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:
v\5`n@}4
cY|@s?3NND 一、实现方法
z
AY
-Y E.CG 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:
d;).| .}P +,eF(VS! #pragma data_seg("shareddata")
WogCt, HHOOK hHook =NULL; //钩子句柄
RuOse9 UINT nHookCount =0; //挂接的程序数目
<"7Wb"+ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Pe@*')o* static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
>{"E~U static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
= @lM* static int KeyCount =0;
Uf|@h static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
SYgkYR #pragma data_seg()
I8\R7s3 ZD4:'m`T/ 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。
sTxbh2 mwF{z.t" 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:
!"
@<! =V:Al BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
tjcsT> cKey,UCHAR cMask)
-e_pw,5c ' {
+_ $!9m BOOL bAdded=FALSE;
Ag;Ybk[ for(int index=0;index<MAX_KEY;index++){
Hr*xA x if(hCallWnd[index]==0){
2xv[cpVi hCallWnd[index]=hWnd;
} ;d= HotKey[index]=cKey;
Z 3-=TN HotKeyMask[index]=cMask;
OS=~<ba bAdded=TRUE;
+]e) :J KeyCount++;
-CTLQyj) break;
a*nCvZ
}
_DYe<f. }
Pt/F$A{Cj return bAdded;
V" KuwM }
`F_R J.g*p //删除热键
xr31<4B BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
WFvVu3 {
Dt'bbX'edw BOOL bRemoved=FALSE;
t* =i8`8 for(int index=0;index<MAX_KEY;index++){
aoGns46Y if(hCallWnd[index]==hWnd){
<}}u'5;^?x if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
RH;A|[7T& hCallWnd[index]=NULL;
7H?lR~w HotKey[index]=0;
Ru$%gh>v HotKeyMask[index]=0;
/'bX}H(dq bRemoved=TRUE;
{@[#0gPH KeyCount--;
X: QRy9] break;
{3``B#} }
j 5 bHzcv }
4G j }
Fh}GJE return bRemoved;
)c<[@::i }
QvlVjDIy * b"aJ<+ 8>|<m'e^\r DLL中的钩子函数如下:
Q3[nS(#Z/= r%`3*<ALV) LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
D@m3bsMwe {
hwSxdT6 BOOL bProcessed=FALSE;
?2K~']\S if(HC_ACTION==nCode)
.lGN
Fx {
D4T(Dce if((lParam&0xc0000000)==0xc0000000){// 有键松开
cvjZ$Fcc%( switch(wParam)
P}he}k&IR {
C-&s$5MzGb case VK_MENU:
'N\nJz} MaskBits&=~ALTBIT;
5dL! e<< break;
EnEaUb?P case VK_CONTROL:
RP9~n)h~b
MaskBits&=~CTRLBIT;
U[hokwZ break;
P&*e\"{ case VK_SHIFT:
'wo}1^V MaskBits&=~SHIFTBIT;
X*`b}^T break;
.+5;AtN default: //judge the key and send message
hSaw)g`w break;
dA0o{[o= }
fjm3X$tR for(int index=0;index<MAX_KEY;index++){
tQ)l4Y 8 if(hCallWnd[index]==NULL)
>KJE *X@s continue;
wNMA)S if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
vg5fMH9ZZ {
r>t|.=! SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
07>D G# bProcessed=TRUE;
m[hHaX }
Q}1qt4xy* }
a@!O}f* }
|wyua@2 else if((lParam&0xc000ffff)==1){ //有键按下
$v=(`= switch(wParam)
}s.\B
{
Cjj(v7[E case VK_MENU:
H:mcex MaskBits|=ALTBIT;
Li\b,_C break;
b\H,+|iK case VK_CONTROL:
9jllW[`2F MaskBits|=CTRLBIT;
xj JoWB break;
+;
=XiB5R case VK_SHIFT:
/$j,p E= MaskBits|=SHIFTBIT;
}'h\;8y break;
d,o|>e$ default: //judge the key and send message
}*7Gq break;
~31-)*tJ] }
4\ny]A:~ for(int index=0;index<MAX_KEY;index++){
DK|/|C}6 if(hCallWnd[index]==NULL)
G#6O'G
N continue;
:e\M~n+y if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
9!6u Yf+ {
k-sBf Jy\ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
jgBJs^JgYG bProcessed=TRUE;
+[pJr-k }
uIR }
u\)q.` }
;.7]zn.X]2 if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
J,k.*t: for(int index=0;index<MAX_KEY;index++){
q0@b d2} if(hCallWnd[index]==NULL)
}{.V^; continue;
0&c<1; if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
^O**ZndB/ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Cf@N>N#t) //lParam的意义可看MSDN中WM_KEYDOWN部分
%< Jj[F }
%/R[cj8 }
/km0[M }
