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:
o|$D|E
w OL,L U 一、实现方法
q'D Ts9Bj `[ZswLE 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
J}|X \C~X_/sg #pragma data_seg("shareddata")
)g5?5f; HHOOK hHook =NULL; //钩子句柄
F)3+IuY UINT nHookCount =0; //挂接的程序数目
lyn%r static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
TrI+F+; static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
R'BB- static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
]jT}]9Q$ static int KeyCount =0;
fQ+whGB static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
$4bc! #pragma data_seg()
Hv6h7- )f?I{ 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
!gh8 Qs r$jWjb 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:
R%r
bysP ZmK=8iN9J BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
'g#%> cKey,UCHAR cMask)
)~2\4t4|g {
\JLGw1F BOOL bAdded=FALSE;
Bdo{zv&A for(int index=0;index<MAX_KEY;index++){
y r (g/0 if(hCallWnd[index]==0){
y
oW~ hCallWnd[index]=hWnd;
v,4{:y]p HotKey[index]=cKey;
+C~h( HotKeyMask[index]=cMask;
>Kgw2,y+ bAdded=TRUE;
q,v<:sS9T KeyCount++;
QM,#:m1o break;
{}$9
70y }
:Cq73:1\B }
NuZ2,<~9 return bAdded;
Dfs^W{YA }
=VC18yA //删除热键
z/t|'8f BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
:{u`qi {
+pd,gG?dW BOOL bRemoved=FALSE;
WJ{Iv] }9 for(int index=0;index<MAX_KEY;index++){
3W1Lh~Av if(hCallWnd[index]==hWnd){
fCt|8,-H if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
NcA
`E_3 hCallWnd[index]=NULL;
C% -Tw]T$_ HotKey[index]=0;
@3`5(xwzm HotKeyMask[index]=0;
=rKJJa N bRemoved=TRUE;
b.*LmSX# KeyCount--;
c^}G=Z1@ break;
.*zN@y3 }
^O|fw?, }
y2W+YV* }
0E.N3iU return bRemoved;
0 C4eer+D }
i/:L^SQAq R"ON5,E U[C>Aoze DLL中的钩子函数如下:
WD5J2EePT 7F<{ Qn LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
G
;j1zs {
@*%3+9`yq BOOL bProcessed=FALSE;
?
AfThJc if(HC_ACTION==nCode)
Po ?MTA {
N+&uR!:.C if((lParam&0xc0000000)==0xc0000000){// 有键松开
n;Bb/Z!~ switch(wParam)
Q68~D.V%r {
L0w6K0J4 case VK_MENU:
1UP
{j`-K| MaskBits&=~ALTBIT;
FJ_JaIby break;
B=A!hXNa case VK_CONTROL:
St5;X&Q MaskBits&=~CTRLBIT;
wFMH\a break;
ERPg TZT case VK_SHIFT:
pg{VKrT` MaskBits&=~SHIFTBIT;
F
~A$7 break;
Jg#0g
eU default: //judge the key and send message
TV{GHB!p" break;
BTAbDyH5 }
h)Y] L#R for(int index=0;index<MAX_KEY;index++){
3IxC@QR if(hCallWnd[index]==NULL)
t/|0"\ p continue;
|[],z 8 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
t/ \S9 {
WI\a SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
@i ~ A7L0/ bProcessed=TRUE;
+4yre^gC }
~z^?+MgZ2 }
.xIAep_ }
nJI2IPZ else if((lParam&0xc000ffff)==1){ //有键按下
Y0(4]X \ey switch(wParam)
1!uBzO6/$ {
('x]@ case VK_MENU:
s|%R MaskBits|=ALTBIT;
x3n9|Uud break;
Fz#@ [1, case VK_CONTROL:
>zJHvb)b\ MaskBits|=CTRLBIT;
OIKx:&uIk break;
r+#{\~r7T case VK_SHIFT:
x2v0cR"KL MaskBits|=SHIFTBIT;
y[N0P0r l: break;
$;5Q
mKQ' default: //judge the key and send message
tW/k break;
|r~ u7U\ }
V$ZclV2:Ih for(int index=0;index<MAX_KEY;index++){
|_?e.}K if(hCallWnd[index]==NULL)
>XtfT' continue;
5 `1 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
gnJ8tuS {
a0NiVF-m% SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
jG>W+lq bProcessed=TRUE;
Zn9tG:V }
8-#kY}d. }
3ijPm<wn }
SKC;@? if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
DS?.'"n[u for(int index=0;index<MAX_KEY;index++){
Pn!~U] A$% if(hCallWnd[index]==NULL)
:#:|:q.] continue;
MpOU>\ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
hs7!S+[.$$ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
N
sdpE?V //lParam的意义可看MSDN中WM_KEYDOWN部分
g8O6
b }
@43psq1 }
<,CrE5Pl }
