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:
,:{+-v(
5,BvT>zFY 一、实现方法
vs{VRc N>iNz[a
q 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:
RS|*3
$1 .7+"KP: #pragma data_seg("shareddata")
,E8g~ZUY9 HHOOK hHook =NULL; //钩子句柄
`NyO|9/4 UINT nHookCount =0; //挂接的程序数目
t^=S\1"R\ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
/A-VT static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
YlXqj\a static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
^}UFtL i static int KeyCount =0;
&srD7v9M8 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
";upu #pragma data_seg()
od^o9(.W^ wauM|/KG 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
h(i_'P? R ^"*ut DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
TpYdIt9#> \1eWI BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
zhh6;>P cKey,UCHAR cMask)
a_zf*; {
Z ?ATWCa BOOL bAdded=FALSE;
@vO~'Xxq! for(int index=0;index<MAX_KEY;index++){
!>WW(n07Ma if(hCallWnd[index]==0){
?[.g~DK, hCallWnd[index]=hWnd;
WHr:M/qD HotKey[index]=cKey;
.PCbGPbk HotKeyMask[index]=cMask;
AgWG4C= bAdded=TRUE;
!N/?b^y KeyCount++;
uFG ;AY| break;
UoJMOw[ }
4rypT-%^ ; }
AQPzId*z return bAdded;
+WvW#wpH }
]_hXg*? //删除热键
w69G6G( BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
kZQ$Iv+^( {
Bm;@}Ly=G BOOL bRemoved=FALSE;
YVO~0bX: for(int index=0;index<MAX_KEY;index++){
$oIGlKc:L if(hCallWnd[index]==hWnd){
lAAP V if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
_mDvRFq hCallWnd[index]=NULL;
7mYBxE/ HotKey[index]=0;
'D?sRbJ= HotKeyMask[index]=0;
Ifj%" RI bRemoved=TRUE;
c#pVN](? KeyCount--;
CM+wkU ?, break;
*4 Kc "M }
9z(h8H }
kN*\yH| }
9R|B 5. return bRemoved;
<PQ[N[SU }
uzL IllVX* I`}x 9t <~Tfi*^+ DLL中的钩子函数如下:
:w4I+*] !n5s/"'H LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
]I0(_e|z} {
Oxf,2r BOOL bProcessed=FALSE;
Xu\2 2/Co if(HC_ACTION==nCode)
'p(I!]"uo {
%suXp,j if((lParam&0xc0000000)==0xc0000000){// 有键松开
3WF6bJN switch(wParam)
<txzKpM {
kx3]A"]>' case VK_MENU:
LL=nMoS MaskBits&=~ALTBIT;
L QP4#7 break;
E- rXYNfy case VK_CONTROL:
oNBYJ]t MaskBits&=~CTRLBIT;
!yX4#J( break;
N
@sVA%L. case VK_SHIFT:
AT,?dxP J MaskBits&=~SHIFTBIT;
y'pX/5R0 break;
@g'SH:} default: //judge the key and send message
4U1"F 7' break;
xo*[
g`N }
g3uI1]QXLg for(int index=0;index<MAX_KEY;index++){
j!<RY>u if(hCallWnd[index]==NULL)
k`Ifd:V.y continue;
+']S if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
>|So`C3:e {
(T0%H<#+ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
2*1s(Jro bProcessed=TRUE;
t Sf` }
s"\o6r
, }
0UT2sM$ }
&4O0}ax*Zm else if((lParam&0xc000ffff)==1){ //有键按下
h47l;`kD-# switch(wParam)
)7Ed}6% {
Wc)f:]7 case VK_MENU:
MM%c MaskBits|=ALTBIT;
slKL(-D{ break;
fX2PteA0qX case VK_CONTROL:
{?9s~{Dl MaskBits|=CTRLBIT;
YEx76 break;
pB;p\9A*q case VK_SHIFT:
-*EK-j MaskBits|=SHIFTBIT;
0oi
=}lV break;
nn_j"Nu default: //judge the key and send message
m,U`hPJ break;
}9xEA[@; }
}$ Am;%?p for(int index=0;index<MAX_KEY;index++){
qe:,%a-9 if(hCallWnd[index]==NULL)
+)fl9>Mb continue;
@M-+-6+ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
pU*dE
{
QMfa~TH#p SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
y3K9rf bProcessed=TRUE;
1v4( }
B&`hvR }
\@4_l?M }
<"@~
if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
p_jDnb# for(int index=0;index<MAX_KEY;index++){
*Ki ],>_~ if(hCallWnd[index]==NULL)
5B?>.4R continue;
mlY0G w_e if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Y$ ;C@I SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
2Ek6YNx //lParam的意义可看MSDN中WM_KEYDOWN部分
e1X*}OI }
V>j6Juh }
g`!:7|&,_ }
,iU ]zN// return CallNextHookEx( hHook, nCode, wParam, lParam );
