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:
^f
&XQQY
.hP D$o 一、实现方法
|vwVghC Zq|I,l0+E 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
w d^': eV"h0_ox #pragma data_seg("shareddata")
YTpSHpf@ HHOOK hHook =NULL; //钩子句柄
)uIe&B
UINT nHookCount =0; //挂接的程序数目
?)?Ng} static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
;|5F[ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
wj<6kG static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
Eh;'S"{/?j static int KeyCount =0;
# E^1|: static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
fue(UMF~ #pragma data_seg()
SSg8}m5)Q dA`IEQJL 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
E7 Ul;d
3cyHfpx-W DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
p8H'{f\G .fFCC`&T BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
A*R^n}sh cKey,UCHAR cMask)
ZW8vza {
y8Z_Itlf BOOL bAdded=FALSE;
}wjw:M for(int index=0;index<MAX_KEY;index++){
"3"V3w if(hCallWnd[index]==0){
cAqLE\h hCallWnd[index]=hWnd;
vq0Tk
bzs HotKey[index]=cKey;
2dcV"lY HotKeyMask[index]=cMask;
E`0? bAdded=TRUE;
UA0Bzoky; KeyCount++;
9y8&9<# break;
]z;I_- }
Yty/3T3)e }
Mj?`j_X return bAdded;
4qbBc1,7y }
E *6Cw
l //删除热键
UWJ8amA BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
IH&|Tcf\ {
Bz-c$me1 BOOL bRemoved=FALSE;
S_4?K)n # for(int index=0;index<MAX_KEY;index++){
,~$p,ALwN7 if(hCallWnd[index]==hWnd){
~'H]jN if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Y>T-af49 hCallWnd[index]=NULL;
o.g V4% HotKey[index]=0;
f#"J]p HotKeyMask[index]=0;
{
Fb*&|-n bRemoved=TRUE;
bMu+TgAT, KeyCount--;
vHc%z$-d break;
@#>rYAb8, }
SC!RbW@3 }
#ut }
AW'0,b`v return bRemoved;
7~%?# }
3`|@H-c9 G1tY) _-8[ 0c]/bs{} DLL中的钩子函数如下:
vY}g<* t?&|8SId LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
I)6+6pm {
9dLV96 BOOL bProcessed=FALSE;
z`}qkbvi if(HC_ACTION==nCode)
*3FKt&v 0 {
2'\H\| if((lParam&0xc0000000)==0xc0000000){// 有键松开
?V.cOR`6 switch(wParam)
w\u=)3qyVV {
8)3*6+D case VK_MENU:
(9GWbB? MaskBits&=~ALTBIT;
tBWrL{xLe break;
rmm0/+jY case VK_CONTROL:
*?>T,gx} MaskBits&=~CTRLBIT;
E \EsWb break;
I@~QV@U case VK_SHIFT:
v`x.)S1 MaskBits&=~SHIFTBIT;
Tc:)-
z[o break;
@4#c&h3 default: //judge the key and send message
({)+3]x break;
|4zIfAO }
cn3\kT* for(int index=0;index<MAX_KEY;index++){
su(1<S} if(hCallWnd[index]==NULL)
rJTa continue;
F6|]4H.3Q if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
RVmh6m {
EU;9*W< SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
eHZws`W bProcessed=TRUE;
(@VMH !3 }
70nqD>M4 }
L,`LN> }
X-Kh(Z else if((lParam&0xc000ffff)==1){ //有键按下
~<5!?6Yt switch(wParam)
"|
g>'wM* {
9YyLf ; case VK_MENU:
At>DjKx]O MaskBits|=ALTBIT;
vWv" break;
T2W eE@o case VK_CONTROL:
g2ixx+`?|: MaskBits|=CTRLBIT;
,V m
< rK break;
hH3RP{'= case VK_SHIFT:
{9pZ)tB MaskBits|=SHIFTBIT;
c_pr break;
UHkMn default: //judge the key and send message
! E5HN :# break;
pa3{8x{9m }
QO~P7r|A for(int index=0;index<MAX_KEY;index++){
uyWunpT if(hCallWnd[index]==NULL)
2- h{N continue;
qgHWUwr+n if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
AKfDXy {
((;!<5-`s SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Eyqa?$R bProcessed=TRUE;
C2I_%nU Z1 }
b\!_cb~ "@ }
$( kF# }
]:- mbgW if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
M"Hf :9Rk for(int index=0;index<MAX_KEY;index++){
ZJJY8k ` if(hCallWnd[index]==NULL)
hWLA<wdb continue;
lgy<?LI\ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
!i}w~U< SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
8/cX]J //lParam的意义可看MSDN中WM_KEYDOWN部分
5Ln,{vsv }
M
FMs[+2_o }
BwpqNQN }
