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:
zqCr'$
fG"4\A 一、实现方法
yc7"tptfF INNTp[ 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:
WQ1K8B4 VJbn/5+P #pragma data_seg("shareddata")
O5v~wLx9e HHOOK hHook =NULL; //钩子句柄
1$n!Lj=5 UINT nHookCount =0; //挂接的程序数目
os[i static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
c~)H" n static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
3gQ2wP*K static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
#,S0uA static int KeyCount =0;
=`EVg>+^ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
&BOG&ot #pragma data_seg()
}$oZZKS \R.Fmeko 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。
,<O|#`?"@G CyKupJ.Fq 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:
z{(c-7* M?v`C>j BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
fO{'$?K cKey,UCHAR cMask)
s*tzU.E( {
fq(3uE]nC BOOL bAdded=FALSE;
g0k{b for(int index=0;index<MAX_KEY;index++){
rd ]dDG if(hCallWnd[index]==0){
2#_i_j hCallWnd[index]=hWnd;
7Um3myXU HotKey[index]=cKey;
HV[*=Qi HotKeyMask[index]=cMask;
[&5%$ T bAdded=TRUE;
{(5M)|> KeyCount++;
RD6`b_]o break;
83pXj=k< }
|IZFWZd }
um=qT)/D return bAdded;
|>dqZ_)v }
H|8i|vbi //删除热键
GmdS~Fhp BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
ia*Bcx_RW+ {
tD+K4
^ BOOL bRemoved=FALSE;
=SK{|fBB for(int index=0;index<MAX_KEY;index++){
*kq>Z 06'i if(hCallWnd[index]==hWnd){
&\5%C\0Z< if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
A)HV#T`N hCallWnd[index]=NULL;
;@/vKA3l. HotKey[index]=0;
iu+rg(*% HotKeyMask[index]=0;
D8=a +!l- bRemoved=TRUE;
PS/00F/Ak KeyCount--;
FQBAt0 break;
~+&Z4CYb }
QN8.FiiD }
9V?:!%J }
,K8(D<{ return bRemoved;
=P`l+k3 }
yr
q){W +<7a$/L?4 lQt* LWd[ DLL中的钩子函数如下:
(R^Ca7F A08{]E#v> LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
m ol|E={si {
9D H}6fO BOOL bProcessed=FALSE;
R zn%!d^$> if(HC_ACTION==nCode)
!^IAn {
x`Ik747^v if((lParam&0xc0000000)==0xc0000000){// 有键松开
o]WG8Mo- switch(wParam)
X@^"@ {
N6uKFQL:{ case VK_MENU:
4L/8Hj#g MaskBits&=~ALTBIT;
(E<QA break;
/u pDbP.O case VK_CONTROL:
3sz?49tX MaskBits&=~CTRLBIT;
&DX break;
i4\m/&of3y case VK_SHIFT:
[8rl{~9E MaskBits&=~SHIFTBIT;
X.)D"+xnH break;
tRmH6
default: //judge the key and send message
^<v]x;
3 break;
S1E=EVG }
V"W)u#4, for(int index=0;index<MAX_KEY;index++){
*S\/l-D if(hCallWnd[index]==NULL)
:'K%&e?7s continue;
$#HUxwx4 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Sj9NhtF]f {
Z)dE#A_X SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
hgI;^ia
bProcessed=TRUE;
|C3~Q{A }
{on+
;, }
Jsw%.< }
Bw*6X`'Q else if((lParam&0xc000ffff)==1){ //有键按下
/]hE?cmj switch(wParam)
5 $:
q {
5}he)2*uD case VK_MENU:
;eiqzdP MaskBits|=ALTBIT;
)NCSO b break;
Qhsk09K_=4 case VK_CONTROL:
6^vHFJ$ MaskBits|=CTRLBIT;
"6xTh0D
break;
4kdQ h] case VK_SHIFT:
SAtK 'Jx[ MaskBits|=SHIFTBIT;
@Yzc?+x break;
="AJ&BqHd default: //judge the key and send message
pb=yQ}. break;
MP%pEUomev }
07qL@![! for(int index=0;index<MAX_KEY;index++){
W6L}T,epX if(hCallWnd[index]==NULL)
[y1
x`WOk9 continue;
N83g=[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
JN<IMH {
"M4gl SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Ilv
_. bProcessed=TRUE;
>TQnCG= }
&Ez]pKjB }
riY[p, }
ma7@vD if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
;sfk@ec for(int index=0;index<MAX_KEY;index++){
["
nDw<U if(hCallWnd[index]==NULL)
dT4e[4l continue;
mZb[Fi if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
z\r|5Z SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
*u?N{LkqS //lParam的意义可看MSDN中WM_KEYDOWN部分
(H-Y-Lk+ }
;OY*`(Id }
/%5X:*:H }
IiRII)
