIT 0x01
G IT>L #pragma data_seg("shareddata")
tG9BfGF HHOOK hHook =NULL;
<UV1!2nv* UINT nHookCount =0;
E[@ u
3i8 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
$RIecv<e_ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
t\{'F7 static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
&]v4@%<J static int KeyCount =0;
vY${;#~| static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
R`DKu= #pragma data_seg()
Nn~~!q HINSTANCE hins;
u'|4?"uz void VerifyWindow();
||hb~%JK6 BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
PT=2@kH //{{AFX_MSG_MAP(CHookApp)
gcPTLh[^Er // NOTE - the ClassWizard will add and remove mapping macros here.
TarIPp // DO NOT EDIT what you see in these blocks of generated code!
,9}h //}}AFX_MSG_MAP
ES.fOdx END_MESSAGE_MAP()
aI6$? wus h]5C|M| CHookApp::CHookApp()
JORGj0v {
aB{vFTD5 // TODO: add construction code here,
)z73-M V" // Place all significant initialization in InitInstance
q Gw -tPD< }
gX]-\ njScz"L~ CHookApp theApp;
+e yc`J LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
s:/8[(A {
0=* 8
BOOL bProcessed=FALSE;
Ma.`A if(HC_ACTION==nCode)
[E!oQVY {
aE&,]'6 if((lParam&0xc0000000)==0xc0000000){// Key up
m#PY,y switch(wParam)
Y^8C)p9r {
K?B{rE Lp case VK_MENU:
e;Ti&o} MaskBits&=~ALTBIT;
!`g~F\l break;
hyCh9YOu) case VK_CONTROL:
]h* c,. MaskBits&=~CTRLBIT;
]>LhkA@V break;
Z&1T case VK_SHIFT:
\W1,F6&j MaskBits&=~SHIFTBIT;
R7$:@<:g break;
9[b<5Llt default: //judge the key and send message
Q[vJqkgT break;
wRcAX%n& }
CFzNwgv]z for(int index=0;index<MAX_KEY;index++){
Rzbj if(hCallWnd[index]==NULL)
WQ[_hg|k continue;
"?ucO4d if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
!;i`PPRwk {
Ox&P}P0f SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
8+a4>8[M bProcessed=TRUE;
s \;" X }
\`oT#|0 }
q|o}+Vr }
DoJ\ q+ else if((lParam&0xc000ffff)==1){ //Key down
J&[@}$N switch(wParam)
,0*&OXt {
t2F_uCr case VK_MENU:
k2c}3 MeP MaskBits|=ALTBIT;
6x h:/j3 break;
xy5lE+E_U case VK_CONTROL:
,&jhlZ i MaskBits|=CTRLBIT;
J
pFfzb
break;
96 q_K84K case VK_SHIFT:
0E,8R{e MaskBits|=SHIFTBIT;
0fF(Z0R, break;
Pz>s6 [ob default: //judge the key and send message
!c}O5TI|# break;
hd>aZ"nm1 }
_/uFsYC for(int index=0;index<MAX_KEY;index++)
K/tRe/t} {
6-yd](" if(hCallWnd[index]==NULL)
"U!AlZ`g continue;
WG N=Y~E if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
d
F9!G;V {
Cdas P9"1 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
P<l&0dPO8 bProcessed=TRUE;
t]y
D-3'l& }
TD1 [ }
i5Zk_-\#H }
C~nzH,5 if(!bProcessed){
^B(V4-| for(int index=0;index<MAX_KEY;index++){
Bt>}rYz1 if(hCallWnd[index]==NULL)
LJk@Vy <? continue;
WM| dKF
if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
|uqf:V`z: SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
#w,Dwy }
7ePqmB<. }
0vEoGgY0*: }
vy0X_DPCr return CallNextHookEx( hHook, nCode, wParam, lParam );
l)Pu2!Ic }
1<BX]-/tP &<wuJ%'>)Z BOOL InitHotkey()
QW$G {
;3d"wW]}7K if(hHook!=NULL){
FME3sa$ nHookCount++;
>TOu|r return TRUE;
+W:=e,= }
{Or; else
%MrWeYd1 hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
0'V5/W if(hHook!=NULL)
_d"b;4l nHookCount++;
^HV>`Pjd}= return (hHook!=NULL);
(eCJ;%%k }
}`W){]{kO BOOL UnInit()
J6U$qi {
\R|4( +]x if(nHookCount>1){
HG+%HUO$ nHookCount--;
::ajlRZG return TRUE;
"OQ^U_ }
plb!.g BOOL unhooked = UnhookWindowsHookEx(hHook);
rM .|1(u if(unhooked==TRUE){
u=/{cOJI6 nHookCount=0;
Y%PwktQm hHook=NULL;
~aMlr6; }
A*2
bA return unhooked;
^cczJOxB }
^aH\7J@Y 5jd,{< BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
4a'N>eDR {
r<K(jG[:{f BOOL bAdded=FALSE;
GliwY_ for(int index=0;index<MAX_KEY;index++){
k.uMp<)D if(hCallWnd[index]==0){
zaah^.MA| hCallWnd[index]=hWnd;
MYla OT HotKey[index]=cKey;
^Wc@oa` HotKeyMask[index]=cMask;
7on.4/;M bAdded=TRUE;
?Cl%{2omO KeyCount++;
|K.mP4CKY break;
Qa.<K{m#? }
^C_#<m_k }
o
Z%9_$Z return bAdded;
a^`rtvT }
3):A N F+iza;DP BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
y^%n'h{ {
?YZ- P{rTS BOOL bRemoved=FALSE;
=at@ Vp/y for(int index=0;index<MAX_KEY;index++){
vg3=8># if(hCallWnd[index]==hWnd){
_9=Yvc= if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
=bHD#o|R hCallWnd[index]=NULL;
LL2=& VK HotKey[index]=0;
8g&?
