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:
VII`qbxT
@lB1t=
D 一、实现方法
Nt+UL/1] R7Tl1!,h 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:
fo}@B&=4 N0fE*xo #pragma data_seg("shareddata")
ed,+Slg HHOOK hHook =NULL; //钩子句柄
,,XHw;{ UINT nHookCount =0; //挂接的程序数目
1slt[&4N static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Y\!:/h]E& static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
"~C\Z} ; static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
|RpZr!3V static int KeyCount =0;
qyyLU@hd static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
i_6 wD #pragma data_seg()
8Pom^QopK (`n*d3 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。
tSDp>0yZ3 E3Z>R=s 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:
-NG9?sI\U =L$RY2S" BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
"z.!h(Eq cKey,UCHAR cMask)
y^p%/p% {
@Ng q+uXm BOOL bAdded=FALSE;
j@Us7Q)A( for(int index=0;index<MAX_KEY;index++){
nkk GJV! if(hCallWnd[index]==0){
suj}A hCallWnd[index]=hWnd;
jaThS!>v HotKey[index]=cKey;
t[%=[pJHW HotKeyMask[index]=cMask;
QL(}k)dB bAdded=TRUE;
`).;W KeyCount++;
0txSF^x break;
y(#F&^| }
HSl$ U0 }
]*S_fme return bAdded;
uuhvd h= }
8DrKq]& //删除热键
(aCl*vV1 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
J! eVw\6 {
nfvs"B; BOOL bRemoved=FALSE;
I^A01\p for(int index=0;index<MAX_KEY;index++){
;rta#pRn if(hCallWnd[index]==hWnd){
FH H2 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
= &aD!nTx hCallWnd[index]=NULL;
.+AO3~Dg HotKey[index]=0;
ldoN!J HotKeyMask[index]=0;
~w%Z Bp bRemoved=TRUE;
,v1-y
?kB KeyCount--;
_jb"@TY break;
J2#=`|t" }
13{"sY:PT# }
{&(bKQ }
]O&A:Us return bRemoved;
Ip0@Q}^ }
;v+CQx OEGAwP?F oB Bdk@ DLL中的钩子函数如下:
5p{tt;9[ s: q15" LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
m9>nvrQ {
qXW2a'~ BOOL bProcessed=FALSE;
2|w.A! if(HC_ACTION==nCode)
u&I~%s {
~(0Y`+gC if((lParam&0xc0000000)==0xc0000000){// 有键松开
j'0*|f ^z switch(wParam)
/0YNB) {
Q+ST8 case VK_MENU:
KF-gcRh MaskBits&=~ALTBIT;
XY QUU0R break;
<ct {D|mm case VK_CONTROL:
U14dQ=~b/ MaskBits&=~CTRLBIT;
Z*e7W O. break;
1@qb.9wZ6 case VK_SHIFT:
7iJk0L$]x MaskBits&=~SHIFTBIT;
.r*b+rc;] break;
U ._1'pW default: //judge the key and send message
M[*:=C)H break;
01q7n`o#zf }
@%cJjZ5y for(int index=0;index<MAX_KEY;index++){
"RX?"pB if(hCallWnd[index]==NULL)
{}^ELw continue;
x!.VWG tb if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
FZ2-e {
(&hX8 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
qK1V!a2 bProcessed=TRUE;
(1}Ndo^;w }
?h3Ow`1G }
m<f{7]fi5 }
;qk~> else if((lParam&0xc000ffff)==1){ //有键按下
FW.dHvNX switch(wParam)
Q#r 0DWo\ {
/eMZTh*1P case VK_MENU:
o%9>elOju MaskBits|=ALTBIT;
xNqQbkF break;
ft6^s(t case VK_CONTROL:
pn7 :")Zx MaskBits|=CTRLBIT;
yEqmB4^- break;
X5/{Mx`8Oz case VK_SHIFT:
y?@Y\ b MaskBits|=SHIFTBIT;
I~qiF%?d break;
\j;uN#)28 default: //judge the key and send message
G-(c+6Mn break;
R39R$\ }
t(rU6miN for(int index=0;index<MAX_KEY;index++){
"=n8PNV/
c if(hCallWnd[index]==NULL)
_TXV{<E6 continue;
9iy|= if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
G\p;
bUF {
.-Lqo=o\ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
8W[]#~77b bProcessed=TRUE;
1;gSf.naG }
7Mv$.Z( }
VfcQibm }
) IhY&?jk? if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
c-=0l)&'D= for(int index=0;index<MAX_KEY;index++){
+=k|(8Js# if(hCallWnd[index]==NULL)
uRy6~' continue;
GKtQ>39B if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
LG|,g3& SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
L-R}O
8 //lParam的意义可看MSDN中WM_KEYDOWN部分
qU
n> }
Wu&Di8GhP }
y4L9Cxvs }
