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:
nHbi{,3
(Q||5 一、实现方法
ejR$N!LL +-;v+{ 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
qh6b;ae\x r1IvA^X #pragma data_seg("shareddata")
@BnK C&{ HHOOK hHook =NULL; //钩子句柄
NVkYm+J# UINT nHookCount =0; //挂接的程序数目
-:d{x# static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
ec#`9w$ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
f2gh|p` static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
*>qc6d@' static int KeyCount =0;
PtUS7[] static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
Wx3DWY; #pragma data_seg()
1t/c@YUTy [-l>fP0 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。
0&NM=~ ;8vB7|54. 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:
<astIu Au P]}:E+E<.I BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
y'2w*? cKey,UCHAR cMask)
@6DKw;Q {
rC|nE=i BOOL bAdded=FALSE;
UK^w;w2F for(int index=0;index<MAX_KEY;index++){
+|S)Mm8- if(hCallWnd[index]==0){
R6 ej hCallWnd[index]=hWnd;
K%%Ow HotKey[index]=cKey;
>clVV6B HotKeyMask[index]=cMask;
+K'YVB
U} bAdded=TRUE;
.Gr"|uII KeyCount++;
M-Vz$D/aed break;
2<0".5+I }
KMb'm+ }
> (n/ return bAdded;
7?k3jDK
}
[W[awGf //删除热键
U"@p3$2QW BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
h8.(Q`tli {
gJwX BOOL bRemoved=FALSE;
f9_Pn'"I for(int index=0;index<MAX_KEY;index++){
e]!`94f if(hCallWnd[index]==hWnd){
Wn;%B].I if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
*R4=4e2#S hCallWnd[index]=NULL;
/;q3Q# HotKey[index]=0;
m#Z9wf] F HotKeyMask[index]=0;
$@{d\@U bRemoved=TRUE;
=Ldf#8J KeyCount--;
WQw11uMt@q break;
9@M;\ @&g }
vqUYr }
I`@>v%0 }
2"
v{ return bRemoved;
qa:muW }
NV}fcZ g
p|G q t]3:vp5N] DLL中的钩子函数如下:
!L|VmLqa /NPx9cLW^ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
bS|h~B]rd {
vsA/iH. BOOL bProcessed=FALSE;
)cOBP}j+ if(HC_ACTION==nCode)
4rCw#mVtB {
n]l3
)u if((lParam&0xc0000000)==0xc0000000){// 有键松开
E7SmiD@) switch(wParam)
c2gZ<[~ {
KxJDAP case VK_MENU:
b\NY!)B MaskBits&=~ALTBIT;
n%vmo
f break;
{Aj=Rj@ case VK_CONTROL:
&u2m6 r>W MaskBits&=~CTRLBIT;
]REF1<)4z break;
u8x#XESR7 case VK_SHIFT:
@Ko}Td&E( MaskBits&=~SHIFTBIT;
aNICSxDN break;
lH,/N4r*& default: //judge the key and send message
\<}e?Yx% break;
j->5%y }
*L<<S=g$2 for(int index=0;index<MAX_KEY;index++){
Q`=d5Uvw if(hCallWnd[index]==NULL)
6%c]{eTd9 continue;
K9RRY,JB if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
3P'Wk|j {
L1SZutWD? SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
d(D|rf,av bProcessed=TRUE;
JAmpU^(C }
(x[z=_I%` }
0}>p)k3&A }
;
jJ%< else if((lParam&0xc000ffff)==1){ //有键按下
{|q(4(f"Iu switch(wParam)
*@ S+J$ {
6I5LZ^/ G9 case VK_MENU:
0bQ"s*K MaskBits|=ALTBIT;
$C{-gx+: break;
Q,o"[ &Gp case VK_CONTROL:
7x$VH5jie# MaskBits|=CTRLBIT;
ukee.:{ break;
)c0 Dofhg case VK_SHIFT:
R{Me~L? MaskBits|=SHIFTBIT;
FCt %of# break;
u>03l(X6f default: //judge the key and send message
Pfg.'Bl break;
l4E0/F }
s";9G^: for(int index=0;index<MAX_KEY;index++){
0{47TX*YX if(hCallWnd[index]==NULL)
]n4G]ybK% continue;
[jKhC<t} if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
j@jUuYuDgl {
Fau24-g SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
@aWd0e] bProcessed=TRUE;
8SO(pw9 }
" ,45p@ }
vSJ#
}& }
;c# jO:A5 if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
`+T"^{
Z for(int index=0;index<MAX_KEY;index++){
IKeO&]k if(hCallWnd[index]==NULL)
AUm5$;o,/ continue;
y?xFF9W@H if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Zx%6pZ(. SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
ALp|fZ\vp //lParam的意义可看MSDN中WM_KEYDOWN部分
)#025>$z }
SGLU7*sfd }
,D{D
QJ(B }
-j}zr yG- return CallNextHookEx( hHook, nCode, wParam, lParam );
