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:
s_ bR]G
3fr ^ T 一、实现方法
/ty?<24ko "A3dvr 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:
)TJS4? .DguR2KT #pragma data_seg("shareddata")
Vz%OV}\ HHOOK hHook =NULL; //钩子句柄
\9:wfLF8! UINT nHookCount =0; //挂接的程序数目
4=[7Em?oLb static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
x /mp=
static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
L{8;Ud_2r static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
$_D6_|HK static int KeyCount =0;
6f)2 F<
7 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
HpW 42 #pragma data_seg()
SVWIEH0? #sB,1" 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
bRo|uJ:d d]wD[] DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
86qI u\1>gDI )| BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
>v+jh(^ cKey,UCHAR cMask)
h7yqk4'Lq {
}-DE`c BOOL bAdded=FALSE;
3
hKBc0 for(int index=0;index<MAX_KEY;index++){
kc$)^E7 if(hCallWnd[index]==0){
,Zf
9RM hCallWnd[index]=hWnd;
T:iP="?{ HotKey[index]=cKey;
V416g |lBO HotKeyMask[index]=cMask;
9X}I> bAdded=TRUE;
OJO!FH) KeyCount++;
+T{'V^ break;
w:i:~f . }
S :bC[} }
JXqr3Np1 return bAdded;
g);^NAA }
EbY,N:LK //删除热键
3ec`Wa
BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
tt_o$D~kg {
M8&}j BOOL bRemoved=FALSE;
&&>tf%[ for(int index=0;index<MAX_KEY;index++){
.)tSg if(hCallWnd[index]==hWnd){
1bnBji if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
c=O,;lWFqm hCallWnd[index]=NULL;
L1{GL #qV HotKey[index]=0;
U(>4s]O6 HotKeyMask[index]=0;
,:Z^$ bRemoved=TRUE;
3VO2,PCZ KeyCount--;
/ ~%KVe break;
<UP
m=Hb }
"SxLN
8.: }
|SZo'
6 }
'9p@vi{\ return bRemoved;
DOS0;^f }
||7x;2e BR`ygrfe DTRJ/@t DLL中的钩子函数如下:
/^SAC%PD }|OaL*|u LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
/*FH:T<V {
uA tV". BOOL bProcessed=FALSE;
d[^KL;b?6 if(HC_ACTION==nCode)
z4%uN|V {
ipnV$!z if((lParam&0xc0000000)==0xc0000000){// 有键松开
HAz By\M{ switch(wParam)
|077Sf| {
3rW|kkn case VK_MENU:
'NjzgZ~]P MaskBits&=~ALTBIT;
7,qYV} break;
:$;Fhf<5 case VK_CONTROL:
a]17qMl MaskBits&=~CTRLBIT;
7w:ef0S break;
.~A*= case VK_SHIFT:
GYxM0~:$k MaskBits&=~SHIFTBIT;
8H,4kY?Z break;
]B"'}%>ez default: //judge the key and send message
jdZ~z#`(!: break;
!)"%),>}o }
GE;e]Jkjn for(int index=0;index<MAX_KEY;index++){
mYN7kYR}<` if(hCallWnd[index]==NULL)
/-_=nf}w continue;
h+p*=|j` if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
,j;m!V {
EF7+ *Q9 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
k(>h^ bProcessed=TRUE;
o+`6LKg; }
ptatzp]c# }
6vuq1 }
oVA?J%EK else if((lParam&0xc000ffff)==1){ //有键按下
w{[=l6L m switch(wParam)
fH`P[^N {
P./V6i<: case VK_MENU:
X'. qYsS MaskBits|=ALTBIT;
\P} p5k[ break;
8`4<R6]LKB case VK_CONTROL:
PWh^[Rd) MaskBits|=CTRLBIT;
!TZhQiorC break;
U~h'*nV& case VK_SHIFT:
yKYUsp MaskBits|=SHIFTBIT;
'1,,)U#6E break;
t*@2OW`! default: //judge the key and send message
lzw3= H break;
&PkLp4mQ }
}X x(^Zh for(int index=0;index<MAX_KEY;index++){
b'VV'+| if(hCallWnd[index]==NULL)
mRB continue;
o7mZzzP if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
{x'GJtpb {
VrZ>bma; SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
REZJ}%}/ bProcessed=TRUE;
x~.:64 }
5H=ko8fZ= }
M?= ;JJ: }
/Q,{?';~ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
MCU_Z[N#10 for(int index=0;index<MAX_KEY;index++){
.(pN5JI* if(hCallWnd[index]==NULL)
Q{k
At% continue;
8G5Da|\ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
zBO(`=| SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
[((;+B //lParam的意义可看MSDN中WM_KEYDOWN部分
wApMzZ(X2y }
*Z m^
~Vo }
)tCX
y4 }
-n'F v@U return CallNextHookEx( hHook, nCode, wParam, lParam );
