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:
`*Yw-HL
UxL*I[z5 一、实现方法
4d`YZNvZW/ qFD ZD)K 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:
3Rc*vVnI 4~,Z ' k #pragma data_seg("shareddata")
d
#1Y^3n HHOOK hHook =NULL; //钩子句柄
H"FK(N\ UINT nHookCount =0; //挂接的程序数目
*{3d+j/?/ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
lG)wa static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
QQBh)5F static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
QkBw59L7 static int KeyCount =0;
E
+_n@t" static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
<%m YsaM #pragma data_seg()
+b(};(wL zbmC?2$ 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。
5Jbwl$mZ ~ubvdQEW DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
!BsQJ_H ~Jk&!IE2 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
,B[j{sE cKey,UCHAR cMask)
tw_o?9 {
moM?aYm BOOL bAdded=FALSE;
g}s$s} for(int index=0;index<MAX_KEY;index++){
7v*gwBH if(hCallWnd[index]==0){
ZeP=}0TGjn hCallWnd[index]=hWnd;
zY*9M3(X HotKey[index]=cKey;
Qs elW] HotKeyMask[index]=cMask;
j|t=%* bAdded=TRUE;
3[ xdls KeyCount++;
ECOJ .^ break;
~Q&J\'GQH }
HU'Mi8xxy }
ob\-OMNs@ return bAdded;
K6kz{R%` }
inWLIXC,
//删除热键
,X.[37 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
z:>cQUYl {
2aj1IBnz6/ BOOL bRemoved=FALSE;
8:$h&aBI for(int index=0;index<MAX_KEY;index++){
t(u2%R4<d if(hCallWnd[index]==hWnd){
=]%JTGdp( if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
vN Bg&m hCallWnd[index]=NULL;
|NuMDVd+s HotKey[index]=0;
~[HzGm% HotKeyMask[index]=0;
CRK%^3g bRemoved=TRUE;
<rBW6o7 KeyCount--;
XOvJlaY)'. break;
\rS*\g:i }
4j#y?^s }
(xHmucmwp }
J].Oxch&y return bRemoved;
n93q8U6m/U }
?{ N,&d IrMHAM5K >Uw:cq DLL中的钩子函数如下:
)0VL$A 'z ?Hv LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
x4WCAqi/2 {
z`zz8hK. BOOL bProcessed=FALSE;
geme_ if(HC_ACTION==nCode)
eFG/!b<17 {
3`bQ0-D; if((lParam&0xc0000000)==0xc0000000){// 有键松开
;P91'B~t switch(wParam)
UxGu1a {
NoiB98g case VK_MENU:
ek][^^4o MaskBits&=~ALTBIT;
.PB!1C.}@ break;
aJ'Fn case VK_CONTROL:
32wtN8kx MaskBits&=~CTRLBIT;
#AJW-+1g.= break;
=I# pXL case VK_SHIFT:
YnEyL2SuU MaskBits&=~SHIFTBIT;
'H530Y\ break;
|0n )U( default: //judge the key and send message
Gyq 6? break;
?()*"+N(ck }
W'C>Fn}lO? for(int index=0;index<MAX_KEY;index++){
7hHID>,o9% if(hCallWnd[index]==NULL)
0V:H/qu8> continue;
|'h(S| if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
L/i'6(=" {
z@,pT"rb SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
1}d
F,e bProcessed=TRUE;
Va8
}JD }
UY3)6}g6 }
ZC?~RXL( }
t<45[~[ else if((lParam&0xc000ffff)==1){ //有键按下
(Ceru o S switch(wParam)
i!a!qE.1 {
}j/\OY _& case VK_MENU:
Rw?w7?I MaskBits|=ALTBIT;
)]fsl_Yq break;
3Bl|~K;- case VK_CONTROL:
Z>g72I%X MaskBits|=CTRLBIT;
"V[j&B)P break;
w!m4>w case VK_SHIFT:
4|?(LHBD) MaskBits|=SHIFTBIT;
1aAOT6h break;
Qc7*p]E& default: //judge the key and send message
[+\He/M6 break;
2j-l<!s }
A%^?z. for(int index=0;index<MAX_KEY;index++){
ctP+ECH if(hCallWnd[index]==NULL)
n9Fq^^? continue;
evyjHc Cx if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
RN`TUCQL {
:Qa*-)rs SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
\rr"EAk] bProcessed=TRUE;
Va?]:Q }
jwI2T$ }
BZ?w}%-MO }
JN8Rh if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
aT,WXW* for(int index=0;index<MAX_KEY;index++){
2XR!2_)O5 if(hCallWnd[index]==NULL)
K*:=d}^ continue;
T\gs if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Fl)nmwOc SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
%e:+@%] //lParam的意义可看MSDN中WM_KEYDOWN部分
F@<cp ?dR }
>g$iO`2 }
