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:
C`qV+pV `mD!z.`U 一、实现方法
6/g
82kqpk vA6onYjA 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:
g#6R( AH'3
5Kf) #pragma data_seg("shareddata")
/!>OWh*~ HHOOK hHook =NULL; //钩子句柄
FY)]yz UINT nHookCount =0; //挂接的程序数目
?9eiT:2 static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
~bzac2Rp static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
Fo;J3<U) static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
2PeMt^ static int KeyCount =0;
=)jo}MB static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
W79.Nj2` #pragma data_seg()
An?#B4: 47{5{/B- 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。
2(\PsN w! oy[ px9Wx 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:
A{)pzV25 @}PX:*c BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
g__s(
IJ cKey,UCHAR cMask)
PC255 {
5"1wz BOOL bAdded=FALSE;
Gi@c`lRd1 for(int index=0;index<MAX_KEY;index++){
)OQ<H.X if(hCallWnd[index]==0){
bV'r9&[_6 hCallWnd[index]=hWnd;
n?D/bX p HotKey[index]=cKey;
74
)G.! HotKeyMask[index]=cMask;
KMqGWO* bAdded=TRUE;
vQ2{+5!| KeyCount++;
?D9iCP~~ break;
d2U?rw_ }
k}}'fA }
#E\6:UnT return bAdded;
XMP4YWuVc }
>@?mP$;= //删除热键
^PJN$BJx BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
-j rAk {
}$uwAevP{y BOOL bRemoved=FALSE;
7042?\\= for(int index=0;index<MAX_KEY;index++){
Vom,^`} if(hCallWnd[index]==hWnd){
`Z{s,!z if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
,(sE|B#s hCallWnd[index]=NULL;
3'A0{(b HotKey[index]=0;
&0G9v HotKeyMask[index]=0;
F9las#\J bRemoved=TRUE;
o.zP1n|G~r KeyCount--;
o>yXEg break;
6r@>n_6LY }
*D[yA }
Q9f5} }
&{qKoI] return bRemoved;
^k^?>h }
KC(z TY 'q}f3u > Kf$(7FT'` DLL中的钩子函数如下:
i<tJG{A= J
48$l(l3 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
kou7_4oS {
X+,0;% p BOOL bProcessed=FALSE;
$XkO\6kh if(HC_ACTION==nCode)
PVljb=8F {
|:2B )X if((lParam&0xc0000000)==0xc0000000){// 有键松开
4qsxlN>4O switch(wParam)
k w
{
{t|#>UCK case VK_MENU:
_]D
6m2R MaskBits&=~ALTBIT;
iG~&uEAJ break;
5.yiNWh case VK_CONTROL:
YvP62c \ MaskBits&=~CTRLBIT;
aiE\r/k8s break;
dmLx $8 case VK_SHIFT:
5U]@
Y? MaskBits&=~SHIFTBIT;
UH\{:@GjNO break;
`/!FZh< default: //judge the key and send message
1:@ScHS break;
4UzXTsjM7 }
>@4AxV\ for(int index=0;index<MAX_KEY;index++){
B/n~ $ if(hCallWnd[index]==NULL)
CW/L(RQ continue;
15aPoxo> if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
GY0OVAW6'c {
Gui[/iY,F SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
jWh)bsqI! bProcessed=TRUE;
%4YSuZg }
Y(?SE< 4R }
\l
8_aj }
g4 +Hq * else if((lParam&0xc000ffff)==1){ //有键按下
E_Y!in
70 switch(wParam)
u5KAwMw%Q {
%Lh+W<; case VK_MENU:
~ kDJ-V MaskBits|=ALTBIT;
=9^}>u break;
) vVf- zU case VK_CONTROL:
Acd@BL* MaskBits|=CTRLBIT;
Z*h}E break;
fy|I3 case VK_SHIFT:
n'JS- MaskBits|=SHIFTBIT;
W@'*G*f break;
8.I3%u default: //judge the key and send message
1~LfR break;
T-/3
A%v }
0]=Bqyg for(int index=0;index<MAX_KEY;index++){
49}WJC7
) if(hCallWnd[index]==NULL)
9e
vQQN6D| continue;
T3 4Z#PFwe if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Sl<1Rme=w {
PCV#O63[ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
ozl!vf# kv bProcessed=TRUE;
Y3(I;~$! }
|k%1mE(+=s }
KU+\fwYpnk }
]IeLKcn if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
8Djki] for(int index=0;index<MAX_KEY;index++){
4*5 e0:O if(hCallWnd[index]==NULL)
3?L[ohKH?: continue;
U0{)goN. if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
7y)Ar 8!D SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
u%I%4 gM //lParam的意义可看MSDN中WM_KEYDOWN部分
2efdJ&eIV }
s@y;b0$gk }
