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(I^:_eH
%w^*7Oi 一、实现方法
/C8 }5) iQ" LIeD 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:
3g4=as4w fJr
EDj4( #pragma data_seg("shareddata")
;\w3IAa|V HHOOK hHook =NULL; //钩子句柄
b+a+OI D UINT nHookCount =0; //挂接的程序数目
k{mBG9[z static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
3*I\#Z4p1 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
^gcB+ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
5)< Y3nU~ static int KeyCount =0;
xF{%@t static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
_h<rVcl!wX #pragma data_seg()
KNmU2-%l T^;b98* 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。
#8h7C8]& _ ]5UuIMl 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:
PR"x&JG@ fof}I:vO BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
Y#c439 & cKey,UCHAR cMask)
MtL<)?HQ {
%j^QK>% BOOL bAdded=FALSE;
@K!JE w\ for(int index=0;index<MAX_KEY;index++){
pG"wQ if(hCallWnd[index]==0){
nT> v hCallWnd[index]=hWnd;
ke2dQ^kc4 HotKey[index]=cKey;
9xbT?$^ HotKeyMask[index]=cMask;
xy:Mb =r bAdded=TRUE;
FQ0&{ulb KeyCount++;
A4,%l\di< break;
BlpyE[h
T }
JE}VRMNr }
5,,'hAq_ return bAdded;
!@lx|=# }
a!bW^?PcK //删除热键
6MM\nIU)/ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
BR|0uJ.M {
].rKfv: BOOL bRemoved=FALSE;
5 <k)tF% for(int index=0;index<MAX_KEY;index++){
w\i]z1 if(hCallWnd[index]==hWnd){
U3_ O}X+ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
*eHa4I hCallWnd[index]=NULL;
rSv,;v HotKey[index]=0;
*DIY;)K HotKeyMask[index]=0;
*=oO3c0|b, bRemoved=TRUE;
4AEw[(t KeyCount--;
'GezIIaH break;
Jd/d\P }
$B?8\>_? }
Ee MKo }
=7e!'cF[ return bRemoved;
Z e>R@rK }
P Ptmh. }e |a03SZx Lp-$Ie DLL中的钩子函数如下:
&ic'!h" 3ux7^au LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
d 8;kM`U {
itNuY<" BOOL bProcessed=FALSE;
Fk49~z if(HC_ACTION==nCode)
cEa8l~GC< {
Fy\q>(v. if((lParam&0xc0000000)==0xc0000000){// 有键松开
n@tt.n!{l switch(wParam)
xGyl7$J {
*bo| F%NAz case VK_MENU:
+pgHCzwJE MaskBits&=~ALTBIT;
^[SW07o~ break;
aPlEM_escS case VK_CONTROL:
uxn+.fA MaskBits&=~CTRLBIT;
mC@v," break;
H0&wn#);6R case VK_SHIFT:
*~GI-h MaskBits&=~SHIFTBIT;
:ILpf+`yY break;
f|(9+~K/7& default: //judge the key and send message
Il4]1d| break;
MOh&1]2j5 }
9b >+ehj B for(int index=0;index<MAX_KEY;index++){
4z P"h0 if(hCallWnd[index]==NULL)
mfg>69,w continue;
Fc[vs52 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
P !f{U;B {
\mLEwNhRY SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
`W}pAmhj bProcessed=TRUE;
?ch?q~e) }
oU,8?(}'~ }
9O&m7]3 }
z*.G0DFw else if((lParam&0xc000ffff)==1){ //有键按下
423%K$710 switch(wParam)
cvy
5|;-u {
LhKbZoPp case VK_MENU:
q !9;JrX MaskBits|=ALTBIT;
00D.Jn break;
;bG?R0a case VK_CONTROL:
jMBMqQNU MaskBits|=CTRLBIT;
?J+jv break;
#Pk{emYW case VK_SHIFT:
JAKs [@: MaskBits|=SHIFTBIT;
3mofp`e break;
/-!Fr:Ox> default: //judge the key and send message
l8(9?!C
break;
#Tzs9Bkaca }
p #w8$Qjp for(int index=0;index<MAX_KEY;index++){
u9Adu` if(hCallWnd[index]==NULL)
@ NDcO,] continue;
h-Y>>l>PW0 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
~D5FnN9 {
]:@{tX7c SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
6X9$T11Vc bProcessed=TRUE;
