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:
bra2xHK@
t`JT 一、实现方法
0OHXg= P;I,f 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:
#!Cg$6%x9 3 ~P$p< #pragma data_seg("shareddata")
g&g:HH: HHOOK hHook =NULL; //钩子句柄
.@&FJYkLYi UINT nHookCount =0; //挂接的程序数目
Wmd@%K static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
_|C3\x1c static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
h/\v+xiF static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
_K9PA[m5~ static int KeyCount =0;
3J"`mQ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
uY~mi9E #pragma data_seg()
oi0O4J%H n8EKTuy 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。
Ja3#W
K DLbP$&o DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
YeOn C,W@C BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
OG<*&V cKey,UCHAR cMask)
DL,R~ {
k H65k ( BOOL bAdded=FALSE;
p_Xfj2E4c for(int index=0;index<MAX_KEY;index++){
<o()14
if(hCallWnd[index]==0){
X{#^O/ hCallWnd[index]=hWnd;
Mt4]\pMUb HotKey[index]=cKey;
HCOsVTl, HotKeyMask[index]=cMask;
0t!ZMH bAdded=TRUE;
.'M.yE~5J KeyCount++;
5]*lH t break;
bq7+l4CGTv }
]xvhUv!G }
|iJz[% return bAdded;
(Yj6|` }
Q)aoc.f!v //删除热键
;0WAfu}#H BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
M{p6&eg {
! =21K0~t# BOOL bRemoved=FALSE;
'~b for(int index=0;index<MAX_KEY;index++){
Ut~YvWc9 if(hCallWnd[index]==hWnd){
C3 "EZe[R if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
<IR@/b!, hCallWnd[index]=NULL;
qsp3G7\'= HotKey[index]=0;
;fqp!|J HotKeyMask[index]=0;
LF.i0^#J bRemoved=TRUE;
X#axCDM- KeyCount--;
EO+Ix7w break;
3\ajnd| }
%rs2{Q2k }
Y_*KAr'{P }
@GAj%MK$ return bRemoved;
'dwsm7Xd }
5L6.7}B 9*iVv)jd 1N _"Mm{ DLL中的钩子函数如下:
[uqr }%wP^6G*x\ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
E7h@c>IK {
7V=deYt_p BOOL bProcessed=FALSE;
h(q4
B~ if(HC_ACTION==nCode)
lg-`zV3 {
KD#zsL)3 if((lParam&0xc0000000)==0xc0000000){// 有键松开
>;G_o="X switch(wParam)
d3E N0e+^ {
oa+'.b~ case VK_MENU:
dh]Hf,OLF MaskBits&=~ALTBIT;
<8%+-[(
break;
GX19GI@k case VK_CONTROL:
~C
3Y/} MaskBits&=~CTRLBIT;
q#Otp\f break;
q:up8-LAr case VK_SHIFT:
MV<)qa T MaskBits&=~SHIFTBIT;
(Ajhf}zJ break;
2pHR $GZ2 default: //judge the key and send message
Flpl,|n
a break;
ST#)Fl }
1;./e&%% for(int index=0;index<MAX_KEY;index++){
5D3&E_S if(hCallWnd[index]==NULL)
vyc<RjS_x continue;
d<?Zaehe\ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
:OU(fz] {
~+ae68{p SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
U'b}%[ bProcessed=TRUE;
\zVp8MMf }
eiOAbO#U }
z1RHdu0;z }
)e[q%%ks else if((lParam&0xc000ffff)==1){ //有键按下
_j$V[=kdM/ switch(wParam)
7 HL
Uk3 {
sk5=$My case VK_MENU:
([JFX@ MaskBits|=ALTBIT;
3mE8tTA$R break;
8fvKVS case VK_CONTROL:
2hntQ1[ MaskBits|=CTRLBIT;
:n<l0 break;
~>]Ie~E: ( case VK_SHIFT:
fX:G;vYn MaskBits|=SHIFTBIT;
Lo'GfHE break;
QncjSaEE default: //judge the key and send message
S%
ptG$Z break;
/q]fG }
B$=1@ for(int index=0;index<MAX_KEY;index++){
N+R{&v7=F% if(hCallWnd[index]==NULL)
lh0G/8+C continue;
#I ,c'Vj if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
brE%/%!e {
!`U #Pjp. SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
KPK`C0mg@k bProcessed=TRUE;
,iiI5FR }
%RIu'JXi }
$ ga,$G }
Pmuk !V}f if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
R $/q=*k for(int index=0;index<MAX_KEY;index++){
Nde1`W]: if(hCallWnd[index]==NULL)
99zMdo S continue;
('_S1?y if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
MmfshnTN SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
;h~k B //lParam的意义可看MSDN中WM_KEYDOWN部分
+ZwTi!W }
UA0R)BH' }