Cc HotKeyMask[index]=0;
kKAP"'v bRemoved=TRUE;
.Nw=[ KeyCount--;
W7U2MqQ break;
#=6E\&NC }
W}5xmz }
kL$!E9 }
B?4boF?~ return bRemoved;
xL{a }
QlJ)F{R8il ~NQ72wph{ void VerifyWindow()
)xbHCoU, {
MrDc$p W G for(int i=0;i<MAX_KEY;i++){
%kdEun if(hCallWnd
!=NULL){ $Hj.{;eC/k
if(!IsWindow(hCallWnd)){ }HY-uQ%@g
hCallWnd=NULL; w+yC)Rmz
HotKey=0; F )W:
HotKeyMask=0; !{^PO<9
KeyCount--; S4G^z}{_
} *QLI3B9V
} b*`lk2oMa/
} ZaL.!g
} 7cTV?nc
t0IEaj75c
BOOL CHookApp::InitInstance() <-[wd.M_
{ pov)Z):}G<
AFX_MANAGE_STATE(AfxGetStaticModuleState()); gLy&esJl1
hins=AfxGetInstanceHandle(); m06ALD_
InitHotkey(); {buo^kgj`]
return CWinApp::InitInstance(); :.$3vaZ@
} }[4r4 1[
~g5[$r-u-u
int CHookApp::ExitInstance() 6"~P/\jP
{ F;+|sMrq
VerifyWindow(); @ Wd9I;hWv
UnInit(); ~},=OF-b
return CWinApp::ExitInstance();
k~jP'aD
} EL(nDv
1IZ3=6
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file MBqt&_?K
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) JwAYG5W
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ f}x.jxY?
#if _MSC_VER > 1000 H^s<{E0<
#pragma once qYlhlHD
#endif // _MSC_VER > 1000 T~Gvp0r}h
U-R6xxPZ
class CCaptureDlg : public CDialog `QyO`y=?[Y
{ {&\jW!&n
// Construction =5kY6%E7c
public: Mz~M3$$9n
BOOL bTray; OoA|8!CFa
BOOL bRegistered; aFS,GiB
BOOL RegisterHotkey(); Q$="_y2cTA
UCHAR cKey; hM{{\yZS
UCHAR cMask; Uc@Ao:
void DeleteIcon(); 4`!Z$kt
void AddIcon(); Jo@|"cE=
UINT nCount; no<
^f]33
void SaveBmp(); HbXPok
CCaptureDlg(CWnd* pParent = NULL); // standard constructor |Z=^`J
// Dialog Data qI~xlW
//{{AFX_DATA(CCaptureDlg) Tl2C^j
enum { IDD = IDD_CAPTURE_DIALOG }; @wE5S6! B\
CComboBox m_Key; (X?%^^e!
BOOL m_bControl; 4}4Pyjh
BOOL m_bAlt; A29gz:F(
BOOL m_bShift; |j#C|V%kV
CString m_Path; 1 D<_N
CString m_Number; my4giC2a
//}}AFX_DATA _OuWB"
// ClassWizard generated virtual function overrides Kfh|
//{{AFX_VIRTUAL(CCaptureDlg) (2:/8\_P
public: UN]f"k&