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~L&c
R$X~d8o>% 一、实现方法
+pRNrg?k A `{hKS 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
}O Y/0p-Z XY#.?<"Q8 #pragma data_seg("shareddata")
X|-[i hp; HHOOK hHook =NULL; //钩子句柄
RqX^$C8M UINT nHookCount =0; //挂接的程序数目
0j;q^> static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
yd=b!\}WJ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
dci<Rz`h static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
m?kyAW'| static int KeyCount =0;
[ ou$* static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
y @S_CB47 #pragma data_seg()
iX[g k.z(.uc= 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
<RKT
| "}V_.I*+ DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
IC?(F]$%> u*/+cT BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
uP+VS>b cKey,UCHAR cMask)
+Qf}&D_ {
*YSRZvD<\ BOOL bAdded=FALSE;
|nE4tN#J< for(int index=0;index<MAX_KEY;index++){
/3&MUB*z&y if(hCallWnd[index]==0){
SA7(EJ95 hCallWnd[index]=hWnd;
Re&"Q8I.8 HotKey[index]=cKey;
M*f]d`B HotKeyMask[index]=cMask;
P?S]Q19Q4 bAdded=TRUE;
s VHk;:e>x KeyCount++;
sn"z'=ch break;
.G#li(NWH }
hD=.rDvO }
bF6J>&]! return bAdded;
}wkY`" }
yM~bUmSg //删除热键
FWA?mde BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
$1g1Bn {
C!|LGzs0 BOOL bRemoved=FALSE;
YZ`SF"Bd( for(int index=0;index<MAX_KEY;index++){
tj$[szo if(hCallWnd[index]==hWnd){
s&Y"a,|Z if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
K8R>O *~ hCallWnd[index]=NULL;
-Caj>K HotKey[index]=0;
Q;J(
5; HotKeyMask[index]=0;
?xrOhA9 bRemoved=TRUE;
7B)1U_L0H KeyCount--;
d$jwh(Ivs break;
}opw_h+/F }
aydNSgu }
^H&U_ }
g/fpXO\ return bRemoved;
k%FA:ms|k }
+FAj30 s8)`wH? ypyKRsx DLL中的钩子函数如下:
/0 4US5En u>n"FL'e LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
a]T&-#c,} {
BjeD4 BOOL bProcessed=FALSE;
Lm=;Y6'`N if(HC_ACTION==nCode)
X fqhD&g {
fP V n; if((lParam&0xc0000000)==0xc0000000){// 有键松开
?:ZB'G{%E switch(wParam)
<l$ d>, {
X.#)CB0c1Q case VK_MENU:
P6R_W MaskBits&=~ALTBIT;
RFyMRE!? break;
#,u|*O: case VK_CONTROL:
z V\+za, MaskBits&=~CTRLBIT;
BqY_N8l&E break;
wV"`Du7E; case VK_SHIFT:
"J`&"_CyZ MaskBits&=~SHIFTBIT;
+l/v`=C break;
CF2Bd:mfZ default: //judge the key and send message
:Ys~Lt54 break;
VOLj#H }
l6&\~Z( for(int index=0;index<MAX_KEY;index++){
avL_>7q if(hCallWnd[index]==NULL)
=jJEl=*S continue;
C!*.jvhT if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
\1Xk[% {
dniU{v SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
eM:J_>7t bProcessed=TRUE;
Iz5NA0[=2 }
8v4 o+wP }
#5Z`Q^ }
X
3$ W60Q else if((lParam&0xc000ffff)==1){ //有键按下
yjg&/6 switch(wParam)
6FQi=}O 1 {
8.#{J&h case VK_MENU:
s:Ml\['x MaskBits|=ALTBIT;
+7^p d9F. break;
1J4Pnl+hN case VK_CONTROL:
+ti ?7|bK< MaskBits|=CTRLBIT;
j
0pI break;
[YfoQ1 case VK_SHIFT:
wDZ<UP=X MaskBits|=SHIFTBIT;
/N"3kK,N break;
UnF8#~ default: //judge the key and send message
/v8Q17O?e break;
IB/3=4n^| }
*iEtXv for(int index=0;index<MAX_KEY;index++){
Y~-y\l;Tr if(hCallWnd[index]==NULL)
Ve3z5d:^ continue;
UtQey ;w if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
>F7w]XH {
>sfg`4 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
>H!Mx_fDL bProcessed=TRUE;
BVNW1<_: }
#_@cI(P }
3KkfQ{ }
xi=ApwNj if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
pn
gto for(int index=0;index<MAX_KEY;index++){
TZAd{EZa if(hCallWnd[index]==NULL)
~,b^f{7`! continue;
t?W}=%M[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
ViPC Yt`of SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
X#lNS+&=' //lParam的意义可看MSDN中WM_KEYDOWN部分
P5h|* ?= }
.B#
.
