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:
4/cUd=>Z
|%Pd*yZA 一、实现方法
%qNT<>c y$'(/iyz 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
ApR>b% *{6{ZKM #pragma data_seg("shareddata")
Kx7s
d i HHOOK hHook =NULL; //钩子句柄
DYx3NDX7 UINT nHookCount =0; //挂接的程序数目
it \3- static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
wMr*D['" # static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
ve<D[jQsk static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
rjz$~(&m6 static int KeyCount =0;
}Dp/K4 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
|<gYzbq #pragma data_seg()
741Sd8 M]
7# 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。
/GRkQ", WTbq)D(&[_ 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:
E&9BeU
a# az/NZlJhT BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
HW"@~-\ cKey,UCHAR cMask)
22$M6Qof]n {
"&W80,O3 BOOL bAdded=FALSE;
{W,&jC for(int index=0;index<MAX_KEY;index++){
kIrb;bZ+l if(hCallWnd[index]==0){
].w~FUa hCallWnd[index]=hWnd;
h8'`g 0 HotKey[index]=cKey;
bL-+ HotKeyMask[index]=cMask;
dD ?ZF6 bAdded=TRUE;
b*(74 >XY KeyCount++;
E+)3n[G break;
;LD!eWSK, }
5o2w)<d! }
4d-f6iiFV return bAdded;
B:;$5PUTc }
NCL!| //删除热键
'*lVVeSiFw BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
>cw%ckE {
,v ,#f
. BOOL bRemoved=FALSE;
Qh3BI?GZ'3 for(int index=0;index<MAX_KEY;index++){
}LeizbU if(hCallWnd[index]==hWnd){
u0p[ltJ, if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Ce_k&[AJF hCallWnd[index]=NULL;
qjDt6B^RO HotKey[index]=0;
KDxqz$14- HotKeyMask[index]=0;
-c4g;;% bRemoved=TRUE;
mBN+c9n/ KeyCount--;
:J6 xYy$ break;
$raq,SP }
%^Zu^uu }
S\io5|P }
RqB 8g return bRemoved;
4 ))Z Bq? }
A*^aBWFR JCFiKt9n Dk%+|c DLL中的钩子函数如下:
}l"pxp1K P8[rp LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Sq:,6bcG {
6--t6>5 BOOL bProcessed=FALSE;
\w#)uYK{i_ if(HC_ACTION==nCode)
+adwEYRrr {
FNlS)Bs if((lParam&0xc0000000)==0xc0000000){// 有键松开
4M*Z1 switch(wParam)
?*LVn~y {
~
kwS` case VK_MENU:
q<[m(]: MaskBits&=~ALTBIT;
_59f.FsVR break;
ANWfRtiU# case VK_CONTROL:
z>]P_E~`} MaskBits&=~CTRLBIT;
nEHmiG break;
;-kC&GZf case VK_SHIFT:
R`KlG/Tk MaskBits&=~SHIFTBIT;
` {/"?s| break;
?mwa6] default: //judge the key and send message
Y#[xX2z9 break;
D,\hRQ }
T_)G 5a for(int index=0;index<MAX_KEY;index++){
*(E]]8o if(hCallWnd[index]==NULL)
)s N}ClgJ continue;
}i._&x`): if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
_$+BYK@ {
&8\6%C SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
`NySTd)\ bProcessed=TRUE;
#?"^: ,Y }
OMfw# }
,J(shc_F }
Y6G`p else if((lParam&0xc000ffff)==1){ //有键按下
3!M|Sf<s switch(wParam)
'C7$,H' {
70-nAv case VK_MENU:
hh!4DHv MaskBits|=ALTBIT;
<c% break;
<P~pn!F} case VK_CONTROL:
vN&(__3(( MaskBits|=CTRLBIT;
;oCSKY4 break;
4OeH}@ a case VK_SHIFT:
v`hn9O MaskBits|=SHIFTBIT;
[>D5(O break;
|"g+p)A default: //judge the key and send message
IN_O!c0e break;
Z H2 }
}2h! for(int index=0;index<MAX_KEY;index++){
XM f>B| if(hCallWnd[index]==NULL)
LEuDDJ- continue;
x3:d/>b if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
dWTc3@xd {
xc}kDpF=g SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
>N~orSw% bProcessed=TRUE;
s~06%QEG }
`{%ImXQF }
j-#h^3l1? }
BD-
c<K" if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
Dy&{PeE! for(int index=0;index<MAX_KEY;index++){
5[LDG/{Tys if(hCallWnd[index]==NULL)
/Z~5bb( continue;
LNcoTdv}k if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
=%SH2kb SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
{4 {X`$ //lParam的意义可看MSDN中WM_KEYDOWN部分
vM?,#:5 }
<ivq}(%72 }
_Un*x5u2O }
?f= ~Pn+ return CallNextHookEx( hHook, nCode, wParam, lParam );
