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:
Zo}y(N1K}
_kdL'x 一、实现方法
! {82D[5 +dPL>R 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:
>^OC{~Az R@*O!bD #pragma data_seg("shareddata")
"&/]@)TPz HHOOK hHook =NULL; //钩子句柄
Qf|U0 UINT nHookCount =0; //挂接的程序数目
8:o<ry static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
b:(- static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
+hRmO static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
4:sjH.u< static int KeyCount =0;
N,J9Wu ZJ\ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
1Fe^Qb5G #pragma data_seg()
NB7Y{)
w .,i(2^ 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。
*1'`"D~ QnI.zq
V 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:
>?]_<: `Bw9O%]-S BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
enTW0U} cKey,UCHAR cMask)
5PIZh< {
T?p`) BOOL bAdded=FALSE;
yE\wj for(int index=0;index<MAX_KEY;index++){
j6,ZEm if(hCallWnd[index]==0){
IF +i3#$ hCallWnd[index]=hWnd;
W{5:'9, HotKey[index]=cKey;
@<@SMK) HotKeyMask[index]=cMask;
#-Z8Z
i"44 bAdded=TRUE;
?,=f\Fz! KeyCount++;
ycJg%]F*5 break;
Nk;iiz+_p }
Y2R \]FrT }
tURc bwV return bAdded;
Fa epDjY8 }
~RBrSu) //删除热键
IhiGP
{ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
3pXLSdxB {
#Ch;0UvFF BOOL bRemoved=FALSE;
}6-ZE9H-v for(int index=0;index<MAX_KEY;index++){
ow/57P if(hCallWnd[index]==hWnd){
\#rO!z
d if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ya
-i^i\ hCallWnd[index]=NULL;
*<'M!iRC HotKey[index]=0;
o]LRzI HotKeyMask[index]=0;
P(SZ68 bRemoved=TRUE;
"{E qhR~ KeyCount--;
7$k8%lI;> break;
Pz_NDI }
a{!r`>I\f }
3SBZ> }
B(DrY1ztj return bRemoved;
;XC@=RpX }
U{ ;l0 2S 46h@j>/K _Hd{sd#xX1 DLL中的钩子函数如下:
vU*x2fVb} W"Jn(:& LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
8yWoPm<A {
%>WbmpIyc BOOL bProcessed=FALSE;
e9^2,:wLB if(HC_ACTION==nCode)
1P]de'-`j {
J.RAmU < if((lParam&0xc0000000)==0xc0000000){// 有键松开
nd{R
9B switch(wParam)
;$BdP7i: {
DXQi-+? case VK_MENU:
%gcc
y| MaskBits&=~ALTBIT;
1#
t6`N]?V break;
L fl-!1 case VK_CONTROL:
n^hocGH* MaskBits&=~CTRLBIT;
quo^fqS&a break;
x3e]d$ case VK_SHIFT:
=/+#PVO MaskBits&=~SHIFTBIT;
gcJF`H/iNK break;
-@IL"U6 default: //judge the key and send message
eX2<}'W< break;
d'l$$%zJ }
R<zG^m for(int index=0;index<MAX_KEY;index++){
CiL94Nkd9 if(hCallWnd[index]==NULL)
!RlC~^
- continue;
(D{Ys'{q if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
5M23/=
N {
0+b0< SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
m_!U}! bProcessed=TRUE;
NNa1EXZ[ }
l
SkEuN }
3^.8.q(6 }
hxC!+ArVe else if((lParam&0xc000ffff)==1){ //有键按下
M0-,M/]l switch(wParam)
(\dK4JJ {
XNH4==4 case VK_MENU:
>!9h6BoGV MaskBits|=ALTBIT;
sFb4` break;
3]n0 &MZAR case VK_CONTROL:
Jbp5'e
_ MaskBits|=CTRLBIT;
E=/[s]@5 break;
y~F<9;$= case VK_SHIFT:
^GYq#q9Q MaskBits|=SHIFTBIT;
j5%qv(w break;
j1$<] f default: //judge the key and send message
WA
LGIW break;
{@r*+~C3 }
agd)ag4"[u for(int index=0;index<MAX_KEY;index++){
PM4>ThQ if(hCallWnd[index]==NULL)
^p_u.P continue;
HPa|uDVv if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
9DEh*%q {
.yVnw^gu SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
2W3W/> 2h bProcessed=TRUE;
dALK0U }
B;-2$
77 }
daOS8_py }
(BERY if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
o@dy:AR for(int index=0;index<MAX_KEY;index++){
5a(<%Q
<" if(hCallWnd[index]==NULL)
wq4nMY:# continue;
'1]7zWbW if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
_2jw,WKr SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
D&*LBQ/K //lParam的意义可看MSDN中WM_KEYDOWN部分
>;i\v7 }
2z983^ }