Hz==,NR-W }
6iF&!Fd>J return CallNextHookEx( hHook, nCode, wParam, lParam );
_G'A]O/BZD }
>kmgYWG 1\Pjz
Lj 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:
|_-w{2K .9,x_\|G* BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
M5t.l ( BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
T:H~Y+qnt Iwh0PfWJ 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:
a l6y=;\jZ <mVFC LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
t,*1=S5 {
n00J21 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
OJJ [Er1 {
(c^ {T) //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
Fu5Y<*x SaveBmp();
g0}jE%) return FALSE;
4 dLnX3 v }
Rt&5s)O' …… //其它处理及默认处理
llWY7u" }
Th*}U& \0_jmX]p n ]D io 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。
]vn*eqd vTK8t:JQ~ 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。
/~f[># jX(${j< 二、编程步骤
U=69q] (FaYagD 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";
dJJq]^| ~9yKMUf 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
QJrXn6` r=vY-p 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;
% -AcA Jvsy
6R 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;
f5b|,JJ h$6'9rL&i 5、 添加代码,编译运行程序。
dzAumWoh \/;c^!(< 三、程序代码
?<
teHFj &ZkJ,- ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
xRhGBb{@s #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
<2&qIvHL #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
:(m, 06K #if _MSC_VER > 1000
}zsIp, #pragma once
9lR6:}L7 #endif // _MSC_VER > 1000
}5(_gYr #ifndef __AFXWIN_H__
L[Z^4l_! #error include 'stdafx.h' before including this file for PCH
R%\3[ #endif
&oB*gGRw=7 #include "resource.h" // main symbols
Zy;jp*Q class CHookApp : public CWinApp
t=@d`s:R2 {
.S#i/A'x public:
9< 07# 8c. CHookApp();
f:&JKB)N // Overrides
R+(f~ j' // ClassWizard generated virtual function overrides
Xy 4k;+ //{{AFX_VIRTUAL(CHookApp)
~/-SKGzo- public:
+pYwc0~ virtual BOOL InitInstance();
rA B=H*|6 virtual int ExitInstance();
Y<VX.S2kf //}}AFX_VIRTUAL
Xn%7{%;h //{{AFX_MSG(CHookApp)
#-G@ p // NOTE - the ClassWizard will add and remove member functions here.
C=q&S6/+ // DO NOT EDIT what you see in these blocks of generated code !
\y=28KKc:c //}}AFX_MSG
g_P98_2f.k DECLARE_MESSAGE_MAP()
bO/r1W };
N~CQh=< LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
nA("
cD[, BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
fg#e*7Odn BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
U2<q dknB
BOOL InitHotkey();
=5B5 BOOL UnInit();
6O6B8 #endif
E=,5%>C0#%
f&^}yqmuE //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
]J!#"m-] #include "stdafx.h"
F) Q[ cai #include "hook.h"
?;`GCE #include <windowsx.h>
!wpK
+.D #ifdef _DEBUG
\ 9V_[xD+ #define new DEBUG_NEW
ejkUNCKQt #undef THIS_FILE
hOZTD0 static char THIS_FILE[] = __FILE__;
dO1m #endif
/N*<Fq7w~ #define MAX_KEY 100
l{C]0^6>i #define CTRLBIT 0x04
:M{
)&{D #define ALTBIT 0x02
xPUukmG:B #define SHIFTBIT 0x01
Kn5C #pragma data_seg("shareddata")
H.{Fw j4 HHOOK hHook =NULL;
iZdl0;16[ UINT nHookCount =0;
"'Fvt-<^S7 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
1z&"V}y static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
tyW[i8)O} static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
\{ QH^ static int KeyCount =0;
]] 0 M static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
#'%ii,;wQ #pragma data_seg()
NwYQ6VEA
HINSTANCE hins;
R+uZi~ void VerifyWindow();
T|S-?X, BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
!BkE-9v?w //{{AFX_MSG_MAP(CHookApp)
5 cQ]vb // NOTE - the ClassWizard will add and remove mapping macros here.
