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:
yTwv2l;U
NS@j`6/U 一、实现方法
W"+*%x z9pv| 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:
pb1/HhRR^n Bs(\e^} #pragma data_seg("shareddata")
{^2``NYM_ HHOOK hHook =NULL; //钩子句柄
J`a$"G B. UINT nHookCount =0; //挂接的程序数目
[ !/u, static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
-hw^3Af static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
^{nf0 )56c static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
.)o<'u@Ri static int KeyCount =0;
&{NN!X static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
TJ8IYo|
D #pragma data_seg()
Cqy84!Z< z[X>>P3<n 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。
p'fq&a+ rk:^^r>5Qi 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:
#qY`xH'> m`gH5vQa BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
nI.K|hU:P cKey,UCHAR cMask)
;`',M6g {
fVx<f.xuW BOOL bAdded=FALSE;
^.)oQo SE for(int index=0;index<MAX_KEY;index++){
4Ra if(hCallWnd[index]==0){
<VI.A" Qk~ hCallWnd[index]=hWnd;
O_}R~p HotKey[index]=cKey;
7p*PDoM6` HotKeyMask[index]=cMask;
=aZgq99 bAdded=TRUE;
_0dm?= KeyCount++;
-J*BY2LU3f break;
jWk1FQte }
/ap3>xkt }
V
.+ mK|) return bAdded;
&{E1w<uv }
3gtQS3$4s //删除热键
Qc1NLU9: BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
hB/4.K ]8 {
ScOiOz:Ha BOOL bRemoved=FALSE;
n4 A_vz for(int index=0;index<MAX_KEY;index++){
7u7`z% if(hCallWnd[index]==hWnd){
Nki08qZ[ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ZLm?8g6- hCallWnd[index]=NULL;
E;m]RtvH HotKey[index]=0;
DmzK* O{ HotKeyMask[index]=0;
8Ld{Xg bRemoved=TRUE;
ZNWo:N8; KeyCount--;
q,S[[{(" break;
b7-M'-Km0_ }
CVUA7eG+ }
_v=S4A#tF }
9~3;upWu! return bRemoved;
W^dk: }
DzZEn]+zt 3XykIj1 GZ=7)eJ~< DLL中的钩子函数如下:
c,@&Z#IZ` YA+jLy6ZL LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
a
]~Rp {
1f}YKT BOOL bProcessed=FALSE;
ky4;7RK if(HC_ACTION==nCode)
au=A+ {
2Xw=kw u if((lParam&0xc0000000)==0xc0000000){// 有键松开
rF@njw@ switch(wParam)
Z%&$_-yJ {
JRgrg case VK_MENU:
6=pE5UfT MaskBits&=~ALTBIT;
FS'|e?WU break;
%_P[
C}4 case VK_CONTROL:
qb$&BZj]| MaskBits&=~CTRLBIT;
gm^j8B break;
*s JT\J$D[ case VK_SHIFT:
z:Y
Z]
MaskBits&=~SHIFTBIT;
^Uq%-a break;
we("#s1= default: //judge the key and send message
#}xw
*)3 break;
xF8U )j! }
!l(D0 C for(int index=0;index<MAX_KEY;index++){
Wg5<@=x!G if(hCallWnd[index]==NULL)
Ei HQ&u* continue;
\k4em{K if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
'^|u\$&U {
zH5pe SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
zi^?9n), bProcessed=TRUE;
Cg8s9qE? }
OA7YWk<K }
W5*Kq^6Pd }
eG_@WLxwD else if((lParam&0xc000ffff)==1){ //有键按下
P:#KBF;a switch(wParam)
wPE\?en {
\; voBU case VK_MENU:
.vnQZ*6 MaskBits|=ALTBIT;
B7QRG0 break;
^?V9 case VK_CONTROL:
RVN;j4uMg MaskBits|=CTRLBIT;
| LXVf break;
~tc,p case VK_SHIFT:
Jn&^5,J]F8 MaskBits|=SHIFTBIT;
drQI@sPp break;
^`S.Mw. default: //judge the key and send message
XfQK
kol break;
OZR{+YrB^ }
yU"lJ>Eh}} for(int index=0;index<MAX_KEY;index++){
rT|wZz9$@ if(hCallWnd[index]==NULL)
cx~XG continue;
^)E#
c if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
} *jmW P {
~H c5M5m SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
O?`_RN4l bProcessed=TRUE;
G,}"}v: }
Ya&\ b 6 }
P,rD{ 0~ }
~f:"Q(f+ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
l*w*e.ezQ for(int index=0;index<MAX_KEY;index++){
O)!S[5YI if(hCallWnd[index]==NULL)
Aw]kQ\P& continue;
FL{$9o\@ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
#O lPnP 2 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
I}+9@d //lParam的意义可看MSDN中WM_KEYDOWN部分
gW-mXb }
