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:
E7.{SGH}
=h?%<2t9< 一、实现方法
C
OL"/3r Fi 7~JZZ 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:
R<hsG%BS(D O*N:.|dUw #pragma data_seg("shareddata")
1W-kZ(e HHOOK hHook =NULL; //钩子句柄
Lpnw(r9Y UINT nHookCount =0; //挂接的程序数目
0B2f[A static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
"4T36b static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
s<:);-tL static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
33a}M;vx static int KeyCount =0;
y5D3zqCG static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
|mdf u= #pragma data_seg()
0R0_UvsXU n$h+_xN 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。
$GQEdVSNo ^JY:$)4[" 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!HEi<F ti]8_vP}* BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
teLZplC=f cKey,UCHAR cMask)
5p-vSWr! {
+# !?+'A BOOL bAdded=FALSE;
BLt_(S?Z` for(int index=0;index<MAX_KEY;index++){
: Q2=t! if(hCallWnd[index]==0){
usu{1&g hCallWnd[index]=hWnd;
q[Ey!h)xq HotKey[index]=cKey;
hY *^rY' HotKeyMask[index]=cMask;
6Bd:R}yZP7 bAdded=TRUE;
Uxe]T KeyCount++;
7|[Dr@.S break;
C\;%IGn }
t: ,lz8Y~ }
C.H(aX)7 return bAdded;
<]#_&Na }
VG$%Vs //删除热键
Tc/<b2\g BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
CPY|rV {
B{S^t\T$ BOOL bRemoved=FALSE;
'~z`kah for(int index=0;index<MAX_KEY;index++){
1-<?EOYaE if(hCallWnd[index]==hWnd){
!wKNYe if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
?i!d00X hCallWnd[index]=NULL;
>>;He7 HotKey[index]=0;
x
#|t#N% HotKeyMask[index]=0;
JuRWR0@` bRemoved=TRUE;
An,TunX KeyCount--;
w*(1qUF#% break;
,wHlU-% }
=BV_? }
s%m?Yh3 }
M?n}{0E4 return bRemoved;
mM+^v[= }
h^w# I S3QX{5t\ !HW?/-\,O DLL中的钩子函数如下:
O-~cj7
0\
!NKPy+v LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
w2`JFxQ^x {
62[_u]<Yub BOOL bProcessed=FALSE;
6pZ/C<Y|W if(HC_ACTION==nCode)
G!Y7RjWD {
O\@0o|NM if((lParam&0xc0000000)==0xc0000000){// 有键松开
r-[YJzf@P switch(wParam)
9):^[Wkx {
}Py Z{yS case VK_MENU:
Z%SDN"+'g MaskBits&=~ALTBIT;
?fpI,WFu break;
O31.\ZR2 case VK_CONTROL:
|+<o(Q( MaskBits&=~CTRLBIT;
[W dxMU break;
c.>OpsF case VK_SHIFT:
S6_dmTV* MaskBits&=~SHIFTBIT;
0nR_I^ break;
<4;L&3 default: //judge the key and send message
8lCo\T5" break;
'(3|hh)Tl }
cz$*6P<9J for(int index=0;index<MAX_KEY;index++){
<#T#+uO if(hCallWnd[index]==NULL)
0Yr-Q;O<f continue;
OPv~1h<[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
e4.G9( {
:<1PCX2 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
lXnv(3j3*s bProcessed=TRUE;
Dkg-y9 }
CzmB76zy. }
Z22#lF\ N }
K#yCZ2 else if((lParam&0xc000ffff)==1){ //有键按下
zWF[cf>' switch(wParam)
d#I; e {
8Urj;KkD case VK_MENU:
S;nlC MaskBits|=ALTBIT;
<*ME&cgh4 break;
DM(c :+K- case VK_CONTROL:
^X:g C9 MaskBits|=CTRLBIT;
.bRDz:?j break;
bHzH0v]: case VK_SHIFT:
cNl$
vP83z MaskBits|=SHIFTBIT;
v0pev;C break;
5&134!hC default: //judge the key and send message
0j' Xi_uM break;
Y1{*AV6ev6 }
eTY(~J#' for(int index=0;index<MAX_KEY;index++){
`EVy if(hCallWnd[index]==NULL)
{iTA=\q2O continue;
L@G~9{U> if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
M,DwBEF? {
4z qO!nk SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
j3/K;U/SGJ bProcessed=TRUE;
"z{rC} }
<bh!wf6; }
:8lqo%5 }
R^JtWjJR if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
nYnv.5 for(int index=0;index<MAX_KEY;index++){
Dq*O8*#* if(hCallWnd[index]==NULL)
(;++a9GK continue;
!L@a;L if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
*1U"uJno SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
D<bHRtP //lParam的意义可看MSDN中WM_KEYDOWN部分
l9{.~]V }
G"*ch$: }
YH0utc }