}
(Q^sK\ }
DK)W
,z| return CallNextHookEx( hHook, nCode, wParam, lParam );
K^shT h8k }
4hL%J=0: Yf w>x[#e 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:
4VWk/HK-! ZgP%sF BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
uZS : BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
CJBf5I3 -{cHp 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:
6Dlm.~G xzOa9w/ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
=|S%Rzsk {
3/kT'r if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
}}JMwT
{
=?<WCR
C* //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
`Vb SaveBmp();
]:<!( return FALSE;
h[ DNhR }
T{k
P9
4 …… //其它处理及默认处理
<v:VA!] }
5ilGWkb`'X H5=kDkb }02`ve* 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。
9\?OV@ B `~EA] d 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。
^Xk!wJ I&;>(@K 二、编程步骤
P[nc8z[
~[g(@Xt 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";
21uK&nVf^l OSgJj MQ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
)'_[R@ThB b(H{i}{] 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;
rs&]46i/p q$Gs;gz^( 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
B0fOAP1 n~N>;mP 5、 添加代码,编译运行程序。
]gk1q{Ql< Zd*$^P,| 三、程序代码
};/QK* Rh!UbEPjC ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
:
\+xXb{ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
>XD?zF)6 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
{3~VLdy #if _MSC_VER > 1000
2Je$SE8 #pragma once
pP. _%5 #endif // _MSC_VER > 1000
d7OygDb < #ifndef __AFXWIN_H__
8Bf> #error include 'stdafx.h' before including this file for PCH
3Vb4zZsl #endif
_4ag-'5 #include "resource.h" // main symbols
6>>; fy2 class CHookApp : public CWinApp
Kc/1LeAik {
-aoYoJ ' public:
4T@:_G2b CHookApp();
_gvFs%J // Overrides
iNO>'7s7 // ClassWizard generated virtual function overrides
37#&:[w> //{{AFX_VIRTUAL(CHookApp)
_C?j\Wy public:
LW %AZkAx virtual BOOL InitInstance();
:QE5 7. virtual int ExitInstance();
+\/Q //}}AFX_VIRTUAL
|VBt:dd< //{{AFX_MSG(CHookApp)
Yh":>~k?SY // NOTE - the ClassWizard will add and remove member functions here.
{ZJO5* // DO NOT EDIT what you see in these blocks of generated code !
9BCW2@Kp //}}AFX_MSG
=kjKK DECLARE_MESSAGE_MAP()
>rSjP1-F };
bjZJP\6 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
067c/c BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
z5+Pi:1w BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
+HK4sA2; BOOL InitHotkey();
a~$XD(w^ BOOL UnInit();
yk+ 50/L #endif
9mF' K`4rUEf}V" //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
/F*Y~>*% 1 #include "stdafx.h"
h [TwaR #include "hook.h"
ewZ?+G+m #include <windowsx.h>
2w?q7N% #ifdef _DEBUG
44]s`QyG #define new DEBUG_NEW
|.<_$[v[x #undef THIS_FILE
p~pD`'% static char THIS_FILE[] = __FILE__;
]g_VPx" #endif
6#=jF[ #define MAX_KEY 100
*Rgr4-eS #define CTRLBIT 0x04
H|9t5
#define ALTBIT 0x02
Lkt4F #define SHIFTBIT 0x01
:ym?]EL4o #pragma data_seg("shareddata")
SeX ]|?D HHOOK hHook =NULL;
#EzBB*kP
UINT nHookCount =0;
Dd3f@b[WX static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
q6
CrUn static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
!b8V&< static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
F'bwXb** static int KeyCount =0;
-^_m(@A<~ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
"F
F$Q#) #pragma data_seg()
_jWs(OmJ HINSTANCE hins;
`MtzA^X r void VerifyWindow();
8fC4j`! BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
g}an
5a //{{AFX_MSG_MAP(CHookApp)
/<LZt<K // NOTE - the ClassWizard will add and remove mapping macros here.
e~r/!B5X // DO NOT EDIT what you see in these blocks of generated code!