CC)Mws+2 }
VpX*l3 j^.|^q<Y 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:
:28[k~.bo f}EsS BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
RK/>5 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Vkfc&+ OP|X- 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:
b,x$wP+ b#-=Dbe LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
?)g [Xc;K {
/ hg)=p if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
r{{5@ {
.P#t"oW} //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
+
B<7]\\M SaveBmp();
_
h/:r1 return FALSE;
xb2j
|KY7 }
.qLXjU …… //其它处理及默认处理
Bk]
`n'W }
^HU>fkSk CF6qEG6 :Wihb#TO) 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。
>>c%Ic MoXai0d% 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。
U8{^-#(Uz _hgGF9 二、编程步骤
ydMhb367| f\FqZ?w 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";
0v#p4@Z /IlO 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
_FU}IfG>t mA#;6?6 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;
MP_/eC ; XZ2 ji_D 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;
w\M"9T fZ(k"*\MZ 5、 添加代码,编译运行程序。
XP[~ :+ r?9".H 三、程序代码
3e>U(ES e~SRGyIww ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
r)B55;*Fh #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
v|dt[>G #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
b'I@TLE') #if _MSC_VER > 1000
3lbGG42: #pragma once
<E:_9#Z0sc #endif // _MSC_VER > 1000
7X8*7'.2 #ifndef __AFXWIN_H__
#7"";"{z| #error include 'stdafx.h' before including this file for PCH
J\FLIw4 #endif
dGUiMix{N #include "resource.h" // main symbols
WHqw=!G class CHookApp : public CWinApp
ps^["3e {
*uSlp_;kB public:
ZENblh8fs CHookApp();
+Ht(_+To1 // Overrides
T+PERz( // ClassWizard generated virtual function overrides
~>Y^?l //{{AFX_VIRTUAL(CHookApp)
Q3'P<"u public:
q;#bFPh virtual BOOL InitInstance();
-v:3#9uX) virtual int ExitInstance();
,kUg"\_k //}}AFX_VIRTUAL
,4k3C#!.i //{{AFX_MSG(CHookApp)
@vL0gzE?nB // NOTE - the ClassWizard will add and remove member functions here.
y4VO\N!
// DO NOT EDIT what you see in these blocks of generated code !
!hE F.S //}}AFX_MSG
$KBW{ DECLARE_MESSAGE_MAP()
`<#O8,7` };
N!Xn)J LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
"([lkn BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
3m~,6mQ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
>|0I\{C BOOL InitHotkey();
1ed^{Wa4$9 BOOL UnInit();
{suQ"iv #endif
t.
HwX9 HdyE`FY \ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
]bbP_n8 #include "stdafx.h"
3NdO3-~) #include "hook.h"
ti 3S'K0t #include <windowsx.h>
}S4+1
U3 #ifdef _DEBUG
%L$?Mey #define new DEBUG_NEW
i ~)V>x #undef THIS_FILE
4pZKm-dM^ static char THIS_FILE[] = __FILE__;
>;#rK@*& #endif
Y5P9z{X= #define MAX_KEY 100
ERIF#EY #define CTRLBIT 0x04
WqS$C;]% #define ALTBIT 0x02
rCb$^(w{7 #define SHIFTBIT 0x01
Y/LS(b* #pragma data_seg("shareddata")
"Bz#5kqnl HHOOK hHook =NULL;
VA`VDUG, UINT nHookCount =0;
hu7oJ H static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
~jzT;9: static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
Iu(]i?Y static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
ZXf&pqmG static int KeyCount =0;
fF2]7: static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
mRt/d #pragma data_seg()
` +)Bl%* HINSTANCE hins;
jk Aru_C void VerifyWindow();
06`caG|]-M BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
r9<#R=r)}J //{{AFX_MSG_MAP(CHookApp)
!|
q19$ // NOTE - the ClassWizard will add and remove mapping macros here.
roBbo // DO NOT EDIT what you see in these blocks of generated code!
