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:
?(PKeq6
y2v^-q3 一、实现方法
VQs5"K" C}X\|J 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:
#QPjkR|\ qLCR] _* #pragma data_seg("shareddata")
2|,VqVb HHOOK hHook =NULL; //钩子句柄
DqPw#<"H UINT nHookCount =0; //挂接的程序数目
!<oe=)Iz| static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
TseGXYH static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
~@!bsLSMU static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
*#2h/Q. static int KeyCount =0;
j+!v}*I![ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
9ati`-y2 #pragma data_seg()
~[
F`" )1z@ 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。
pw#-_ @L`jk+Y0vF 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:
G5!^*jf RNL9>7xV BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
)_:NLo: cKey,UCHAR cMask)
6LZCgdS{ {
H+#FSdy# BOOL bAdded=FALSE;
t7pFW^& for(int index=0;index<MAX_KEY;index++){
C^){.UGmJ if(hCallWnd[index]==0){
/}$+uBgJm hCallWnd[index]=hWnd;
hb-%_c"kq HotKey[index]=cKey;
TzZq(?V HotKeyMask[index]=cMask;
b$7 +;I; bAdded=TRUE;
IgzQr > KeyCount++;
3R/bz0 V> break;
'R)Tn!6 }
KoRV%@I }
\*da6Am return bAdded;
0_/[k*Re }
y}
'@R$ //删除热键
2!\DPX BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
JC"z&ka {
eE Kf|I BOOL bRemoved=FALSE;
K:M8h{Ua for(int index=0;index<MAX_KEY;index++){
=D(j)<9$A if(hCallWnd[index]==hWnd){
m~|40) if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
0J|3kY-n> hCallWnd[index]=NULL;
cK@wsA^4 HotKey[index]=0;
)+^+sd HotKeyMask[index]=0;
?0.NIu,,o bRemoved=TRUE;
+ 3gp%`c4 KeyCount--;
=wJX0A| break;
K"6vXv4QO }
iscz}E,Y }
`V1]k_h }
sA~]$A;DM! return bRemoved;
mq l
Z?- }
Ef\-VKh hPh-+Hb \['Cj*e k DLL中的钩子函数如下:
nTas~~Q # _1`)VS LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
)BE1Q*=
n {
'"^'MXa BOOL bProcessed=FALSE;
(:_$5&i7 if(HC_ACTION==nCode)
kM6
Qp {
NbobliC= if((lParam&0xc0000000)==0xc0000000){// 有键松开
e.> P8C<& switch(wParam)
#E[0ys1O {
9?$i? case VK_MENU:
(Z*!#}z` MaskBits&=~ALTBIT;
.`lCWeHN break;
6863xOv{T case VK_CONTROL:
1oS/`) MaskBits&=~CTRLBIT;
h8P)%p break;
M}a6Vu9 case VK_SHIFT:
?[AD=rUC MaskBits&=~SHIFTBIT;
0sqFF[i break;
>z03{=sAN default: //judge the key and send message
]]mJ']l break;
qM`}{
/i }
x:;kSh for(int index=0;index<MAX_KEY;index++){
,}PgOJZ if(hCallWnd[index]==NULL)
a#4?cEy continue;
bOB\--:] if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
_#niyW+?~ {
do%&m]#; SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
IPk4
;, bProcessed=TRUE;
.H|-_~Yx| }
*|0 -~u%q }
j.Hf/vi`z }
+0&/g&a\R else if((lParam&0xc000ffff)==1){ //有键按下
osRy e3 switch(wParam)
2T35{Q!=F {
eavV?\uV% case VK_MENU:
. vV|hSc MaskBits|=ALTBIT;
|=w@H]r break;
f 2.HF@ case VK_CONTROL:
\zkg MaskBits|=CTRLBIT;
@- xjfC\d break;
^y::jK case VK_SHIFT:
G2D$aSh MaskBits|=SHIFTBIT;
,hVli/
break;
%A`+WYeuX default: //judge the key and send message
paK2xX8E break;
l;Wj] }
+2{Lh7Ks for(int index=0;index<MAX_KEY;index++){
vQCy\Gi if(hCallWnd[index]==NULL)
u[YGm:} continue;
gJXaPJA{ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
UfGkTwoo= {
\~W'v3:W SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
f8~_E bProcessed=TRUE;
@5FQX }
u_enqC3 }
!a`&O-ye }
Sc0w.5m6 if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
HtFDlvdy] for(int index=0;index<MAX_KEY;index++){
0S"MC9beg if(hCallWnd[index]==NULL)
;I}fBZ3
continue;
b=vkiO`2 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
6Oq7#3] SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Vksuu@cch //lParam的意义可看MSDN中WM_KEYDOWN部分
mt
.sucT }
vN:Ng }
s<Ziegmw|g }
hb$Ce'}N return CallNextHookEx( hHook, nCode, wParam, lParam );
;uJMG }
?4 ,T}@P j%kncGS 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:
h{Y",7]! e+WNk
2 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
?< +WG/(d BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
>Tgv11[ 5!
