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:
ANNfL9:Jy
PK#; \Zw 一、实现方法
_7(>0GY aHosu=NK 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:
Ctpr. #%4-zNS #pragma data_seg("shareddata")
#{)=%5=c HHOOK hHook =NULL; //钩子句柄
=}Np0UP UINT nHookCount =0; //挂接的程序数目
2f8fA'|O static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
`B{N3Kxbp static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
wf!?'* static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
^zv0hGk 2 static int KeyCount =0;
?lJm}0> static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
KLW#+vZ #pragma data_seg()
7q>WO HhN;&67~Z 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。
.'md `@t p/|]])2 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:
ozZW7dveU %oasIiO BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
'u }|~u?m cKey,UCHAR cMask)
SomA`y+ERn {
F V8K_xj BOOL bAdded=FALSE;
sW[8f
Z71 for(int index=0;index<MAX_KEY;index++){
*{t{/^'y if(hCallWnd[index]==0){
=v-BzF15 hCallWnd[index]=hWnd;
m}\G.$ h4 HotKey[index]=cKey;
p2N;- HotKeyMask[index]=cMask;
D2 o,K&V bAdded=TRUE;
3fJGJW!zu KeyCount++;
f>k<I[C< break;
d'~
k f# }
pqmS
w }
5;wA7@ return bAdded;
3okh'P%+ }
#9Z\jW6b //删除热键
gF(aYuk BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
MA\"JAP/ {
.CI {g2 BOOL bRemoved=FALSE;
q@K;u[zFK for(int index=0;index<MAX_KEY;index++){
rPVz!(;k if(hCallWnd[index]==hWnd){
p\]Mf#B if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
;Wa4d`K hCallWnd[index]=NULL;
aZt5/|B HotKey[index]=0;
VG*Tdaua~ HotKeyMask[index]=0;
C~PrIM? bRemoved=TRUE;
}D_h*9 KeyCount--;
~|e?@3_G break;
3+mC96wN }
OOy]:t4 / }
~Zbr7zVn }
J0BA@jH5 return bRemoved;
%$/t`'&o- }
QiB^U^f q:4 51 C 6/^$SWd2 DLL中的钩子函数如下:
iaAVGgA9+ 0e1W& LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
8?ldD {
Mg?^ 5`* BOOL bProcessed=FALSE;
cn&\q.!fh if(HC_ACTION==nCode)
">vxYi {
!+tz<9BBY if((lParam&0xc0000000)==0xc0000000){// 有键松开
4.|-?qG switch(wParam)
j4j %r( {
QXZjsa_| case VK_MENU:
T#'+w@Q9{9 MaskBits&=~ALTBIT;
FB{4& ; break;
9%e&Z'l case VK_CONTROL:
>S4klW=*I MaskBits&=~CTRLBIT;
%Q:i6 ~ break;
LaL.C^K case VK_SHIFT:
o7"2"(
=> MaskBits&=~SHIFTBIT;
[MfKBlA break;
DC4,*a~ default: //judge the key and send message
?4%'6R break;
PjriAlxD }
ea-NqdGs;m for(int index=0;index<MAX_KEY;index++){
.v<c_~y if(hCallWnd[index]==NULL)
nQ4 s continue;
@!z9.o; if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
VT1Nd {
M`!\$D SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
x&qC~F*QR% bProcessed=TRUE;
Jolr"F? }
rYUhGmg` }
^:g8mt }
U$o\?4 else if((lParam&0xc000ffff)==1){ //有键按下
%/KN-* switch(wParam)
<Z%iP{ {
AfmGA9 case VK_MENU:
/ sI0{ MaskBits|=ALTBIT;
dIiQ^M break;
J
[}8&sn case VK_CONTROL:
MNURY A= MaskBits|=CTRLBIT;
k,o|"9H break;
jEr/*kv case VK_SHIFT:
e%#(:L MaskBits|=SHIFTBIT;
6x%uWZa' break;
u4QPO:,a4 default: //judge the key and send message
0Lcd@3XL break;
vJ96qX }
|0 #J=am for(int index=0;index<MAX_KEY;index++){
kfaRN^ if(hCallWnd[index]==NULL)
o~7~S continue;
(=:9pbP if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
ax{+7 k {
2\h]*x%: SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
~nk{\ rWO bProcessed=TRUE;
.>z)6S_G }
)-$Od2u2c }
9-)D"ZhLe }
[4uTp[U!r if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
<4,hrx&. for(int index=0;index<MAX_KEY;index++){
,4$ZB(\ if(hCallWnd[index]==NULL)
9?c0cwP? continue;
r )8[LN- if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
`I+G7KK SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
vt0XCUnK //lParam的意义可看MSDN中WM_KEYDOWN部分
{KJ !rT }
6 R}]RuFQ }
