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:
_=)!xnYf
S{Rh'x\B 一、实现方法
i:R!T, cy9N:MR(c 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:
DwT i_8m; *(>Jd|C #pragma data_seg("shareddata")
IZ|c<#r6 HHOOK hHook =NULL; //钩子句柄
E#8J+7 UINT nHookCount =0; //挂接的程序数目
MyK^i2eD static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
a_xQ~:H static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
M3)v-" static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
6_pDe static int KeyCount =0;
Bfu/9ad static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
rK*hTjVn #pragma data_seg()
J,MT^ B 5ZZd.9ZgM 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。
R
A*(|n> e1:u1(". 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:
Cq
TH!'N 7^`RP e^a+ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
aS3P(s L cKey,UCHAR cMask)
t- !h
X/ {
|Tj`qJGVw BOOL bAdded=FALSE;
:t_}_!~ for(int index=0;index<MAX_KEY;index++){
YmdsI+DbIu if(hCallWnd[index]==0){
IJ+O),' hCallWnd[index]=hWnd;
o:p{^D@#k HotKey[index]=cKey;
\CP*i_:" HotKeyMask[index]=cMask;
%?U"[F1 bAdded=TRUE;
9)8*FahW KeyCount++;
Iwnj'R7: break;
*'kC8ZR5 }
-i| /JH }
{LjK_J' return bAdded;
O8!!UA8V }
=?y^O0v //删除热键
8 ))I$+ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
h #$_<U {
[YL sEo= BOOL bRemoved=FALSE;
yYVW"m for(int index=0;index<MAX_KEY;index++){
54, Ju'r if(hCallWnd[index]==hWnd){
! hOOpZf7 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
"j*fVn hCallWnd[index]=NULL;
D/+@d:- G HotKey[index]=0;
%Z-Tb OX HotKeyMask[index]=0;
UMnR=~. bRemoved=TRUE;
.H*? '* KeyCount--;
853]CK< break;
MVu[gB }
$Qx(aWE0 }
C.B8 J"T- }
6%Cna0x:& return bRemoved;
LIm$Wl1U }
mP`,I"u T%z!+/=&^ gK] T} DLL中的钩子函数如下:
gu~-} [qc6Q: LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
2/a04qA# {
z.Ve#~\ BOOL bProcessed=FALSE;
)%-\hl] if(HC_ACTION==nCode)
-NI@xJO4(; {
Au\=ypK if((lParam&0xc0000000)==0xc0000000){// 有键松开
tPMgZ switch(wParam)
Lt#:R\;& {
:Kt mSY case VK_MENU:
w|3fioLs MaskBits&=~ALTBIT;
3 8ls 4v3 break;
]c~ rPi case VK_CONTROL:
\f<thd*bC MaskBits&=~CTRLBIT;
`rRg(fCN!M break;
$$)<(MP3 case VK_SHIFT:
QvyUd%e'5A MaskBits&=~SHIFTBIT;
>u%[J!Y;; break;
:W1tIB default: //judge the key and send message
Qcy+ {j] break;
iI/'!85 }
'ra_Zg[j for(int index=0;index<MAX_KEY;index++){
s^x ,S if(hCallWnd[index]==NULL)
&Funao> continue;
A`mf 8'nTG if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
9EY_R&Yq% {
lj% ;d' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
>goAf`sqo bProcessed=TRUE;
%%H. &*i, }
zv3<i ( }
T<_1|eH }
8~XI7g'5x else if((lParam&0xc000ffff)==1){ //有键按下
A&@jA5Jb switch(wParam)
RdpQJ)3F {
( Nve5 case VK_MENU:
#v]aT
]} MaskBits|=ALTBIT;
,_7tRkn break;
+[go7A$5 case VK_CONTROL:
U#^:f7-$. MaskBits|=CTRLBIT;
{ /Q? break;
Z6HkQ=A64 case VK_SHIFT:
" kJWWR MaskBits|=SHIFTBIT;
x[h<3V" break;
s(DaPhL6Qm default: //judge the key and send message
SGT-B. break;
bKbpI>;[ }
r E*u for(int index=0;index<MAX_KEY;index++){
4~J1pcBno% if(hCallWnd[index]==NULL)
d~oWu [F* continue;
$1`t+0^k if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
>w2WyYJYH {
XdXS^QA.s SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
J}` $WL: bProcessed=TRUE;
jjlCi<9CQ^ }
GA@Q:n8UuR }
/[|md0, }
p!5JO4F$ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
{?M*ZRO' for(int index=0;index<MAX_KEY;index++){
yeh adm\ if(hCallWnd[index]==NULL)
Z`Eb
L continue;
4OgGZ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
V$]a&wM<5 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
s)ajy^6'M //lParam的意义可看MSDN中WM_KEYDOWN部分
~k_zMU-1 }