{D! 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:
4Z*/WsCv 4x34u}l LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
]^E?;1$f? {
G{}VPcrbC if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
0J9x9j`&j {
P:c w|Q //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
M3\AY30L SaveBmp();
54T`OE
= return FALSE;
/m1\ iM\ }
zX[U~. …… //其它处理及默认处理
';CNGv - }
0mE 0 j pBHRa?Y5 x5Bk/e' 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。
3og.y+.=U. ZK,G v 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。
6P3*Z oJ^P(] dw 二、编程步骤
X?O[r3< @d'j zs 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";
H_a[)DT zhQJy?>'m 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
7!1S)dup 3]Ct6 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;
(PLUFT ?<!| 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;
oH@78D0A |yCMt:Hk 5、 添加代码,编译运行程序。
6k%f e~OpofJNb 三、程序代码
2y4bwi *dQSw)R ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
ES[G #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
f*Hr^b}`8 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
z{
dEC % #if _MSC_VER > 1000
&C}*w2]0S #pragma once
=_CzH(=f# #endif // _MSC_VER > 1000
"oyo#-5z #ifndef __AFXWIN_H__
wwqEl( #error include 'stdafx.h' before including this file for PCH
Wtnfa{gP% #endif
F?0Ykjh3 #include "resource.h" // main symbols
OUnA;_ class CHookApp : public CWinApp
pa+hL,w{6 {
:OT& public:
M\j.8jG CHookApp();
_ q"Gix // Overrides
c<~H(k'+c // ClassWizard generated virtual function overrides
6tZI["\ //{{AFX_VIRTUAL(CHookApp)
!
nx{
X public:
0GL M(JmK virtual BOOL InitInstance();
Gv&V|7-f0 virtual int ExitInstance();
Eci\a] //}}AFX_VIRTUAL
P55fL-vo|} //{{AFX_MSG(CHookApp)
>P(.:_^p // NOTE - the ClassWizard will add and remove member functions here.
kh<2BOV // DO NOT EDIT what you see in these blocks of generated code !
F4QVAOM]U //}}AFX_MSG
(3e2c DECLARE_MESSAGE_MAP()
kJU2C=m@e2 };
" bG2: LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
PT
~D",k BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
G@0&8 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
;uW FHc5@B BOOL InitHotkey();
gYj'(jB BOOL UnInit();
hH.G#-JO #endif
BtZ yn7a GgU/!@ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
g(g& TO #include "stdafx.h"
[g,}gyeS( #include "hook.h"
!D6]JPX #include <windowsx.h>
qs6aB0ln #ifdef _DEBUG
3|7QUld #define new DEBUG_NEW
%<5'=t'|-U #undef THIS_FILE
|Tw~@kT@ static char THIS_FILE[] = __FILE__;
AA_%<zK #endif
7)m9"InDI #define MAX_KEY 100
b>k y #define CTRLBIT 0x04
M|-)GvR$J #define ALTBIT 0x02
N`i/mP #define SHIFTBIT 0x01
fA-7VdR`R #pragma data_seg("shareddata")
KoY F] HHOOK hHook =NULL;
pAEx#ck UINT nHookCount =0;
~[: 2I static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
t^HRgY'NjM static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
*j=%
# static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
GbyJ: static int KeyCount =0;
Ac6=(B static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
%y@AA>x! #pragma data_seg()
g0H[*"hj HINSTANCE hins;
'qi}|I void VerifyWindow();
P>L +t`' BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
58K5ZZG //{{AFX_MSG_MAP(CHookApp)
RSds8\tk // NOTE - the ClassWizard will add and remove mapping macros here.
)jj0^f1!j // DO NOT EDIT what you see in these blocks of generated code!