An#[
+? }
Y?1T
XsvF }
uSYI
X }
Y*pXbztP if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
V?*fl^f for(int index=0;index<MAX_KEY;index++){
b=BNbmX if(hCallWnd[index]==NULL)
8J&9}@y continue;
z[ ;n2o|s if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
+C;;4s) SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
[4C_iaE //lParam的意义可看MSDN中WM_KEYDOWN部分
2k=|p@V n~ }
%pWJ2J@ }
}R}M>^(R4 }
>0:3CpO* return CallNextHookEx( hHook, nCode, wParam, lParam );
O[$X36z }
?glx8@ N:Q.6_%^ 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:
`L$Av9X\ QZ(O2!Mg BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
~sn3_6{ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
NG3:= >A]l|#Rz 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
:j3^p8] J
?aJa LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
> .}G[C {
X}
V]3 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
~0024B[G {
mpD.x5jm< //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
h`! 4`eI SaveBmp();
K)x6F15r return FALSE;
nm\f$K>Pg }
q("l?' …… //其它处理及默认处理
Am3j:|>* }
f%_$RdU Z%ZOAu&p )CoFRqz<h 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
dk1q9Tx nTsV>lQY, 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
WxD$k3U `0W"[BY 二、编程步骤
`lm '_~=`& Y:+:>[F 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";
%r6_['T D->E& # 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
fh_:ung H/[(T%]o 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;
1Zk1!> ? N1g;e?T': 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;
k}kwr[ wp8-(E^ 5、 添加代码,编译运行程序。
VIGLl'8p =&-.] |t 三、程序代码
aVVE2:M gjK: a@{ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
tculG|/ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
s$9ow<oi] #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
sX>|Y3S\U #if _MSC_VER > 1000
yTbtS- #pragma once
K; hP0J #endif // _MSC_VER > 1000
}Dcpe M? #ifndef __AFXWIN_H__
OmK0-fa/ #error include 'stdafx.h' before including this file for PCH
O*/Utl #endif
Tf$> ^L #include "resource.h" // main symbols
/L$q8 + class CHookApp : public CWinApp
3- d"-'k {
R(y`dQy<K public:
nx`W!|g$` CHookApp();
lr)MySsu#H // Overrides
<.lN'i;( // ClassWizard generated virtual function overrides
t':*~b{V@7 //{{AFX_VIRTUAL(CHookApp)
70*yx?T V public:
&SZAe/3+ virtual BOOL InitInstance();
"lA$;\& virtual int ExitInstance();
YP"%z6N@v //}}AFX_VIRTUAL
#/`MYh=!W //{{AFX_MSG(CHookApp)
{az
LtTh // NOTE - the ClassWizard will add and remove member functions here.
OB(~zUe.R // DO NOT EDIT what you see in these blocks of generated code !
DVs$3RL //}}AFX_MSG
?|2m0~%V= DECLARE_MESSAGE_MAP()
yYk?K<ou };
T8T,G4Q LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
6xh-m BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
XxB% BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
(|6!pQ7 BOOL InitHotkey();
7S&O{Q7) BOOL UnInit();
v"sU87+ #endif
MS|1Q@S9 s5d[sx //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
tUfze9m #include "stdafx.h"
odcrP\S #include "hook.h"
8fWnKWbbjw #include <windowsx.h>
blbzh';0} #ifdef _DEBUG
pek5P4W_ #define new DEBUG_NEW
kc2E4i #undef THIS_FILE
8p~[8} static char THIS_FILE[] = __FILE__;
tnmz5Q #endif
?
