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:
Amp#GR1CA
,%6P0#- 一、实现方法
)5rb&M} %fc!2E9| 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:
tankR9(o }bs+-K #pragma data_seg("shareddata")
Bz^jw>1b HHOOK hHook =NULL; //钩子句柄
O $LfuL UINT nHookCount =0; //挂接的程序数目
>c1!p]&V static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
*7:>EP static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
s0\X ^ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
-]L6= static int KeyCount =0;
:C7_Jp*Qv static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
grS:j+_M2m #pragma data_seg()
j -0z5|*KE 81](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。
U GD2
2-&k^Gl!: 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:
\@WDV "
f
<Z=c BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
:Uz| 3gq cKey,UCHAR cMask)
wZG\>9~ {
DD7h^-x BOOL bAdded=FALSE;
T,7Y7c/3V for(int index=0;index<MAX_KEY;index++){
+?F[/?s5qz if(hCallWnd[index]==0){
, qA(\[ hCallWnd[index]=hWnd;
u&1q [0y HotKey[index]=cKey;
4^:\0UF HotKeyMask[index]=cMask;
qUh2hz: bAdded=TRUE;
3%l*N&gsg: KeyCount++;
hwu]Er.gn break;
0f~C#/[t7 }
d^Inb!%w }
C^3 <={ return bAdded;
MV<^!W }
N+++4; //删除热键
dUsYZdQs BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
E4xj?m^(y= {
?u-|>N> BOOL bRemoved=FALSE;
1jCLO} for(int index=0;index<MAX_KEY;index++){
vo`2\R. if(hCallWnd[index]==hWnd){
uH/J]zKR if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
i;]"n;>+/ hCallWnd[index]=NULL;
E;,u2[3 HotKey[index]=0;
Z LB4m` HotKeyMask[index]=0;
N2B|SO'' bRemoved=TRUE;
T~--92[ KeyCount--;
L\Aq6q@c break;
Y?S!8-z }
`2' #!- }
BZ:H`M`n }
+s(HOq)b return bRemoved;
<d,b '<z
s }
&{ay=Mj !HrKXy0{ M1 :uJkO. DLL中的钩子函数如下:
kv3E4,<9 l H#u LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
>[MX:Yh {
?h.wK BOOL bProcessed=FALSE;
$@"l#vJPfc if(HC_ACTION==nCode)
cimp/n" {
\!>3SKs(e if((lParam&0xc0000000)==0xc0000000){// 有键松开
IT(lF switch(wParam)
/~}}"zx& {
'3_]Gu-D case VK_MENU:
U[SaY0Z MaskBits&=~ALTBIT;
oz AS[B6 break;
cJN7bA{ case VK_CONTROL:
txW{7[w+, MaskBits&=~CTRLBIT;
W=vG$ break;
xgbJ2Mh case VK_SHIFT:
{ D^{[I MaskBits&=~SHIFTBIT;
^c<ucv6. break;
;-9=RI0 default: //judge the key and send message
UmNa[s break;
1xD=ffM>8N }
cVubb}ou for(int index=0;index<MAX_KEY;index++){
3x5JFM if(hCallWnd[index]==NULL)
?kWC}k{ continue;
y&Mr=5:y if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
ZNf6;%oGG {
KB%"bqB| SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
n1JRDw"e$$ bProcessed=TRUE;
M*z~gOZ }
`dFq:8v }
>ZPsjQuf" }
FuVnk~gq else if((lParam&0xc000ffff)==1){ //有键按下
[<- switch(wParam)
L$9.8W {
!_`&Wks case VK_MENU:
2Or'c`| MaskBits|=ALTBIT;
|zR8rqBX; break;
{XNREjhm case VK_CONTROL:
3^R&:|, MaskBits|=CTRLBIT;
p<zSJLN break;
Y,WuBH case VK_SHIFT:
>_o} MaskBits|=SHIFTBIT;
e<=cdze break;
~;1l9^N| default: //judge the key and send message
P/c&@_b break;
lLp^Gt^}w( }
7N-w eX for(int index=0;index<MAX_KEY;index++){
'qjeXqGH$ if(hCallWnd[index]==NULL)
(IC]?n} continue;
{U!8|( if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
R#2 t)y {
qp/v^$EA SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
\]=7!RQ\ bProcessed=TRUE;
FO!]P }
*"D3E7AO }
KHgBo}6 }
l7W 6qNB if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
y$@ZN~8 for(int index=0;index<MAX_KEY;index++){
%F!1 if(hCallWnd[index]==NULL)
U4gF(Q continue;
odPL{XFj if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
9:,V5n= SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
V>ieh2G( //lParam的意义可看MSDN中WM_KEYDOWN部分
+)j$|x~(A }
5#> 8MU?& }
{P{bOe }
I
6<*X return CallNextHookEx( hHook, nCode, wParam, lParam );
)6+eNsxMlC }
L1ieaKw 2C/$Ei^t 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
<(-3_s6- jJuW-(/4[ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
T-5nB>) BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
D&}3$ 7> cJ1#ge%4 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:
:|Ad:fEs um4yF*3b9 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
2'_:S@ {
