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:
(fWQ?6[
I~Zm**L 一、实现方法
9L9mi<, *r]#jY4qx 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:
~w RozV Z7R+'OC #pragma data_seg("shareddata")
4'#
_b HHOOK hHook =NULL; //钩子句柄
OKzk\F6 UINT nHookCount =0; //挂接的程序数目
=t-503e.J static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
::kpAE] static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
JTB5#S4W static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
}L*cP;m# static int KeyCount =0;
KHXnB static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
pG:)u
cj #pragma data_seg()
u@zBE?
g -^7n+
QX 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。
uc;QSVWGy8 9Uh nr]J. 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:
Y~M H ]7{-HuQ8>} BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
n7Ia8?8-l cKey,UCHAR cMask)
RpY#_\^hI {
_u`W$EG
L BOOL bAdded=FALSE;
tMy@'nj for(int index=0;index<MAX_KEY;index++){
J&6]3x if(hCallWnd[index]==0){
yf6&'Y{ hCallWnd[index]=hWnd;
\(bML#I HotKey[index]=cKey;
jVu3 !{} HotKeyMask[index]=cMask;
/c 1FFkq|K bAdded=TRUE;
wA}+E)x/C KeyCount++;
.oo>NS break;
Fc<+N0M{ }
hYN b9^ }
ysiBru[u
return bAdded;
oMi"X"C:q }
,!4(B1@
//删除热键
"2bCq]I0 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
,Z I"+v {
"GofQ5,| BOOL bRemoved=FALSE;
8~|PZ,oZ for(int index=0;index<MAX_KEY;index++){
re/l5v,|3 if(hCallWnd[index]==hWnd){
",T-'>h$2R if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
1jozM"H7Q hCallWnd[index]=NULL;
<tg>1,C HotKey[index]=0;
%/&?t`%H HotKeyMask[index]=0;
&6L{1 bRemoved=TRUE;
r 6STc,%5 KeyCount--;
+d736lLe% break;
fhmqO0 }
fm\IQqIK% }
pJ5Sxgv{; }
jM90
gPX>, return bRemoved;
y(8AxsROp }
mko<J0|4 qyuU HIi5kv]}| DLL中的钩子函数如下:
O=St}B\!m OPwj*b:-m LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
3l 0> {
$9\!CPZ2 BOOL bProcessed=FALSE;
;HJ|)PN5L if(HC_ACTION==nCode)
g+k0Fw]! {
v7/qJ9l if((lParam&0xc0000000)==0xc0000000){// 有键松开
e? fFh,a switch(wParam)
~V"D|U;i + {
.~6p/fHX case VK_MENU:
#^v|u3^DD MaskBits&=~ALTBIT;
GRb"jF>ut break;
*eytr#0B- case VK_CONTROL:
[x5T7= MaskBits&=~CTRLBIT;
>LwZ"IEV break;
NQ!jkojD case VK_SHIFT:
q8.K-"f(Q MaskBits&=~SHIFTBIT;
DEL#MD! break;
*#,wV
default: //judge the key and send message
Jx@3zl break;
Nq)=E[$ }
n||/3-HDj for(int index=0;index<MAX_KEY;index++){
_}7N,Cx if(hCallWnd[index]==NULL)
RI"A'/56 continue;
-lm\~VZT3 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
0p_/eWww- {
g~Zel}h# SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
,\f!e#d bProcessed=TRUE;
Qe=!'u.nL }
[=-?n6 }
~fE@]~f> }
_d&FB~= else if((lParam&0xc000ffff)==1){ //有键按下
5TVDt switch(wParam)
C-$S]6 {
1
{dhGX case VK_MENU:
n=n!Hn MaskBits|=ALTBIT;
EOjo>w> break;
k9.2*+vvg case VK_CONTROL:
}}v;V*_V MaskBits|=CTRLBIT;
[|\~-6"7N| break;
8|`4D 'Ln case VK_SHIFT:
qde.;Yv9 MaskBits|=SHIFTBIT;
]z,W1Zs? break;
&<-Sxjj default: //judge the key and send message
%J?;@ G)r break;
|?SK.1pW }
-U(T for(int index=0;index<MAX_KEY;index++){
<Vr" if(hCallWnd[index]==NULL)
|Gb"%5YD continue;
x5k6yHn if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
%^g BDlR^ {
Y0=qn'`. SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
/z*?:* bProcessed=TRUE;
,K8O<Mw8 }
GH![rK }
b:Dr_| }
)W~w72j- if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
# &o3[.)9 for(int index=0;index<MAX_KEY;index++){
Q uy5H if(hCallWnd[index]==NULL)
Kgi%Nd continue;
RiF~-;v& if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
a1Qg&s< SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Tz1St{s\ //lParam的意义可看MSDN中WM_KEYDOWN部分
{mMrD 5 }
T&I*8 R~ }
!j6]k^ra }
NWSBqL5v return CallNextHookEx( hHook, nCode, wParam, lParam );
.
