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:
{MYlW0)~
W"!nf 一、实现方法
Oa@X! \ wu
3uu1J 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:
tbOe,-U-@ aty
K^*aX #pragma data_seg("shareddata")
8,kbGlSD HHOOK hHook =NULL; //钩子句柄
GD< Afni UINT nHookCount =0; //挂接的程序数目
%Yd}},X_E static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
QMfYM~o static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
\uanQ|Nu static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
*xLMs(gg static int KeyCount =0;
>Zmpsa+ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
OWq~BZ{ #pragma data_seg()
F ^E(AE \LM'KD pP_ 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。
&6}vvgz L<Lu;KnY6 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:
}3?M0 : X.UIFcK^ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
=20Q!wcu cKey,UCHAR cMask)
Tmw
:w~ {
GXHk{G@TS BOOL bAdded=FALSE;
1/#N{rZ for(int index=0;index<MAX_KEY;index++){
EG9S?
$ if(hCallWnd[index]==0){
3q1O:b^eo hCallWnd[index]=hWnd;
/n"A%6S HotKey[index]=cKey;
Q&F@[k HotKeyMask[index]=cMask;
>StvP=our bAdded=TRUE;
b]Z@zS<8 KeyCount++;
q_oYI3 break;
".w*_1G7U }
]j{S' cz }
3'.OghI return bAdded;
*~:@xMa }
<edAWc+ //删除热键
BO{J{ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
2%@j<yS {
N?pD"re)6 BOOL bRemoved=FALSE;
mIr{Wocx for(int index=0;index<MAX_KEY;index++){
s lPFDBx if(hCallWnd[index]==hWnd){
WVo%'DtF` if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
k|
jCc hCallWnd[index]=NULL;
[C d2L&9 HotKey[index]=0;
,cm2uY HotKeyMask[index]=0;
WQK#&r* bRemoved=TRUE;
RcHyePuF)R KeyCount--;
!'[sV^ds break;
H-rf?R2 }
FS@SC`~( }
vb70~k }
\<PX'mnO return bRemoved;
$*@mxwMQ} }
R=9j+74U v=`VDQWq D(r|sw
DLL中的钩子函数如下:
goHr#@ YTGup]d LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
bMv9f
J {
4XKg3l1 BOOL bProcessed=FALSE;
MWB uMF if(HC_ACTION==nCode)
^#Wf {
@FbzKHdV/ if((lParam&0xc0000000)==0xc0000000){// 有键松开
?]7ITF switch(wParam)
(JM4W
"7' {
`i.f4]r case VK_MENU:
@*c+`5)_ MaskBits&=~ALTBIT;
O&O1O>[p1 break;
Aa1 |{^$:L case VK_CONTROL:
\]r{73C MaskBits&=~CTRLBIT;
N.&K"J break;
G;^iwxzhO case VK_SHIFT:
Y&&Y:+
V MaskBits&=~SHIFTBIT;
2'x_zMV break;
D&oC1 default: //judge the key and send message
e~-Dk .i break;
-({\eL$n }
jV7q)\uu^ for(int index=0;index<MAX_KEY;index++){
f?{Y<M~] if(hCallWnd[index]==NULL)
wIY#TBu continue;
_@@S,(MA if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
D'2O#Rj4q {
v)pdm\P SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
>PYe" bProcessed=TRUE;
Y8AU<M }
f9&D1Gh+w }
/g8yc'{p }
prm else if((lParam&0xc000ffff)==1){ //有键按下
_>aesp% switch(wParam)
f/=0 {
{bNnhW*qOu case VK_MENU:
[XQNgSy?z MaskBits|=ALTBIT;
+(P;4ZOmB break;
w?5b: W, case VK_CONTROL:
G!Uq#l> MaskBits|=CTRLBIT;
W5x]bl# break;
wWm#[f],? case VK_SHIFT:
|MRxm"]A
MaskBits|=SHIFTBIT;
5(F!*6i> break;
Tru`1/ 7I default: //judge the key and send message
2GD%=rP2] break;
Z@h]dU5%a }
t4<#k= for(int index=0;index<MAX_KEY;index++){
i$F)h<OU+ if(hCallWnd[index]==NULL)
%\^x3wP&o\ continue;
c^=:]^ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
QK@z##U {
wHY;Y-(ZT SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
:N[2*.c[ bProcessed=TRUE;
OC[a?#R1 }
0}b8S48|? }
Y#Z&$&n }
:*8@MjZ4 if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
S\f^y8*< for(int index=0;index<MAX_KEY;index++){
Te.hXCFD if(hCallWnd[index]==NULL)
ce;9UBkOg2 continue;
F>}).qx if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
~svu0[Vx SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Pq`4Y
K //lParam的意义可看MSDN中WM_KEYDOWN部分
~fgv7=(! }
foN;Q1?lS }
e;gf??8} }