1)~|{X+~ }
O C&BJNOi return CallNextHookEx( hHook, nCode, wParam, lParam );
x// uF }
f&vMv. !KI^Z1dP( 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
Fg`<uW]TFZ p*<Jg l BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
/we]i1-9 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
]y#'U 'd
N1~Pa 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
#w''WOk@ZG f>Rux1Je4 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
x_3B) &9 {
&$XTe2 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
?l~qb]._ {
:Quep-:fy< //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
#H6YI3
`G SaveBmp();
)xVf3l
pQ return FALSE;
lW"0fZ_x'E }
~C{:G;Iy0 …… //其它处理及默认处理
-3ePCAtXbe }
S:z|"u:+ >$ZhhM/} J Tv#d>ZSD 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
6?xF!VIL
L]l/w 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
iY>P7Uvvz k9eyl) 二、编程步骤
?$`kT..j,u \dQc!)&C9 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";
Yz;7g8HI 3D6&0xTq 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
B*:I-5 0:Bpvl5 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;
%<^^ Mw bGwOhd<. 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;
BvvjaC TFOx=_.%i 5、 添加代码,编译运行程序。
Wu6'm&t Lv@WI6DM
三、程序代码
UIU Pi
gd m=n79]b:N ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
;%0kzIvP #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
bj`GGxzOb #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
iuj%.}
#if _MSC_VER > 1000
]Sj;\Iz #pragma once
NU_^*@k #endif // _MSC_VER > 1000
Zb_A(mnzh #ifndef __AFXWIN_H__
2c]751 #error include 'stdafx.h' before including this file for PCH
RL&0?OT #endif
J<L\IP?% #include "resource.h" // main symbols
Y*#xo7#B class CHookApp : public CWinApp
P84YriLo {
vJs6nVbK public:
'Ev[G6vo CHookApp();
HT/!+#W. // Overrides
,8zJD&HMx // ClassWizard generated virtual function overrides
i%!<9D~n //{{AFX_VIRTUAL(CHookApp)
[PN2^ public:
6&]Z'nW0k virtual BOOL InitInstance();
Vs TgK virtual int ExitInstance();
)o:sDj`b] //}}AFX_VIRTUAL
BEax[=&W //{{AFX_MSG(CHookApp)
\s[L=^! // NOTE - the ClassWizard will add and remove member functions here.
K. B\F)K // DO NOT EDIT what you see in these blocks of generated code !
dfAw\7v/ //}}AFX_MSG
l1kHFeq DECLARE_MESSAGE_MAP()
<r <{4\%} };
p5qfv>E8) LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
&_]G0~e BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
^X6e\]yj BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
&*o4~6pQ# BOOL InitHotkey();
,FP0n BOOL UnInit();
i+5Qs-dHA #endif
6Br^Ugy :Z/\U*6~ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
'0~?zP #include "stdafx.h"
W\-`}{B_/ #include "hook.h"
2ZV; GS# #include <windowsx.h>
2!LDrvPP #ifdef _DEBUG
3{.]! #define new DEBUG_NEW
f"gYXaVF+ #undef THIS_FILE
#qk=R7"Q static char THIS_FILE[] = __FILE__;
/":/DwI' #endif
dn}EM7:Z #define MAX_KEY 100
tBkgn3w #define CTRLBIT 0x04
Q_p&~ PNy5 #define ALTBIT 0x02
iz;5: #define SHIFTBIT 0x01
/JRZ?/<1 #pragma data_seg("shareddata")
|%5pzYe HHOOK hHook =NULL;
O*/%zr UINT nHookCount =0;
S]=.p-Am static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
S0OL;[*. static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
ZD]{HxGL! static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
fJ\?+, static int KeyCount =0;
] 7[#K^ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
*.eeiSi{ #pragma data_seg()
E$z- |-{> HINSTANCE hins;
cQxUEY('+ void VerifyWindow();
TDZ==<C BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
Py#EjF12 //{{AFX_MSG_MAP(CHookApp)
#-Mr3 // NOTE - the ClassWizard will add and remove mapping macros here.
