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:
b7$?'neH/.
u*M*WpY 一、实现方法
f /jN $p Gqs8$[o 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:
. "R
2^` W46sKD;\^W #pragma data_seg("shareddata")
rg`"m HHOOK hHook =NULL; //钩子句柄
R\<^A~(Gl UINT nHookCount =0; //挂接的程序数目
k: {$M yK static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
M! s&<Bi static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
lY~xoHT;[ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
I=1tf;Bsi static int KeyCount =0;
AOTI&v static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
Ei#"r\q j_ #pragma data_seg()
8Hhe&B e0 D;]
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。
NmeTp?)m A >x{\ 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:
}, ]W/ AIE)q]'Q BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
QoqdPk#1 cKey,UCHAR cMask)
htaB!Q?V {
0q/g:"|j BOOL bAdded=FALSE;
,xGlWH wrY for(int index=0;index<MAX_KEY;index++){
P6X 4m(t if(hCallWnd[index]==0){
NE(6`Wq` hCallWnd[index]=hWnd;
4'{j'kuv HotKey[index]=cKey;
$tb$gO HotKeyMask[index]=cMask;
bC&_OU: bAdded=TRUE;
_+UD>u{ KeyCount++;
MPT[f break;
X1+Wb9P }
-i58FJ`B }
Tj>~#~ return bAdded;
$N+azal+y }
>%7iL#3% //删除热键
t?/#:J*_7 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
!D1F4v[c= {
?^yZVmAo] BOOL bRemoved=FALSE;
N%`ikdaTd for(int index=0;index<MAX_KEY;index++){
*u-TNg if(hCallWnd[index]==hWnd){
yXDf;`J if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
2lGq6Au: hCallWnd[index]=NULL;
JK_sl>v.7 HotKey[index]=0;
zRB1V99k HotKeyMask[index]=0;
bJ9>,,D bRemoved=TRUE;
f$P pFSY4 KeyCount--;
g6N{Z e Wg break;
vXyaOZ }
A }dl@ }
fx9c1h9s }
{dA#r>z\1 return bRemoved;
qwnC{ }
9#1lxT4% cP(/+
/9 BM:je(*p DLL中的钩子函数如下:
o\2#o5# Fm*O&6W\@A LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
s7=]!7QGS! {
-FJ5N}R BOOL bProcessed=FALSE;
65MR(+3 if(HC_ACTION==nCode)
{+Eq{8m` {
NC0x!tJ#7 if((lParam&0xc0000000)==0xc0000000){// 有键松开
bGDV9su switch(wParam)
x3)qK6,\ {
hMi[MB7~ case VK_MENU:
nE,"3X" MaskBits&=~ALTBIT;
_w(SHWh2 break;
(zUERw\aX case VK_CONTROL:
0Ebs-kP MaskBits&=~CTRLBIT;
VN*^pAzlF break;
#SQFI;zj case VK_SHIFT:
GCc@
:*4[ MaskBits&=~SHIFTBIT;
w(s"r p} break;
eRD s?n3F default: //judge the key and send message
Nmp1[/{J break;
.4U::j} }
#VD[\# for(int index=0;index<MAX_KEY;index++){
DUa`8cE} if(hCallWnd[index]==NULL)
KbSIKj continue;
]_j{b)t if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
j5tA!o {
5&6S["lt SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
kIM* K%L} bProcessed=TRUE;
7Ij FSN> }
EpS"NQEe }
YwEXTy>0 }
)x#^fN~ 7` else if((lParam&0xc000ffff)==1){ //有键按下
Zs)HzOP)9 switch(wParam)
kyz_r6 {
5^[V%4y> case VK_MENU:
WG<D+P MaskBits|=ALTBIT;
y1f&+y9e break;
zZseK case VK_CONTROL:
]*Zg(YA MaskBits|=CTRLBIT;
jF{zcYU break;
Z&YW9de@ case VK_SHIFT:
u|APx8?"o MaskBits|=SHIFTBIT;
N}Z"$4 break;
{B uh5U, default: //judge the key and send message
$5|/X&"O)/ break;
D24@lZ`g~ }
YWjw`,EA( for(int index=0;index<MAX_KEY;index++){
$Y7q2 if(hCallWnd[index]==NULL)
< JA5.6<= continue;
Bxak[>/ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
\,lgv {
7>v1w:cC] SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
{dhG SM7 bProcessed=TRUE;
r6QNs1f~. }
#%Uk}5;- }
!3}vl
Y1 }
O0c#-K.f if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
oj[Wzeg% for(int index=0;index<MAX_KEY;index++){
a";(C,:0 if(hCallWnd[index]==NULL)
ma vc$!y continue;
4Rp2 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
h@t&n@8O? SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
u\.7#D> //lParam的意义可看MSDN中WM_KEYDOWN部分
K6{{\r }