^&zCPUH //}}AFX_MSG_MAP
=|t-0'RsN END_MESSAGE_MAP()
UhxM85M;x X Xque- CHookApp::CHookApp()
dkQ4D2W*\ {
TCr4-"`r-{ // TODO: add construction code here,
Ln"wjO, // Place all significant initialization in InitInstance
du65=w4E! }
"J VIkC m%'nk"p9 CHookApp theApp;
s :vNr@TS LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
qBA)5Sv\V {
N5Js.j>z BOOL bProcessed=FALSE;
_&gi4)q if(HC_ACTION==nCode)
z7K{ ,y {
*ap,r&]#F if((lParam&0xc0000000)==0xc0000000){// Key up
(q)}`1d' switch(wParam)
eYOY {
z.vQ1~s case VK_MENU:
6h 0qtXn- MaskBits&=~ALTBIT;
_`$Q6!Z)l break;
A*JOp8\) case VK_CONTROL:
/{T&l*' MaskBits&=~CTRLBIT;
iaGA9l<b break;
N*Y[[N( case VK_SHIFT:
K-qWT7< MaskBits&=~SHIFTBIT;
X5 vMY break;
,jU>V]YC default: //judge the key and send message
GQ2GcX(E( break;
+^.Yt0} }
umYsO.8 for(int index=0;index<MAX_KEY;index++){
TdhfX {nk if(hCallWnd[index]==NULL)
TxrW69FV7 continue;
crmQn ^4\ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
W .a>K$ {
byHc0ktI\ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
i3-5~@M bProcessed=TRUE;
)aS:h}zn }
Q*DT" W/0 }
4:/]Y=)x }
V!}I$JiJ else if((lParam&0xc000ffff)==1){ //Key down
Y}~sTuWU switch(wParam)
>xWS>
{
`3TR`,= case VK_MENU:
7B?Y.B MaskBits|=ALTBIT;
7)?C+=,0 break;
H2X_WSwm case VK_CONTROL:
w$]G$e MaskBits|=CTRLBIT;
kmQ:wf: break;
_c5@)I~ case VK_SHIFT:
[2:d@=%. MaskBits|=SHIFTBIT;
ZO+RE7f*?c break;
l*CulVX default: //judge the key and send message
g2OnLEF]s break;
pPReo) }
]_KWN$pd for(int index=0;index<MAX_KEY;index++)
vYgJu-Sl {
_i=*0Q if(hCallWnd[index]==NULL)
Z{8%Cln continue;
* #yF`_p if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
K\xz|Gq {
V@'Xj .ze SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
`M@ESA(e bProcessed=TRUE;
p=+Y7NE) }
[(X~C*VdxM }
0h-NT\m }
gtKih if(!bProcessed){
O,$*`RZpx for(int index=0;index<MAX_KEY;index++){
fB2ILRc if(hCallWnd[index]==NULL)
FZ*"^=)`G continue;
" ityx? if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
CD1Ma8I8 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
R|?n }
Np\NStx2 }
snbXAx1L }
#}A"yo return CallNextHookEx( hHook, nCode, wParam, lParam );
={g"cx }
Et6j6gmif q<}IO BOOL InitHotkey()
h#1:ypA6l {
[^"}jbn/ if(hHook!=NULL){
)nd^@G^ nHookCount++;
vJE=H9E return TRUE;
*|&Y ,H? }
g *5_m(H else
g[cnaS|? hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
u#6s^
)W if(hHook!=NULL)
[s}W47N1 nHookCount++;
!@C-|=9G return (hHook!=NULL);
Zpd-ob }
#}Qe{4L BOOL UnInit()
/_{-~0Z=@B {
T;u;r@R/ if(nHookCount>1){
w1Bkz\95 nHookCount--;
rCJ$Pl9R return TRUE;
.ATpwFal }
3.movkj BOOL unhooked = UnhookWindowsHookEx(hHook);
?e%*q^~Cu if(unhooked==TRUE){
*r.%/^@ nHookCount=0;
+2[0q% i hHook=NULL;
9KK^1<46c }
RHsVG &<j return unhooked;
[3dGHf;miw }
@(R=4LL g0 f4>m BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
VEV?$R7; {
1 |z4]R,< BOOL bAdded=FALSE;
