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:
?Sj>b
#S4lRVt5 一、实现方法
lq'MLg (8Ptuh6\\2 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:
\-`,fat mG\$W#+j #pragma data_seg("shareddata")
u2 a#qU5* HHOOK hHook =NULL; //钩子句柄
VvFMpPi UINT nHookCount =0; //挂接的程序数目
ahoXQ8c:\} static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
5 *R{N
~> static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
'zo]
f static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
MrU0Jrk4+ static int KeyCount =0;
|&49YQ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
,h<xL- #pragma data_seg()
kN~:Bh$ d}:eLC 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。
<6rc8jYz ' pN[H\Ia 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:
I5%#A/|z 4AWL::FU5 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
Q4R*yRk cKey,UCHAR cMask)
d!P3<:+R[ {
7ciSIJ BOOL bAdded=FALSE;
iZ( U] for(int index=0;index<MAX_KEY;index++){
Gv(?u if(hCallWnd[index]==0){
P Y&(ObC hCallWnd[index]=hWnd;
>.=v*\P HotKey[index]=cKey;
o)]mJb~XG- HotKeyMask[index]=cMask;
U0J_
3W bAdded=TRUE;
1OI/,y8} KeyCount++;
G(;hJ'LT break;
^!v{
>3 }
,wYA_1$$H }
Q1[3C( return bAdded;
qP k`e}D }
ASU.VY //删除热键
ou\M}C`E BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
ud
grZ/w] {
\?_M_5Nb BOOL bRemoved=FALSE;
QWQJSz5 for(int index=0;index<MAX_KEY;index++){
umo<9Y if(hCallWnd[index]==hWnd){
eYQPK?jo if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
7cQFH@SC hCallWnd[index]=NULL;
[C^&iLX/F* HotKey[index]=0;
%
|^V) HotKeyMask[index]=0;
pf8M0,AY bRemoved=TRUE;
.+d.~jHX KeyCount--;
E#zLm break;
k}&7!G@T }
4 \Ig<C9 }
q]2t3aY% }
p6c&vEsNj return bRemoved;
1DRih>+# }
Kt5k_9 , G2(l /$'|`jKsB DLL中的钩子函数如下:
M 8NWQ^Y 4.e0k<]N` LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
%y|L'C,ge" {
MLT^7'y BOOL bProcessed=FALSE;
UP .4# 1I if(HC_ACTION==nCode)
X#Sgf|$ {
0&$,?CL?
if((lParam&0xc0000000)==0xc0000000){// 有键松开
I83 _x|$FZ switch(wParam)
5<$8.a# {
roM!%hb case VK_MENU:
93VbB[w~7F MaskBits&=~ALTBIT;
J?%e cCN break;
w.o>G2u case VK_CONTROL:
K6EG"Vv! MaskBits&=~CTRLBIT;
@#QaaR;4 break;
`e[>S case VK_SHIFT:
7R7e3p,K MaskBits&=~SHIFTBIT;
6>NK2} ` break;
:*I='M9B default: //judge the key and send message
q@&6&cd break;
-T=sY/O }
5"9'=LV~ for(int index=0;index<MAX_KEY;index++){
OK" fFv if(hCallWnd[index]==NULL)
.LI(2lP continue;
7CwQmVe+ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Ib(G!oO:E- {
92(P~Sdv SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
n@$("p bProcessed=TRUE;
6PyW(i(bs }
N;` jz(r }
U
ATF}x
}
-P:o ^_)g else if((lParam&0xc000ffff)==1){ //有键按下
eA_]%7+` switch(wParam)
@%"r69\ {
LsxRK5 case VK_MENU:
BZOB\Ym MaskBits|=ALTBIT;
L_sDbAT~< break;
7e:eL5f>~ case VK_CONTROL:
E_D0Nm%n MaskBits|=CTRLBIT;
hw({>cH\ break;
uk9!rE" case VK_SHIFT:
6L<QKE= MaskBits|=SHIFTBIT;
%Y-5L;MI break;
$d*PY_ default: //judge the key and send message