o%5^dX&[ }
2t*@P"e! }
"\U$aaF return CallNextHookEx( hHook, nCode, wParam, lParam );
o"J}@nF }
\XhzaM
wSBDJvI 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:
v4DF
#O ZWxq<&Cg BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
rhsSV3iM BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Z@=#ry CFkM}`v0 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:
*dL!)+:d E_MGejm@ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
G(EiDo& {
SZea[~& if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
1|Us"GQ(n {
&AG,]# //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
e@F9'z4 SaveBmp();
m
=
"N4! return FALSE;
f)~urGazS }
;*[nZV> …… //其它处理及默认处理
1Y_Cd }
Yu>VW\Fb 8S "vRR :"#EQq]ct 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。
Yw vXSA C2<!.l 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^Lfz-Z FcB]wz 二、编程步骤
#%rXDGDS M8oI8\6[ 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";
H~^am KW]/u 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
4#{i dd@qk`Zl&A 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;
!U/iY%NE ]g2Y/\)a 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;
]'3e#Cqeh al.~[T-O+ 5、 添加代码,编译运行程序。
y+hC !- S~.:B2=5K 三、程序代码
nb9qVuAGU xv4_q-r[ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
lU`]yL #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
<O>1Y09C/ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
Po#;SG#Ee #if _MSC_VER > 1000
yZE"t[q#O #pragma once
Z_.Eale^ #endif // _MSC_VER > 1000
:,X,!0pWRp #ifndef __AFXWIN_H__
&9g4/c-?$ #error include 'stdafx.h' before including this file for PCH
}SR}ET&z #endif
`L/kw Vl #include "resource.h" // main symbols
X>(? class CHookApp : public CWinApp
N{U``LV {
7@NAky( public:
7aUk?Hf CHookApp();
T0J"Wr>WY // Overrides
M.iR5Uh // ClassWizard generated virtual function overrides
K4b#
y~@ //{{AFX_VIRTUAL(CHookApp)
Dm?>U1{ public:
rV>/:FG virtual BOOL InitInstance();
fgVeB;k| virtual int ExitInstance();
[#S}L(
//}}AFX_VIRTUAL
H|T!}M> //{{AFX_MSG(CHookApp)
I0trHrX9 // NOTE - the ClassWizard will add and remove member functions here.
@-|{qP=Dy // DO NOT EDIT what you see in these blocks of generated code !
+YVnA?r? //}}AFX_MSG
}J"}5O2,b DECLARE_MESSAGE_MAP()
-'*\KA@u };
Z6F>SL LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
r<,W{Va BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
=(Y 1y$ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
n8n(< BOOL InitHotkey();
-`x$a&} BOOL UnInit();
JY8wo 5H #endif
Fsv:SL+5 c+|,qm //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Hg\+:}k&9 #include "stdafx.h"
]V\qX+K #include "hook.h"
$R4[TQY).! #include <windowsx.h>
He^u+N@B #ifdef _DEBUG
=X6WK7^0 #define new DEBUG_NEW
?9hw]Q6r} #undef THIS_FILE
`@eo <6 static char THIS_FILE[] = __FILE__;
Y>LgpO. #endif
E~Eh'>Y(B #define MAX_KEY 100
+ Bk"
khH #define CTRLBIT 0x04
-h+=^, #define ALTBIT 0x02
O)NEt #define SHIFTBIT 0x01
eJFGgJRIvF #pragma data_seg("shareddata")
ij i<+oul HHOOK hHook =NULL;
d5mhk[p7\J UINT nHookCount =0;
'~Uo+<v$w static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
3)ac
static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
Z".mEF-b static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
*vqlY[2Ax static int KeyCount =0;
`oQ)qa_ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
ij&_> #pragma data_seg()
@| kBc.(] HINSTANCE hins;
$Ay
j4|_- void VerifyWindow();
o%_MTCANy BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
9|#YKO\\i //{{AFX_MSG_MAP(CHookApp)
1~/?W^ir // NOTE - the ClassWizard will add and remove mapping macros here.
