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:
!8OgaMngzF
G-eSHv 一、实现方法
*I9O+/, Ri;_
8v[H| 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:
M3Oqto<8" *=(vIm[KL #pragma data_seg("shareddata")
,yH\nqEz HHOOK hHook =NULL; //钩子句柄
'T(@5%Db UINT nHookCount =0; //挂接的程序数目
!Z<=PdI1Ys static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
i6 )HC static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
yoG*c%3V? static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
4}F~h static int KeyCount =0;
yZkS
static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
S pk8u4 #pragma data_seg()
xq<X:\O cV:Ak~PKl 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。
|&U{
z? MIdViS.g 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:
~}RfepM ^]MLEr!S BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
~DP_1V? cKey,UCHAR cMask)
ZY=a[K {
fs0EbVDF BOOL bAdded=FALSE;
vX|5*T`( for(int index=0;index<MAX_KEY;index++){
\gR%PN if(hCallWnd[index]==0){
v"-K-AQjB hCallWnd[index]=hWnd;
<h%I-e6 HotKey[index]=cKey;
0t7vg#v| HotKeyMask[index]=cMask;
p} {H%L bAdded=TRUE;
f"SK3hI$p KeyCount++;
9PdD =9HH break;
ziC%Q8 }
.zv BV_I }
8p_6RvG return bAdded;
9J$-E4G.M }
+
f,Kt9Cy //删除热键
kxmc2RH>nB BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
n+ S&[Y {
`#"xgOSP> BOOL bRemoved=FALSE;
ZdgzPs" for(int index=0;index<MAX_KEY;index++){
xSq{pxX if(hCallWnd[index]==hWnd){
Z): Nd9 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
'^M.;Giz hCallWnd[index]=NULL;
g
cb6*@u! HotKey[index]=0;
tE,&
G-jU HotKeyMask[index]=0;
EYA=fU bRemoved=TRUE;
'}$$0S.DC KeyCount--;
yt<h!k$ _P break;
+`tk LvM }
Q)im2o@z }
p0hE`! }
bE?X?[K return bRemoved;
&O#,"u/q` }
|#yH,f .FG%QF F~ <QD[hO^/ DLL中的钩子函数如下:
JJK-+a6cX Z@}qL1 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
bvS6xU-
J {
?AK`M #M BOOL bProcessed=FALSE;
J4u>77I if(HC_ACTION==nCode)
[0vqm:P {
O L 9(~p if((lParam&0xc0000000)==0xc0000000){// 有键松开
" =6kH, switch(wParam)
nJ h)iQu {
Whe-()pG{ case VK_MENU:
9g]%}+D MaskBits&=~ALTBIT;
<Xw\:5
F<7 break;
QJ!2Vw4K case VK_CONTROL:
FLXn%/ MaskBits&=~CTRLBIT;
&x7iEbRs break;
F^81?Fi. case VK_SHIFT:
OrwVRqW-z MaskBits&=~SHIFTBIT;
nc6PSj X break;
8OiCldw:HN default: //judge the key and send message
Jv} &8D break;
51Vqbtj^ }
"6
~5RCZ for(int index=0;index<MAX_KEY;index++){
-iKoQkHt if(hCallWnd[index]==NULL)
_s*p$/V\ continue;
.><-XJ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
S=\cF,Zs {
D -d SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
x#gZC1$Y bProcessed=TRUE;
fUr%@&~l^ }
<@P. 'rE }
LosRjvQ: }
n'0r
( else if((lParam&0xc000ffff)==1){ //有键按下
'6;
{DX switch(wParam)
TD%&9$F {
%uCsCl case VK_MENU:
|Z)}-'QUJ MaskBits|=ALTBIT;
] E:NmBN< break;
@dx8 {oQ case VK_CONTROL:
U$Z<lx2P MaskBits|=CTRLBIT;
7Mk>`4D'c break;
#ID
fJ2 case VK_SHIFT:
) J.xQ}g MaskBits|=SHIFTBIT;
|1zfXG,R break;
FPH2dN default: //judge the key and send message
p]ujip break;
{xeJO:M3/ }
Q-rG~O9- for(int index=0;index<MAX_KEY;index++){
zw+RDo if(hCallWnd[index]==NULL)
M\-[C!h, continue;
=fJU+N+< if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
&,yF{9$G {
C+g}+ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
~(8f Uob bProcessed=TRUE;
tDRo)z }
d%. |MAE }
E- [Eg }
A*~G[KC3( if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
n_Qua|R for(int index=0;index<MAX_KEY;index++){
X</Sl>[8 if(hCallWnd[index]==NULL)
ul#y'iY] continue;
y0`;
br\X if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
;0Q" [[J SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
,n[<[tkCR //lParam的意义可看MSDN中WM_KEYDOWN部分
x;<0Gg~jB }
NyT%S?@y< }
@HPr;m! }