z7O$o/E-* }
s>e)\9c -pm%F8{T] 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:
>+ku:<Hw%. G@6F<L~$1 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
{} Zqaf BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
;v%f + n4Q ^ 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:
yH',vC. 03dmHg.E!E LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
&^K,"a{ {
_h P7hhR if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
7^]KQ2fF
8 {
nW_cjYS% //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
\2y[Hy? SaveBmp();
LVBE+{P\5? return FALSE;
T5+9# }
bG!/%,s …… //其它处理及默认处理
:Mnl 1;oh }
7SJtW`~ 3|1v)E Qis/'9a 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。
[|APMMYK1 \) g?mj^ 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。
cFloaCz A0gRX] 二、编程步骤
)s>R~7 ECvTmU'= 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";
u:%Ln_S ' )KuLVE}S 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
`:YCOF g3vR\?c` 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;
G Y+li{ {1J4Q[N9m 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;
h=MEQ-3jg -~`)V`@ 5、 添加代码,编译运行程序。
=]W[{@P f2Z(hYH~ 三、程序代码
+;N;r/d_i ?4YLt|sn ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
D Ax1 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
|sPUb;&~ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
Yp;?Zq9 #if _MSC_VER > 1000
iO{LsG*5Z #pragma once
. MH;u3U #endif // _MSC_VER > 1000
kuW^_BROJ #ifndef __AFXWIN_H__
$'93:9tg #error include 'stdafx.h' before including this file for PCH
V5bB$tL}3 #endif
T3h 1eU #include "resource.h" // main symbols
*w[0uQL5Z class CHookApp : public CWinApp
`clp#l.ii {
M. fA5rJ^ public:
"{M?,jP# CHookApp();
$9?<mP2-* // Overrides
hf< [$B // ClassWizard generated virtual function overrides
@5*$yi 'Cp //{{AFX_VIRTUAL(CHookApp)
@k||gQqIB public:
-s9()K(vZG virtual BOOL InitInstance();
Nd%j0lj virtual int ExitInstance();
j},3@TFh //}}AFX_VIRTUAL
9
f=~E8P //{{AFX_MSG(CHookApp)
ygYy [IZ // NOTE - the ClassWizard will add and remove member functions here.
J)P7QTC // DO NOT EDIT what you see in these blocks of generated code !
X
v$"B-j //}}AFX_MSG
cng166}1A DECLARE_MESSAGE_MAP()
80 ckh };
OzAxnd\.N LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
5N:IH@ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
$Ahe Vps@@ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
"43F.!P BOOL InitHotkey();
N%!{n7`N: BOOL UnInit();
w
L4P-4' #endif
>IJX=24Rc _~O*V& //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
c[a^fu! #include "stdafx.h"
c]R27r E #include "hook.h"
N}KL' #include <windowsx.h>
t_jnp $1m #ifdef _DEBUG
8QQh1q2 #define new DEBUG_NEW
nt$q< 57 #undef THIS_FILE
!uqp?L^; static char THIS_FILE[] = __FILE__;
5+a5pC #endif
>Xw0i\G #define MAX_KEY 100
=TJ9Gr/R&: #define CTRLBIT 0x04
hr3<vWAD #define ALTBIT 0x02
puox^ #define SHIFTBIT 0x01
2&XNT-Qm #pragma data_seg("shareddata")
Tb}op XYK HHOOK hHook =NULL;
*1,4#8tB UINT nHookCount =0;
IO<Ds#( static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
Ix+eP|8F static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
PP8627uP static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
%F13*hOu static int KeyCount =0;
<"{VVyK static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
}mpFo2 #pragma data_seg()
BRXDE7vw HINSTANCE hins;
)
(0=w4 void VerifyWindow();
DqHJ *x4 BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
pKaU
[1x?% //{{AFX_MSG_MAP(CHookApp)
USZBk0$ // NOTE - the ClassWizard will add and remove mapping macros here.
r*9*xZ>8u // DO NOT EDIT what you see in these blocks of generated code!