Wm" q8-<< // DO NOT EDIT what you see in these blocks of generated code!
8.jf6 //}}AFX_MSG_MAP
"6IZf>N@# END_MESSAGE_MAP()
1`|Z8Jpocj 0827z CHookApp::CHookApp()
h3.CvPYy1 {
m+8:_0x " // TODO: add construction code here,
:FU?vh$) // Place all significant initialization in InitInstance
@i> r(X }
Z3MhHvvgp{ F5+FO^3E CHookApp theApp;
M
hW9^? LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
wO.d;SK {
WJ-.?
BOOL bProcessed=FALSE;
9;I%Dv if(HC_ACTION==nCode)
Zgp9Uu}" {
a_/4 ^+ if((lParam&0xc0000000)==0xc0000000){// Key up
doTbol?+ switch(wParam)
&c"!Y)%G {
!4#qaH-Q case VK_MENU:
&/Gn!J;1 MaskBits&=~ALTBIT;
)uAY_()/ break;
DazoY&AWE case VK_CONTROL:
X0+E!~X$zM MaskBits&=~CTRLBIT;
2o9B >f&g break;
` ;mQ"lO case VK_SHIFT:
#hn MaskBits&=~SHIFTBIT;
<K&A/Ue break;
^HR8.9^[1u default: //judge the key and send message
M]k Q{( break;
xMQ>,nZ }
At[Q0'jkc for(int index=0;index<MAX_KEY;index++){
|*w)]2Bl if(hCallWnd[index]==NULL)
:zo5`[P continue;
1yz%ud-l if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
V:j^!* {
E<tR8='F SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
2 <OU)rVE4 bProcessed=TRUE;
-z.
wAp }
CV^%'HIs?+ }
Dz$w6d }
LKI\(%ba# else if((lParam&0xc000ffff)==1){ //Key down
,<K+.7,)E switch(wParam)
ZY7-. {
%E#Ubm! case VK_MENU:
*7Y#G8 s MaskBits|=ALTBIT;
"8uNa break;
p*g)-/mA case VK_CONTROL:
un!v1g9O MaskBits|=CTRLBIT;
3O4lGe#u break;
V;R gO} case VK_SHIFT:
g i/k#3_m MaskBits|=SHIFTBIT;
Iv3yDL; break;
S?`0,F default: //judge the key and send message
r)-{~JA! break;
Jb$G }
12L`Gi for(int index=0;index<MAX_KEY;index++)
qHgtd+
I {
4qE4 i:b if(hCallWnd[index]==NULL)
kmTYRl
)j continue;
i)(G0/: if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
V.$tq {
urkuG4cY SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
)lt1I\n*k bProcessed=TRUE;
Opf)TAl{ }
~a3u['B }
~vpF|4Zn5 }
*2~WP'~PQd if(!bProcessed){
mE{QT ZS for(int index=0;index<MAX_KEY;index++){
<X{w^
cT_Q if(hCallWnd[index]==NULL)
#mUQ@X@K continue;
C4PT(cezR if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
#6#n4`%ER SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
R!/JZ@au< }
4P)#\$d: }
1 Vc_jYO@ }
S9$,.aq return CallNextHookEx( hHook, nCode, wParam, lParam );
3)CIqN }
aynaV 2/t; }pw8 BOOL InitHotkey()
j>\rs|^O {
Z@x& if(hHook!=NULL){
cs\=8_5 nHookCount++;
t 3N}): return TRUE;
t@#5
G*
_Q }
(i(E~^O else
