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:
;{&4jcV*
pFiE2V_aS 一、实现方法
g`C"t3~%S =B'Yx 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:
"}%j' $sb@*K}:4 #pragma data_seg("shareddata")
H8B.c%_|U HHOOK hHook =NULL; //钩子句柄
p[%~d$JUq UINT nHookCount =0; //挂接的程序数目
dD'KP4Io@ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
n ~ &ssFC static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
wv\"(e7( static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
qK@,O\ static int KeyCount =0;
y?3u6q++ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
`('Up? #pragma data_seg()
Au/'|%2#( \>EUa}%xn 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。
nehk8+eV_ 2$b1q!g< DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
vO"E4s J|o<;9dg1 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
KyDd( 'i cKey,UCHAR cMask)
q3-cWfU {
}TuMMO4+ BOOL bAdded=FALSE;
1rue+GL for(int index=0;index<MAX_KEY;index++){
CN-4FI)1D9 if(hCallWnd[index]==0){
;Z;` BGZJ hCallWnd[index]=hWnd;
Eg&Q,dH[ HotKey[index]=cKey;
4\ )WMP HotKeyMask[index]=cMask;
MIZ!+[At bAdded=TRUE;
iWUxB28 KeyCount++;
e$Y7V break;
RLLL=?W@ }
tpeMq- }
{- MhhRa5 return bAdded;
@Xh8kvc81 }
,O^kZ}b //删除热键
-)bu& BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
(5y*Btd= {
;F71f#iY BOOL bRemoved=FALSE;
9WQ'"wyAQ for(int index=0;index<MAX_KEY;index++){
~j!|(a7 if(hCallWnd[index]==hWnd){
6 W$m,3Dg if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
c^&:':Z%' hCallWnd[index]=NULL;
{S%;By&[ HotKey[index]=0;
KM^}d$x}s HotKeyMask[index]=0;
X.q#ZpK bRemoved=TRUE;
j
*N^.2 KeyCount--;
kZ:~m1dd break;
KO}TCa }
-W})<{End }
#a8i($k{e }
1OqVNp%K return bRemoved;
f_hG2Sk }
$m+Pl[s *_Pkb.3R jlUT9Zp DLL中的钩子函数如下:
s <$*A;t qe0ZM-C_ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
'=(yh{W {
)D]LPCd[ BOOL bProcessed=FALSE;
T0\[":
A if(HC_ACTION==nCode)
Z yz)`>cB {
iq8Hq)I] if((lParam&0xc0000000)==0xc0000000){// 有键松开
*s2 C+@ef switch(wParam)
1'k,P;s {
=)Goip case VK_MENU:
ZQ_~
L!ot MaskBits&=~ALTBIT;
dGR #l) break;
IY(;:#l case VK_CONTROL:
SQuW`EHBgs MaskBits&=~CTRLBIT;
IUh)g1u41O break;
n.P $E case VK_SHIFT:
Ye>+ MaskBits&=~SHIFTBIT;
)$2h:dw_ break;
g%4=T~ default: //judge the key and send message
lgHzI( break;
.