heL`"Y2'y> return CallNextHookEx( hHook, nCode, wParam, lParam );
IT{c:jo1{` }
FzcXSKHV% 0|.jIix; 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;-Y2* oyr b.lu/ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
QkC*om'/! BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
v0VQ4> @&Z^WN,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:
tH4q*\U _ xTpW LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
qZ'2M.; {
/#
]eVD
if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
wN58uV ' {
ox%j_P9@: //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
AH :uG# SaveBmp();
e4,SR(O> return FALSE;
yQMwt|C4 }
Zp^O1&\SK? …… //其它处理及默认处理
)obgEJ7Y`l }
H`'a|Y fLqjBG]< T.3{}230< 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。
tsL
; wT_ 8["%e#%`$ 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。
^8_yJ=~V n1{[CCee@ 二、编程步骤
ch:rAx &3Yj2Fw 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";
7P<f(@0h$E /'aqQ
K< 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
2.I|8d[ |T@SlNi] 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;
|=*)a2 M:GpyE% 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;
gT0yI;g] NXFi* 5、 添加代码,编译运行程序。
D\b$$z]q 51b%uz 三、程序代码
Y|><Ls6Q :ujpLIjvVG ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
:CW^$Zvq #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
""jW'%wR #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
\cCH/ #if _MSC_VER > 1000
(;;ji!i #pragma once
;b*qunJ3L #endif // _MSC_VER > 1000
]t~.?)Ad+2 #ifndef __AFXWIN_H__
tiE|%jOzt #error include 'stdafx.h' before including this file for PCH
[U/h'A.j #endif
iuGwc086 #include "resource.h" // main symbols
x<M::")5!V class CHookApp : public CWinApp
Fz';H {
aqN{@| public:
\OtreYi CHookApp();
bf0,3~G,P // Overrides
o+&Om~W // ClassWizard generated virtual function overrides
T>'O[=UWh //{{AFX_VIRTUAL(CHookApp)
,wes* public:
#55:qc>m virtual BOOL InitInstance();
4qp|g'uXT virtual int ExitInstance();
Rlk3AWl2u //}}AFX_VIRTUAL
n
5R9<A^ //{{AFX_MSG(CHookApp)
oG1zPspL // NOTE - the ClassWizard will add and remove member functions here.
WM?-BIlT= // DO NOT EDIT what you see in these blocks of generated code !
ioD8- //}}AFX_MSG
9Z!n!o7D DECLARE_MESSAGE_MAP()
;W|NG3_y };
XDJE]2^52? LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
Lm~<BBp. BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
0S$k;q BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
(&Rk#i U
2 BOOL InitHotkey();
NGSts\D'} BOOL UnInit();
d/
^IL*O #endif
\/YRhQ q+\<%$:u //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
2I [zV7 @t #include "stdafx.h"
`
= O #include "hook.h"
wQUl!s7M; #include <windowsx.h>
&&9|;0< #ifdef _DEBUG
NOQ^HEi #define new DEBUG_NEW
,M.}Q ak^ #undef THIS_FILE
o& FOp' static char THIS_FILE[] = __FILE__;
rL1yq|]I #endif
4F|79U # #define MAX_KEY 100
(T#$0RFq #define CTRLBIT 0x04
qisvGHo #define ALTBIT 0x02
(l^7EpNs #define SHIFTBIT 0x01
MGm*({% #pragma data_seg("shareddata")
)1 T2u HHOOK hHook =NULL;
]}!@'+= UINT nHookCount =0;
iVn4eLK^v static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
JkJ
@bh
Eu static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
`^SRg_rH=` static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
|T""v_q static int KeyCount =0;
'JMW.;Lh?X static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
*^|\#UIk
#pragma data_seg()
?d-w#<AiV HINSTANCE hins;
BA:x*(%~ void VerifyWindow();
'c7nh{F BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
x^[,0?y2 //{{AFX_MSG_MAP(CHookApp)
6]b"n'G // NOTE - the ClassWizard will add and remove mapping macros here.
