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:
$@_{p*q
?w-1:NWjt 一、实现方法
I%oRvg|q eP "`,< 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
v?L MDJc[am #pragma data_seg("shareddata")
(8.{+8o HHOOK hHook =NULL; //钩子句柄
j~bAbOX12
UINT nHookCount =0; //挂接的程序数目
iOX Z]Xj5 static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
m`z7fi7u static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
/
s,tY74'5 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
e@E17l- static int KeyCount =0;
#ZJMlJ:q`" static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
Vtr3G.P^ #pragma data_seg()
Ly;I,)w tJNIr5o 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
zh\$t]d<I 4o<*PPA1 DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
%}P4kEY CE uWw:) BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
(89Ji'dc cKey,UCHAR cMask)
',7a E@PJ {
<47k@Ym BOOL bAdded=FALSE;
7h%4] for(int index=0;index<MAX_KEY;index++){
*m9{V8Yi2 if(hCallWnd[index]==0){
LN4qYp6)G hCallWnd[index]=hWnd;
hoenQ6N^: HotKey[index]=cKey;
XVt/qb%)r HotKeyMask[index]=cMask;
e+. \pe\ bAdded=TRUE;
wd[eJcQ , KeyCount++;
ad9CsvW break;
4WC9US-k }
q*,Q5 }
u)a' return bAdded;
)P?IqSEA% }
re^Hc(8M //删除热键
!^e =P%S BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
'cV?i&; {
_T5)n=| BOOL bRemoved=FALSE;
B/G-Yh$E for(int index=0;index<MAX_KEY;index++){
/.Fj.6U5 if(hCallWnd[index]==hWnd){
U3E&n1AA if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
S,''>`w hCallWnd[index]=NULL;
3uV4/%U HotKey[index]=0;
|t))u`~ HotKeyMask[index]=0;
*RWm47 bRemoved=TRUE;
/)EY2Y' KeyCount--;
EF#QH
_X break;
[ %}u=}@ }
\ECu5L4 }
{hQ6K)s }
Iy';x return bRemoved;
<xo-Fv }
*/z??fI27 _OMpIdY,R* TW7:q83{l DLL中的钩子函数如下:
Z
o=]dBp. 1D F/6y LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
>xqM5#m`E$ {
(gwj)?: BOOL bProcessed=FALSE;
c0_E_~ if(HC_ACTION==nCode)
V5mlJml2( {
`]=oo%(h if((lParam&0xc0000000)==0xc0000000){// 有键松开
vi!YN|}\ switch(wParam)
['q&@_d7 {
t{dSX?<nt case VK_MENU:
AQss4[\Dx MaskBits&=~ALTBIT;
}fZ`IOf break;
u,1}h L case VK_CONTROL:
+/rH(Ni MaskBits&=~CTRLBIT;
,qQG;w,m break;
3GH(wSv9\ case VK_SHIFT:
k`\R+WK$ MaskBits&=~SHIFTBIT;
LOvHkk@+ break;
"Pz}@= default: //judge the key and send message
+*}{`L-
: break;
;
A,#;%j }
/KCPpERk{ for(int index=0;index<MAX_KEY;index++){
]]0,|My7 if(hCallWnd[index]==NULL)
6GAaV[])' continue;
;`dh
fcU if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
WGu%7e] {
x%N\5 V1 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
-c%dvck^, bProcessed=TRUE;
uH@FU60 }
f )Z%pgB }
t<j^q`;@v }
amWD-0V else if((lParam&0xc000ffff)==1){ //有键按下
$w#r"= ) switch(wParam)
#!2k<Q*5uT {
l|/LQ/ case VK_MENU:
-nbMTY} MaskBits|=ALTBIT;
1L nyWZ break;
dRi5hC$ case VK_CONTROL:
B@y(. MaskBits|=CTRLBIT;
_oFs #kW break;
2xwlKmI N case VK_SHIFT:
e@#kRklV& MaskBits|=SHIFTBIT;
5J2=`=FK break;
1ocJ+ default: //judge the key and send message
)$Mmn break;
B,WTHU[AV }
BvD5SBa}" for(int index=0;index<MAX_KEY;index++){
$wB^R(f@ if(hCallWnd[index]==NULL)
bFS>) continue;
Bux [6O% if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
d[D&J {
S6d`ioi- SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
7nU6k%_ % bProcessed=TRUE;
uC3:7 }
SOZPZUUEJ }
%dST6$Z }
&fC!(Oy if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
ao" %WX for(int index=0;index<MAX_KEY;index++){
Sh6JF574T if(hCallWnd[index]==NULL)
:1ecx$ continue;
:}:3i9e*2 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
mmXm\]r>4 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
+|iYg/2 //lParam的意义可看MSDN中WM_KEYDOWN部分
AK!hK>u` }
}n_p$g[Nj/ }
/93l74.w }