*JDc1$H0 return CallNextHookEx( hHook, nCode, wParam, lParam );
ilNm\fQ. }
q5`Gl vWgh?h/ot 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:
> Euput\ W6*(Y BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
R
vY`9D BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
;Lu}>.t co12\,aD 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:
;or> Sh7 X~R
qv5@- LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
A8A+ImwO" {
`6M(`*Up if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
*}0Q S@FN {
$4?%Z>' //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
>U}~Hv] SaveBmp();
[6D>2b}:{[ return FALSE;
J^?O]| }
1E-$f …… //其它处理及默认处理
N1SR nJu<f }
!YoKKG~_0 :3G9YjzC} LZ@^ A]U 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。
4@VX%5uy kiECJ@5p 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。
PJ_|=bn H11Wb(6Wu 二、编程步骤
,`wxXU7 `W/6xm(X5; 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";
tF'67,~W
zzxU9m~" 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
WH/a#F %? g]{ 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;
5-g0 2g A/.cNen 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;
aCTVY1 ~q9RZ#g13J 5、 添加代码,编译运行程序。
2<'gX>TW ' ZB%McS 三、程序代码
~ 7k
b4[ j@:LMR> ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
?oF@q :W #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
XYn$yR\dj #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
^hgpeu #if _MSC_VER > 1000
E^qKkl #pragma once
'dg OE #endif // _MSC_VER > 1000
JAn3 #ifndef __AFXWIN_H__
4Pt0^;H&jn #error include 'stdafx.h' before including this file for PCH
^=@%@mR/[C #endif
@3G3l|~> #include "resource.h" // main symbols
yWs/~5[F class CHookApp : public CWinApp
U-Iwda8v {
1k7E[G~G| public:
i.#s'm.9 CHookApp();
z6Hl+nq B // Overrides
\0:l9;^4 // ClassWizard generated virtual function overrides
.FC1:y<aO //{{AFX_VIRTUAL(CHookApp)
5yQgGd) public:
uo%zfi? virtual BOOL InitInstance();
ru U| virtual int ExitInstance();
1wq6E //}}AFX_VIRTUAL
=EG[_i{r //{{AFX_MSG(CHookApp)
O[m+5+ // NOTE - the ClassWizard will add and remove member functions here.
mT9TSW} // DO NOT EDIT what you see in these blocks of generated code !
"kL5HD]TC //}}AFX_MSG
^yfT7050 DECLARE_MESSAGE_MAP()
}b{N[ };
%++q+pa LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
)i?wBxq'MA BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
^o{O5&i] BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
%@IR7v~ BOOL InitHotkey();
/!LfEO BOOL UnInit();
#\"5:.H Oz #endif
U2h?l
`nP >y az //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
<?I~ + #include "stdafx.h"
J4JKAv~3 #include "hook.h"
L-Hl.UV #include <windowsx.h>
:JOF!Q #ifdef _DEBUG
!W6]+ #define new DEBUG_NEW
0h5T&U]${Y #undef THIS_FILE
m*(8I=]q static char THIS_FILE[] = __FILE__;
+`9T?:fu #endif
-Z#A}h #define MAX_KEY 100
T+gqu
&9R #define CTRLBIT 0x04
{%
;tN`{M #define ALTBIT 0x02
[WB8X, #define SHIFTBIT 0x01
6.k2,C4dT< #pragma data_seg("shareddata")
gXF.e.uU HHOOK hHook =NULL;
d-c+KV UINT nHookCount =0;
h<}4mo_$ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
,Z3.Le" static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
JWEqy+,Fjw static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
pE`BB{[@ static int KeyCount =0;
:V >Z|?[*H static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
`" #pragma data_seg()
X)'uTf0 HINSTANCE hins;
<Nkj)`%5iK void VerifyWindow();
g4U%(3,>D BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
cm-!6'` //{{AFX_MSG_MAP(CHookApp)
4Sw)IU~K( // NOTE - the ClassWizard will add and remove mapping macros here.