Dxr4B< }
!vr
A\d return CallNextHookEx( hHook, nCode, wParam, lParam );
W70BRXe04D }
IOrYm iee`Yg!EOH 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
Q>=/u- 48GaZ@v BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
usugjx^p BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
H'2o84$ yK2>ou
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:
+ L5 78mJ3/?rC LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
FP6JfI8 {
Zg])uM]\2i if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
3v~}hV/RUy {
dI,H:g //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
G~lnX^46" SaveBmp();
a'G[!" return FALSE;
[/cJc%{N }
d/?0xL W …… //其它处理及默认处理
K!88 Nox( }
n*=Tm
KQ RCGpZyl ~bjT,i 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。
y3 S T"U U%2{PbL
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。
xl,?Hh%# ^F"eHUg 二、编程步骤
i;+<5_ i\L7z)u 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";
M
w+4atO4[ G>^ _&(c@2 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
L!W5H2Mc 'Ya- ;5Y] 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;
n22OPvp Yceex}X*5 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;
7mS_Cz+cB 0vz!) 5、 添加代码,编译运行程序。
ubi6= Gc!&I+kd 三、程序代码
?rwHkPJ{* H!g9~a ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
zL:k(7E #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
%t-}dC& #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
H`U>ZJ. #if _MSC_VER > 1000
6FI`0j=~ #pragma once
/%^^hr #endif // _MSC_VER > 1000
Fc"+L+h@W #ifndef __AFXWIN_H__
O6!:Qd #error include 'stdafx.h' before including this file for PCH
m3b?f B #endif
1b"3]? #include "resource.h" // main symbols
3rv~r0 class CHookApp : public CWinApp
3n TpL# {
`X wKCI public:
+?[iB"F CHookApp();
v.]W{~PI2V // Overrides
htqC~B{1E // ClassWizard generated virtual function overrides
.`N&,&H //{{AFX_VIRTUAL(CHookApp)
I*
JSb9r public:
q}7(w$& virtual BOOL InitInstance();
fL R.2vJ virtual int ExitInstance();
ez *O'U //}}AFX_VIRTUAL
cU=/X{&Om //{{AFX_MSG(CHookApp)
[IuF0$w=dj // NOTE - the ClassWizard will add and remove member functions here.
|G>Lud // DO NOT EDIT what you see in these blocks of generated code !
=^3B&qQNq //}}AFX_MSG
Js8d{\0\ DECLARE_MESSAGE_MAP()
T;JA.=I };
F|W(_llfM LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
:j!N7c{ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
4}=Z+tDu> BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
d[Rs BOOL InitHotkey();
rexy*Xv`2p BOOL UnInit();
GI*2*m!u #endif
gNo}\
lm4V 2Y{r2m|o //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
_M}}H3 #include "stdafx.h"
!xZ`()D# #include "hook.h"
'4d+!%2t #include <windowsx.h>
qeZ*!H6- #ifdef _DEBUG
u'EzYJ7 #define new DEBUG_NEW
E@$HO_;& #undef THIS_FILE
c`G~.paY| static char THIS_FILE[] = __FILE__;
syLpnNx= #endif
n<>/X_m #define MAX_KEY 100
8Ow0A #define CTRLBIT 0x04
XB-l[4? #define ALTBIT 0x02
be{t yV
#define SHIFTBIT 0x01
< {dV= #pragma data_seg("shareddata")
.1& F p HHOOK hHook =NULL;
0(dXU\Y UINT nHookCount =0;
ns1@=f cO static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
n*fsdo~ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
5;-?qcb^w static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
f)K1j{TZ static int KeyCount =0;
8a4&}^| static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
E#cZM> #pragma data_seg()
.9;wJ9Bw[ HINSTANCE hins;
.EQ1r7
9, void VerifyWindow();
k%?A=h BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
vy330SQPo //{{AFX_MSG_MAP(CHookApp)
@=1kr ^i // NOTE - the ClassWizard will add and remove mapping macros here.