LtK,_j return CallNextHookEx( hHook, nCode, wParam, lParam );
avUdvV- }
+d3h @gp 35YDP|XZb 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:
@ZtvpL}e $Y%,?>AL< BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
3H%bbFy BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
S~GS:E# 5E2T*EXSh 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
R%Xz3Z&| f_IsY+@ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
-90X^] {
:* J! if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
+<WNAmh
{
ge%tj O //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
m21H68y SaveBmp();
cZAf?,>u return FALSE;
v=-T3
n }
x'V:qv*O …… //其它处理及默认处理
y>ePCDR3 }
>vNE3S_ 8[oZ>7LMzC !)FKF7' 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
3GXmyo:o$ A9LVS&52 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。
mh#_lbe' au/5` 二、编程步骤
'Ge8l%p SI7r`'7A' 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";
qrcir-+ V|pO";%>, 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
MkM`)g 5
#X0Y8:vj 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;
1c4:'0 %5j*e 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;
Y5<W"[B! :%IB34e 5、 添加代码,编译运行程序。
^-(DokdBn 8#RL2)7Uy` 三、程序代码
`|4k>5k n{"a0O ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
U Fyk%#L #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
Oki{)Ssy #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
"fu@2y4^ #if _MSC_VER > 1000
Gl9,!"A #pragma once
I~,b ZA #endif // _MSC_VER > 1000
&PFK0tY #ifndef __AFXWIN_H__
_[N*k" #error include 'stdafx.h' before including this file for PCH
fj[Kbo 7!h #endif
M} Mgz #include "resource.h" // main symbols
ZN!<!"~ class CHookApp : public CWinApp
{}BAQ9|q {
3lN@1jlh public:
</_.+c [ CHookApp();
0Q[;{}W} // Overrides
2 e&M/{ // ClassWizard generated virtual function overrides
"1rT>
ASWI //{{AFX_VIRTUAL(CHookApp)
mnU8i=v0A public:
p+${_w>pl{ virtual BOOL InitInstance();
'>t'U?7w< virtual int ExitInstance();
5`q#~fJ2 //}}AFX_VIRTUAL
9y j'->dL //{{AFX_MSG(CHookApp)
XjTu`?Na; // NOTE - the ClassWizard will add and remove member functions here.
NBA`@K~4 // DO NOT EDIT what you see in these blocks of generated code !
MaZS|Zei[ //}}AFX_MSG
)oZ2,]us! DECLARE_MESSAGE_MAP()
iK8jX? };
Myh?=:1~(c LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
Raf-I+ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
-f"{%<Q BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
/?*ut&hwv BOOL InitHotkey();
ix5<h } BOOL UnInit();
a?*pO`<J{ #endif
;dTxQ_: Fm+V_.H/; //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
rv2;)3/* #include "stdafx.h"
Y.%Vvg4z3 #include "hook.h"
]^<\a=U #include <windowsx.h>
uS!V_] #ifdef _DEBUG
T5wVJgN> #define new DEBUG_NEW
Nr`v|_U #undef THIS_FILE
@IOl0db static char THIS_FILE[] = __FILE__;
_!9I
f #endif
Op hD_^ #define MAX_KEY 100
GF*uDJ Kp #define CTRLBIT 0x04
9rT"_d# #define ALTBIT 0x02
hd)WdGJp #define SHIFTBIT 0x01
otQ
G6 #pragma data_seg("shareddata")
\+k~p:d_8 HHOOK hHook =NULL;
vILgM\or UINT nHookCount =0;
)-25?B static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
`tl -] ^Y2 static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
BqtN= static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
p:3w8#)MZ static int KeyCount =0;
$ SZIJe"K static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
<Ik5S1<h$H #pragma data_seg()
#It!D5A HINSTANCE hins;
kkXe= f% void VerifyWindow();
Jv!f6*&< BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
4|DN^F~iut //{{AFX_MSG_MAP(CHookApp)
JY3!jtv // NOTE - the ClassWizard will add and remove mapping macros here.
