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:
0(VQwGC[
*B(na+ 一、实现方法
Zg%SE'kK IEV3(qzt 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:
X%!#Ic]Q kWL\JDZ`. #pragma data_seg("shareddata")
=V:rO;qX+@ HHOOK hHook =NULL; //钩子句柄
.Ev i UINT nHookCount =0; //挂接的程序数目
(6p5Fo static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
j r6)K;:. static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
uQ#3;sFO static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
!8]W"@qb static int KeyCount =0;
xz YvD{> static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
JpDc3^B* #pragma data_seg()
zH8l-0I+$ JZ&]"12]fR 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。
V ^=o@I fL4F
~@`9l 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:
=8 d`qS" "(ehf|%>% BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
}' `2C$ cKey,UCHAR cMask)
5:SfPAx {
w}pFa76rm BOOL bAdded=FALSE;
@)iv' for(int index=0;index<MAX_KEY;index++){
P-ma~g>I if(hCallWnd[index]==0){
:NHh`@0F hCallWnd[index]=hWnd;
$H ^hK0?' HotKey[index]=cKey;
m*h
d%1D HotKeyMask[index]=cMask;
& v=2u,]T bAdded=TRUE;
|r5|IA KeyCount++;
Vin d\yvM break;
G8"L#[~ }
|{HtY }
pdsjX)O+f return bAdded;
~DcX}VCm }
]>K%,}PS //删除热键
7,ODh-?ez BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
,dKcxp~[ {
}Tn]cL{]C BOOL bRemoved=FALSE;
R%XbO~{u for(int index=0;index<MAX_KEY;index++){
uY5 &93R if(hCallWnd[index]==hWnd){
FLY# if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
/kyuL]6 hCallWnd[index]=NULL;
*iS<]y HotKey[index]=0;
G}mJtXT#= HotKeyMask[index]=0;
N. 3
x[%: bRemoved=TRUE;
z (r Q6 KeyCount--;
nm66U4.@ break;
}NDw3{zn }
J\XYUs }
)DuOo83n[" }
ws4a(1 return bRemoved;
mKynp }
\(jSkrrD IZeWswz GEy^*, d DLL中的钩子函数如下:
9>d$a2nc :<Y,^V( LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
T<~NB5&f {
#)_4$<P*' BOOL bProcessed=FALSE;
o6K\z+.{ if(HC_ACTION==nCode)
HgE^#qD? {
LJYFz=p" if((lParam&0xc0000000)==0xc0000000){// 有键松开
K~AQ) ]pJI switch(wParam)
CD%wi:C%| {
+LV~%?W case VK_MENU:
ZeF PwW MaskBits&=~ALTBIT;
draY/ break;
mYXe0E#6 case VK_CONTROL:
|#$Wh+,* MaskBits&=~CTRLBIT;
FVsVY1 break;
D_D<N(O case VK_SHIFT:
X'e@(I!0 MaskBits&=~SHIFTBIT;
1Ah break;
&H;0N"Fn default: //judge the key and send message
G $:T! break;
bl(rCbj(w }
V[Fzh\2n for(int index=0;index<MAX_KEY;index++){
Xm*gH, ' if(hCallWnd[index]==NULL)
4&~1|B{Z continue;
Zz=+?L if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
v! uD]} {
Hb=4k)-/] SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
cD
Z]r@AQ bProcessed=TRUE;
[F%INl-sy }
n
!]_o }
X*1vIs;[@ }
G%-[vk#] else if((lParam&0xc000ffff)==1){ //有键按下
Ki{&,:@ switch(wParam)
Uaog_@2n, {
5Y)*-JY1g case VK_MENU:
B.6gJ2c MaskBits|=ALTBIT;
2ksX6M3kY break;
mu04TPj case VK_CONTROL:
]wWN~G)2lV MaskBits|=CTRLBIT;
U)=?3}s( break;
*xA&t)z(i case VK_SHIFT:
8-UlbO6 MaskBits|=SHIFTBIT;
_a"5[sG break;
:84fd\It4 default: //judge the key and send message