!eEHmRgg4 if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
7qj9&bEy {
)=AHf?hn //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
&e;=cAXG SaveBmp();
PNaay:a| return FALSE;
LM7$}#$R }
^j". …… //其它处理及默认处理
} p&&_? }
tZ^Ou89:rG 1E73i_L cfcim.jB 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。
GlbySD@ Q\cjPc0y 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。
\|E^v6E%0 7VMvF/ap]u 二、编程步骤
e pU: \8<BLmf4U 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";
zipS
]YD NX|v= 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
B>GE9y5 iMs5zf<M 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;
du)~kU>l Dh5X/y 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;
[P 06lIO |1b_3?e 5、 添加代码,编译运行程序。
2I&o69x? SQqD:{#g" 三、程序代码
PB#fP_0C 6xZ=^;H ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
91$]Qg,lB #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
:_t}QP" #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
i K12pw #if _MSC_VER > 1000
:cGt#d6 #pragma once
cG?cUw).E #endif // _MSC_VER > 1000
rMU T_^ #ifndef __AFXWIN_H__
co9 .wB@ #error include 'stdafx.h' before including this file for PCH
x\J#]d. #endif
d)pV;6%[$q #include "resource.h" // main symbols
OtGb<v<_H class CHookApp : public CWinApp
'JNElXqrv {
>2]JXLq public:
>lBD<;T CHookApp();
fH)YFn/ // Overrides
3bDQk
:L // ClassWizard generated virtual function overrides
:PtF+{N> //{{AFX_VIRTUAL(CHookApp)
Clh!gpB c public:
|i ZfYi&^ virtual BOOL InitInstance();
O9g{+e` virtual int ExitInstance();
`&-Mi[1 //}}AFX_VIRTUAL
7DIIx}A //{{AFX_MSG(CHookApp)
F$^Su<w5l // NOTE - the ClassWizard will add and remove member functions here.
e0J6Ae4V[ // DO NOT EDIT what you see in these blocks of generated code !
kI:}| _ //}}AFX_MSG
%/YcL6o( DECLARE_MESSAGE_MAP()
bks/`rIA };
Op>%?W8/UF LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
1}tbH[ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
G 2mX; BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
jq+A-T}@ BOOL InitHotkey();
1!.(4gV BOOL UnInit();
F35#dIs`& #endif
(sQr X{~ %zSuK8kxV //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
z^GDJddG #include "stdafx.h"
_z54Ycr4H #include "hook.h"
y|Ir._bt #include <windowsx.h>
z8[yt282 #ifdef _DEBUG
zcva-ze:; #define new DEBUG_NEW
g7&9" #undef THIS_FILE
8P"_#M?! static char THIS_FILE[] = __FILE__;
}sx_Yj #endif
=L C:SFzF #define MAX_KEY 100
m\ddp_l #define CTRLBIT 0x04
%/>Y/!; #define ALTBIT 0x02
U-:ieao@ #define SHIFTBIT 0x01
Z*])6=2Q #pragma data_seg("shareddata")
?_ dIIQ HHOOK hHook =NULL;
cetvQAGXY UINT nHookCount =0;
on8WQf'A# static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
l/Vo-# static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
8o/}}=m$ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
r%e KFS static int KeyCount =0;
~u.T- 0F static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
Y2O"]phi@ #pragma data_seg()
,:%"-`a% HINSTANCE hins;
cW{1
Pz^_ void VerifyWindow();
e5OsIVtjr BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
CT\;xt,S //{{AFX_MSG_MAP(CHookApp)
JICawj:I // NOTE - the ClassWizard will add and remove mapping macros here.
~`D|IWMDq // DO NOT EDIT what you see in these blocks of generated code!
m~>Y{F2 //}}AFX_MSG_MAP
&
u!\<\ END_MESSAGE_MAP()
PC qZNBN 7c;9$j CHookApp::CHookApp()
^+
wD43 {
/5#rADOS // TODO: add construction code here,
iA,kX\nK // Place all significant initialization in InitInstance
Qjnd6uv{I }
&bhq`> ^{\<N()R CHookApp theApp;
5P .qXA"D LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
dVQ-k {
gZEi]/8_ BOOL bProcessed=FALSE;
!bC+TYsU if(HC_ACTION==nCode)
kvh&d| {
/1 RAAa if((lParam&0xc0000000)==0xc0000000){// Key up
1RKW2RCaW_ switch(wParam)
} %'bullT {
)I\=BPo|B case VK_MENU:
a"av#Y MaskBits&=~ALTBIT;
;r/;m\V break;
jt@SZI` case VK_CONTROL:
](B@5-^ MaskBits&=~CTRLBIT;
#UtFD^h break;
1.D-FPK case VK_SHIFT:
Q`#4W3-, MaskBits&=~SHIFTBIT;
!6G?zipB break;
J>^\oAgpE default: //judge the key and send message
9=,uq; break;
g}f9dB,F }
xBFJ} v for(int index=0;index<MAX_KEY;index++){
63!rUB!
