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:
3?x}48
dfR?O#JPU 一、实现方法
na`8ulN_ ] vQU(@+I 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:
#I-qL/Lm _|C T|q #pragma data_seg("shareddata")
[ApAd HHOOK hHook =NULL; //钩子句柄
knABlU UINT nHookCount =0; //挂接的程序数目
W5U;{5 static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
0ZJN<AzbA static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
3FQXp static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
+rOfQ'lQ static int KeyCount =0;
/8[T2Z! static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
q +*>T=k #pragma data_seg()
Sd?+j;/" IuOQX} 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。
}Zp5d7(@w |n~Vpy 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:
FX&)~) wpepi8w, BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
FZ@8&T
cKey,UCHAR cMask)
c]3^2Ag, {
g6!#n BOOL bAdded=FALSE;
jx-8%dxtZ for(int index=0;index<MAX_KEY;index++){
oh%/\Xu if(hCallWnd[index]==0){
V?C_PMa hCallWnd[index]=hWnd;
q,fk@GI'2 HotKey[index]=cKey;
mP+rPDGp HotKeyMask[index]=cMask;
0qk.NPMB0 bAdded=TRUE;
ghVxcK KeyCount++;
^#,cWG}z break;
O/{W:hJjd }
SX6P>:` }
bl-t>aO*.V return bAdded;
c[E>2P2-_ }
r/BiR0$E //删除热键
!|;w(/ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Jm{~H% {
cwKOE?! BOOL bRemoved=FALSE;
J6*B=PX=( for(int index=0;index<MAX_KEY;index++){
CJ
9tO#R if(hCallWnd[index]==hWnd){
jHWJpm( if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
G##^xFx hCallWnd[index]=NULL;
C@q&0\HN HotKey[index]=0;
,O}2LaK.O HotKeyMask[index]=0;
"G m:M bRemoved=TRUE;
$[-{Mm KeyCount--;
4,g3 c break;
D:Y`{ { }
9,;+B8-A }
)gq( }
^Wz3 q-^ return bRemoved;
J"dp?i }
bUi@4S Q|W!m0XO 59I} DLL中的钩子函数如下:
Y)X58_En 3tTz$$-# LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
j']Q-s(s {
\w=7L-
8 BOOL bProcessed=FALSE;
1yIo'i1 if(HC_ACTION==nCode)
K-}'Fiq {
,As78^E{ if((lParam&0xc0000000)==0xc0000000){// 有键松开
iAlFgOk' switch(wParam)
"@[xo7T {
'D4KaM.d case VK_MENU:
YMx
zj MaskBits&=~ALTBIT;
Z0 e+CEzq break;
5}4MXI4 case VK_CONTROL:
IBzHXa>75 MaskBits&=~CTRLBIT;
zA/W+j$: break;
u?f3&pA case VK_SHIFT:
_u :4y4} MaskBits&=~SHIFTBIT;
rS
4'@a break;
'c<@SVF{Zz default: //judge the key and send message
:l>T~&/98 break;
oLn| UWe_ }
F*d{< for(int index=0;index<MAX_KEY;index++){
6zLz<p? if(hCallWnd[index]==NULL)
G\H@lFh continue;
'Sc3~lm(dH if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
x./jTebeO {
Sg<''pUh SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
V_(?mC bProcessed=TRUE;
}#
-N7=h }
'eo2a&S2D }
79%${ajSI }
b@f.Kd7I else if((lParam&0xc000ffff)==1){ //有键按下
5hp b=2 switch(wParam)
"7)F";_(^ {
C({L4O#?o case VK_MENU:
m`9)DsR
N MaskBits|=ALTBIT;
/:e|B;P`k break;
AX1'.