HChlkj'7w0 break;
d6e$'w@(\T }
aQ*?L
l for(int index=0;index<MAX_KEY;index++){
?0tm{qP if(hCallWnd[index]==NULL)
B:96E& continue;
*cP(3n3]R if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Aa+<4
R {
kx,3[qe'S SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
37b6w6{D bProcessed=TRUE;
5t,X; }
i`}!<{k }
jG`,k*eUrJ }
0at['zw if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
sSy!mtS for(int index=0;index<MAX_KEY;index++){
4Opf[3] if(hCallWnd[index]==NULL)
4I8QM&7 continue;
wvmcD% if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
$It3}?>C' SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
FQ"ED:lks //lParam的意义可看MSDN中WM_KEYDOWN部分
= N^Ec[u(l }
~gdnD4[G }
? sv[vR( }
a+^,EY return CallNextHookEx( hHook, nCode, wParam, lParam );
9@8'*a{`m }
WP{U9YF2 9aBz%* 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:
w>e+UW25Y 8Z CR9% BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
b}&.IJ&40j BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
eD|"?@cE !u;gGgQF 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:
3 MCV?"0 ${e5Ka LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
hmB`+?,z* {
3BSZz%va if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
}wZsM[NDB {
:_|Xr'n`A //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
ojyP.R SaveBmp();
D63?f\ return FALSE;
Z*n4$?%W }
qpjiQ,\:b …… //其它处理及默认处理
\]0#jI/: }
OX7a72z WmOu#5*; D?FmlDTr[ 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。
pVM1%n:# *v$j n 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。
_*cKu>,O N/eus"O; 二、编程步骤
i|rC Ga0} \D1@UyE 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";
DzIV5FG 1)3'Y2N* 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
Wuk!\<T{ E`Br# "/Bl 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;
.kTOG'K\e }`aT=_ B 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;
g'td(i[ ;9<?~S 5、 添加代码,编译运行程序。
X%5 `B2Wu G8WPXj( 三、程序代码
biZ=TI2P,L p|em_!H"SH ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
XQ2YUe]DJ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
/9,y+"0SQz #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
gnYo/q=K #if _MSC_VER > 1000
J!}\v=Rn #pragma once
~iPXn1 #endif // _MSC_VER > 1000
fWf't2H& #ifndef __AFXWIN_H__
\]g51U!' #error include 'stdafx.h' before including this file for PCH
"ZL_ #endif
+,Or^pO= #include "resource.h" // main symbols
dsOt(yNo class CHookApp : public CWinApp
_U9.u#>sV {
Z_a@,k:+[ public:
/A+5q\8G CHookApp();
/Ny#+$cfk // Overrides
7uf5w0] // ClassWizard generated virtual function overrides
bYmk5fpRG //{{AFX_VIRTUAL(CHookApp)
&fsk ESV0 public:
T7-yZSw-m virtual BOOL InitInstance();
Dw>)\\n{Kl virtual int ExitInstance();
SW5n?Qj3- //}}AFX_VIRTUAL
>[&ser //{{AFX_MSG(CHookApp)
p(cnSvg // NOTE - the ClassWizard will add and remove member functions here.
E.*gKfL // DO NOT EDIT what you see in these blocks of generated code !