wC_l@7t return CallNextHookEx( hHook, nCode, wParam, lParam );
epHJ@ W@# }
nlYR-. +!IQj0&'Y3 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:
@Ky> 9m{ g7V8D BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
l_'[27 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
N==ZtKj F X~=xXN. 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:
}R[#?ty;] m([(:.X/IX LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
$rF=_D6 {
eN?Y7 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
LVJI_ O{fH {
7hW+T7u? //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
._w8J"E5 SaveBmp();
=L|tp%! return FALSE;
J_;N:7'p }
aNn"X y\ k …… //其它处理及默认处理
/M;#_+VK< }
aI(7nJ=R u%/fx~t$ H=*5ASc 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。
im} ?rY {Gq*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。
`1*nL,i oI:o"T77sA 二、编程步骤
=*qD4qYA &6 s) X 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";
A1)wo^, -oeL{9; 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
tM-^<V& VErv;GyV 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;
h&.wo ! G+xt5n.% 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;
D4eTTfQ tWTKgbj( 5、 添加代码,编译运行程序。
/+*#pDx/zW R[z`:1lo 三、程序代码
a,F&`Wg C51bc6V ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
CQ`=V2:"ON #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
_=ua6}Xp #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
^;,M}|<h #if _MSC_VER > 1000
a?|vQ*W #pragma once
Uoya3#4 G #endif // _MSC_VER > 1000
[ EFMu;q #ifndef __AFXWIN_H__
iovfo2!hD #error include 'stdafx.h' before including this file for PCH
Uz cx6sw #endif
2%*MW"Q #include "resource.h" // main symbols
{oc igR0 class CHookApp : public CWinApp
E$9Ys {
t?o,RN: public:
c_aZ{S CHookApp();
5D M"0 // Overrides
MuoF FvAA // ClassWizard generated virtual function overrides
g%F"l2M //{{AFX_VIRTUAL(CHookApp)
g(VNy@ public:
&l$Q^g virtual BOOL InitInstance();
%ms'n virtual int ExitInstance();
kGpa\c
g1 //}}AFX_VIRTUAL
-jgysBw+Xb //{{AFX_MSG(CHookApp)
#&v/icz$ // NOTE - the ClassWizard will add and remove member functions here.
M(#m0xB // DO NOT EDIT what you see in these blocks of generated code !
u2oKH{/z //}}AFX_MSG
|KB0P@=a DECLARE_MESSAGE_MAP()
:m86
hBE. };
D=:04V}2+ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
yC
77c= BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
UnVm1ZWZ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
.@
xF6UZ BOOL InitHotkey();
+("7ZK? BOOL UnInit();
@
'@:sM_ #endif
gaA<}Tp, s9dO,FMs0t //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
`1{N=!U(& #include "stdafx.h"
vvUSeG\n#j #include "hook.h"
DAo~8H #include <windowsx.h>
UAR5^ #ifdef _DEBUG
ycFio , #define new DEBUG_NEW
e8YMX&0% #undef THIS_FILE
m<L; static char THIS_FILE[] = __FILE__;
rc+C?)S #endif
988]}{w #define MAX_KEY 100
| mu+9 #define CTRLBIT 0x04
gP+fN$5'd #define ALTBIT 0x02
1c JF/"v #define SHIFTBIT 0x01
iU6Gp-<M, #pragma data_seg("shareddata")
r kiT1YTY HHOOK hHook =NULL;
AiD[SR UINT nHookCount =0;
Fnk_\d6Ma static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
-{^}"N static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
?+T^O?r|O static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
>]o}}KF? static int KeyCount =0;
.0R v(Y static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
\om%Q[F7a #pragma data_seg()
{3N'D2N HINSTANCE hins;
=^H4 Yck/5 void VerifyWindow();
eZ"1gYqy BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
cyxuK*x< //{{AFX_MSG_MAP(CHookApp)
3\T2?w9u( // NOTE - the ClassWizard will add and remove mapping macros here.
O;7)Hjw t // DO NOT EDIT what you see in these blocks of generated code!