K)@}Ok"#\4 return CallNextHookEx( hHook, nCode, wParam, lParam );
A,e^bM
}
`x VA]GR4c \veL 5 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:
dZgfls 4"{wga~%/ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
%nh'F6bNgv BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
urB3 P[K=']c 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:
8!SiTOzR? B,Brmn LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
ix+x-G {
xlO2jSSAt if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
<6~;-ZQY
{
\pGO}{3e* //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
uCfp+ SaveBmp();
$@kw>2 return FALSE;
[ d7]&i}*| }
<pUou …… //其它处理及默认处理
<;e#"(7 }
XE*bRTEw *^Y0}?]qT |=T<WU1$ 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。
`=DCX%Vw 8|NJ(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。
"%t`I) r_E)HL/A 二、编程步骤
U.'@S8 n;`L5 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";
5z ^UQq 9%14k 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
~{G:,|` F5MPy[ 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;
9 lJj/ \=_q{ 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;
^(*O$N*# )6
<byO 5、 添加代码,编译运行程序。
!cwVJe 3og$'#6P 三、程序代码
a3O_#l-Z u/'sdt ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
_ng= 5 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
C}'="g^=sl #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
Ef!p:HBJ #if _MSC_VER > 1000
gdE `UZ\ #pragma once
>1G*ya) #endif // _MSC_VER > 1000
p30&JJ!~" #ifndef __AFXWIN_H__
/t)c fFM #error include 'stdafx.h' before including this file for PCH
~"2@A
F #endif
~!9Px j* #include "resource.h" // main symbols
yGGB class CHookApp : public CWinApp
p3FnYz-V {
vcO`j<` public:
\N , ' + CHookApp();
8Vhck-wF // Overrides
X6GkJ
R // ClassWizard generated virtual function overrides
+JS/Z5dl+} //{{AFX_VIRTUAL(CHookApp)
6n\z53Mk public:
A'QGTT virtual BOOL InitInstance();
Wx)U<:^e virtual int ExitInstance();
fR%1FXpK& //}}AFX_VIRTUAL
qK
vr*xlC //{{AFX_MSG(CHookApp)
hUvuq,LH_ // NOTE - the ClassWizard will add and remove member functions here.
3;S`< // DO NOT EDIT what you see in these blocks of generated code !
?VP!1O=J //}}AFX_MSG
yL
x .#kx6 DECLARE_MESSAGE_MAP()
vSC0D7BlG };
OrEuQ-,i@ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
k5;Vl0Ho BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
KI@ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
xf"5<PTW</ BOOL InitHotkey();
E+ 3yN\X( BOOL UnInit();
Df:7P> #endif
A
a} o* uoY`qF.` //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
_pko]F|() #include "stdafx.h"
Vy^yV|`v #include "hook.h"
3u0<v%Qi #include <windowsx.h>
/dJ)TW(Ir #ifdef _DEBUG
#t2UPLO~ #define new DEBUG_NEW
]ZzG!7 #undef THIS_FILE
q6JW@GT static char THIS_FILE[] = __FILE__;
Xu94v{u3 #endif
Z<|_+7T #define MAX_KEY 100
Iei7!KLW #define CTRLBIT 0x04
wEnuUC4j #define ALTBIT 0x02
=ch
Af= #define SHIFTBIT 0x01
~K-*q{6Q #pragma data_seg("shareddata")
m_!vIUOz HHOOK hHook =NULL;
Jp3di&x UINT nHookCount =0;
&M3ES}6 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
H]$=*(aje static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
+iH30v static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
Jhsv2,8
{ static int KeyCount =0;
ca/o#9:N`: static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
yaRcBT? #pragma data_seg()
!\#Wk0Ku HINSTANCE hins;
%:w% o$ void VerifyWindow();
"4ozlWx BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
"vOfAo]` //{{AFX_MSG_MAP(CHookApp)
`,Y[ Z // NOTE - the ClassWizard will add and remove mapping macros here.
0YpiHoM // DO NOT EDIT what you see in these blocks of generated code!
