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:
MVUJD{X#
A?OQE9' 一、实现方法
FW DNpr }"%N4(Kd 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:
* kh tJ]= 6j|{`Zd)G #pragma data_seg("shareddata")
)%fH(ns( HHOOK hHook =NULL; //钩子句柄
(S Yln>o UINT nHookCount =0; //挂接的程序数目
gbD KE{ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
2y1Sne=<Kb static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
SUK?z!f<i static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
lPAQ3t!, static int KeyCount =0;
SSzIih@u static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
,|/f`Pl #pragma data_seg()
X2'0PXv>! &mM0AA'\?H 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。
ti,d&c_7 Q\0'lQJdy 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:
E' uZA eS){1 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
}c:M^Ff cKey,UCHAR cMask)
G=bCNn< {
[()koU#w. BOOL bAdded=FALSE;
5SQ8}Or3 for(int index=0;index<MAX_KEY;index++){
[mueZQyI?0 if(hCallWnd[index]==0){
YuwI&)l hCallWnd[index]=hWnd;
|;{6&S HotKey[index]=cKey;
7_[L o4_ HotKeyMask[index]=cMask;
>=w)x,0yX bAdded=TRUE;
2MK-5Kg KeyCount++;
dlnX_+((KC break;
^xk'Z }
K)iF>y|{*q }
WTiD[u return bAdded;
iH'p>s5L }
bcz:q/f}@ //删除热键
M
D#jj3y BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
"$vRMpW: {
/BL4<T f BOOL bRemoved=FALSE;
)Q JUUn# for(int index=0;index<MAX_KEY;index++){
HjwE+: w if(hCallWnd[index]==hWnd){
r:
:b if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
PQE=D0 hCallWnd[index]=NULL;
JlJ a
# HotKey[index]=0;
cidP|ie^ HotKeyMask[index]=0;
?\n>
AC bRemoved=TRUE;
zKK9r~ M KeyCount--;
bW:!5"_{H break;
7-V/RChBm }
o#N+Y?O }
NCD04U5y }
dD@(z:5M\ return bRemoved;
>.D4co> }
?r!o~|9| U%/+B]6jP <{cQ2 DLL中的钩子函数如下:
CU~PT. A/?7w
LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
(QiAisE {
VS|2|n1<6 BOOL bProcessed=FALSE;
$NO&YLS@ if(HC_ACTION==nCode)
;9'OOz|+1 {
@KUWxFak if((lParam&0xc0000000)==0xc0000000){// 有键松开
'we>q@ switch(wParam)
#,v{Ihn {
m)D|l1AtF case VK_MENU:
@[v~y"tE} MaskBits&=~ALTBIT;
H%lVl8oQ break;
W!(LF7_! case VK_CONTROL:
q75s#[<ap MaskBits&=~CTRLBIT;
(uidNq break;
Wn}'bqp case VK_SHIFT:
6d~'$<5on MaskBits&=~SHIFTBIT;
EB|}fz break;
S5EK~#-L[ default: //judge the key and send message
?Ss!e$jf break;
]J]h#ZHx }
{(?4!rh for(int index=0;index<MAX_KEY;index++){
pmYHUj
# if(hCallWnd[index]==NULL)
!Xw5<J3L- continue;
(C)p9-, if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
|sZHUf_ {
f|oh.z_R SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
f`66h M[ bProcessed=TRUE;
9(<@O%YU }
Yu`~U,m }
r:TH]hs12+ }
wwcBsJ1{ else if((lParam&0xc000ffff)==1){ //有键按下
^LzF@{ G switch(wParam)
_h1mF<\ X^ {
7 Fsay+a case VK_MENU:
@9|hMo MaskBits|=ALTBIT;
PeEj&4k break;
U,1-A=Og{o case VK_CONTROL:
={Qi0Pvt MaskBits|=CTRLBIT;
{BU;$ break;
Y`wSv NU case VK_SHIFT:
sW8dPw
O MaskBits|=SHIFTBIT;
Q=yg8CQ break;
?!/kZM_ts default: //judge the key and send message
jb!i$/%w break;
IMONgFBS }
lU8Hd|@- for(int index=0;index<MAX_KEY;index++){
ENY+^7 if(hCallWnd[index]==NULL)
#:%/(j continue;
FJ?IUy 6 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
aC)!T {
x]ot 2 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
^pk7"l4Xm bProcessed=TRUE;
,
++ `=o }
0_t!T'jr7 }
sCHJ&>m5- }
y"wShAR if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
FaJ &GOM, for(int index=0;index<MAX_KEY;index++){
k"w"hg&e if(hCallWnd[index]==NULL)
JqiP>4Uwm^ continue;
SasJic2M if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
UFuX@Lu0 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
*c+ (- //lParam的意义可看MSDN中WM_KEYDOWN部分
(Ep\Z 6* }
'2^Q1{ :\ }
'uEl~> l7 }
