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:
R{Z-m2La
|iYg > 一、实现方法
zSTR^sgJ +ZsX*/TOn 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:
-XK0KYhgW F4#g?R::U #pragma data_seg("shareddata")
YB))S!;Ok HHOOK hHook =NULL; //钩子句柄
x+5p1sv6 UINT nHookCount =0; //挂接的程序数目
o?Nu:&yE static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
+Lm4kA+aE5 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
lU]un&[N static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
rsNf$v-* static int KeyCount =0;
J:dof:q static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
or*HC&c7 #pragma data_seg()
=v~1qWX %u\26[/ 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
_ o6G6e, &-l8n^ DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
NLd``=& }-p[V$:S BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
gT+Bhr cKey,UCHAR cMask)
GOy%^:Xd {
1MsWnSvzf BOOL bAdded=FALSE;
'!h/B;*( for(int index=0;index<MAX_KEY;index++){
4Cb9%Q0 if(hCallWnd[index]==0){
u^W2UE\ hCallWnd[index]=hWnd;
_, AzJ^ HotKey[index]=cKey;
v5ur&egVs HotKeyMask[index]=cMask;
[]W;t\h bAdded=TRUE;
5AeQQU KeyCount++;
oP?YA-#nc break;
OKOu`Hz@ }
yoe}$f4 }
imL_lw^? return bAdded;
b;mSQ4+ }
mg:!4O$K //删除热键
iTo k[uJ} BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
`s#Hq\C {
m`?MV\^ BOOL bRemoved=FALSE;
A1Y7;-D for(int index=0;index<MAX_KEY;index++){
<G8w[hs if(hCallWnd[index]==hWnd){
%GEJnJ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
&NZfJs hCallWnd[index]=NULL;
t/o N>mQG HotKey[index]=0;
"VxWj}+] HotKeyMask[index]=0;
,{eUP0] bRemoved=TRUE;
h&@R| N KeyCount--;
4 {GU6v)f break;
4\5uY }
QrG`&QN }
gIEl. }
U!5)5c}G return bRemoved;
neF]=uCWnT }
bF}V4"d,B3 `<" m%> 9Mm!%Hu DLL中的钩子函数如下:
T5Eseesp iX{G]< n LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
1t[j"CG(o {
:VmHfOO BOOL bProcessed=FALSE;
KGHq rc if(HC_ACTION==nCode)
`em9T oJV {
SF]@| if((lParam&0xc0000000)==0xc0000000){// 有键松开
FE7)E.U switch(wParam)
rEZ8eeB[3 {
hv$yV%.` case VK_MENU:
m#H3:-h, MaskBits&=~ALTBIT;
4A`NJ break;
-|yb[~3 case VK_CONTROL:
#!J(4tXny MaskBits&=~CTRLBIT;
^cvl:HOog break;
'fwU]Hm case VK_SHIFT:
&sVvWNO#2 MaskBits&=~SHIFTBIT;
VzS&`d.h break;
@gGRm default: //judge the key and send message
6~meM@ break;
'WyTI^K9 }
?wpB` for(int index=0;index<MAX_KEY;index++){
^,Ydr~|T if(hCallWnd[index]==NULL)
<oMUQ*OtV continue;
({}( qm if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
ewsKH\#
{
]LPQYL SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
cFd
>oDS bProcessed=TRUE;
X*oMFQgP }
*DI)? }
v`q\6i[- }
2i#Sn' 1 else if((lParam&0xc000ffff)==1){ //有键按下
(kBP(2V switch(wParam)
p^m5`{1]x {
0Sl]!PZR1 case VK_MENU:
72T I MaskBits|=ALTBIT;
uUR~&8ERX break;
J<n+\F-s case VK_CONTROL:
z+2V4s = MaskBits|=CTRLBIT;
wgeNs9L break;
Zc&&[g case VK_SHIFT:
>:sUL<p MaskBits|=SHIFTBIT;
tS# `.F~y break;
t6N*6ld2b default: //judge the key and send message
~89P[$6 break;
5__+_hO
;3 }
X+8B!F for(int index=0;index<MAX_KEY;index++){
|tMn={ if(hCallWnd[index]==NULL)
XdEPbD- continue;
Vsq8H}K if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
A^fjfa);V {
=V+I=rqo SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
<g8K})P bProcessed=TRUE;
-7>)i }
("7M
b{ }
*mG`_9 }
/Poet%XvRx if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
(3vHY`9 for(int index=0;index<MAX_KEY;index++){
&7?R+ZGo if(hCallWnd[index]==NULL)
(n(
fI f continue;
z;u>
Yz+3 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
0CvsvUN@ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
t/i5,le //lParam的意义可看MSDN中WM_KEYDOWN部分
C2e.2)y }
F-Z%6O,2 }
