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:
1M5 -pZ[D
bkQ3c-C< 一、实现方法
uDG+SdyN@ SE `l(-tL 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:
(O5)wej `.BR=['O #pragma data_seg("shareddata")
UmP'L! HHOOK hHook =NULL; //钩子句柄
2R@%Y/ UINT nHookCount =0; //挂接的程序数目
9U<Hf32 static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
%xg"Q| static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
?ApRJm:T static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
mvTb~) static int KeyCount =0;
F,}s$v static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
[%8@DC' #pragma data_seg()
'V!kL,
9ES xb^Mo.\[ 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
=HE
m) %?tq;~|]Q DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
{yq8<? U</+ .$b BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
[&VxaJ("3 cKey,UCHAR cMask)
lizTRVBE {
!WKk=ysFS BOOL bAdded=FALSE;
(K
#A for(int index=0;index<MAX_KEY;index++){
f!g<3X{= if(hCallWnd[index]==0){
rihlae5Kz hCallWnd[index]=hWnd;
tV`&-H HotKey[index]=cKey;
`SOhG?Zo HotKeyMask[index]=cMask;
LM1b I4 bAdded=TRUE;
'j79GC0 KeyCount++;
%W;u}` break;
c^S&F9/U* }
Es;;t83p }
\3^Pjx return bAdded;
I'IB_YRL4 }
!<Z{@7oH //删除热键
a$+#V=bA BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
@d)a~[pm {
oh&Y<d0 BOOL bRemoved=FALSE;
?)cJZ>$!w for(int index=0;index<MAX_KEY;index++){
,L%p if(hCallWnd[index]==hWnd){
@hT;Bo2G] if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
_i@x@:_l hCallWnd[index]=NULL;
|R~;&x: HotKey[index]=0;
U42\.V0 HotKeyMask[index]=0;
1g i}H) bRemoved=TRUE;
q<XcOc5 KeyCount--;
7Po/_% break;
s/S+ ec3 }
L?f qcW{ }
1URsHV!xcM }
bOXh|u_3i return bRemoved;
ZjD2u8e }
@3 "DBJ cEi<}9r tc/ jY]'32 DLL中的钩子函数如下:
dofR)"<p,^ Mf7E72{D LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
>sV Bj(f {
ngqUH BOOL bProcessed=FALSE;
liG~y| if(HC_ACTION==nCode)
I"V3+2e {
GTFl}t if((lParam&0xc0000000)==0xc0000000){// 有键松开
UCF[oO>v switch(wParam)
rqC1 {
lt%-m@#/ case VK_MENU:
wea\8[U3" MaskBits&=~ALTBIT;
'%O\E{h break;
&
=sa yP case VK_CONTROL:
!:J<pWN" MaskBits&=~CTRLBIT;
qS82/e)7 break;
s=j O;K$ case VK_SHIFT:
`w=!o.1 MaskBits&=~SHIFTBIT;
riEqW}{ break;
)`RZkCe default: //judge the key and send message
Ap,q
`S break;
K!b>TICa: }
:+A;TV for(int index=0;index<MAX_KEY;index++){
<w11nB) if(hCallWnd[index]==NULL)
\]GGVI;u continue;
qid1b
b if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
"2K|#,%N {
V,'FlU SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
%>NRna bProcessed=TRUE;
ndt8=6p
}
e)og4 }
% NwoU%q }
Ug` else if((lParam&0xc000ffff)==1){ //有键按下
%J3lK]bv( switch(wParam)
Nuo<` 6mV@ {
$YR{f[+L
w case VK_MENU:
oG9SO^v_ MaskBits|=ALTBIT;
D2-O7e break;
<v-92? case VK_CONTROL:
"lb\c MaskBits|=CTRLBIT;
6!o/~I# break;
h@/>?Va case VK_SHIFT:
$pJ3xp& MaskBits|=SHIFTBIT;
{Bv`i8e break;
kjfxjAS=m default: //judge the key and send message