case VK_CONTROL:
y Ht63z8' MaskBits|=CTRLBIT;
DI}h?Uf , break;
:7Vm]xd}do case VK_SHIFT:
X5U!25d] MaskBits|=SHIFTBIT;
KX<RD|= break;
igz:ek` default: //judge the key and send message
u 3,b,p break;
fV}\ }
aXC`yQ? for(int index=0;index<MAX_KEY;index++){
&r<<4J(t if(hCallWnd[index]==NULL)
?EX'j
> continue;
^s5.jlZr@ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
g\(7z
P {
$zmES tcm SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
il-&d]AP bProcessed=TRUE;
5[gkGKkf_ }
Ya9uu@F }
Zc9
n0t[ }
u khI#:[ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
F'j:\F6C; for(int index=0;index<MAX_KEY;index++){
~hvhT}lE if(hCallWnd[index]==NULL)
DR0W)K
^ continue;
WejY
b;KS if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
?|hzAF"U SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
,+X8?9v //lParam的意义可看MSDN中WM_KEYDOWN部分
QHs]~Ja }
y
ph }
_~cmR< }
Y*}Sq|y return CallNextHookEx( hHook, nCode, wParam, lParam );
A:NY:#uC }
huTJ
a2 7>ODaj
抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
Pdn.c1[-a 5;^8wh( BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
|M
K-~ep BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
*Cb(4h- ./g0T{& 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
UJm`GO W"Rii]GK" LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
,5\n%J: {
r=w%"3vb^ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
Sc0ZT/Lm {
isd[l-wAmf //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
Ci*5E$+\ SaveBmp();
rb_G0/R return FALSE;
ji8Rd"S }
xxiLi46/ …… //其它处理及默认处理
y1'/@A1 }
>'T%=50YH Z~nl{P# /.?\P#9) 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。
9qW,I|G zV&3l9?U 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。
)b7mzDp( 9BY b{<0tS 二、编程步骤
~8X'p6 }"8_$VDcz 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";
0I _;?i `Q8 D[ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
7/1S5yUr| .Sn1YAhE 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;
z%KChU MQ+ek4 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;
Xm4wuX"e= 96.Wfx 5、 添加代码,编译运行程序。
lV
9q;!/1 QE gv,J{ 三、程序代码
,J^Op
4{?x(~ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
; M(}fV] #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
OS
6 )` #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
op*+fJHD #if _MSC_VER > 1000
c`.:"i"k3 #pragma once
C;5}/J^E #endif // _MSC_VER > 1000
U)!AH^{32 #ifndef __AFXWIN_H__
W% [5~N #error include 'stdafx.h' before including this file for PCH
ts]7 + 6V #endif
uS'ji
k} #include "resource.h" // main symbols
39j d}]e class CHookApp : public CWinApp
=<05PB {
"Pc,+>vh public:
Vk (bU=w CHookApp();
R}>Do=hAO // Overrides
a}K+w7VY\ // ClassWizard generated virtual function overrides
nf4P2<L! //{{AFX_VIRTUAL(CHookApp)
="DgrH public:
Em,!=v(* virtual BOOL InitInstance();
DX";v
J virtual int ExitInstance();
oc(bcU //}}AFX_VIRTUAL
[f0HUbPX //{{AFX_MSG(CHookApp)
vt
N5{C // NOTE - the ClassWizard will add and remove member functions here.
DVJc-.x8 // DO NOT EDIT what you see in these blocks of generated code !