zic1i #define MAX_KEY 100
y(K:,CI #define CTRLBIT 0x04
b$Bq#vdg: #define ALTBIT 0x02
5oD%~Fk l #define SHIFTBIT 0x01
P!~&Ei #pragma data_seg("shareddata")
[nsTO5G$u HHOOK hHook =NULL;
[S`Fm>, UINT nHookCount =0;
#zd}xla0] static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
*i7-_pT static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
V3pn@'pr static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
=8qhK=&] static int KeyCount =0;
=PBJ+"DQs static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
^dhtc%
W> #pragma data_seg()
\w{fq+G HINSTANCE hins;
=)6|lz^ void VerifyWindow();
BxxqzN+ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
t9
id^ //{{AFX_MSG_MAP(CHookApp)
{K=[Fu= // NOTE - the ClassWizard will add and remove mapping macros here.
{}PBYXR // DO NOT EDIT what you see in these blocks of generated code!
DGAg#jh //}}AFX_MSG_MAP
ORV'dr END_MESSAGE_MAP()
q*>|EJR^Rw A56aOI= CHookApp::CHookApp()
xaSiG {
oP<E) // TODO: add construction code here,
eY$Q}BcW // Place all significant initialization in InitInstance
0ipYXbC }
^yF2xJ)9- f=MR.\ CHookApp theApp;
!3at(+4 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Lr(wS { {
KI<Vvcm BOOL bProcessed=FALSE;
BtWm ZaKi if(HC_ACTION==nCode)
j\@|oW0 {
~hA;ji|I if((lParam&0xc0000000)==0xc0000000){// Key up
oakm{I|k} switch(wParam)
L@5g#mSl {
\?.M1a[ case VK_MENU:
o{QPW MaskBits&=~ALTBIT;
!}uev break;
;,_c1x/F case VK_CONTROL:
J
9k~cz MaskBits&=~CTRLBIT;
9_S>G$9D break;
|a Ht6F case VK_SHIFT:
*8QGv6*vQ MaskBits&=~SHIFTBIT;
8[z& g%u break;
,7Lu7Q default: //judge the key and send message
QVrMrm+vRv break;
MU&P+Wr }
rU1{a" { for(int index=0;index<MAX_KEY;index++){
$y*["~TJ if(hCallWnd[index]==NULL)
5/{gY{ continue;
%g&i.2v if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
-@_V|C'? {
AJH-V
6 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
ep"54o5=d bProcessed=TRUE;
9Lxj
]W2^ }
q^w3n2 }
NCysYmt }
Ijj]_V{, else if((lParam&0xc000ffff)==1){ //Key down
9Ic~F^ switch(wParam)
vN4g#,< {
s*j0uAq)up case VK_MENU:
M%2F7 FY MaskBits|=ALTBIT;
.@ElfPP(L break;
#G ZGk? case VK_CONTROL:
APksY! MaskBits|=CTRLBIT;
&ExYul break;
! Q5ip'L case VK_SHIFT:
`#~HCl MaskBits|=SHIFTBIT;
q[SUYb;, break;
sj @'C@oK default: //judge the key and send message
:3Z"Qk$uR break;
fOyLBixR }
m<;&B for(int index=0;index<MAX_KEY;index++)
sf5koe {
az]S&\i7T if(hCallWnd[index]==NULL)
IZ6[|Ach6 continue;
+H
L]t'UEg if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
;0 VE* {
UujFZg[-P9 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
NN W* bProcessed=TRUE;
OC]_b36v }
6!n%SUt }
b1;80P/:D }
^4yFLqrC if(!bProcessed){
[
Q6v #I for(int index=0;index<MAX_KEY;index++){
(HkMubnqg if(hCallWnd[index]==NULL)
A%s"WSx, continue;
vx_v/pD if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
