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:
)qyJwN
.D
.mr&zq 一、实现方法
nTG @=C# 2 %`~DVo 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:
q:}Q5gzZ DQ#rZi3I #pragma data_seg("shareddata")
H<Ne\zAv HHOOK hHook =NULL; //钩子句柄
q?&Ap* UINT nHookCount =0; //挂接的程序数目
&oU) ,H static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
B^;G3+} static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
"L?h@8sa static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
o7_*#5rD static int KeyCount =0;
@ )bCh(u static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
D90.z"N\i9 #pragma data_seg()
{c(@u6l28 BVJ6U[h` 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。
( o(, ; zCpsGr 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:
,sa%u Fm -[h2fqu1 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
YI877T9> cKey,UCHAR cMask)
HITw{RPrW {
BXzn-S BOOL bAdded=FALSE;
9 a$\l2 for(int index=0;index<MAX_KEY;index++){
Qru
iQ/t if(hCallWnd[index]==0){
%>)HAx ` hCallWnd[index]=hWnd;
CXAW>VdK_ HotKey[index]=cKey;
uPbGQ :%} HotKeyMask[index]=cMask;
ls;!Og9 bAdded=TRUE;
5]c\{G KeyCount++;
80'!XKSP break;
b6]MJ0do }
3dl#:Si }
?3duW$` return bAdded;
k}0Y&cT!rU }
3QD+&9{D //删除热键
qcmf*Yl:v BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
[.
rULQl {
6d# 7 BOOL bRemoved=FALSE;
2#i*'. for(int index=0;index<MAX_KEY;index++){
j\LJ{?;jC if(hCallWnd[index]==hWnd){
B(eC|:w[z if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
*wfb~&:} hCallWnd[index]=NULL;
Y<ZaW{% HotKey[index]=0;
g"KH~bN HotKeyMask[index]=0;
I:l/U-b7h bRemoved=TRUE;
C6PlO KeyCount--;
B$\,l.hE break;
6r]l8*34; }
o/J2BZ<_< }
K6z)&< }
h1_9Xp~N return bRemoved;
8kRqF?rbj }
{:%A
"p"M9P' j%q,]HCANh DLL中的钩子函数如下:
u)hr f[XsnN2 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
eI^Q!b8n {
.Fl5b}C( BOOL bProcessed=FALSE;
%v"qFYVX" if(HC_ACTION==nCode)
Dt ~3Qd0 {
rGqT[~{t if((lParam&0xc0000000)==0xc0000000){// 有键松开
]di^H>,xU switch(wParam)
~d9@m#_T#~ {
j,Vir"-) case VK_MENU:
Fr|Ts>Kx MaskBits&=~ALTBIT;
=>0G break;
(fTi1
I! case VK_CONTROL:
)q8!:Z MaskBits&=~CTRLBIT;
N E/ _ break;
,zP.ch0K case VK_SHIFT:
{0~xv@ U MaskBits&=~SHIFTBIT;
m"|AD/2;( break;
o3ZqPk]al default: //judge the key and send message
e.>>al break;
B/^1uPTZ71 }
wBJP8wES= for(int index=0;index<MAX_KEY;index++){
c]x'}Kc if(hCallWnd[index]==NULL)
L7rEMq continue;
CKuf'h# if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
37U2Tb!y' {
LP{@r ic SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
.wPu
#* bProcessed=TRUE;
k@Q>(` }
%"gV>E_u }
C4h4W3w }
aj|gt else if((lParam&0xc000ffff)==1){ //有键按下
*?`<Ea switch(wParam)
Ij_h #f {
V|q`KOF case VK_MENU:
0;X0<IV MaskBits|=ALTBIT;
?3t]9z break;
5;:964Et case VK_CONTROL:
G,-x+e" MaskBits|=CTRLBIT;
66Tx>c"H break;
cg|C S? case VK_SHIFT:
qN@-H6D1= MaskBits|=SHIFTBIT;
_yu_Ev}R break;
Mv 1V
Vk default: //judge the key and send message
ln*_mM/Q% break;
'7ps_pz }
M!#[(: for(int index=0;index<MAX_KEY;index++){
lDf:~ if(hCallWnd[index]==NULL)
IV]2#;OO? continue;
%I^y@2A4` if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Y )](jU%o {
0XLoGQ= SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
FJC}xEMcN bProcessed=TRUE;
?,AWXiif }
SQhw |QdG }
WvVf+|Km }
IPxK$nI^ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
\*r]v;NcP for(int index=0;index<MAX_KEY;index++){
Y5XhV;16 if(hCallWnd[index]==NULL)
'"4S3Fysm continue;
^1jZwP;5eW if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
[+_0y[~,tB SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
8EC$p} S //lParam的意义可看MSDN中WM_KEYDOWN部分
O@)D%*;v }
&"/IV$H }
0'nY }