++:v O }
Dm6}$v'0 .foM>UOY 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:
p
IXBJk qDO4&NO BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
+'?p $@d BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
FG-w7a2mn s,Cm}4L6 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
A}sb2P {b>tX)Tep LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
2i4FIS|z0 {
,ORZtj if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
rO/mK$ {
X|H%jdta //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
T"'"T]^
X SaveBmp();
&eT)c<yhyK return FALSE;
oq=D9 }
YZf<S: …… //其它处理及默认处理
bv>;%TF }
86~HkHliv FK{YRt l0g#&V-- 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。
-@G|i$! fM_aDSRa!H 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
gy _86y@ %lV&QQa 二、编程步骤
jcN84AaRFI kqSCKY1 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
mUzNrkG(G *~M=2Fj;i 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
3~BL!e, z?h\7
R 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
b/ 'fC%o, ^v3ytS 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
<dDGV>n4;
+GgWd=X.Y 5、 添加代码,编译运行程序。
N-
? U2V LDW":k| 三、程序代码
{.z2n>1J{T
C+,;hj ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
)m"NO/sJ2 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
D*`|MzlQ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
t</rvAH E #if _MSC_VER > 1000
:HRJ49a #pragma once
N6$pOQ #endif // _MSC_VER > 1000
9C$b^wHd #ifndef __AFXWIN_H__
2;5EH0 #error include 'stdafx.h' before including this file for PCH
Us M|OH5k #endif
+XJj:%yt #include "resource.h" // main symbols
06pLa3oi class CHookApp : public CWinApp
C!B2.:ja {
1a| q&L`o public:
z*l3O~mZ CHookApp();
RERum // Overrides
85m[^WGyh // ClassWizard generated virtual function overrides
6~0S%Hz //{{AFX_VIRTUAL(CHookApp)
AASw^A3p public:
,JN2q]QPP virtual BOOL InitInstance();
~o= Sxaf virtual int ExitInstance();
bec n$R //}}AFX_VIRTUAL
WHqp7NPl //{{AFX_MSG(CHookApp)
utQE$0F // NOTE - the ClassWizard will add and remove member functions here.
CwTx7
^qa // DO NOT EDIT what you see in these blocks of generated code !
v6HBO#F'V{ //}}AFX_MSG
K!5QFO4 DECLARE_MESSAGE_MAP()
*|Q'?ty(x };
V
z8o LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
#!OCEiT_ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
W @`Nn*S BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
)(9>r/bq BOOL InitHotkey();
O>wGc8Of\ BOOL UnInit();
S WVeUL#5 #endif
[95(%&k.Q L|qQZ= //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
(8qMF{ #include "stdafx.h"
Nlx7"_R"Q #include "hook.h"
UQaLhKv: #include <windowsx.h>
'LpJ:Th #ifdef _DEBUG
sk\U[#ohH #define new DEBUG_NEW
Q`4= #undef THIS_FILE
ZvpcjP static char THIS_FILE[] = __FILE__;
?!U=S=8 #endif
<MB]W`5 #define MAX_KEY 100
xKWqDt #define CTRLBIT 0x04
=zDU!< U #define ALTBIT 0x02
P_B# #define SHIFTBIT 0x01
Ah;2\0|t #pragma data_seg("shareddata")
\6-x~%xK HHOOK hHook =NULL;
-ZlBg~E UINT nHookCount =0;
]{{A/ j\ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
jA$g0> static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
01g=Cg static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
o%i^t4J$e static int KeyCount =0;
`utv@9 _z static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
P,k~! F^L #pragma data_seg()
vp?87h HINSTANCE hins;
0^az<!!O# void VerifyWindow();
NeAkJG=< BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
"CLoM\M) //{{AFX_MSG_MAP(CHookApp)
QG*=N {%5 // NOTE - the ClassWizard will add and remove mapping macros here.
y >r7(qg // DO NOT EDIT what you see in these blocks of generated code!