N3"Jo uP return CallNextHookEx( hHook, nCode, wParam, lParam );
<0d2{RQ; }
G*z\
^H 'K4FS(q 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:
J>(X0@eWz TuQGF$n@ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
xM%4/QE+ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
h0<PQZJ ROFZ*@CH< 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
xhP~]akHN7
ZiUb+;JA LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
9FDu{4: {
vRe{B7}p; if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
;<Q%d~$xy} {
~N!HxQ //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
k6C XuU SaveBmp();
;VE y{%nF return FALSE;
m*m),mZ" }
>Y>R1b% …… //其它处理及默认处理
811>dVq3/ }
#gbB// < 2 .3_FXSt `XxnQng 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。
&_L%wV|[ l~E~! MR 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。
X,Na4~JO( e!5} #6Kd 二、编程步骤
BwT[SI<Sg 7}&:07U 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";
_:Qh1 &h krfXvQJwJ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
F` ybe\ xFF!)k # 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;
v@zi?D K Gd!-fqNa'x 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;
?Ek)" l D[+LU( 5、 添加代码,编译运行程序。
hC2Fup1 @ )9H5'Wh# 三、程序代码
O|H: &vrQ *jX ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
s70Z&3A #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
wsmgkg #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
D;+/bll7 #if _MSC_VER > 1000
IQJ"B6U) #pragma once
[NSslVr #endif // _MSC_VER > 1000
]LB_ @# #ifndef __AFXWIN_H__
Z8E<^<| #error include 'stdafx.h' before including this file for PCH
~kZdep^] #endif
G[KjK$.Ts? #include "resource.h" // main symbols
*?<N3Rr* class CHookApp : public CWinApp
x^K4&'</ {
"'CvB0> public:
z>PVv)X CHookApp();
\\SQACN // Overrides
1gHe$dzXk // ClassWizard generated virtual function overrides
yV.p=8: //{{AFX_VIRTUAL(CHookApp)
]c>@RXY' public:
d<-f:}^k0 virtual BOOL InitInstance();
D;YfQQr virtual int ExitInstance();
P}4&J ^ //}}AFX_VIRTUAL
pX%:XpC!h //{{AFX_MSG(CHookApp)
n%3!)/$ // NOTE - the ClassWizard will add and remove member functions here.
| In{5Ek // DO NOT EDIT what you see in these blocks of generated code !
7i($/mNl //}}AFX_MSG
_*~F1% d DECLARE_MESSAGE_MAP()
G!j 9D };
`4*I1WZW LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
:UdW4N- BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
_=$~l^Y[ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
S#]]h/ BOOL InitHotkey();
Xz4q^XJ BOOL UnInit();
8Qg{@#Wr #endif
.{ v$;g SXw r$)4_ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
k3bQ32() #include "stdafx.h"
6!_Wo\_% #include "hook.h"
SrKitSG #include <windowsx.h>
uq3pk3
)W9 #ifdef _DEBUG
8C{&i5kj\E #define new DEBUG_NEW
5qrD~D' #undef THIS_FILE
RQE]=N static char THIS_FILE[] = __FILE__;
q=t!COS #endif
d7^
` #define MAX_KEY 100
Pk;w.)kT #define CTRLBIT 0x04
c+l1l0BA #define ALTBIT 0x02
]+:yfDtZd #define SHIFTBIT 0x01
F>\,`wP #pragma data_seg("shareddata")
StJb-K/_cL HHOOK hHook =NULL;
6Rfv3 UINT nHookCount =0;
/[TOy2/;%b static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
?J2{6,}O*. static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
a*(Zb|g static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
44e]sT.B static int KeyCount =0;
|*?N#0s5h static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
k1,k 9BK #pragma data_seg()
e]1=&:eX#d HINSTANCE hins;
C@Wzg void VerifyWindow();
GXZ="3W | BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
*z[vp2
TN //{{AFX_MSG_MAP(CHookApp)
0se%|Z|8 // NOTE - the ClassWizard will add and remove mapping macros here.
