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:
T#YJ5Xw
kc[<5^b5 一、实现方法
5BM rn0 c*V/2"
5 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:
?2S<D5MSb GS,}]c= #pragma data_seg("shareddata")
kybDw{(}gc HHOOK hHook =NULL; //钩子句柄
7!g4 `@!5M UINT nHookCount =0; //挂接的程序数目
Tu=~iQ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
LV]F?O[K= static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
YZc{\~d static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
bl8y
o4 static int KeyCount =0;
TdrRg''@ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
R@[1a+}5 #pragma data_seg()
j'LO'&sQ( u/HNXJ7M`9 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。
e~G um )VkH':yCM 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:
Y-P?t+l g-2(W BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
A~wVY cKey,UCHAR cMask)
10..<v7 {
B"Ttr+ BOOL bAdded=FALSE;
e8hwXz for(int index=0;index<MAX_KEY;index++){
,Y27uey{wa if(hCallWnd[index]==0){
cG4$)q;q hCallWnd[index]=hWnd;
~=c[?: HotKey[index]=cKey;
0t0m?rVW HotKeyMask[index]=cMask;
71k>_'fl bAdded=TRUE;
R?J=5tO KeyCount++;
\`|OAC0a break;
VuA)Ye }
2PEA<{u }
{GQRJ8m return bAdded;
)C#b83 }
hdy
N
//删除热键
Bpdx]5qfK BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
m 3"|$0C~ {
%gV~e@| BOOL bRemoved=FALSE;
ivP#qM1*; for(int index=0;index<MAX_KEY;index++){
q,2 +\i if(hCallWnd[index]==hWnd){
z-;{pPZ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
rL<a^/b/= hCallWnd[index]=NULL;
\WZ]'o6 HotKey[index]=0;
Wt9'-"c HotKeyMask[index]=0;
>jg"y bRemoved=TRUE;
vC%8-;8{H KeyCount--;
0I"r*;9?K break;
uxD$dd? }
o_on/{qz }
P^& =L&U }
iCh,7I,m return bRemoved;
GGkU$qp2~ }
q;=! =aRg 3YJa3fflK b&E9xD/;r DLL中的钩子函数如下:
\"?5CHz* GilmJ2< LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
.{
r
%C4q9 {
+:#UU;W BOOL bProcessed=FALSE;
pn-`QB:{h if(HC_ACTION==nCode)
>}6V=r3[+ {
|Y]4PT#EE if((lParam&0xc0000000)==0xc0000000){// 有键松开
?Y\hC0a60 switch(wParam)
oS Apa {
pF}WMt case VK_MENU:
Z<@dM2b) MaskBits&=~ALTBIT;
}q D0- break;
9a3mN(< case VK_CONTROL:
*_CzCl^
MaskBits&=~CTRLBIT;
s>1Wjz2M break;
6z ,nt case VK_SHIFT:
t p<wMrq< MaskBits&=~SHIFTBIT;
*^Xtorqo break;
Ue2%w/Yo default: //judge the key and send message
_2E* break;
hmM2c15T5 }
u5E\wRn for(int index=0;index<MAX_KEY;index++){
uo[W|Q if(hCallWnd[index]==NULL)
PiZU_~A continue;
}?^5L7n if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
SVJt= M {
rs+
["h SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
}`^DO
Ar bProcessed=TRUE;
X&s"}Hf }
$s"{C"4q }
?3Y~q;I]O }
L wP else if((lParam&0xc000ffff)==1){ //有键按下
w$4*/D}Y switch(wParam)
ZYo?b"6A {
-cP7`.a case VK_MENU:
()o[(Hx+ph MaskBits|=ALTBIT;
pRH'>}rtuH break;
\_l4li case VK_CONTROL:
W|4h;[w MaskBits|=CTRLBIT;
jN T+?2 break;
W\5PsGUsv case VK_SHIFT:
/wT<p MaskBits|=SHIFTBIT;
Qs\*r@6? break;
r2G38/K default: //judge the key and send message
pX?/=T@ Bw break;
%:e.ES }
P87Lo4Rd for(int index=0;index<MAX_KEY;index++){
"< })X.t if(hCallWnd[index]==NULL)
ae0t*;~ continue;
7Xf52\7n if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
&(X 67 {
yV?qX\~* SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
6<mlx' bProcessed=TRUE;
Yaj}_M- }
Nk;ywC"e; }
&>P<Zw- }
3*= _vl3 if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
,)M/mG?, for(int index=0;index<MAX_KEY;index++){
8F9x2CM-[C if(hCallWnd[index]==NULL)
\>[k0< continue;
aUk]wiwIR9 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
y}1Pc* SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
6uIgyO*;k //lParam的意义可看MSDN中WM_KEYDOWN部分
aM+Am,n`@ }
>!Dp'6 }
-G(#,rXk }