4YJ=q% G }
jNy?[
) return CallNextHookEx( hHook, nCode, wParam, lParam );
ma9ADFFT }
"E>t,
D ):bu;3E 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:
, deUsc FD6v/Y BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
q{X T BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
p(7QAd4 VjTe4$ * 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:
8Z:Ezg3^ -3mgza LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
rR!U; {
@8"18HEp# if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
Bp0bY9xLg_ {
k!doIMj //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
3cu9[~K SaveBmp();
PV,"-Nv, return FALSE;
6s,2NeVWa }
)
p^ …… //其它处理及默认处理
Z5>V{o }
j,t~ Lp~^*j( xeB4r/6 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。
Igjr~@# Ky&KF0 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。
>I-g[* >38
Lt\ 二、编程步骤
G&o64W;-s z{6YC~ 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";
y~p4">] k_Tswf3 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
\/,g VT BPWnck=% 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;
d_iY&-gq/ baIbf@t/ 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;
l7Lj[d<n a`38db(z 5、 添加代码,编译运行程序。
aFG3tuaKrQ $WNG07]tU 三、程序代码
q2!'==h2i .&chdVcxyS ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
kV1vb #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
A7(M,4`6 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
QUPf*3Oy #if _MSC_VER > 1000
C<t RU5| #pragma once
Xb+3Xn0}&8 #endif // _MSC_VER > 1000
ja75c~RUw #ifndef __AFXWIN_H__
_:5=|2-E #error include 'stdafx.h' before including this file for PCH
6To:T[ z# #endif
DVzssPg #include "resource.h" // main symbols
`Z8^+AMc class CHookApp : public CWinApp
@,YlmX} {
fN0bIE
Y public:
H56
^n<tg CHookApp();
Vr\Q`H. // Overrides
M@~o6 ^ // ClassWizard generated virtual function overrides
7O461$4v //{{AFX_VIRTUAL(CHookApp)
=z-5 public:
c
`ud;lI virtual BOOL InitInstance();
eKJ:?Lxv; virtual int ExitInstance();
M,JA;a, _ //}}AFX_VIRTUAL
!a4cjc( //{{AFX_MSG(CHookApp)
gV.f*E1C // NOTE - the ClassWizard will add and remove member functions here.
qwP $~Bj // DO NOT EDIT what you see in these blocks of generated code !
&>V/X{>$`K //}}AFX_MSG
8{@`kyy| DECLARE_MESSAGE_MAP()
/u?9S/ };
*]'qLL7d LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
F(E<,l2[ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
(!ZV9S BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
*N'hA5.z BOOL InitHotkey();
.ujj:> BOOL UnInit();
/4H[4m]I #endif
6s5b$x e2Ww0IK!E //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
(s Jq;Z #include "stdafx.h"
k)i"tpw #include "hook.h"
hU)'OKe #include <windowsx.h>
R|H[lbw #ifdef _DEBUG
=
uk`pj[l #define new DEBUG_NEW
Me<du&
T #undef THIS_FILE
\KNdZC?V2 static char THIS_FILE[] = __FILE__;
9iK&f\#5H #endif
X
[!X>w&z| #define MAX_KEY 100
+]_nbWL(% #define CTRLBIT 0x04
u x#.:C| #define ALTBIT 0x02
pEkOSG #define SHIFTBIT 0x01
E+Im~=m$ #pragma data_seg("shareddata")
_lNC<7+#h HHOOK hHook =NULL;
w`0)x5
TGR UINT nHookCount =0;
]DU61Z"v?b static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
v}f&q! static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
)ZN(2z static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
bk0Y static int KeyCount =0;
IyT?-R static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
$mD>rx #pragma data_seg()
ret0z| HINSTANCE hins;
9,w}Xe=C void VerifyWindow();
H):-!?: BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
1N>6rN //{{AFX_MSG_MAP(CHookApp)
1GUqT 9) // NOTE - the ClassWizard will add and remove mapping macros here.