UnWW/]E }
a.F Al@Br return CallNextHookEx( hHook, nCode, wParam, lParam );
W\*-xf|"d }
sE(HZR1 8Ad606 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:
A!W0S d?idTcgs BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
"GT4s?6O BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
@!=\R^#p {kI#A?M 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:
{Ng oYl )+I.|5g LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
ZBD;a;wx {
vP!GJX&n5 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
iSK+GQ~ {
]pA(K?Lbg //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
:
DG)g3# SaveBmp();
H( -Y return FALSE;
rk2xKm^w }
}|)R
…… //其它处理及默认处理
2 mjV~ }
AS!6XT 5,"l0nrk 3{Nbp 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。
%rQuBi# 1f `\>.h 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。
Lr;(xw\[' z~6y+ 二、编程步骤
z1OFcqm UQCo}vM 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";
k?nQ?B
W < O*6T%; 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
;d.K_P Q }k.JS~# 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;
C=Fzu&N} |C \}P 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;
4fV3Ear=j KP;(Q+qTx 5、 添加代码,编译运行程序。
Huw\&E }'"Gr%jf( 三、程序代码
PrQ?PvA<L vEM(bT=H ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
[a[/_Sf{ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
D:\ g,\Z #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
/h2b;" #if _MSC_VER > 1000
%3;Fgk y #pragma once
!4"sX+z9 #endif // _MSC_VER > 1000
fpyz' #ifndef __AFXWIN_H__
]36sZ
* #error include 'stdafx.h' before including this file for PCH
qr\!*\9 #endif
t,)N('m}= #include "resource.h" // main symbols
bZ_mYyBh class CHookApp : public CWinApp
>M!xiQX {
_GQz!YA public:
jo+w> CHookApp();
gxPx&Z6jF // Overrides
O^>jdl!TZ // ClassWizard generated virtual function overrides
_:n b&B //{{AFX_VIRTUAL(CHookApp)
3CjL\pIC public:
FUK3)lT virtual BOOL InitInstance();
WnFG{S{s virtual int ExitInstance();
!33#. @[ //}}AFX_VIRTUAL
jdeV|H} u //{{AFX_MSG(CHookApp)
S/vf'gj // NOTE - the ClassWizard will add and remove member functions here.
_;A $C( // DO NOT EDIT what you see in these blocks of generated code !
~Aad9yyi //}}AFX_MSG
9&%fq)gS DECLARE_MESSAGE_MAP()
6!iJ;1PeE };
/T^ JS LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
F,Xo|jjj BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
Hk_y/97OO BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
v}G]X Z8 BOOL InitHotkey();
nq}Q BOOL UnInit();
`7aDEzmJ #endif
!;@_VWR 38V3o`f //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
7DW]JK l #include "stdafx.h"
`;,Pb&W~ #include "hook.h"
p_*M:P1Ma4 #include <windowsx.h>
~d{.ng 4K #ifdef _DEBUG
m^%|ZTrwN7 #define new DEBUG_NEW
?i\B^uB #undef THIS_FILE
M/PFPJ >` static char THIS_FILE[] = __FILE__;
9n]|PEoAB #endif
p5=|Y^g ! #define MAX_KEY 100
+YOKA* #define CTRLBIT 0x04
qJ!Z~-hS #define ALTBIT 0x02
39U5jj7i #define SHIFTBIT 0x01
\ A1uhHP! #pragma data_seg("shareddata")
fHrt+_Zn| HHOOK hHook =NULL;
6}~pq1IF{ UINT nHookCount =0;
>e5 *prx+ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
!U_K&f static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
-
N>MBn static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
$$i.O} static int KeyCount =0;
.o%^'m"=D[ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
7x]4`#u #pragma data_seg()
Sydh2d HINSTANCE hins;
,7Y-k'7Kop void VerifyWindow();
@4~=CV%j BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
Dq\ Jz~ //{{AFX_MSG_MAP(CHookApp)
V{-AP=C7 // NOTE - the ClassWizard will add and remove mapping macros here.