3~8AcX@ break;
ri;r7Y9V9` }
'4Y*-!9 for(int index=0;index<MAX_KEY;index++){
|W/Hi^YE2 if(hCallWnd[index]==NULL)
n7'<3t continue;
oPE.gn_$ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
/iTH0@Kw; {
N}1-2 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
.y(@Y6hO bProcessed=TRUE;
^W{eO@ }
Is~yVB02 }
@~Rk^/0 }
?##y`.+O if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
J]_)gb'1BR for(int index=0;index<MAX_KEY;index++){
K
oL%}u& if(hCallWnd[index]==NULL)
0c{Gr 0[> continue;
vV2o[\o^ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
%hrsE5k^, SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
RH1U_gp4 ] //lParam的意义可看MSDN中WM_KEYDOWN部分
KN|'|2/| }
9yp^zL }
Ez wF`3RjK }
aw;{<?* return CallNextHookEx( hHook, nCode, wParam, lParam );
ZW`HDrP` }
Oym]&SrbS >4Fdxa 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:
!WDn7j'A 7E@$}&E BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
W'8J<VBD BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
;%lJD"yF HXz iDnj 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{c5dQ
il<gjlyR]L LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
)E_!rR {
_p?I{1O if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
3<yCe%I: {
ggzAU6J //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
P'KY.TjWb SaveBmp();
vsxvHot= return FALSE;
"1E?3PFJ
}
3" 8t)s …… //其它处理及默认处理
jAsh
}
vQE` c@^{ GWVEIZ qsQ]M^@> 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。
F\I5fNs@ $XtV8 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。
GXGN;,7EV dICnB:SSB 二、编程步骤
)I^)*(} zV9
= 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";
Ji)%Y5F P DNt4=C 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
vWZ>Hf]`L _
+u sn. 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;
K7YT0cG 9G=A)j 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;
<5C=i:6% 9}IVNZc 5、 添加代码,编译运行程序。
fLf#2EA jauc*347 三、程序代码
g#pIMA#/ +A;n*DF2 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
) >-D={ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
K]lb8q}Z~ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
_&6juBb #if _MSC_VER > 1000
`XFX`1 #pragma once
$u(M 4(} #endif // _MSC_VER > 1000
W`
6"!V #ifndef __AFXWIN_H__
y81#UD9[ #error include 'stdafx.h' before including this file for PCH
6tCV{pgm #endif
g0[<9.ke #include "resource.h" // main symbols
pb $ An<P class CHookApp : public CWinApp
lUy*549, {
IX > j8z[ public:
96^1Ivd CHookApp();
`*.r'k2R // Overrides
w%!k?t,*] // ClassWizard generated virtual function overrides
.je~qo) //{{AFX_VIRTUAL(CHookApp)
5+#?7J1 public:
10a=YG virtual BOOL InitInstance();
"1=.5:yG virtual int ExitInstance();
D~t"9Z\ //}}AFX_VIRTUAL
E#WjoIk //{{AFX_MSG(CHookApp)
3(XHF3q // NOTE - the ClassWizard will add and remove member functions here.
?kG#qt]Q5 // DO NOT EDIT what you see in these blocks of generated code !
