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:
i47j lyH
-!e7L>w 一、实现方法
Y32 "N[yw b2C`g]ibQ 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:
,7_4z]jK 5/MKzoB #pragma data_seg("shareddata")
P7.' kX9 HHOOK hHook =NULL; //钩子句柄
i-"
p)2d=# UINT nHookCount =0; //挂接的程序数目
*\G)z|^yx static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
0bS|fMgc static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
:A1: static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
_;
Y` static int KeyCount =0;
Iu[|<Cx static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
lpB3&H8& #pragma data_seg()
%NHkDa!
2]cRXJ7h 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。
NSQp<
m p-GAe,2q 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:
#V,R >0" K/=|8+IDL BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
"Gb1K9A
im cKey,UCHAR cMask)
r^Zg-|gr {
Ztr Cv? BOOL bAdded=FALSE;
_hu")os for(int index=0;index<MAX_KEY;index++){
TZR)C P5 if(hCallWnd[index]==0){
%McE`155 hCallWnd[index]=hWnd;
eW J`$"z HotKey[index]=cKey;
V)(R]BK{ HotKeyMask[index]=cMask;
AlXNg!j;5K bAdded=TRUE;
J aTp}# KeyCount++;
'cix`l|^ break;
kF"@Ngv. }
n+;6=1d7ZW }
9iUr nG* return bAdded;
vw,rF`LjZ }
p Z: F:
//删除热键
9h4({EE2t BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
\%]I{ {
m,UGWR BOOL bRemoved=FALSE;
j>-gO,v, y for(int index=0;index<MAX_KEY;index++){
G s+3e8 if(hCallWnd[index]==hWnd){
H,nec<Jp if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
y*pUlts< hCallWnd[index]=NULL;
W\&8auds HotKey[index]=0;
0j"8@< HotKeyMask[index]=0;
eIRLNxt+v bRemoved=TRUE;
(8.Z..PH KeyCount--;
Qham^ break;
aT>'.*\ ] }
AP77a*@8 }
{M-YHX>*;g }
?HF%(>M return bRemoved;
6KpHnSW }
h3LE>}6D /x_o!<M S4=~`$eP DLL中的钩子函数如下:
)OiT{-m b2b^1{@h;v LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
e/0<[s*#Q {
M`rl!Ci# BOOL bProcessed=FALSE;
91=OF*w if(HC_ACTION==nCode)
TT=b79k {
]E\n9X-{ if((lParam&0xc0000000)==0xc0000000){// 有键松开
; ;L[e]Z switch(wParam)
1
$/%m_t {
Og,$ sH}` case VK_MENU:
3|.um_ MaskBits&=~ALTBIT;
\jOA+FU[ break;
bFe+m1Q_ case VK_CONTROL:
_?OW0x4 MaskBits&=~CTRLBIT;
DxUKUE break;
1pArZzm> case VK_SHIFT:
ZovW0Q)m MaskBits&=~SHIFTBIT;
4"gM<z break;
{} 3${ default: //judge the key and send message
!O `(JSoG break;
;\f gF@ }
yzqVz_Fi*W for(int index=0;index<MAX_KEY;index++){
H&:jcgV*P if(hCallWnd[index]==NULL)
{
^cV lC_ continue;
su*'d:L if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
%Ev4]}2C1 {
!%"8|)CAr SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
87D*-Gw bProcessed=TRUE;
G6T_O }
xuqv6b. }
a)wJT`xu }
,%uo6% else if((lParam&0xc000ffff)==1){ //有键按下
ee yHy"@ switch(wParam)
1oc3$A {
|&RU/ a case VK_MENU:
RhncBKm*M MaskBits|=ALTBIT;
Q_[ 3`jl break;
Y;?{| case VK_CONTROL:
D9
g#Ff6 MaskBits|=CTRLBIT;
_f$^%?^ break;
a!=D [Gz*5 case VK_SHIFT:
BO;6
u^[ MaskBits|=SHIFTBIT;
;7}VBkH break;
Zl^\Q=*s default: //judge the key and send message
etTn_v break;
r>o63Q: }
D)L+7N0D~ for(int index=0;index<MAX_KEY;index++){
DGS $Ukz&T if(hCallWnd[index]==NULL)
vN`klDJgW[ continue;
ibj87K if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
vX/T3WV
{
LDPUD' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
-*1J f& bProcessed=TRUE;
kM,C3x{A }
k?+?v?I
= }
)h7<?@wv& }
bbE!qk;hEP if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
As'=tIro for(int index=0;index<MAX_KEY;index++){
nAv#?1cjz if(hCallWnd[index]==NULL)
5>[u ` continue;
F(>Np2oi6 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
h1de[q) SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
aAD^^l# //lParam的意义可看MSDN中WM_KEYDOWN部分
a<^ v(r }
3LOdj T