$+44US // DO NOT EDIT what you see in these blocks of generated code!
dZ(Z]`L,B //}}AFX_MSG_MAP
1/:vFX END_MESSAGE_MAP()
L{>rN`{ s,[I_IiPf CHookApp::CHookApp()
8i73iTg( {
-th.(eAx // TODO: add construction code here,
YiuV\al // Place all significant initialization in InitInstance
"OI$PLK }
iN'T^+um= CT|0KB& CHookApp theApp;
^J7q,tvbJ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
ATc!c + {
jmq^98jB BOOL bProcessed=FALSE;
}\8-&VoY#X if(HC_ACTION==nCode)
b1IAp >*2l {
By7lSbj if((lParam&0xc0000000)==0xc0000000){// Key up
v ,h"u switch(wParam)
*:
FS/ir {
>T[Y>] case VK_MENU:
~YW;' MaskBits&=~ALTBIT;
JLWm9c+UTG break;
RY)x"\D case VK_CONTROL:
pwHe&7e# MaskBits&=~CTRLBIT;
ZyNgG9JL] break;
x{w|Hy case VK_SHIFT:
"u~` ZV( MaskBits&=~SHIFTBIT;
)_ !a: break;
7)#JrpTj% default: //judge the key and send message
5D7 L)> break;
lj&\F|-i }
4pXY7+e2' for(int index=0;index<MAX_KEY;index++){
s1W n.OGR4 if(hCallWnd[index]==NULL)
3*%+NQIj continue;
6j{ynt if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Px?"5g#+ {
.c<U5/ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Lhg bProcessed=TRUE;
"\;n t5L }
*<
fJgc"3 }
kP('X/ }
"-Nyf else if((lParam&0xc000ffff)==1){ //Key down
&DYC3*)Jih switch(wParam)
q*4@d)_& {
j&S.k case VK_MENU:
`]GL3cIh: MaskBits|=ALTBIT;
7W4m&+ break;
m$_l{|4z case VK_CONTROL:
{*hGe_^ MaskBits|=CTRLBIT;
y[jp)&N` break;
OC,yL Q case VK_SHIFT:
o\it]B MaskBits|=SHIFTBIT;
6A>bm{`c: break;
INk|NEX default: //judge the key and send message
(?,jnnub break;
xp3^,x;\X }
QRl+7V for(int index=0;index<MAX_KEY;index++)
5'{QMnfB {
h1 "# if(hCallWnd[index]==NULL)
Q8l vwip continue;
:si&A;k if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
M54czo=l {
"BpDlTYM SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
^P [#YO bProcessed=TRUE;
I=[0 9o }
I}y6ke! }
/:\27n }
]-X\n
if(!bProcessed){
!]mo.zDSW5 for(int index=0;index<MAX_KEY;index++){
(C`nBiL< if(hCallWnd[index]==NULL)
4V]xVma continue;
2|RxowXZ" if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
!_c6 `oW SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
!](Mt?e }
_E-{*,7bZS }
2.{<C.BK{ }
U/v)6:j)4R return CallNextHookEx( hHook, nCode, wParam, lParam );
"J}B
lB }
^pfM/LQ@ j[$+DCO#|m BOOL InitHotkey()
f::^zAV {
]5ibg"{S if(hHook!=NULL){
trLxg H_Y nHookCount++;
hOIg7=v return TRUE;
;U tEHvE* }
RJT55Rv{ else
=3V4HQi hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
~xPetkl@ if(hHook!=NULL)
oOXJ7|n nHookCount++;
[5b[ztN% return (hHook!=NULL);
K6~')9Q }
EjEXev<] BOOL UnInit()
