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:
s@8w-]"
;"kaF! 一、实现方法
&c>?~-!W LzML%J62 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:
nhT-Ido c9wfsapJ #pragma data_seg("shareddata")
.ubE2X[ ][ HHOOK hHook =NULL; //钩子句柄
EON:B>2a UINT nHookCount =0; //挂接的程序数目
.uF[C{RnO static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Ts.wh>` static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
$pyOn2} static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
i/H+xrCK static int KeyCount =0;
]QVNn?PA8 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
^uBxgWIC #pragma data_seg()
rHjq1-t >UDd @ 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
UC
HZ2& ;G\8jP'
DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
Wp)*Mbq@ 0@I S BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
CVNj-&vj cKey,UCHAR cMask)
6$\jAd| {
?e[lr>- BOOL bAdded=FALSE;
QnQOm"" for(int index=0;index<MAX_KEY;index++){
U8.7>ENnP& if(hCallWnd[index]==0){
@$9'@") hCallWnd[index]=hWnd;
+{<#(} HotKey[index]=cKey;
J(DN! HotKeyMask[index]=cMask;
EU7|,>a bAdded=TRUE;
-m
*Sq KeyCount++;
5"XC$?I<} break;
_g%TSumvq< }
Q7Iw[=;\ }
6AG`&'" return bAdded;
M?m,EQh. }
|a1{ve[ //删除热键
oND@:>QBF BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
b 5yW_Ozdh {
(T`E!A0I\? BOOL bRemoved=FALSE;
Ym%xx!9 for(int index=0;index<MAX_KEY;index++){
o1M$.* if(hCallWnd[index]==hWnd){
"&/-N[is if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
P3$Q&^? hCallWnd[index]=NULL;
.<@8gNm3 HotKey[index]=0;
iQDx{m3] HotKeyMask[index]=0;
vz.>~HBP bRemoved=TRUE;
y;_% W KeyCount--;
F*"}aP$ break;
-py@DzK }
F~h7{@\ }
~e6Brq }
/c
uLc^(X return bRemoved;
EoK~S\dS }
Z#rB} 0c} }Q :POj6j/ DLL中的钩子函数如下:
%CK^Si%+ CrwwU7qKL LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
?@E!u|]K {
ty8v
6J# BOOL bProcessed=FALSE;
dqN5]Sb2B if(HC_ACTION==nCode)
&mb{.= {
Ii G6<|d8H if((lParam&0xc0000000)==0xc0000000){// 有键松开
#B4%|v;`E? switch(wParam)
/`mks1:pK {
#Y$hNQQ$F case VK_MENU:
\otWd MaskBits&=~ALTBIT;
l<A|d{" ] break;
ZMel{w`n case VK_CONTROL:
ax (c# MaskBits&=~CTRLBIT;
3\XU_Xs(] break;
S:OO0<W case VK_SHIFT:
H ' MaskBits&=~SHIFTBIT;
8uWa=C) break;
B]Thn default: //judge the key and send message
0N$v"uX@ break;
U|IzXQX( }
>k (C for(int index=0;index<MAX_KEY;index++){
k7T`bYv if(hCallWnd[index]==NULL)
MRdduPrM%$ continue;
%^ !,t:d if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
[k/@E+; {
YB2VcF.LU SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
s+<Yg$) bProcessed=TRUE;
`Tv[DIVW }
V6@o]* }
]GW]dM }
E>D_V@,/ else if((lParam&0xc000ffff)==1){ //有键按下
Jcrw#l8|C switch(wParam)
L6|oyf {
Pu" P9 case VK_MENU:
toBHkiuD MaskBits|=ALTBIT;
NgP&.39U break;
|R/%D%_g case VK_CONTROL:
RO'7\xvn MaskBits|=CTRLBIT;
U_I5fK= break;
;z $(nhJ case VK_SHIFT:
kY-N>E: MaskBits|=SHIFTBIT;
]QlwR'&j/n break;
<^5Z:n!q default: //judge the key and send message
P*3BB>FO break;
$#9;)8J }
/} b03 for(int index=0;index<MAX_KEY;index++){
+ |n*b if(hCallWnd[index]==NULL)
s;01u_ continue;
/rnu<Q#iH if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
*Doa*wQ {
VJ]JjB
j SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
$QLcH;+7t bProcessed=TRUE;
svcK?^
HTe }
0=2@ }
3KlbP }
A>o*t=5 if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
+M\`#i\g> for(int index=0;index<MAX_KEY;index++){
5m&9"T. w if(hCallWnd[index]==NULL)
iTgt}]L continue;
keL&b/@ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
4%>$-($ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
R;uvkg[o //lParam的意义可看MSDN中WM_KEYDOWN部分
< $lCkSx<Q }
hK L4cpK4 }
yerg=,$_i }