74N\G1 }
rsj}hS$ }
MrjB[3Td return CallNextHookEx( hHook, nCode, wParam, lParam );
i!-sbwd7 }
[==Z1Q;= wtick~) 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:
u~Cqdr5
\l D,R2wNF BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
aNEy1-/(\ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Q`fA)6U {Q3#]Vu 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:
{Ao^3vB K>~cY%3^i LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
N=Yi:+ {
m!>'}z if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
#6Ph"\G/ {
KTREOOu .t //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
y#W8] <dS" SaveBmp();
-5B([jHgR return FALSE;
ZuV }
fmyS#
6" …… //其它处理及默认处理
f3&//h8 }
Sk%|-T(d$ 87*[o ^IZ0M1&W; 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。
*wx^mB9 _Dt TG<E 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。
q.tL' /1GZN *I 二、编程步骤
`Hu;Gdj= r+yLK(<zp 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";
wBGxJ\+M FNO
lR>0e 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
{u][q
&n aB_z4dqwU 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;
CK#PxT?" 9e6{( 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;
0`=?ig_ ZU6a 5、 添加代码,编译运行程序。
OOwJ3I >]> \Ki#"%S 三、程序代码
3xY]Lqwv
/PS]AM ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
)Jn80~U|1 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
]d(}b>gR~( #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
GT0'bge #if _MSC_VER > 1000
MeS$+9jV( #pragma once
Hn.UJ4V #endif // _MSC_VER > 1000
.;s4T?j@w #ifndef __AFXWIN_H__
6U]7V #error include 'stdafx.h' before including this file for PCH
;c}];ZU3G #endif
3 g&mND #include "resource.h" // main symbols
wkw/AZ{27 class CHookApp : public CWinApp
exvsf| {
^5F/=TtE G public:
J ASn\z CHookApp();
@e/dQ:Fb // Overrides
Rl8-a8j$f. // ClassWizard generated virtual function overrides
:r=_\? //{{AFX_VIRTUAL(CHookApp)
WDR!e2G public:
N<WFe5 virtual BOOL InitInstance();
r8$TT\?~ virtual int ExitInstance();
+UtK2<^:o //}}AFX_VIRTUAL
,j<"~"]
= //{{AFX_MSG(CHookApp)
J>Ha$1}u/ // NOTE - the ClassWizard will add and remove member functions here.
<NO~TBHF // DO NOT EDIT what you see in these blocks of generated code !
p
IToy;] //}}AFX_MSG
Y@eUvz DECLARE_MESSAGE_MAP()
K<(RVh };
WBIS LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
N0f}q1S<-A BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
g<Xwk2_=g BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
~sD'pS BOOL InitHotkey();
DQ$/0bq BOOL UnInit();
<}%*4mv #endif
O&uOm:/( mLO6`]p{H //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
I6_+3}Hm{ #include "stdafx.h"
*yx:nwmo #include "hook.h"
sBMHf9u #include <windowsx.h>
+Gko[< #ifdef _DEBUG
fz*6 B NJ #define new DEBUG_NEW
hv6>3gbr #undef THIS_FILE
TEtZPGFl static char THIS_FILE[] = __FILE__;
VTU-'q #endif
>8so'7( #define MAX_KEY 100
F(9T;F #define CTRLBIT 0x04
[sBD|P;M #define ALTBIT 0x02
l3,|r QD #define SHIFTBIT 0x01
aryr #pragma data_seg("shareddata")
eJ'ojc3 HHOOK hHook =NULL;
z; +x`i. UINT nHookCount =0;
dj#<,e\ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
$si2H8 static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
gd*\,P static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
})Jp5vv static int KeyCount =0;
F`l1I=; static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
Kfh"XpWc$ #pragma data_seg()
BshS@"8r HINSTANCE hins;
e=U7w7(s9 void VerifyWindow();
#X+) BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
*7ox_ R@ //{{AFX_MSG_MAP(CHookApp)
fXN;N&I // NOTE - the ClassWizard will add and remove mapping macros here.
