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:
`Frr?.3&-
VaW^;d# 一、实现方法
@#p6C 8B(=Y;w 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:
P6I<M}p l>?f+70 #pragma data_seg("shareddata")
R/xT.EQ(N HHOOK hHook =NULL; //钩子句柄
zM(-f|wVI) UINT nHookCount =0; //挂接的程序数目
BM{*5Lf static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
drxCjuz" static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
>"+ho static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
gZ|!' static int KeyCount =0;
|[0Ijm2 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
Ncr Bp( #pragma data_seg()
kLF~^/ o`Af6C;Q 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。
NM9,AG BCuoFw) 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:
{b' UpPl-jeT BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
BaWU[* cKey,UCHAR cMask)
%
H<@Y$r {
P+Gz' BOOL bAdded=FALSE;
@^<&LG5^ for(int index=0;index<MAX_KEY;index++){
tZv^uuEp3 if(hCallWnd[index]==0){
X`3_ yeQc hCallWnd[index]=hWnd;
6oq5CD oq HotKey[index]=cKey;
~;z]
_`_Va HotKeyMask[index]=cMask;
"TP~TjXfq bAdded=TRUE;
(?g+.]Dt, KeyCount++;
1KY0hAx break;
lU%oU&P/"S }
Qv`: E }
q7rb3d return bAdded;
en/ h`h]h }
jo0XF] //删除热键
pY[b[ezb BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
$P#x>#+[A {
_BY+Tfol BOOL bRemoved=FALSE;
# S/n3 for(int index=0;index<MAX_KEY;index++){
'sXrtl7{^ if(hCallWnd[index]==hWnd){
g4Q' Fub+I if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
B'Jf&v hCallWnd[index]=NULL;
EADN HotKey[index]=0;
ul~6zBKO HotKeyMask[index]=0;
`d^Q!QxE bRemoved=TRUE;
{]cr.y]\ KeyCount--;
:4-,Ru1C" break;
uY(8KW }
,Jh#$mil }
3[y$$qXI }
\+nV~Pi"A return bRemoved;
~Kt1%&3{a? }
*r[V[9+y-D SD :D8"8 i-w$-2w DLL中的钩子函数如下:
vb?.`B_>& T9%|B9FeJ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
.)$MZyo {
(&Jo.
< BOOL bProcessed=FALSE;
NN2mOJ:- if(HC_ACTION==nCode)
.D ^~!A {
AX$r,KmE if((lParam&0xc0000000)==0xc0000000){// 有键松开
{| hg3R~A switch(wParam)
9Q}g
Vqn {
akt7rnt?i case VK_MENU:
yyljyE MaskBits&=~ALTBIT;
lct break;
o+}k$i!6 case VK_CONTROL:
~tt\^:\3~S MaskBits&=~CTRLBIT;
$A9Pi"/*z break;
HUD0
@HQI case VK_SHIFT:
D-LOjMe MaskBits&=~SHIFTBIT;
jk&xzJH. break;
RZV6;=/ default: //judge the key and send message
u>.a; BO break;
_qf39fM;\ }
,lA@C2c for(int index=0;index<MAX_KEY;index++){
#:0-t!<0C if(hCallWnd[index]==NULL)
X*@ tp,t continue;
o
?vGI= if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
AK,'KO%{= {
r!dWI SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
~`QoBZ.O& bProcessed=TRUE;
PIa!NPy }
vE'{?C=EM }
(1[59<cg] }
z/xPI)R[ else if((lParam&0xc000ffff)==1){ //有键按下
GnW MI1$ switch(wParam)
ceE]^X;p {
g assOd case VK_MENU:
lP`BKc, MaskBits|=ALTBIT;
=/46;844T break;
').)0; case VK_CONTROL:
}q@#M8 b MaskBits|=CTRLBIT;
|K Rt$t break;
;\2Z?Kq case VK_SHIFT:
dREY m}1 MaskBits|=SHIFTBIT;
2L 1,; break;
ft(o-f7, default: //judge the key and send message
Pn OWQ8= break;
4)8VmCW }
%r(WS_%K| for(int index=0;index<MAX_KEY;index++){
{IV%_y? if(hCallWnd[index]==NULL)
ulIEx~qP continue;
6EyPZ{ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
s/IsrcfM {
'1ySBl1> SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
NgGMsE\C} bProcessed=TRUE;
/VT/KT{ }
YkWHI(p }
lfcGi3 }
2r!ltG3} if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
i)z|=
|? for(int index=0;index<MAX_KEY;index++){
&su'znLV if(hCallWnd[index]==NULL)
EYq?NL=' continue;
,O5X80'.g if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
hHE~/U SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
f?sm~PwC- //lParam的意义可看MSDN中WM_KEYDOWN部分
`sCaGCp }
c,2& -T} }
YK3>M"58 }
