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:
~H[
V$y6=Q<c 一、实现方法
ao4"=My*G !N\<QRb\q 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
R+'$V$g\X T&M*sydA #pragma data_seg("shareddata")
[E9V#J89 HHOOK hHook =NULL; //钩子句柄
kq;1Ax0{ UINT nHookCount =0; //挂接的程序数目
5a$Q}!6E.Y static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
UDjmXQ2, static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
W62 $ HI static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
(IlHg^" static int KeyCount =0;
#nK38W# static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
fkLI$Cl #pragma data_seg()
C$"N)6%q RJpH1XQ
j 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。
T:v.]0l~ 4@2<dw|*h 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:
=mVWfFL jZjWz1+ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
6`KR cKey,UCHAR cMask)
12 8aJ {
?q^o|Y/ BOOL bAdded=FALSE;
4Zz%vY for(int index=0;index<MAX_KEY;index++){
fL0dy[Ch@ if(hCallWnd[index]==0){
%bu$t, hCallWnd[index]=hWnd;
{e'P*j HotKey[index]=cKey;
F$L2bgQR?' HotKeyMask[index]=cMask;
mS\gh)<h bAdded=TRUE;
D4@).% KeyCount++;
2C6o?*RjyY break;
qPI\Y3ZU }
0bG[pp$[ }
g mdJ8$ return bAdded;
/+V}. }
mu#IF'|b //删除热键
M =/+q BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
pZE}<EX {
[b2KBww\ BOOL bRemoved=FALSE;
[Rj_p&'
for(int index=0;index<MAX_KEY;index++){
yL2sce[ if(hCallWnd[index]==hWnd){
'99rXw if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
%bN+Y' hCallWnd[index]=NULL;
(Q]Ww_r~ HotKey[index]=0;
?-Qq\D^+ HotKeyMask[index]=0;
;[qA?<GJ bRemoved=TRUE;
1bz%O2U-( KeyCount--;
?l> <?i break;
u=6LPwiI }
VQ R
E] }
&@v&5EXOw }
[Qw BSq8) return bRemoved;
]$7yB3S,B }
5cUz^ > =x
xN3Ay kTW[) DLL中的钩子函数如下:
^)nIf)9}7 C8Oh]JF4d LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
B>;`$- {
XLgp.w; BOOL bProcessed=FALSE;
APJVD- if(HC_ACTION==nCode)
gLss2i.r {
c{"qrwLA if((lParam&0xc0000000)==0xc0000000){// 有键松开
yC:C switch(wParam)
@$7'{* {
Op_(10| case VK_MENU:
b Y2:g ) MaskBits&=~ALTBIT;
f-BPT2U+ break;
shZEE2Dr case VK_CONTROL:
g=na3^PL6 MaskBits&=~CTRLBIT;
<~bvfA= break;
{9XN\v=$"* case VK_SHIFT:
[*K.9}+G_ MaskBits&=~SHIFTBIT;
h( DmSW break;
)i^S:2 default: //judge the key and send message
Krd0Gc~\|
break;
="('
#o }
@@3%lr71
for(int index=0;index<MAX_KEY;index++){
O +u?Y if(hCallWnd[index]==NULL)
S}3? continue;
7PbwCRg if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
4*&2D-8<K {
'j9x(T1M1 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
=/+f3 bProcessed=TRUE;
tiPZ.a~k }
gX~lYdA }
Tl
L,dPM }
Gm[XnUR7V else if((lParam&0xc000ffff)==1){ //有键按下
nC}Y+_wo0 switch(wParam)
Y~B-dx'V {
ew&"n2r case VK_MENU:
f~?kx41dq MaskBits|=ALTBIT;
,R}9n@JI^Y break;
f<;eNN case VK_CONTROL:
P>hR${KE MaskBits|=CTRLBIT;
0V+v)\4FE break;
48)D%867.; case VK_SHIFT:
b"y4-KV MaskBits|=SHIFTBIT;
7 &iav2q break;
hO2W!68 default: //judge the key and send message