W]Z;=-CBr }
HO ,z[6 return CallNextHookEx( hHook, nCode, wParam, lParam );
rUjK1A{V }
SaKaN#C QixEMX4< 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
_@I<H\^ F9rxm BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
+92/0 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
v%O KOrJ 4DY\QvW5 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
sE87}Lz hKP7p LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
,!U._ic'B {
pyA;%vJn if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
4%L`~J4 wr {
: vN'eL|# //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
o*OYZ/_L SaveBmp();
b#;%TbDF return FALSE;
` #Qlr+X }
!#0Lo->OO …… //其它处理及默认处理
^|yw)N]Q/ }
s=0z%~H
TVVL1wZ 9\9:)q 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
po@=$HK tU2 8l. 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。
/wplP+w2 'TWZ@8h~ 二、编程步骤
xa+=9=<AQ 5U)Ia>p 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";
wZv"tbAWLV '0QrM,B9 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
dg[&5D1Q
Q)eYJP=W 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;
6Y4sv5G $10"lM[ 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
/VFh3n>I2 S?pWxHR] 5、 添加代码,编译运行程序。
olc7&R &'{6_-kh 三、程序代码
=6FA(R|QU 'Fi\Qk'D@ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
jWHv9XtW #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
C3EQzr` #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
#-S%aeB #if _MSC_VER > 1000
ph*?y #pragma once
w|$i<OIi) #endif // _MSC_VER > 1000
fFu+P<?" #ifndef __AFXWIN_H__
R42+^'af #error include 'stdafx.h' before including this file for PCH
*?sdWRbu}l #endif
;a@%FWc #include "resource.h" // main symbols
d/I,` class CHookApp : public CWinApp
iTTUyftHT {
lu~<pfg public:
, y%!s27 CHookApp();
W&E?#=*X // Overrides
t>nx#ErS // ClassWizard generated virtual function overrides
9<qAf` //{{AFX_VIRTUAL(CHookApp)
-'SpSy'_ public:
OV<'v%_& virtual BOOL InitInstance();
Q<4Sd:P`" virtual int ExitInstance();
fuRCM^U( //}}AFX_VIRTUAL
IM-O<T6r[N //{{AFX_MSG(CHookApp)
;2Aqztp // NOTE - the ClassWizard will add and remove member functions here.
#.1+-^TQk // DO NOT EDIT what you see in these blocks of generated code !
{8b6M //}}AFX_MSG
(jj=CLe DECLARE_MESSAGE_MAP()
sfb)iH|sW };
u-v/`F2wN LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
L1P.@hJ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
n*twuB/P 1 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
#0OW0:Q BOOL InitHotkey();
XMt)\r. BOOL UnInit();
5d ?\>dA #endif
N]yh8"7X 44e:K5;]7 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
&y\7pAT\ #include "stdafx.h"
dMn0nc+ #include "hook.h"
9j'(T:Zs #include <windowsx.h>
!vd(WKq #ifdef _DEBUG
b+b]., #define new DEBUG_NEW
-M\ae #undef THIS_FILE
pBo=omQV static char THIS_FILE[] = __FILE__;
Y.>F fL #endif
F3)w('h9c #define MAX_KEY 100
gJ \CT'/ #define CTRLBIT 0x04
ngmHiI W #define ALTBIT 0x02
,3+ #?H #define SHIFTBIT 0x01
UNK}!>HD #pragma data_seg("shareddata")
.7GTL HHOOK hHook =NULL;
.J?cV;:` UINT nHookCount =0;
o03Y w)* static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
P_(QG
6 static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
},r9f MJ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
pi?$h"y7Q static int KeyCount =0;
CEQs}bz static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
EA#{N< #pragma data_seg()
^l;N;5L HINSTANCE hins;
yLpsK[)}\ void VerifyWindow();
sVT:1 kI BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
qYba%g9RN( //{{AFX_MSG_MAP(CHookApp)
&YiUhK // NOTE - the ClassWizard will add and remove mapping macros here.