vea[ }
-#AO4xpI for(int index=0;index<MAX_KEY;index++){
3[m~6Ys if(hCallWnd[index]==NULL)
Mt121Q&" continue;
oT}Sh4Wt. if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
cavzXz {
4&`d$K SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
{?IUf~< bProcessed=TRUE;
bGB5]%v, }
uv7tbI"r }
W}\<}dK }
]k.YG!$ else if((lParam&0xc000ffff)==1){ //有键按下
p!K]c D switch(wParam)
g8Zf(" {
N$8"X-na ? case VK_MENU:
.Na'yS `J MaskBits|=ALTBIT;
7bkh")^ break;
Lez]{%+.`[ case VK_CONTROL:
\3j4=K'nE MaskBits|=CTRLBIT;
93Qx+oK] break;
ob(~4H- case VK_SHIFT:
U }}E
E~W MaskBits|=SHIFTBIT;
NX<Q}3cC break;
n(Ry~Xu_ default: //judge the key and send message
[>kzQYT[ break;
Yb>A?@S }
bLz('mUY for(int index=0;index<MAX_KEY;index++){
v,c:cKj if(hCallWnd[index]==NULL)
DEKO]i continue;
t~]tw if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
3W?H^1t {
>vQKCc|93 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
lMXLd91 bProcessed=TRUE;
QPsvc6ds }
k=5v
J72U }
t$U eks }
l`AA<Rj*O- if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
Be0v&Q_NK for(int index=0;index<MAX_KEY;index++){
|DoD.?v if(hCallWnd[index]==NULL)
,#80`&\% continue;
_,|N`BBqd if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
a[V4EX1E SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
i}ti //lParam的意义可看MSDN中WM_KEYDOWN部分
s#)tiCSVW }
6C*4' P9> }
ot,e?lF }
Jb`yK@x return CallNextHookEx( hHook, nCode, wParam, lParam );
k.#[h@Pm }
#K[6Ai=We} VK$s+" 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:
n0'"/zyc 0]t7(P"F6 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
dIvvJk8 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
3=kw{r[2lM vtf`+q 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:
WLN;LT zB)wYKwZ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
(
ESmP {
\EeK<)4: if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
mF]8 {
~C ;gEE- //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
EcmyY,w SaveBmp();
1cPjgBxv# return FALSE;
qu0dWgK }
q8fnUK?i …… //其它处理及默认处理
j2,w1f}T }
NpxND0 ~-2q3U Py -D,kL 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。
JAcNjzL e!O:z 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。
n%:&N ;"DI)hdz 二、编程步骤
&<S]=\ "Bbd[ZI8 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";
{}v<2bS }VXZM7@u 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
/7XVr"R u1i
?L' 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_n~1? }h`ddo 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;
bjGQ04da 1
gx(L*y, 5、 添加代码,编译运行程序。
I r;Z+}4>Y 7W\aX*] 三、程序代码
m^ [VM&% S?LUSb ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
e.pq6D5 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
i?pC[Ao-_ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
!3Me
6&$O #if _MSC_VER > 1000
)1S"D~j- #pragma once
d7Devs
k #endif // _MSC_VER > 1000
=OF]xpI'&a #ifndef __AFXWIN_H__
0w
]
pDj #error include 'stdafx.h' before including this file for PCH
D<XRu4^; #endif
SI@Yct]<g #include "resource.h" // main symbols
9q
f=P3 class CHookApp : public CWinApp
9Kd:7@U {
s~MCt|a public:
qz/d6-0" CHookApp();
K
yFR;.F- // Overrides
joJ:*oL // ClassWizard generated virtual function overrides
"?TKz:9r //{{AFX_VIRTUAL(CHookApp)
Wc-8j2M public:
XP!7@: virtual BOOL InitInstance();
Pi:=0,"XOp virtual int ExitInstance();
`tZ`a //}}AFX_VIRTUAL
nvnJVkL9s //{{AFX_MSG(CHookApp)
/A~+32B // NOTE - the ClassWizard will add and remove member functions here.
LS4|$X4H`! // DO NOT EDIT what you see in these blocks of generated code !