Yl&tkSw46 //}}AFX_MSG_MAP
FfxX)p1t END_MESSAGE_MAP()
IFrb}yH GtM(
Y CHookApp::CHookApp()
7}'A)C>J; {
o d}EM_ // TODO: add construction code here,
vf'cx:m // Place all significant initialization in InitInstance
OVUs]uK }
{nQ)4.e6 S}w.#tyEn CHookApp theApp;
@bW[J LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
v-;XyVx {
\%Ah^U)gS BOOL bProcessed=FALSE;
=qp}p'BYe if(HC_ACTION==nCode)
lQdnL.w$.4 {
6/mkJj+" if((lParam&0xc0000000)==0xc0000000){// Key up
|ON&._`LH switch(wParam)
i,'Ka[6
{
O| 1f^_S/ case VK_MENU:
xdL/0 N3 MaskBits&=~ALTBIT;
50`iCD break;
EO].qN-8
case VK_CONTROL:
X$- boe? MaskBits&=~CTRLBIT;
"s>fV9YyZ break;
2fzKdkJhe case VK_SHIFT:
%R5Com MaskBits&=~SHIFTBIT;
fys5-1@-p break;
y^X\^Kq
default: //judge the key and send message
XJmFJafQD break;
&gA6+b' }
29Z!p2{hk for(int index=0;index<MAX_KEY;index++){
3"'# |6O9 if(hCallWnd[index]==NULL)
bvipbf[m< continue;
nxyjL)!)0 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
/i{tS`[F2a {
~IlF*Zz#}6 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
:vYtMp bProcessed=TRUE;
>,>;)B@J }
aJ6#=G61l }
s-C!uq }
kUn2RZ6$# else if((lParam&0xc000ffff)==1){ //Key down
llHc=&y# switch(wParam)
.Na&I)udX. {
S9HBr case VK_MENU:
-}Cc"qm MaskBits|=ALTBIT;
}z%OnP break;
selP=Q! case VK_CONTROL:
rb:<N%*t MaskBits|=CTRLBIT;
1KTabj/C break;
@PPR$4 case VK_SHIFT:
a{]g+tGH MaskBits|=SHIFTBIT;
l_c^ .D break;
" WYA default: //judge the key and send message
v)@,:u) break;
Pqy-gWOv }
N>d|A]zH for(int index=0;index<MAX_KEY;index++)
,4H;P/xsb {
i1qS ns if(hCallWnd[index]==NULL)
Jo{zy continue;
mb0n}I_AC if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Ky[bX {
T!l
mO? Q SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
[3j$ 4rP bProcessed=TRUE;
[8F
\; }
LkJ$aW/ }
T&1-eq>l }
]urK$ if(!bProcessed){
2#z=zd for(int index=0;index<MAX_KEY;index++){
Qm.z@DwFM{ if(hCallWnd[index]==NULL)
;W7 hc! continue;
mi7sBA9L8 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
l^k+E-w\ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Mjb 1 }
/ <JY:1| }
5oz>1 }
ow2M,KU6Z return CallNextHookEx( hHook, nCode, wParam, lParam );
6xQ"bFm }
sA/,+aM [O^}rUqq BOOL InitHotkey()
0TTIaa$ {
CE~r4 if(hHook!=NULL){
f%2%T'Q nHookCount++;
hzaLx8L return TRUE;
9;=q=O/ }
Ur^YG4( else
bt;lq!g hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
fd4;mc1T if(hHook!=NULL)
/@&(P#h nHookCount++;
`$J'UXtGc return (hHook!=NULL);
/ ^w"' ' }
I+0c8T(: BOOL UnInit()
mT96]V\ {
eh$G.-2N if(nHookCount>1){
XjX 2[*l nHookCount--;
+.w[6 return TRUE;
@. "q }
c#=&!FRe BOOL unhooked = UnhookWindowsHookEx(hHook);
X(IyvfC if(unhooked==TRUE){
D899gGe nHookCount=0;
43KaL( hHook=NULL;
+Dv 7:x7 }
e\`wlaP, return unhooked;
z~F37]W3[ }
p`
$fTgm Jf2e<?` BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
I?^aCnU {
&a.']!$^" BOOL bAdded=FALSE;
!?jK1{E3 for(int index=0;index<MAX_KEY;index++){