SM?rss.= // DO NOT EDIT what you see in these blocks of generated code!
c&>S //}}AFX_MSG_MAP
l$1
] END_MESSAGE_MAP()
5/w4[d (:|g"8mQm CHookApp::CHookApp()
QOT|6)Yb {
&/+LY_r'<I // TODO: add construction code here,
V -X*e // Place all significant initialization in InitInstance
\mp2LICQg }
BIQQJLu 7+'&(^c CHookApp theApp;
zCz"[9k LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
HpCTQ\H {
2!kb? BOOL bProcessed=FALSE;
h^ o@=%b if(HC_ACTION==nCode)
h#:_GNuF {
L!| `IK if((lParam&0xc0000000)==0xc0000000){// Key up
Ef)v("'w switch(wParam)
zWO!z= {
S{d]0 case VK_MENU:
NCX`-SLv MaskBits&=~ALTBIT;
ro}WBv break;
Y|X!da/ case VK_CONTROL:
;Q.'u MaskBits&=~CTRLBIT;
Xtk3~@ break;
h/s8".\ case VK_SHIFT:
.]XBJc MaskBits&=~SHIFTBIT;
b )(si/]\ break;
U;w|
=vM default: //judge the key and send message
(fqU73 break;
xwhS[d }
dy"7Wl]hi7 for(int index=0;index<MAX_KEY;index++){
9EFQo^
E if(hCallWnd[index]==NULL)
o;[cApiQ,2 continue;
qu`F,OG if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
e'dx
Y( {
]H-5 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
P*!~Z*" bProcessed=TRUE;
9O4\DRe5c }
|s!<vvp] }
16-1&WuY@ }
Z,_EhEm else if((lParam&0xc000ffff)==1){ //Key down
Y 8Dn&W switch(wParam)
7W.z8>p {
]^>RBegJBO case VK_MENU:
\Dx5= Lh MaskBits|=ALTBIT;
E51'TT9 break;
;659E_y> case VK_CONTROL:
y F;KyY{ MaskBits|=CTRLBIT;
=WEWs4V5A break;
TQL_K8k@_ case VK_SHIFT:
=38c}( MaskBits|=SHIFTBIT;
p!/ *(TT break;
a/Ik^:>m default: //judge the key and send message
Nm{J=` break;
=a$7^d }
ecdM+kP for(int index=0;index<MAX_KEY;index++)
iezY+`x4 {
?mbI6fYv if(hCallWnd[index]==NULL)
*r/o
\pyH continue;
jBr3Ay@< if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
.22}=z {
:G4)edwe SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
"ivSpec.V bProcessed=TRUE;
]N^>>k }
dTVh{~/ }
R^VmNj }
tSX,*cz if(!bProcessed){
Z}`A'#! for(int index=0;index<MAX_KEY;index++){
z{(c-7* if(hCallWnd[index]==NULL)
M?v`C>j continue;
fO{'$?K if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
s*tzU.E( SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
OrRU$5Lo }
-Gj."ks }
$h|8z }
v$~ZT_"(9 return CallNextHookEx( hHook, nCode, wParam, lParam );
)U+Pt98" }
1Q!^%{Y; 2>F`H7W BOOL InitHotkey()
\=
G8 {
#XeEpdE if(hHook!=NULL){
1$v1:6 nHookCount++;
7hAc6M$h; return TRUE;
1#V&'A }
oV;I8;#\J else
f-5}`)`.+ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
yv(\5)XF if(hHook!=NULL)
'/GZ/$a_l nHookCount++;
GmdS~Fhp return (hHook!=NULL);
ia*Bcx_RW+ }
tD+K4
^ BOOL UnInit()
=SK{|fBB {
28,g 'k! if(nHookCount>1){
' p!\[*e nHookCount--;
W@WKdaJ return TRUE;
Ey]P
>J }
i{MzQE+_^ BOOL unhooked = UnhookWindowsHookEx(hHook);
pIgjo>K if(unhooked==TRUE){
`7jdV nHookCount=0;
\w=*:Z hHook=NULL;
qM9> x:V }
+8 }p-<a return unhooked;
(;2]`D [x }
;|D8"D6] ;T|hNsSt BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
s}Q*zy {
2X`5YN; BOOL bAdded=FALSE;
TIVrbO\!o for(int index=0;index<MAX_KEY;index++){
nA.~} if(hCallWnd[index]==0){
q/dja hCallWnd[index]=hWnd;
m<GJ1)%3i HotKey[index]=cKey;
~IS3i'bh HotKeyMask[index]=cMask;
K)nn;j= bAdded=TRUE;
^cI 0d,3= KeyCount++;
Y/`*t(/5 break;
8]A`WDO3 }
9~6~[z }
i3<ZFR return bAdded;
m:C |R-IL }
vx4Jk]h+=L GU]_Z!3 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
!A#(bC {
jB0ED0)wX BOOL bRemoved=FALSE;
t4FaU7 for(int index=0;index<MAX_KEY;index++){
5tcJTz if(hCallWnd[index]==hWnd){
&)F#cVB if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
.WpvDDUK3 hCallWnd[index]=NULL;
11BfJvs: HotKey[index]=0;
oWcBQ| HotKeyMask[index]=0;
;0Mg\~T~' bRemoved=TRUE;
\"=b8x KeyCount--;
k-|b{QZ8!; break;
O_|p{65 }
PJ'.s
}
8BggK6X }
?vocI return bRemoved;
)jm u*D5N }
9p%8VDF= {"@E_{\ void VerifyWindow()
+^V%D!.$@ {
nI<Ab_EB for(int i=0;i<MAX_KEY;i++){
|emZZj if(hCallWnd
!=NULL){ ]?n~?dD{]
if(!IsWindow(hCallWnd)){ j[&C6l+wH
hCallWnd=NULL; =7 ${bp!