c2u*<x }
g3
opN>W }
^kK% 8 u return CallNextHookEx( hHook, nCode, wParam, lParam );
+~V)&6Vn }
aHdQi,=z R2A#2{+H 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
M0$_x~ jp7cPpk:LG BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
W]5Hc|!^^ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
A">R-1R ffMk.SqI 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:
@A|#/]S1 ^'n;W<\p) LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
w6h*dh$w {
_C)\X(; if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
z%1& t4$ {
\YSprXe //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
CFUn1^?0 SaveBmp();
@*E=O | return FALSE;
X/_89<& }
vY7@1_" …… //其它处理及默认处理
*,zrg%8 }
G+&pq 4peRbm + KaVvf 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。
z+{xW7 91-[[< 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。
^H -a@QM +`iJ+ 二、编程步骤
]:;dJc' 6Jq3l_ 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";
:cf#Tpq" kS?CKd9by 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
eL<jA9cJ9 I9dX\w} 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;
LpL$=9 NTEN 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
UmArl)R/ a;v4R[lQ 5、 添加代码,编译运行程序。
%WC^aKfY UZs'H"K 三、程序代码
[k0/ZfFwV uQ&> Wk ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
t 4VeXp6 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
Y;'SD{On #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
`H 'wz7 #if _MSC_VER > 1000
B*Ey&DAV #pragma once
]1pB7XL #endif // _MSC_VER > 1000
:wN!E{0j #ifndef __AFXWIN_H__
<s7cCpUFP #error include 'stdafx.h' before including this file for PCH
c%bzrYQvA; #endif
0qIg:+l+ #include "resource.h" // main symbols
m;A[2 6X class CHookApp : public CWinApp
7>f"4r_r6< {
O;5lF public:
lD, ~% CHookApp();
nt+OaXe5D // Overrides
Br15S};Ce // ClassWizard generated virtual function overrides
!A1~{G2VL_ //{{AFX_VIRTUAL(CHookApp)
+jK-k_ public:
H
cyoNY virtual BOOL InitInstance();
?3 k_YN" virtual int ExitInstance();
(Q @'fb9z //}}AFX_VIRTUAL
[3I|MZ //{{AFX_MSG(CHookApp)
7(oA(l1V // NOTE - the ClassWizard will add and remove member functions here.
rmo\UCD // DO NOT EDIT what you see in these blocks of generated code !
Z1:%AqxP //}}AFX_MSG
N>,`TsUwW DECLARE_MESSAGE_MAP()
[0hahR };
p:K%-^ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
F>3 o0ke} BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
oP9 y@U BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
~#jiX6<I BOOL InitHotkey();
aidQ,(PDj BOOL UnInit();
-B9e&J
{K #endif
vV*J;%MO HZZZ [km //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
i>]PW|]
#include "stdafx.h"
|/^S%t6* #include "hook.h"
)5LT!14 #include <windowsx.h>
lux
g1> #ifdef _DEBUG
>X
eXd{$ #define new DEBUG_NEW
DyCzRkH #undef THIS_FILE
z<mN-1PM7& static char THIS_FILE[] = __FILE__;
abm 3q!a- #endif
k&%i+5X #define MAX_KEY 100
c9fz x #define CTRLBIT 0x04
K%+4M#jj5 #define ALTBIT 0x02
R:YVmqd #define SHIFTBIT 0x01
\20}/& #pragma data_seg("shareddata")
\U]K!K= HHOOK hHook =NULL;
Q,^/Lm|]k UINT nHookCount =0;
yDKH;o static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
WV.hQX9P static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
iiMS3ueF static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
=g!Pw] static int KeyCount =0;
Xi) ;dcNJ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
?z#*eoPr #pragma data_seg()
vN\[2r%S HINSTANCE hins;
sdg2^] | void VerifyWindow();
H~nX!sO BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
cI@qt>& //{{AFX_MSG_MAP(CHookApp)
)Yy5u'} // NOTE - the ClassWizard will add and remove mapping macros here.