{a-bew // DO NOT EDIT what you see in these blocks of generated code!
lIPy)25~ //}}AFX_MSG_MAP
Sp8Xka~5*# END_MESSAGE_MAP()
d1$3~Xl] h>V8YJ CHookApp::CHookApp()
~"F83+RDe {
(GB2("p` // TODO: add construction code here,
h&d%#6mB // Place all significant initialization in InitInstance
a-w=LpVM }
Cj^:8 ?% Gu}
`X23 CHookApp theApp;
`|@# ~ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
>Hb>wlYR {
<8#Q5 BOOL bProcessed=FALSE;
s6Ox!)& if(HC_ACTION==nCode)
Zo`Ku+RL2' {
JRQ{Q"`) if((lParam&0xc0000000)==0xc0000000){// Key up
0ant0< switch(wParam)
rF C 6"_ {
O9y4.`a" case VK_MENU:
J-C3k`%O MaskBits&=~ALTBIT;
\7M+0Ul1 break;
"J:~Aa%_ case VK_CONTROL:
Qx{k_ye`
MaskBits&=~CTRLBIT;
$%~-p[)<(P break;
v,z s
dr"d case VK_SHIFT:
%Ci`OhT MaskBits&=~SHIFTBIT;
Z^? 1MJ:` break;
0?kaXD default: //judge the key and send message
wcz|Zy break;
h&Thq52R }
|tL57Wu93 for(int index=0;index<MAX_KEY;index++){
=\CJsS. if(hCallWnd[index]==NULL)
H}G=%j0 continue;
$B6CLWB if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
@pq#? {
*xm(K+j SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
HsrIw bProcessed=TRUE;
c"qaULY }
jSa9UD }
TS0x8,'$q }
X"QIH|qx- else if((lParam&0xc000ffff)==1){ //Key down
D5]4(]k& switch(wParam)
WmU5YZ(mAq {
WXz'H),R case VK_MENU:
;M,u,KH)/ MaskBits|=ALTBIT;
h%'4V<V break;
ShXk\" case VK_CONTROL:
[^wEKRt& MaskBits|=CTRLBIT;
_hP siZY9 break;
E({+2}=1 case VK_SHIFT:
u6&<Bv MaskBits|=SHIFTBIT;
OU)~
02|\ break;
;A^0="x& default: //judge the key and send message
jwsl"zL break;
1 o<l;: }
!:
e(- for(int index=0;index<MAX_KEY;index++)
c)H(w {
QoZ7l]^ if(hCallWnd[index]==NULL)
-dX{ R_* continue;
xs<~[l if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
3#fu;??1. {
7P3PQ%: SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
dD6I @N)X bProcessed=TRUE;
_isqk~ ul }
TMt,\gTd }
Nxk3uF^ }
zJ;K4)"j if(!bProcessed){
HQi57QB for(int index=0;index<MAX_KEY;index++){
>7@kwj-f) if(hCallWnd[index]==NULL)
=+um:*a. continue;
a*4"j2j v if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Lg[v-b=?I SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
QF^ _4Yn }
YTBZklM }
'qD5 }
ogN/zIU+VA return CallNextHookEx( hHook, nCode, wParam, lParam );
cd8ZZ8L }
Qd~M;L O"i gH87e BOOL InitHotkey()
;zy[xg.7 {
|~'D8 g:Ak if(hHook!=NULL){
J?/.|Y]e nHookCount++;
}sTo,F$ return TRUE;
u<8 f;C_ }
s|3@\9\ else
]8,:E ]`O hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
B35zmFX|}N if(hHook!=NULL)
9G8n'jWyY nHookCount++;
_4E .