:{ Lihe~\ break;
I`nC\%g }
PU-L,]K for(int index=0;index<MAX_KEY;index++){
g~XR#vl$ if(hCallWnd[index]==NULL)
AEd9H
+I continue;
nP0rg if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
|`' WEe2 {
_ZE&W SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Ud_0{%@ bProcessed=TRUE;
M9.FtQhK/ }
Uka(Vr: }
"}2I0tM }
U
U3o (Yq if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
oxug
for(int index=0;index<MAX_KEY;index++){
= Atyy if(hCallWnd[index]==NULL)
k54b@U52 h continue;
Lb~'
I=9D if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
6$t+Q~2G! SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
r`sG! //lParam的意义可看MSDN中WM_KEYDOWN部分
23X-h#w }
A]MX^eY }
aWY#gI{ }
:464~tHI[` return CallNextHookEx( hHook, nCode, wParam, lParam );
jEm=A8q }
sC_doh_M TiKfIv 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
B.}j1Bb G[]h1f! BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
tlgg~MViS BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
71Y3.1+ U:gvK8n 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
QzY5S0 (8(P12l LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
>6|Xvtf {
jpZ 7p; if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
x??H%'rP {
G@U}4'V9 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
:ay`Id_tm SaveBmp();
-kb;h F}. return FALSE;
c1<jY~U }
vofBS …… //其它处理及默认处理
<1<0 odB }
tcD5"ALJ Kc`#~-`,( %-an\.a. 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
cRSgP{hy <FwAV=}6p 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
LAuaowE\v !!6g<S7) 二、编程步骤
fz%e?@>q Hi&bNM>?O 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
o),@I#fM Mlo:\ST| 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
c
LfPSA =-!B4G$ 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;
*rC%nmJwk! {?X9juc/# 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;
_r`(P#Hy } A}Vd:# 5、 添加代码,编译运行程序。
|9mGX9q fwSI"cfM 三、程序代码
[pz1f!Wn ^geY Ay ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
"F?p Y@4 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
:!fU+2$`^( #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
aL/7xa #if _MSC_VER > 1000
>viLvDng #pragma once
hn e}G._b #endif // _MSC_VER > 1000
Hm_&``=' #ifndef __AFXWIN_H__
L/,M@1@R #error include 'stdafx.h' before including this file for PCH
jtPHk*>^wu #endif
*-@@t+3 #include "resource.h" // main symbols
2 '8I/>- class CHookApp : public CWinApp
-_f-j {
G.qjw]Llf public:
sX(rJLbD CHookApp();
)Hqn // Overrides
WISeP\:^ // ClassWizard generated virtual function overrides
LF!S`|FF //{{AFX_VIRTUAL(CHookApp)
Zc=#Y public:
>"D0vj virtual BOOL InitInstance();
<4*)J9V^s= virtual int ExitInstance();
tA-p!#V<k1 //}}AFX_VIRTUAL
a'7RzN ,] //{{AFX_MSG(CHookApp)
[UB]vPXm$ // NOTE - the ClassWizard will add and remove member functions here.
D/tFN+|P // DO NOT EDIT what you see in these blocks of generated code !