Jh,]r?Bd return CallNextHookEx( hHook, nCode, wParam, lParam );
1ySk;;3 }
Hq:X{)" f
e\$@- 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:
4xjP iHd< /R]U}o^/(% BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
ayR-\mZ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
GfoLae snE8 K}4 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:
t5\-v_mG=& s~ a"4~f LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
U)fc*s {
[B\h$IcRv if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
yVU^M?`# {
4gI/!,J(b //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
9-&Ttbb4)0 SaveBmp();
x kx^%3dV return FALSE;
tqE6>"jD }
_{I3i:f9X8 …… //其它处理及默认处理
+~m46eI }
0L2 F[TN Elcj tYu4 o4G ?nvK- 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。
e'6/`Evqz oK6tTK 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。
PxWT1 ! KKja/p 二、编程步骤
(y=C_wvqZ =upeRY@u5 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";
! ` > kGGR 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
T"{>t j/323Za+ 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;
&FMc?wq tU }h~&M 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;
132{#tG] Si2k"<5U 5、 添加代码,编译运行程序。
%aG5F}S2~ q<xCb%#Jl 三、程序代码
=)0,#9k U] YqhAZp< ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
s 1A.+ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
$Xv* ,Bq #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
q( #if _MSC_VER > 1000
B]nEkO'a: #pragma once
K[I=6 #endif // _MSC_VER > 1000
}MJy
+Z8& #ifndef __AFXWIN_H__
5kc/Y/4o #error include 'stdafx.h' before including this file for PCH
}^ApJS(FQ #endif
1!xQ=DU" #include "resource.h" // main symbols
'F+C4QAq class CHookApp : public CWinApp
Nyku4r0 {
7-bd9uVK public:
$SlIr<'*" CHookApp();
j8v8uZ;x // Overrides
,;EIh} // ClassWizard generated virtual function overrides
z Xg3[orF //{{AFX_VIRTUAL(CHookApp)
0M_ DB= public:
ISYXH9V virtual BOOL InitInstance();
[;n9:Qxf virtual int ExitInstance();
[>jbhV' //}}AFX_VIRTUAL
Mo|;'+ //{{AFX_MSG(CHookApp)
iOd&BB6 // NOTE - the ClassWizard will add and remove member functions here.
hi_NOx // DO NOT EDIT what you see in these blocks of generated code !
}s7$7 //}}AFX_MSG
:y'Ah# DECLARE_MESSAGE_MAP()
\o z#l'z };
Y>dF5&(kb LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
&C`Gg< BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
3atBX5 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
DwM)r7<Ex BOOL InitHotkey();
n<Z({\9&H BOOL UnInit();
4GkWRu1 #endif
GSoX<*i 8v:T.o;< //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
.T}Wdng #include "stdafx.h"
DBo%fYst #include "hook.h"
M,j U}yD3 #include <windowsx.h>
X2#2C/6#u #ifdef _DEBUG
W =D4r #define new DEBUG_NEW
!44/sr' #undef THIS_FILE
j
b!x: static char THIS_FILE[] = __FILE__;
0CZ:Bo[3 #endif
]3D0R; #define MAX_KEY 100
G~F b #define CTRLBIT 0x04
tP:lP#9 #define ALTBIT 0x02
Z_LFIz*c #define SHIFTBIT 0x01
`fA@hK
#pragma data_seg("shareddata")
NN%*b yK HHOOK hHook =NULL;
|-fgj' UINT nHookCount =0;
.UQzPnK static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
*l"T$H static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
qSM|hHDo) static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
_?-E7:Sw static int KeyCount =0;
U'k*_g static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
oK9( /v #pragma data_seg()
;dkYf24 HINSTANCE hins;
a[>/h3 void VerifyWindow();
&DS/v)] BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
4svBzZdr //{{AFX_MSG_MAP(CHookApp)
]{sU&GqBLe // NOTE - the ClassWizard will add and remove mapping macros here.