HotKey=0; p'YNj3&u
HotKeyMask=0; z]0UW\S/
KeyCount--; F'3-*>]P
} ca?;!~%zA
} x[1(cj
} BZs?tbf
} \"AzT{l!;
zR6^rq*
BOOL CHookApp::InitInstance() ` EgO&;1D)
{ kz?m `~1
AFX_MANAGE_STATE(AfxGetStaticModuleState()); FX:'38-fk
hins=AfxGetInstanceHandle(); X.hVMX2B
InitHotkey(); YMIX|bj6Y
return CWinApp::InitInstance(); mFeoeI,Jv
} U(u$5
V0a)9\x(\
int CHookApp::ExitInstance() *pKj6x
{ d ~3GEK
VerifyWindow(); N
Uq'96{Y
UnInit(); XdGA8%^cY
return CWinApp::ExitInstance(); DgRA\[c
} G8Sx;Xi
k5TPzm=y{
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file X7{ h/^
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) X)k+BJ
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ zx=AT
#if _MSC_VER > 1000 M`gr*p
#pragma once ]q|^?C
#endif // _MSC_VER > 1000 Fc.1)yh.
:}}~ $$&
class CCaptureDlg : public CDialog ~@N0$S
{ RlnJlY/
// Construction .qG*$W2f
public: )1 =|\
BOOL bTray; #vBS7ba
BOOL bRegistered; .m
\y6
BOOL RegisterHotkey(); 3FpS o+
UCHAR cKey; q+}Er*r
UCHAR cMask; BHEZ<K[U
void DeleteIcon(); o7WK"E!pF'
void AddIcon(); k=r)kkO)
UINT nCount; eK'ztqQ
void SaveBmp(); m-)yQM8
CCaptureDlg(CWnd* pParent = NULL); // standard constructor *w_f-YoXp
// Dialog Data O a#m}b
//{{AFX_DATA(CCaptureDlg) Q2 @Ugt$
enum { IDD = IDD_CAPTURE_DIALOG }; Nw|m"VLb
CComboBox m_Key; 4>$weu^
BOOL m_bControl; M}*#{UV2
BOOL m_bAlt; SM@RELA'Lb
BOOL m_bShift; L!V6Rfy
CString m_Path; `1qM Sq
CString m_Number; -|&5aH]
//}}AFX_DATA M~#%
[?iU
// ClassWizard generated virtual function overrides 7n*[r*$
//{{AFX_VIRTUAL(CCaptureDlg) of>"qrdZ
public: RmcQGQ
virtual BOOL PreTranslateMessage(MSG* pMsg); K^fH:pV
protected: L fx$M
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support SFRQpQ06
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); pu9ub.
//}}AFX_VIRTUAL o6~9.~_e
// Implementation gBCO>nJws
protected: ~76qFZe-
HICON m_hIcon; *g;4?_f
// Generated message map functions 0'O*Y
]h+
//{{AFX_MSG(CCaptureDlg) .P>-Fh,_p
virtual BOOL OnInitDialog(); 1xF<c<
afx_msg void OnSysCommand(UINT nID, LPARAM lParam); Z$&