Yg)|/ }
>z1RCQWju O2?ye 4uq 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:
._"U{
f2V ](4V3w. BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
u<./ddC BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
[L8Bgw1 _K>cB<+d 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:
K>9]I97g' 7M<Ae
D% LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
<XX\4[wb {
Sb+pB58&N if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
l)fF)\ |;= {
a%7ju4CVj //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
2:Q9gru SaveBmp();
f7}/ {}g return FALSE;
Z}TuVE }
<P7f\$o~ …… //其它处理及默认处理
&C<B=T"I }
|_8-3 ,2/qQD n/ a1B_w#?8 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。
0n|op:]BHM bN@V=C3 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。
ZkkXITQkPM wX" 6 S: 二、编程步骤
5zX;/n~ /i$E |[ 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";
f2B?Zn F`3c uL[N 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
dX: (%_Mn at${^,& 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;
f@Rn&&- :f?\ mVS+ 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;
mdR:XuRD"t .@ZqCH 5、 添加代码,编译运行程序。
~xpU<Pd* hV])\t=yf 三、程序代码
=O1N*'e ngj=w;7~+ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
k!b\qS~Q #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
Mb=vIk{Bf #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
n;)!N #if _MSC_VER > 1000
snOd
3Bw #pragma once
v-J*PB.0p #endif // _MSC_VER > 1000
So\(]S #ifndef __AFXWIN_H__
Q5b?-
P #error include 'stdafx.h' before including this file for PCH
N&U=5c`Q' #endif
i)g=Lew #include "resource.h" // main symbols
mK5<;$ class CHookApp : public CWinApp
LX'.up11X5 {
\B8tGog public:
nVko]y CHookApp();
pI|Lt // Overrides
uuHR! // ClassWizard generated virtual function overrides
X90VJb] //{{AFX_VIRTUAL(CHookApp)
-z./6dQ public:
o {Sc virtual BOOL InitInstance();
j{SRE1tqh virtual int ExitInstance();
{$)zC*l //}}AFX_VIRTUAL
r5> FU>7' //{{AFX_MSG(CHookApp)
oE[wOq+ // NOTE - the ClassWizard will add and remove member functions here.
p<*3mbgGO // DO NOT EDIT what you see in these blocks of generated code !
-gefdx6ES //}}AFX_MSG
k`U")lv DECLARE_MESSAGE_MAP()
xGCW-YR9 };
3~}G~ t LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
pw"
!iG} BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
hC?:XVt BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
$As;Tvw. BOOL InitHotkey();
`@q[&^ BOOL UnInit();
%>Z^BM<e #endif
l^w=b~|7= -"[o|aa^ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
|}
;&xI #include "stdafx.h"
:2iNw>z1 #include "hook.h"
h`X)sC+ #include <windowsx.h>
X@|'#% #ifdef _DEBUG
2%i_SX[ #define new DEBUG_NEW
eRc+.m[ #undef THIS_FILE
Qyvn A|& static char THIS_FILE[] = __FILE__;
G?CaCleG #endif
q,3_)ZOq #define MAX_KEY 100
A94ZG: #define CTRLBIT 0x04
'=K
[3%U #define ALTBIT 0x02
bhDV U(%I6 #define SHIFTBIT 0x01
Ppi/`X #pragma data_seg("shareddata")
1Y4=D
HHOOK hHook =NULL;
qPGpN0M` UINT nHookCount =0;
>UvLeS2h:y static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
$$ou qLu static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
@^]wT_r static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
9J h"1i>x2 static int KeyCount =0;
j h0``{ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
e\%+~GUTC= #pragma data_seg()
6&_"dg" HINSTANCE hins;
q&OF?z7H void VerifyWindow();
u+%Ca,6 BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
EITA[Ba B` //{{AFX_MSG_MAP(CHookApp)
L)W1bW} // NOTE - the ClassWizard will add and remove mapping macros here.
/|V!2dQs" // DO NOT EDIT what you see in these blocks of generated code!