YG_3@`-< // DO NOT EDIT what you see in these blocks of generated code!
P7n~Ui~U //}}AFX_MSG_MAP
d 9|u~3 END_MESSAGE_MAP()
BmZd,}{ ji "*=i CHookApp::CHookApp()
+q1@,LxN {
UX6-{
RP // TODO: add construction code here,
}.#C9<"} // Place all significant initialization in InitInstance
WE3l*7<@ }
vCJjZ%eO%D ^U52
*6 CHookApp theApp;
U;_;_ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
_$\T;m>'A {
Gh j[nsoC~ BOOL bProcessed=FALSE;
B,676~I if(HC_ACTION==nCode)
$ysC)5q. {
)gE:@3 if((lParam&0xc0000000)==0xc0000000){// Key up
9T\:ID=h switch(wParam)
?/;<32cE, {
fQ<V_loP.@ case VK_MENU:
|
.PLfc; MaskBits&=~ALTBIT;
LWY`J0/ break;
l)?c3 case VK_CONTROL:
'+$2<Ys MaskBits&=~CTRLBIT;
%FwLFo^v break;
?wmr~j case VK_SHIFT:
^T^fowt=r MaskBits&=~SHIFTBIT;
A2xORG&FD break;
DY1o!thz) default: //judge the key and send message
PS>k67sI break;
&.d~
M1Mz }
.; :[sv) for(int index=0;index<MAX_KEY;index++){
[Ga9^e$Zv if(hCallWnd[index]==NULL)
il*bsnwpZv continue;
&AW?!rH if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
?R";EnD {
2lQ'rnqS) SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
]R0^
}sI bProcessed=TRUE;
zD?<m
J` }
%hY+%^k. }
!x>P]j7A}Y }
=_,w< else if((lParam&0xc000ffff)==1){ //Key down
Nj?,'?'O} switch(wParam)
U|,VH-# {
)5hS;u&b case VK_MENU:
% nJ'r?+h MaskBits|=ALTBIT;
"}EydG"= break;
y>|7'M*+ case VK_CONTROL:
9^`G `D MaskBits|=CTRLBIT;
* ,,D%L break;
`6UW?1_Z5 case VK_SHIFT:
zL1H[}[z+ MaskBits|=SHIFTBIT;
w+PbT6; break;
Uc\\..Cf default: //judge the key and send message
PZQ}G*p3 break;
o: TO[ }
R(3V !ph for(int index=0;index<MAX_KEY;index++)
Si!W@Jm {
je.mX /Lpj if(hCallWnd[index]==NULL)
^oM*f{9 continue;
9;kWuP>k4u if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
}*;Hhbox {
4u A;--j SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
IeE+h-3p bProcessed=TRUE;
&%rXRP }
v@[MX- ,8 }
DqbN=[!X~n }
u[y>DPPx if(!bProcessed){
ACc.&,!IZ for(int index=0;index<MAX_KEY;index++){
cvi+AZ= if(hCallWnd[index]==NULL)
_<&IpT{w+ continue;
dX` _Y if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
g;Bq#/w SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Jt@7y"< }
b>?X8)f2e }
"C%;9_ig$ }
yin"+&<T return CallNextHookEx( hHook, nCode, wParam, lParam );
$U3s:VQ ' }
IKH#[jW'IB >i-cR4=LL{ BOOL InitHotkey()
-TSn_XE {
,@8>=rT if(hHook!=NULL){
ZI-)' nHookCount++;
%#Fd0L return TRUE;
BB>3Kj:| }
Jcy else
h{VCx#!] hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