f"q='B9_T\ break;
?@6N EfQf }
y[oc^Zuo for(int index=0;index<MAX_KEY;index++){
q>X#Aaib if(hCallWnd[index]==NULL)
]6Kx0mW continue;
+rfw)c' if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
a,x-akZWf {
F]@vmzr SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
:w:hqe|_ bProcessed=TRUE;
w4<1*u@${ }
j8WnXp_ }
\I1+J9Gl }
ZGf R:a)wc if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
3|8\,fO? for(int index=0;index<MAX_KEY;index++){
Z\D!'FX if(hCallWnd[index]==NULL)
oOUL<ihe? continue;
,1EyT> if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
u;H SX SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Eb{Zm<TP //lParam的意义可看MSDN中WM_KEYDOWN部分
CWdA8)n. }
%WiDz0o }
5Jh=${ }
9'faH return CallNextHookEx( hHook, nCode, wParam, lParam );
@v\Osp t= }
`WGT`A" thIuK V{CO 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
pca `nN! >VM@9Cph BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
"VR>nyG% BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
.z4
fJx sxinA8 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
r ) ;U zd <R582$( I LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
<SGO+1ztp {
O{SP4|0JV if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
c+,F)i^` {
'`&gSL.1a@ //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
nh"nSBRxk SaveBmp();
UUJbF$@; return FALSE;
Q^>"AhOiU }
/ CEn yE/ …… //其它处理及默认处理
X*hY?'Rp }
W5PNp%+KE /#lhRNX g|ewc'y 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
jI%v[]V #N9^C@ 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
k#X~+}N^ }5
^2g!M 二、编程步骤
gpDH_!K y:u7*%" 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
b5lZ| |W. k=!lPIx 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
s:ig;zb ~Gm<F .(+ 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
^=`7]E [p 1=:=zyEEo 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
l{ <+V) 7.mY@ 5、 添加代码,编译运行程序。
5IE3[a%X {2 l35K= 三、程序代码
{~q"Y]? `u6CuH5 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
MIma:N_c #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
'[(]62j #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
'0q.zzv|_ #if _MSC_VER > 1000
uqy&PS #pragma once
3kfrOf.4h #endif // _MSC_VER > 1000
NV\t%/ ? #ifndef __AFXWIN_H__
N$]B$vv #error include 'stdafx.h' before including this file for PCH
ehCGu(= #endif
)N$T& #include "resource.h" // main symbols
xe?!UCUb@ class CHookApp : public CWinApp
VF[$hs {
G#yv$LY# public:
!jlLF:v|1A CHookApp();
"i>?Tg^ // Overrides
l@:Tw.+/9 // ClassWizard generated virtual function overrides
E$l 4v>iA //{{AFX_VIRTUAL(CHookApp)
-wn,7; public:
^f6pw! virtual BOOL InitInstance();
ov;1=M~RF virtual int ExitInstance();
"?9rJx$ //}}AFX_VIRTUAL
;B*im
S10 //{{AFX_MSG(CHookApp)
`%S 35x9 // NOTE - the ClassWizard will add and remove member functions here.
-wr#.8rzTT // DO NOT EDIT what you see in these blocks of generated code !