j5,1`7\7B //}}AFX_MSG_MAP
5ppOG_ END_MESSAGE_MAP()
XAwo~E 0?KXQD CHookApp::CHookApp()
`E+)e?z {
91qk0z`N // TODO: add construction code here,
px %xoY // Place all significant initialization in InitInstance
Aayh'xQ }
_*7h1[,{f LSQWveZz CHookApp theApp;
u?5d%]* LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
\ZX5dFu0 {
Z"#eN(v.N BOOL bProcessed=FALSE;
[Oen{c9A if(HC_ACTION==nCode)
k"D6Vyy` {
5LdVcXf if((lParam&0xc0000000)==0xc0000000){// Key up
BZejqDr* switch(wParam)
lffp\v{w {
Gdmh#pv case VK_MENU:
&[:MTK?x! MaskBits&=~ALTBIT;
W2/FGJD break;
d~F`q7F'?] case VK_CONTROL:
=M'M/vKD MaskBits&=~CTRLBIT;
^]l^q'?>: break;
b&[9m\AX` case VK_SHIFT:
E9z^# @s MaskBits&=~SHIFTBIT;
kP~'C'5Ys break;
9qN4f8R default: //judge the key and send message
)]WWx-Uf' break;
KiYO,nD;\ }
w}No ^.I*4 for(int index=0;index<MAX_KEY;index++){
2 w\$}' if(hCallWnd[index]==NULL)
@Gp=9\L continue;
.w2QiJ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
S$J}>a#Ry {
(uW/t1 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
U<,@u,_Ja bProcessed=TRUE;
{6{y"8 }
wI.i\S }
[M>Md-pj }
88}+.-3t$ else if((lParam&0xc000ffff)==1){ //Key down
w1HE^
/ switch(wParam)
j,%@%upM {
r@N 0%JZZ case VK_MENU:
K$OxeJP?F MaskBits|=ALTBIT;
S<}2y 9F
break;
[-o`^; case VK_CONTROL:
Gt#Jr!N~ MaskBits|=CTRLBIT;
s2f95<B break;
/2}o:vLj case VK_SHIFT:
iEx.BQ+ MaskBits|=SHIFTBIT;
r@C2zF7 break;
ZeewGa^r default: //judge the key and send message
~RcI+jR) break;
HScj
}
i0F.c\ for(int index=0;index<MAX_KEY;index++)
VBc[(8o {
kN3 T/96 if(hCallWnd[index]==NULL)
I9O9V[ continue;
\zj _6Os if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
d:/8P985 {
[]HMUL]" SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
YnnpgR. bProcessed=TRUE;
fR_
jYP1 }
rM<lPMr1* }
!sda6?& }
89@\AjI if(!bProcessed){
W{E22J} for(int index=0;index<MAX_KEY;index++){
n8(B%KF if(hCallWnd[index]==NULL)
36>pa continue;
gfE<XrG if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
9hAS#|vK SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
rkhQoYZ[ }
w:Ui_-4*> }
*8}Y0V\s }
34VyR
a return CallNextHookEx( hHook, nCode, wParam, lParam );
B5J!&suX }
H5t 9Mg| X!5N2x BOOL InitHotkey()
[c4.E" {
T1zft#1~ if(hHook!=NULL){
$>E\3npV nHookCount++;
.0]4@' return TRUE;
_'&N0 1 }
l,uYp"F,ps else
SsA;T5:6 hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
fr'M)ox1 if(hHook!=NULL)
L'{;V\d nHookCount++;
"sLdkd}dj return (hHook!=NULL);
f@l 6]z{.L }
h}xUZ: BOOL UnInit()
OJE<2:K {
M9Gs^ if(nHookCount>1){
XfA3Ez,} nHookCount--;
#QJ
mAA return TRUE;
ln.kEhQ3B }
\V@SCA' BOOL unhooked = UnhookWindowsHookEx(hHook);
-oq!zi4: if(unhooked==TRUE){
3WyK!@{ nHookCount=0;
8>x.zO_.c> hHook=NULL;
A9PXu\%y }
mY-Z$8r return unhooked;
*ggTTHy }
2rHw5Wn]~ j`Lf/S!} BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
-Nmf}`_ {
ANSv ZqKh BOOL bAdded=FALSE;
dsDoPo0! for(int index=0;index<MAX_KEY;index++){
j)\g0u6 if(hCallWnd[index]==0){
vl$! To9R" hCallWnd[index]=hWnd;
a:@9GmtV& HotKey[index]=cKey;
)hk=wu6 HotKeyMask[index]=cMask;
^vm[`M bAdded=TRUE;
Y0BvN`E KeyCount++;
jIE>t5 fy break;
/Nq!^= }
$oE 4q6b }
q?z6|]M|u return bAdded;
?>MD /l(l }
$}oQ=+c5 3DK^S2\zBm BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
:w_F<2d0
0 {
r0G#BPgdR BOOL bRemoved=FALSE;
vVyO}Q` for(int index=0;index<MAX_KEY;index++){
3sGrX"0D if(hCallWnd[index]==hWnd){
;t%L(J if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
0vG}c5;F hCallWnd[index]=NULL;
GQqw(2Ub} HotKey[index]=0;
V.WfP*~NJ HotKeyMask[index]=0;
2BH>TmS bRemoved=TRUE;
$Br^c< y KeyCount--;
mXc/sh")X break;
5K'EuI) }
37p0*%a": }
1ISA^< M }
:EgdV return bRemoved;
};9dd3X }
3+A 0O%0* u-UUF void VerifyWindow()
! qrF=a {
};o R x) for(int i=0;i<MAX_KEY;i++){
*(?YgV if(hCallWnd
!=NULL){ ]kb%l"&
if(!IsWindow(hCallWnd)){ 1)_f9GR
hCallWnd=NULL; I-/PzL<W P
HotKey=0; ^%_B'X9
HotKeyMask=0; TeqFy( Dr
KeyCount--; gY0*u+LF
} s^C*uP;R
} $L</{bXW
} {w!}:8p
} eBU\&