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:
AhZ`hj
$`2rtF 一、实现方法
%uuh+@/&yz )JO#Z( 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:
ArFsr Kk}|[\fW #pragma data_seg("shareddata")
m3apeIEi[ HHOOK hHook =NULL; //钩子句柄
h\oAW?^ UINT nHookCount =0; //挂接的程序数目
~wMdk9RQ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Bs@!S? static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
g>lJZD@ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
hi{#HXa static int KeyCount =0;
c)d*[OI8 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
v^Eg ,&( #pragma data_seg()
jRswGMx &C~R* 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。
/Hox]r]'e iqzl (9o.D 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:
vyME oD$8( BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
*K9I+t"g cKey,UCHAR cMask)
U4DQ+g(A {
0W asE1t| BOOL bAdded=FALSE;
[-Zp[ for(int index=0;index<MAX_KEY;index++){
E+Jh4$x{ if(hCallWnd[index]==0){
4G:I VK9 hCallWnd[index]=hWnd;
~?V+^<P HotKey[index]=cKey;
?_\t7f HotKeyMask[index]=cMask;
>^1|Mg/!> bAdded=TRUE;
hSxlj7Eo^T KeyCount++;
R W=<EF& break;
6GxQ< }
y$n7'W6 }
[m9Pt]j@
return bAdded;
]L'FYOfrpx }
U({20 //删除热键
H-?wEMi)*u BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
h'i8o>7 {
W\(u1>lj BOOL bRemoved=FALSE;
+3HukoR( for(int index=0;index<MAX_KEY;index++){
4?#0fK if(hCallWnd[index]==hWnd){
u!k]Q#2ZR if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
<b-BJ2],k hCallWnd[index]=NULL;
,BK6a'1J HotKey[index]=0;
|4UU`J9M HotKeyMask[index]=0;
<@BzF0 bRemoved=TRUE;
"[` .I*WNo KeyCount--;
'C
l}IDF break;
rAc
Yt9M# }
sU
{' }
%5N;SRtv }
@WppiZ$ return bRemoved;
R&z) }
qz|`\^ )+^1QL .g CC$ DLL中的钩子函数如下:
x^UE4$oo E$$pO.\ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Mo+mO&B {
NDG3mCl BOOL bProcessed=FALSE;
r]XXN2[jO if(HC_ACTION==nCode)
5e!YYt> {
@ljvTgZ(X if((lParam&0xc0000000)==0xc0000000){// 有键松开
%ZNp switch(wParam)
-1tdyCez {
OD,"8JF case VK_MENU:
|!r.p_Zt MaskBits&=~ALTBIT;
cJEOwAN break;
/?POIn+0o case VK_CONTROL:
LPjsR=xi MaskBits&=~CTRLBIT;
DVu_KT[H d break;
+O<0q"E case VK_SHIFT:
!B= Oc!e=K MaskBits&=~SHIFTBIT;
;WQ@dC break;
"J0,SFu: default: //judge the key and send message
; Q-f6)+& break;
fIrl?X'] }
x\=2D<@az for(int index=0;index<MAX_KEY;index++){
m6%csh-N1 if(hCallWnd[index]==NULL)
eqt+EiH continue;
+k!Y]_&(:f if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
r]x;JBy {
<
V?CM(1C SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
B]PTe~n^ bProcessed=TRUE;
H'Mc]zw_, }
zj!&12w%3 }
$#4J^(I*: }
5XO eYO{ else if((lParam&0xc000ffff)==1){ //有键按下
,"U8Fgf[r switch(wParam)
!/4f/g4Ze {
>Z#=< case VK_MENU:
Wsn}Y-x MaskBits|=ALTBIT;
RP]hW{:U break;
1vcI`8%S+u case VK_CONTROL:
KtWG2 MaskBits|=CTRLBIT;
]w _,0q break;
lYlU8l5> case VK_SHIFT:
stnyJ9 MaskBits|=SHIFTBIT;
lO/<xSjNd break;
By=/DVm)= default: //judge the key and send message
qyP|`Pm4 break;
oE+s8Q }
2 }QD> for(int index=0;index<MAX_KEY;index++){
0y$aGAUm if(hCallWnd[index]==NULL)
sPCp20x:y8 continue;
9`J!]WQ1[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
8ALvP}H {
-e=p*7'] SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
LGN,8v<W( bProcessed=TRUE;
/Kmzi9j+ }
ETP}mo }
d*26;5~\ }
M\wIpRD, if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
xCH,d:n= for(int index=0;index<MAX_KEY;index++){
L[zg2y if(hCallWnd[index]==NULL)
eSZS`(#!( continue;
B;'Dh<J1 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
cH>rS\|Y SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
:uZfdu //lParam的意义可看MSDN中WM_KEYDOWN部分
fH.:#O: }
%K^l]tWa@ }
|irqv< r }