y[J9"k(@ for(int index=0;index<MAX_KEY;index++){
XT/t\\Z`U if(hCallWnd[index]==0){
:EW1I>}_ hCallWnd[index]=hWnd;
RFM;?!S HotKey[index]=cKey;
A6z2KVk HotKeyMask[index]=cMask;
S{llpp{E bAdded=TRUE;
1
-Z&/3T] KeyCount++;
O0}uY:B break;
4(8c L?J`0 }
IlJ"t`Z9) }
NXD- return bAdded;
y,?=,x}o# }
>4g!ic~O \7\sx:!$ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
c{^1`(#? {
=2q#- ,t BOOL bRemoved=FALSE;
S6bW
r0XR for(int index=0;index<MAX_KEY;index++){
rL<N:@HL if(hCallWnd[index]==hWnd){
<ppdy,j: if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
4{>r_^8 hCallWnd[index]=NULL;
A}"|_&E HotKey[index]=0;
we}xGb.u HotKeyMask[index]=0;
dPO"8HQ bRemoved=TRUE;
CLND[gc KeyCount--;
0}GO$%l break;
7<LuL }
YM#'+wl}` }
Av.`'.b }
1PVZGZxAgv return bRemoved;
Z71_D }
}:?*n:g5 DXJw)%G
w void VerifyWindow()
y/@Bhzc {
&q&z$Gc;m for(int i=0;i<MAX_KEY;i++){
yR5XcPoKI if(hCallWnd
!=NULL){ }
e w{WD
if(!IsWindow(hCallWnd)){ \HxF?i "
hCallWnd=NULL; RZEq@q
HotKey=0; zMepF]V
HotKeyMask=0; |keU+De
KeyCount--; ?121 as}z
} '7' 73
} <Z[Z&^
} SN|!FW.*:
} AK
lra$
|Ja5O
BOOL CHookApp::InitInstance() qo:Zc`t(R
{ {^
BZ#)m|
AFX_MANAGE_STATE(AfxGetStaticModuleState()); zEjl@Kf
hins=AfxGetInstanceHandle(); xTk6q*NvT^
InitHotkey(); ]G&[P8hzB
return CWinApp::InitInstance(); 'h ?
} /@Jg [na
^G qO>1U
int CHookApp::ExitInstance() xqdkc^b
{ ?Kmz urG
VerifyWindow(); NI/'SMj%
UnInit(); @Y,t]
return CWinApp::ExitInstance(); wg_Z@iX
} #++:`Z
;+DMv5A "
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file u;%~P 9O
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 0rX%z$D+@
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ ;7[DFlS\P
#if _MSC_VER > 1000 .`*;AT
#pragma once `C7pM
#endif // _MSC_VER > 1000
wBlE!Pm
J<NpA(@^
class CCaptureDlg : public CDialog ZT"vVX-)G
{ o^5UHFxTCB
// Construction g[y&GCKY!=
public:
Ce//;Op
BOOL bTray; @@a#DjE%/
BOOL bRegistered; 5~>j98K
BOOL RegisterHotkey(); ~Y0K Wx4
UCHAR cKey; ;"f9"
UCHAR cMask; f*V^HfiQb
void DeleteIcon(); io"NqR#"v
void AddIcon(); EAh|$~X
UINT nCount; |+~P; fG
void SaveBmp(); O*2{V]Y
@
CCaptureDlg(CWnd* pParent = NULL); // standard constructor +-x+c:
IxA
// Dialog Data /_JR7BB^X,
//{{AFX_DATA(CCaptureDlg) I+Y Z+
enum { IDD = IDD_CAPTURE_DIALOG }; RYl{89
CComboBox m_Key; cEXd#TlY~X
BOOL m_bControl; <`q-#-V@
BOOL m_bAlt; w3iX "w
BOOL m_bShift; j0F&
W Kk
CString m_Path; I(>_as\1
CString m_Number; ]c\`EHN
//}}AFX_DATA f&F9ImZ
// ClassWizard generated virtual function overrides >y}> 5kv
//{{AFX_VIRTUAL(CCaptureDlg) 7u1o>a%9
public: bTx4}>=5l
virtual BOOL PreTranslateMessage(MSG* pMsg); A\"4[PXpQ
protected: XYV`[,^h&
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support $v8T%'p+
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); 3]NKAPY
//}}AFX_VIRTUAL Q=<&ew
// Implementation u3cg&lEgT
protected: >7?Lq<H
HICON m_hIcon; 0/fwAp
// Generated message map functions F&k<