,ygUy] return CallNextHookEx( hHook, nCode, wParam, lParam );
'P)c'uqd# }
nh*6`5yj |u]IOw&1 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
L7]o^p{g}Q "x3x$JQZy BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
2N{^V?: BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
P^AI*tH"m 1my1m 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:
-&l%CR,U ow{J;vFy\ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
ohjl*dw {
SY.ZEJcv if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
C8x9 Jrc {
u\;d^A //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
nyetK SaveBmp();
0O[le*3b return FALSE;
05:?5M4}; }
""A6n{4 …… //其它处理及默认处理
/DjsnU~3 }
SlG^ H i+F*vTM2, bh(}f.@
9 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。
EJ(36h 6_:I~TTX 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。
/b\c<'3NY ut#pg+#Q 二、编程步骤
et"Pb_-U n
=WH=:& 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";
UVXSW*$ a?yU;IKJ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
zdw*
?C S'\e"w 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"Qg< 3-&~jm~" 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;
uq;yR[w" N6v?Qzvi 5、 添加代码,编译运行程序。
8+J>jZ }LeS3\+UHl 三、程序代码
Bgn%d4W;G a#k7 aOT0 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
.cHkh^EDY #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
,@/O\fit) #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
8d2\H*a9~ #if _MSC_VER > 1000
]-9w'K d #pragma once
.rITzwgB #endif // _MSC_VER > 1000
([
-i5 #ifndef __AFXWIN_H__
m"'}{3$% #error include 'stdafx.h' before including this file for PCH
$8xb|S[ #endif
9K#3JyW* #include "resource.h" // main symbols
-7]j[{?w class CHookApp : public CWinApp
]<C]`W2{ {
#UhH public:
1;H"4u_IG& CHookApp();
L~^5Ez6U // Overrides
xQ7U$QF|] // ClassWizard generated virtual function overrides
r~2hTie //{{AFX_VIRTUAL(CHookApp)
BjagG/sX public:
k|\M(Z*(P virtual BOOL InitInstance();
vzFpXdt virtual int ExitInstance();
]ly" K!1, //}}AFX_VIRTUAL
pu+Q3NfR //{{AFX_MSG(CHookApp)
f*B-aj# // NOTE - the ClassWizard will add and remove member functions here.
w]yVNB // DO NOT EDIT what you see in these blocks of generated code !
R^$|D)( //}}AFX_MSG
8I *N DECLARE_MESSAGE_MAP()
'5 ~cd };
D%nd7
| LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
W>i"p~! BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
FOk;=+ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
* 70ZAo4 BOOL InitHotkey();
Z#L4n#TT BOOL UnInit();
q:TNf\/o #endif
1kKfFpN pITF%J@_] //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Hj|&P/jY]* #include "stdafx.h"
*dw.Ug #include "hook.h"
<y] 67:"<v #include <windowsx.h>
kI)}7e #ifdef _DEBUG
uT4|43<
G #define new DEBUG_NEW
`vgaX,F* #undef THIS_FILE
%ACW"2#( static char THIS_FILE[] = __FILE__;
Bskp&NV': #endif
- ~|Gwr" #define MAX_KEY 100
h7!O
K #define CTRLBIT 0x04
w+R7NFq #define ALTBIT 0x02
*k}m?;esb #define SHIFTBIT 0x01
Q`<{cFsU #pragma data_seg("shareddata")
j*G: 8Lg HHOOK hHook =NULL;
DJL.P6 -W UINT nHookCount =0;
qrYbc~jI7 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
$vf gYl4q static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
HDhISPg static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
{9U!0h-2" static int KeyCount =0;
c\1X NPGG static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
#mw!_]
#pragma data_seg()
p@su:B2Rl HINSTANCE hins;
> 0MP[ void VerifyWindow();
*G>
x07S)~ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
\X:e9~ //{{AFX_MSG_MAP(CHookApp)
p35=CX`T. // NOTE - the ClassWizard will add and remove mapping macros here.