7!$Q;A // DO NOT EDIT what you see in these blocks of generated code!
|'e^QpU5 //}}AFX_MSG_MAP
)Oq|amvC END_MESSAGE_MAP()
Z]A{ d[ sZ3KT& CHookApp::CHookApp()
lXx=But {
]MqMQLG0t // TODO: add construction code here,
IDad9 Bx // Place all significant initialization in InitInstance
7!evm;A }
sSr&:BOsi ~Z -Vs CHookApp theApp;
`vU%*g&R LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
;"xfOzQ {
272q1~& BOOL bProcessed=FALSE;
A9[ F if(HC_ACTION==nCode)
E`kG-Q5Dw {
n"h`5p5' if((lParam&0xc0000000)==0xc0000000){// Key up
6gkV*|U,e switch(wParam)
Bm:98? [ {
FXpJqlhNv case VK_MENU:
kC:uG0sW MaskBits&=~ALTBIT;
I!ED?n break;
55G+; case VK_CONTROL:
)~&CvJ MaskBits&=~CTRLBIT;
;/bewivNJ break;
%gInje case VK_SHIFT:
S:u:z=:r MaskBits&=~SHIFTBIT;
=R^%(Py break;
g6yB6vk default: //judge the key and send message
L s
G\OG break;
):P? }
gLb`pCo/ for(int index=0;index<MAX_KEY;index++){
Mhm@R@ if(hCallWnd[index]==NULL)
@tF\p
continue;
&U{#Kt5q if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
EHSlK5bD, {
/~DI 6g SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
2kqu p)82e bProcessed=TRUE;
_;W.q7b] }
a y4 % }
u/UrAqw }
-Sqz5lo else if((lParam&0xc000ffff)==1){ //Key down
G5{T5# switch(wParam)
LY+@o<> {
*HU &4E\a case VK_MENU:
bes<qy MaskBits|=ALTBIT;
pLl(iNf] break;
yyR0]NzYUD case VK_CONTROL:
)Fc%+TpKi MaskBits|=CTRLBIT;
&`h{iK7 break;
.4S.>~^7 case VK_SHIFT:
f<GhkDPm>? MaskBits|=SHIFTBIT;
NxfOF break;
{0r0\D>bw default: //judge the key and send message
bUs0 M0y break;
i)\L:qF5 }
zlyS}x@p for(int index=0;index<MAX_KEY;index++)
$5>e {
3N8t`N if(hCallWnd[index]==NULL)
RXNn[A4xfY continue;
9q)Kfz if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
7 G)ZN{' {
j
'FVz& SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
B)$| vK= bProcessed=TRUE;
Ig$(3p
}
uMUBh 80,L }
FW.7'7G@n }
[m+2(I1 if(!bProcessed){
Mc@e0 for(int index=0;index<MAX_KEY;index++){
M\vwI" if(hCallWnd[index]==NULL)
Y21g{$~Q{ continue;
Qd)q([ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
%W'v}p SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
JELTo u }
0Vj4+2?L5; }
o\BOL3H }
EJj.1/]|r return CallNextHookEx( hHook, nCode, wParam, lParam );
]E7F/O/. }
9 *xR6 H-WJp<_ BOOL InitHotkey()
XND|h#i8 {
vGvf<ra;H if(hHook!=NULL){
#TeG-sFJg@ nHookCount++;
9eR-
return TRUE;
]5mn ew }
iM AfJ-oN else
EH$1fvE hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
6O|@xvg if(hHook!=NULL)
{mm)ay|M nHookCount++;
t\?ik6 return (hHook!=NULL);
iyA'#bE- }
kC WEtbz1 BOOL UnInit()
"C}b%aO: {
:C7_Jp*Qv if(nHookCount>1){
;"KJ7p nHookCount--;
B%"
d~5Y return TRUE;
eds o2 }
O80<Z#%j` BOOL unhooked = UnhookWindowsHookEx(hHook);
