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:
`'tw5}
R'a5,zEo/ 一、实现方法
F.* snF (J) Rs`_ 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:
ezNE9g xF :poi #pragma data_seg("shareddata")
zI*/u)48 HHOOK hHook =NULL; //钩子句柄
PtVNG UINT nHookCount =0; //挂接的程序数目
t+TbCe static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
)Q pP1[ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
:Y)kKq d static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
=Q8^@i4[&D static int KeyCount =0;
c6}xnH static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
"T=3mv%S #pragma data_seg()
|@n{tog+- :J)lC = 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。
ch2e#Jf8 DF&jZ[## 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:
dXcMysRc%& 3B_} : BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
4Hd@U&E cKey,UCHAR cMask)
2|_Jup {
T`2fPxM:cZ BOOL bAdded=FALSE;
PXQ9P<m for(int index=0;index<MAX_KEY;index++){
&Bdt+OQ ; if(hCallWnd[index]==0){
<raqp Oo& hCallWnd[index]=hWnd;
y<LwrrJ> HotKey[index]=cKey;
jU9zCMyNF HotKeyMask[index]=cMask;
}_D5, k bAdded=TRUE;
Iy 8E$B; KeyCount++;
0 VgnN break;
mWFZg.#? }
So]FDd }
9+;f1nV return bAdded;
^OcfM_4pN }
`"-!UkD+ //删除热键
"=RoI BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
mUY:S
| {
,Vn]Ft?n BOOL bRemoved=FALSE;
.j4ziRa- for(int index=0;index<MAX_KEY;index++){
]j#$. $q if(hCallWnd[index]==hWnd){
71m-W#zyA if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
!Z2n;.w hCallWnd[index]=NULL;
V6!73 iY HotKey[index]=0;
~q%9zO' HotKeyMask[index]=0;
#RIfR7`T bRemoved=TRUE;
<{).x6 KeyCount--;
(7#lN break;
EqDYQ
7 }
HG6{`i }
[/,6O }
fvAV[9/- return bRemoved;
Ch!Q? 4 }
c\rbLr}l) e/#&5ISk ?GfA;O DLL中的钩子函数如下:
(pK4i5lT h
swMy LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Tb6x@MorP {
*A9{H>Vq BOOL bProcessed=FALSE;
+Y^F>/ 4=Y if(HC_ACTION==nCode)
#CP, \G {
`; %aQR if((lParam&0xc0000000)==0xc0000000){// 有键松开
_89G2)U=C switch(wParam)
fQA)r {
umrI4.1c case VK_MENU:
2o5<nGn MaskBits&=~ALTBIT;
A,[m=9V break;
RV*Zi\-X case VK_CONTROL:
fJlN'F7 MaskBits&=~CTRLBIT;
MAo,PiYb break;
&!~n=]*sz case VK_SHIFT:
`.-k%2?/ MaskBits&=~SHIFTBIT;
m@2xC,@ break;
Bw7:ry default: //judge the key and send message
Id
7 break;
cMk%]qfVo8 }
C`<} nx1 for(int index=0;index<MAX_KEY;index++){
{:8[Mdf if(hCallWnd[index]==NULL)
TUn@b11 continue;
")gCA:1- if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
$^aXVy5p {
3Qr!?=nf SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
&rWJg6/ bProcessed=TRUE;
&Gwh<%=U }
l"!;Vkg.5 }
KgAX0dM }
s H[34gCh; else if((lParam&0xc000ffff)==1){ //有键按下
~{!!=@6 switch(wParam)
RtM.}wv; {
@Iatlz*W case VK_MENU:
Elk$9 << MaskBits|=ALTBIT;
BD+~8v break;
gUtbCqDS case VK_CONTROL:
I}A#*iD MaskBits|=CTRLBIT;
|OT%,QT| break;
;mxT>|z case VK_SHIFT:
OHvzK8 MaskBits|=SHIFTBIT;
W>IKy# break;
Ri0+nJ6 default: //judge the key and send message
*4VP5]! break;
rz7b%WY }
1T?%i for(int index=0;index<MAX_KEY;index++){
LKY
Q? if(hCallWnd[index]==NULL)
"G)?