S|T_<FCY //}}AFX_MSG
w}s5=>QG% DECLARE_MESSAGE_MAP()
x |gYxZ };
?M^qSo=/~ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
3.9/mztS BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
~Kl"V%> BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
~pHuh#> BOOL InitHotkey();
h/2@4XKj BOOL UnInit();
%<r}V<OeR #endif
<m0=bm{j E@6gTx* //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
W*?qOq
{ #include "stdafx.h"
3dJiu #include "hook.h"
Z;[xaP\S #include <windowsx.h>
,L
MN@G #ifdef _DEBUG
hUX8j9N> #define new DEBUG_NEW
qL
<@PC.5 #undef THIS_FILE
i3pOGa< static char THIS_FILE[] = __FILE__;
`sA xk #endif
'blMwD{0&\ #define MAX_KEY 100
AAqfp/DC #define CTRLBIT 0x04
B%`|W@v #define ALTBIT 0x02
FLZ9Rg #define SHIFTBIT 0x01
s:cJF #pragma data_seg("shareddata")
#K*p1}rf HHOOK hHook =NULL;
76]Z~^Y UINT nHookCount =0;
^=a:{["@! static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
Qn~{TZz static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
\y6Y}Cv static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
2
6
>9$S static int KeyCount =0;
&gr
T@ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
p8"C`bCf #pragma data_seg()
s>1\bio*I HINSTANCE hins;
`GlOl- void VerifyWindow();
C,%Dp0 BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
Anqt:( //{{AFX_MSG_MAP(CHookApp)
).0p\.W~ // NOTE - the ClassWizard will add and remove mapping macros here.
K7C!ZXw~ // DO NOT EDIT what you see in these blocks of generated code!
K4o']{:U //}}AFX_MSG_MAP
Vk2%yw> END_MESSAGE_MAP()
Efoy]6P\ w
`+.F;}s CHookApp::CHookApp()
qu!x#OY+ {
9I`0`o"A // TODO: add construction code here,
e
z_c; // Place all significant initialization in InitInstance
<f =<r*6 }
{=,G>p %_!0V*X* CHookApp theApp;
[k75+#' LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
=M9R~J! {
0l/7JH_@V BOOL bProcessed=FALSE;
;JgSA&'e if(HC_ACTION==nCode)
EQk omjv {
xFJT&=Af W if((lParam&0xc0000000)==0xc0000000){// Key up
wWSw0 H/ switch(wParam)
-m[ tYp,q {
xA<-'8ST case VK_MENU:
IWm@pfC+g MaskBits&=~ALTBIT;
h~qv_)F_ break;
[ w-Tf& case VK_CONTROL:
\}%_FnP0ZU MaskBits&=~CTRLBIT;
I2pE}6q break;
>o%X;U
3 case VK_SHIFT:
vbX.0f "n MaskBits&=~SHIFTBIT;
p!)PbSw# break;
2pvby`P4 default: //judge the key and send message
S4c-i2Rq break;
i3KAJ@ }
u\/TR#b for(int index=0;index<MAX_KEY;index++){
1<m.Q* if(hCallWnd[index]==NULL)
mM2I continue;
e>6W ^ ) if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
o(
mA(h {
Jr%F#/ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
8N$Xq\Da+> bProcessed=TRUE;
qrjSG%i~J7 }
j=G }
C3N1t }
YMy** else if((lParam&0xc000ffff)==1){ //Key down
M= |is*t switch(wParam)
`c|H^*RC {
m5a'Vs case VK_MENU:
B*E"yB\NV MaskBits|=ALTBIT;
>|gXE> break;
8r:T&)v case VK_CONTROL:
wDSwcNS MaskBits|=CTRLBIT;
v-^<,|vm2f break;
GMkni'pV case VK_SHIFT:
LOu9 #w" MaskBits|=SHIFTBIT;
qT:`F break;
+2k{yl default: //judge the key and send message
f}KV4'n break;
!KT.p2\ }
#;lEx'lKN for(int index=0;index<MAX_KEY;index++)
H6>t to {
A>315!d" if(hCallWnd[index]==NULL)
qsN_EMgbdn continue;