+c_AAMe // DO NOT EDIT what you see in these blocks of generated code!
)>ML7y //}}AFX_MSG_MAP
Vs5 &X+k END_MESSAGE_MAP()
<lB2Nv-, ]L~z9) CHookApp::CHookApp()
)#AYb {
$+PioSq // TODO: add construction code here,
9we];RYK // Place all significant initialization in InitInstance
D:9^^uVp }
XI`_PQco # m|el@) CHookApp theApp;
!po,Z& LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
ZTTA??}Y {
bpsyO>lx/ BOOL bProcessed=FALSE;
n`=S&oKH if(HC_ACTION==nCode)
b!g)/%C
{
rv[BL.qV if((lParam&0xc0000000)==0xc0000000){// Key up
NATi)A"TZ switch(wParam)
?e-rwaW {
Y<;C>Rs
case VK_MENU:
!$HuH6_[ MaskBits&=~ALTBIT;
&K]|{1+ break;
6No.2Oo case VK_CONTROL:
;s3@(OnjZ MaskBits&=~CTRLBIT;
fyUW;dj break;
gS(JgN case VK_SHIFT:
TJP;!uX MaskBits&=~SHIFTBIT;
'tTlBf7# break;
Db2#QQ default: //judge the key and send message
?Ho$fGz break;
p3fVw]N }
>]}VD "\ for(int index=0;index<MAX_KEY;index++){
RCqL~7C+ k if(hCallWnd[index]==NULL)
TPb&";4ROf continue;
a?Om;-i2`S if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
ip'v<%,Q3" {
-T+yS BO_3 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
[
2@Lc3< bProcessed=TRUE;
E2
'Al6^C }
Ew}GPJ }
H?opG<R=ek }
fx 0 8>r
else if((lParam&0xc000ffff)==1){ //Key down
w8o?wx* switch(wParam)
I-.?qcy~ {
gu3)HCZ case VK_MENU:
.aZB?MW MaskBits|=ALTBIT;
>ptI!\i} break;
fo}@B&=4 case VK_CONTROL:
N0fE*xo MaskBits|=CTRLBIT;
'PMzm/;8st break;
k'$7RjCu case VK_SHIFT:
nb5%a MaskBits|=SHIFTBIT;
D622:Y886 break;
M]\"]H? default: //judge the key and send message
L%9yFg%u break;
|q o3
E }
dkEnc for(int index=0;index<MAX_KEY;index++)
Zf u" 8fX {
!oV' if(hCallWnd[index]==NULL)
/9y'UKl7[ continue;
:+DAzjwO< if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
[0+5 Gx {
u*;53 43 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
F7x< V=4{ bProcessed=TRUE;
]*S_fme }
-JF|770i }
MD:kfPQ }
WY~}sE if(!bProcessed){
;rta#pRn for(int index=0;index<MAX_KEY;index++){
zGFW?|o< if(hCallWnd[index]==NULL)
?yz} continue;
nuv$B > if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
EZiGi[t7 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
>BQF< }
]O&A:Us }
=09j1:''<d }
*DoEDw return CallNextHookEx( hHook, nCode, wParam, lParam );
~h[lu^ZSi }
{_MU0=7c\ ' *p-` BOOL InitHotkey()
J>Rt2K {
=Jl1D*B* if(hHook!=NULL){
Pq7tNM E nHookCount++;
TAJ 9Y< return TRUE;
Y=rW.yK8 }
Js#c9l{{ else
zZh`go02E hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
M!6bf if(hHook!=NULL)
TbU9
<mY nHookCount++;
|V~P6o(/ return (hHook!=NULL);
*&2#;mf3 }
qV$',U*+T BOOL UnInit()
<db/. A3 {
t_VHw'~" if(nHookCount>1){
:* /`` nHookCount--;
C1rCKKh return TRUE;
:~)Q] G1Nj }
$v oyXi`* BOOL unhooked = UnhookWindowsHookEx(hHook);