E| continue;
AG0x) if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
FMr$cKvE]W {
[B<{3*R_ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
]F-6KeBc bProcessed=TRUE;
9'aR-tFun; }
yiA\$mtO }
En_8H[<% }
Kg67cmj)f if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
dju{&wo~4 for(int index=0;index<MAX_KEY;index++){
TI&J>/z;$ if(hCallWnd[index]==NULL)
e%>E| 9*u continue;
rt;>pQ9, if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
(ajX;/ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
/bk} J:QRg //lParam的意义可看MSDN中WM_KEYDOWN部分
&!MKqJ@t }
39eoL;O_ }
M$A! }
`Yve
return CallNextHookEx( hHook, nCode, wParam, lParam );
4D$E }
P=z':4,M} Y" |U$ 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:
[_Z3v,vt, <[~M|OL9q, BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
IrM3Uh BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
gI{F"7fa= `-2`UGB- 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:
QKQy)g akwVU\RP LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
PxY"{-iAM {
z [{%.kA if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
H#akE\, {
!4fL|0 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
M-t9zT SaveBmp();
D1a2|^zt
return FALSE;
Y?x3JU0_ }
7T78S&g …… //其它处理及默认处理
^ 2tCDm5 }
`R;XN- ;[ojwcK[ZF !;oBvE7Kh 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。
7 c7SU^hD ?y
kIi/ 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。
::w%rv kY&j~R[C 二、编程步骤
:l{-UkbB 5j%jhby? 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";
E2cmT$6 LdV_7) 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
<jjaqDSmz K;O\Pd 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
y6\#{
qr1^i1%\ 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
BZsxf'eN' aqgSr| 5、 添加代码,编译运行程序。
[;+YO) EY(4<;) 三、程序代码
NKN!X/P {fs(+
0ei ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
eP8wTStC #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
jkd8M;Jw #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
N0NMRU]zT #if _MSC_VER > 1000
uv4jbg}Z+3 #pragma once
/);6 j,x #endif // _MSC_VER > 1000
x8t1g,QA #ifndef __AFXWIN_H__
1l{n`gR #error include 'stdafx.h' before including this file for PCH
z841g `:C #endif
DzMk eX #include "resource.h" // main symbols
Zf! 7pM class CHookApp : public CWinApp
nLQJ~(" {
.7q#{`K^= public:
QaV*}W CHookApp();
~V4|DN[I // Overrides
mJ HX
// ClassWizard generated virtual function overrides
]b)(=-;> //{{AFX_VIRTUAL(CHookApp)
y!].l0e2a public:
oz--gA:g virtual BOOL InitInstance();
oUH\SW8? virtual int ExitInstance();
6$Y1[ //}}AFX_VIRTUAL
9dAsXEWh //{{AFX_MSG(CHookApp)
08Gr // NOTE - the ClassWizard will add and remove member functions here.
?Z"}RMM)8 // DO NOT EDIT what you see in these blocks of generated code !