}sJ}c}b if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
4~&X]/_' {
fZS'e{V SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
R?,v:S&i7; bProcessed=TRUE;
ew~uOG+ }
>WJQxL4 }
}6 u)wF5 }
wuxOFlrg if(!bProcessed){
r+6 DlT
a for(int index=0;index<MAX_KEY;index++){
69Z`mR if(hCallWnd[index]==NULL)
7l09 continue;
rf 60' if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
{zc*yV\ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
0F6@aQ\y3 }
TEGg)\+D> }
Im};wJ& }
(lq%4h return CallNextHookEx( hHook, nCode, wParam, lParam );
j~=<O<P }
sFvYCRw
/ n=0^8QQ
BOOL InitHotkey()
u-bgk(u {
+afkpvj8 if(hHook!=NULL){
Sj*W|n\gj nHookCount++;
M0e&GR8<z> return TRUE;
kmlO}0 }
u[4h|*'"| else
[H9<JdUZ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
V$iA3)7W% if(hHook!=NULL)
/,j'Vr\" nHookCount++;
3j[<nBsn. return (hHook!=NULL);
/qq*"R }
|%rRALIY BOOL UnInit()
u*oP:!s {
EG_P^<z if(nHookCount>1){
KV'3\`v@LY nHookCount--;
.m%5Esx return TRUE;
hYA1N&yz@ }
>* F#ZZv}p BOOL unhooked = UnhookWindowsHookEx(hHook);
\l# H#~ if(unhooked==TRUE){
%kH,Rl\g nHookCount=0;
X'%BS hHook=NULL;
hY *^rY' }
6Bd:R}yZP7 return unhooked;
Uxe]T }
}dqOE-"I"n .vIRz-S BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
&$#NV@
{
vfVF^
WOd BOOL bAdded=FALSE;
)7AjRtb!/ for(int index=0;index<MAX_KEY;index++){
_W,?_"[R= if(hCallWnd[index]==0){
rJtk4hOF hCallWnd[index]=hWnd;
P.=Dd"La HotKey[index]=cKey;
4{ZVw/VP,- HotKeyMask[index]=cMask;
CSwB+yN bAdded=TRUE;
M:d|M|' KeyCount++;
mZ3Z8q}%P break;
&Ot9"Aq: }
,?%o ~ }
C nD3%% return bAdded;
]D^; Ca }
Y[m* 4
'vjU6gW BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
j~cG#t] {
gF;C% } BOOL bRemoved=FALSE;
Ly1t'{"7 for(int index=0;index<MAX_KEY;index++){
bIk4?S if(hCallWnd[index]==hWnd){
M?n}{0E4 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
mM+^v[= hCallWnd[index]=NULL;
-:Juxh HotKey[index]=0;
9`@}KnvB? HotKeyMask[index]=0;
@)z?i bRemoved=TRUE;
e;"%h%' KeyCount--;
)IIWXN2A break;
gy#G; 9p }
_?bF;R }
EU Oa8Z }
YW8Odm return bRemoved;
8)b*q\O' }
n2["Ln mO Np.<&`p! void VerifyWindow()
&s\/Uq {
q^QLNKOH" for(int i=0;i<MAX_KEY;i++){
(8~Hr?1B if(hCallWnd
!=NULL){ 3#F"UG2,_
if(!IsWindow(hCallWnd)){ /
=v1.9(
hCallWnd=NULL; C
[8='i26
HotKey=0; N]|)O]/[
HotKeyMask=0; 1vqc8lC
KeyCount--; w'mn O'%
} 78]( ZYJV
} '(3|hh)Tl
} cz$*6P<9J
} <#T#+uO
#,!/Cnqis
BOOL CHookApp::InitInstance() !Pd)
{ u1Wixjd|
AFX_MANAGE_STATE(AfxGetStaticModuleState()); y99|V39'
hins=AfxGetInstanceHandle(); Xcg+ SOB
InitHotkey(); Xupwh5G2
return CWinApp::InitInstance(); %kQ[zd^
} Dkg-y9
CzmB76zy.
int CHookApp::ExitInstance() Z22#lF\ N
{ ;`a~9uG
VerifyWindow(); iTCY $)J
UnInit(); S9qc34\^=
return CWinApp::ExitInstance(); 9;
aOUs:<
} X}&Y(kOT
>kDkv g1"
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file Cv]$w(k
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) U/\LOIs
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ d! _8+~
#if _MSC_VER > 1000 r+h$]OJ
#pragma once irGgo-x
#endif // _MSC_VER > 1000 y"w`yl{_
jF{\=&fU
class CCaptureDlg : public CDialog QGXR<