&eLQ;<qO*| //}}AFX_MSG
ZKiL-^dob DECLARE_MESSAGE_MAP()
N69eIdl };
"m<eHz]D LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
FN8=YUYK% BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
D:S6Mu BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
j.G.Mx" BOOL InitHotkey();
>8.v.;` BOOL UnInit();
;8
/+wBnm #endif
+)''l `i_L?C7 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
h<!khWFS #include "stdafx.h"
e2_r0I^C #include "hook.h"
%$!R] B) #include <windowsx.h>
9 Le/'o vq #ifdef _DEBUG
v\r7.l:hf #define new DEBUG_NEW
8kn]_6:3i #undef THIS_FILE
HCn]# static char THIS_FILE[] = __FILE__;
`eA&C4oFOO #endif
u:qD*zOq #define MAX_KEY 100
~L Bq5a #define CTRLBIT 0x04
VAG+y/q #define ALTBIT 0x02
r5fz6" #define SHIFTBIT 0x01
:p*ojl| #pragma data_seg("shareddata")
dcc%G7w HHOOK hHook =NULL;
>(1_Dn\ UINT nHookCount =0;
^~*[~ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
OL6xMToP static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
#xJGuYdv static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
R)DNFc: static int KeyCount =0;
8 MACbLY static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
WPh |~]by< #pragma data_seg()
m}'t'l4 c HINSTANCE hins;
UHsrZgIRYT void VerifyWindow();
o )}< BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
ytcG6WN3 //{{AFX_MSG_MAP(CHookApp)
el*pYI // NOTE - the ClassWizard will add and remove mapping macros here.
W>
-E.#!_ // DO NOT EDIT what you see in these blocks of generated code!
e*'|iuDrY //}}AFX_MSG_MAP
")[Q4H;V END_MESSAGE_MAP()
fuIv,lDA \Z7([G h CHookApp::CHookApp()
o\:f9JL {
=-s20mdj // TODO: add construction code here,
V?L$ys // Place all significant initialization in InitInstance
b&V]|Z( }
&j~|3 .]sIoB-54 CHookApp theApp;
\i;~~;D LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
1\.zOq# {
P.H/H04+ BOOL bProcessed=FALSE;
TF iM[ if(HC_ACTION==nCode)
&s}@7htE {
%(7wZ0Z if((lParam&0xc0000000)==0xc0000000){// Key up
<:yq~? switch(wParam)
6^z\;,p {
9'*ZEl^?D case VK_MENU:
BC0c c[x MaskBits&=~ALTBIT;
^TCJh^4na break;
=rO>b{,hs case VK_CONTROL:
8KELN(o$ 7 MaskBits&=~CTRLBIT;
R_*D7|v break;
2;(iTPz + case VK_SHIFT:
'V9aB5O&
MaskBits&=~SHIFTBIT;
LU IT=+ break;
"i<3}6/* default: //judge the key and send message
W<hdb!bE break;
n#L2cv~Aj" }
6UAxl3-\ for(int index=0;index<MAX_KEY;index++){
O> ^~SO if(hCallWnd[index]==NULL)
/E
yg*# continue;
yc4f\0B/ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
V7'x?
pt {
W
me1w\0 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
~U*N'>'=) bProcessed=TRUE;
GvtI-\h] }
it|:P }
1YD.jU^;HD }
+PXfr~ 4 else if((lParam&0xc000ffff)==1){ //Key down
c&?H8G)x switch(wParam)
H_f2:Za {
*>*/| case VK_MENU:
$
5-2cL MaskBits|=ALTBIT;
[)6E)E`_e break;
Z q>.;> case VK_CONTROL:
2DqHqq9m MaskBits|=CTRLBIT;
M~Dc5\T break;
G6F['g); case VK_SHIFT:
[gr[0aG Bc MaskBits|=SHIFTBIT;
Hwc8i"{9y\ break;
N6
(w<b default: //judge the key and send message
>@e%,z break;
@!NHeH=pR }
