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:
r:Rk!z*
jQrw^6C 一、实现方法
8xN+LL'T{ ]:r6 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:
rGb<7b% tDIQ= #pragma data_seg("shareddata")
d/Y#oVI HHOOK hHook =NULL; //钩子句柄
wmnh7'|0u UINT nHookCount =0; //挂接的程序数目
MGE8S$Z static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
QNesiV0MI static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
.-HwT3 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
- HiRXB static int KeyCount =0;
8Xjp5 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
2\J-7o=P #pragma data_seg()
$|%BaEyk r>ca17 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
-oR P ZtW R /0zB DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
ZF~@a+o ,37\8y?o\ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
N- :.z]j#_ cKey,UCHAR cMask)
S{#L7S {
K]c\3[vR BOOL bAdded=FALSE;
8*Ke;X~N for(int index=0;index<MAX_KEY;index++){
|g,99YIv> if(hCallWnd[index]==0){
Js}1_K hCallWnd[index]=hWnd;
OT{cP3;0*o HotKey[index]=cKey;
!ZrU@T HotKeyMask[index]=cMask;
R7ze~[oF bAdded=TRUE;
J_rb3 KeyCount++;
I$HO[Z! break;
g?i0WS }
"9bd;Tt: }
vkE a[7 return bAdded;
]<Kkq! }
"';K$&,[ //删除热键
GLtd6; V BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
SA[wFc {
iw\yVd^]:k BOOL bRemoved=FALSE;
'K*. ?M for(int index=0;index<MAX_KEY;index++){
ykat0iqo if(hCallWnd[index]==hWnd){
;Qq<5I"y if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
m;@8z[
^5 hCallWnd[index]=NULL;
f1,VbuS9I HotKey[index]=0;
BOdd~f%&tn HotKeyMask[index]=0;
OD;F{Hc bRemoved=TRUE;
{DWL 5V#M KeyCount--;
[Lal_}m? break;
33z^Q`MTC }
IB\O[R$x }
}NpN<C+ }
wlsq[xP return bRemoved;
0 n}2D7 }
,y}@I" *r(Qy0( {U"=}j( DLL中的钩子函数如下:
d`9ofw~3= z,xGjSP LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
yB2}[1 {
WiiAIv& BOOL bProcessed=FALSE;
IC6r? if(HC_ACTION==nCode)
+*L<"@ {
k$3Iv"gbx if((lParam&0xc0000000)==0xc0000000){// 有键松开
Cm%|hk>fQ switch(wParam)
,4--3 MU {
GW,RE\Q: case VK_MENU:
<\`qRz0/ MaskBits&=~ALTBIT;
"el}9OitC break;
~1:_wni case VK_CONTROL:
Xb2.t^
]f MaskBits&=~CTRLBIT;
7.FD16 break;
_?v&\j case VK_SHIFT:
!q!5D` MaskBits&=~SHIFTBIT;
h,|. qfUk break;
7A"v:e default: //judge the key and send message
z9Nial`p break;
<%?!3 n* }
c"lblt5 for(int index=0;index<MAX_KEY;index++){
QERj`/g if(hCallWnd[index]==NULL)
w:aV2 continue;
A9Icn>3?`( if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
F[KM0t! {
`G:I|=#w SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
*aW:Z6N bProcessed=TRUE;
QWwdtk }
)|wC 1J!L }
$O_{cSKg7 }
ftxy]NLF else if((lParam&0xc000ffff)==1){ //有键按下
9";qR, switch(wParam)
21[=xboU {
7sq15oL case VK_MENU:
z-N
N(G+ MaskBits|=ALTBIT;
>!MRk[@
V- break;
xSrjN case VK_CONTROL:
7:e5l19 uI MaskBits|=CTRLBIT;
Y_nl9}&+C0 break;
GB4^ 4Ajx case VK_SHIFT:
sA2esA@C<o MaskBits|=SHIFTBIT;
W:>XXUU break;
yT|44
D2j default: //judge the key and send message
N qS]dH61 break;
r;_*.|AH }
GBY{O2!3u for(int index=0;index<MAX_KEY;index++){
w8cbhc if(hCallWnd[index]==NULL)
089v;
d 6 continue;
mO2u9?N if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
_%G;^ b {
~S\8 ' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
5a&BgBO1M bProcessed=TRUE;
zl<D"eP }
pi5DDK }
[<WoXS1LX }
[ J4n% if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
CsEU:v for(int index=0;index<MAX_KEY;index++){
A|YiSwyy if(hCallWnd[index]==NULL)
_*ar\A` continue;
XhUVDmeUMb if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
XtqhK"f% SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
,\T7{=ZG\! //lParam的意义可看MSDN中WM_KEYDOWN部分
A1n4R }
_+,>NJ }
i0F6eqe=J }
Qs ysy return CallNextHookEx( hHook, nCode, wParam, lParam );