>p 7e6% SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
RSY{IY }
cwxO|
.m }
G =+ sW }
i=<N4Vx return CallNextHookEx( hHook, nCode, wParam, lParam );
b&Sk./
J6 }
bg)yliX 9c1n BOOL InitHotkey()
DP NUm<> {
q*<Df=+B if(hHook!=NULL){
t$Z#zxX nHookCount++;
!f\y3p*j return TRUE;
E0}jEl/{ }
bd2"k;H<o else
`1KZ14K hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
;o#R(m@Lx if(hHook!=NULL)
eRa1eRgP nHookCount++;
'7{0k{ return (hHook!=NULL);
!R WX1Z }
yl%F}kBR BOOL UnInit()
56m|gZcC {
$vdGkz@6 if(nHookCount>1){
Z;W`deA nHookCount--;
fmvv
q1G& return TRUE;
'+|{4-V }
m(8t |~S BOOL unhooked = UnhookWindowsHookEx(hHook);
@fbB3 if(unhooked==TRUE){
H0s,tTK8 nHookCount=0;
g!O(@Sqp1 hHook=NULL;
m4*Rr }
cV5Lp4wY? return unhooked;
@qH<4`y.^ }
c)M_&?J!5 -~
`5kO~ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
2Fce| Tn {
It4J\S BOOL bAdded=FALSE;
Kl$!_ $ for(int index=0;index<MAX_KEY;index++){
s"G6aM if(hCallWnd[index]==0){
^=wG#!#V"1 hCallWnd[index]=hWnd;
~OEP)c\k HotKey[index]=cKey;
g0^%X9s HotKeyMask[index]=cMask;
G)?O!(_ bAdded=TRUE;
0QDm3V0n KeyCount++;
J%;TK6 break;
R)#D{/#FW }
XWbe|K!e }
/cr.}D2O return bAdded;
g R(*lXm5w }
M,PZ|=V6a BjJ$I^ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
t.>vLzrU {
>'8.>f BOOL bRemoved=FALSE;
1DGVAIcD for(int index=0;index<MAX_KEY;index++){
~/hP6* if(hCallWnd[index]==hWnd){
-X
Bh\w if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
7k:}9M~ hCallWnd[index]=NULL;
?PSm)
~Oa HotKey[index]=0;
rBkf @ HotKeyMask[index]=0;
Q4Q*5> bRemoved=TRUE;
'j!7
O+7y KeyCount--;
6pQ#Zg()vp break;
^[8e|,U }
^ow[XEB% }
X{ZBS^M }
>GgX-SZ% return bRemoved;
abCcZ<=|b }
?4_^}B9 |jaUVE_2[ void VerifyWindow()
&|26x
> {
U\
y?P:yy for(int i=0;i<MAX_KEY;i++){
Om{[ <tL if(hCallWnd
!=NULL){ >wM%|j'
if(!IsWindow(hCallWnd)){ +8Zt<snG
hCallWnd=NULL; q=}Lm;r
HotKey=0; ALwkX"AN
HotKeyMask=0; *n2Q_o
KeyCount--; yIbz\3
} M0 x5s@
} o
1#XM/Z
} sN7I~
} _4rb7"b1
L;5jhVy
BOOL CHookApp::InitInstance() co<){5zOT
{ T8ZBQ;o
AFX_MANAGE_STATE(AfxGetStaticModuleState()); FymA_Eq
hins=AfxGetInstanceHandle(); OgS6#X
InitHotkey(); qw0tw2|
return CWinApp::InitInstance(); z(>{"t<C
} #v')iR"
{`KgyCW:
int CHookApp::ExitInstance() =6j
5,
{ 91%+Bf()J6
VerifyWindow(); q[1H=+
UnInit(); 1U~AupHE
return CWinApp::ExitInstance(); -Z<e`iFQS
} n@5pS3qZ
brNe13d3~"
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file V@84Cb
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) usR19 _E-
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ sxO_K^eD
#if _MSC_VER > 1000 r NqJL_!
#pragma once WMZa6cH
#endif // _MSC_VER > 1000 HQaKG4Z
[lQp4xgxi
class CCaptureDlg : public CDialog ,ye>D='
{ %g0"Kj5
// Construction HHCsWe-
public: Fx0K.Q2Y0
BOOL bTray; 8b(UqyV
BOOL bRegistered; ;MCv
BOOL RegisterHotkey(); dj?.Hc7od
UCHAR cKey; u-pE
;|
UCHAR cMask; A86#7
void DeleteIcon(); |>A1J:
void AddIcon(); u$&