**Ioy+ // DO NOT EDIT what you see in these blocks of generated code!
],pB:= //}}AFX_MSG_MAP
vTO9XHc E END_MESSAGE_MAP()
8m?(* [[ 3!{imQT CHookApp::CHookApp()
FnA Kfh( {
$u!(F]^ // TODO: add construction code here,
d#rr7O // Place all significant initialization in InitInstance
E]OexRJ^i }
T,pr&1]Lw h#hr'3bI1 CHookApp theApp;
Nh.+woFq4 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
^?`fN'!p {
O8@65URKx BOOL bProcessed=FALSE;
$72eHdy/yl if(HC_ACTION==nCode)
J[ Gpd {
l#KcmOz if((lParam&0xc0000000)==0xc0000000){// Key up
5wx_ol}2 switch(wParam)
x|0C0a\"A {
_-_iw&F case VK_MENU:
sN[}B{+ MaskBits&=~ALTBIT;
D$}8GYq break;
SsZC g#i case VK_CONTROL:
xpR`fq MaskBits&=~CTRLBIT;
ttsR`R1.k break;
Z!"-LQJ case VK_SHIFT:
6dIPgie3w MaskBits&=~SHIFTBIT;
*-nO,K>y` break;
5^g* default: //judge the key and send message
gZ,h95' break;
9p W~Gz }
F/s
n"2 for(int index=0;index<MAX_KEY;index++){
H0af u)$, if(hCallWnd[index]==NULL)
YhN<vZ}U!~ continue;
N#T'}>t y if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
O
k`}\NZL {
s:3[#&PQpN SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
M&V'*.xz bProcessed=TRUE;
|(>`qL{| }
9eMle?pF }
<L-F3Buu }
#rkq
?:Q else if((lParam&0xc000ffff)==1){ //Key down
/+Z*)q+SbT switch(wParam)
%bi ie {
QHR,p/p case VK_MENU:
~Gu$EqQ MaskBits|=ALTBIT;
d?fS#Ryb break;
1rm\ u% case VK_CONTROL:
>C|pY6 MaskBits|=CTRLBIT;
f% pT-# break;
6.D|\;9{c case VK_SHIFT:
Jl{ 0q7b MaskBits|=SHIFTBIT;
_Si=Jp][ break;
S^rf^% default: //judge the key and send message
dCd~]CI break;
`B)@ }
*S,~zOYN for(int index=0;index<MAX_KEY;index++)
I1<WHq
{
=^4Z]d if(hCallWnd[index]==NULL)
<s9{o
uZ continue;
ZNQx;51 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
z?o8h
N\ {
gNCS*a SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
l f>/ bProcessed=TRUE;
xo[o^go }
b84l`J }
T8^9*]:@c! }
[^qT?se{ if(!bProcessed){
&hYgu3O for(int index=0;index<MAX_KEY;index++){
NM3;l}Y8 if(hCallWnd[index]==NULL)
M"3"6U/ e continue;
_**Nlp*% if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
j,0`k SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
'UlVc2%{ }
|}=eY?iXo }
KQ\K:# }
=CLPz8 return CallNextHookEx( hHook, nCode, wParam, lParam );
6
5govor }
n5}]C{s' _ ;HdX$op BOOL InitHotkey()
p@tg pFt {
=5|7S&{ if(hHook!=NULL){
5$9$R(KU nHookCount++;
~i.*fL_Y return TRUE;
NqD]p{>Y }
@](vFb else
c-+NWC hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
Btm,'kBG if(hHook!=NULL)
_p )NZ7yC nHookCount++;
2) X#&IE return (hHook!=NULL);
~q`!928Gu }
(y9KO56.V& BOOL UnInit()
2 @#yQB1 {
(`.# n3{ if(nHookCount>1){
S=qh7ML nHookCount--;
@A,8>0+ return TRUE;
DDrR9}k }