n|QA\,= {
`q\v~FT if(nHookCount>1){
EW)r/Av:, nHookCount--;
$x+ P)5) return TRUE;
FY+@fy }
0r&FH$ BOOL unhooked = UnhookWindowsHookEx(hHook);
DuQ:82 3b if(unhooked==TRUE){
:2{ [f+ nHookCount=0;
lL'K1%{+
\ hHook=NULL;
t#]VR7] }
QYBLU7 return unhooked;
D2:ShyYAS }
:c[T@[ RC/&dB BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
un,W{*s8* {
AZJ|.mV q BOOL bAdded=FALSE;
MAc/ T.[ for(int index=0;index<MAX_KEY;index++){
`E>o:tff if(hCallWnd[index]==0){
8Tc:TaL hCallWnd[index]=hWnd;
qNkX:|j HotKey[index]=cKey;
W;,RU8\f HotKeyMask[index]=cMask;
$@dPIq4o;} bAdded=TRUE;
bXHtw}n KeyCount++;
=G rg break;
6HVGqx }
LyNur8 Zi }
V F"c} return bAdded;
v[m1R' }
2l8z/o 7v mj2sbRiSR= BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
F2=#\U$ {
u,@x7a,z BOOL bRemoved=FALSE;
Pv8AWQQJ for(int index=0;index<MAX_KEY;index++){
k0DX|O8mXV if(hCallWnd[index]==hWnd){
[rhK2fr:i if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
>P ygUY
d hCallWnd[index]=NULL;
8O^z{Yh7 HotKey[index]=0;
a'\fS7aE0l HotKeyMask[index]=0;
sQY0Xys<4 bRemoved=TRUE;
JG'&anbm KeyCount--;
LS1}j WU! break;
!z?:Y#P3 }
V ;M'd@ }
`&A-m8X }
M5LqZyY return bRemoved;
}Ot2; T }
u O~MT7~[X *wz6 2p void VerifyWindow()
d[KG0E5` {
mz .uK2l{ for(int i=0;i<MAX_KEY;i++){
*IC9))PGJ if(hCallWnd
!=NULL){ %|?PG i@5
if(!IsWindow(hCallWnd)){ HBgt!D0MZ
hCallWnd=NULL; q?Mmkh)g
HotKey=0; cz*Z/5XH
HotKeyMask=0; Q<Th*t
KeyCount--; {UEZ:a
} qr7_3
} 5A"OL6ty
} Z <tJ+
} l,M?
>c8EgSZJ
BOOL CHookApp::InitInstance() J$i5A9IUr
{ r;&rc:?A
AFX_MANAGE_STATE(AfxGetStaticModuleState()); UR.l*+<W7
hins=AfxGetInstanceHandle(); cH\.-5NQ
InitHotkey(); t[ ^68]
return CWinApp::InitInstance(); OLxiY r
} XhJbBVS|
{3=]cLtt
int CHookApp::ExitInstance() ?e!mv}B_
{ 4P}<86xk
VerifyWindow(); |B.tBt^
UnInit(); 2=xjgK
return CWinApp::ExitInstance(); @phb5
} N;]"_"
Q>emyij
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file &8uq5uKg
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) N!:&Xz
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ }zu?SZH
#if _MSC_VER > 1000 P_ x9:3
#pragma once 3 ]}wZY0
#endif // _MSC_VER > 1000 zHvG3Ed@
elf2!
class CCaptureDlg : public CDialog 7LY4q/
{ -*Z;EA-
// Construction 7ClN-/4
public: 9.qjEe
BOOL bTray; %-eags~sUC
BOOL bRegistered; IH1
fvW
e
BOOL RegisterHotkey(); fPW(hb;
UCHAR cKey; 9My
|G)M6
UCHAR cMask; qkN{l88
void DeleteIcon(); {
'Db
void AddIcon(); (},TZ+u
UINT nCount; )a%kAUNj
void SaveBmp(); SiyZq"
CCaptureDlg(CWnd* pParent = NULL); // standard constructor }&OgI