if(hCallWnd[index]==NULL)
Fxc)}i` continue;
,+;:3gRk9 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
f/kI|Z {
lc6iKFyG SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
7n o5b]
\ bProcessed=TRUE;
WU4U Zpz }
n}mR~YqD }
<}jPXEB" }
`mH %!{P else if((lParam&0xc000ffff)==1){ //Key down
L'i-fM[# switch(wParam)
J4=_w {
3u>8\|8wz case VK_MENU:
AOp/d(vx5i MaskBits|=ALTBIT;
WhBpv(q}. break;
^+SkCO case VK_CONTROL:
#,(sAj MaskBits|=CTRLBIT;
<?0~1o\Ur break;
,uz ]V1 case VK_SHIFT:
}<jb vCeK MaskBits|=SHIFTBIT;
NDO\B,7 break;
I =Wc&1g default: //judge the key and send message
^O^:$nXhYy break;
'<iK*[NW }
>\<*4J$PZ for(int index=0;index<MAX_KEY;index++)
Y`6rEA0 {
i77GE if(hCallWnd[index]==NULL)
S<nq8Ebmw continue;
^")F7`PF if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
fU2qrcVu {
Ovw[b2ii SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
6
fz} bProcessed=TRUE;
utlpY1#q/ }
?y XAu0 }
+~nzii3 }
ExHAY|UA if(!bProcessed){
uqyB5V0gh for(int index=0;index<MAX_KEY;index++){
KyP)Qzp if(hCallWnd[index]==NULL)
9H]_4?aX continue;
aH_6s4+: if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
qIwV q!= SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
~F,
&GH }
.wrL3z_ }
%ICglF R }
^4v*W;Q return CallNextHookEx( hHook, nCode, wParam, lParam );
{}>n{_ }
t@?u ?lCd{14Mkh BOOL InitHotkey()
%qsvtc` {
9O,,m~B if(hHook!=NULL){
ALd;$fd qf nHookCount++;
;%q39U} return TRUE;
o[6y+ <'o }
(3,.3)%` else
j%Y\A~DV hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
Ja^ 5?Ar| if(hHook!=NULL)
&217l2X
/ nHookCount++;
-dTLunv return (hHook!=NULL);
E^ h=!RW{ }
$<?X7n^ BOOL UnInit()
K%KZO`gO {
":?T%v> if(nHookCount>1){
%NHYW\sKX nHookCount--;
yfjXqn[Z4 return TRUE;
r@)A
k }
q<=:
>? BOOL unhooked = UnhookWindowsHookEx(hHook);
R
-elIp if(unhooked==TRUE){
Ln#a<Rx.E7 nHookCount=0;
GSVdb/+ hHook=NULL;
FJM;X-UOY }
*ftC_v@p5 return unhooked;
XbvDi+R2A }
2O""4_G 3-wD^4)O, BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
q@#BPu"\l {
+S { BOOL bAdded=FALSE;
W 5DbFSgB for(int index=0;index<MAX_KEY;index++){
uVU`tDzd: if(hCallWnd[index]==0){
-
HOnB= hCallWnd[index]=hWnd;
R e:T9K'e HotKey[index]=cKey;
89eq[ |G_ HotKeyMask[index]=cMask;
e 3@x*XI bAdded=TRUE;
6!7Pm>ml KeyCount++;
{/M\Q@j break;
'
lo.h"" }
x(r+P9f\< }
p%RUHN3G[ return bAdded;
pz}mF D&[ }
w{7ji} JAb$M{t BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
{K.rl%_|N {
T[Q"}&bB BOOL bRemoved=FALSE;
WVL#s?=g for(int index=0;index<MAX_KEY;index++){
}ymvC if(hCallWnd[index]==hWnd){
P\B3
y+) if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
#3.)H9
hCallWnd[index]=NULL;
a?<?5 HotKey[index]=0;
03E3cp" HotKeyMask[index]=0;
Kmry=`=A bRemoved=TRUE;
#vnT&FN0[ KeyCount--;
1$["79k break;
[yd6gH }
&6"P7X }
GgdlVi 2 }
KRk~w] return bRemoved;
<?|6*2_= }
%-^}45](q p?Sl}A@` void VerifyWindow()
0$Ff#8 {
K\sbt7~ for(int i=0;i<MAX_KEY;i++){
F.KrZ3%4iB if(hCallWnd
!=NULL){ m "]!I~jd
if(!IsWindow(hCallWnd)){ mU]s7` %<>
hCallWnd=NULL; 6&],WGz
HotKey=0; xii$e
HotKeyMask=0; {E~l>Z88
KeyCount--; ?M"HXu
} 8t``NZ[
} \!PV*%P
} @&:VKpu\
} R~c1)[[E
TzY!D*%z
BOOL CHookApp::InitInstance() Y\8+}g;KR
{ C"No5r'K3
AFX_MANAGE_STATE(AfxGetStaticModuleState()); <JH9StGGc?
hins=AfxGetInstanceHandle(); V_M@g;<o
InitHotkey(); u%aFb*
return CWinApp::InitInstance(); hT=f;6$
} (w2(qT&