Ve[&_(fP return CallNextHookEx( hHook, nCode, wParam, lParam );
-8Uz8//A }
}FC(Z-g 'L
veCi_ 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:
:g)`V4% hx;0h&L BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
L#u!T)!zW BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
H\=S_b1wo -JXCO<~k 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:
9Pdol! 2P?|'U LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
Q::_i"?c {
_Xfn if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
JZoH - {
$HFimU,V=0 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
B>e},! SaveBmp();
?&@a{- return FALSE;
j\uPOn8k }
>s>{+6e …… //其它处理及默认处理
Uc]sWcR }
x I(X+d`` Y;>D"C.. PO]c&}/ 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
o/I`L *|3G"B{w6 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
dZ,~yV tP|ox] 二、编程步骤
-D^v:aC %j;mDR95 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
K,f-
w2! SG-Xgr@ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
h`V#)Q i0{sE 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
[?VkwFD0 7DWHADr 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
42.y.LtZ ::p(ViYG 5、 添加代码,编译运行程序。
<4D.H .2QZe8" 三、程序代码
~L=? F ge$ p/ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
k\}\>&Zqu #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
n4DKLAl #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
ITBa ^P #if _MSC_VER > 1000
^7V{nT@H3 #pragma once
M1e79p< #endif // _MSC_VER > 1000
ZKoISuM #ifndef __AFXWIN_H__
H.!\j&4j #error include 'stdafx.h' before including this file for PCH
Bx ru7E" #endif
&>3AL, #include "resource.h" // main symbols
Og9:MFI class CHookApp : public CWinApp
=g$>]AE {
}/.GB5Ej public:
KDJ-IXoU CHookApp();
[D<"qT^*z6 // Overrides
?9:~d#p // ClassWizard generated virtual function overrides
2D'$ //{{AFX_VIRTUAL(CHookApp)
3 UG
UZ public:
,];QzENw virtual BOOL InitInstance();
W$Op/ virtual int ExitInstance();
5HW'nhE //}}AFX_VIRTUAL
g66SCr} //{{AFX_MSG(CHookApp)
;hJz'&UWQ // NOTE - the ClassWizard will add and remove member functions here.
P] qL&_ // DO NOT EDIT what you see in these blocks of generated code !
\CZD.2p#& //}}AFX_MSG
NrWgaPO)i DECLARE_MESSAGE_MAP()
=4:]V\o):' };
)o_Pnq9_ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
1'BC
R BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
`z?h=&N BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
6w4}4i BOOL InitHotkey();
[F}_Ime BOOL UnInit();
[IPXU9&Q #endif
Ae_:Kc6 ExZ|_7^< //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
+`'> #include "stdafx.h"
>4]y)df5 #include "hook.h"
!A&>Eeai #include <windowsx.h>
@ACq:+/Qc #ifdef _DEBUG
zF#:Uc`C5U #define new DEBUG_NEW
!6l}s$1i| #undef THIS_FILE
rtZEK:.# static char THIS_FILE[] = __FILE__;
ja+PVf #endif
]r(s02 #define MAX_KEY 100
aW;DfH #define CTRLBIT 0x04
L_Lhmtm}m #define ALTBIT 0x02
@agxu-Y #define SHIFTBIT 0x01
KU*XRZu) #pragma data_seg("shareddata")
9;`E,w HHOOK hHook =NULL;
<@J0
770 UINT nHookCount =0;
ECr}7R% static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
xpB*>zb static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
Wr;9Mz&{ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
V~"-\@ static int KeyCount =0;
}^zsN` static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
tu5T^"BqO #pragma data_seg()
6QG"~>v7'( HINSTANCE hins;
4-JyK%m,0 void VerifyWindow();
W9/HM ! BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
S$ Z?T //{{AFX_MSG_MAP(CHookApp)
}ISc^W) t // NOTE - the ClassWizard will add and remove mapping macros here.
=.ReM_. // DO NOT EDIT what you see in these blocks of generated code!