|XYEn7^r // DO NOT EDIT what you see in these blocks of generated code!
eC
DIwB28 //}}AFX_MSG_MAP
8GPIZh'0h END_MESSAGE_MAP()
\2[<XG(^ TG48%L CHookApp::CHookApp()
m4K* < {
"\"DCDKmG // TODO: add construction code here,
js^ ,(CS // Place all significant initialization in InitInstance
~Vh(6q.oT }
.Hhh i pN6%&@) = CHookApp theApp;
W^,S6! LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
}*]B-\> {
v1U?&C BOOL bProcessed=FALSE;
.%EL \2 if(HC_ACTION==nCode)
Rx07trfN {
=*BIB5 if((lParam&0xc0000000)==0xc0000000){// Key up
%Kh4m7 switch(wParam)
8rZ!ia! {
CF!Sa 6 case VK_MENU:
MmPU7Nl%X MaskBits&=~ALTBIT;
_3iHkQr break;
#H [Bb2(j case VK_CONTROL:
72W,FU~OD MaskBits&=~CTRLBIT;
I7+9~5p break;
~8 H_u case VK_SHIFT:
+1JH MaskBits&=~SHIFTBIT;
p1pQU={< break;
u*S=[dq default: //judge the key and send message
r'LVa6e"N break;
'[|+aJ }
zr v] for(int index=0;index<MAX_KEY;index++){
ql{(Lf$ if(hCallWnd[index]==NULL)
Jo(`zuLJ continue;
0X8t>#uF if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
>DM44 {
V~DMtB7 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Xm2\0=v5; bProcessed=TRUE;
8VG!TpX/B }
-W{DxN1 }
&K_)#v`| }
Tl]e%A`| else if((lParam&0xc000ffff)==1){ //Key down
$yDWu"R8 switch(wParam)
vgt]:$ {
m ~#! case VK_MENU:
NvE}eA# MaskBits|=ALTBIT;
UEs7''6RM break;
%t=kdc0=_ case VK_CONTROL:
~fl@ 2 MaskBits|=CTRLBIT;
sKz`aqI break;
@[<nQZw: case VK_SHIFT:
MfO:m[s MaskBits|=SHIFTBIT;
7`vEe'qz break;
O-]mebTvw default: //judge the key and send message
qs\2Z@; break;
9Gy }
+:=(#Y for(int index=0;index<MAX_KEY;index++)
:Eh\NOc_O {
onCKI," if(hCallWnd[index]==NULL)
[AH6~-\ x continue;
( m\$hX if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
v$~QCtc {
L$'[5"ma
; SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Tm^89I]L bProcessed=TRUE;
y4Z&@,_{ }
$CTSnlPq }
*b *G2f^ }
682Z}"I0 if(!bProcessed){
eg<bi@C1| for(int index=0;index<MAX_KEY;index++){
# ,uya2!) if(hCallWnd[index]==NULL)
%98' @$:0 continue;
&wd;EGGT!q if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
"q}FPJ^l_N SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
bawJ$_O_ }
"xcX'F^ }
N#V.1<Y }
m^' uipa\ return CallNextHookEx( hHook, nCode, wParam, lParam );
lN,/3\B }
H|ozDA rrg96WD BOOL InitHotkey()
$p!yhn7 {
}7fZ[J3 if(hHook!=NULL){
^
PI 5L nHookCount++;
~vLW.: return TRUE;
gM>t0)mGK }
L!/\8-&$P else
4${jr\q] hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
~DO4, if(hHook!=NULL)
tMj;s^P1 nHookCount++;
s,bERN7'yO return (hHook!=NULL);
T +5X0 Nv }
`k(yZtb BOOL UnInit()
s &Dg8$ {
W{z.?$SH if(nHookCount>1){
wIkN9
f nHookCount--;
}(a+aHH return TRUE;
O/:UJ( e{ }
)%rg?lI BOOL unhooked = UnhookWindowsHookEx(hHook);
G;>
_<22 if(unhooked==TRUE){
*"9><lJ-! nHookCount=0;
6cqP2!~ hHook=NULL;
bNT9 H`P }
l1ZY1#%j return unhooked;
aKU*j9A?;Z }
Q
4CjA3 #T`t79*N BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
8x`.26p {
