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:
OW@"j;6
3`
atw*t1)g 一、实现方法
jeJspch+# qk>SM|{ 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:
yeBfzKI{b PgHmOs #pragma data_seg("shareddata")
d$xvM HHOOK hHook =NULL; //钩子句柄
_wX(OB UINT nHookCount =0; //挂接的程序数目
{d]B+' static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
2J%L%6z8~ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
~4O3~Y_+GN static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
I+S fZ:q^ static int KeyCount =0;
MPn/"Fij$ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
-B!
a
O65^ #pragma data_seg()
`T{CB) ?9 AK%&Kq&PaY 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。
cLvnLaA} lj:.}+]r 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:
w=: c7Y+ cIC/3g}] BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
{'B(S/Z7 cKey,UCHAR cMask)
5e1oxSU {
Gpcordt/ BOOL bAdded=FALSE;
'.8eLN for(int index=0;index<MAX_KEY;index++){
1?3+> if(hCallWnd[index]==0){
(w\|yPBB hCallWnd[index]=hWnd;
13)6p|6x HotKey[index]=cKey;
q?)5yukeF HotKeyMask[index]=cMask;
TU6YS< bAdded=TRUE;
aY;34SF KeyCount++;
j9GKz1 break;
e'c3.sQ|? }
7y42)X }
o?~27 return bAdded;
8 nqF i }
qJO6m-
//删除热键
%e)vl[:} BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Y,EF'Ot {
+JY8"a97> BOOL bRemoved=FALSE;
JUXBMYFus for(int index=0;index<MAX_KEY;index++){
!0|&f>y if(hCallWnd[index]==hWnd){
L<XX?I\p if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
#7]>ozKm hCallWnd[index]=NULL;
r'_#rl HotKey[index]=0;
u$aN~6HG HotKeyMask[index]=0;
bY*_6SPK4 bRemoved=TRUE;
$}5M`p\&C KeyCount--;
Z=;=9<vA break;
e%4vvPp }
lw?C:-m }
%[ *+ }
(~! @Uz5 return bRemoved;
*CAz_s< }
.y_ ~mr&d )"|wWu nD>X?yz2 DLL中的钩子函数如下:
:_2:Fh.}3~ oL }d=x/ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
HU|qeSyel {
ZtP/|P5@ BOOL bProcessed=FALSE;
odJE~\\hw if(HC_ACTION==nCode)
H!,V7R {
RdL5VAD if((lParam&0xc0000000)==0xc0000000){// 有键松开
!vc5NKv#n switch(wParam)
~k?t {
;05lwP*r] case VK_MENU:
g2*}XS3 MaskBits&=~ALTBIT;
$P#+Y,r~\ break;
s|Vs#o.P) case VK_CONTROL:
.i*ja* MaskBits&=~CTRLBIT;
Z=%u:K}[ break;
'%:E4oI case VK_SHIFT:
1rU\ !GfR MaskBits&=~SHIFTBIT;
f,LeJTX= break;
AXi4{Q, default: //judge the key and send message
i.[k"( break;
m7XN6zX }
%u<r_^w5 for(int index=0;index<MAX_KEY;index++){
jGJf[:M&Pm if(hCallWnd[index]==NULL)
'd;aAG continue;
)cZ KB0*+ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
W?.xtQEv {
jv1p'qs4 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
K@!hrye bProcessed=TRUE;
)=aqj@v }
B>z^W+Unyn }
C:bA:O }
<S;YNHLC else if((lParam&0xc000ffff)==1){ //有键按下
XRyeEwA;pp switch(wParam)
d4Y[}Fcp+ {
2)n%rvCQ case VK_MENU:
Gz8JOl MaskBits|=ALTBIT;
LUz`P6 break;
y^kC2DS case VK_CONTROL:
a{%EHL,F MaskBits|=CTRLBIT;
U~c9PqjZ break;
R iV]SgV9 case VK_SHIFT:
_+}hId MaskBits|=SHIFTBIT;
YhAO break;
rEU1
VvE default: //judge the key and send message