L!&$c&=xf // DO NOT EDIT what you see in these blocks of generated code!
D-~G|8g //}}AFX_MSG_MAP
-$OD }5ku# END_MESSAGE_MAP()
K Ka c6Zj ^A- sS~w CHookApp::CHookApp()
:;q>31:h {
&q"'_4 // TODO: add construction code here,
R|$[U // Place all significant initialization in InitInstance
xHm/^C&px }
Ou? r {$(b 2q/nAQ+ CHookApp theApp;
;C+cE# LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
e/ WBgiLw {
V8\$`NEP BOOL bProcessed=FALSE;
m:b^,2"g if(HC_ACTION==nCode)
@c0n2 Xcr {
(lieiye^ if((lParam&0xc0000000)==0xc0000000){// Key up
H/pcXj switch(wParam)
6hLNJ {
C(xqvK~p case VK_MENU:
=zz+<!! MaskBits&=~ALTBIT;
70duk:Ri0 break;
qP qy4V.; case VK_CONTROL:
Uld_X\;Q4 MaskBits&=~CTRLBIT;
9e-*JYF]C break;
m';#R9\Fz case VK_SHIFT:
EZ..^M3 MaskBits&=~SHIFTBIT;
L#`7 FaM? break;
<sO?ev[ default: //judge the key and send message
>6XDX=JVI break;
c%jsu" }
bd} r#^'K for(int index=0;index<MAX_KEY;index++){
{3.*7gnY\L if(hCallWnd[index]==NULL)
s c5\( b continue;
tSI& "- if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
v'h3CaA9j {
W^003*m~~K SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Q^[e/U, bProcessed=TRUE;
p}96uaC1 }
1!X1wCT }
wH+FFXGJs }
4=~ 9v else if((lParam&0xc000ffff)==1){ //Key down
>'eB2 switch(wParam)
ZGA)r0]
P` {
:jBZK=3F> case VK_MENU:
T!Xm")d MaskBits|=ALTBIT;
1]_?$)$T break;
1V-=$Q3
V7 case VK_CONTROL:
C2CYIok$& MaskBits|=CTRLBIT;
k& WS$R?u break;
]cn/(U` case VK_SHIFT:
Fq vQk MaskBits|=SHIFTBIT;
||yXp2 break;
R:]/{b4Uq default: //judge the key and send message
*Kp}B}}J break;
g[m3IJzq }
-,FK{[h]ka for(int index=0;index<MAX_KEY;index++)
z Z@L4ZT {
:!(YEF#} if(hCallWnd[index]==NULL)
dVPq%[J2 continue;
lr-12-D%- if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
2T//%ys= {
|sA4:Aq SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
5ze`IY bProcessed=TRUE;
fEHh]%GT` }
&7$,<9. }
D/gd }
g&{gD^9)4 if(!bProcessed){
)?F$-~7 for(int index=0;index<MAX_KEY;index++){
8$2l^ if(hCallWnd[index]==NULL)
kX@bv"i continue;
K~`n}_: if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
UedvA9$&; SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
/!^L69um }
<Gn8B^~$ }
4kWg>F3 }
A
Z4|&iT return CallNextHookEx( hHook, nCode, wParam, lParam );
BO?mQu~ }
-
P\S>G. KYnW7|* BOOL InitHotkey()
Sg/:n,68 {
>{j,+$%kp if(hHook!=NULL){
=$^Wkau nHookCount++;
eFt\D\XOW return TRUE;
Z[a O_6L }
2=igS#h else
`%FIgE^ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
}V\P,ck if(hHook!=NULL)
di8W2cwz nHookCount++;
]cx" return (hHook!=NULL);
vh<]aiY }
//#xK D BOOL UnInit()
fKPiRlLS {
I(z>)S'7r if(nHookCount>1){
9=Y,["br$_ nHookCount--;
A Oby*c return TRUE;
A8\U
CG }
B@ZqJw9J[ BOOL unhooked = UnhookWindowsHookEx(hHook);
@o}1n?w if(unhooked==TRUE){
jf$JaY nHookCount=0;
Q
mb[ e> hHook=NULL;
fQ=&@ >e }
Am>_4 return unhooked;
s$f+/Hs }