mE'HRv //}}AFX_MSG_MAP
H_ NoW END_MESSAGE_MAP()
D( y
c #TV #* CHookApp::CHookApp()
o=PW)37> {
Q'Uv5p"X // TODO: add construction code here,
7UqDPEXU]` // Place all significant initialization in InitInstance
4QYStDFe }
=L;g:hc< 7mn&w$MS4: CHookApp theApp;
sQ&<cBs2 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
)`2ncb
{
-
^Y\'y2 BOOL bProcessed=FALSE;
:G=ol2Q if(HC_ACTION==nCode)
|oQhtk8. {
m 0Uu2Z4 if((lParam&0xc0000000)==0xc0000000){// Key up
JdUI:( switch(wParam)
9H53H"5q {
KM[&WT case VK_MENU:
a/rQ@ c> MaskBits&=~ALTBIT;
+i}uRO break;
"*TP@X?@f case VK_CONTROL:
dz/3=0
MaskBits&=~CTRLBIT;
bIzBY+P break;
&'/bnN +R case VK_SHIFT:
y'<5P~W!a MaskBits&=~SHIFTBIT;
P,#l~ \ break;
s!]QG default: //judge the key and send message
LG{50sP` break;
$O fZp<M }
.&Sjazk0XO for(int index=0;index<MAX_KEY;index++){
+(`.pa z@ if(hCallWnd[index]==NULL)
^* CKx continue;
@wVDe\% , if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
kX*.BZI}C {
k9&W0$I# SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
.3>q3sS bProcessed=TRUE;
e:.D^GFi
}
];eJ'# }
d"a\`# }
!u/c'ZLZ> else if((lParam&0xc000ffff)==1){ //Key down
i-4?]h k switch(wParam)
CUft {
@Y ?p-& case VK_MENU:
5kHU'D MaskBits|=ALTBIT;
cnDF`7xrT break;
31F^ 38 case VK_CONTROL:
DD6K[\ MaskBits|=CTRLBIT;
n"vO?8Sx break;
6aWNLJ@ case VK_SHIFT:
V<U9Pj^?^ MaskBits|=SHIFTBIT;
q AsTiT6r break;
`'9t^6mk default: //judge the key and send message
5!57<n break;
n:}'f-
:T }
er@.<Dc for(int index=0;index<MAX_KEY;index++)
c'Q.2^w^ {
$J]NWgXl@ if(hCallWnd[index]==NULL)
YWDd[\4 continue;
&x@N5j5Q if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
sqj8I"<` {
R[#B|$ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
R$"> bProcessed=TRUE;
KB{/L5 }
n8q%>.i7 }
Z5*O\kJv }
/<J5?H if(!bProcessed){
(m')dSZ for(int index=0;index<MAX_KEY;index++){
#?Ob->v if(hCallWnd[index]==NULL)
YdYaLTz continue;
qy-Hv6oof if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
%4/X;w\3 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
:Z6l)R+V }
}!WuJz" }
WpkCFp }
Hx9lQ8 return CallNextHookEx( hHook, nCode, wParam, lParam );
@[5] ?8\o }
)X6I#q8 E<
pO!P BOOL InitHotkey()
]XWtw21I1 {
j k])S~xl? if(hHook!=NULL){
ph3dm\U. nHookCount++;
qIO)<5\[%d return TRUE;
{!pYQ|# }
x139Ckn else
= d !YM6G hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
C`aUitL} if(hHook!=NULL)
OjK+`D_C nHookCount++;
R1/mzPG return (hHook!=NULL);
y p pZ@ }
vtq47i BOOL UnInit()
WmblY2 {
|e2s{J2 if(nHookCount>1){
fh&Q(:ZU nHookCount--;
!6J+# return TRUE;
nd h\+7 }
pQ`S%]k.< BOOL unhooked = UnhookWindowsHookEx(hHook);
't475?bY if(unhooked==TRUE){
I.1(qbPkF+ nHookCount=0;
@[;$R@M_3 hHook=NULL;
Eq5X/Hx }
0}\8,U return unhooked;
}jL4F$wC }
ItG|{Bo n&E/{o( BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
"ZG2olOqLI {
[t]q#+Zs BOOL bAdded=FALSE;
Jx8DVjy for(int index=0;index<MAX_KEY;index++){
Z}>+!Z if(hCallWnd[index]==0){
)2bbG4:N hCallWnd[index]=hWnd;
|YrvY1d! HotKey[index]=cKey;
wR9gx-bE
4 HotKeyMask[index]=cMask;
0fa8.g#I$ bAdded=TRUE;
vARZwIu^D KeyCount++;
N&W7g#F break;
(y2P." }
.j`8E^7< }
~0 L:c&V return bAdded;
02po; }
9}11>X 6/|"y BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
uJJP<mDgA {
DjiWg(X BOOL bRemoved=FALSE;
=fI0q7]ndz for(int index=0;index<MAX_KEY;index++){
!6*4^$i#o if(hCallWnd[index]==hWnd){
q/3co86c if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
?WrL<?r)}U hCallWnd[index]=NULL;
:;o?d&C HotKey[index]=0;
tsf!Q HotKeyMask[index]=0;
a&gf0g;@I bRemoved=TRUE;
>soSOJ[ KeyCount--;
m8&XW2S break;
o q cu<