(t,mtdD#1 // DO NOT EDIT what you see in these blocks of generated code!
:0Fc E,1 //}}AFX_MSG_MAP
;Pvnhy END_MESSAGE_MAP()
k;r[m,$ EBpg CHookApp::CHookApp()
HstL'{&,-m {
yGH')TsjD // TODO: add construction code here,
+P.JiH`\= // Place all significant initialization in InitInstance
Is9.A_0h }
38%"#T3# CiTWjE?|7 CHookApp theApp;
9fsc>9 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
)M@^Z(W/a {
F1p|^hYDW BOOL bProcessed=FALSE;
^!x qOp! if(HC_ACTION==nCode)
n%!50E6*: {
1yTw*vH F if((lParam&0xc0000000)==0xc0000000){// Key up
T#HF!GH] switch(wParam)
"tu*(>'~5 {
W!1
B~NH# case VK_MENU:
k7M{+X6[ MaskBits&=~ALTBIT;
UU '9 break;
Y]i:$X]C?X case VK_CONTROL:
c)c_Qv MaskBits&=~CTRLBIT;
z2q!_ ~ break;
U@:l~xJ case VK_SHIFT:
<"av /`; MaskBits&=~SHIFTBIT;
hPUZ{#;n break;
?"@SxM~\ default: //judge the key and send message
61*b|.sl'# break;
rY)m"'puP }
C#RueDa. for(int index=0;index<MAX_KEY;index++){
Pd~z%VoO if(hCallWnd[index]==NULL)
U\>k>|Jr{ continue;
".?y!VY if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
\U'*B}Sz {
#r]GnC, SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
C}\kp0mz bProcessed=TRUE;
.:tR*Kst`7 }
"WH
&BhQYD }
]NKz5[9D }
EW/N H&{ else if((lParam&0xc000ffff)==1){ //Key down
Pt'=_^Io switch(wParam)
2L=(-CH9] {
oUB9)C~ case VK_MENU:
mFE7#OM MaskBits|=ALTBIT;
p$<){,R break;
<)o xs]< case VK_CONTROL:
4}]In/yA MaskBits|=CTRLBIT;
/K_*Drk> break;
01IfvK case VK_SHIFT:
Gi&/`vm MaskBits|=SHIFTBIT;
(V"7H break;
E&Sr+D aPD default: //judge the key and send message
@==
"$uRw break;
VYrs4IFT$ }
A$?o3--#]G for(int index=0;index<MAX_KEY;index++)
n% s$!R-\ {
2(R{3E4. if(hCallWnd[index]==NULL)
\3)U~[O>: continue;
<iM}p^jX9 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
DXK\3vf Ot {
9xL`i-7] SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
2-^['R bProcessed=TRUE;
51'V[tI;8 }
EpENhC0 }
vb`: }
Qd}h:U^ if(!bProcessed){
'(8}
<(% for(int index=0;index<MAX_KEY;index++){
ryTtGx%a if(hCallWnd[index]==NULL)
:kXxxS continue;
1119Y eL if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
P+,YWp SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
#*G}v%Ow/u }
^;@!\Rc }
vQ[ TcV }
e(9K.3@{ return CallNextHookEx( hHook, nCode, wParam, lParam );
mHNqzdaa }
~~#/jULbV C 6d#+ BOOL InitHotkey()
ZV[-$ {
&CfzhIi*! if(hHook!=NULL){
XL(2Qk nHookCount++;
&cf_?4 return TRUE;
F^Mt}`O }
z@2nre else
<p[RhP hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
TaZlfe5z if(hHook!=NULL)
r6kQMFA nHookCount++;
&p=(0$0&- return (hHook!=NULL);
+lJD7=%K]Z }
+^a@U^V BOOL UnInit()
MU1T="N^+ {
`[tYe < if(nHookCount>1){
QtOT'<2t] nHookCount--;
Z
FIgKWZ' return TRUE;
7Ur'@wr }
Qe=eer~jI BOOL unhooked = UnhookWindowsHookEx(hHook);
:kucDQE({? if(unhooked==TRUE){
q{7+N1
" nHookCount=0;
5_SxX@fW% hHook=NULL;
qwo{34 }
&>XSQB(&% return unhooked;
[O6JVXO> }