_q dLA //}}AFX_MSG
2
VGGSLr DECLARE_MESSAGE_MAP()
%G>V .d };
8Nz Xe 7 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
U/I+A|S[ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
y153ax BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
qJrMr4:F BOOL InitHotkey();
G@;I^_gN BOOL UnInit();
PFnq:G^L #endif
qQ "O;_ AilfeHG //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
$*i"rlJC #include "stdafx.h"
_ 0Ced&i #include "hook.h"
bB|P`lL #include <windowsx.h>
"sU ~| #ifdef _DEBUG
[O"8Tzr #define new DEBUG_NEW
`OmYz{*r #undef THIS_FILE
L=WB'*N static char THIS_FILE[] = __FILE__;
0al8%z9e@ #endif
GcYT<pwN6 #define MAX_KEY 100
:Y ;\1J<b1 #define CTRLBIT 0x04
LQrm/)4bF5 #define ALTBIT 0x02
Ghpk0ia%d #define SHIFTBIT 0x01
eEG]JH #pragma data_seg("shareddata")
gELb(Y\ak HHOOK hHook =NULL;
<"XDIvpc%L UINT nHookCount =0;
F"M$ "rC] static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
2r|!:^'?W static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
S0<m><|kl static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
>ey-j\_v static int KeyCount =0;
!,3U_! static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
^ M4-O~ #pragma data_seg()
K'zG[[P HINSTANCE hins;
{l -V void VerifyWindow();
v
lsS BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
8^Ov.$rP //{{AFX_MSG_MAP(CHookApp)
!p~K;p, // NOTE - the ClassWizard will add and remove mapping macros here.
L7lRh=D // DO NOT EDIT what you see in these blocks of generated code!
E[RLBO[*n //}}AFX_MSG_MAP
T>;Kq;(9 END_MESSAGE_MAP()
.wfN.Z Z*rA~`@K6 CHookApp::CHookApp()
Ut
xe {
K2GcU_*t // TODO: add construction code here,
^BFD -p // Place all significant initialization in InitInstance
0fTEb%z8 }
!bi}9w 9k@`{+wmZ CHookApp theApp;
X519}
l3 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
cOr@dUSL {
SAEV " BOOL bProcessed=FALSE;
32sb$|eQq if(HC_ACTION==nCode)
KVrK:W--p {
mTW@E#)n if((lParam&0xc0000000)==0xc0000000){// Key up
`1[GY){?) switch(wParam)
bu2'JIDR {
t[ZumQ@HC case VK_MENU:
f1RfNiW. MaskBits&=~ALTBIT;
!B3lsXLSY break;
hoQ?8}r: case VK_CONTROL:
#`0iN+qh MaskBits&=~CTRLBIT;
7o4 vf~ break;
rGe^$!QB case VK_SHIFT:
F^]?'`7md MaskBits&=~SHIFTBIT;
cs%NsnZ break;
'0xJp|[xVP default: //judge the key and send message
(Q$]X5L break;
}bs2Rxkh }
KrFV4J[ for(int index=0;index<MAX_KEY;index++){
A<&:-Zz if(hCallWnd[index]==NULL)
D?w-uR%Y continue;
drQioH- if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
d[9NNm*htC {
,A>i)brc SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
/e5Fx bProcessed=TRUE;
X; gN[ }
a'v%bL;H~ }
[i '\d} }
DvuL1MeKo else if((lParam&0xc000ffff)==1){ //Key down
zq5_&AeW switch(wParam)
)^&)f!f {
LQMVC^G case VK_MENU:
%-4e8d74/ MaskBits|=ALTBIT;
sKX%<n$ break;
S"=oU}'| case VK_CONTROL:
"iof -b=ys MaskBits|=CTRLBIT;
8bX\^&N break;
\?} {wh8 case VK_SHIFT:
&\C{,:[ MaskBits|=SHIFTBIT;
rr[9sk`^H break;
rwxJR@Ttn default: //judge the key and send message
fuH Dif, break;
XKsG2>l-W }
Zv=p0xH for(int index=0;index<MAX_KEY;index++)
]'aGoR {
-BV&u( if(hCallWnd[index]==NULL)
g(:y_EpmLH continue;