)c l5B{1P }
Zy|Mz& sp@E8G%xO 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:
,K:ll4{b
#gm)dRKm% BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
SP|<Tny BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
hFiIW77s2 piU/& 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:
c/_+o;Bc M$0u1~K LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
-s 6![eV {
aR\\<due if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
L`th7d" {
e</$ s //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
`R"I;qV SaveBmp();
bT
2a40ul return FALSE;
bzdb|I6Z }
<C9 XX~ …… //其它处理及默认处理
{EdH$l>94 }
-l%J/ : ~rjTF! ]v#r4Ert 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
*>VVt8*Et ;<0LXYL; 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
@iEA:?9uX rHP%0f9: 二、编程步骤
WD'#5]#Y d|T!v 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
"*,XL
uv> RZ1
/#; 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
y>*xVK{D Fq9Q+RNMZL 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
TNQP"9[? 0euuT@_$ 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;
1xv8gC:6 V5 U?F6 5、 添加代码,编译运行程序。
Z'H5,)j0R g#]wLm# 三、程序代码
/x{s5P3 KRjV}\} ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
9}z0J #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
#$3yz'"QF #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
-R{V- #if _MSC_VER > 1000
si4don #pragma once
nNXgW #endif // _MSC_VER > 1000
|AC1\)2tT #ifndef __AFXWIN_H__
4[r/}/iGo #error include 'stdafx.h' before including this file for PCH
ki>~H!zB #endif
HNL42\Kz! #include "resource.h" // main symbols
x1 1U@jd+1 class CHookApp : public CWinApp
<w\:<5e ' {
K!,<7[MBg public:
jSc#+_y CHookApp();
zS]8V?` // Overrides
XR!us/U`a // ClassWizard generated virtual function overrides
-|rLs$V1r //{{AFX_VIRTUAL(CHookApp)
Xv@SxS-5l public:
_4 cvX virtual BOOL InitInstance();
<_(/X,kBK virtual int ExitInstance();
c)0amM //}}AFX_VIRTUAL
$wYFEz //{{AFX_MSG(CHookApp)
>hH0Q5aL // NOTE - the ClassWizard will add and remove member functions here.
jmg!Ml // DO NOT EDIT what you see in these blocks of generated code !
pKS
{ 6P //}}AFX_MSG
{-BRt)L[ DECLARE_MESSAGE_MAP()
f3|@|'
; };
](F#`zUQ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
9_sA&2P{uV BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
rxme(9M BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
MQ)L:R`L BOOL InitHotkey();
rWh6RYd<T BOOL UnInit();
Cye$H9 2 #endif
cQ:"-!ff gT/@dVV //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
RmrL^asg #include "stdafx.h"
-)vEWn$3< #include "hook.h"
2YuN~- #include <windowsx.h>
%&
_V0R\k #ifdef _DEBUG
exdx\@72 #define new DEBUG_NEW
nADX0KI #undef THIS_FILE
!`bio cA static char THIS_FILE[] = __FILE__;
,7XtH>2s #endif
SR*wvQnOx #define MAX_KEY 100
?|e'Gbb_ #define CTRLBIT 0x04
(Z5##dS3 #define ALTBIT 0x02
@E.k/G!~Nb #define SHIFTBIT 0x01
1
y}2+Kk #pragma data_seg("shareddata")
! Q<>3xZ HHOOK hHook =NULL;
"7>>I D UINT nHookCount =0;
f&D]anf33 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
8}w6z7e|{ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
w:'dhr': static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
Ap{}^ static int KeyCount =0;
G|8%qd static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
.WQ<jZt> #pragma data_seg()
,<DB&&EV8 HINSTANCE hins;
(z$r :p void VerifyWindow();
~ d^<_R BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
;6
+}z~ //{{AFX_MSG_MAP(CHookApp)
.Wi{lt // NOTE - the ClassWizard will add and remove mapping macros here.
a^5^gId5l! // DO NOT EDIT what you see in these blocks of generated code!