Kt_oo[ey{ return CallNextHookEx( hHook, nCode, wParam, lParam );
:'Qiwf& }
ux&"TkEp JkAM:,^( 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:
uPz+*4+
QPx5`{nN BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
I$xZV?d. BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
tbRW6 c
3QgX4vq 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:
Z;.-UXat |NfFe*q0;8 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
=*,SD {
%PYl if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
r.H`3m.0q {
.zO2g8(VR //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
a+^`+p/5 SaveBmp();
S:_Ms{S return FALSE;
%F>~2g?$ }
S 5S\zTPIf …… //其它处理及默认处理
Kq")\Ha,f }
!!1?2ine *DF3juf~ )5Khl"6!z 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。
JY0aE RPz[3y 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。
!/is+
xp 9jkz83/+< 二、编程步骤
ZLkl:'E_ Ia&*JYM[ 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";
}e[ E }\"EI<$s 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
'$tCAS Ww]$zd-bo 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;
rQjk
7OV^>"S 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;
RaJTya^ CY1WT 5、 添加代码,编译运行程序。
yE$PLM `fBQ?[05. 三、程序代码
\<LCp;- K \QvGkcDc{ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
uC'-: t# #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
!7N:cx'Qy #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
l;; 2\mL? #if _MSC_VER > 1000
DSrU7# #pragma once
Y+?QHtZL #endif // _MSC_VER > 1000
8Y`Lq$u #ifndef __AFXWIN_H__
dfDjOZSL #error include 'stdafx.h' before including this file for PCH
&tyS 6S+ #endif
/UCBoQ$/] #include "resource.h" // main symbols
E)v~kC}7. class CHookApp : public CWinApp
_{*} )&!M {
5GsmBf$RUb public:
}LUvh CHookApp();
d<m;Q}/l&h // Overrides
Za|7gt];l // ClassWizard generated virtual function overrides
V}E['fzBFV //{{AFX_VIRTUAL(CHookApp)
"#d$$ 8 public:
i fsh(^N virtual BOOL InitInstance();
km%r{ virtual int ExitInstance();
)PYPlSQ*V //}}AFX_VIRTUAL
Aiq Kf= //{{AFX_MSG(CHookApp)
A(y6]E! // NOTE - the ClassWizard will add and remove member functions here.
XcJ5KTn // DO NOT EDIT what you see in these blocks of generated code !
K;
#FU //}}AFX_MSG
e{)giJY9 DECLARE_MESSAGE_MAP()
i$Y#7^l%k };
l)u%`Hcn LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
lu#a.41 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
t^#1=nK BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
x;mw?B[ BOOL InitHotkey();
e,(Vy BOOL UnInit();
> X~\(|EM #endif
}<Ydj .85 Kzev] er //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
]3,'U(!+ #include "stdafx.h"
Es=G' au #include "hook.h"
bb_elmb)n #include <windowsx.h>
*l7 `C) #ifdef _DEBUG
x?i
wtZ@ #define new DEBUG_NEW
Y.m1d ?H 1 #undef THIS_FILE
"im5Fnu static char THIS_FILE[] = __FILE__;
4MC]s~n #endif
@]Q4K%1^" #define MAX_KEY 100
o$@/@r #define CTRLBIT 0x04
M6-uTmN:d #define ALTBIT 0x02
+w0Wg.4V #define SHIFTBIT 0x01
8@3=SO #pragma data_seg("shareddata")
tB;PGk_6 HHOOK hHook =NULL;
r\m{;Z#LJm UINT nHookCount =0;
~}OaX+! static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
$1=7^v[U static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
c&;" Y{ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
7FwtBO static int KeyCount =0;
yzEyOz@Q static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
fw %p_Cm #pragma data_seg()
ZK4V-?/[6 HINSTANCE hins;
g}~s"Sz void VerifyWindow();
*)[fGxz
\ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
5bb#{?2i //{{AFX_MSG_MAP(CHookApp)
\O*ZW7?TJ // NOTE - the ClassWizard will add and remove mapping macros here.