@F*%9LPv return CallNextHookEx( hHook, nCode, wParam, lParam );
h'F=YF$o }
&:)Wh[ ~e@z;]CiY 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:
[cp+i^f L;I]OC^J BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
sLQ^F BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
8X|-rM{ H_Q+&9^/ 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:
0"bcdG<} d>C$+v> LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
'b{]:Y {
`W*U4?M if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
D}X\Ca"h {
N?"] //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
@sC`!Rmy'- SaveBmp();
kPLxEwl return FALSE;
W6/yn }
:6\qpex …… //其它处理及默认处理
]?[fsdAQW }
e^D]EA]% FJP-y5 s-T\r"d=j 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。
0:Ol7 )P|),S,;Z 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。
"LTad`]<Ro A~t
j/yq9 二、编程步骤
BR yl4 }U"&8%PZr 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";
W:L
AP
R WI-1)1t 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
6V01F8&w u:_,GQ )\ 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;
;;N9>M?b U\*J9 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;
AkQ~k0i}b !d0kV,F: 5、 添加代码,编译运行程序。
7O-x<P; H~1jY4E 三、程序代码
w&T9;_/ SNI)9k(T{ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
;hN!s`vq #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
nc|p ) #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
5"O.,H} #if _MSC_VER > 1000
^3L0w}# #pragma once
cHt#us #endif // _MSC_VER > 1000
|_@>*Vmg #ifndef __AFXWIN_H__
IB]l1< #error include 'stdafx.h' before including this file for PCH
j+
0I-p #endif
VS8Rx.? #include "resource.h" // main symbols
]-/VHh class CHookApp : public CWinApp
?2Py_gkf {
:! !at:> public:
Qn)a/w- CHookApp();
bB3powy9 // Overrides
UrEs4R1# // ClassWizard generated virtual function overrides
+ @s"zp;F //{{AFX_VIRTUAL(CHookApp)
O[JL+g4
public:
6G""I]uT virtual BOOL InitInstance();
7! INkH] virtual int ExitInstance();
5taT5?n2 //}}AFX_VIRTUAL
{[?(9u7R //{{AFX_MSG(CHookApp)
1NA.nw. // NOTE - the ClassWizard will add and remove member functions here.
J]pir4&j // DO NOT EDIT what you see in these blocks of generated code !
N U` //}}AFX_MSG
6gu!bu`~ DECLARE_MESSAGE_MAP()
CdjI` };
lchPpm9 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
sN01rtB(UT BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
6zuTQ^pz BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
ou{2@" BOOL InitHotkey();
%^1V4 BOOL UnInit();
<1${1A <Wa #endif
[j/9neaye N~zdWnSZ@G //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
#fn)k1 #include "stdafx.h"
6fEqqUeV #include "hook.h"
pYmk1!]/ #include <windowsx.h>
%S^8c #ifdef _DEBUG
.;`AAH'k #define new DEBUG_NEW
K} X&AJ5A #undef THIS_FILE
=R$u[~Xl2X static char THIS_FILE[] = __FILE__;
@>Km_Ax #endif
t)$:0 #define MAX_KEY 100
"n5N[1bk #define CTRLBIT 0x04
q ,]L$ #define ALTBIT 0x02
ra
g Xn #define SHIFTBIT 0x01
O`t&ldU #pragma data_seg("shareddata")
l L@XM2" HHOOK hHook =NULL;
y(yHt=r UINT nHookCount =0;
`Cynj+PCe static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
$1L>)S static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
9w"4K. static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
1JG'%8}#8 static int KeyCount =0;
L2i_X@/ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
Pw`8Wj #pragma data_seg()
nV/G8SeI HINSTANCE hins;
y'nK>)WG4 void VerifyWindow();
B7E:{9l~s{ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
u[=r,^YQ //{{AFX_MSG_MAP(CHookApp)
0gP}zM73 // NOTE - the ClassWizard will add and remove mapping macros here.
ShP^A"Do // DO NOT EDIT what you see in these blocks of generated code!