2=uwGIF //}}AFX_MSG_MAP
0G`@^` END_MESSAGE_MAP()
63/a 0Yn
@W-0ybv CHookApp::CHookApp()
C%H?vrR {
yX/{eX5dr // TODO: add construction code here,
$N\k*= // Place all significant initialization in InitInstance
8&yI1XM| }
lN*beOj B_
bZa CHookApp theApp;
wU|jw( LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
ic}mru {
L}rYh`bUP[ BOOL bProcessed=FALSE;
0X5b32 if(HC_ACTION==nCode)
K
#}t\ {
6B+?X5-6DH if((lParam&0xc0000000)==0xc0000000){// Key up
D~ n-;T switch(wParam)
d .%2QkL {
Yz#E0aTTA case VK_MENU:
_ Y7Um MaskBits&=~ALTBIT;
`R!Q(rePx break;
g{CU1c)B case VK_CONTROL:
k/1S7X[ MaskBits&=~CTRLBIT;
wV-9T*QrM break;
<!F".9c@A case VK_SHIFT:
#n]K$k> MaskBits&=~SHIFTBIT;
oxL)Jx\c9A break;
[}yPy))A default: //judge the key and send message
j8c5_& break;
}{)Rnb@
> }
6q^\pJY%&7 for(int index=0;index<MAX_KEY;index++){
hbEqb{#}@ if(hCallWnd[index]==NULL)
#4<=Ira5 continue;
g'cVsO)S if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
aW9\h_$ {
xjD."q SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
X8):R- J bProcessed=TRUE;
kPoz&e_@ }
9sI&d }
*7b?.{ }
Vh>|F}%E else if((lParam&0xc000ffff)==1){ //Key down
u U%Z%O switch(wParam)
LW k/h1 {
W8F@nY case VK_MENU:
sR/y| MaskBits|=ALTBIT;
'x5p ?m break;
*W;;L_V" case VK_CONTROL:
sf/m@425 MaskBits|=CTRLBIT;
TbLU[(m-n break;
q3C case VK_SHIFT:
4U~'Oa@p MaskBits|=SHIFTBIT;
m_.9PZ break;
L/In~'*- default: //judge the key and send message
W]XM<# ^^ break;
0!oqP1 }
T}/|nOu
5 for(int index=0;index<MAX_KEY;index++)
suE8"v!sk {
wY ??#pS if(hCallWnd[index]==NULL)
uQ|LkL%<^ continue;
LH.Gf if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
m#[9F']Z` {
#+i:s92], SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
B):ZX# bProcessed=TRUE;
LcB+L]( }
-xbs'[ }
cQ'x]u_ }
mE_% if(!bProcessed){
4>OS2b`.; for(int index=0;index<MAX_KEY;index++){
/:ZwGyT; if(hCallWnd[index]==NULL)
(:F]@vT continue;
&xA>(|a\&- if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
:aBm,q9i:} SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
]_|'N7J }
EIfqRRTA }
y4l-o }
H4sW%nZ0 return CallNextHookEx( hHook, nCode, wParam, lParam );
m(o`; }
;u[:J #!E`%'
s] BOOL InitHotkey()
nCQ".G {
E0/>E if(hHook!=NULL){
#-PMREgO nHookCount++;
|?ZU8I^vW return TRUE;
mln4Vl(l2M }
WrcmC$ff else
#d*0
)w hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
RyU8{-q if(hHook!=NULL)
5*+DN
U@ nHookCount++;
q*5L", return (hHook!=NULL);
7VG*Wu }
LT>_Y`5> BOOL UnInit()
hW'b'x< {
v\CBw" if(nHookCount>1){
."gq[0_YS nHookCount--;
j}d):3! return TRUE;
DaJ,(DJY }
wEwRW BOOL unhooked = UnhookWindowsHookEx(hHook);
$${3I4 if(unhooked==TRUE){
8EMBqhl nHookCount=0;
cvo+{u$s hHook=NULL;
dNY'uv&Y }
Thu_`QP^ return unhooked;
U;IGV~oT }
$MGKGWx@E ,X1M!' BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
CM$&XJzva {
rk4KAX_[ BOOL bAdded=FALSE;
;Z`a[\i': for(int index=0;index<MAX_KEY;index++){
:3XvHL0rx if(hCallWnd[index]==0){
_'17C/ hCallWnd[index]=hWnd;
lZ)6d-vK HotKey[index]=cKey;
xf/K+ HotKeyMask[index]=cMask;
.AOc$Nt bAdded=TRUE;
mtkZF{3Jx KeyCount++;
ms;zC/ break;
]kx<aQ^ }
']fyD3N }
S.Kcb=;"L return bAdded;
j,;f#+O`g }
J%|; )/JVp> BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
8t=O=l\ {
maHz3: BOOL bRemoved=FALSE;
wr:W}Z@pL for(int index=0;index<MAX_KEY;index++){
H ?9Bo! if(hCallWnd[index]==hWnd){
("ix!\1K@ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
38m9t' hCallWnd[index]=NULL;
W1<*9O HotKey[index]=0;
^|6#Vx HotKeyMask[index]=0;
YpXd5;' bRemoved=TRUE;
`GBJa k KeyCount--;
AzF*4x break;
& wtE"w }
!vRN'/(Vyu }
|f$ws R`& }
f*rub. y return bRemoved;
DJ7ak>"R
}
jtpHDS d}fd^x/ void VerifyWindow()
Sz<:WY/(x {
Gey-8 for(int i=0;i<MAX_KEY;i++){
_<jU! R if(hCallWnd
!=NULL){ V"(5U(v{~
if(!IsWindow(hCallWnd)){ ,r~^<m
hCallWnd=NULL; l3u+fE,;_
HotKey=0; 1 oKY7i$
HotKeyMask=0; #o[n.
KeyCount--; .sQV0jF {
} r}e(MT:R'
} 'YGP42#
} K3h];F!^
} {+cx} `
U';)]vB$
BOOL CHookApp::InitInstance() [tSv{
{ PPrvVGP
AFX_MANAGE_STATE(AfxGetStaticModuleState()); ewN|">WXQ
hins=AfxGetInstanceHandle(); 3I)oqS@q'
InitHotkey(); I4w``""c
return CWinApp::InitInstance(); %%n&z6w