FQFENq''B //}}AFX_MSG
Ic
K=E]p DECLARE_MESSAGE_MAP()
ry
?2 o! };
~@8d[Tb LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
2M?lgh4" BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
F4x7;?W{* BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
;ZJ,l)BNO BOOL InitHotkey();
,[\(U!Z7:% BOOL UnInit();
>Gu0& #endif
hD1AK+y >~rd5xlk //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
#!jRY!2Vt #include "stdafx.h"
<o+
7U #include "hook.h"
"yTh + = #include <windowsx.h>
w<Cmzkf #ifdef _DEBUG
_oTT3[7P #define new DEBUG_NEW
:XSc#H4 #undef THIS_FILE
UD2<!a'T static char THIS_FILE[] = __FILE__;
CLEG'bZa, #endif
=h::VB}Lv #define MAX_KEY 100
41o!2(e$ #define CTRLBIT 0x04
{@5WeWlz~ #define ALTBIT 0x02
RYl3txw #define SHIFTBIT 0x01
Qz+d[%Q}x #pragma data_seg("shareddata")
_c8.muQ< HHOOK hHook =NULL;
S7ehk*` UINT nHookCount =0;
(Dm"e` static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
SU
O; static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
B"m:<@ " static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
s}#[*WOc static int KeyCount =0;
gAA
%x7 static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
sNfb %r #pragma data_seg()
IIQ3|eZ HINSTANCE hins;
#A/J^Ko void VerifyWindow();
pq?[ wp" BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
:F>L;mp //{{AFX_MSG_MAP(CHookApp)
|M<.O~|D6} // NOTE - the ClassWizard will add and remove mapping macros here.
d50IAa^p6J // DO NOT EDIT what you see in these blocks of generated code!
A
Ok7G?Y //}}AFX_MSG_MAP
(U'7Fc END_MESSAGE_MAP()
.;Utkf'I J)8pqa CHookApp::CHookApp()
Ot$cmBhw! {
P}+|`>L // TODO: add construction code here,
qa$[L@h> // Place all significant initialization in InitInstance
EkStb# }
b6!Q!:GO& wAYzR$i CHookApp theApp;
0Dm`Ek3A7x LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
M,\|V3s {
h w ;d m BOOL bProcessed=FALSE;
jO&f*rxN if(HC_ACTION==nCode)
Z|:_c {
U.pr} hq if((lParam&0xc0000000)==0xc0000000){// Key up
;%rs{XO9 switch(wParam)
>b4YbLkI# {
-wtTq
ph' case VK_MENU:
@%G' U&R{ MaskBits&=~ALTBIT;
K*Nb_|~ break;
C*{15!d:G case VK_CONTROL:
1RI #kti-" MaskBits&=~CTRLBIT;
GwMUIevO_ break;
f`u5\!}=! case VK_SHIFT:
0l(E!d8&' MaskBits&=~SHIFTBIT;
igRDt{} break;
!8
wid& default: //judge the key and send message
kol,Qs break;
lrmt)BLoh }
mq{$9@3 for(int index=0;index<MAX_KEY;index++){
cy& if(hCallWnd[index]==NULL)
c<+g|@A# continue;
$LxG>db if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Bt*&L[&57 {
|~/3u/ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
nj~$%vmA bProcessed=TRUE;
(:&&;]sI }
f
gK2.;> }
mJGO)u& }
8"?Vcw& else if((lParam&0xc000ffff)==1){ //Key down
2rR@2Vsw2 switch(wParam)
e-%7F]e {
'FPcAW^8 case VK_MENU:
@wYQLZ MaskBits|=ALTBIT;
r6oX6.c break;
uS:
A4tN case VK_CONTROL:
S|{Yvyp MaskBits|=CTRLBIT;
1BMV=_ break;
DqurHQ z)m case VK_SHIFT:
AQnJxIL: MaskBits|=SHIFTBIT;
Pg*?[^* break;
