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:
cO^}A(Ma( W^Z#_{ 一、实现方法
kjOPsz*0 3IHA+Zz 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:
?84B0K2Ns ?)i`)mu' #pragma data_seg("shareddata")
+Oa+G.;)o4 HHOOK hHook =NULL; //钩子句柄
WEVV2BJ UINT nHookCount =0; //挂接的程序数目
>UDb:N[ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
6<N Q/*(/ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
6nP-IKL static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
)mvD2]fK static int KeyCount =0;
DgiMMmpE static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
* M,'F^E2 #pragma data_seg()
9]^ CDL Rd^X. 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。
cc_v 4d{x !3 j@gi2 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:
U9:w ^t[Pp "FfIq; BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
/UAcN1K!B cKey,UCHAR cMask)
Sx|)GTJJ|- {
#HF;yAc BOOL bAdded=FALSE;
[>y 0Xf9^ for(int index=0;index<MAX_KEY;index++){
\yNe5 if(hCallWnd[index]==0){
6}xFE]Df-Y hCallWnd[index]=hWnd;
c[RkiV3 HotKey[index]=cKey;
|r%lJmBB HotKeyMask[index]=cMask;
k),!%6\( bAdded=TRUE;
uBXl ltU KeyCount++;
O!=ae| break;
U6M3,"? }
z0Bw+&^]} }
]x<`( return bAdded;
T~"T%r }
c4AkH| //删除热键
K)!Nf.r$9 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
C%)Xz {
dD{{G:V BOOL bRemoved=FALSE;
1O{x9a5Z?O for(int index=0;index<MAX_KEY;index++){
5C&]YT3) if(hCallWnd[index]==hWnd){
`+>'18F if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Y o$NE hCallWnd[index]=NULL;
; M%n=+[O HotKey[index]=0;
1s@%q
< HotKeyMask[index]=0;
!f^'- bRemoved=TRUE;
O?I~XM'S KeyCount--;
XKEd~2h<y break;
FBCi,_
\4 }
4?s
~S. % }
paG^W&`; }
vUa&9Y return bRemoved;
8ezdU" }
9Nkr=/I"P A^9RGz4= yS)73s/MrY DLL中的钩子函数如下:
M],}.l -(Y( K!n LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
rnV\O L {
=ZaTD-%id BOOL bProcessed=FALSE;
,( ?q if(HC_ACTION==nCode)
t"]+}]O {
HpD<NVu if((lParam&0xc0000000)==0xc0000000){// 有键松开
tAM t7p- switch(wParam)
>#Obhs|S{C {
@D3Y}nR: case VK_MENU:
uIO<6p) MaskBits&=~ALTBIT;
('u\rc2R break;
!Xzne_V< case VK_CONTROL:
4%(\y"T MaskBits&=~CTRLBIT;
mEUdJvSG( break;
0F495'*A case VK_SHIFT:
jBO/1h= MaskBits&=~SHIFTBIT;
wM"PJG break;
wePhH*nQ> default: //judge the key and send message
L/U^1=Wi*O break;
el;ey Ga }
?C[W~m P for(int index=0;index<MAX_KEY;index++){
)Uk!;b if(hCallWnd[index]==NULL)
k[`9RGT continue;
M!9gOAQP if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
4w\@D>@}H {
K9*vWoP' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
[K\Vc9 bProcessed=TRUE;
{-T}"WHg7 }
7l%]/`Y- }
#'@pL0dj }
DhVF^=x$ else if((lParam&0xc000ffff)==1){ //有键按下
IYo{eX~= switch(wParam)
f[AN=M"B"s {
z;dFS case VK_MENU:
h
"MiD MaskBits|=ALTBIT;
[T(XwA) break;
Y M<8>d case VK_CONTROL:
/.{q2] MaskBits|=CTRLBIT;
V?.')?'V break;
907N;r case VK_SHIFT:
.}wVM`81z MaskBits|=SHIFTBIT;
"x+o(jOy break;
X4c|*U=4 default: //judge the key and send message
R-~ZvVw7L break;
8,0WHivg }
$y0[AB|V for(int index=0;index<MAX_KEY;index++){
*CIR$sS if(hCallWnd[index]==NULL)
_{]\} =@ continue;
zmw <y2` if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
bp>-{Nv {
kXfTNMb SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
X{ZcJ8K bProcessed=TRUE;
|8bqn^@$t }
[eb?Fd~WB] }
]f3[I3;K }
l8XgzaW if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
>{seaihK for(int index=0;index<MAX_KEY;index++){
[{i"Au] if(hCallWnd[index]==NULL)
Ap:mc: continue;
<Va7XX%> if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
K-a~Kr SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
X6hp} //lParam的意义可看MSDN中WM_KEYDOWN部分
_|'e Az }
vky@L! &, }
prWK U }