"3 Y(uN //}}AFX_MSG
)&/ecx"2Q DECLARE_MESSAGE_MAP()
oP>+2.i };
$fifx>! LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
-YvnX0j+ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
!UHWCJ<
<w BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
x -;tV=E} BOOL InitHotkey();
FK;3atrz BOOL UnInit();
,GOH8h #endif
EPeKg{w |ppG*ee //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
"06t"u<% #include "stdafx.h"
I;xSd.- #include "hook.h"
j-]`;&L #include <windowsx.h>
7pPaHX8 #ifdef _DEBUG
h;TN$ / #define new DEBUG_NEW
9-:\ NH^; #undef THIS_FILE
[vv $"$z static char THIS_FILE[] = __FILE__;
7:/gO~gI #endif
<|-da&7 #define MAX_KEY 100
T)c<tIr6 #define CTRLBIT 0x04
,J;Cb} #define ALTBIT 0x02
tzIcR
#Z #define SHIFTBIT 0x01
CghlyT #pragma data_seg("shareddata")
w?#s)z4}g HHOOK hHook =NULL;
Cb}I-GtO UINT nHookCount =0;
ehTrjb3k static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
zSd!n static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
Ww=^P{q\ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
w'uB&z4' static int KeyCount =0;
6W\G i> static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
LX'z7fh #pragma data_seg()
{,NF'x4$ HINSTANCE hins;
[?>\] void VerifyWindow();
&&PXWR!%] BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
-v %n@8p //{{AFX_MSG_MAP(CHookApp)
px${
"K< // NOTE - the ClassWizard will add and remove mapping macros here.
.9NYa |+0 // DO NOT EDIT what you see in these blocks of generated code!
"ov270: //}}AFX_MSG_MAP
iW%~>`tT END_MESSAGE_MAP()
i(qZ#oN NHaY&\ CHookApp::CHookApp()
G)8v~=Bv {
'3|fv{I // TODO: add construction code here,
=;Q:z^S // Place all significant initialization in InitInstance
h0.2^vM)R }
q-hR EO \s?8}k CHookApp theApp;
U9"(jl/o LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
9Bao~(j/k {
!S~0T!afF BOOL bProcessed=FALSE;
WQ+ xS!ba if(HC_ACTION==nCode)
CK+t6Gp {
{8* d{0l if((lParam&0xc0000000)==0xc0000000){// Key up
3\}>nE switch(wParam)
}]i.z:7+ {
FG!2h&k case VK_MENU:
|:w)$i& * MaskBits&=~ALTBIT;
I>EEUQR/$H break;
^UCH+Cyl case VK_CONTROL:
oGRd ;hsF MaskBits&=~CTRLBIT;
6gs0Vm break;
S4U}u l case VK_SHIFT:
[H[L};%=j MaskBits&=~SHIFTBIT;
KAJR.YNm break;
R53^3"q~ default: //judge the key and send message
Xp+lpVcJ break;
1/f{1k }
lqTc6@:D for(int index=0;index<MAX_KEY;index++){
r2*8.j51 if(hCallWnd[index]==NULL)
NkV81? continue;
A?bqDy if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
uH&B=w {
iE?yvtr8 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
b>2{F6F bProcessed=TRUE;
UgLFU# }
A.vf)hO }
PI.Zd1r }
Z;<:=# else if((lParam&0xc000ffff)==1){ //Key down
KKq%'y)u^ switch(wParam)
$cWt^B' {
ck< `kJ`b case VK_MENU:
-7KoR}Ck! MaskBits|=ALTBIT;
.?vHoNvo break;
8y']kVg case VK_CONTROL:
9}wI@ MaskBits|=CTRLBIT;
43 vF(<r&f break;
..kFn!5(g case VK_SHIFT:
]Cs=EZr MaskBits|=SHIFTBIT;
WG&! VK break;
fG d1 default: //judge the key and send message
ppo0DC\> break;
)@ofczl6 }
jddhX]>I for(int index=0;index<MAX_KEY;index++)
q3vv^~ {
_NB*+HVo if(hCallWnd[index]==NULL)
"F =NDF continue;