7S:\"A7 return CallNextHookEx( hHook, nCode, wParam, lParam );
lb3bm)@: }
s
5Qcl;} 4E+e}\r:6 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
d&Zpkbh" yx[/|nZDC4 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
7xlkZF BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
eC4[AX6e 8kIksy 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
2@],ZLa rZ$O?K LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
Of#u {
+TL%-On if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
4F:\-O {
K@]4g49A/j //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
T&bYa`f] SaveBmp();
Dml;#'IF3 return FALSE;
v ;{#Q&( }
_;y9$"A …… //其它处理及默认处理
Gb6 'n$g }
_N cR)2 u&vf+6=9Dd Hvi49c]] 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
jB2[( 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。
<'Eme g:@#@1rB6 二、编程步骤
oZgjQM$YP h(dvZ=
% 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
^{`exCwMx .~;\eW [ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
'H>^2C iM 5C]x!>kX 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
,&.!?0+ !;A\.~-!G 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
.p[ux vp
"&u@d~`-n 5、 添加代码,编译运行程序。
Wn2NMXK ^^$s%{ep" 三、程序代码
hn@08t G KV *#T20T ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
JH9J5%sp #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
S%>]q
s #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
+ &Eqk #if _MSC_VER > 1000
YD6'#( #pragma once
(w3YvG. #endif // _MSC_VER > 1000
2/^3WY1U #ifndef __AFXWIN_H__
ES7s1O$# #error include 'stdafx.h' before including this file for PCH
C,r;VyW6BI #endif
*i%d,w0+ #include "resource.h" // main symbols
~36!?&eA8 class CHookApp : public CWinApp
d7upz]K9g {
Ui W>J public:
g!|kp? CHookApp();
=dKtV.L // Overrides
:5<UkN)R( // ClassWizard generated virtual function overrides
#;yZ //{{AFX_VIRTUAL(CHookApp)
#;e:A8IQ public:
6bC3O4Rw virtual BOOL InitInstance();
x 9fip- virtual int ExitInstance();
ZY+qA //}}AFX_VIRTUAL
O^
yG?b //{{AFX_MSG(CHookApp)
I\ob7X'Xu! // NOTE - the ClassWizard will add and remove member functions here.
lymCH // DO NOT EDIT what you see in these blocks of generated code !
NXrlk //}}AFX_MSG
CD~.z7,LC DECLARE_MESSAGE_MAP()
>kVz49j };
L="}ErmK LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
>y3=| BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
)Aqtew+A& BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
h2R::/2. BOOL InitHotkey();
7{*>agQh BOOL UnInit();
gM:".Ee #endif
q 2E_A f
;n3&e0eC //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
;e *!S}C, #include "stdafx.h"
%h!B^{0 #include "hook.h"
} q8ASYNc #include <windowsx.h>
zrb}_ #ifdef _DEBUG
=7eV/3 #define new DEBUG_NEW
8d'0N #undef THIS_FILE
Wne@<+mX static char THIS_FILE[] = __FILE__;
^1.By^
$ #endif
S,he6zS #define MAX_KEY 100
{`@G+JV~Jw #define CTRLBIT 0x04
|CyE5i0 #define ALTBIT 0x02
4kx
N<] #define SHIFTBIT 0x01
'H;*W |:-] #pragma data_seg("shareddata")
evmeqQG= HHOOK hHook =NULL;
Avb\{)s+ UINT nHookCount =0;
tWcHb # static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
VOLj>w static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
gPPkT" static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
@q)d static int KeyCount =0;
P&Vv/D static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
j8sH|{H!Nq #pragma data_seg()
wibNQ`4k HINSTANCE hins;
cvL;3jRo void VerifyWindow();
[4)F f BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
=I_'.b //{{AFX_MSG_MAP(CHookApp)
|A(Iti{v // NOTE - the ClassWizard will add and remove mapping macros here.
tCt#%7J;a // DO NOT EDIT what you see in these blocks of generated code!