K4G43P5q` return CallNextHookEx( hHook, nCode, wParam, lParam );
<r@w`G }
^Uj\s / ($h`Y;4 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:
gXNlnh%?S wjVmK BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
RjcU0$Hi BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
17
k9h?s* K+s@.D9J 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
|g$n-t 3Uy4 8ue LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
Xxz_h* {
3tt3:`g if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
1?oX" {
)$>
pu{o //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
W0&x0 SaveBmp();
b-`=^ny)K return FALSE;
XK";-7TZt }
M MQ^&!H …… //其它处理及默认处理
Fx3CY W }
t1Zcr#b> _x2i=SFo*$ AgBXB%). 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。
1@i|[dq 6XFLWN-) 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。
&2P+9j> SyB2A\A 二、编程步骤
@{X<|,W9w MyJ\/` 8 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";
w
YEkWB^ mnG\qsKNLK 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
vOIzfwYG9 tQ@%3` 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;
gfW_S&&q ^5GyW`a}
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;
zUIh^hbFf R/O>^s!Co 5、 添加代码,编译运行程序。
YAc~,N UyUz_6J 三、程序代码
}Z,x F` m-v0=+~& ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
BKV,V/*p #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
nj(\+l5 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
auai@)v6 #if _MSC_VER > 1000
'|7'dlW #pragma once
,bGYixIfYZ #endif // _MSC_VER > 1000
6z'3e\x #ifndef __AFXWIN_H__
M}S1Zz%Ii1 #error include 'stdafx.h' before including this file for PCH
)ZQ>h{}D #endif
v]?zG&Jh #include "resource.h" // main symbols
XzD+#+By class CHookApp : public CWinApp
=>LQW;Sjz {
z*w.A=r public:
'O+)[D CHookApp();
}|j\QjH // Overrides
}ZKG-~ // ClassWizard generated virtual function overrides
L>>RboR} //{{AFX_VIRTUAL(CHookApp)
I"hlLP public:
J/(^Z?/~P! virtual BOOL InitInstance();
7/969h^s virtual int ExitInstance();
)s~szmJoVD //}}AFX_VIRTUAL
t8?$q})RL //{{AFX_MSG(CHookApp)
Pl\r|gS; // NOTE - the ClassWizard will add and remove member functions here.
579<[[6~d2 // DO NOT EDIT what you see in these blocks of generated code !
%ZR<z$ //}}AFX_MSG
b uu /Nz$ DECLARE_MESSAGE_MAP()
]=Dzr<*v };
;ipT0*Y LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
k
E},>+W+ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
lvd`_+P$ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
uz
/Wbc>y BOOL InitHotkey();
M?ObK#l!_ BOOL UnInit();
r?$V;Z #endif
G&z^AV bP)(4+t~ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Q`m9I #include "stdafx.h"
@j`gxM_-O #include "hook.h"
!Pc&Sg #include <windowsx.h>
&~KAZ}xu #ifdef _DEBUG
]k#iA9I #define new DEBUG_NEW
:lBw0{fP #undef THIS_FILE
$}8@?>-w static char THIS_FILE[] = __FILE__;
[aF"5G #endif
k~XDwmt; #define MAX_KEY 100
;W?mQUo:P8 #define CTRLBIT 0x04
bamQ]>0|>! #define ALTBIT 0x02
I&wJK'GM` #define SHIFTBIT 0x01
,.z?=]'en #pragma data_seg("shareddata")
TFG0~"4Cz HHOOK hHook =NULL;
&hcD/*_Z UINT nHookCount =0;
;wa#m1 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
dJF3]h Y static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
GCj[ySCD static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
w'6sJ#ba( static int KeyCount =0;
*_sSM+S static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
d<cqY<y VA #pragma data_seg()
u\q(v D. HINSTANCE hins;
O<P(UT" void VerifyWindow();
<)a7Nrc\T BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
q|sT4}
= //{{AFX_MSG_MAP(CHookApp)
]NyN@9u@( // NOTE - the ClassWizard will add and remove mapping macros here.