Ed ,O>( return CallNextHookEx( hHook, nCode, wParam, lParam );
.G/2CVMj }
,nnVHBN =L F9im 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:
+}-Ecr ,2/y(JX}*! BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
_rIFwT1] BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
\|< 5zL #$*l#j"#A 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:
j%TcW!D-_ QBwgI>zfS" LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
Ip&Q'"HYj {
lr-:o@q{ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
/2jw]ekQ' {
d2=Z=udd //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
.`5BgX7W SaveBmp();
4.o[:5' return FALSE;
z&W5@6")` }
o0`|r+E\ …… //其它处理及默认处理
k,M%"FLQ }
|j>fsk~ f !D~aJ 'du{ky 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。
U%zZw) oHvVZ 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。
$9In\x
cpe/GvD5] 二、编程步骤
%$3)xtS6 `GQ'yv 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";
Qf<@
:T* r-]Hm Y x 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
A3cW8OClz ^cz;UQX~} 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;
gsD0N^ aa10vV 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;
^N2N>^'&1. .V'=z| 5、 添加代码,编译运行程序。
~V?3A/] #fTPo:*t 三、程序代码
+i1\],7 _=d
X01 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
S-D=-{@ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
)?D w)s5 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
_WeN\F~^ #if _MSC_VER > 1000
cPL]WI0( #pragma once
qL1d-nH #endif // _MSC_VER > 1000
dXvp-oi #ifndef __AFXWIN_H__
kIlK"= #error include 'stdafx.h' before including this file for PCH
;+W9EbY2 #endif
:Tu%0="ye #include "resource.h" // main symbols
:4'Fq;%C class CHookApp : public CWinApp
D/7hVwMw: {
JAA{5@ST public:
1p]Z9$Y CHookApp();
IP
e"9xb // Overrides
wg0hm#X // ClassWizard generated virtual function overrides
Dw-i!dq //{{AFX_VIRTUAL(CHookApp)
kV$$GLD\ public:
Ohe*m[ virtual BOOL InitInstance();
WG\gf\= I virtual int ExitInstance();
V {H/>>k7 //}}AFX_VIRTUAL
PRi3=3oF //{{AFX_MSG(CHookApp)
H6Qb]H.C // NOTE - the ClassWizard will add and remove member functions here.
]Y%U5\$ // DO NOT EDIT what you see in these blocks of generated code !
ujMics( //}}AFX_MSG
UC{Tm f DECLARE_MESSAGE_MAP()
M!nwcxB! };
leMcY6 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
-g`3;1EV^ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
Z-wvdw]$ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
}?vVJm' BOOL InitHotkey();
0*-nVC1 BOOL UnInit();
RxZ#`$F #endif
))z1T 8 48 | u{ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
n;+e( ob;; #include "stdafx.h"
XnCrxj #include "hook.h"
Js("H #include <windowsx.h>
;?`l1:C5) #ifdef _DEBUG
3$hbb6N%6. #define new DEBUG_NEW
k=o>DaEh( #undef THIS_FILE
SFdSA4D" static char THIS_FILE[] = __FILE__;
fL7u419= #endif
}G50?"^u #define MAX_KEY 100
(K>=!&tlp= #define CTRLBIT 0x04
.xIu #define ALTBIT 0x02
vs|_l!n3 #define SHIFTBIT 0x01
N)rf/E0 #pragma data_seg("shareddata")
IC:wof " HHOOK hHook =NULL;
$F,&7{^ UINT nHookCount =0;
mhXSbo9w- static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
ygz6 ~( static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
Q#$#VT!F static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
qp6*v& static int KeyCount =0;
*gxo!F} static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
pPX ~pPIj2 #pragma data_seg()
=e>#oPH HINSTANCE hins;
XA%a7Xtni void VerifyWindow();
iH#b"h{w BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
14,Pf`5Sz //{{AFX_MSG_MAP(CHookApp)
9^5D28y // NOTE - the ClassWizard will add and remove mapping macros here.
aTx*6;-PH // DO NOT EDIT what you see in these blocks of generated code!