-l^ u1z // DO NOT EDIT what you see in these blocks of generated code!
SkS
vu} //}}AFX_MSG_MAP
%kyvtt END_MESSAGE_MAP()
Ut0oh $2\OBc= CHookApp::CHookApp()
\QQw1c+ {
/SjA;c!. // TODO: add construction code here,
1*#64Y5F // Place all significant initialization in InitInstance
!hEtUF }
7hQrL+%q8 +1_NB;,e CHookApp theApp;
J](AJkGzK LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
V|DAw[!6N {
L%Me
wU0TZ BOOL bProcessed=FALSE;
)%gigQZ+ if(HC_ACTION==nCode)
F!'y47QD {
6"z:s-V if((lParam&0xc0000000)==0xc0000000){// Key up
e![n$/E3R switch(wParam)
jq%Qc9y {
eqg|bc[i!t case VK_MENU:
gm(`SC?a MaskBits&=~ALTBIT;
HW)> ` break;
7$Jb"s case VK_CONTROL:
]haZ T\ MaskBits&=~CTRLBIT;
]*D=^kA0[ break;
Jzo|$W case VK_SHIFT:
5PqL#Eu`! MaskBits&=~SHIFTBIT;
xhWWl(r`5 break;
9-5H~<}fF default: //judge the key and send message
F8S% \i
break;
"@#^/m) }
JgEPzHgx for(int index=0;index<MAX_KEY;index++){
9rf6,hF if(hCallWnd[index]==NULL)
]MKW5Kq continue;
xk7MMRb if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
p
D-k<8| {
;p)RMRMg SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
qs6r9?KP bProcessed=TRUE;
!{>'jvH }
C8W#$a }
ltK\)L }
zmB6Y
t else if((lParam&0xc000ffff)==1){ //Key down
qr~P$ switch(wParam)
#ue WU {
o<cg9 case VK_MENU:
V"K-aO& MaskBits|=ALTBIT;
H65><38X/ break;
%Ya%R@b} case VK_CONTROL:
M#Kke9%2 MaskBits|=CTRLBIT;
^hiIMqY_{` break;
3dheT}XV?p case VK_SHIFT:
41Ga- 0p MaskBits|=SHIFTBIT;
,a
2(h break;
B>C+qj@ default: //judge the key and send message
/<C}v~r break;
[ICFPY6 }
&rs for(int index=0;index<MAX_KEY;index++)
!:Z
lVIA {
08czP-)OZ if(hCallWnd[index]==NULL)
8L1vtYz continue;
*uW l 804 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
O2{~Q{p {
!$n@- SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
.bYZkO:oy bProcessed=TRUE;
4|U$ON?x }
ty ESDp% }
T3wQ Rn }
e'I/}J if(!bProcessed){
`D-P}hDm! for(int index=0;index<MAX_KEY;index++){
$Z|HFV{ if(hCallWnd[index]==NULL)
A>\5fO continue;
r{cmw`WA/P if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
&u+l`F^Z SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
r{ >`" }
=e)t,YVm }
~%chF/H }
OI^??joQ return CallNextHookEx( hHook, nCode, wParam, lParam );
- f?8O6e }
2t7P| b~V1 yopC
<k BOOL InitHotkey()
R?t_tmKXC! {
&2,3R}B/ if(hHook!=NULL){
#Z. QMWq nHookCount++;
'kOkwGf! return TRUE;
!n7'TM' }
hv0bs8h else
'@/1e\ -y hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
]4ib^R~Z if(hHook!=NULL)
+0ALO%G;G" nHookCount++;
#My14u return (hHook!=NULL);
WKAG)4 }
|*/-~5" BOOL UnInit()
iE EP~ {
`w&?SXFO8 if(nHookCount>1){
C$0rl74Wi nHookCount--;
RNF%i~nhO return TRUE;
GbC@ | }
Gf
+>AjU' BOOL unhooked = UnhookWindowsHookEx(hHook);
c,^W/:CQAB if(unhooked==TRUE){
)&DsRA7v nHookCount=0;
kQ]4Bo hHook=NULL;
]=o1to- }
!gJTKQX4 return unhooked;
YqmsL< }
1N_T/I8_F .i {yW BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
6j8\3H~ {
25f[s.pv8 BOOL bAdded=FALSE;