]T1"3
[si //}}AFX_MSG
GU9`;/ DECLARE_MESSAGE_MAP()
2q>4nN };
0nX5
$Kn LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
%"tf`,d~3 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
gxiJ`.D= BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
2]l*{l^ Bl BOOL InitHotkey();
v%r! }s BOOL UnInit();
f/xBR"' #endif
IdM;N >ObpOFb% //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
S<44{
oH #include "stdafx.h"
x<" e #include "hook.h"
gNJ\*]SY #include <windowsx.h>
$kdfY'u #ifdef _DEBUG
+!rK4[W' #define new DEBUG_NEW
Nz8iU@!a #undef THIS_FILE
Pj$a$C`Z static char THIS_FILE[] = __FILE__;
=0A{z#6 #endif
s<{c?4T #define MAX_KEY 100
"D+QT+sD #define CTRLBIT 0x04
=e63>*M| #define ALTBIT 0x02
CwAl-o #define SHIFTBIT 0x01
H]-nm+ #pragma data_seg("shareddata")
_oWenF HHOOK hHook =NULL;
Jx_4:G UINT nHookCount =0;
@<P[z[ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
$JOIK9+3z# static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
@-wAR=k7 static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
cI H`,bR static int KeyCount =0;
MFVFr " static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
!Lo{zTDW #pragma data_seg()
jhHb[je~{4 HINSTANCE hins;
*GA#.$n void VerifyWindow();
~0`Pe{^* BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
Z`[j;=[ //{{AFX_MSG_MAP(CHookApp)
0kDT:3 // NOTE - the ClassWizard will add and remove mapping macros here.
S5;q)qz2J // DO NOT EDIT what you see in these blocks of generated code!
3|C"F-'< //}}AFX_MSG_MAP
t]V)3Ww END_MESSAGE_MAP()
B$HQFdTli Qx:+n`$/ CHookApp::CHookApp()
XHW{EVcF {
W[b/.u5z: // TODO: add construction code here,
2-
)Ml* // Place all significant initialization in InitInstance
wvfCj6}S& }
N24+P5 |Q$C%7 CHookApp theApp;
)]>9\( LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
gpPktp2 {
hPl;2r BOOL bProcessed=FALSE;
/c09-$M if(HC_ACTION==nCode)
?C_%"!GR {
YO=;)RA if((lParam&0xc0000000)==0xc0000000){// Key up
SU*P@?:/} switch(wParam)
nC z[#t {
]M_)f case VK_MENU:
4;_.|!LN MaskBits&=~ALTBIT;
Q)v8hNyUmA break;
8ciLzyrY* case VK_CONTROL:
+ISB"a MaskBits&=~CTRLBIT;
Re=bJ|wo break;
8s|r' case VK_SHIFT:
a-7nA MaskBits&=~SHIFTBIT;
Dq\#:NnKvx break;
WvR}c default: //judge the key and send message
P0W%30Dh break;
X(bb1 }
%o~zsIl for(int index=0;index<MAX_KEY;index++){
0DN:{dJz if(hCallWnd[index]==NULL)
1r@v
\#P continue;
!
$n^Ze2 ! if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
h~dM*yo; {
-WEiY SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
GSl\n"S]= bProcessed=TRUE;
U5Rzfm4 }
^ K/B[8 }
`W"-jz5#= }
UF}fmDi else if((lParam&0xc000ffff)==1){ //Key down
WS;3a}u switch(wParam)
8z@A/$T {
5e/%Tue. case VK_MENU:
j J9| MaskBits|=ALTBIT;
EQg
6*V break;
o#;w>- case VK_CONTROL:
/+'@}u
| MaskBits|=CTRLBIT;
-5.>9+W8I break;
w+}KX><r case VK_SHIFT:
_,vJ0{* MaskBits|=SHIFTBIT;
5"{wnnY%K} break;
9)wjVk default: //judge the key and send message
rBpr1XKl, break;
)Y)7p// }
wd u>3Ch"y for(int index=0;index<MAX_KEY;index++)
SJw0y[IL6( {