bJL ,pe+u //}}AFX_MSG
r?WOum DECLARE_MESSAGE_MAP()
df9$k0Fx };
V.w!]{xm LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
B`|H}KU BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
B{NGrC`5) BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
S,#UA%V" BOOL InitHotkey();
!H`uN
BOOL UnInit();
uD4$<rSHb #endif
ExSy/^4f y&2O)z!B //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
y{QF#&lW #include "stdafx.h"
hFDo{yI #include "hook.h"
} BnPNc[I #include <windowsx.h>
m"~),QwF9 #ifdef _DEBUG
fUB+9G(Bx #define new DEBUG_NEW
%F] :nk` #undef THIS_FILE
-to 3I static char THIS_FILE[] = __FILE__;
7G23D #endif
n<MreKixE #define MAX_KEY 100
X1GM\*BE #define CTRLBIT 0x04
0zXF{5Up #define ALTBIT 0x02
_Zbgmasb #define SHIFTBIT 0x01
.Yxf0y?uv #pragma data_seg("shareddata")
a`zw5 HHOOK hHook =NULL;
{_X&{dZLX UINT nHookCount =0;
xBAASy static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
.q9i10C static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
T :X A static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
]D|Hq4ug static int KeyCount =0;
3 ~\S] static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
;r3|EA35 #pragma data_seg()
1)ZdkTF@H HINSTANCE hins;
:tBZu%N/N void VerifyWindow();
F6-U{+KU$! BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
Nrk/_0^ //{{AFX_MSG_MAP(CHookApp)
BY??X= // NOTE - the ClassWizard will add and remove mapping macros here.
{&.?u1C.\ // DO NOT EDIT what you see in these blocks of generated code!
S{c;n*xf //}}AFX_MSG_MAP
&BQ%df<y\ END_MESSAGE_MAP()
TS;?>J- Dhp|%_> CHookApp::CHookApp()
WfkP {
zNJ-JIo% // TODO: add construction code here,
BI0 A0 // Place all significant initialization in InitInstance
u
YJL^I8M' }
^0T[V-PgiD T>pz?e^5& CHookApp theApp;
Zcxj.F(, LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
VtJyE} {
D^\2a;[AxA BOOL bProcessed=FALSE;
iU
a `< if(HC_ACTION==nCode)
ob"yz } {
hS+R/7 if((lParam&0xc0000000)==0xc0000000){// Key up
xsSX~` switch(wParam)
^ l9NF {
Q1?0]5 case VK_MENU:
K^+}__;] MaskBits&=~ALTBIT;
dX5|A_Ex break;
9U~sRj=D case VK_CONTROL:
bdkxCt MaskBits&=~CTRLBIT;
lF.yQ break;
T&~7*j(|e case VK_SHIFT:
I6Mr[#* MaskBits&=~SHIFTBIT;
>PMLjXK break;
u3@v default: //judge the key and send message
_f@,
>l break;
zV"oB9\9O }
k?'<f for(int index=0;index<MAX_KEY;index++){
O\KSPy7YQ if(hCallWnd[index]==NULL)
[p[C45d=< continue;
y<A%& if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
rE&+fSBD {
Ig M_l= SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
O)Mf/P' bProcessed=TRUE;
N"q C-h }
dw]wQ\4B }
hCKx%&[^7 }
zS+_6s else if((lParam&0xc000ffff)==1){ //Key down
V_-{TGKX switch(wParam)
d T*8I0\+ {
y:3d`E4Xw case VK_MENU:
EU"J'? MaskBits|=ALTBIT;
-*r]9f6x break;
.&Ok53]b case VK_CONTROL:
#\)tz z MaskBits|=CTRLBIT;
r9d dVD break;
$ZOKB9QccC case VK_SHIFT:
p>@S61
&
[ MaskBits|=SHIFTBIT;
OnKPD=< break;
j |tu|Q default: //judge the key and send message
=!cI@TI break;
qm&Z_6Pw }
Ft)Z'&L
for(int index=0;index<MAX_KEY;index++)
6b8@6;&LI {
\O7Vo<B&D if(hCallWnd[index]==NULL)