"mcuF]7F ?)4c!3# BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Q>\9/DjUp {
0|?DA12Z BOOL bAdded=FALSE;
QW&@>i for(int index=0;index<MAX_KEY;index++){
{;hRFQ^b if(hCallWnd[index]==0){
N ^H
H&~V hCallWnd[index]=hWnd;
T7*p!0 HotKey[index]=cKey;
M5+K[Ir/y9 HotKeyMask[index]=cMask;
j g_;pn bAdded=TRUE;
(@xr/9:i KeyCount++;
S#|5&SR break;
{|tMN,Z }
wE_#b\$=b }
9bD ER return bAdded;
|LE*R@|3$ }
^2mCF hle@= e/n BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
1i
6>~ {
Fw6x
(j" BOOL bRemoved=FALSE;
pbqJtBBDDS for(int index=0;index<MAX_KEY;index++){
]$A6krfh| if(hCallWnd[index]==hWnd){
_\AT_Zmy if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
</qli-fXB} hCallWnd[index]=NULL;
Yk5Cyq HotKey[index]=0;
"R-Pe\W HotKeyMask[index]=0;
2}.EFQp+ bRemoved=TRUE;
~Yl%{1 KeyCount--;
o]0\Km break;
M\=/i\- }
/^Zgv-n }
0+_:^z }
yzz(<s:o/ return bRemoved;
)H<F([Jri }
y;tX`5(fe A<cnIUW void VerifyWindow()
K<"Y4O#] {
9icy&' for(int i=0;i<MAX_KEY;i++){
:4S~}}N if(hCallWnd
!=NULL){ 5~xv"S(E}
if(!IsWindow(hCallWnd)){ 4+au6ABy
hCallWnd=NULL; /Y*6mQ:
HotKey=0; U\;mM\2rE
HotKeyMask=0; }I#,o!)Vd
KeyCount--;
Tv~Ys#
} XNB4KjT
} CGCSfoS9f
} I)f54AX
} > ^d+;~Q;
U("m}^
BOOL CHookApp::InitInstance() EN~ha:9
{ EP]O J$6I
AFX_MANAGE_STATE(AfxGetStaticModuleState()); l1}HJmom
hins=AfxGetInstanceHandle(); o%?~9rf]]
InitHotkey(); M\be a
return CWinApp::InitInstance(); 8f-B-e?k
} RQd5Q.
~@EBW3>~5
int CHookApp::ExitInstance() Rs1JCP=d8
{ "\x\P)j0>
VerifyWindow(); 2]-xmS>|b
UnInit(); `Z~\&r=
return CWinApp::ExitInstance(); JJE0q5[
} REKv&^FLN
W$?Bsz)
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file !$.h[z^
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) n ,CMGe^:
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ |PW.CV0,
#if _MSC_VER > 1000 <Z9N}wY,8
#pragma once F7qQrE5bl
#endif // _MSC_VER > 1000 sBWLgJz?C
N^By#Z
class CCaptureDlg : public CDialog "%{J$o
{ #wZBWTj.
// Construction J l9w/T
public: p+|(lrYC
BOOL bTray; jRo4+8
BOOL bRegistered; xouy|Nn'
BOOL RegisterHotkey(); <LOas$
UCHAR cKey; 4Nz]LK%@
UCHAR cMask; \J3n[6;
void DeleteIcon(); K@+(6\6I
void AddIcon(); rJ_fg$.<
UINT nCount; '5m`[S-IU
void SaveBmp(); 'Lv>!s 7
CCaptureDlg(CWnd* pParent = NULL); // standard constructor "r.eN_d
// Dialog Data ao.v]6a
//{{AFX_DATA(CCaptureDlg) nXcOFU
enum { IDD = IDD_CAPTURE_DIALOG }; d"JI4)%
CComboBox m_Key; P*sb@y>}O
BOOL m_bControl; )K^5+oC17
BOOL m_bAlt; \l9S5%L9
BOOL m_bShift; CGN:=D<
CString m_Path; Dh{sVRA
CString m_Number; b0"R |d[i
//}}AFX_DATA @mrGG F
// ClassWizard generated virtual function overrides LzJNQd'
//{{AFX_VIRTUAL(CCaptureDlg) !)TO2?,^
public: ,mW-O!$3W
virtual BOOL PreTranslateMessage(MSG* pMsg); 8t
Ef>
protected: ?g #4&z.
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support =f{YwtG
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); {`CmE/`{
//}}AFX_VIRTUAL &nEQ