'@{:FrG*U BOOL unhooked = UnhookWindowsHookEx(hHook);
qb"S if(unhooked==TRUE){
/oPW0of nHookCount=0;
#UM,)bH hHook=NULL;
5 ^{~xOM5 }
t'44X return unhooked;
NW\CEJV }
%-n)L Nv5^2^Sc= BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Y|tHU'x {
dseI~} BOOL bAdded=FALSE;
'va[)~! for(int index=0;index<MAX_KEY;index++){
nb_/1{F if(hCallWnd[index]==0){
^Om}9rXw1 hCallWnd[index]=hWnd;
/2K"Mpf8 HotKey[index]=cKey;
x1gS^9MqCB HotKeyMask[index]=cMask;
bDl:,7; bAdded=TRUE;
+#IUn KeyCount++;
;$D,w break;
opa/+V3E4 }
|
Y:`>2ev }
YmljHQP return bAdded;
"VaWZ* }
YIe1AF}
j^jC| BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
8qe[x\,"8 {
hW*o;o7u BOOL bRemoved=FALSE;
0,hs%x>v for(int index=0;index<MAX_KEY;index++){
P'~`2W0sz if(hCallWnd[index]==hWnd){
971=OEyq* if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
6))":<J hCallWnd[index]=NULL;
*BKD5EwS HotKey[index]=0;
,6+joKe- HotKeyMask[index]=0;
ai 4 k? bRemoved=TRUE;
BK!Yl\I< KeyCount--;
HlE8AbEg break;
>LPb>t5%p }
e'mF1al }
zg jg #| }
eU"yF >6' return bRemoved;
H;`F}qQ3 }
gJ l^K INndTF void VerifyWindow()
19fa7E< {
[Qs`@u<% for(int i=0;i<MAX_KEY;i++){
qGX@mo({ if(hCallWnd
!=NULL){ Jt$YSp=!!
if(!IsWindow(hCallWnd)){ Le#srr
hCallWnd=NULL; "dpjxH=xO
HotKey=0; x}2nn)fdZ
HotKeyMask=0; t|@5,J
KeyCount--; cyNE}
} CVO_F=;
} %;&lVIU0
} \]>821r
} ]]p\1G
K+Him]
b
BOOL CHookApp::InitInstance() +"84.PZ
{ A^aY-V
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 7 2$S'O%,0
hins=AfxGetInstanceHandle(); ";.j[p:gi
InitHotkey(); "'5(UiSFz
return CWinApp::InitInstance(); ")8l'^Mq2
} ^mC~<pP(
9swHa
int CHookApp::ExitInstance() 2wpJ)t*PF
{ P 0\`4Cr!
VerifyWindow(); 3nBZ+n4z
UnInit(); La6
9or
return CWinApp::ExitInstance(); !WXV1S
} aH;AGbp
.7.1JT#@A7
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file A^}#
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) |}{gE=]
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ pbKmFweq
#if _MSC_VER > 1000 aUL7]'q}
#pragma once 09McUR@
#endif // _MSC_VER > 1000 =b66H]h?
uWx<J3~q.
class CCaptureDlg : public CDialog r?)1)?JnHe
{ 4!14:mq
// Construction l|+$4 Nb2
public: 2lfEJw($
BOOL bTray; g]j&F65D
BOOL bRegistered; 6}Y==GPt
BOOL RegisterHotkey(); 8$c) ]Bv
UCHAR cKey; ~> )>hy)
UCHAR cMask; ok6t|
7sq
void DeleteIcon(); In4VS:dD
void AddIcon(); BoT#b^l
UINT nCount; }alq~jY
void SaveBmp(); yVVyWte,
CCaptureDlg(CWnd* pParent = NULL); // standard constructor p+Q 9?9
// Dialog Data S.[L?uE~F
//{{AFX_DATA(CCaptureDlg) WS6Qp`c)e
enum { IDD = IDD_CAPTURE_DIALOG }; ;a|%W4 "
CComboBox m_Key; qbQdxKk
BOOL m_bControl; ~_0XG0oA
BOOL m_bAlt; BZv:E?1z
BOOL m_bShift; kJ%a;p`O
CString m_Path; V.8Vy1 $
CString m_Number; !pj&