4y|xUO: 4(` 2# BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
cxtLy&C {
"WF(
6z# BOOL bAdded=FALSE;
>{O[t2& for(int index=0;index<MAX_KEY;index++){
e#l*/G*, if(hCallWnd[index]==0){
c'4>D,?1 hCallWnd[index]=hWnd;
JK@izI HotKey[index]=cKey;
|HaU3E*R HotKeyMask[index]=cMask;
[ea6dv4p bAdded=TRUE;
u}JQTro KeyCount++;
mr:kn0 break;
2uvQf&, }
9F2P(aS }
z5x,fQw6O return bAdded;
X@6zI-Y% }
X% Spv/8{ ^tm++ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
B'G*y2UnG {
Fy}MXe"f BOOL bRemoved=FALSE;
xT_fr,P for(int index=0;index<MAX_KEY;index++){
.yctE:n if(hCallWnd[index]==hWnd){
(t]lP/
if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
E[ )7tr hCallWnd[index]=NULL;
j[$B\H HotKey[index]=0;
>u BV HotKeyMask[index]=0;
|y{;|K bRemoved=TRUE;
J{nyo1A KeyCount--;
Nb^zkg break;
/3)YWFZZc }
A2g"=x[1@K }
}XfS#Xr1aV }
o9U0kI=W return bRemoved;
5]4<!m }
s`8M%ZLu OYqYI!N/ void VerifyWindow()
L Q I: ]d {
)
xfc-Q for(int i=0;i<MAX_KEY;i++){
TEaD-mY3 if(hCallWnd
!=NULL){ -4*'WzWr
if(!IsWindow(hCallWnd)){ s=^r/Sz902
hCallWnd=NULL; u^#4G7<
HotKey=0; l}2%?d
HotKeyMask=0; %\(y8QV
KeyCount--; {Y3_I\H8{
} &%f ]-=~
} p|bc=`TD
} ,<uiitOo
} l5\B2 +}7
nLFx/5sL
BOOL CHookApp::InitInstance() H6%!v1 u
{ .oi}SG
AFX_MANAGE_STATE(AfxGetStaticModuleState()); T3u5al
hins=AfxGetInstanceHandle(); j61BP8E
InitHotkey(); M`9orq<
return CWinApp::InitInstance(); >D`fp
} "Cyo<|
E6k?+i
w
int CHookApp::ExitInstance() dI#8CO
{ M5cOz|j/*R
VerifyWindow(); `_ J^g&y~
UnInit(); b2/N H1A
return CWinApp::ExitInstance(); I{?E /Sc
} 7"a`-]Ap
APHtJoS
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file p:[`%<j0
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) g:.,}L
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ 1WUFk ?p
#if _MSC_VER > 1000 j,|1y5f
#pragma once p0[,$$pM
#endif // _MSC_VER > 1000 |"Xi%CQ2
zJG x5JC
class CCaptureDlg : public CDialog .WL\:{G8;
{ =BqaGXr
// Construction 5I8FD".i
public: X YNUss
BOOL bTray; |g?/~%7
BOOL bRegistered; O, ``\(P
BOOL RegisterHotkey(); )5GdvqA
UCHAR cKey; hSx+{4PZ
UCHAR cMask; $+lz<~R
void DeleteIcon(); 68'-1}
void AddIcon(); lry&)G=5
UINT nCount; D_yY0rRM
void SaveBmp(); }l]3m=)
CCaptureDlg(CWnd* pParent = NULL); // standard constructor pU:C=hq4
// Dialog Data x;ICV%g/
//{{AFX_DATA(CCaptureDlg) A1k&`
|k
enum { IDD = IDD_CAPTURE_DIALOG }; PNxVW
CComboBox m_Key; 0XQ".:+h
BOOL m_bControl; I9*BENkR
BOOL m_bAlt; s_GK;;
BOOL m_bShift; BuEQ^[Ex
CString m_Path; v'
9( et
CString m_Number; c5=v`hv
//}}AFX_DATA aCUV[CPw
// ClassWizard generated virtual function overrides /,rF$5G,
//{{AFX_VIRTUAL(CCaptureDlg) #5ohmp,u
public: VJ6>3
virtual BOOL PreTranslateMessage(MSG* pMsg); 8H3!; ]
protected: q5I4'6NF
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support oxCs*
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); +QXYU8bYZ
//}}AFX_VIRTUAL uwH)/BW)[
// Implementation EMW4<