return CallNextHookEx( hHook, nCode, wParam, lParam );
XbL\l }
/8tF7Mmr A3c&VT6Q 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:
;,Q6AS! /;\{zA$uC= BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
YMTB4|{ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
{ 0vHgi eE-c40Bae 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
0Rze9od]$ 1pHt3Vc(G LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
>5+]~[S {
s^Wh!:>r/ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
~<&47'D {
ye-R //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
_Vf0MU;3f+ SaveBmp();
bRb+3au_x
return FALSE;
~f:jI1(} }
|m /XGr …… //其它处理及默认处理
';OZP2 }
a>/cVu'kz GUqhm$6a
wk (}q 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。
a54qv^IS PDH00(#;+ 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。
6m!%X GZT i%a jL 二、编程步骤
] f~mR_E qD?-&>dBWi 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";
=Zc
Vywz;+ QwL'5ws{q 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
sU}.2k FsyM{LT 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;
/vG)n9Rc ^J_rb;m43 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;
GVt}\e~" S|HnmkV66 5、 添加代码,编译运行程序。
g4fe(.?c, Z_Z; g]|! 三、程序代码
T6=q[LpsKN aO]FQ#l2b ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
=f*Wj\ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
WPzq?yK #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
8>y!=+9_ #if _MSC_VER > 1000
?E88y #pragma once
_6,Tb] #endif // _MSC_VER > 1000
9X6l`bo' #ifndef __AFXWIN_H__
Jf|6 FQo& #error include 'stdafx.h' before including this file for PCH
dDoKmuY>5 #endif
#Z.2g]. #include "resource.h" // main symbols
lqe71](sK8 class CHookApp : public CWinApp
ddiBjp2.! {
07:N)y, public:
aur4Ky> : CHookApp();
V=LJ_T"z0 // Overrides
si|DxDx // ClassWizard generated virtual function overrides
wqyrs|P //{{AFX_VIRTUAL(CHookApp)
d:V6.7>, public:
/o)o7$6Q virtual BOOL InitInstance();
fX[6
{ virtual int ExitInstance();
v1Wz#oP //}}AFX_VIRTUAL
[O52Bn //{{AFX_MSG(CHookApp)
/K2=GLl; // NOTE - the ClassWizard will add and remove member functions here.
!<P|:Oo*Dl // DO NOT EDIT what you see in these blocks of generated code !
E6FT*}Q //}}AFX_MSG
mtQlm5l DECLARE_MESSAGE_MAP()
%oY=.Ok ] };
Xzp!X({ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
vuCl(/P` BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
*He%%pk BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
h72#AN BOOL InitHotkey();
78[5@U BOOL UnInit();
0nbQKoF #endif
*>,CG:`D V<+=t{ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
j~a"z4 0 #include "stdafx.h"
6YCFSvA#/ #include "hook.h"
k-uwK-B}v+ #include <windowsx.h>
~&?{hd. #ifdef _DEBUG
(,5,} #define new DEBUG_NEW
QIg.r\>o #undef THIS_FILE
;}BDEBl static char THIS_FILE[] = __FILE__;
NLLLt #endif
O5:2B\B #define MAX_KEY 100
=Hs[peO* #define CTRLBIT 0x04
s/"?P/R #define ALTBIT 0x02
X>`5YdT~+ #define SHIFTBIT 0x01
">pt,QV #pragma data_seg("shareddata")
'"/Yk=EmlU HHOOK hHook =NULL;
XW*,Lo5>H\ UINT nHookCount =0;
@\|W#,~ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
=vaC?d3 static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
z:_o3W.E static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
U=a'(fX static int KeyCount =0;
#r ;;d( static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
10 D6fkjf #pragma data_seg()
GvCB3z HINSTANCE hins;
8 FqhSzw void VerifyWindow();
RTgR>qI&) BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
|<q9Ee //{{AFX_MSG_MAP(CHookApp)
gPu0j4&- // NOTE - the ClassWizard will add and remove mapping macros here.
JXBTd=r_oM // DO NOT EDIT what you see in these blocks of generated code!