J }
)Y"+,$$>Y` }
`sn^ysp return CallNextHookEx( hHook, nCode, wParam, lParam );
"&Y`+ 0S8 }
k>;`FFQU> HiZ*+T.B 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'=x|K#xj *\
R ]NV BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
X%
t1T4 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
IG2r#N|C# F3On?x) 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:
Te"ioU?. k\5c|Wq|g LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
~%<X0s| {
La`N PY_:> if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
"~sW"n(F_ {
>*35C`^ //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
(A9Fhun SaveBmp();
0X6YdW _2X return FALSE;
+^60T$ }
TM%|'^) …… //其它处理及默认处理
OP[@k }
)_YX DU 9X}10u: ]_f_w9] 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"{{ TcNk hOjk3
k 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。
oB(?_No7 ,Vc6Gwm 二、编程步骤
6'k<+IR ?:Uv[|S#> 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";
+%<(E W+I!q:p4H 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
/:m->
T em%4Ap 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;
igCZ|Ru\ } Y12 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;
-_=nDH ^O?/yV?4c 5、 添加代码,编译运行程序。
)|ju~qbf {'7B6 三、程序代码
$*^7iT4q_t V(H1q`ao9 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
|3('
N#| #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
R`NYEptJ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
*7uH-u"5d #if _MSC_VER > 1000
^pp\bVh2Q] #pragma once
xG~P+n7t5$ #endif // _MSC_VER > 1000
`KZm0d{H #ifndef __AFXWIN_H__
Cjn#00 #error include 'stdafx.h' before including this file for PCH
qU \w= #endif
Vr3Zu{&2 #include "resource.h" // main symbols
is?{MJZ_ class CHookApp : public CWinApp
=x/X:;)> {
=Qy<GeY public:
j*|VctM CHookApp();
{5Q!Y&N.% // Overrides
X]ipI$'+C // ClassWizard generated virtual function overrides
aC]$k'71 //{{AFX_VIRTUAL(CHookApp)
1KU!
tL public:
#|uCgdi virtual BOOL InitInstance();
y6g&Y.:o virtual int ExitInstance();
Akq2 d; //}}AFX_VIRTUAL
jk;j2YNPw //{{AFX_MSG(CHookApp)
7y.kQI?3 // NOTE - the ClassWizard will add and remove member functions here.
W_JlOc!y // DO NOT EDIT what you see in these blocks of generated code !
p?02C#p //}}AFX_MSG
akmkyrz '& DECLARE_MESSAGE_MAP()
D(~U6SR };
D,k6$` LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
f[]dfLS"W BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
GV1pn) 4 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
lt/1f{v[: BOOL InitHotkey();
1y:-N6 BOOL UnInit();
W8G,=d}6 #endif
FUiRTRIYe Pd8![Z3 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
8=!D$t\3 #include "stdafx.h"
0-B5`=yU #include "hook.h"
XgZD%7 #include <windowsx.h>
A[B<~ #ifdef _DEBUG
u2tfF #define new DEBUG_NEW
lqy Qf$t #undef THIS_FILE
y#`tgJ: static char THIS_FILE[] = __FILE__;
v_yw@ #endif
m&d|t>3< #define MAX_KEY 100
`~cqAs}6]Q #define CTRLBIT 0x04
___~D
dq #define ALTBIT 0x02
Mc) }\{J #define SHIFTBIT 0x01
aEB_#1 #pragma data_seg("shareddata")
<;lkUU(WT2 HHOOK hHook =NULL;
[|v][Hwv UINT nHookCount =0;
\P[Y`LYL static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
kBS9tKBWg static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
q9B$"n static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
QL(n} {.% static int KeyCount =0;
r-,%2y? static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
59LG{R2 #pragma data_seg()
~-k9%v` HINSTANCE hins;
)705V|v void VerifyWindow();
<|HV. O/! BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
e+EQ]<M //{{AFX_MSG_MAP(CHookApp)
5=-Q4d // NOTE - the ClassWizard will add and remove mapping macros here.