S-q"'5> // DO NOT EDIT what you see in these blocks of generated code!
o]Ne|PEpO //}}AFX_MSG_MAP
ZxSFElDD]E END_MESSAGE_MAP()
Cj-&L< ,++HiYOG}e CHookApp::CHookApp()
)Bn
}|6` {
Wn+s:ov // TODO: add construction code here,
*>:phs~r{ // Place all significant initialization in InitInstance
'(3 QyCD }
O5-GrR^yt 7Qd$@ m CHookApp theApp;
\z.bORy LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
j
[lS.Lb {
z6@8IszU BOOL bProcessed=FALSE;
3pvqF,"~D if(HC_ACTION==nCode)
x;yvv3-$ {
ptT-{vG if((lParam&0xc0000000)==0xc0000000){// Key up
5s3QN{h8 switch(wParam)
Eej
Lso#\ {
56<U xIa~ case VK_MENU:
Itr4Pr MaskBits&=~ALTBIT;
NJsaTBT break;
f^1J_}cL case VK_CONTROL:
Any y MaskBits&=~CTRLBIT;
Tph^o^ break;
GD.Ss9_h1 case VK_SHIFT:
u:|^L]{ MaskBits&=~SHIFTBIT;
T{Xd > break;
N? Jy default: //judge the key and send message
;LP3 break;
!38KHq^|& }
v%cCJ SO# for(int index=0;index<MAX_KEY;index++){
lM4 Z7mT / if(hCallWnd[index]==NULL)
|3e+ K. continue;
63l&
ihj if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
k5aB|xo {
o=7,U/{D! SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
)S+fc= bProcessed=TRUE;
N!~]D[D }
@!dIa1Q" }
_"@:+f, }
a r8iuwfZ else if((lParam&0xc000ffff)==1){ //Key down
f#:3TJV switch(wParam)
YOLzCnI4 {
H@@ 4n%MK case VK_MENU:
~)_Nh MaskBits|=ALTBIT;
K0(
S%v|,} break;
ds!nl1 case VK_CONTROL:
nk tGO MaskBits|=CTRLBIT;
dVB#Np break;
,==_u case VK_SHIFT:
o]&q'>Rf MaskBits|=SHIFTBIT;
{Cm!5Q Yy break;
@ U=y}vi8 default: //judge the key and send message
34!.5^T break;
!gW`xVGv }
+^(_S9CO for(int index=0;index<MAX_KEY;index++)
AA[1[ {
/gF)msUF if(hCallWnd[index]==NULL)
0yC~"u[N Y continue;
N2s"$Ttq if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
;=0mL, {
F_:zR,P%# SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
G(wK(P0j bProcessed=TRUE;
btEyvqs~X }
r2\%/9uO }
>&;J/ME }
2{=D)aC$f if(!bProcessed){
id9QfJ9t for(int index=0;index<MAX_KEY;index++){
7<]&pSt= if(hCallWnd[index]==NULL)
c>D~MCNxg continue;
C <:g"F:k if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
,V
52Fj SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
dj(&"P }
n(Nu }
Kt*b)
< }
7I w^ return CallNextHookEx( hHook, nCode, wParam, lParam );
/Q@4HV }
3LfF{ED@ DDkN3\w BOOL InitHotkey()
X8Z) W?vu {
XlF ,_ if(hHook!=NULL){
j;}-x1R nHookCount++;
BN]o!Y return TRUE;
0-uj0"r` }
P<R^eLZ<& else
rR@]`@9 hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
0(+<uo~6p1 if(hHook!=NULL)
@xo8"kl nHookCount++;
)wjpxr return (hHook!=NULL);
d>F7i~W }
I(VqtC:K. BOOL UnInit()
.?NfV%vv {
%_:L_VD@ if(nHookCount>1){
Y_n/rD> nHookCount--;
NqF*hat return TRUE;
ASi2;Q_{_ }
y g(Na BOOL unhooked = UnhookWindowsHookEx(hHook);
<#BK(W~$ if(unhooked==TRUE){