dw)SF, return CallNextHookEx( hHook, nCode, wParam, lParam );
%?^T^P }
$|v_ pjUu] W4yNET%l, 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
|]a=He; @Taj++ua BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
&z;;Bx0s BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
[@ ]f@Wd OE(H:^ZR 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
!FweXFl %H:uE*WZ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
hWK}] gF {
q!#e2Dx if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
vjG:
1|*e {
Sf>R7.lpP //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
?PNG@OK SaveBmp();
!Gu,X'#Ab return FALSE;
-If-c'"G }
`fEB,0j^ …… //其它处理及默认处理
U^4
/rbQ }
SCl$+9E ./@!k[ :+ef|,:`/ 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。
lkf(t&vL2 .gNWDk0$Y 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
]%I cUd} >=hOjV; 二、编程步骤
UhCE.#
U -f0Nb+AR 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
jR@j+p^e X>mY`$!/
2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
R}F0_. !RLg[_' 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;
y@[}FgVOh G l+[|?N 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;
k LVf}J~? _Zya GDv 5、 添加代码,编译运行程序。
uhL+bj+W H4LZNko 三、程序代码
kVs'>H@FY =>Y b~r71 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
O"4Q=~Y #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
^yUel.N5" #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
l%*KBME #if _MSC_VER > 1000
ryzz!0l #pragma once
c0]^V>}cl #endif // _MSC_VER > 1000
c[]_gUp8 #ifndef __AFXWIN_H__
; >3q@9\D #error include 'stdafx.h' before including this file for PCH
i(9=` A} #endif
v_f8zk #include "resource.h" // main symbols
~lMw*Qw^ class CHookApp : public CWinApp
_aVrQ@9 {
OaU-4
~n; public:
mxtLcG4G CHookApp();
&P&LjHFK // Overrides
V6"<lK8" // ClassWizard generated virtual function overrides
#|fa/kb~ //{{AFX_VIRTUAL(CHookApp)
h+Km | public:
4g]Er<-P virtual BOOL InitInstance();
?Y2ZqI virtual int ExitInstance();
|ofegO}W7 //}}AFX_VIRTUAL
-x2/y:q ` //{{AFX_MSG(CHookApp)
5k.NZ // NOTE - the ClassWizard will add and remove member functions here.
*@fR36 // DO NOT EDIT what you see in these blocks of generated code !
FX7=81**4 //}}AFX_MSG
T9]|*~ ,T DECLARE_MESSAGE_MAP()
a&~_ba+ };
/W'GX n LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
U'zW; Lt BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
}^WQNdws56 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Ei2Y)_ BOOL InitHotkey();
78>)<$+d BOOL UnInit();
an^"_#8DA@ #endif
^'i(@{{o\ `;b@a<Wl //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
{4Y@DQ- #include "stdafx.h"
p+U}oC #include "hook.h"
\]}|m<R #include <windowsx.h>
1a3rA #ifdef _DEBUG
T6JN@:8 #define new DEBUG_NEW
FR9qW$B #undef THIS_FILE
V0 x[sEW static char THIS_FILE[] = __FILE__;
#}L75 #endif
K^`3Bg #define MAX_KEY 100
#k8bZ?*: #define CTRLBIT 0x04
0ZPwEP #define ALTBIT 0x02
xaSvjc\ #define SHIFTBIT 0x01
pkpD1c^ #pragma data_seg("shareddata")
-_Pd d[M HHOOK hHook =NULL;
QlJ
cj+_h UINT nHookCount =0;
,ii*[{X? static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
0F-X.Dq static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
1C\OL!@L static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
D_
xPa static int KeyCount =0;
!TY9\8JzV static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
^]w!ow41 #pragma data_seg()
;vvO#3DWM HINSTANCE hins;
24PEt%2 void VerifyWindow();
,80qwN, BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
/e :V44 //{{AFX_MSG_MAP(CHookApp)
>f #P( // NOTE - the ClassWizard will add and remove mapping macros here.