]Ir{9EE
v //}}AFX_MSG_MAP
ZDuP|" ^ END_MESSAGE_MAP()
5S`_q& XG FjqZr` CHookApp::CHookApp()
oU`8\n]( {
]=\vl>W // TODO: add construction code here,
? 3
{&" // Place all significant initialization in InitInstance
BH6)`0&2*N }
qniP`P4E gsFyZ CHookApp theApp;
Tlc3l}B*Z LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
CZ*#FY {
ap;?[B~Ga BOOL bProcessed=FALSE;
n+1!/H=d if(HC_ACTION==nCode)
Y|JC+Ee {
$BHbnsaQ if((lParam&0xc0000000)==0xc0000000){// Key up
/{@^h#4M1 switch(wParam)
w/_n$hX {
VQ wr8jXye case VK_MENU:
+TzZ
MaskBits&=~ALTBIT;
P7ktr?V0a break;
9D@
$Y54 case VK_CONTROL:
ML@-@BaN MaskBits&=~CTRLBIT;
i4;`dCT|A break;
rP$vZ^/c case VK_SHIFT:
${I$@qq83 MaskBits&=~SHIFTBIT;
@!k\Ivd break;
xuBXOr4"P default: //judge the key and send message
5@l[!Jl0k break;
,Vb;2 }
GZJIIP# for(int index=0;index<MAX_KEY;index++){
Sc!]M 5 if(hCallWnd[index]==NULL)
]gHxvT\E continue;
K5l#dl_T if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
%B9iby8)1 {
#m>Rt~(,S SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
lS1-e0,h1 bProcessed=TRUE;
$7M/rF;N5X }
L(Ww6oj }
O`Ht|@[6 }
CUJP"u>8M else if((lParam&0xc000ffff)==1){ //Key down
eyq\a'tyB switch(wParam)
YbCqZqk {
">pW:apl% case VK_MENU:
BCnf'0q MaskBits|=ALTBIT;
T'YHV}b}vX break;
kg@D?VqJP case VK_CONTROL:
x1H?e8 MaskBits|=CTRLBIT;
~yacJU= break;
: (IPrQ case VK_SHIFT:
]MI>"hn MaskBits|=SHIFTBIT;
&?+ vHE} break;
@L?X}'0xI4 default: //judge the key and send message
X3nt*G1dL break;
?}f+PP, }
F.;G6 for(int index=0;index<MAX_KEY;index++)
QG{).|pm {
Q2^~^'Yk if(hCallWnd[index]==NULL)
YA(_*h
continue;
<(|No3jx if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
z3F ^OU {
dFdll3bC SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
}mGOEG|F2 bProcessed=TRUE;
X`xI~&t_ }
MYVUOd, }
bpe8
`b(# }
7\ .Ax if(!bProcessed){
PT2b^PP for(int index=0;index<MAX_KEY;index++){
>Hh8K<@NL if(hCallWnd[index]==NULL)
E>_?9~8Mf continue;
RX]x3- if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
G` !ff SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
_W@SCV)yH }
7lP3\7wD@9 }
3,`.$
}
,.#
SEv5 return CallNextHookEx( hHook, nCode, wParam, lParam );
iQ[0d.(A }
9C$#A +~C >;E[XG^ BOOL InitHotkey()
qg7]
YT& {
sOyWsXd+R' if(hHook!=NULL){
iz|mJUx nHookCount++;
w1zI"G~4/Q return TRUE;
|.bp }
TmN}TMhZ else
>{DHW1kF? hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
fVR:m`'Iq_ if(hHook!=NULL)
eiLtZQ nHookCount++;
$}[Tj0+: return (hHook!=NULL);
P1PP#>E-2 }
Salu[)+? BOOL UnInit()
[\9WqHs {
xP@VK!sc if(nHookCount>1){
`
eB-C// nHookCount--;
1[k~*QS return TRUE;
m wuFXu/ }
o?G^=0T BOOL unhooked = UnhookWindowsHookEx(hHook);
+B*8$^,V) if(unhooked==TRUE){
>$.u|a nHookCount=0;
MSEBvZ- hHook=NULL;
wu*WA;FnA }
Kuh! b`9 return unhooked;
V/j]UK0$ }
a
S-
rng dEXHd@"H BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Pn{yk`6E {
-KRHcr \ BOOL bAdded=FALSE;
vPG!S{4 for(int index=0;index<MAX_KEY;index++){
?e|'I" if(hCallWnd[index]==0){
rT`D@
I hCallWnd[index]=hWnd;
#vO3*-hs HotKey[index]=cKey;
&`7~vA&c HotKeyMask[index]=cMask;
':,6s bAdded=TRUE;
)k&pp^q\ KeyCount++;
ujcS>XN,1 break;
`92 D]^g }
ArkFC }
c%.f|/.k
return bAdded;
-_jV.`t }
inBd.%Yr H*QN/{|RU BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
~qNpPIrGr {
R|Ft@]
BOOL bRemoved=FALSE;
oeXNb4; 4 for(int index=0;index<MAX_KEY;index++){
>J=x";,D|~ if(hCallWnd[index]==hWnd){
YtQKsM if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
FV/xp}nz hCallWnd[index]=NULL;
T0_9:I`& HotKey[index]=0;
wAHb5>! HotKeyMask[index]=0;
syh0E=If_ bRemoved=TRUE;
|-7<?aw" KeyCount--;
GS{:7%=j break;
AK<ZP?0 }
x7e }
D} 0>x~ }
:C42yQAP return bRemoved;
&Q