-{}h6r if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
*c\XQy {
boI&q>-6Re SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
's.e"F# bProcessed=TRUE;
NB4Q,iq$ }
Y&1N*@YP }
3G[|4v?[<_ }
"=w:LRw if(!bProcessed){
'QQq0. for(int index=0;index<MAX_KEY;index++){
xG;;ykh.] if(hCallWnd[index]==NULL)
q_6fr$-Qh continue;
H$ %F0'0 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
&09&;KJ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
GM8Q#vc }
wH$qj'G4CN }
`Se2f0", }
@ta:9wZ return CallNextHookEx( hHook, nCode, wParam, lParam );
-u(,*9]cJ* }
E~#G_opQA c4u/tt.) BOOL InitHotkey()
0hhxTOp
{
Rc:}%a%e if(hHook!=NULL){
>|z:CX$] nHookCount++;
tz8fZ*n return TRUE;
8k3y"239t }
Wsgp#W+ else
qw$9i.Z hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
<S=(`D if(hHook!=NULL)
MhR` nHookCount++;
RcO"k3J return (hHook!=NULL);
tfe]=_U }
0%Le*C'yk BOOL UnInit()
c~4Cpy^ {
ZY8w1:'
if(nHookCount>1){
tkH]_cH'w nHookCount--;
g^Hf^%3xP return TRUE;
UWnF2,<s; }
o">~ObR BOOL unhooked = UnhookWindowsHookEx(hHook);
M(nzJ if(unhooked==TRUE){
?HRS* nHookCount=0;
er5!ne hHook=NULL;
UOFb.FRP> }
_
xym return unhooked;
n807?FORB }
IIih9I`IR uJCp BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
"AZ|u#0P {
!qp$Xtf+ BOOL bAdded=FALSE;
"0uM%*2 for(int index=0;index<MAX_KEY;index++){
.;Mb4"7= if(hCallWnd[index]==0){
tewp-MKA hCallWnd[index]=hWnd;
<$yA* HotKey[index]=cKey;
`u}_O(A1pA HotKeyMask[index]=cMask;
mZ2CGOR bAdded=TRUE;
p3Qls* KeyCount++;
U#cGd\b break;
'iF%mnJ }
f]#\&" }
u178vby;l return bAdded;
Ovc9x\N }
JH{/0x#+ "5L?RkFi\ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
>t.Lc. {
{?`7D:]`^ BOOL bRemoved=FALSE;
=y-yHRC7 for(int index=0;index<MAX_KEY;index++){
-N% V5 TN if(hCallWnd[index]==hWnd){
hcj]T? if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
6i-G{)=l hCallWnd[index]=NULL;
T 5Zh2Q@ HotKey[index]=0;
+Eh.PWEe HotKeyMask[index]=0;
bS;_xDXd bRemoved=TRUE;
McN[ KeyCount--;
r}&&e BY
f break;
FJDC^@ Ne }
J{^md0l }
Mib.,J~ }
eM_;rM Cr} return bRemoved;
[:.wCG5 }
|,p"<a!+{w W M` 3QJb void VerifyWindow()
COsmVQ. {
d_d&su
E for(int i=0;i<MAX_KEY;i++){
=TDKU if(hCallWnd
!=NULL){ }< H> 9iJ:
if(!IsWindow(hCallWnd)){ 'bJGQ[c
hCallWnd=NULL; Bkd$'7UT
HotKey=0; e)wi}\:q_
HotKeyMask=0; _$96y]Bpi
KeyCount--; ed`"xm
} \894Jqh
} #?Kw
y
} 0:
a2ER|J
} $*942. =Q
wYf\!]}'
BOOL CHookApp::InitInstance() . 2$J-<O
{ 5PO_qr=Hx
AFX_MANAGE_STATE(AfxGetStaticModuleState()); JyZuj>`
6
hins=AfxGetInstanceHandle(); tO{{ci$-T
InitHotkey(); !h4T3sO
return CWinApp::InitInstance(); :c~SH/qS
} TL2E|@k1]
@>Yd6C
int CHookApp::ExitInstance() R1X'}#mU
{ .*x:
VerifyWindow(); w[
v{)
UnInit(); 9^W7i]-Z
return CWinApp::ExitInstance(); S[exnZ*Y
}
-DdHl8
*sOb I(&
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file 3~T ~Bs
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) ekvs3a^
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ B^/MwD>%
#if _MSC_VER > 1000 EjLq&QR.
#pragma once $KYGQP
#endif // _MSC_VER > 1000 WVRIq'
>t3_]n1e
class CCaptureDlg : public CDialog VKl,m ;&