-)Hc^'. // DO NOT EDIT what you see in these blocks of generated code!
6&;h+;h //}}AFX_MSG_MAP
&)izh) FA END_MESSAGE_MAP()
Pm"nwm jct'B}@X( CHookApp::CHookApp()
yioX^`Fc(~ {
3Dx@rW\ // TODO: add construction code here,
&fW'_,- // Place all significant initialization in InitInstance
rV
fZ_\| }
.aQ8I1~ &N*l ?7( CHookApp theApp;
:7?n)=Tx LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
TDX~?>P {
Z# %s/TL BOOL bProcessed=FALSE;
=9;b|Y"aQ if(HC_ACTION==nCode)
>eWORf>7 {
i1 c[Gk.o if((lParam&0xc0000000)==0xc0000000){// Key up
84<zTmm switch(wParam)
uT>"(wnJ| {
N , ,[V
case VK_MENU:
%6la@i MaskBits&=~ALTBIT;
pf&U$oR4 break;
Z>[n~{-,p case VK_CONTROL:
p_i',5H( MaskBits&=~CTRLBIT;
Rh%A^j@ break;
Te `MIR case VK_SHIFT:
32Wa{LG;2 MaskBits&=~SHIFTBIT;
akG|ic-~ break;
sJMpF8
default: //judge the key and send message
/!sGO: break;
uANpqT}! }
3G'cDemc for(int index=0;index<MAX_KEY;index++){
n72kJ3u. if(hCallWnd[index]==NULL)
P?@o? continue;
!{CaW4 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
/m4Y87 {
Z=
=c3~ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
;(rK^*`fO bProcessed=TRUE;
:jJ0 +Q }
T%A"E,# }
&[
,* }
$h[Q}uW else if((lParam&0xc000ffff)==1){ //Key down
xyHv7u%* switch(wParam)
j
Y(|z*| {
UgD)O:xaU case VK_MENU:
$&Z<4:Flc MaskBits|=ALTBIT;
$RYOj{1 break;
I|Mw*2U case VK_CONTROL:
Lj/ MaskBits|=CTRLBIT;
Wiyiq )^ break;
$-.*8*9 case VK_SHIFT:
4ves|pLET MaskBits|=SHIFTBIT;
xZ(d*/6E break;
C}ASVywc,1 default: //judge the key and send message
fu?u~QZ8 break;
f ~bgZ }
-j@IDd7 for(int index=0;index<MAX_KEY;index++)
wxN&k$`a {
$~\Tl:!#? if(hCallWnd[index]==NULL)
R+2~%|{d continue;
N36B*9m&p if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
(hh^? {
a5&[O SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
EKS?3z%! bProcessed=TRUE;
b;nqhO[f} }
+11 oVW }
aimf,(+ }
wL}X~Xa3i if(!bProcessed){
k5*Z@a for(int index=0;index<MAX_KEY;index++){
h,6> ^A if(hCallWnd[index]==NULL)
#V$sb1u continue;
BU7QK_zT: if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
,1]VY/ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
=dmxE*C }
)<Mo. }
1bHQB$%z }
lTVz'ys return CallNextHookEx( hHook, nCode, wParam, lParam );
5DO}&%.xt }
d[*NDMO 4q(,uk&R[ BOOL InitHotkey()
R^]a<g, {
rv<qze;?| if(hHook!=NULL){
HGi%b5:<=M nHookCount++;
cVYu(ssC4 return TRUE;
jo<Gf 5 }
eLbh1L else
AP8J28I hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
2/Y e<.# if(hHook!=NULL)
qk>M~, nHookCount++;
;Wsl 'e/ return (hHook!=NULL);
vE)d0l" }
prB:E[1 BOOL UnInit()
db}lN {
j 20mZ if(nHookCount>1){
"{d[V(lE" nHookCount--;
&)|f|\yh" return TRUE;
CK_\K,xVT }
\`%#SmQF BOOL unhooked = UnhookWindowsHookEx(hHook);
'#~Sb8
if(unhooked==TRUE){
Ih;D-^RQ nHookCount=0;
u'gsIuRJ hHook=NULL;
}uO2x@ }
T+FlN-iy) return unhooked;
@V+KL>Qw }
@&9<)1F 3E>]6 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
IVeA[qA0 {
T( k:\z/ BOOL bAdded=FALSE;
jO`L:D/C for(int index=0;index<MAX_KEY;index++){
JD AX^] if(hCallWnd[index]==0){
6\%#=GG hCallWnd[index]=hWnd;
};*&;GFe HotKey[index]=cKey;
.