3>I //}}AFX_MSG_MAP
_\y%u_W END_MESSAGE_MAP()
:y!%GJW hk+8s\%- CHookApp::CHookApp()
e dTFk$0 {
a\-AGG{2/X // TODO: add construction code here,
:A7\eN5 // Place all significant initialization in InitInstance
dJv2tVm&' }
?}RPnf +>3jMs~& CHookApp theApp;
[s4|+ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
tn{YIp {
:a/l9 m( BOOL bProcessed=FALSE;
ONVhB if(HC_ACTION==nCode)
y%Rq6P=4Q {
Ie4\d2tQ; if((lParam&0xc0000000)==0xc0000000){// Key up
wKU9I[] switch(wParam)
igx~6G* {
C19}Y4r: case VK_MENU:
mUj_V#v MaskBits&=~ALTBIT;
PctXh, = break;
"7q!u,u case VK_CONTROL:
P{,A% t MaskBits&=~CTRLBIT;
ui
RO,B}z break;
.(RZ&*4 case VK_SHIFT:
iC{(vL0P+ MaskBits&=~SHIFTBIT;
]ur?i{S, break;
{p.^E5& default: //judge the key and send message
&@K6;T break;
b)eoFc)lc }
1etT." for(int index=0;index<MAX_KEY;index++){
%oB0@&!mS if(hCallWnd[index]==NULL)
ZIN1y;dJ continue;
,eGguNA9 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
GKc? {
<?nz>vz SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
u*f`\vs bProcessed=TRUE;
/WGD7\G'8 }
|LW5dtQ }
[tT_ z<e` }
yh2)Pc[ else if((lParam&0xc000ffff)==1){ //Key down
S B~opN switch(wParam)
-Uan.#~S {
!2kM case VK_MENU:
Mw3$QRM MaskBits|=ALTBIT;
fMIRr5 break;
k%3)J"|/ case VK_CONTROL:
IL g o:xQ MaskBits|=CTRLBIT;
#{*5rKiL break;
5,-g^o7 case VK_SHIFT:
)DmydyQ' MaskBits|=SHIFTBIT;
CBO*2?]s break;
",l6-<s default: //judge the key and send message
!Q WNHL break;
7t+d+sQ-l }
mPU}]1*p for(int index=0;index<MAX_KEY;index++)
svx7 {
AR!v%Z49i if(hCallWnd[index]==NULL)
NE.h/+4 continue;
v%$l( if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
ht*N[Pi4; {
,m[XeI SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
&?@[bD'T bProcessed=TRUE;
#|K{txC
}
tm/=Oc1p }
X::@2{-@y }
\=D+7'3 if(!bProcessed){
+oh |r'~ for(int index=0;index<MAX_KEY;index++){
Nyt*mbd5
{ if(hCallWnd[index]==NULL)
Zb=;\l*& continue;
MJh.)kd$ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
>fMzUTJ4 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
wo+`WnDh }
tA^+RO4 }
X{Fr }
o{>4PZ}=g return CallNextHookEx( hHook, nCode, wParam, lParam );
X1d{7H8A2 }
5kGQf w[F})u]E BOOL InitHotkey()
8nng^ {
=/}Rnl+c if(hHook!=NULL){
e]nP7TIU nHookCount++;
oKYa? return TRUE;
8o[gzW:Q)U }
"n]x%. * else
>;XtJJS hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
[
:)F- if(hHook!=NULL)
CuK>1_Dq nHookCount++;
T_!F I29 return (hHook!=NULL);
cHt4L]n8n }
Oe
x
BOOL UnInit()
]h~F%
{
i9Beap/t$ if(nHookCount>1){
0J^Z)U>j nHookCount--;
w+"E{#N return TRUE;
*Lxt{z`9 }
c0Bqm BOOL unhooked = UnhookWindowsHookEx(hHook);
wm^1Fn-- if(unhooked==TRUE){
}-sh nHookCount=0;
SHs [te[ hHook=NULL;
Lc?"4 }
g%tUk M return unhooked;
1TX3/]: }
tH&eKM4G tvf5b8(Y- BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
K\KQ(N8F {
C[<{>fl) BOOL bAdded=FALSE;
oQrfrA&=M for(int index=0;index<MAX_KEY;index++){
]]_5_)"4 if(hCallWnd[index]==0){
ZnJJ-zP hCallWnd[index]=hWnd;
NC!B-3?x HotKey[index]=cKey;
y9?*H?f, HotKeyMask[index]=cMask;
Iila|,cM bAdded=TRUE;
GApvRR+Z KeyCount++;
pY-!NoES break;
~Er0$+q=Y; }
IP$eJL[&D" }
5L<A7^j return bAdded;
Xp|4 WM }
ob8}v*s r>! @Z2%s BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
9(qoME}>= {
q+4dHS)x BOOL bRemoved=FALSE;
5x|$q kI for(int index=0;index<MAX_KEY;index++){
x0>N{ADXQ if(hCallWnd[index]==hWnd){
X.>~DT%0Lm if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
`),U+ hCallWnd[index]=NULL;
5FuV=Y uc HotKey[index]=0;
A(uo%QE| HotKeyMask[index]=0;
B_iaty bRemoved=TRUE;
={v(me0ZPb KeyCount--;
U\ ,N break;
:R
+BC2x }
FWU>WHX }
-(e=S^36 }
^wc:qll return bRemoved;
@=Pc{xp }
v FQ]>nX .SmG) 5U] void VerifyWindow()
88<d<)7t {
yPT o,,ca= for(int i=0;i<MAX_KEY;i++){
5D=U.UdR if(hCallWnd
!=NULL){ ]@cI _n
if(!IsWindow(hCallWnd)){ F'>yBDm*OM
hCallWnd=NULL; %).I&)i
HotKey=0; AX&Emz-
HotKeyMask=0; GIkeZV{4}
KeyCount--; Ct?xTFb
} uPbdzUk$
} wSCI?
} O"|d~VQ
} .b`8
+
7p\&