a}7KpKCD for(int index=0;index<MAX_KEY;index++)
x(N}^Hu {
^52R`{ if(hCallWnd[index]==NULL)
P2RL\`<" continue;
oOSyOD if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
0]0M>vx
u {
D)cwttH SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
< io8
b|A bProcessed=TRUE;
%D0Ws9:| }
+Z(VWu6 }
M
+q7h+HP }
-^Va]Lk if(!bProcessed){
^S2}0Nf for(int index=0;index<MAX_KEY;index++){
1c~#]6[ if(hCallWnd[index]==NULL)
Q</HFpE continue;
ZP/=R<< if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
4c@F.I SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
w~?eX/; }
TL:RB)- < }
,.F+x} }
$oj<yH<i return CallNextHookEx( hHook, nCode, wParam, lParam );
(W/UR9x)|d }
~ZN9 E-uL p}X87Zq BOOL InitHotkey()
)
hB*Hjh {
hIr^"kVK if(hHook!=NULL){
<u/({SZ& nHookCount++;
8[IifF1M=& return TRUE;
9DE)5/c`v }
=R`2 m else
C}E
ea~ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
?,>y`Qf*| if(hHook!=NULL)
ZA@"uqa 6b nHookCount++;
K#m o+n5-; return (hHook!=NULL);
El}z^e }
th|Q NG BOOL UnInit()
+-V?3fQ {
QV1%Zou if(nHookCount>1){
>@iV!! nHookCount--;
j
pV return TRUE;
.C?g nOq }
-3Hq 1 BOOL unhooked = UnhookWindowsHookEx(hHook);
&T}e93] if(unhooked==TRUE){
zf#&3K 'k nHookCount=0;
]0E- lD0J hHook=NULL;
4ebGAg ?_ }
!I&Sy]G return unhooked;
(^\i(cfu6Q }
%R>MSSjvr RL9P:]
^ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
VTa8.(i6v {
$<PVzW,$o BOOL bAdded=FALSE;
)cXc"aj@s for(int index=0;index<MAX_KEY;index++){
K2Zy6lGOZ if(hCallWnd[index]==0){
x]T;W&s hCallWnd[index]=hWnd;
~qH@Kz\% HotKey[index]=cKey;
\
3N#% HotKeyMask[index]=cMask;
Fsh-a7Qp bAdded=TRUE;
Fjb[Ev KeyCount++;
U>XGJQ<NS break;
$4pW#4/4 }
0kfw8Lon }
[U0c return bAdded;
ok'1 }
B%/Pn
2 xm5D$m3# BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
\=~Ap#Mpc4 {
M#m7g4*L ! BOOL bRemoved=FALSE;
#S)*MT4ke for(int index=0;index<MAX_KEY;index++){
nFSa~M if(hCallWnd[index]==hWnd){
wDk[)9#A if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
wwz<c5 hCallWnd[index]=NULL;
HS7!O HotKey[index]=0;
Lif mYn[ HotKeyMask[index]=0;
`Ii>wb bRemoved=TRUE;
;z#9>99rH KeyCount--;
qMkP/BjV break;
x4K5 }
FKP^f\!M }
4=Zlsp }
_1~Sj* return bRemoved;
` {p5SYj }
M}>q> JQqDUd void VerifyWindow()
frt?*|: {
=zKp(_[D for(int i=0;i<MAX_KEY;i++){
x$E
l7=. if(hCallWnd
!=NULL){ pFuQ!7Uk
if(!IsWindow(hCallWnd)){ "M
tQj}
hCallWnd=NULL; >*MB_m2|
HotKey=0; 6dh PqL
HotKeyMask=0; Velmq'n
KeyCount--; b8Qm4 b?:4
} ~oI49Q&{
} /zWWUl`:
} }|d:(*
} v|xlI4
VO9<:R
BOOL CHookApp::InitInstance() T7v8}_"-
{ t65!2G"<
AFX_MANAGE_STATE(AfxGetStaticModuleState()); \ gN) GR
hins=AfxGetInstanceHandle(); c?d#Bj ?
InitHotkey(); TJ<PT
return CWinApp::InitInstance(); E$T#o{pai
} jL# ak V
*=8)]_=f
int CHookApp::ExitInstance() +2?[=g4;}
{ ?/\;K1c p
VerifyWindow(); .&ZVy{uP
UnInit(); {:Q2Itsy
return CWinApp::ExitInstance(); |Yx8Ez
} :1iw_GhJf
O]>Or3oO
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file [|YMnV<B
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) gDv]n^&