+#H8d1^5 if(unhooked==TRUE){
izWl5}+'B nHookCount=0;
3S2'JOTY hHook=NULL;
i+cGw }
+[}]a3) return unhooked;
/~tfP }
6k3l/ ~R ;<X3AhF BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
'}YXpB {
K
:q-[\G BOOL bAdded=FALSE;
2RXGY for(int index=0;index<MAX_KEY;index++){
K((Kd&E if(hCallWnd[index]==0){
quUJ%F hCallWnd[index]=hWnd;
z=Vvb HotKey[index]=cKey;
;^8^L'7cr HotKeyMask[index]=cMask;
&%r#eB?7 bAdded=TRUE;
22r01qH KeyCount++;
O}f(h5!k break;
@Q1jH~t }
jh0$:6 `C }
nG*6ic return bAdded;
~D=@4(f8| }
dO// yEqmB4^- BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
yaR; {
f}'gg BOOL bRemoved=FALSE;
}Voh5*$E` for(int index=0;index<MAX_KEY;index++){
<d5vVn if(hCallWnd[index]==hWnd){
I!<v$ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Qy/bzO hCallWnd[index]=NULL;
c _a$g HotKey[index]=0;
+l/j6)O`(m HotKeyMask[index]=0;
S'JeA>L bRemoved=TRUE;
KE&}*Nf[ KeyCount--;
d$,i?d, break;
C;)
xjZiR }
:{
T#M$T }
3ElpS^2W }
l=]vC +mU return bRemoved;
XZ&v3ul }
Yr= mLT|JN 1;gSf.naG void VerifyWindow()
2!otVz!Mh {
">QY'r for(int i=0;i<MAX_KEY;i++){
bgK(l d` if(hCallWnd
!=NULL){ rpT<cCem1
if(!IsWindow(hCallWnd)){ N]<gHGj}
hCallWnd=NULL; XfrnM^oty
HotKey=0; _dBU6U:V
HotKeyMask=0; h*9o_
KeyCount--; l.W:6",w
} dJ^`9W
} G0Eq}MyF
} /a|NGh%
} [;f"',)y,
w;$+7
BOOL CHookApp::InitInstance() {|E7N"Qzg
{ ,h._iO)I^
AFX_MANAGE_STATE(AfxGetStaticModuleState()); p,8Z{mLn
hins=AfxGetInstanceHandle(); bN&da
[K
InitHotkey(); ,s76]$%4
return CWinApp::InitInstance(); Q8q_w2s,
} Pvw%,=41O
w$ {
int CHookApp::ExitInstance() 7dJaWD:&
{ B~#@fIL
VerifyWindow(); y)E2=JQA/
UnInit(); ) :@%xoF5
return CWinApp::ExitInstance(); :GYv9OG
} R4(8]oUW
/6c10}f
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file lpUtNy
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) P.B'Gh#^
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ ]c2| m}I{:
#if _MSC_VER > 1000 OJ 5 !+#>
#pragma once mD)O\.uA
#endif // _MSC_VER > 1000 ix+x-G
q_&IZ,{Vk
class CCaptureDlg : public CDialog *~uuCLv_
{ { bn#:75r
// Construction !?*!"S-Sl
public: Y%l3SB,5L
BOOL bTray; ~Wm}M
BOOL bRegistered; :a@z53X@M
BOOL RegisterHotkey(); $SVGpEw
UCHAR cKey; )+,jal^7
UCHAR cMask; 9`{2 h$U
void DeleteIcon(); Rk[ * p
void AddIcon(); ItPK
UINT nCount; CM1a<bV<
void SaveBmp(); *KH@u
CCaptureDlg(CWnd* pParent = NULL); // standard constructor eBIR*TZ):
// Dialog Data "%t`I)
//{{AFX_DATA(CCaptureDlg) r_E)HL/A
enum { IDD = IDD_CAPTURE_DIALOG }; U.'@S8
CComboBox m_Key; n;`L5
BOOL m_bControl; 5z ^UQq
BOOL m_bAlt; 9%14k
BOOL m_bShift; E0]h|/A]
CString m_Path; 34kd|!e,
CString m_Number; l|em E
^
//}}AFX_DATA \q'fB?bS^
// ClassWizard generated virtual function overrides )N6[rw<