xI,2LGO BOOL bAdded=FALSE;
Sxjub&= for(int index=0;index<MAX_KEY;index++){
l4T7'U>` if(hCallWnd[index]==0){
FZreP.2)! hCallWnd[index]=hWnd;
vVGDDDz/ HotKey[index]=cKey;
_%'},Xd.z HotKeyMask[index]=cMask;
1+b{}d bAdded=TRUE;
'|;X0fD KeyCount++;
'mI'dG break;
|AZg*T3:W }
yA{W }
R+gz<H.Q return bAdded;
f3`7tA }
Y*_)h\f <2C7<7{7 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
A!1;}x {
|t$Ma'P BOOL bRemoved=FALSE;
oYWR')8g for(int index=0;index<MAX_KEY;index++){
0G!]= if(hCallWnd[index]==hWnd){
9rh}1eo7 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
hdTzCfeZ5@ hCallWnd[index]=NULL;
%;#^l+UB HotKey[index]=0;
cj11S>D HotKeyMask[index]=0;
iy""(c bRemoved=TRUE;
:JlP[I
KeyCount--;
6TP7b| break;
4Llo`K4 }
lKk/p^: }
4k./(f2+ }
&.TTJsKG h return bRemoved;
R^{)D3 }
=4d (b ; HF|oBX$_ void VerifyWindow()
9Fn\FYUq {
[qsEUc+Z.' for(int i=0;i<MAX_KEY;i++){
V I%
6.6D if(hCallWnd
!=NULL){ U]a*uF~h
if(!IsWindow(hCallWnd)){ ){jla,[
hCallWnd=NULL; 8Lw B
B
HotKey=0; mf'V)
HotKeyMask=0; /VG2.:
KeyCount--; A'P(a`
} Fl(T\-Eu
} `y+tf?QN
} hy|b6wF&
} Z`YJBcXR
}i!J/tJ)b
BOOL CHookApp::InitInstance() Z|}G6]h
{ $XoQ]}"O
AFX_MANAGE_STATE(AfxGetStaticModuleState()); o M Zq+>
hins=AfxGetInstanceHandle(); U`hY{E;
InitHotkey(); F5S@I;
return CWinApp::InitInstance(); YKQr,
Now
} uwlr9nB
iiK]l
int CHookApp::ExitInstance() Sna4wkbS
{ }1IpON
VerifyWindow(); `({T]@]V
UnInit(); LR"9D
return CWinApp::ExitInstance(); K\|FQ^#UYm
} Ar~"R4!
HaIM#R32T
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file qWw\_S
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) $AHQmyg<
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ EqI(|bFwy
#if _MSC_VER > 1000 =-p$jXVW%
#pragma once 7g_]mG[6
#endif // _MSC_VER > 1000 P;4w*((} ~
w&ak"GgV
class CCaptureDlg : public CDialog O*#*%RL|
{ utr:J
// Construction ToYAW,U[d
public: 47J5oPT2'
BOOL bTray; r&FDEBh
BOOL bRegistered; Yw0[[N<SW
BOOL RegisterHotkey(); Ewg:HX7<(
UCHAR cKey; R##~*>#
UCHAR cMask; y!xE<S&Y
void DeleteIcon(); W^"AU;^V56
void AddIcon(); 8_N]e'WUh
UINT nCount; ;| 1$Q!4
void SaveBmp(); <tioJG{OT
CCaptureDlg(CWnd* pParent = NULL); // standard constructor
O#I1V K
// Dialog Data Sfdu`MQR
//{{AFX_DATA(CCaptureDlg) *g^x*|f6
enum { IDD = IDD_CAPTURE_DIALOG }; ,i@X'<;y
CComboBox m_Key; +@r*}
BOOL m_bControl; K$d$m <
BOOL m_bAlt; hJPlq0C
BOOL m_bShift; tsk)zP,<
CString m_Path; !F?XLekTi
CString m_Number; }\C-}
Q
//}}AFX_DATA &\_iOw8
// ClassWizard generated virtual function overrides -44l^}_u
//{{AFX_VIRTUAL(CCaptureDlg) j)q\9#sI/(
public: &4_qF^9J
virtual BOOL PreTranslateMessage(MSG* pMsg); i&n'N8D@
protected: /t(C>$ }p
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support cv`~y'?D
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); c%qv9
//}}AFX_VIRTUAL C`q@X(_
// Implementation ?Q&yEGm(
protected: _Zr.ba
HICON m_hIcon; b".L_Ma1*
// Generated message map functions <