ywVGBvJ HotKeyMask[index]=cMask;
6+C]rEY/o
bAdded=TRUE;
ZB5NTNf> KeyCount++;
dbF9%I@ break;
6^FUuj. }
k\ZU%"^J }
LrV|Y~ return bAdded;
WckWX]};S }
:z$+leNH\ 6']WOM# BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
w2K>k/v{- {
Ac/LNqIs BOOL bRemoved=FALSE;
("=24R=a for(int index=0;index<MAX_KEY;index++){
9FF if(hCallWnd[index]==hWnd){
P{,=a]x,mz if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
T'N/A9{q hCallWnd[index]=NULL;
4*UKR!sr HotKey[index]=0;
!T}R=;)eh HotKeyMask[index]=0;
EclsOBg bRemoved=TRUE;
yW i?2
KeyCount--;
a
JQ_V break;
msw=x0{n5 }
ETfoL.d$( }
R5<:3tk=X }
,@Elw>^ return bRemoved;
=':B }
$- GwNG jfZ) void VerifyWindow()
^YEMR C {
6{ pg^K for(int i=0;i<MAX_KEY;i++){
5J3K3 if(hCallWnd
!=NULL){ FXid=&T@0D
if(!IsWindow(hCallWnd)){ `,FhCT5
hCallWnd=NULL; :/;;|lGw
HotKey=0; c2yZvi
HotKeyMask=0; K!gocNOf
KeyCount--; `V?NS,@$
}
_,*QJ
} ?C_Y2JY
} +^%0/0e
} :n oZ
p:a
.L_ Hk
BOOL CHookApp::InitInstance() ~8[`(/hj
{ "GAKi}y">v
AFX_MANAGE_STATE(AfxGetStaticModuleState()); u"kB`||(
hins=AfxGetInstanceHandle(); 2c5)pIVEy
InitHotkey(); Qs_]U
return CWinApp::InitInstance(); &"X1w $
} ~&+8m=
1(
]{tF
int CHookApp::ExitInstance() !GoHCe[10
{ `(@{t:L
VerifyWindow(); Vc
"+|^
UnInit(); Oi~.z@@
return CWinApp::ExitInstance(); gq)uv`3
} 7:OF>**
p[D,.0SuC
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file Bv}nG|
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) !]#;'
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ 2Vg+Aly4D
#if _MSC_VER > 1000 4I;$a;R!
#pragma once "%+9p6/
#endif // _MSC_VER > 1000 ?;p45y~n%
k
i{8f
class CCaptureDlg : public CDialog nsi&r
{ +\MGlsMK@.
// Construction f`p"uLNo<
public: qApf\o3[0
BOOL bTray; .OD{^Kq2
BOOL bRegistered; :z+l=d:4
BOOL RegisterHotkey(); Y!_e,]GW
UCHAR cKey; <7J\8JR&=
UCHAR cMask; wmFS+F4`2
void DeleteIcon(); ngH_p>
void AddIcon(); t8"yAYj
UINT nCount; w'P!<JaZ
void SaveBmp(); DgC;1U'
CCaptureDlg(CWnd* pParent = NULL); // standard constructor 6"jV>CNc@
// Dialog Data o,=dm@j
//{{AFX_DATA(CCaptureDlg) :-1
i1d
enum { IDD = IDD_CAPTURE_DIALOG }; h, P#)^"
CComboBox m_Key; b'G!)n
BOOL m_bControl; Z~DR,:
BOOL m_bAlt; "A&