\J:+Wl.9A // DO NOT EDIT what you see in these blocks of generated code!
$NCvF' //}}AFX_MSG_MAP
bWL!= END_MESSAGE_MAP()
Gza=
0 1F.._5_"] CHookApp::CHookApp()
Rd8mn'A {
:V(C+bm * // TODO: add construction code here,
GUL~k@:_k // Place all significant initialization in InitInstance
i,^-9 }
YusmMsN?
:%sG'_d CHookApp theApp;
x)80:A} LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
5kqI {
{X?Aj >l BOOL bProcessed=FALSE;
Z +/3rd if(HC_ACTION==nCode)
5CnNp?.t^ {
l&\y]ZV={ if((lParam&0xc0000000)==0xc0000000){// Key up
JQb{?C switch(wParam)
N-N]BS6 {
B\D)21Ik}% case VK_MENU:
P^o@x,V!& MaskBits&=~ALTBIT;
>~d'i break;
[vI ;A! case VK_CONTROL:
*v#V%_ o MaskBits&=~CTRLBIT;
)h ,v(Rxa break;
NvzPZ9=@- case VK_SHIFT:
="G2I\ MaskBits&=~SHIFTBIT;
Y4YZM break;
FVNTE+LW default: //judge the key and send message
a2?@OJ break;
;Q3[} ]su }
o5/BE`VD5c for(int index=0;index<MAX_KEY;index++){
V+D <626o if(hCallWnd[index]==NULL)
C}9GrIi continue;
h@JX?LzZS if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
XX-(>B0L {
/IcGJ&; SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
:tbI=NDb bProcessed=TRUE;
yC
?p,Ci, }
7"Nda3 }
eSIG+{;& }
FD!8o else if((lParam&0xc000ffff)==1){ //Key down
#Fo#f<bp switch(wParam)
PcbhylKd {
D,*|:i case VK_MENU:
f5M;q; MaskBits|=ALTBIT;
nN.Gn+Cl break;
)AEtW[~D case VK_CONTROL:
W4.w MaskBits|=CTRLBIT;
4cy,'B break;
byP< !p* case VK_SHIFT:
%Un wh1VG MaskBits|=SHIFTBIT;
bD/ZKvg break;
BT}l" default: //judge the key and send message
tf54EIy5Y break;
|d~'X%b% }
\^pc"?Rc for(int index=0;index<MAX_KEY;index++)
/
j "}e_Q {
mc`Z;D/mt if(hCallWnd[index]==NULL)
JXRU9`3)A continue;
mVS^HQ: if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Yx,E5}- {
FS)#
v SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
T9J&^I bProcessed=TRUE;
&=S:I!9;; }
$;(@0UDE }
]iW:YNvXA }
LRWM}'.s if(!bProcessed){
|Wa.W0A for(int index=0;index<MAX_KEY;index++){
%nUN if(hCallWnd[index]==NULL)
*@^@7`W continue;
}'}n~cA.{ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
|RD)pvVM SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
"uL~D5!f }
vP#*if[V5 }
wjH1Ombt }
7.
$wK. return CallNextHookEx( hHook, nCode, wParam, lParam );
H)S!%(x4 }
$8(QBZq cR!M{U.q BOOL InitHotkey()
a-S
tOO5s {
IS!OO< if(hHook!=NULL){
}:0ru_F)(4 nHookCount++;
p-\->_9)y` return TRUE;
31 <0Nw;l }
f|_\GVW else
F_-xp1| hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
nql9SQ'\\ if(hHook!=NULL)
w
oIZFus nHookCount++;
=Yl ea,S return (hHook!=NULL);
N.q*jY=X| }
;ow)N <Z BOOL UnInit()
d^M*%a z {
\1<|X].jNY if(nHookCount>1){
R{Zd ]HT nHookCount--;
PCL
;Z return TRUE;
}ssja,; }
W 2[]m>; BOOL unhooked = UnhookWindowsHookEx(hHook);
^$%
Sg// if(unhooked==TRUE){
R@pY+d9qp nHookCount=0;
<FU?^*~ hHook=NULL;
k]$oir }
O9>$(`@I return unhooked;
>EFWevT{ }
w1-P6cf ;ltk}hJ] BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
_A!Fp0}` {
Z|x|8 !D BOOL bAdded=FALSE;
&wY$G! P for(int index=0;index<MAX_KEY;index++){
R3a}YwJFXF if(hCallWnd[index]==0){
ZQfPDH= hCallWnd[index]=hWnd;
#O;JV}y HotKey[index]=cKey;
(57!{[J HotKeyMask[index]=cMask;
1,;zX^ bAdded=TRUE;
pw4^E|X KeyCount++;
=+wd"Bu break;
*IWW,@0 }
[(3s5)O }
2yg6hR return bAdded;
$57b.+2n }
_9 '_w& -j]k^ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
x,U_x {
LOi}\O8 BOOL bRemoved=FALSE;
<nqv)g"u0 for(int index=0;index<MAX_KEY;index++){
~I+MuI[ if(hCallWnd[index]==hWnd){
TE+>|}]R if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
G'G8`1Nj hCallWnd[index]=NULL;
aif;h!