aNEah // DO NOT EDIT what you see in these blocks of generated code!
oL@ -<;zKO //}}AFX_MSG_MAP
71R,R, END_MESSAGE_MAP()
I;t@wbY, %m
|I=P CHookApp::CHookApp()
"iK=
8 {
z9ADF(J?0' // TODO: add construction code here,
X>[i<ei // Place all significant initialization in InitInstance
>N Bc-DX^ }
88osWo6rG Dm}eX:'{ CHookApp theApp;
)*]A$\Oc[ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
.U0Gm_c0 {
OKMdyyO<l BOOL bProcessed=FALSE;
M9W
zsWM if(HC_ACTION==nCode)
G(a5@9F {
2nkA%^tR if((lParam&0xc0000000)==0xc0000000){// Key up
k)n
b<JW|r switch(wParam)
eT".psRiC {
NbU`_^oC case VK_MENU:
zkRAul32| MaskBits&=~ALTBIT;
5j`xSG break;
9S|sTf case VK_CONTROL:
$K^l=X MaskBits&=~CTRLBIT;
1<BKTMBq?{ break;
.kBkYK8*t case VK_SHIFT:
* hs&^G MaskBits&=~SHIFTBIT;
[LnPV2@e break;
uslu-|b!% default: //judge the key and send message
f#!+l1GV break;
U.<j2Kum }
H[~ D]RG}' for(int index=0;index<MAX_KEY;index++){
d-~V. if(hCallWnd[index]==NULL)
S1|u@d' continue;
2o?j{K if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
U80=f2 {
,j*9 ) SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
1VgGF^cYR bProcessed=TRUE;
WEj{2+ }
J 4gtm"2) }
xQFY/Z }
{ ^dq7! else if((lParam&0xc000ffff)==1){ //Key down
U4!KO;Jc switch(wParam)
xfb .Z( {
>.Gmu case VK_MENU:
uBRlvNJ MaskBits|=ALTBIT;
_c>ww<*3 break;
+LRKS case VK_CONTROL:
be8T<F MaskBits|=CTRLBIT;
0/su` break;
dC({B3#e{ case VK_SHIFT:
qf x*a88 MaskBits|=SHIFTBIT;
sGu.G break;
PGP#$JC default: //judge the key and send message
O6G\0o break;
KHAc!4lA }
K
";Et for(int index=0;index<MAX_KEY;index++)
;g!rc#z2g {
Q-oDmjU if(hCallWnd[index]==NULL)
aoey
5hts continue;
GmB&TDm if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
,&UKsrs_ {
UOZ+&DL,L SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
EQ$k^Y8 " bProcessed=TRUE;
R0RxcBtG }
]<^2B?} }
zQyI4RHG[ }
hBX*02p if(!bProcessed){
PMytk`<`zw for(int index=0;index<MAX_KEY;index++){
^K<3_D>1> if(hCallWnd[index]==NULL)
"/zgh continue;
&+#5gii1i if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Yg8*)u0 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
qLCNANWnd }
9A"s7iJ) }
'SXHq>#gA }
"TA0--6 return CallNextHookEx( hHook, nCode, wParam, lParam );
LaQ7A,] }
h+W$\T) nFQuoU]ux BOOL InitHotkey()
JVIFpN" ` {
L?h?LZnq if(hHook!=NULL){
s0iG|vw nHookCount++;
fxd+0R;f return TRUE;
'[WL8,.Q }
9f!