dl=)\mSFjF nHookCount=0;
xS@jV6E~ hHook=NULL;
r+%3Y:dZE }
+?6]Vu&|f return unhooked;
NaoOgZ? }
M)K!!Jqh }!fIY7gv BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
J ##a;6@ {
_s#J\!F BOOL bAdded=FALSE;
]v:,<=S for(int index=0;index<MAX_KEY;index++){
uHquJQ4 if(hCallWnd[index]==0){
vh2/d.MO hCallWnd[index]=hWnd;
v,Kum<oi? HotKey[index]=cKey;
t5l<Lm) HotKeyMask[index]=cMask;
(&*Bl\YoX bAdded=TRUE;
g,YF$:e KeyCount++;
)2E vZn break;
IG}yGGn }
fGj66rMGw }
?8grK return bAdded;
;LC|1_ ' }
3?aM\z; Fi+DG?zu BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
G@D8[ {
#('R`~ BOOL bRemoved=FALSE;
!|VtI$I>x for(int index=0;index<MAX_KEY;index++){
FDiDHOR if(hCallWnd[index]==hWnd){
s0_HMP x if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
y<IHZq`C3 hCallWnd[index]=NULL;
yAGQD[ih HotKey[index]=0;
H]V(qq{ HotKeyMask[index]=0;
l8M}82_ bRemoved=TRUE;
}<2|6 { KeyCount--;
yp]vDm break;
Pj56,qd>s }
7dB_q}< }
nRq[il0 `i }
ZrP
8/> return bRemoved;
Qe7
SH{ }
[G+@[9hn% ,,EG"Um6 void VerifyWindow()
PCDvEbpG {
&j'k9C2p for(int i=0;i<MAX_KEY;i++){
WzdlrkD if(hCallWnd
!=NULL){ e=jtF"&
if(!IsWindow(hCallWnd)){ (Ww
SisC~
hCallWnd=NULL; +=L+35M
HotKey=0; m=pH G
HotKeyMask=0; #\ ="^z6
KeyCount--; us8ce+
} \8{Tj54NA
} N1n\tA?
} `yhc,5M
} a(JtGjTf&
3!?QQT,!)
BOOL CHookApp::InitInstance() Z>NA 9:
{ URh5ajoR%
AFX_MANAGE_STATE(AfxGetStaticModuleState()); KJ-Q$
M
hins=AfxGetInstanceHandle(); x1CMW`F
InitHotkey(); x41 t=E](
return CWinApp::InitInstance(); *:l$ud
} )B@&q.2B=
bx" .<q (
int CHookApp::ExitInstance() phwq#AxQ
{ lm'.G99{
VerifyWindow(); Gv(n2r
UnInit(); G<*h,'B
return CWinApp::ExitInstance(); kl&_O8E+K
} ,*p(q/kJh~
b DF_
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file !\&4,l(
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) "bjbJC&T
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ E?mW4?
#if _MSC_VER > 1000
q,'~=Y5
#pragma once 8wS9%+
#endif // _MSC_VER > 1000 %N<>3c<8P
4T<dI6I0
class CCaptureDlg : public CDialog KkHlMwv
{ XoiZ"zE
// Construction @qsOWx`l$
public: C2%Yr y
BOOL bTray; qkyYt#4E
BOOL bRegistered; l)0yv2[h
BOOL RegisterHotkey(); Au?(_*/0
UCHAR cKey; l}Vg;"1'J
UCHAR cMask; w?c~be$
void DeleteIcon(); A`b
)7+mB
void AddIcon(); ,H su;I~
UINT nCount; C_hIPMU=
void SaveBmp(); gkv,Om
CCaptureDlg(CWnd* pParent = NULL); // standard constructor xm<sH!,j
// Dialog Data z;i4F.p
//{{AFX_DATA(CCaptureDlg) 4b$m\hoN
enum { IDD = IDD_CAPTURE_DIALOG }; &[}5yos
r
CComboBox m_Key; .rbKvd?-}
BOOL m_bControl; gq?~*4H
BOOL m_bAlt; 3nkO+qQ
BOOL m_bShift; ok9G 9|HA
CString m_Path; 9\NP)Vm$^
CString m_Number; 0EP8MR SR
//}}AFX_DATA $S!WW|9j.
// ClassWizard generated virtual function overrides xZ&S7G1