B%Yb+M&K if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
a<V=C {
S)"5X)mq SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
|7zm!^t$ bProcessed=TRUE;
]sjOn?YA+ }
2="C6
7TK }
'FBvAk6 }
tE{7S/?h if(!bProcessed){
l!ye\ for(int index=0;index<MAX_KEY;index++){
aAko-,URC if(hCallWnd[index]==NULL)
!qH=l-7A continue;
MjU>qx:: if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
{kJ[) 7 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
XEZ6%Q_ }
$Mx.8FC + }
'q[V*4g }
\]J"e% return CallNextHookEx( hHook, nCode, wParam, lParam );
pAmTwe }
U
gB B`hxF(_p/ BOOL InitHotkey()
LFSOHJj {
su=.4JcK if(hHook!=NULL){
9GZF39w u nHookCount++;
d1j v>tu return TRUE;
/]xd[^ }
j.CC.[$g else
YA^9, q6u? hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
CSU> nIE0 if(hHook!=NULL)
$zCUQthL@ nHookCount++;
{uj9fE,) return (hHook!=NULL);
j)F~C8* }
%h%r6EB1F BOOL UnInit()
Ro:-u7q {
S0=BfkHi. if(nHookCount>1){
*OF7{^~& nHookCount--;
4r(rWlM return TRUE;
l}AB):<Z }
^:-%tpB#! BOOL unhooked = UnhookWindowsHookEx(hHook);
Gz *U?R-T if(unhooked==TRUE){
dm$:xE": nHookCount=0;
kd\G> hHook=NULL;
.yWdlq## }
Fr%KO)s2 return unhooked;
uR"]w7= }
+[2lS54"W4 00pHnNoxW BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
1shvHmrV {
5o~Z> BOOL bAdded=FALSE;
EoY#D'[ for(int index=0;index<MAX_KEY;index++){
w#b~R^U if(hCallWnd[index]==0){
TU. h hCallWnd[index]=hWnd;
# |UrHK; HotKey[index]=cKey;
;U`HvIch HotKeyMask[index]=cMask;
0XozYyq bAdded=TRUE;
V,M8RYOnC! KeyCount++;
_F3vC# break;
h}`<pq }
OC\C^Yh*U }
jEO; return bAdded;
\W@?revK }
sox90o 7 F37,u| BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
<I|ryPU9{X {
jA]xpf6} BOOL bRemoved=FALSE;
v5$zz w for(int index=0;index<MAX_KEY;index++){
o!H"~5Trv! if(hCallWnd[index]==hWnd){
Y2$%%@ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
5!cplx=< hCallWnd[index]=NULL;
2dI:],7 HotKey[index]=0;
L,kF] HotKeyMask[index]=0;
sU}e78m h bRemoved=TRUE;
\R#XSW, KeyCount--;
q5RLIstQ\ break;
etDB|(,z }
(8ymQ!aY }
|n&6z }
-0\$JAyrx return bRemoved;
5g&'n }
a,tP.Xsl "iydXV=Q void VerifyWindow()
vMI \$E& {
[}AcCXg`L for(int i=0;i<MAX_KEY;i++){
7PvuKAv?k if(hCallWnd
!=NULL){ [wOO)FjT
if(!IsWindow(hCallWnd)){ 54)}^ftY^
hCallWnd=NULL; g{ a0,B/j
HotKey=0; uIPR*9~6o
HotKeyMask=0; i gQyn|
KeyCount--; =Tj0dfO|"
} n_+Iw,a'm
} <St`"H
} (HJ60Hj
} Yp;x
"{:*fI;!
BOOL CHookApp::InitInstance() HU'E}8%t6
{ FJ[(dGKeE
AFX_MANAGE_STATE(AfxGetStaticModuleState()); JEd/j
zR(
hins=AfxGetInstanceHandle(); v]1rH$
InitHotkey(); 6Rt pB\hq
return CWinApp::InitInstance(); '\;tmD"N5#
} 9(I4x]`
[zfGDMG&
int CHookApp::ExitInstance() }$UFc1He\J
{ SVHtv0Nx
VerifyWindow(); &S{F"z
UnInit(); 8_LDS
return CWinApp::ExitInstance(); {p/m+m
} .KD07
I[|I\tW
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file s0h)~z
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) $200?[
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ &V;a:
#if _MSC_VER > 1000 dvf*w:5K!
#pragma once YUH/tl
#endif // _MSC_VER > 1000 -Z@p
|
jkmh6
class CCaptureDlg : public CDialog {xr]xcM'b
{ N$+"zJmw&