3Ko/{f if(unhooked==TRUE){
l2`s! ,<>O nHookCount=0;
//*fSF hHook=NULL;
|"?M 1*g }
DD7h^-x return unhooked;
ccB&O _ }
_?<|{O 3?[dE< BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Jy^u? {
qJ;jfh! BOOL bAdded=FALSE;
a<@1-j< for(int index=0;index<MAX_KEY;index++){
KmMzH`t}` if(hCallWnd[index]==0){
M:XSQ["6>V hCallWnd[index]=hWnd;
?Fi=P# HotKey[index]=cKey;
c(J!~7 HotKeyMask[index]=cMask;
#eQJEajv5 bAdded=TRUE;
c$ao:nP)D KeyCount++;
QU4h8}$ break;
FFV `P }
h xSKG }
`lQ3C{} return bAdded;
ks"|}9\%< }
t,,k
rw: c BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
x8wD0D {
W6f/T3 BOOL bRemoved=FALSE;
!5.8]v for(int index=0;index<MAX_KEY;index++){
L\Aq6q@c if(hCallWnd[index]==hWnd){
Hx#;Z if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
`q?8A3A hCallWnd[index]=NULL;
;LcVr13J/ HotKey[index]=0;
%4ePc- HotKeyMask[index]=0;
9zZr^{lUl bRemoved=TRUE;
0":ib0= KeyCount--;
?$vCW|f break;
kv3E4,<9 }
e]`[yf }
%oq{L]C(rf }
, 0imiv return bRemoved;
=5Q]m6-SgV }
g>Y|9Y jNTjSX void VerifyWindow()
3
N.~mR {
/h+8A', for(int i=0;i<MAX_KEY;i++){
?6Jx@ Sh if(hCallWnd
!=NULL){ Inn@2$m~
if(!IsWindow(hCallWnd)){ &Nj3h(Ll
hCallWnd=NULL; (}a8"]Z
HotKey=0; ^=T$&gD
HotKeyMask=0; SNfr"2c'h~
KeyCount--; |s"nM<ZNZ
} *i]=f6G
} }'""(,2
} #OIcLEn%
} k,'L}SK
A9f)tqbc
BOOL CHookApp::InitInstance() ZNf6;%oGG
{ WP?TX b`5
AFX_MANAGE_STATE(AfxGetStaticModuleState()); } ~h3c|
hins=AfxGetInstanceHandle(); ZYI{i?Te#
InitHotkey(); d\p,2
return CWinApp::InitInstance(); 9S-Z&2L
} N03HQp)g
L$9.8W
int CHookApp::ExitInstance() #.it]Nv{
{ M:-.o
VerifyWindow(); ,RJtm%w
UnInit(); T,]7ICF#
return CWinApp::ExitInstance(); x$IX5:E#e
} Y,WuBH
?3*l{[@J
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file {p;zuCF1
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) lp<g\
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ zhpx"{_
#if _MSC_VER > 1000 4kG,*3&2
#pragma once qR(\5}
#endif // _MSC_VER > 1000 m1),;RsH
IIg^FZ*]_
class CCaptureDlg : public CDialog MOsl_^c
{ T?
tG~
// Construction w9NHk~LHKF
public: & @s!<9$W
BOOL bTray; eln&]d;
BOOL bRegistered; dE:+k/
BOOL RegisterHotkey(); Ko;{I?c
UCHAR cKey; MP_'D+LS
UCHAR cMask; G>wqt@%r9
void DeleteIcon(); %%NlTE8*
void AddIcon(); &Rx{.9
UINT nCount; Fe]B&n
void SaveBmp(); 5#> 8MU?&
CCaptureDlg(CWnd* pParent = NULL); // standard constructor u#Z#)3P
// Dialog Data zY,r9<I8_x
//{{AFX_DATA(CCaptureDlg) p /#$io
enum { IDD = IDD_CAPTURE_DIALOG }; c}y [[EX
CComboBox m_Key; /h*>P:i].
BOOL m_bControl; 5D_fXfx_|
BOOL m_bAlt; T-5nB>)
BOOL m_bShift; uM_#
CString m_Path; 5$wpL(:R(
CString m_Number; 3H|_mX
//}}AFX_DATA 3E>frR\!I
// ClassWizard generated virtual function overrides h&Efg