!}1l8Y break;
y] Cx[ }
=FFs8&PKys for(int index=0;index<MAX_KEY;index++){
o$*DFvk if(hCallWnd[index]==NULL)
CPP9=CoR37 continue;
9+5F(pd( if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
c]z^(:_> {
Ml+f3#HP SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
8-b~p bProcessed=TRUE;
=U:]x'g( }
CaoQPb* }
&;GoCU Le }
]Rp<64I o if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
v{\~>1J{ for(int index=0;index<MAX_KEY;index++){
|Z Cv>8?n if(hCallWnd[index]==NULL)
P5"B7>L: continue;
"e29j'u!* if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
OU mZ| SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Tilr%D(Q //lParam的意义可看MSDN中WM_KEYDOWN部分
i@<w"yNd_ }
Q-U,1b }
gKIN* Od }
~IQjQz? return CallNextHookEx( hHook, nCode, wParam, lParam );
k<"N^+GSz }
=aehhs> Rob:W| 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:
aIWpgUd` (ijO|%? BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
MUN:}S BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
bs?4|#[K *S Z]xrs 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:
C{ Z*5) )*o) iN 7l LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
W`n_m&Y\ {
.=c@ps if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
^4saB+qm {
ZQ[s: //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
xrJ0 SaveBmp();
Ac[;S!R return FALSE;
x_H"<-By }
[Kbna>` …… //其它处理及默认处理
;{n*F=%uC }
G0ENk|wbbj 0XL[4[LdA \nQEvcH 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。
i{J[;rV9 >>=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。
.3
^*_ q#Ik3 5 二、编程步骤
Yc(lY
N QkO4Td< 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";
#P1;*m YeF'r.Y 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
|C t Q <R#:K7>O 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;
w Kz*)C $5>x)jr:w+ 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
,z0E2 +6Vu]96=KC 5、 添加代码,编译运行程序。
81wmKqDEs eA/}$.R 三、程序代码
a6op -ktYS(8& ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
WxF@'kdn*, #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
e}L(tXZ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
;[Hrpl
S #if _MSC_VER > 1000
R"PO@v #pragma once
P~"""3de4 #endif // _MSC_VER > 1000
xtp55"g #ifndef __AFXWIN_H__
KV'-^\ #error include 'stdafx.h' before including this file for PCH
6r,zOs-I] #endif
q.lh #include "resource.h" // main symbols
m$q* class CHookApp : public CWinApp
u #7AB>wi{ {
/B public:
jbTyM"Y CHookApp();
j !`2Z@ // Overrides
]g9n#$|. // ClassWizard generated virtual function overrides
=iPQ\_ON@ //{{AFX_VIRTUAL(CHookApp)
' }NH$ KA public:
#Cz:l|\ i virtual BOOL InitInstance();
VH.}}RS% virtual int ExitInstance();
0'*'%Iga //}}AFX_VIRTUAL
Cd7d-'EQn //{{AFX_MSG(CHookApp)
<NM Os"NB // NOTE - the ClassWizard will add and remove member functions here.
UgLJV2M6 // DO NOT EDIT what you see in these blocks of generated code !