?y HotKey[index]=0;
D%yY&q;
HotKeyMask[index]=0;
uz{RV_IX7 bRemoved=TRUE;
7>j~;p{ KeyCount--;
kq5X<'MM9N break;
_7;:*'>a4 }
1
rhZlmf[r }
KB](W }
m?<E >-bI return bRemoved;
/ 'qoKof }
6^'BTd thJ~*
0^ void VerifyWindow()
R'tKJ_VI {
.nrllVG%` for(int i=0;i<MAX_KEY;i++){
eyyME c! if(hCallWnd
!=NULL){ gd*Gn"
if(!IsWindow(hCallWnd)){ *l+Dbm,u
hCallWnd=NULL; l^Rb%?4Z
HotKey=0; ,.W7Z~z
HotKeyMask=0; PY^#hC5:
KeyCount--; -<6?ISF2
} <R /\nY Xz
} bu]"?bc
} [ncK+rGAc
} , [|aWT%9
be,Rj,-
BOOL CHookApp::InitInstance() }<0N)dpT
{ ]oB~8d
AFX_MANAGE_STATE(AfxGetStaticModuleState()); Eu`|8# [ W
hins=AfxGetInstanceHandle(); ]A3
InitHotkey(); rKrHd
return CWinApp::InitInstance(); e(?w h
} c;$4}U4
!=YKfzE
int CHookApp::ExitInstance() _VKI@
{ A#=TR_@:
VerifyWindow(); IA@>'O
UnInit(); XnQR(r)pR2
return CWinApp::ExitInstance(); E&P2E3P
} -d\sKc
i3,IEN
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file #s\@fp7A
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) @b,Az{EH
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ VLez<Id9(
#if _MSC_VER > 1000 sE pI)9
#pragma once qSc-V`*
#endif // _MSC_VER > 1000 SeD}H=,@
^viabkf C
class CCaptureDlg : public CDialog l;lrf3
{ \wK&wRn)
// Construction <&3P\aM>
public: !bE-&c
BOOL bTray; ]4l2jY
BOOL bRegistered; %f;dn<m=c
BOOL RegisterHotkey(); zt(lV
UCHAR cKey; f+h\RE=BGt
UCHAR cMask; : {p'U2
void DeleteIcon(); @NL cO}
void AddIcon(); QqA=QTZ}
UINT nCount; ~3F'X
void SaveBmp(); .[Sis<A]%
CCaptureDlg(CWnd* pParent = NULL); // standard constructor VeYT[Us"
// Dialog Data n)e2?
//{{AFX_DATA(CCaptureDlg) O3} JOv_
enum { IDD = IDD_CAPTURE_DIALOG }; ?=? _32O
CComboBox m_Key; yLnQ9BXB&
BOOL m_bControl; qjB:6Jq4q
BOOL m_bAlt; 4&}%GH>}
BOOL m_bShift; ZL(
j5E
CString m_Path; ]r
Uj<[O
CString m_Number; -S'KxC
//}}AFX_DATA @/z\p7e
// ClassWizard generated virtual function overrides aM}9ZurI
//{{AFX_VIRTUAL(CCaptureDlg) B9maz"lJ
public: [,o:nry'a
virtual BOOL PreTranslateMessage(MSG* pMsg); +\eJxyO
protected: _~<sb,W
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support Z`Y&cK