f|u#2!7 //}}AFX_MSG_MAP
7JSNYTH END_MESSAGE_MAP()
eNiaM6(J jA#/Z CHookApp::CHookApp()
[r/k% < {
s; UH] // TODO: add construction code here,
hHqh{:q{v // Place all significant initialization in InitInstance
Kx_h1{ }
]Qm]I1P wP,JjPUt CHookApp theApp;
fDx9iHGv LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Mi~(aah {
+cU>k} BOOL bProcessed=FALSE;
qRbf2; if(HC_ACTION==nCode)
8w({\= {
;gC| if((lParam&0xc0000000)==0xc0000000){// Key up
fwzb!"!.@ switch(wParam)
V.wqZ {G {
64:fs?H case VK_MENU:
$%VuSrZ& MaskBits&=~ALTBIT;
p }[zt#v break;
=_YG#yS case VK_CONTROL:
qY 4#V k MaskBits&=~CTRLBIT;
$=?@*p break;
[pVamE case VK_SHIFT:
$ cj>2. MaskBits&=~SHIFTBIT;
`K,1K break;
G\NPV' default: //judge the key and send message
Zw
wqSyuGf break;
^&g=u5
d0 }
wcDRH)AW. for(int index=0;index<MAX_KEY;index++){
VbBPB5 $q if(hCallWnd[index]==NULL)
u{["50~ continue;
B c2p(z4 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
>vo=]cw {
y\{%\ $ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
ax
41N25 bProcessed=TRUE;
M:5b4$Qh< }
C*nB }
}MUn/ [x }
If%/3UJ@ else if((lParam&0xc000ffff)==1){ //Key down
Z4IgBn(Z_} switch(wParam)
'=P7""mN5 {
1
hg}(Hix case VK_MENU:
JmEj{K<3I MaskBits|=ALTBIT;
F: mq'<Q break;
0Ia($.1mY case VK_CONTROL:
7t.!lh5G% MaskBits|=CTRLBIT;
,]b~t0|B break;
ZoArQ(YFy case VK_SHIFT:
h;3cd0 MaskBits|=SHIFTBIT;
3j3N!T9 break;
&HSq(te default: //judge the key and send message
vzmc}y G break;
x`6<m!d` }
]vuwkn+) for(int index=0;index<MAX_KEY;index++)
r_;9'#&' {
/rSH"$ if(hCallWnd[index]==NULL)
Ks}Xgc\ continue;
TwgrRtj' if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
,!U=|c"k) {
&IlU|4`R% SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
H:"maS\I bProcessed=TRUE;
ul*Qt} }
)Pv9_XKJ }
}pJwj }
"1,pHR-+R if(!bProcessed){
0T46sm r for(int index=0;index<MAX_KEY;index++){
;qBu4'C)T if(hCallWnd[index]==NULL)
4 {9B9={ continue;
awz;z?~ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
%Z*sU/^ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
bu51$s?B }
n[(Qr9 }
+>4;Z d!@d }
r;m)nRu return CallNextHookEx( hHook, nCode, wParam, lParam );
f|sFlUu& }
)aX,% yK S6[v;{xJ BOOL InitHotkey()
>|;aIa@9 {
MeUaTJFEB if(hHook!=NULL){
@}kv-* nHookCount++;
xCtmXo return TRUE;
*_ ?dVhxf }
dXnl'pFS else
2=_gf hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
a. z;t8 if(hHook!=NULL)
Onwp-!!.
nHookCount++;
@'GGm#< return (hHook!=NULL);
]7e =fM9V; }
hqRw^2F BOOL UnInit()
u,6~qQczE {
}3?n~s\)6f if(nHookCount>1){
\_B[{e7z nHookCount--;
XU"~h64] return TRUE;
{GJ@psG* }
J(6oL BOOL unhooked = UnhookWindowsHookEx(hHook);
L5,NP5RC if(unhooked==TRUE){
5ls6t{Ci nHookCount=0;
-{ZWo:,r~q hHook=NULL;
__.+s32SS$ }
)wNP(
@$L return unhooked;
A,4fEmWM }
){UcS/GI= y '!m4- BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
.?l\g-;= {
8Ac:_Zg BOOL bAdded=FALSE;
~*wk6&| for(int index=0;index<MAX_KEY;index++){
tToTxf~ if(hCallWnd[index]==0){
7nuU^wc hCallWnd[index]=hWnd;
AnT3M.>ek HotKey[index]=cKey;
|6<p(i7 HotKeyMask[index]=cMask;
q`r**N+zn bAdded=TRUE;
l'eyq}& KeyCount++;
6R^^ .tCs break;
8-O)Xx}cU }
$*?,#ta }
)6aAB| return bAdded;
r9dyA5oD }
G["c\Xux w`5xrqt@ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
s)pbS}L {
Sm5H_m! BOOL bRemoved=FALSE;
v\{!THCSh for(int index=0;index<MAX_KEY;index++){
Q 7?#=N? if(hCallWnd[index]==hWnd){
Bs?^2T~%{ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
JeE;V![ hCallWnd[index]=NULL;
d N$Tf HotKey[index]=0;
E@b(1@ HotKeyMask[index]=0;
)KAEt.
bRemoved=TRUE;
GN2Sn`; KeyCount--;
lg&t8FHa; break;
pfI"36]F }
Nal9M[]c }
jB(|";G }
9B9(8PVG return bRemoved;
5^x1cUB] }
y_?Me] j?+X\PtQ void VerifyWindow()
-jiG7OL {
OtNd,U.dE for(int i=0;i<MAX_KEY;i++){
2=^m9% if(hCallWnd
!=NULL){ n<u
$=H
if(!IsWindow(hCallWnd)){ f=9|b
hCallWnd=NULL; qXwPDq/
HotKey=0; r%+V8o
HotKeyMask=0; pS7w' H
KeyCount--; aYSCw3C<
} t)}scf&^x
} _/tHD]um
} 9c("x%nLpB
} tw9f%p
l~$+,U&XNe
BOOL CHookApp::InitInstance() B]l)++~
{ y9Us n8
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 5yz(>EVH
hins=AfxGetInstanceHandle(); _BP&n