+ZP7{% //}}AFX_MSG_MAP
i83OOV$1J END_MESSAGE_MAP()
f/?P514h r~['VhI!;E CHookApp::CHookApp()
sW\!hW1*x {
Z%UP6% // TODO: add construction code here,
,ig/s2ZG6X // Place all significant initialization in InitInstance
$XH^~i; }
Eu3E-K@y Q~9^{sHZjP CHookApp theApp;
`R^g U]Z, LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
@6-jgw>W2 {
VIf.q)_k BOOL bProcessed=FALSE;
;O,jUiQ if(HC_ACTION==nCode)
hhvyf^o {
4*;MJ[| if((lParam&0xc0000000)==0xc0000000){// Key up
K|=A: switch(wParam)
I&5!=kR {
m1A J{cs case VK_MENU:
W(p_.p"
MaskBits&=~ALTBIT;
Ow,b^| break;
8z\xrY case VK_CONTROL:
j?QDR MaskBits&=~CTRLBIT;
J'r^/ break;
GQ
;;bcj& case VK_SHIFT:
B9S@(/"7 MaskBits&=~SHIFTBIT;
qH_Dc=~la break;
"m>81-0 default: //judge the key and send message
Vxt+]5X break;
rytyw77t( }
1o>xEWt:0K for(int index=0;index<MAX_KEY;index++){
veECfR; if(hCallWnd[index]==NULL)
47/iF97 continue;
tZo} ;|~' if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
u ^RxD^=L {
LDa1X2N SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
#g!.T g' bProcessed=TRUE;
alb.g>LNPP }
TA~{1_l }
`Q,H|hp;k; }
*VN6cSq else if((lParam&0xc000ffff)==1){ //Key down
a8Wwq?@ switch(wParam)
xgtR6E^k {
}Y4qS case VK_MENU:
-UT}/:a MaskBits|=ALTBIT;
HxI"
8A break;
c:.eGH_f case VK_CONTROL:
&%Tj/ Qx MaskBits|=CTRLBIT;
`M6)f?|$. break;
cB&:z)i4 case VK_SHIFT:
zbPqYhJzA MaskBits|=SHIFTBIT;
RD&PDXT4 break;
\73ch default: //judge the key and send message
apxph2yvS break;
9gZ$
}
`r_/Wt{g for(int index=0;index<MAX_KEY;index++)
)!T/3|C {
Xn
;AZu^'R if(hCallWnd[index]==NULL)
>(RkZ}z continue;
jc9y<{~x/ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
+ck}l2 {
.N(p=9 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
bZV/l4TU bProcessed=TRUE;
Y<8vw
d }
/a o5FL }
U/BR*Zn]* }
Tm?# M&' if(!bProcessed){
{(}By/_ for(int index=0;index<MAX_KEY;index++){
Y <qm{e if(hCallWnd[index]==NULL)
yV(\R continue;
?bu>r=oIO] if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
nQS|Lt_+ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
L/^I*p, }
?z
u8)U }
>o,TZc\ }
E4xa[iZ return CallNextHookEx( hHook, nCode, wParam, lParam );
!f6(Zho }
PUX;I0Cf Y
nZiTe@ BOOL InitHotkey()
`P ,d$H " {
t
|oR7qa{w if(hHook!=NULL){
W@!S%Y9 nHookCount++;
,7b[!#?8 return TRUE;
RpYERAgT }
cCc(fF*^ else
)\^-2[; hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
pD]OT-8 if(hHook!=NULL)
~u+9J} nHookCount++;
5/z/>D; return (hHook!=NULL);
=nHgDrA_ }