J,G
lIv.A //}}AFX_MSG_MAP
QJNFA}*> END_MESSAGE_MAP()
mOSv9w#, V~bD)?M CHookApp::CHookApp()
X]=t> {
;<5q]/IHK // TODO: add construction code here,
R]dg_Da // Place all significant initialization in InitInstance
d-m7}2c }
l:%GH 0YzpZW"+ CHookApp theApp;
V)^+?B)T LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
+p^u^a {
neh(<> BOOL bProcessed=FALSE;
"b[5]Y{
U if(HC_ACTION==nCode)
l,
wp4Ll {
!wNO8;( if((lParam&0xc0000000)==0xc0000000){// Key up
l2d{ 73h switch(wParam)
l0]
EX>"E {
4 :=]<sc, case VK_MENU:
a?.=V MaskBits&=~ALTBIT;
@;kSx":b break;
|}1dFp case VK_CONTROL:
hph4 `{T MaskBits&=~CTRLBIT;
h![#;>( break;
f?b"i A(6 case VK_SHIFT:
P2!C|SLK MaskBits&=~SHIFTBIT;
zX~MC?,W1 break;
l,:F default: //judge the key and send message
Q&&@v4L break;
m*;ERK }
v:p} B$ for(int index=0;index<MAX_KEY;index++){
g>sSS8RO if(hCallWnd[index]==NULL)
z2c6T.1M continue;
z~Q)/d,Ac if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
*A< 5*Db:F {
ckn~#UE= SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
5uf a bProcessed=TRUE;
DMS!a$4
}
*H122njH+T }
F/Pep?' }
_U0f=m else if((lParam&0xc000ffff)==1){ //Key down
1}37Q&2 switch(wParam)
>+waX"e {
cAy3^{3: case VK_MENU:
_6Ha MaskBits|=ALTBIT;
9kojLqCT break;
7KPwQ?SjT case VK_CONTROL:
3F0 N^)@ MaskBits|=CTRLBIT;
V1?]|HTQcT break;
kLY^! case VK_SHIFT:
ca}2TT&t MaskBits|=SHIFTBIT;
-+5>|N# break;
Tr|JYLwF default: //judge the key and send message
FqifriLN break;
i?gSC<a }
ExM,g' 7 for(int index=0;index<MAX_KEY;index++)
^GX)Z~ {
{U1m.30n if(hCallWnd[index]==NULL)
kl,3IKHa continue;
nd(S3rct& if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
cFv8 Od {
<X5fUU"+U SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
8] ikygt" bProcessed=TRUE;
KU;9}!# }
gJhiGYx }
2[CdZ(k]5 }
>Se,;cB'/] if(!bProcessed){
&0f,~ /%Z for(int index=0;index<MAX_KEY;index++){
`"~%bS if(hCallWnd[index]==NULL)
N<-Gk6`C/ continue;
`lPfb[b if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Q,9oKg SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
s{" 2L{,$ }
xm@_IL&P }
s@DLt+ O5 }
N&pCx& return CallNextHookEx( hHook, nCode, wParam, lParam );
!a<ng&H^U }
6R5Qy]]E LK"69Qx?5q BOOL InitHotkey()
7)k\{&+P {
-(#iIgmP if(hHook!=NULL){
#,.Hr#3nI nHookCount++;
]fD}
^s3G return TRUE;
h}EPnC} }
@R
6@]Dm else
_l]fkk[T hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
B]$GSEB if(hHook!=NULL)
N !|wo: nHookCount++;
`p7=t)5k return (hHook!=NULL);
A4ygW: }
""D 4s BOOL UnInit()
&w~d_</ {
L^Fy#p if(nHookCount>1){
h*Pc=/p nHookCount--;
6DWgl$[[ return TRUE;
#u
+ v_ }
7`YEH2 BOOL unhooked = UnhookWindowsHookEx(hHook);
,u
g@f-T if(unhooked==TRUE){
}{<
'8J.R nHookCount=0;
_7)n(1h[3b hHook=NULL;
z"4~P3>{g }
orvp*F{7[H return unhooked;
;ZG\p TCA }
&=k,?TJO> G/mXq-
BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
`V3Fx{
{
4NIRmDEd BOOL bAdded=FALSE;
S@ f9c for(int index=0;index<MAX_KEY;index++){
{vO9ptR; if(hCallWnd[index]==0){
RAK-UN hCallWnd[index]=hWnd;
+&"zU GTIc HotKey[index]=cKey;
}-3mPy(*% HotKeyMask[index]=cMask;
Uv~QUL3> bAdded=TRUE;
T"}vAG( .O KeyCount++;
|B2+{@R break;
Z*2Vpnqh\ }
TvQo? }
qcGK2Qx return bAdded;
ff1c/c/ }
',4iFuY K!]/(V(} BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
*r% c {
6B
?twh) BOOL bRemoved=FALSE;
<V6VMYXY4 for(int index=0;index<MAX_KEY;index++){
uL/m u< if(hCallWnd[index]==hWnd){
FjI`uP if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
D{~fDRR hCallWnd[index]=NULL;
$"&{aa HotKey[index]=0;
M[112%[+4 HotKeyMask[index]=0;
`I5wV/%ib bRemoved=TRUE;
mS~kJy_- KeyCount--;
:Qf '2.h) break;
}XM(:|8J, }
`%Al>u5 }
@[i4^ }
Q( {
r@*g return bRemoved;
VgC2+APg }
xLZG:^(I :'&brp3ii= void VerifyWindow()
B i<Q=x'Z; {
JOim3(5?s for(int i=0;i<MAX_KEY;i++){
usL*
x9i if(hCallWnd
!=NULL){
{ Z5nGG
if(!IsWindow(hCallWnd)){ ye? 'Ze
hCallWnd=NULL; A4<Uu~
HotKey=0; 4^OY
C
HotKeyMask=0; TSWM
|#u':
KeyCount--; YNj`W1
} =;&yd';k
} @)&=%
} ;<2G
} e?ly H
EJ:%}HhA
BOOL CHookApp::InitInstance() jc f #6
{ ]Y8<`;8/
AFX_MANAGE_STATE(AfxGetStaticModuleState()); #@~+HC=
hins=AfxGetInstanceHandle(); _ T):G6C8
InitHotkey(); Zt.|oYH$
return CWinApp::InitInstance(); o/Q;f@
} s '\Uap
-f>%+<