mHC36ba //}}AFX_MSG
_Hq)mF DECLARE_MESSAGE_MAP()
gr$H?|n l };
RjX#pb LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
H*>5ne=x BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
. J*2J(T, BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
N" oJ3-~ BOOL InitHotkey();
%] 7.E BOOL UnInit();
ymyk.#Z<% #endif
!^A t{[U 2O9OEZdKB //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
,1e@Y~eZ #include "stdafx.h"
>(a/K2$*1 #include "hook.h"
HLM"dmI #include <windowsx.h>
= G3A} #ifdef _DEBUG
\[x4 #define new DEBUG_NEW
9L9mi<, #undef THIS_FILE
3Kum static char THIS_FILE[] = __FILE__;
90)rOD1B #endif
$d7{ q3K&1 #define MAX_KEY 100
YyR~pT#ffT #define CTRLBIT 0x04
HnfTj 5J@ #define ALTBIT 0x02
+UP?M4g #define SHIFTBIT 0x01
n
6|\ #pragma data_seg("shareddata")
R2[!h1nZ HHOOK hHook =NULL;
Rd*/J~TK UINT nHookCount =0;
3836Di:{ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
Cqk6I gw static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
LIHf]+ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
%5H>tG`] static int KeyCount =0;
L"!BN/i_ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
Q /\Hc #pragma data_seg()
K?+Rq HINSTANCE hins;
_qqJ>E<0 void VerifyWindow();
\7,'o] >M- BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
v|mZcAz //{{AFX_MSG_MAP(CHookApp)
6e;.}i // NOTE - the ClassWizard will add and remove mapping macros here.
\<A@Nf" // DO NOT EDIT what you see in these blocks of generated code!
|4a#O8d //}}AFX_MSG_MAP
zHCz[jlrMq END_MESSAGE_MAP()
U=bZy,FT$ I^6zUVH CHookApp::CHookApp()
Djf,#&j!3 {
wA}+E)x/C // TODO: add construction code here,
ffYiu4$m // Place all significant initialization in InitInstance
th*E"@ }
JEes'H}Y z '%Vy CHookApp theApp;
];go?.*C LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
XX(;,[(_ {
?wx|n_3<: BOOL bProcessed=FALSE;
1cdM^k if(HC_ACTION==nCode)
C,D~2G {
etH%E aF[ if((lParam&0xc0000000)==0xc0000000){// Key up
dGzZ_Vf switch(wParam)
*l^%7Wrk {
4<&`\<jZ case VK_MENU:
qcfLA~y MaskBits&=~ALTBIT;
3J}bI{3 break;
up7]Yy;o= case VK_CONTROL:
jM3{A;U2 MaskBits&=~CTRLBIT;
<&rvv4*H break;
YvK8;<k@-? case VK_SHIFT:
RtR]9^:~ MaskBits&=~SHIFTBIT;
)y:~T\g break;
VscEdtkd default: //judge the key and send message
fW4N+2 break;
f z8eL:i: }
[?hc.COE for(int index=0;index<MAX_KEY;index++){
o3l_&?^ if(hCallWnd[index]==NULL)
Xu:Sh<:R continue;
'DQKpk' if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
(v8jVbg {
m>6,{g) SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
j{9sn,<: bProcessed=TRUE;
xAD: Z" }
nV%1/e"5 }
v7/qJ9l }
e? fFh,a else if((lParam&0xc000ffff)==1){ //Key down
~V"D|U;i + switch(wParam)
pRj1b^F5y {
D[)g-_3f6< case VK_MENU:
Dw^d!%Ala MaskBits|=ALTBIT;
*eytr#0B- break;
ALiXT8q case VK_CONTROL:
m$:o+IH/ MaskBits|=CTRLBIT;
b{t'Doe break;
Uok?FEN case VK_SHIFT:
lM5Xw MaskBits|=SHIFTBIT;
=?3D:k7z break;