JdeGQ // DO NOT EDIT what you see in these blocks of generated code!
O:,Fif?; //}}AFX_MSG_MAP
]):kMRv END_MESSAGE_MAP()
.FXn=4l'vV DN;An0
{MK CHookApp::CHookApp()
?rgk {
C %o^AR // TODO: add construction code here,
gkyv[ // Place all significant initialization in InitInstance
V|8`]QW@ }
{$mj9?n=v #r_&Q`!eU CHookApp theApp;
#<|q4a{8 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
*6e 5T {
.)eX(2j\ BOOL bProcessed=FALSE;
^d2bl,1 if(HC_ACTION==nCode)
T&`H )o {
cU'^
Ja?% if((lParam&0xc0000000)==0xc0000000){// Key up
Lcyj,R switch(wParam)
Z,osdF {
|YAnd=$ case VK_MENU:
C7[CfcPA MaskBits&=~ALTBIT;
77ID
82 break;
4h[^!up.7 case VK_CONTROL:
GM<r{6Qy MaskBits&=~CTRLBIT;
&<sN(;%0R break;
Q@lJ| case VK_SHIFT:
G}b LWA MaskBits&=~SHIFTBIT;
J<{@D9r9<~ break;
wN
![SM/+ default: //judge the key and send message
bJE$> break;
M6b;
DQ }
Wg+fT{[f| for(int index=0;index<MAX_KEY;index++){
a~F`{(Q2 if(hCallWnd[index]==NULL)
j.@TPf* continue;
woqP&8a if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
CdRgI^5 {
lU<n Wf SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
`n!<h,S'2 bProcessed=TRUE;
V0h }
>@BvyZ)i }
"K8<X }
5b9>a5j1; else if((lParam&0xc000ffff)==1){ //Key down
-l!;PV S| switch(wParam)
QDC]g.x {
kEQ${F{ case VK_MENU:
@: s |X MaskBits|=ALTBIT;
X>#!s Lt break;
QxmVImn" case VK_CONTROL:
5!PU+9Kh MaskBits|=CTRLBIT;
m{bw(+r break;
H[{ch t
h case VK_SHIFT:
<eq93 MaskBits|=SHIFTBIT;
0r+%5}|-K break;
uz1t uX_ default: //judge the key and send message
c!BiGw,; break;
W1s4[rL!Ht }
.hCOi<wB for(int index=0;index<MAX_KEY;index++)
:B<lDcFKJ {
5"[Qs|VjA6 if(hCallWnd[index]==NULL)
&OiJJl[9 continue;
l }?'U if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
UEJX0= {
}>w;(R SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
0FHX bProcessed=TRUE;
ba 3_55] }
;!k1LfN }
*p.P/w@1 }
yp=2nU"o if(!bProcessed){
MOFIR
wVZ+ for(int index=0;index<MAX_KEY;index++){
^6~CA if(hCallWnd[index]==NULL)
Xa2QtJq continue;
$zTjh~ 9 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
wL2d.$?TEg SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
CW Y'q }
tF)aNtX4^ }
}Jgz#d }
]y,6 return CallNextHookEx( hHook, nCode, wParam, lParam );
:G|Jcl=r }
@Zs}8YhC 1e;^MzB" BOOL InitHotkey()
-,~n|ceI {
(d[)U< if(hHook!=NULL){
^z$-NSlI nHookCount++;
MS6^= [" return TRUE;
{O6f1LuH }
?<Dinq else
*N$#cz
hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
tLpDIA_8 if(hHook!=NULL)
4
~17s`+ nHookCount++;
ejwFQ'wTx return (hHook!=NULL);
67Ai.3dR }
H;<hmbN?d BOOL UnInit()
h]<Ld9 {
[KR`%fD0 if(nHookCount>1){
#nc{MR#R nHookCount--;
+gTnq")wnI return TRUE;
c8gdY` }
A8OV3h6] BOOL unhooked = UnhookWindowsHookEx(hHook);
S*:b\{[f> if(unhooked==TRUE){
;""V s6 nHookCount=0;
v"L<{HN hHook=NULL;
2Ni$