]b0zkoD9< default: //judge the key and send message
c ,h.`~{ break;
+X* F<6mZ }
R\9>2*w for(int index=0;index<MAX_KEY;index++)
a gmeiJT {
r!=]Q}`F if(hCallWnd[index]==NULL)
\yJZvhUk continue;
m6bWmGnGC if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
2cs?("8e% {
k8InbX[ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
mC*W2#1pF bProcessed=TRUE;
i63`B+L{ }
8~&F/C* }
RJtixuvh@ }
tl{]gz if(!bProcessed){
1?D8|< for(int index=0;index<MAX_KEY;index++){
ZfFIX5Qd\ if(hCallWnd[index]==NULL)
uD. continue;
nu4Pc if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
7%:??*"~ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
-{yDk$" }
3n.+_ jQ>s }
'sm[CNzS }
Qv&T E3 return CallNextHookEx( hHook, nCode, wParam, lParam );
?Ia4H }
9O),/SH;: uuI3NAi~ BOOL InitHotkey()
ucQezmie {
Kwy1SyU if(hHook!=NULL){
T5K-gz7A nHookCount++;
pj!k|F9 return TRUE;
y-E1]4?}) }
q1N4X7<_ else
_Ct}%-,4 hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
QDIsC if(hHook!=NULL)
7ZF}0K$^B nHookCount++;
::p-9F return (hHook!=NULL);
8pXfT%] }
0^J*+ BOOL UnInit()
1k!D0f3qb {
,3G$` if(nHookCount>1){
X tJswxw`K nHookCount--;
!Bag}|# return TRUE;
"AT&!t[J }
Rb{+Ki BOOL unhooked = UnhookWindowsHookEx(hHook);
Q<z)q<e if(unhooked==TRUE){
Sv.KI{;v$ nHookCount=0;
ceqFQ hHook=NULL;
\U==f&G?J }
Zkw J.SuU return unhooked;
60~v
t04 }
0Wa#lkn$I cYsR0# BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
|c<XSX?ir {
cL6 6gOEL BOOL bAdded=FALSE;
aZ8h[#]7 for(int index=0;index<MAX_KEY;index++){
w(aUEWYL if(hCallWnd[index]==0){
|__d 8a hCallWnd[index]=hWnd;
fW(; HotKey[index]=cKey;
$B<~0'6} HotKeyMask[index]=cMask;
#1MKEfv(~ bAdded=TRUE;
,Yo: &>As KeyCount++;
pMOD\J:l, break;
4\v~HFsv }
'T%IvJ#Xu }
QT_Srw@ return bAdded;
TV<Aj"xw }
ki#y&{v9Be !
&y BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
S<*' ;{5~ {
C:Vv!u BOOL bRemoved=FALSE;
&Y{F?
c^ for(int index=0;index<MAX_KEY;index++){
/;+oz if(hCallWnd[index]==hWnd){
'wa g |- if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
|n)<4%i8J hCallWnd[index]=NULL;
T)`gm{T HotKey[index]=0;
'HCnB]1 HotKeyMask[index]=0;
k@7kNMl bRemoved=TRUE;
^Wf
S\M` KeyCount--;
vXc!Zg~ break;
\{lE0j7}h }
;jF%bE3 }
}lH;[+u3 }
0"4J"q]& return bRemoved;
v< Ty|(gd }
^[0"vtb O!/ekU|,r void VerifyWindow()
@#A!w;bz {
f KHse$?_ for(int i=0;i<MAX_KEY;i++){
$-Cy if(hCallWnd
!=NULL){ R^uc%onP
if(!IsWindow(hCallWnd)){ !f@XDW&R
hCallWnd=NULL; )t5;d
HotKey=0; ::ri3Tu
HotKeyMask=0; a`s/ qi
KeyCount--; ;e2Ij
} lz-
iCZ
}
PaNeu1cO
} Y^yG/F
} f*v1J<1#
.3( ;9};
BOOL CHookApp::InitInstance() X`D+jiQ(f
{ <;aJ#qT
AFX_MANAGE_STATE(AfxGetStaticModuleState()); CPVmF$A-
hins=AfxGetInstanceHandle(); ERp{gB2U?
InitHotkey(); RU7!U mf
return CWinApp::InitInstance(); 2?*||c==*
} ?/)lnj)e{
a/:]"`)
int CHookApp::ExitInstance() UP?D@ogl<
{ sLZ>v
VerifyWindow(); zs0hXxTY:
UnInit(); ZRPE-l_3:
return CWinApp::ExitInstance(); >GmN~"iJ
} ~x\Cmu9`
a&N