D].!u{## // DO NOT EDIT what you see in these blocks of generated code!
T:q_1W?h] //}}AFX_MSG_MAP
~4h<nc END_MESSAGE_MAP()
6s\niro2 BDSZ ' CHookApp::CHookApp()
){`s&? M0 {
Kk1 591' // TODO: add construction code here,
HQ~`ha. // Place all significant initialization in InitInstance
%JM:4G|q }
~K}iVX $2qZds[ CHookApp theApp;
R06L4,/b LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
$X8(OS5d' {
,#[0As29u BOOL bProcessed=FALSE;
tFt56/4 if(HC_ACTION==nCode)
zY~ {
ZC 7R f if((lParam&0xc0000000)==0xc0000000){// Key up
~Q"3#4l switch(wParam)
^;jJVYx-PP {
^T@ (`H4@ case VK_MENU:
4Gs#_|! MaskBits&=~ALTBIT;
yQE|FbiA break;
.gTla case VK_CONTROL:
&v|Uy}h&%1 MaskBits&=~CTRLBIT;
"*W: break;
vdw5T&Q{{C case VK_SHIFT:
^Gt&c_gH MaskBits&=~SHIFTBIT;
x8k7y: break;
HE58A.Q& default: //judge the key and send message
<WFA3 break;
G n"]<8yl~ }
|N_tVE for(int index=0;index<MAX_KEY;index++){
m3W:\LTTp if(hCallWnd[index]==NULL)
>QO^h<.> continue;
)3# gpM if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Fw5|_@&k {
X{4jyi-< SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
/a.4atb0 bProcessed=TRUE;
?q a }
|U{9Yy6p }
F: %-x=q }
l?pF?({ else if((lParam&0xc000ffff)==1){ //Key down
pgbm2mT9 switch(wParam)
4?Pdld {
EdFCaW}"" case VK_MENU:
>KHR;W 03 MaskBits|=ALTBIT;
0/K?'&$yvb break;
u3 k% case VK_CONTROL:
]j> W9n? MaskBits|=CTRLBIT;
hkV;(Fr&z break;
0WT]fY?IS case VK_SHIFT:
S:)Aj6>6 MaskBits|=SHIFTBIT;
]D?// break;
su;u_rc, default: //judge the key and send message
R<.<wQ4I break;
2%| }
G8=2=/ ! for(int index=0;index<MAX_KEY;index++)
j1{|3#5V {
~C[p}MED if(hCallWnd[index]==NULL)
gGF]Dq continue;
p3>(ZWPNV if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
n%'M?o]DF {
TNe,'S,% SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
ZrY#B8 bProcessed=TRUE;
p}q27<O*/ }
$ N`V%<W }
9U[Gh97Sf }
|dIP &9 if(!bProcessed){
hRAI7xk for(int index=0;index<MAX_KEY;index++){
7P1G^) if(hCallWnd[index]==NULL)
a&:1W83 continue;
9V&}% if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
%Aaf86pkp SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Mx9#YJ?t~ }
+B(x:hzY9 }
+&hhj~I. }
]xGo[:k|E return CallNextHookEx( hHook, nCode, wParam, lParam );
5ncjv@Aa }
*+(t2!yFmE EWOS6Yg7 BOOL InitHotkey()
l
e+6;'Q {
S&/</% if(hHook!=NULL){
3#GZ6:rVJ nHookCount++;
aD)$aK return TRUE;
48%-lkol) }
oh*Hzb else
m$N`Xj hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
wq yw#)S if(hHook!=NULL)
@ig'CF%( nHookCount++;
\s_lB~"P!3 return (hHook!=NULL);
=$ bJ`GpJ }
fP 1V1ao BOOL UnInit()
vTnrSNdSE {
(Hk4~v6pqC if(nHookCount>1){
%
mP%W< nHookCount--;
'{]1!yMh return TRUE;
E/bIq}R6 }
K:!){a[ BOOL unhooked = UnhookWindowsHookEx(hHook);
Xge]3Ub if(unhooked==TRUE){
J%VcvBaJm nHookCount=0;
0$=Uhi
hHook=NULL;
?O(@BT }
BR&T,x/d return unhooked;
]5(T{ }
UI:YzR pe^hOzVv BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