u.m[u)HQ //}}AFX_MSG_MAP
XnMvKPerv' END_MESSAGE_MAP()
~/iKh11 9`X\6s CHookApp::CHookApp()
1FL~ndJs {
LxSpctiNx // TODO: add construction code here,
!")tU+: // Place all significant initialization in InitInstance
h_3E)jc }
Nkth>7* W/bQd)Jvk CHookApp theApp;
Ee%%d LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
`MN4uC {
,77d(bR< BOOL bProcessed=FALSE;
_FU_Ubkr if(HC_ACTION==nCode)
$AjHbU.I{ {
Ed df2;-. if((lParam&0xc0000000)==0xc0000000){// Key up
.glA
gt switch(wParam)
)e=D(qd {
;rGwc$?| case VK_MENU:
cj|80$cSA MaskBits&=~ALTBIT;
U-(01- break;
Kaqc74Mv case VK_CONTROL:
Vl=l?A8 MaskBits&=~CTRLBIT;
a;qryUyG break;
=M[bnq*\ case VK_SHIFT:
PQSP& MaskBits&=~SHIFTBIT;
jB Z&Ad@e break;
Q}K"24`= default: //judge the key and send message
b;W3j break;
&4x}ppX }
0#s"e}@v for(int index=0;index<MAX_KEY;index++){
)|R)Q6UJ if(hCallWnd[index]==NULL)
t[;LD_ continue;
5o'FS{6U if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
U!?_W=? {
;oKZ!ND SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
6"5A%{J bProcessed=TRUE;
6"O+w=5B }
qHplJ " }
r|fL&dtr }
Ls$D$/:q? else if((lParam&0xc000ffff)==1){ //Key down
_~J
{wM switch(wParam)
"R1NG?;q {
#64-~NVL_ case VK_MENU:
(pCrmyB MaskBits|=ALTBIT;
F Q7T'G![ break;
< #}5IQ5`Z case VK_CONTROL:
~IfJwBn-i MaskBits|=CTRLBIT;
tGh~!|P break;
Ms5ap<q# case VK_SHIFT:
n,V[eW#m'L MaskBits|=SHIFTBIT;
p{Yv3dNl break;
F^t DL: default: //judge the key and send message
wc NOLUl break;
"fCu=@i }
p;59? for(int index=0;index<MAX_KEY;index++)
gx8ouOh {
k"T}2 7 if(hCallWnd[index]==NULL)
$m%fwB continue;
mAj?>;R2$2 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
,j2Udn}
{
V6&!9b SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Yz/md1T$ bProcessed=TRUE;
jrlVvzZ }
~ Ei $nV }
RK'\C\gMDu }
GmeQ`;9, if(!bProcessed){
hz;G$cuEE for(int index=0;index<MAX_KEY;index++){
h-#6av: if(hCallWnd[index]==NULL)
Ic"ybj` continue;
Pw7]r<Q if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
u<6<iD3y SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
J!v3i*j\ }
iwZPpl"; }
F3v!AvA| }
x=hiQ>BIO0 return CallNextHookEx( hHook, nCode, wParam, lParam );
-aPg#ub }
?Wr+Q b9KP( _ BOOL InitHotkey()
HZzD VCU {
G_3O]BMKd) if(hHook!=NULL){
j^j1 nHookCount++;
\:# L) return TRUE;
G~^r)fm_ }
fo*2:?K& else
H1pO!>M hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
=)H.cuc if(hHook!=NULL)
w(*vj nHookCount++;
+qtJaYf/0 return (hHook!=NULL);
(lBCO?`fx }
(>UZ<2GPL BOOL UnInit()
2\A$6N;_ {
UUYSFa% if(nHookCount>1){
g|DF[ nHookCount--;
N=T<_`$5 return TRUE;
U3ADsdn }
Cx(>RXVoJ, BOOL unhooked = UnhookWindowsHookEx(hHook);
Fh?gNSWq6 if(unhooked==TRUE){
??-[eB. nHookCount=0;
0U(@=7V hHook=NULL;
67JA=,EE }
1b `1{% return unhooked;
~ drS} V }
Gv!2f 6"LcJ%o BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
U2tV4_ e {
iW]j9} t BOOL bAdded=FALSE;
v}}F,c(f for(int index=0;index<MAX_KEY;index++){
7Utn\l if(hCallWnd[index]==0){
b$d;Qx hCallWnd[index]=hWnd;
'%s.^kn HotKey[index]=cKey;
acajHs HotKeyMask[index]=cMask;
?Ny9'g>? bAdded=TRUE;
9N#_(uwt KeyCount++;
0rQMLx break;
E<{R.r }
.;y.]Z/; }
Z,
zWuE3 return bAdded;
aD<A.Lhy }
QUwd [ j78i#}e BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
%~O,zs.2p {
er("wtM BOOL bRemoved=FALSE;
''A_[J `> for(int index=0;index<MAX_KEY;index++){
2@n{yYwy if(hCallWnd[index]==hWnd){
[`#CXq' if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
@wGPqg hCallWnd[index]=NULL;
SB;&GHq"n HotKey[index]=0;
.9/hHCp HotKeyMask[index]=0;
;V:i!u u bRemoved=TRUE;
&&5aM KeyCount--;
0#7>o^2 break;
n*R])=F@c }
YquI $PV _ }
'Cb6Y#6 }
}kw#7m54 return bRemoved;
lZd(emH@ }
7cuE7" :(E@Gf void VerifyWindow()
5N#aXG^9 {
A]_7}<<N for(int i=0;i<MAX_KEY;i++){
NlA,'`, if(hCallWnd
!=NULL){ oM
X
if(!IsWindow(hCallWnd)){ lF<]8m%F
hCallWnd=NULL; n2"a{Ofhlf
HotKey=0; gldAP:
HotKeyMask=0; Q4#.X=.d
KeyCount--; on!,c>nNa
} HDz5&