o0_RU<bWN if(hHook!=NULL)
%
=br-c nHookCount++;
26&^n
Uy return (hHook!=NULL);
pu=Q;E_f[ }
+(QGlRd BOOL UnInit()
qJKD|=_ {
[_#9PH33 if(nHookCount>1){
Ay22-/C|@ nHookCount--;
L00,{g6wqb return TRUE;
z{7&= $ }
1B}6 zJ BOOL unhooked = UnhookWindowsHookEx(hHook);
#92:h6 if(unhooked==TRUE){
2(Vm0E nHookCount=0;
Gmf.lHr$% hHook=NULL;
1.]#FJe }
g< M\zD return unhooked;
Nj@k|_1 }
:OUNZDL ubju uha" BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
AM#VRRTU {
=(3Qbb1i BOOL bAdded=FALSE;
Y, )'0O for(int index=0;index<MAX_KEY;index++){
|.0/~Xy- if(hCallWnd[index]==0){
%e+hM $Q hCallWnd[index]=hWnd;
&Ru|L.G` HotKey[index]=cKey;
SL?
!
RQ HotKeyMask[index]=cMask;
TwqyQ49 bAdded=TRUE;
XTUxMdN KeyCount++;
z
AacX@ break;
6Y>MW 4q }
pej/9{*xg( }
;oH17 return bAdded;
6@t4pML }
. Zrt/; \SHYwD}*Pr BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
)!SV V ~y {
|<96H8 BOOL bRemoved=FALSE;
|CexP^;!U for(int index=0;index<MAX_KEY;index++){
>JkQU e if(hCallWnd[index]==hWnd){
{OL*E0 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
eu@-v"=w hCallWnd[index]=NULL;
tx;MH5s/V HotKey[index]=0;
v7&e,:r2E@ HotKeyMask[index]=0;
+y! dU{L^ bRemoved=TRUE;
FVW<F(g` KeyCount--;
UeIu
-[R break;
s4<[f%^ }
R] tHd=kf }
2`Ub;Nn29 }
YAv-5 return bRemoved;
,B(UkPGT }
O8(;=exA W$O^IC void VerifyWindow()
pk%I98! Jy {
: ~"^st_[! for(int i=0;i<MAX_KEY;i++){
8xJdK' if(hCallWnd
!=NULL){ }{[H@uhjH
if(!IsWindow(hCallWnd)){ %6j|/|#]
hCallWnd=NULL; DmEmv/N=
HotKey=0; bo '
HotKeyMask=0; ^n!{ vHz
KeyCount--; Q.7Rv
XNw8
} GMU.Kt
} Q:&,8h[
} .;ml[DXH
} "#z4
Po'yr] pr
BOOL CHookApp::InitInstance() Z#BwJHh
{ 7}(wEC
AFX_MANAGE_STATE(AfxGetStaticModuleState()); kbJ/7
hins=AfxGetInstanceHandle(); A8&yB;T$y
InitHotkey(); I~\j%zD
return CWinApp::InitInstance(); QMea2q|3$
} `e .;P
U>7"BpC
int CHookApp::ExitInstance() oe_l:Y%
{ B;XFPQ#b
VerifyWindow(); :BKY#uH~
UnInit(); E#JDbV1AC
return CWinApp::ExitInstance(); ;ZPAnd:pb
} }@=m[Zx#
b)J(0,9`G"
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file 7r 07N'
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) aF2eGh
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ m663%b(5>
#if _MSC_VER > 1000 >DVjO9Kf
#pragma once ${0+LhST
#endif // _MSC_VER > 1000 v^2K=f[nE
o)F^0t
class CCaptureDlg : public CDialog !31v@v:)
{ ke_Dd?
// Construction |B<+Y<)f^
public: jG)fM?
BOOL bTray; }C!N$8d,
BOOL bRegistered; ?&EPZq