5L ]TV\\ {
mCM7FFl I BOOL bAdded=FALSE;
{
'A`ram for(int index=0;index<MAX_KEY;index++){
"ijpqI if(hCallWnd[index]==0){
{u !Q=D$3 hCallWnd[index]=hWnd;
:r4]8X- HotKey[index]=cKey;
3[q&%Z. HotKeyMask[index]=cMask;
0cYd6u@ bAdded=TRUE;
s*'L^>iZ KeyCount++;
~kDR9s7 break;
'8%pEl^ }
+Dvdv<+ }
2Y~UeJ_\Lq return bAdded;
TtZZjeg+V }
TcB^Sctf -Iq
W@|N BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
~bm
VpoI {
_(J;!, BOOL bRemoved=FALSE;
T,'{0q for(int index=0;index<MAX_KEY;index++){
GCrIaZ if(hCallWnd[index]==hWnd){
1zo0/<dk if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
3C:!\R hCallWnd[index]=NULL;
{?2jvv HotKey[index]=0;
N=2BrKb)o HotKeyMask[index]=0;
rw CFt6;v bRemoved=TRUE;
j[E8C$lW KeyCount--;
^pI&f{q break;
i4sd29v }
Tbf@qid e }
8(AI|"A"- }
^oZz,q
return bRemoved;
}Iyr u3M][ }
j@w+>h 3HtLD5%Q void VerifyWindow()
?(C(9vO {
ioIOyj for(int i=0;i<MAX_KEY;i++){
B: '}SA{ if(hCallWnd
!=NULL){ Sf_q;Ws
if(!IsWindow(hCallWnd)){ 0LX"<~3j
hCallWnd=NULL; *HT)Au"5
HotKey=0; ?nVwT[
HotKeyMask=0; Vki'pAN
KeyCount--; 5,Q3#f~!
} <V> [H7
} iTX:*$~I
} 1\'?.
} R1!F mZW8
C]X:@^Hy
BOOL CHookApp::InitInstance() "7w~0?}
{ .,-,@ZK
AFX_MANAGE_STATE(AfxGetStaticModuleState()); .2K4<UOAbm
hins=AfxGetInstanceHandle(); a'NxsByG]s
InitHotkey(); \BRxdK'
return CWinApp::InitInstance(); '7'*+sgi$
} 96V@+I
ym\AVRO{
int CHookApp::ExitInstance() E1|> O
{ 5g x9W\a ?
VerifyWindow(); 98c##NV(7|
UnInit(); knX*fp
return CWinApp::ExitInstance(); Ffvv8x
} 8vk*",
fX:)mLnO/
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file mYU7b8x_
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) v?BVUH>#9
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ J
8!D."'Q0
#if _MSC_VER > 1000 zRO-oOJ
#pragma once A-=B#U F
#endif // _MSC_VER > 1000 `.MY"g9
] "ZL<?3g
class CCaptureDlg : public CDialog Z.4 vKO[<
{ S.: m$s
// Construction a{4Wg:
public: 9s#Q[\B!
BOOL bTray; ^#6"d+lp
BOOL bRegistered; AZj`o
BOOL RegisterHotkey(); d9j+==S
<
UCHAR cKey; J|O=w(
UCHAR cMask; -\6";_Y
void DeleteIcon(); |UudP?E
void AddIcon(); $0kuR!U.N
UINT nCount; [N35.O6P6u
void SaveBmp(); 5s5GBJ?
CCaptureDlg(CWnd* pParent = NULL); // standard constructor 5l(8{,NDt
// Dialog Data X0QY:?
//{{AFX_DATA(CCaptureDlg) !!{!T;)l
enum { IDD = IDD_CAPTURE_DIALOG }; _f"HUKGN
CComboBox m_Key; /~8<;N>,+
BOOL m_bControl; %^`b)
BOOL m_bAlt; ^~p^N <
BOOL m_bShift; {6y@;Fd
CString m_Path; @;6I94Bp
CString m_Number; #5Q?Q~E@
//}}AFX_DATA "M-zBBY ]
// ClassWizard generated virtual function overrides Hm>7|!
//{{AFX_VIRTUAL(CCaptureDlg) mJ'Q9x"
public: &J]|pf3m
virtual BOOL PreTranslateMessage(MSG* pMsg); 46yq F
protected: [Iwb7a0p
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support m
L#%H(
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); lmsO
6=I4F
//}}AFX_VIRTUAL 35;UE2d)<
// Implementation 8C[W;&Y=
protected: &N