j'`-3<k }
KW!+Ws g@Pq< 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
Y`."=8R~ P9W?sPnC5 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
t;`ULp~& BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
/ke[nr Z7> Nd$E{ 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:
Pkv+^[(4 a4n5i.; LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
Ibg~.>.u{ {
8jY<S+[o if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
L+~XW'P? {
oqo7Ge2 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
jq%}=-%KE SaveBmp();
tz5\O} return FALSE;
a7!{`fR5 }
L;WFHIE …… //其它处理及默认处理
0BH-kr }
(/FG#D. ZW4$Ks2]Y h>F"GR?U_( 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
q4v:s 5O;D\M{> 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
l#~pK6@W R90#T6^ 二、编程步骤
V|~o`(] U>sEFzBup 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
eD8e0
D'S gVrfZ&XF84 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
!hjF"Pa rZWs-]s6t 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
Ckc5;:b&m kj6H+@
{ 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
#lO ^PK [=",R&uD$ 5、 添加代码,编译运行程序。
`Tei C80< L5\ 三、程序代码
b
+Z/nfS Ahc9HA2 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
;2$0j1> #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
5WvsS(
9H #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
)7p(htCz5 #if _MSC_VER > 1000
^#IE
t# #pragma once
Wt=\hixj- #endif // _MSC_VER > 1000
Z1Qv>@u #ifndef __AFXWIN_H__
K>C@oE[W #error include 'stdafx.h' before including this file for PCH
0Y:)$h2? #endif
$ w+.-Tr #include "resource.h" // main symbols
=sAU5Ag68 class CHookApp : public CWinApp
Z*ag{N {
r`\@Fv, public:
fjy7 gC2 CHookApp();
[jksOC)@4 // Overrides
9s*QHCB0 // ClassWizard generated virtual function overrides
TY%=Y= //{{AFX_VIRTUAL(CHookApp)
B3pjli public:
$N Mu virtual BOOL InitInstance();
!K0 U.. virtual int ExitInstance();
i]OEhB
Y //}}AFX_VIRTUAL
$E.Fgy:G //{{AFX_MSG(CHookApp)
ANgt\8 // NOTE - the ClassWizard will add and remove member functions here.
P)#h4|xZ // DO NOT EDIT what you see in these blocks of generated code !
n/x((d%"E //}}AFX_MSG
/='Q-`?9 DECLARE_MESSAGE_MAP()
81C;D`!K };
M6bM`wHH> LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
{3.n!7+ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
CRD=7\0(D+ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Ql%B=vgKL BOOL InitHotkey();
UNK.39 BOOL UnInit();
Nukyvse #endif
V]GF53D tfu`_6 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
!
,{zDMA #include "stdafx.h"
S^;;\0#NK #include "hook.h"
~$C}?y^ a #include <windowsx.h>
!Z
0U_*& #ifdef _DEBUG
k DXQpe #define new DEBUG_NEW
;xiwyfqgE #undef THIS_FILE
;9~
WB X" static char THIS_FILE[] = __FILE__;
pwk Te #endif
~)n[Vf #define MAX_KEY 100
<*WGvCh%w #define CTRLBIT 0x04
3fA+{Y8S #define ALTBIT 0x02
X6T[+]Gc #define SHIFTBIT 0x01
W#E(?M[r #pragma data_seg("shareddata")
h"/'H)G7_& HHOOK hHook =NULL;
i]J.WFu UINT nHookCount =0;
_RbM'_y+E static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
>{9VXSc static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
J@"UFL'^ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
,RM8D)m\ static int KeyCount =0;
\I-e{'h static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
#p7gg61 #pragma data_seg()
1X7GM65# HINSTANCE hins;
tC(Ma I void VerifyWindow();
p2k`)=iX BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
"}#%h&, //{{AFX_MSG_MAP(CHookApp)
wy8Q=X:vP // NOTE - the ClassWizard will add and remove mapping macros here.
NbTaI{r // DO NOT EDIT what you see in these blocks of generated code!