n7~3~i`D; hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
vvY?8/ if(hHook!=NULL)
5CcX'*P nHookCount++;
_hl| 3
eW5 return (hHook!=NULL);
r90tXx }
`EMGrw_ BOOL UnInit()
\fC;b"j {
bG"FN/vg if(nHookCount>1){
r|ZB3L|7 nHookCount--;
a""9%./B return TRUE;
t1
9f%d }
e~)4v BOOL unhooked = UnhookWindowsHookEx(hHook);
D5Sbs( if(unhooked==TRUE){
60%fva nHookCount=0;
i83Jy w,f hHook=NULL;
sl$y&C- }
(>u1O V return unhooked;
ND?"1/s }
E]&N'+T
C^'r>0 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
/<[_V/g[t? {
:+QNN< BOOL bAdded=FALSE;
.j,xh )v" for(int index=0;index<MAX_KEY;index++){
fk?!0M6d if(hCallWnd[index]==0){
X1}M_h% hCallWnd[index]=hWnd;
<W3p! HotKey[index]=cKey;
"38<14V HotKeyMask[index]=cMask;
6ZI7V!k bAdded=TRUE;
gU&+^e > KeyCount++;
2<n18-|OQ break;
OPq|4xu }
@,Dnl v|? }
v+sF0
j\P return bAdded;
n{<@-6 }
AIQ
{^: {U3jJ#K BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
\pK&gdw {
?Q=(?yR0] BOOL bRemoved=FALSE;
am.d^' for(int index=0;index<MAX_KEY;index++){
;}S_ PnwC@ if(hCallWnd[index]==hWnd){
k
75 p if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
6 mLC{X[ hCallWnd[index]=NULL;
mP15PZ HotKey[index]=0;
xA:;wV HotKeyMask[index]=0;
|p+FIr+ bRemoved=TRUE;
qR2cRepV KeyCount--;
(dNF)(wn break;
1z2v[S&pk }
IN1n^f$: }
#2Q%sE? }
%j1 7QD8 return bRemoved;
|SMigSu r` }
#>_fYjT }2BNy9q@ void VerifyWindow()
d@*dbECG {
s/~[/2[bnf for(int i=0;i<MAX_KEY;i++){
RDQ]_wsyKG if(hCallWnd
!=NULL){ im:[ViR {
if(!IsWindow(hCallWnd)){ 9%ct
hCallWnd=NULL; m^ar:mK@
HotKey=0; Xu_1r8-|=b
HotKeyMask=0; r:0RvWif
KeyCount--; Dvz 6 E
} VY~*QF~P
} =|$U`~YB
} L&NpC&>wD
} qx >Z@o
';v2ld 9
BOOL CHookApp::InitInstance() cJwe4c6.m
{ IhSXU<]
AFX_MANAGE_STATE(AfxGetStaticModuleState()); Pk5\v0vkg
hins=AfxGetInstanceHandle(); >yVrIko
InitHotkey(); ^56D)A=
return CWinApp::InitInstance(); 3#udzC
} V5h_uGOD
e>!]_B1ad
int CHookApp::ExitInstance() 5gx;Bp^_
{ 30Q77,Nsny
VerifyWindow(); g .:ZMV
UnInit(); H)*%e G~
return CWinApp::ExitInstance(); K|~!oQ
} q(s0dkrj
{t0!N]'
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file C$at9=(E6
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) R"t2=3K
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ +ZE"pA^C
#if _MSC_VER > 1000 y\iECdPU
#pragma once u5U^}<}y}
#endif // _MSC_VER > 1000 d@Bd*iI<
\Z%_dT}
class CCaptureDlg : public CDialog {~EsO1p
{ sKiy1Ww
// Construction 1#>uqUxah
public: 8BS Nm
BOOL bTray; :N<o<