R4X9g\KpAt for(int index=0;index<MAX_KEY;index++){
#zv&h`gY if(hCallWnd[index]==0){
2D(sA hCallWnd[index]=hWnd;
rd>>=~vx=/ HotKey[index]=cKey;
{Q>4zepN! HotKeyMask[index]=cMask;
|$;4/cKfy bAdded=TRUE;
yEMM@5W)8 KeyCount++;
oxBTm|j7 break;
CIui9XNU }
] g<$f#S }
NT2XG&$W> return bAdded;
.820~b0 }
3dz{"hV yZ!~m3Q BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Pl!E$
{
ePZAi"k BOOL bRemoved=FALSE;
"Bv V89 for(int index=0;index<MAX_KEY;index++){
}Ml BmD if(hCallWnd[index]==hWnd){
Zn0a)VH%
if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
@{UUB=}9 hCallWnd[index]=NULL;
CzY18-L@EX HotKey[index]=0;
~3-"1E>Rgy HotKeyMask[index]=0;
:ssj7wl : bRemoved=TRUE;
*|j4>W\J KeyCount--;
~%lA!tsek break;
,;hpqu| }
S,C c0)j> }
St(jrZb }
+)bn}L>Rl return bRemoved;
Tt9cX}&& }
*iY:R u Fw1% void VerifyWindow()
WO{7/h</ {
`#w#!@s#@ for(int i=0;i<MAX_KEY;i++){
9D &vxKE if(hCallWnd
!=NULL){ tBfmjxv
if(!IsWindow(hCallWnd)){ z .\r7
hCallWnd=NULL; $=,pQ q
HotKey=0; d>mT+{3
HotKeyMask=0; TDbSK&w :s
KeyCount--; g\q4-
} $j(d`@.DN~
} 0:71Xm
} livKiX`
} ,?Ie!r$6
d(XOZF
BOOL CHookApp::InitInstance() '_V9FWDZ
{ +c!HXX
AFX_MANAGE_STATE(AfxGetStaticModuleState()); %o4v} mzV
hins=AfxGetInstanceHandle(); &]LpGl
InitHotkey(); o~e_M-
return CWinApp::InitInstance(); tFc<f7k
} +TA~RCd
4h_YVG]ur
int CHookApp::ExitInstance() F .Zk};lb
{ szhSI
VerifyWindow(); 64#Ri!RR}
UnInit(); L fcy#3!
return CWinApp::ExitInstance(); ~E((n
} &L5
)v\z
QW,:'\G
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file VD@$y^!H
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 0>BI[x@
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ gED|2%BXb
#if _MSC_VER > 1000 *xpn-hCp<
#pragma once 6nE/8m
#endif // _MSC_VER > 1000 s@iY'11
)D#} /3s
class CCaptureDlg : public CDialog IO9|o!&>
{ qD\9h`a
// Construction a%U#PF6
public: Q:Pp'[ RK
BOOL bTray; Y$"m*0
BOOL bRegistered; D&"lu*"tg
BOOL RegisterHotkey(); wT- <#+L\
UCHAR cKey;
Hcg7u7M{
UCHAR cMask; #_S]\=N(
void DeleteIcon(); 8@LWg d
void AddIcon(); zI,Qc60B
UINT nCount; %Rf9KQ
void SaveBmp(); 1hCU"|VH:
CCaptureDlg(CWnd* pParent = NULL); // standard constructor 5yK#;!:h
// Dialog Data ezL1,GT
//{{AFX_DATA(CCaptureDlg) /bo=,%wJ[
enum { IDD = IDD_CAPTURE_DIALOG }; Z]G#:
CComboBox m_Key; M_UmnqN1C
BOOL m_bControl; :ChXzZ
BOOL m_bAlt; $
-<(geI
BOOL m_bShift; {_*G"A 9
CString m_Path; fU
;H
CString m_Number; R!"|~OO
//}}AFX_DATA 6Y\TVRR
// ClassWizard generated virtual function overrides QgYt(/S
//{{AFX_VIRTUAL(CCaptureDlg) /D;ugc*3
public: 6pS}\aD
virtual BOOL PreTranslateMessage(MSG* pMsg); yv]|Ce@8A
protected: wE=I3E %
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support N2}Y8aR~
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); p.8
//}}AFX_VIRTUAL ohx$;j
// Implementation H<fi,"X^
protected: fUY05OMZ
HICON m_hIcon; |:#Ug
// Generated message map functions c;"e&tW
//{{AFX_MSG(CCaptureDlg) UcB&