V.*y_=i8t //}}AFX_MSG_MAP
w%plK6:6 END_MESSAGE_MAP()
Tl'wA^~H r>7+&s*yk CHookApp::CHookApp()
LnKgT1 {
Aj=GekX{ // TODO: add construction code here,
!h|,wq]k // Place all significant initialization in InitInstance
,Q3OQ[Nmh }
MBU|<tc ;']u}Nh CHookApp theApp;
@x!,iT LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
KO~KaN {
nlI3|5 BOOL bProcessed=FALSE;
{I0U 4] if(HC_ACTION==nCode)
~\i(bFd) {
l qwy5# if((lParam&0xc0000000)==0xc0000000){// Key up
[z ]P5 switch(wParam)
y.}{KQ"a* {
,msP(*qoI case VK_MENU:
1G"ohosmF MaskBits&=~ALTBIT;
*S"RU~1_ break;
dP(.l}O case VK_CONTROL:
%8h=_(X\7 MaskBits&=~CTRLBIT;
<7SE| break;
I.G[|[. Do case VK_SHIFT:
HA,8O[jon MaskBits&=~SHIFTBIT;
RgUQ: break;
t72u%M6 default: //judge the key and send message
eY'nS break;
4L ]4WVc }
7s3=Fa:9Q for(int index=0;index<MAX_KEY;index++){
iw=e"6V if(hCallWnd[index]==NULL)
sNcU>qjj6 continue;
p
JT)X8K" if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
/]'&cD 1 {
: r ~iFP* SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
J(@" 7RX bProcessed=TRUE;
8Iu6r}k?~` }
qg=`=]j }
mXyN{`q= }
U;4i&=.! else if((lParam&0xc000ffff)==1){ //Key down
"uT2 DY[ switch(wParam)
Y0krFhL'x0 {
9jY+0h*uP case VK_MENU:
+])<}S!M MaskBits|=ALTBIT;
A&p@iE*/ break;
[ 5!}+8]W case VK_CONTROL:
tpEy-"D& MaskBits|=CTRLBIT;
wpt$bqs|1 break;
nW"O+s3 case VK_SHIFT:
VevG 64o MaskBits|=SHIFTBIT;
K-)!d$$
break;
gd]S;<Jh default: //judge the key and send message
HcJ!( break;
o$l8"Uv }
=0]K(p, for(int index=0;index<MAX_KEY;index++)
y6tqemz {
yP"}(!~m if(hCallWnd[index]==NULL)
|;xEKnF continue;
JbL3/h] if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Dy,MQIM|! {
8s2y!pn7Q SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
U5wh( vi bProcessed=TRUE;
Zi+F IQ( }
u"(NN9s }
}4!}vkVx }
!j`<iPI7B if(!bProcessed){
UkpTK8>& for(int index=0;index<MAX_KEY;index++){
*]NfT}} if(hCallWnd[index]==NULL)
"_\"S continue;
6vAZLNG3 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
X/cb1# SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
BJb, }
&V$cwB }
h&CZN ! }
2ua!<^, return CallNextHookEx( hHook, nCode, wParam, lParam );
7yT/t1) }
fh3uo\`@ XPqGv=CN BOOL InitHotkey()
=v?P7;T {
VgIk '. if(hHook!=NULL){
H`fJ<So? nHookCount++;
}|2A6^FH. return TRUE;
PN?;\k)" }
COu5Tu^ else
xWXLk )A hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
@ Do.Wgt if(hHook!=NULL)
O50<h O]l nHookCount++;
_b&26!gl return (hHook!=NULL);
*cCx]C.~ }
j3;W-c`5 BOOL UnInit()
&U?4e'N)T {
Z8FgxR if(nHookCount>1){
<!FcQVH+L nHookCount--;
]s0wJD= return TRUE;
zps=~| }
/7\q#qIm: BOOL unhooked = UnhookWindowsHookEx(hHook);
]r0j if(unhooked==TRUE){
bAH<h
nHookCount=0;
YcX"Z~O6j= hHook=NULL;
TMY. z
}
95~bM;TVr return unhooked;
SO *oBA' }
=TNFAt tmq?h%O> BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
}:c~5whN {
4V4S5V BOOL bAdded=FALSE;
@@K/0:], for(int index=0;index<MAX_KEY;index++){
()Kaxcs?+ if(hCallWnd[index]==0){
kN1R8| pv hCallWnd[index]=hWnd;
"*D9.LyM HotKey[index]=cKey;
{+_p?8X HotKeyMask[index]=cMask;
8g!79q\c4 bAdded=TRUE;
Qx,#Hj KeyCount++;
G4:\6fu break;
3%(r,AD }
Be@g|'r }
R|(X_A return bAdded;
>Rt:8uurAG }
}=R0AKz!Cv :{)uD
; BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
5PZ7-WJ/ {
Q&{C%j~N BOOL bRemoved=FALSE;
t !6sU]{ for(int index=0;index<MAX_KEY;index++){
R|8L'H+1x if(hCallWnd[index]==hWnd){
EG qu-WBS if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
z-kv{y*Hu
hCallWnd[index]=NULL;
s<# BxN HotKey[index]=0;
h7fytO HotKeyMask[index]=0;
|3E|VGm~ bRemoved=TRUE;
DoFe:+_U3 KeyCount--;
Z]Udx break;
*,CJ 3<> }
lMu9Dp }
9y&;6V.' }
Xw'sh#i2 return bRemoved;
0nCiN;sA }
2e1%L,y{W [Z2[Iy void VerifyWindow()
\^9n&MonM {
}%?or_f/ for(int i=0;i<MAX_KEY;i++){
o96c`a u if(hCallWnd
!=NULL){ de2G"'F
if(!IsWindow(hCallWnd)){ fi>.X99(G
hCallWnd=NULL; 7Ko*`-p
HotKey=0; !y~nsy:&7x
HotKeyMask=0; *bYU=RS
KeyCount--; 2>^(&95M
} wMN;<