MxKS4k // DO NOT EDIT what you see in these blocks of generated code!
e1yt9@k, //}}AFX_MSG_MAP
*tA1az-jO END_MESSAGE_MAP()
dRYqr}!%n /WcG{Wdp CHookApp::CHookApp()
poE0{HOU {
7g^]:3f! // TODO: add construction code here,
p%ki>p )E| // Place all significant initialization in InitInstance
q])K,) }
!|(-=2` gb1V~ CHookApp theApp;
/|}EL%a LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
l$KA)xbI {
Da*?x8sSL BOOL bProcessed=FALSE;
hPB9@hT$ if(HC_ACTION==nCode)
h4gXvPS&r {
ic:zsuEm if((lParam&0xc0000000)==0xc0000000){// Key up
M/f<A$xx_ switch(wParam)
AYBns]! {
C[cbbp case VK_MENU:
yX>K/68 MaskBits&=~ALTBIT;
yZY \MB/ break;
gjyYCjF case VK_CONTROL:
k t#fMd$ MaskBits&=~CTRLBIT;
_;S-x break;
/8'NG6"H` case VK_SHIFT:
; nfdGB MaskBits&=~SHIFTBIT;
!/b>sN} break;
|l^uEtG default: //judge the key and send message
^CYl\.Y@ break;
n&4N[Qlv, }
g/d<Zfq<{ for(int index=0;index<MAX_KEY;index++){
UW={[h{.|@ if(hCallWnd[index]==NULL)
QE+g
j8 continue;
&J]K3w1p if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
#P9~}JB3, {
|*xA8&/ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
L<cx:Vz bProcessed=TRUE;
WDYeOtc }
yWc$>ne[L }
tKuwpT1Qc }
"S]0 else if((lParam&0xc000ffff)==1){ //Key down
9<?M8_ switch(wParam)
oSKXt}sh {
2RX;Ob_ case VK_MENU:
}-{H Y MaskBits|=ALTBIT;
8NJqV+jn)t break;
oCv.Ln1;Z case VK_CONTROL:
t>RY7C;PuS MaskBits|=CTRLBIT;
C==hox7b break;
M<Ncb case VK_SHIFT:
QVT5}OzMt MaskBits|=SHIFTBIT;
@i_FTN break;
?zMHP#i default: //judge the key and send message
<NY^M! break;
H2 {+) }
u~:y\/Y6 for(int index=0;index<MAX_KEY;index++)
x_}:D *aI {
Mj3A5;# if(hCallWnd[index]==NULL)
h2A <" w continue;
qA7>vi% if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
k"%~"9 {
2zA4vZkbcw SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
:pY/-Cgv bProcessed=TRUE;
fw~Bza\e }
Q8tL[>Xt }
B]wk+8SMY. }
|s(FLF - if(!bProcessed){
8'[7
)I= for(int index=0;index<MAX_KEY;index++){
&{hL&BLr if(hCallWnd[index]==NULL)
Fyx|z'4b continue;
=o(5_S.u; if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
SM#]H-3 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
gfd"v }
gCS<iBT(7 }
'F3f+YD }
nNV'O(x} return CallNextHookEx( hHook, nCode, wParam, lParam );
?