(`" }
4ow)vS( return unhooked;
"qb3\0O }
_.Y?BAQ Xb42R1 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
D:llGdU#2 {
j]6j!.1 BOOL bAdded=FALSE;
POc<
G^ for(int index=0;index<MAX_KEY;index++){
~l-Q0wg if(hCallWnd[index]==0){
"}|n;:r hCallWnd[index]=hWnd;
Hq^sU% HotKey[index]=cKey;
>U9* HotKeyMask[index]=cMask;
r9G<HKl bAdded=TRUE;
TE0hVw0c KeyCount++;
g!<@6\RB break;
.8CR
\- }
LZyUlz }
lC.Yu$O5 return bAdded;
@Q3aJ98)2 }
g^1M]1.f j ij:}.d6 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
jR\T\r4 {
k:<yy^g$X BOOL bRemoved=FALSE;
"-vm=d~\ for(int index=0;index<MAX_KEY;index++){
r 9@W8](\ if(hCallWnd[index]==hWnd){
j%b/1@I if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
O GrVy=rd hCallWnd[index]=NULL;
[,-MC7>] HotKey[index]=0;
#P-S.b HotKeyMask[index]=0;
W z3y+I/& bRemoved=TRUE;
'uBW1, KeyCount--;
vI#\Qe break;
#OH-LWZh }
D2~e@J(K }
H__9%p# }
K3TMT Y<p return bRemoved;
M=e]v9
}
w:&m_z#M C2,,+* v void VerifyWindow()
cxrUk$f {
3t(nV4uDF for(int i=0;i<MAX_KEY;i++){
./)A6O*# if(hCallWnd
!=NULL){ %?_pSH}$!
if(!IsWindow(hCallWnd)){ KQ xKU?b1
hCallWnd=NULL; 1,Uv;s;{
HotKey=0; x\!Qe\lE
HotKeyMask=0; )`^t,x<S
KeyCount--; d$kGYMT"
} s*:J=+D]G
} "W|Sh#JF
} 3IZ^!J
} 7Rk eV
$TL~SVHj;{
BOOL CHookApp::InitInstance() DTt/nmKAqJ
{ #~q{6()e:
AFX_MANAGE_STATE(AfxGetStaticModuleState()); g%#"
5Kr
hins=AfxGetInstanceHandle(); ! SD?
InitHotkey(); >.SU=HG;
return CWinApp::InitInstance(); 1/3Go97/qV
} B+wSLi(
Io{)@H"f
int CHookApp::ExitInstance() @X"p"3V
{ 4\Y2{Z>P?
VerifyWindow(); %.BbPR 7?h
UnInit(); a{QHv0goG
return CWinApp::ExitInstance(); %s%v|HDs
} AIF?+i%H}
jhUab],
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file pA+W
8v#*
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) sbrU;X_S
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ x;l\#x/<
#if _MSC_VER > 1000 "ZNiTND
#pragma once P(d4~hS
#endif // _MSC_VER > 1000 $985q@pV0
<jQ?l%\
class CCaptureDlg : public CDialog 9@#Z6[=R,
{ u} JL*}Q
// Construction ^LE`Y>&m
public: j\("d4n%C
BOOL bTray; $OHY^IE(
BOOL bRegistered; SY["dcx+
BOOL RegisterHotkey(); .:*V
CDOM
UCHAR cKey; nfq
UCHAR cMask; g9H~\w
void DeleteIcon(); vdYd~>w
void AddIcon(); {%'(IJ|5z
UINT nCount; ]YQlCx`
void SaveBmp(); (01M 0b#
CCaptureDlg(CWnd* pParent = NULL); // standard constructor ~C{d2i
// Dialog Data bPAp0}{Fu
//{{AFX_DATA(CCaptureDlg) :O{`!&[>L
enum { IDD = IDD_CAPTURE_DIALOG }; *{P"u(K
CComboBox m_Key; ,o]"G[Jk
BOOL m_bControl; k+{-iPm{
BOOL m_bAlt; >o>r@;
BOOL m_bShift; 4WG~7eIgy
CString m_Path; !uii|"
CString m_Number; @3K)VjY7
//}}AFX_DATA 5u
MP31
// ClassWizard generated virtual function overrides 4$+1jjC]>~
//{{AFX_VIRTUAL(CCaptureDlg) _y#t[|}w
public: p-GlGEt_X
virtual BOOL PreTranslateMessage(MSG* pMsg); -]~&Pi