+<&E3O r if(hCallWnd[index]==0){
nt7|f,_J hCallWnd[index]=hWnd;
;:P7}v fz! HotKey[index]=cKey;
>GgE,h HotKeyMask[index]=cMask;
R0{Qy*YQ` bAdded=TRUE;
!6lOIgn KeyCount++;
^D>fis break;
]* 0(-@ }
19'5Re& }
+6
ho)YL return bAdded;
U<Vy>gIC }
X1Qr_o-BR ThtMRB)9 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
6_WmCtvF {
7m\vRMK BOOL bRemoved=FALSE;
-!l^]MU for(int index=0;index<MAX_KEY;index++){
L${m/@9 if(hCallWnd[index]==hWnd){
:WVSJ,. ! if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
OZ=Cp$ hCallWnd[index]=NULL;
f_rp<R>Uu HotKey[index]=0;
6Z Xu,ks} HotKeyMask[index]=0;
x.ba|:5 bRemoved=TRUE;
hqL+_|DW KeyCount--;
8yn4}`Nc@ break;
0 <g{ V }
)Bo]=ZTJ^ }
gSb,s [p&+ }
)T9~8p. return bRemoved;
P/G>/MD/l }
GLCAiSMz[ rkq#7 void VerifyWindow()
Y~}5axSPH {
"mR*7o$| for(int i=0;i<MAX_KEY;i++){
+>!V]S if(hCallWnd
!=NULL){ SnW7 x
if(!IsWindow(hCallWnd)){ Hte[TRbM
hCallWnd=NULL; ]w!0u2K<Q\
HotKey=0; )9B:Y;>)
HotKeyMask=0; FNC[59
KeyCount--; 1eHe~p ,
} i3P9sdTD
} Hs$'0:
} `^x9(i/NE
} H'Nq#K
-G-3q6A
BOOL CHookApp::InitInstance() tF^g<)S;t
{ ~ltg
AFX_MANAGE_STATE(AfxGetStaticModuleState()); `]jqQr97
hins=AfxGetInstanceHandle(); o5SQ1;`
InitHotkey(); myIe_k,F
return CWinApp::InitInstance(); J1X~vQAe
} OM)3Y6rK
V#L'7">VP
int CHookApp::ExitInstance() zW5C1:.3K
{ b1xpz1
VerifyWindow(); &))\2pl
UnInit(); 0elxA8Z~e
return CWinApp::ExitInstance(); vQgq]mA?
} BZ+;n
|<r
6WeM rWx
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file !p',Za
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 7\X$7
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ {~_Y _-
#if _MSC_VER > 1000 Rk A8
#pragma once WI&lj<*
#endif // _MSC_VER > 1000 gw+eM,Yp
gfN2/TDC]P
class CCaptureDlg : public CDialog epkD*7
{ w#9_eq|3
// Construction n'M>xq_
public: w"~<h;
BOOL bTray; )c+k_;t'+
BOOL bRegistered; UFw](%=&M
BOOL RegisterHotkey(); 2"X~ju
UCHAR cKey; [Gtb+'8
UCHAR cMask; "(f`U.
void DeleteIcon(); "}zt`3
void AddIcon(); <<,>S&/
UINT nCount; nQ-mmY>#
void SaveBmp(); )R &,'`\
CCaptureDlg(CWnd* pParent = NULL); // standard constructor p0VUh!
// Dialog Data uR:rO^
//{{AFX_DATA(CCaptureDlg) ||Y<f *
enum { IDD = IDD_CAPTURE_DIALOG }; ~=cmM
CComboBox m_Key; S&wzB)#'
BOOL m_bControl; S-c ^eLzQ
BOOL m_bAlt; }`_(<H
BOOL m_bShift; 2 hq\n<
CString m_Path; cP rwW6
CString m_Number; IZrk1fh
//}}AFX_DATA t,<UohL|z
// ClassWizard generated virtual function overrides (>7>3
//{{AFX_VIRTUAL(CCaptureDlg) >bIF>9T
public: Y3rt5\!
virtual BOOL PreTranslateMessage(MSG* pMsg); 9 <\`nm
protected: PVYyE3`UB
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support #
yN*',I&
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); !%[S49s
//}}AFX_VIRTUAL ].m qxf
// Implementation o35fifM`
protected: 6Hf,6>
HICON m_hIcon; [Y/:@t"2y
// Generated message map functions zk}{ dG^M:
//{{AFX_MSG(CCaptureDlg) G%:GeW
virtual BOOL OnInitDialog(); &