(Oy\ }
(`>+zT5aH }'V5/>m[ BOOL InitHotkey()
6vo;!V6 {
}OR@~V{Gj if(hHook!=NULL){
@})|Z}~ nHookCount++;
E0=)HTtS return TRUE;
,eW%{[g( }
^ogt+6c else
GW@;}m( hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
iN\4gQ! if(hHook!=NULL)
zkrM/ @p# nHookCount++;
4r#= * return (hHook!=NULL);
hbDXo: }
8I?Wt
W BOOL UnInit()
x,+{9 {
|bHelD| if(nHookCount>1){
-UEZ#Q nHookCount--;
TDKki(o=~ return TRUE;
BLdvyVFx }
]i)c{y BOOL unhooked = UnhookWindowsHookEx(hHook);
%6,SKg p if(unhooked==TRUE){
&X ):4 nHookCount=0;
-H@:* hHook=NULL;
B\=8_z }
P>C~
i:4n return unhooked;
.Iw AK/QS }
drP=A~?&: X*XZb F"= BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
KnQ*vM*VM {
Jy:Qlx` BOOL bAdded=FALSE;
dJoaCf`w for(int index=0;index<MAX_KEY;index++){
~s*)f.l if(hCallWnd[index]==0){
)h4f\0 hCallWnd[index]=hWnd;
5"@*?X K^ HotKey[index]=cKey;
0B/,/KX HotKeyMask[index]=cMask;
[< ?s?Ci bAdded=TRUE;
;>yxNGV` KeyCount++;
<n];mfh1 break;
HxV=F66"
}
->-KCd1b }
~{g [<Qi return bAdded;
ay
;S4c/_ }
gMmaK0uhS eS\Vib BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
x b~yM%*c {
cWsNr'MS* BOOL bRemoved=FALSE;
|(E
FY\ for(int index=0;index<MAX_KEY;index++){
rC% *$g $ if(hCallWnd[index]==hWnd){
ci.+pF if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
$?Hu#Kn,( hCallWnd[index]=NULL;
2B[X,rL.pX HotKey[index]=0;
T|e u HotKeyMask[index]=0;
9igiZmM bRemoved=TRUE;
4y?n
[/M/ KeyCount--;
u(>^3PJ+ break;
L-WT]&n_ }
)._; ~z! }
Fn;SF4KOm }
q4:o#K# return bRemoved;
_[c0)2h }
=JEv,ZGT3 6:[dj*KGmT void VerifyWindow()
VU(v3^1" {
fI}to&qk for(int i=0;i<MAX_KEY;i++){
-`kW&I0 if(hCallWnd
!=NULL){ i Dp)FQ$
if(!IsWindow(hCallWnd)){ D9=KXo^
hCallWnd=NULL; JN-y)L/>
HotKey=0; (AaoCa[
HotKeyMask=0; RQ'9m^
KeyCount--; {yHCXFWlS
} XK3tgaH
} XkE`U5.
} JV^=v@Z3
} \5:i;AE
5h=}j
BOOL CHookApp::InitInstance() %~H-)_d20
{ ?}tFN_X"
AFX_MANAGE_STATE(AfxGetStaticModuleState()); *=/ { HvJ
hins=AfxGetInstanceHandle(); +US!YU
InitHotkey(); |&+o^
return CWinApp::InitInstance(); W.f/pu
} 9}!qR|l3nR
!*dI|k
int CHookApp::ExitInstance() (&F}/s gbi
{ XH 4
VerifyWindow(); 0WW2i{7`U
UnInit(); A5I)^B<(
return CWinApp::ExitInstance(); eCU:Q
} h6D<go-b56
ArI2wM/v
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file a
od-3"7[
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 45@ I *`
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ w7.V6S$Ga
#if _MSC_VER > 1000 X"|['t
#pragma once ,Bi.1
%$
#endif // _MSC_VER > 1000 !21FR*
%op**@4/t\
class CCaptureDlg : public CDialog K( c\wr\6
{ abmYA#
// Construction |PCm01NU!
public: VX0 %a@ur
BOOL bTray; #?U}&Bd
BOOL bRegistered; pSH=%u>
BOOL RegisterHotkey(); hB]Np1('
UCHAR cKey; .GPT!lDc
UCHAR cMask; YNyk1cE
void DeleteIcon(); Uou1mZz/
void AddIcon(); hP%M?MKC
UINT nCount; *MFIV02[N
void SaveBmp(); 7?!d^$B
CCaptureDlg(CWnd* pParent = NULL); // standard constructor ed{ -/l~j
// Dialog Data fM :]&
//{{AFX_DATA(CCaptureDlg) T?CdZc.
enum { IDD = IDD_CAPTURE_DIALOG }; F`9xVnK=
CComboBox m_Key; lBLARz&c#
BOOL m_bControl; 'A=^Se`=
BOOL m_bAlt; zOAd~E
BOOL m_bShift; %8 B}Cb&2c
CString m_Path; A7Cm5>Y_S
CString m_Number; kYP#SH/
//}}AFX_DATA CAig]=2'
// ClassWizard generated virtual function overrides Wq D4YGN
//{{AFX_VIRTUAL(CCaptureDlg) 2G& a{
public: 9rA0lqr]5
virtual BOOL PreTranslateMessage(MSG* pMsg); "+R+6<