A[WV'!A, //}}AFX_MSG_MAP
|#l= END_MESSAGE_MAP()
Z>)][pL G;3~2^lB\ CHookApp::CHookApp()
zY+Fl~$S {
>+5?F*`\D* // TODO: add construction code here,
;V<iL? // Place all significant initialization in InitInstance
DP/J(>eG }
$hxNhI >!6i3E^ CHookApp theApp;
)EyI0R] 5 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
+jC*'7p@ {
OdI\B BOOL bProcessed=FALSE;
Hx$c
N if(HC_ACTION==nCode)
9;%CHb& {
*c[2C if((lParam&0xc0000000)==0xc0000000){// Key up
S]sk7 switch(wParam)
%7`f{|. {
}6 5s'JB case VK_MENU:
qW 1V85FG MaskBits&=~ALTBIT;
G,= yc@uq break;
:ug4g6;#H0 case VK_CONTROL:
fx8EB8A7K7 MaskBits&=~CTRLBIT;
QCPID: break;
>s3gqSDR case VK_SHIFT:
fQ+VT|jzx MaskBits&=~SHIFTBIT;
[~D|peM3 break;
:`)~-`_ default: //judge the key and send message
*=Z26 break;
QH]M }
~tB;@e for(int index=0;index<MAX_KEY;index++){
.ut{,(5 if(hCallWnd[index]==NULL)
j<%])
continue;
2fIRlrA$ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
(eCFWmO {
ECa$vvK
m SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
9s
+z B bProcessed=TRUE;
hgRVwX }
{J/I-=CmML }
zq5'i!s !0 }
z<gu00U7 else if((lParam&0xc000ffff)==1){ //Key down
f^e6<5gdf switch(wParam)
^5=UK7e5KY {
sM1RU case VK_MENU:
EPW7+Ve MaskBits|=ALTBIT;
c':ezEaC break;
C9S@v D+ case VK_CONTROL:
W&:[r/8wA MaskBits|=CTRLBIT;
zBf-8]"^ break;
!e#xx]v3 case VK_SHIFT:
ihT~xt MaskBits|=SHIFTBIT;
URcR break;
%[<Y9g,:Q default: //judge the key and send message
o-7>eE}+ break;
!\[+99F# }
~`Qko-a& for(int index=0;index<MAX_KEY;index++)
M^rM-{?< {
Hg}I]!B if(hCallWnd[index]==NULL)
`P+(&taT continue;
U3vEdw<lV if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
[-*F"}D, {
~#:e *:ro SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
lhC6S'vq bProcessed=TRUE;
.DJDpP)M }
f<y&\'3 }
'UM!*fk7C }
SN+S6 if(!bProcessed){
Jeqxspn
T for(int index=0;index<MAX_KEY;index++){
%>Xr5<$:& if(hCallWnd[index]==NULL)
-U2mfW continue;
sPNfbCOz if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
(g :p5Rl SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
M/V(5IoP( }
$mco0%$ }
zvv:dC/p< }
)He#K+[}^4 return CallNextHookEx( hHook, nCode, wParam, lParam );
fm1X1T . }
dw@E) ]8 U ~Iy BOOL InitHotkey()
]0c Pml {
IKvBf'%- if(hHook!=NULL){
^c9ThV.v nHookCount++;
J."{<& return TRUE;
fUag1d }
rlok%Rt4Z else
}\v^+scD hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
5IMSNGS if(hHook!=NULL)
{g/wY%u= nHookCount++;
dGH_ z8 return (hHook!=NULL);
`!\ivIi^ }
0/]_nd BOOL UnInit()
!>;w!^U {
%|3e.1oX if(nHookCount>1){
}IUP5O6 nHookCount--;
<z#BsnjW{ return TRUE;
Zcd7*EBdx }
twqFs BOOL unhooked = UnhookWindowsHookEx(hHook);
zCXqBuvu1 if(unhooked==TRUE){
[ET6(_=b nHookCount=0;
DM7}&~ hHook=NULL;
1JTbCS }
9+CFRYC return unhooked;
zjbE 7^N }
PNF4>)
AvRcS]@= BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Pw}_[[>$ {
[J\DB)V/ BOOL bAdded=FALSE;
+h[e0J|v{ for(int index=0;index<MAX_KEY;index++){
p?rK`$U+J if(hCallWnd[index]==0){
;?6>mh(` hCallWnd[index]=hWnd;
i|2$8G3 HotKey[index]=cKey;
\ 3NS>v[1 HotKeyMask[index]=cMask;
I"!'AI- bAdded=TRUE;
KvFR8s KeyCount++;
V> a*3D break;
5]"BRn1* }
XK 3]AYH }
<GW R7rUH return bAdded;
J6|JWp }
HY;oy( cIw
eBDl BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
;bHfn-X {
oXc/#{NC BOOL bRemoved=FALSE;
*8!w&ME+. for(int index=0;index<MAX_KEY;index++){
A|vP$zy if(hCallWnd[index]==hWnd){
_%IqjJO{=r if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
;e;\q;GP hCallWnd[index]=NULL;
>_Uj?F: HotKey[index]=0;
k8&FDz HotKeyMask[index]=0;
Fe="EDh bRemoved=TRUE;
?R?Grw)`H KeyCount--;
r=csi break;
CM 9P"- }
\.>.c g }
g37q/nEv }
G*\sdBW!k return bRemoved;
_'JRo%{xGX }
CX+9R3pa g3rRhS void VerifyWindow()
ltEF:{mLe# {
{'IFWD. 5 for(int i=0;i<MAX_KEY;i++){
{% F`%_{" if(hCallWnd
!=NULL){ x}"Q8kD
if(!IsWindow(hCallWnd)){ >~&(P_<b
hCallWnd=NULL; x YT}>#[
HotKey=0; B
T7Id
HotKeyMask=0; 8IWwjyRr
KeyCount--; *CUdGI&
} G.ud1,S#
} IIP.yyh>
} 2Guvze_bU
} <|JU(B
uu3M{*}
BOOL CHookApp::InitInstance() i`~~+6`J
{ + zDc
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 6$z'wy/*
hins=AfxGetInstanceHandle(); VG\mo?G
InitHotkey(); "
Z;uu)NE
return CWinApp::InitInstance(); LVmY=d>
} N *1
*tG11gR,&