gPc=2 BOOL UnInit()
t&DEb_"De {
jF*j0PkNdb if(nHookCount>1){
29q _BR *: nHookCount--;
~F7gP{r return TRUE;
iG?[<1~ }
C"enpc_C/ BOOL unhooked = UnhookWindowsHookEx(hHook);
4xJQ!>6 if(unhooked==TRUE){
>yh2Lri nHookCount=0;
&iVs0R hHook=NULL;
>@AB<$A }
RCLeA=/N@0 return unhooked;
C{wEzM: }
u>/ TE \5cpFj5% BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
g$o&Udgs {
;6hOx(>`= BOOL bAdded=FALSE;
2)~> R for(int index=0;index<MAX_KEY;index++){
(_{yB[z>` if(hCallWnd[index]==0){
'[O;zJN; hCallWnd[index]=hWnd;
h `.& f HotKey[index]=cKey;
y18Y:)DkL HotKeyMask[index]=cMask;
&G$Ucc
` bAdded=TRUE;
KCDE{za KeyCount++;
P
L+sR3bR break;
s&J]zb` }
R_xRp&5 }
/|#fejPh return bAdded;
HE_8(Ms;8 }
Vs{|xG7WD v74&BL]a BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
0Fr?^3h {
G9@0@2aY8 BOOL bRemoved=FALSE;
*k>n<p3dd for(int index=0;index<MAX_KEY;index++){
Q)z8PQl O if(hCallWnd[index]==hWnd){
BDZ?Ez\Sg if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
xi;`ecqS< hCallWnd[index]=NULL;
RY*U"G0#w HotKey[index]=0;
5i{j' {_(8 HotKeyMask[index]=0;
EDs\,f} bRemoved=TRUE;
_t}WsEQ+P KeyCount--;
B48={ break;
,wdD8ZT'Ip }
hwNf~3eJk }
h3@v+Z<} }
HiJE}V;Vq return bRemoved;
P}`H ~N~ }
B^jc3 VsR J!7MZLb void VerifyWindow()
|IUWF%~^$+ {
U|j`e5) for(int i=0;i<MAX_KEY;i++){
"8zDbdK if(hCallWnd
!=NULL){
^L&iR0
if(!IsWindow(hCallWnd)){ , SnSW-P
hCallWnd=NULL; K,:N
HotKey=0; 63x?MY6
HotKeyMask=0; '>C5-R:O
KeyCount--; yJe>JK~)
} Ok\7y-w^
} njA#@fU
} Nu~lsWyRI5
} T37XBg H
%BB%pC
BOOL CHookApp::InitInstance() TrR8?-
{ _/<x
AFX_MANAGE_STATE(AfxGetStaticModuleState()); j^2j&Ta
hins=AfxGetInstanceHandle(); {+Cy U!O
InitHotkey(); QoH6
return CWinApp::InitInstance(); @49S`
} KRKCD4
&~U ] ~;@
int CHookApp::ExitInstance() ('p5:d
{ P J[`|
VerifyWindow(); R0
UnInit(); K@w{"7}
return CWinApp::ExitInstance(); {3vNPQJ
} fL7xq$K
0% I=d
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file pIKPXqA
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) ,UdVNA
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ D=&Me=$
#if _MSC_VER > 1000 4)o
#pragma once $\y'IQ%
#endif // _MSC_VER > 1000 gjzuG<7m
7EO_5/cY
class CCaptureDlg : public CDialog cq4Ipe
{ 6<(.4a?
// Construction fXQNHZ|4
public: }U5yQ%N
BOOL bTray; 'K,:j 388
BOOL bRegistered; %sQ^.` 2
BOOL RegisterHotkey(); 3=]sLn0L
UCHAR cKey; G+\GaY[
UCHAR cMask; 0'?L#K
void DeleteIcon(); UN<]N76!
void AddIcon(); $z*'fXg
UINT nCount; T 0rGM
void SaveBmp(); yY&I