Ktn:6=, //}}AFX_MSG_MAP
#-8%g{ END_MESSAGE_MAP()
pra0:oHN "-:-!1;Ji CHookApp::CHookApp()
vhKHiw9L {
cE+Y#jB // TODO: add construction code here,
IT:8k5(L5j // Place all significant initialization in InitInstance
ZFNg+H/k }
u{%dm5 ;U]Ym48 CHookApp theApp;
*dPG[ } LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
QHgkfo {
f yhBfA:u BOOL bProcessed=FALSE;
[SU;U['7 if(HC_ACTION==nCode)
kB-]SD# {
_DLELcH
Y if((lParam&0xc0000000)==0xc0000000){// Key up
0rCQz3gh1 switch(wParam)
pI1IDu*_Z {
fHiS'R case VK_MENU:
1Ms_2 MaskBits&=~ALTBIT;
8M8Odz\3 q break;
X|dlVNL8p case VK_CONTROL:
1w'W)x MaskBits&=~CTRLBIT;
6\vaR# break;
yz^4TqJ case VK_SHIFT:
T$*#q('1"} MaskBits&=~SHIFTBIT;
0t2n7Y?N break;
^50\c$ default: //judge the key and send message
V2>+s
y break;
e>g>)!F }
!v<`^`x9I for(int index=0;index<MAX_KEY;index++){
-
`{T ? if(hCallWnd[index]==NULL)
N<^)tR8+ continue;
{iYrC m[_ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
V-kx=M"k {
x,LYfy"0 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
!4+ FN) bProcessed=TRUE;
KtD
XB> }
Hb3t|<z }
__|Y59J% }
;.Y-e
Q, else if((lParam&0xc000ffff)==1){ //Key down
@wcrtf~{)& switch(wParam)
/_1q)`NYy {
/B)`pF.n case VK_MENU:
K@tEL Yb MaskBits|=ALTBIT;
-S7i': break;
KpC!C9 case VK_CONTROL:
Of
m0{c= MaskBits|=CTRLBIT;
/p$+oA+ break;
`wKd##v'@ case VK_SHIFT:
Af Y]i MaskBits|=SHIFTBIT;
U3~rtc* break;
G.]'pn default: //judge the key and send message
!3`X Gg break;
jx14/E+^ }
qW`DCZu for(int index=0;index<MAX_KEY;index++)
$
D.*r*c6 {
u4|)A4n if(hCallWnd[index]==NULL)
^j7>Ul, continue;
*JF7 B if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
`Gh J)WA< {
pU1miA ' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
I(>j"H)cAF bProcessed=TRUE;
m
;yIFO }
3v~[kVhoG }
u4h.\ul8% }
=
( 4l if(!bProcessed){
^~^=$fz for(int index=0;index<MAX_KEY;index++){
h?p!uQ if(hCallWnd[index]==NULL)
{LBL8sG continue;
lf#5X)V if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
=
OzpI SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
r6vI6|1 }
$bl<mG%#9 }
-+[~eqRB }
>?[?W|k7V return CallNextHookEx( hHook, nCode, wParam, lParam );
'0v]?mM }
iLQ;`/j BvP++,a&Sa BOOL InitHotkey()
-?w3j9kk> {
'&/~Sh$% if(hHook!=NULL){
|_ OoD9,M nHookCount++;
%LBf'iA return TRUE;
2TgS
) }
uAu'2M,_ else
9r>iP L2H hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
9SXpZ*Sx if(hHook!=NULL)
JqV}$E"M2 nHookCount++;
<[vsGUbc return (hHook!=NULL);
:9f 9Z7M }
AjJ/t4< BOOL UnInit()
kn+@)3W:* {
+2>, -V if(nHookCount>1){
.EZ8yJj1Q nHookCount--;
ssAGWP return TRUE;
?(M$r\\ }
baGV]=j BOOL unhooked = UnhookWindowsHookEx(hHook);
e5(c,,/ if(unhooked==TRUE){
.|0$?w nHookCount=0;
vI]V@il hHook=NULL;
=R*IOJ }
p-*{x return unhooked;
cZ3A~dTOR }
A3|2;4t +mN8uU~(kx BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
NfZC} {
+xQj-r)- BOOL bAdded=FALSE;
g){gF( for(int index=0;index<MAX_KEY;index++){
@(IA:6GN if(hCallWnd[index]==0){
5t|$Yt[ hCallWnd[index]=hWnd;
LI>Bl HotKey[index]=cKey;
<?%49 HotKeyMask[index]=cMask;
:XOjS[wBm bAdded=TRUE;
%4})_h?j KeyCount++;
KQ0f2? break;
>:h&5@^j$ }
lQxEiDIL }
ra8AUj~RX return bAdded;
$3xDjiBb }
*0m|`-
T 3;88a!AA! BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
P MI?PC[; {
:s1.TQ;Y( BOOL bRemoved=FALSE;
eQ,VK`7X for(int index=0;index<MAX_KEY;index++){
qB+OxyT& if(hCallWnd[index]==hWnd){
'sTc=*p/ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
\F)WUIK hCallWnd[index]=NULL;
JOyM#g9-? HotKey[index]=0;
%qEp{itq HotKeyMask[index]=0;
r{f$n bRemoved=TRUE;
2OjU3z<J KeyCount--;
"]W,,A- break;
5sSAH }
?rziKT5OOC }
}{mS" }
$ago return bRemoved;
fKO@Qx] }
qDgy7kkQ goND S5} void VerifyWindow()
bK{ VjXF {
js!C`]1 for(int i=0;i<MAX_KEY;i++){
Kd\d>&b if(hCallWnd
!=NULL){ X9?0`6Li
if(!IsWindow(hCallWnd)){ HY;kV6g{P
hCallWnd=NULL; /J9Or{#r
HotKey=0; 0IZF%`
HotKeyMask=0; %3.
np
KeyCount--; ,;Uf>8~
} Hs6Kki1
} A@-U#UvN
} dj}|EW4
} UzW]kY[A<
=CO'LyG
BOOL CHookApp::InitInstance() s[VYd:}se
{ c4zGQoeH:
AFX_MANAGE_STATE(AfxGetStaticModuleState()); olKM0K
hins=AfxGetInstanceHandle(); )u0/s'
InitHotkey(); 4UND;I&
return CWinApp::InitInstance(); [;UI8Stw
} OzR<jCOS
2`A[<