#cRw0bn: //}}AFX_MSG_MAP
7oK7f=*Q END_MESSAGE_MAP()
:+m8~n$/ )O~V3a CHookApp::CHookApp()
\z4I'"MC.9 {
@@O=a // TODO: add construction code here,
{B_pjs // Place all significant initialization in InitInstance
fuQb h }
z+Cw*v\Y d
Xiv8B1 CHookApp theApp;
*<[Nvk^ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
yl=_ /'* {
}95;qyQ$ BOOL bProcessed=FALSE;
E_[)z%&n2 if(HC_ACTION==nCode)
*61+Fzr {
q*^F"D:?k if((lParam&0xc0000000)==0xc0000000){// Key up
4%3R}-'mh switch(wParam)
S-8wL%r {
2KUm(B.I case VK_MENU:
@DYxDap{ MaskBits&=~ALTBIT;
EPZ^I) break;
P9\!JH! case VK_CONTROL:
.Kn)sD1 MaskBits&=~CTRLBIT;
D]s8w break;
x'.OLXx> case VK_SHIFT:
z`^DQ8+\j MaskBits&=~SHIFTBIT;
?)ROQ1-#@ break;
g@<E0
q&`$ default: //judge the key and send message
bHi0N@W!vG break;
oBm^RHTZ }
z/,qQVv=}4 for(int index=0;index<MAX_KEY;index++){
!2R<T/9~ if(hCallWnd[index]==NULL)
n8!qz:z/ continue;
aa'u5<<W if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
0x-58i0 {
"0nT:!BZ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
bvuoo/ bProcessed=TRUE;
@Y~R*^n"} }
|9;6Cp }
,EAf/2C }
!&3iZQGWv else if((lParam&0xc000ffff)==1){ //Key down
~is$Onf99# switch(wParam)
q:y_#r"_y {
/lC&'h T case VK_MENU:
sUfYEVjr MaskBits|=ALTBIT;
>|"mhNF break;
vu&%e\gM case VK_CONTROL:
Zj*kHjn" MaskBits|=CTRLBIT;
L+c7.l.yT break;
&!y7PWHJ case VK_SHIFT:
:< )"G& MaskBits|=SHIFTBIT;
q]-CTx$ break;
j#C1+Us default: //judge the key and send message
p;GT[Ds^ break;
|b@H]c;" }
$ylQ \Y' for(int index=0;index<MAX_KEY;index++)
\G3P[E[ {
j A 9! if(hCallWnd[index]==NULL)
)]=1W
continue;
98%M`WY if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
<h$Nh0 {
^k'?e"[gTs SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
g=*`6@_= bProcessed=TRUE;
_::q
S! }
Lqt.S| }
h "7:&=e }
PJ=N.xf} if(!bProcessed){
N(%%bHi#V for(int index=0;index<MAX_KEY;index++){
ii.L]#3y if(hCallWnd[index]==NULL)
bN,>,hj continue;
aAlES< r if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
LIo3a38n?y SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
hdw-ge m{? }
+B
4&$z }
$#cZJ@;] }
'THcO*< return CallNextHookEx( hHook, nCode, wParam, lParam );
92@/8,[ }
JYY:~2
d$3;o&VUNI BOOL InitHotkey()
wIrjWU2 {
.HM1c if(hHook!=NULL){
Y:~A-_ nHookCount++;
l1_Tr2A}7/ return TRUE;
UN~dzA~V }
!J5k?J&{= else
!n=?H1@ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
NhI&wl if(hHook!=NULL)
D# $Fj nHookCount++;
BZ] 6W/0 return (hHook!=NULL);
!besMZ }
;B 35E!QJ BOOL UnInit()
YWV"I|Z {
U{IY
F{;@ if(nHookCount>1){
7j>NUx=j3 nHookCount--;
^4+ew>BLSv return TRUE;
;g3z?Uz) }
d},IQ,Az:Z BOOL unhooked = UnhookWindowsHookEx(hHook);
lZY0A#
if(unhooked==TRUE){
AoaRlk-# nHookCount=0;
E&\dr;{7 hHook=NULL;
>@NH Al }
BFU6?\r return unhooked;
g>lJZD@ }
m15MA.R> fn%Gu s~ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
u|!On {
0ssKZ9Lc BOOL bAdded=FALSE;
*V\z]Dy-[ for(int index=0;index<MAX_KEY;index++){
/Hox]r]'e if(hCallWnd[index]==0){
iqzl (9o.D hCallWnd[index]=hWnd;
sr0.4VU1 HotKey[index]=cKey;
.6,+q2tyk, HotKeyMask[index]=cMask;
(xp<@- bAdded=TRUE;
Ywj=6 +; KeyCount++;
CDDx %#eG> break;
7x/S4Gs'4 }
E<[_L!2 }
-BY'E$]4 return bAdded;
bv.DW,l%' }
Q?f%]uGFQ }(g`l)OX BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
1g_(xwUp+ {
6sRe. ct<