Nd*zSsVlq default: //judge the key and send message
M: qeqn+ break;
,xrXby|R" }
?y7x#_Exc for(int index=0;index<MAX_KEY;index++)
`2?9eXC {
:'!,L0I|t if(hCallWnd[index]==NULL)
kQ~*iY continue;
$aX}i4F if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
BXVmt!S5F {
Sf)VQ5U!Y SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
2mbZ6'p { bProcessed=TRUE;
4*_9Gl }
`bffw:;% }
=LS?:Mhm }
40oRO0p if(!bProcessed){
-Vk+zEht for(int index=0;index<MAX_KEY;index++){
[dL4u^]{ if(hCallWnd[index]==NULL)
c?CjJ}-7 continue;
9Ay*' if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
_rK}~y=0 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
b&Qj`j4]ZM }
a="Z]JGk }
!~cTe!T }
C9U~lcIS return CallNextHookEx( hHook, nCode, wParam, lParam );
*S_eYKSl }
eqQA st#~ m#mM2Guxe BOOL InitHotkey()
!h{qO&ZH= {
`6b!W0$
- if(hHook!=NULL){
}r6SV%]: nHookCount++;
G_g~-[O return TRUE;
J
A ]s }
'@9h@,tc else
GH![rK hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
b:Dr_| if(hHook!=NULL)
)W~w72j- nHookCount++;
# &o3[.)9 return (hHook!=NULL);
"*WzoRA={ }
=m=`| Bn BOOL UnInit()
!12W(4S5 {
52BlFBNV if(nHookCount>1){
2Tt@2h_L nHookCount--;
Bhl@\Kq return TRUE;
o-B9r+N }
IDb|J%e^P BOOL unhooked = UnhookWindowsHookEx(hHook);
JGp~A#H& if(unhooked==TRUE){
&+=A;Y) nHookCount=0;
_* ] ~MQ= hHook=NULL;
n3-u.Fb }
PBb@J'b return unhooked;
+s
c|PB }
J.mEOo!> &""~Pn8 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
K.n #;| {
L{;q ^ BOOL bAdded=FALSE;
7M<Ae
D% for(int index=0;index<MAX_KEY;index++){
<XX\4[wb if(hCallWnd[index]==0){
q4PRc<\^ hCallWnd[index]=hWnd;
H?8KTl=e HotKey[index]=cKey;
r>sk@[4h HotKeyMask[index]=cMask;
]QM6d(zDA bAdded=TRUE;
)Fk%,H-1 KeyCount++;
`9Zoq=/ break;
.0S.7w3dZo }
9`+c<j4/B }
UwrinkoeE return bAdded;
I|,^a|\ }
2GA6@-u\ V=BF"S;-' BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
MOY.$M,1 {
MRiQaUg2 BOOL bRemoved=FALSE;
mF[w-<:.d for(int index=0;index<MAX_KEY;index++){
ScYw3i if(hCallWnd[index]==hWnd){
f@+[-yF if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
as-
Z)h[B hCallWnd[index]=NULL;
&!vJ3: HotKey[index]=0;
kN>%y&cK HotKeyMask[index]=0;
abUvU26t bRemoved=TRUE;
)V%xbDd S KeyCount--;
C] qY break;
~T9%%W[ }
u[dR*o0' }
Ey=(B'A~ }
M2_sxibI return bRemoved;
.a1WwI
}
]d}Z2I' <ZxxlJS)6 void VerifyWindow()
k:Sxs+)?1 {
$R%xeih1fz for(int i=0;i<MAX_KEY;i++){
pHEhB9_A! if(hCallWnd
!=NULL){ YA O,
rh
if(!IsWindow(hCallWnd)){ Wo2TU!
hCallWnd=NULL; 8i=J(5=
HotKey=0; 2ixg
ix
HotKeyMask=0; }BS.OK?
KeyCount--; %*lOzC
} T~7i:<E^
} 7R[4XQ%
} PuqT&|wP l
} ehl){Dd^
-$J\BkI
BOOL CHookApp::InitInstance() #"fBF/Q
{ N%%2!Z#
AFX_MANAGE_STATE(AfxGetStaticModuleState()); RrRrB"!8nR
hins=AfxGetInstanceHandle(); N_lQz(nG/2
InitHotkey(); la>:%SD
return CWinApp::InitInstance(); ;BUJ5
} }20
Q`?
Uc%(#I]Mi
int CHookApp::ExitInstance() b26#0;i
{ fi^I1*S
VerifyWindow(); b[<