M1 else
vxmX5. hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
-0^]: if(hHook!=NULL)
=de'Yy:\- nHookCount++;
8ao-]QoMZ return (hHook!=NULL);
XkA] 9,@ }
%R>n5m BOOL UnInit()
1Vu#:6% {
e`n ZiM> if(nHookCount>1){
5GM-*Ak @ nHookCount--;
wyy
1M+ return TRUE;
!h.hJt }
HV~Fe!J_ BOOL unhooked = UnhookWindowsHookEx(hHook);
9O 'j+?(`@ if(unhooked==TRUE){
8oJl ] nHookCount=0;
[#Qf#T%5h hHook=NULL;
uN)c!='I }
o-rX 4=T return unhooked;
bG]0| }
Wq4<9D ?y?9;; BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
&3t973= {
H7Q$k4\l BOOL bAdded=FALSE;
/9pxEidVAS for(int index=0;index<MAX_KEY;index++){
1b%Oi.; if(hCallWnd[index]==0){
(I~ hCallWnd[index]=hWnd;
n[Q(q[ULV HotKey[index]=cKey;
J1G}l5N HotKeyMask[index]=cMask;
5mZ2CDV bAdded=TRUE;
|`o|;A] KeyCount++;
GTR*3,rw break;
(p5q MP]L }
b&P)J|Fe }
JQQ[jl; return bAdded;
,'0#q }
I;w! B$g\;$G BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
-FJ3;fP& {
8m{e,o2. BOOL bRemoved=FALSE;
GURiW42 for(int index=0;index<MAX_KEY;index++){
~]-n%J$q if(hCallWnd[index]==hWnd){
M G$+Blw> if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
U
3<
3 T hCallWnd[index]=NULL;
RB %+|@c HotKey[index]=0;
t1w]L HotKeyMask[index]=0;
WK6,K92 bRemoved=TRUE;
-zFJ)!/? KeyCount--;
6Hnez @d break;
Dz0D ^(;V }
!`e`4y*N }
5!?5S$> }
e6taQz@} return bRemoved;
"B{3q`( }
Onq^|r's& `PbY(6CF void VerifyWindow()
DO(};R%= {
8_}t,BC for(int i=0;i<MAX_KEY;i++){
A;L
]=J if(hCallWnd
!=NULL){ N~,Ipf
if(!IsWindow(hCallWnd)){ O]tR~a
hCallWnd=NULL; )jOa!E"
HotKey=0; 66&uK|
HotKeyMask=0; gL_1~"3KGC
KeyCount--; uP* kvi:e
} RxqNgun@
}
)c4tGT<
} YD[HBF)~j
} :xr^E]
7GO9z<m)
BOOL CHookApp::InitInstance() _|u}^MLO
{ AJ}FHym_ZQ
AFX_MANAGE_STATE(AfxGetStaticModuleState()); ~pZ0B#K
J
hins=AfxGetInstanceHandle(); Yk|6?e{+)
InitHotkey(); +g
g_C'"
return CWinApp::InitInstance(); !CU-5bpu
} DU\ytD`u
c0zcR)=mL
int CHookApp::ExitInstance() (c[u_~ ;
{ TX=894{nGh
VerifyWindow(); _p6r5Y
UnInit(); 5.\p]>|G1
return CWinApp::ExitInstance(); mS'Ad<
} >8"(go+02
ms0V1`
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file +#eol~j9N
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 3JGrJ!x
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ h}a}HabA
#if _MSC_VER > 1000 mFTuqujO
#pragma once "<=4]Z
#endif // _MSC_VER > 1000 59zWB,y(P
a=}1`Q
class CCaptureDlg : public CDialog uLzE'ZmV
{ JPZp*5c6A
// Construction TnN
ythwZ
public: ]R""L<K%HF
BOOL bTray; P*!`AWn
BOOL bRegistered; JH\:9B+:L
BOOL RegisterHotkey(); Hl}lxK,]
UCHAR cKey; :f[ w
UCHAR cMask; eE'P)^KV
void DeleteIcon(); _O}m0c
void AddIcon(); 2"G9?)d9
UINT nCount; {
YQS fk
void SaveBmp(); c[ZrQJ
CCaptureDlg(CWnd* pParent = NULL); // standard constructor [e` |<
// Dialog Data D
\i]gfu8W
//{{AFX_DATA(CCaptureDlg) <q=Zg7zB
enum { IDD = IDD_CAPTURE_DIALOG }; `/[5/%
CComboBox m_Key; d0)]^4HT|y
BOOL m_bControl; ?+.mP]d_
BOOL m_bAlt; #A5X,-4G
BOOL m_bShift; UE^o}Eyg
CString m_Path; =Q<VU/
CString m_Number; aM
$2lR])J
//}}AFX_DATA d3q%[[@
// ClassWizard generated virtual function overrides xmnBG4,f
//{{AFX_VIRTUAL(CCaptureDlg) <<01@Q <