K9J"Q4pEC continue;
njy^<7; if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Iu -CXc {
1xkU;no SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Q$(0Nx< bProcessed=TRUE;
*!gj$GK@% }
X}5aE4K/ }
b:iZ.I }
Q:x:k+O- if(!bProcessed){
&z\]A,=Tc for(int index=0;index<MAX_KEY;index++){
yT>t[t60/S if(hCallWnd[index]==NULL)
v0dFP0.;& continue;
O&:0mpRZ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
N&0MA SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Bn"r;pqWiT }
#dLp<l) }
r $du-U }
#c0
dZ return CallNextHookEx( hHook, nCode, wParam, lParam );
hao0_9q+ }
r]{fjw(~ I@=h|GM BOOL InitHotkey()
axY-Vj {
MGO.dRy_ if(hHook!=NULL){
LC/w".oq? nHookCount++;
3_atv'I return TRUE;
."Yub];H }
fJCh else
L-d8bA hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
0;)6ZU if(hHook!=NULL)
7[-jr;v nHookCount++;
0<L@f=i return (hHook!=NULL);
Siw9_c }
tji,by#E/% BOOL UnInit()
cLlfncI {
W4CI=94 if(nHookCount>1){
(nrrzOax nHookCount--;
{K'SOhH4? return TRUE;
kXC.rgal }
'w%N(N tq BOOL unhooked = UnhookWindowsHookEx(hHook);
!9"R4~4 if(unhooked==TRUE){
q
rbF@{ nHookCount=0;
g]xZ^M+ hHook=NULL;
t%z7#}9$ }
ud:?~?j&w return unhooked;
1TQ$(bI }
tL+8nTL [Pp#l* BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
=zA=D.D2 {
H>XbqIkL@ BOOL bAdded=FALSE;
QBsDO].J< for(int index=0;index<MAX_KEY;index++){
Xs?7Whc6 if(hCallWnd[index]==0){
f9- |!]s hCallWnd[index]=hWnd;
>KY\Bx HotKey[index]=cKey;
xN"KSQpu HotKeyMask[index]=cMask;
<vt^=QA' bAdded=TRUE;
0K3FH&.% KeyCount++;
3}:pD]`h break;
J#V`W&\,6 }
K[sM)_I }
T%a]3 return bAdded;
c0G/irK }
jZ
D\u% iKabo,~ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
bOz\-=au {
,O~2
R BOOL bRemoved=FALSE;
,IJ Nuu\ for(int index=0;index<MAX_KEY;index++){
j[U0,] if(hCallWnd[index]==hWnd){
^LU[{HZV if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
@$+[IiP hCallWnd[index]=NULL;
1M;)$m: HotKey[index]=0;
:s'%IGy>: HotKeyMask[index]=0;
O[L8(+Sn bRemoved=TRUE;
;5|EpoM KeyCount--;
78QFaN$ break;
=-VV` }
$GO'L2oLwn }
fBLd5 }
PRz oLzr return bRemoved;
GC\/B0! }
kN$70N7I; QNJG}Upl void VerifyWindow()
?@#}%<yEq {
UUU^YT \ for(int i=0;i<MAX_KEY;i++){
.4Ny4CMHZ if(hCallWnd
!=NULL){ |fI%L9
if(!IsWindow(hCallWnd)){ wwAT@=X*}
hCallWnd=NULL; .E}});l
HotKey=0; }1W$9\%
HotKeyMask=0; rka:.#!
KeyCount--; K`X2N
} 2>!ykUw^O
} kxmS
} sR9F:
} ~JNuy"8
F:@Ixk?E
BOOL CHookApp::InitInstance() VxFy[rP
{ P8VU&b\
AFX_MANAGE_STATE(AfxGetStaticModuleState()); xK r,XZu
hins=AfxGetInstanceHandle(); c'B"Onu@m*
InitHotkey(); (
7?%Hg
return CWinApp::InitInstance();
flB,_
} _Nn!SE
u
.2sB6}
int CHookApp::ExitInstance() u7=[~l&L
{ 0c5_L6_z
VerifyWindow(); H+;wnI>@
UnInit(); *02( J
return CWinApp::ExitInstance(); cMl%)j-
} 1pb;A;F,A
}SV3PdE
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file Y2X1!Em>B
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) QB[s8"S
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ QC4T=E]`j
#if _MSC_VER > 1000 Z ~(XyaN
#pragma once ~qS/90,
#endif // _MSC_VER > 1000 c Vn+~m_%
[!&k?.*;<
class CCaptureDlg : public CDialog pNlisS
{ >y9o&D