P return (hHook!=NULL);
W}+f}/&l }
=GO/r;4 BOOL UnInit()
)c9]}:W& {
k<b`v&G if(nHookCount>1){
0,)Ao8 nHookCount--;
Eyw)f> return TRUE;
;K[ G]8 }
-w41Bvz0 BOOL unhooked = UnhookWindowsHookEx(hHook);
u3{gX{so if(unhooked==TRUE){
Y-(),k_Q: nHookCount=0;
(s?`*i:2 hHook=NULL;
EZvB#cuL- }
] iKFEd return unhooked;
BKoc;20; }
e@k`C{{C]o F|._'i+B! BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
gcImk0NIY {
(W~jr-O^ BOOL bAdded=FALSE;
W#cr9"'Ta for(int index=0;index<MAX_KEY;index++){
`Pj7O/!)#! if(hCallWnd[index]==0){
6T%5vg_};' hCallWnd[index]=hWnd;
Y.$InQ gL HotKey[index]=cKey;
J"w!Q\_ HotKeyMask[index]=cMask;
]h (TZu bAdded=TRUE;
u7|{~D&f KeyCount++;
e2#"o{+@ break;
wv,,#P }
XQEGMaZ }
|xI\)VE^ return bAdded;
OCy\aCp }
bH7[6#y$ 33d86H%; BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
mT57NP {
iQ=
%iou BOOL bRemoved=FALSE;
hjiU{@q for(int index=0;index<MAX_KEY;index++){
oOk.Fq if(hCallWnd[index]==hWnd){
B`Q.<Lqu if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
'8~cf hCallWnd[index]=NULL;
fgFBOpG%Gq HotKey[index]=0;
'"}|'J HotKeyMask[index]=0;
< 4DWH bRemoved=TRUE;
Zl]Zy}p* + KeyCount--;
w>I>9O}(` break;
]pLQ;7f7D }
cmDskQ: }
E-,74B&H }
]d"4G7mu`l return bRemoved;
H[o'j@0 }
&]~z-0`$! }Gpw2 void VerifyWindow()
,x5`5mT3 {
sr\l z}JW for(int i=0;i<MAX_KEY;i++){
STgl{# if(hCallWnd
!=NULL){
?{#P.2
if(!IsWindow(hCallWnd)){ 6y)xMX
hCallWnd=NULL; %hU8ycI*h
HotKey=0; 7BCCQsz<
HotKeyMask=0; /'1UfjW>
KeyCount--; TX{DZ#
} }~lF Rf
} OVO0Emv
} [KkLpZG
} k/nOz*
{! RW*B
BOOL CHookApp::InitInstance() s-r$%9o5
{ Ah)OyO6
AFX_MANAGE_STATE(AfxGetStaticModuleState()); *iF>}yh e
hins=AfxGetInstanceHandle(); 6w K=
InitHotkey(); -tT{h4
return CWinApp::InitInstance(); ,=lMtW
} ^DHFP-G?e
rtDm<aUh
int CHookApp::ExitInstance() p}.P^`~j
{ IS7g{:}=p
VerifyWindow(); DLE|ctzj[7
UnInit(); Kp"mV=RG2T
return CWinApp::ExitInstance(); zMX7 #,
} !TY4C`/
\s;]Tg
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file ,[+
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) P0$ q{ j
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ u;DF$
#if _MSC_VER > 1000 Y',s|M1})\
#pragma once UuxWP\~2
#endif // _MSC_VER > 1000 TQK>w'L
b@N|sXt&C
class CCaptureDlg : public CDialog !-r@_tn|
{ mLD0Lu_Ob3
// Construction zsI0Q47\
public: :c,\8n
BOOL bTray; Rs)tf|`/
BOOL bRegistered; xZFha=#
BOOL RegisterHotkey(); BZ1@?3
UCHAR cKey; r6]r+!63"
UCHAR cMask; '#t"^E2$
void DeleteIcon(); cl2@p@av
void AddIcon(); !.L%kw7z
UINT nCount; p<'mc|hGq
void SaveBmp(); g=pz&cz;>\
CCaptureDlg(CWnd* pParent = NULL); // standard constructor tjOfekU
// Dialog Data 8_f0P8R!y
//{{AFX_DATA(CCaptureDlg) mT@UQCG
enum { IDD = IDD_CAPTURE_DIALOG }; @Th.=
CComboBox m_Key; '2z o
BOOL m_bControl; dk({J
BOOL m_bAlt; ^`YSl*:
BOOL m_bShift; r0QjCFSF=
CString m_Path; FqsG#6|x
CString m_Number; 3z:
rUhA
//}}AFX_DATA X=(8t2
// ClassWizard generated virtual function overrides Pf)<