|]Ockg[ if(hCallWnd[index]==NULL)
vhT9#) HI continue;
L[IjzxUv if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
m"u 9AOH k {
_w)0r}{ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
K?P.1H` bProcessed=TRUE;
(RGl, x: }
|
YvO$4=s }
Yh"R# }
UUX
_x?BD if(!bProcessed){
s*rtm for(int index=0;index<MAX_KEY;index++){
DT_012z if(hCallWnd[index]==NULL)
x!S8' continue;
OS,-dG( if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
9n$$D; SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
I4u'b?*
je }
3<B{-z }
yl|+D] }
2f F)I& return CallNextHookEx( hHook, nCode, wParam, lParam );
)-[X^l
j }
*,mbZE=< u{8Wu; BOOL InitHotkey()
b@nbXm]Z {
S&@~F| if(hHook!=NULL){
;b(/PH!O nHookCount++;
~ 5`Ngpp return TRUE;
g~N)~]0{ }
}k'8*v}8 else
>C@fSmnOM hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
QiY7m<3 if(hHook!=NULL)
fyT! / nHookCount++;
$yRbo'- return (hHook!=NULL);
;9d(GP}eE }
f'*HP%+Y BOOL UnInit()
Q TM+WD {
?DM-C5$ if(nHookCount>1){
8&H1w9NrX_ nHookCount--;
Wu%;{y~#} return TRUE;
hnL(~ }
CEt_wKzf BOOL unhooked = UnhookWindowsHookEx(hHook);
CfA
F.H if(unhooked==TRUE){
3)I v8mA nHookCount=0;
WF_G GF{ hHook=NULL;
m&b!\"0 }
HA"LU;5>2J return unhooked;
ai#0ZgO }
.GLotc v='7.A BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
QR<IHE{~8 {
[BmondOx BOOL bAdded=FALSE;
0p:n'P for(int index=0;index<MAX_KEY;index++){
X=_N7! if(hCallWnd[index]==0){
qDOx5.d hCallWnd[index]=hWnd;
^hTq~ " HotKey[index]=cKey;
D6c4tA^EO HotKeyMask[index]=cMask;
dLG5yx\js bAdded=TRUE;
%]RzC`NZ KeyCount++;
F71.%p7C8" break;
TC"mP!1 }
?5"~V^L3 }
F6YMcdU return bAdded;
sm/l'e }
;%hlh)k$ : E]A51 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
m3K8hL/ {
n+j'FfSz BOOL bRemoved=FALSE;
7J7uHl`yq` for(int index=0;index<MAX_KEY;index++){
Q{V|{yV^y if(hCallWnd[index]==hWnd){
T<?JL.8 g_ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
(N0G[(> hCallWnd[index]=NULL;
*}A J7] HotKey[index]=0;
|_
E)2b:h HotKeyMask[index]=0;
y~Sh|2x8v bRemoved=TRUE;
.,<-lMC+ KeyCount--;
;g7nG{ break;
1/JgirVA }
-.i1l/FzP }
^~8l|d_ }
#Z(8 vA^@ return bRemoved;
8iR%?5 >K }
w~X1Il7A sf@g $ void VerifyWindow()
@y{Whun~ {
ZOyq{w!2 for(int i=0;i<MAX_KEY;i++){
"{AS5jw if(hCallWnd
!=NULL){ &3'II:x(
if(!IsWindow(hCallWnd)){ B7_:,R.l
hCallWnd=NULL; teQ%t~PJ-&
HotKey=0; mS0*%[S {
HotKeyMask=0; kce+aiv|u
KeyCount--; Dm"GCV
} E;9SsA
} 7YkxIzE
} n<y!@p^X
} I(
G8cK
\{P(s:
BOOL CHookApp::InitInstance() X#Ajt/XQ
{ 7Oru{BQ">
AFX_MANAGE_STATE(AfxGetStaticModuleState()); }`\+_@w
hins=AfxGetInstanceHandle(); gNo.&G [
InitHotkey(); ~;3N'o
return CWinApp::InitInstance(); LezM=om.
} BoHMz/DB
aKhI|%5kA
int CHookApp::ExitInstance() WdnCRFO?l
{ %7z
VerifyWindow(); jun>(7
UnInit(); .COY%fz
return CWinApp::ExitInstance(); 7.hn@_
} zgJ%Zr!~
ccZ A
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file t%/Y^N;
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) G<Z|NT
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ `$fwLC3j
#if _MSC_VER > 1000 <