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:
h==GdS4
.(1j!B4^ 一、实现方法
9T,QWk '}`hY1v 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:
a61eH )a :_\!t45 #pragma data_seg("shareddata")
E9d i HHOOK hHook =NULL; //钩子句柄
K}=8:BaUL UINT nHookCount =0; //挂接的程序数目
UVCMB_T static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
\Tf{ui static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
UeQ9G static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
D'[P,v;Q static int KeyCount =0;
_Q}RElA static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
Px7g\[] #pragma data_seg()
inv{dg/2 /9+A97{ 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。
A Wh*<H lZA>L,
\d 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:
aho<w+l@ 3zA=q[C BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
y]pN=<*h5 cKey,UCHAR cMask)
]6%%X+$7 {
@
U8}sH^ BOOL bAdded=FALSE;
~:}XVt0%8 for(int index=0;index<MAX_KEY;index++){
qv*uM0G6i if(hCallWnd[index]==0){
h NOYFH hCallWnd[index]=hWnd;
"4k=(R? HotKey[index]=cKey;
r{!"%03H_ HotKeyMask[index]=cMask;
uU ?37V bAdded=TRUE;
9poEUjBI KeyCount++;
E"1;i break;
?tC}M;~ }
g.Caapy }
h,'mN\6t return bAdded;
V0'p1J tD }
.FbZVY c] //删除热键
h>^jq{yu BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
3@ F+ E\k {
c7l!G~yx' BOOL bRemoved=FALSE;
+z jzO]8 for(int index=0;index<MAX_KEY;index++){
>_0 i=.\ if(hCallWnd[index]==hWnd){
M`C~6Mf+ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
k`7.p,;}U hCallWnd[index]=NULL;
zUEfa!#? HotKey[index]=0;
R3{*v =ov HotKeyMask[index]=0;
[mB(GL bRemoved=TRUE;
rxgVT4 KeyCount--;
[rUh;_b\D break;
k|$"TFXx; }
}u3H4S<o }
;c
m wh< }
spU!t-n67 return bRemoved;
J'\eS./w|
}
%I|+_ z&x hKH$AEHEU} Ss<_K>wk DLL中的钩子函数如下:
Q 9gFTLQ Gx h~ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
4j@kMe;RjZ {
_> |R-vQ8 BOOL bProcessed=FALSE;
tgvpf/cQ if(HC_ACTION==nCode)
bco[L@6G$ {
y800(z if((lParam&0xc0000000)==0xc0000000){// 有键松开
0(hv #C4 switch(wParam)
orQV' {
17n+4J] case VK_MENU:
*t?~)o7 MaskBits&=~ALTBIT;
J+cAS/MYX break;
{Ukc D+.Y case VK_CONTROL:
4gv.E 0Fo MaskBits&=~CTRLBIT;
yYG3/Z3u5 break;
A1|7(Sow case VK_SHIFT:
94h_t@Q/1 MaskBits&=~SHIFTBIT;
0x]OF8=J break;
~D-JZx default: //judge the key and send message
RvPniT(<? break;
PV]k3&y }
w`.T/ for(int index=0;index<MAX_KEY;index++){
X #p o|,Q if(hCallWnd[index]==NULL)
h=K36a) continue;
e\^g|60f_ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
w]W`R. {
[V2omSZo SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
r(,= uLc bProcessed=TRUE;
da9*9yN }
clq~ ;hx }
9+'@ }
M}=s3[d(, else if((lParam&0xc000ffff)==1){ //有键按下
h+B'_`( switch(wParam)
?`N57'iPb {
l`v
+sV^1 case VK_MENU:
3XAp Y' MaskBits|=ALTBIT;
]F"(OWW break;
r sX$fU8 case VK_CONTROL:
TXd5v#_vo MaskBits|=CTRLBIT;
_uO!N(k. break;
B8cBQ v case VK_SHIFT:
-'O Q-5 MaskBits|=SHIFTBIT;
*l> [`U+ break;
.Ca"$2 default: //judge the key and send message
KdOh'OrT9. break;
D0Vyh"ua }
9S:{ for(int index=0;index<MAX_KEY;index++){
v+!y;N;Q
if(hCallWnd[index]==NULL)
2Y E;m& continue;
ba(arGZ+{ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
.0nn0)" {
OYszW]UMg SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
iA55yT+ bProcessed=TRUE;
}
*
?n?' }
d]O_E4X* }
lgkl? 0! }
#D|!
.I) if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
Z/89&Uy`h for(int index=0;index<MAX_KEY;index++){
lj
"Z if(hCallWnd[index]==NULL)
NCowt|#t continue;
a"0B?3*r46 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
4
[R8(U[g SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
QHHW(InG< //lParam的意义可看MSDN中WM_KEYDOWN部分
ZdE>C }
(R4PD }
z+3<$Z }
LJRg>8 return CallNextHookEx( hHook, nCode, wParam, lParam );
5y1or }
.-SDo"K.h g
,/a6M 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:
^%\)Xi I! h(` BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
'}U_D:o.b BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
T-L|Q,-{- M!eoe5 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=cN>ZMc 0K=Qf69Y LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
5kGxhD {
vKcl6bVT if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
1% $d D2 {
OOEV-= //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
=)(3Dp SaveBmp();
5SoZ$,a<e return FALSE;
NoFs-GGGh }
SQq6X63 \ …… //其它处理及默认处理
0lX)Cl }
mgi,b2 vVI6m{zYV 4`'8fe/" 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。
[8,PO ;EgzC^2e 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。
6OfdD.y
S304ncS|M 二、编程步骤
u9TzZ G 6Wx3~ 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";
( MB`hk-d W3 ^z Ij 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
`d75@0: c5X`_ 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;
m! rwG( F0@Qgk]\ 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;
@@'nit uWUR3n 5、 添加代码,编译运行程序。
3LKB; M,crz 三、程序代码
6!ZVd#OM% -G8c5b[ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
%0vTA_W #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
;(K #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
)8[ym/m #if _MSC_VER > 1000
q\a[S* #pragma once
o[o:A|n #endif // _MSC_VER > 1000
7N>oY$&) #ifndef __AFXWIN_H__
M{]e5+ #error include 'stdafx.h' before including this file for PCH
92!JKZe
#endif
Xc\*9XV: #include "resource.h" // main symbols
kt:)W])V class CHookApp : public CWinApp
UE^D2 u {
+AB6lv public:
DKh}Y
!Q=: CHookApp();
L'>s(CR // Overrides
p?;-!TUv // ClassWizard generated virtual function overrides
;_iPm?Y8 //{{AFX_VIRTUAL(CHookApp)
-<_7\09 public:
ue@8voZhS/ virtual BOOL InitInstance();
WElrk:b virtual int ExitInstance();
,!`SY) //}}AFX_VIRTUAL
L{=l#vu //{{AFX_MSG(CHookApp)
N;<//, // NOTE - the ClassWizard will add and remove member functions here.
lj)f4zu // DO NOT EDIT what you see in these blocks of generated code !
vK(I3db! //}}AFX_MSG
J2r1=5HS DECLARE_MESSAGE_MAP()
^"1TPd| };
cFLd)mt/ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
4GVNw!V BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
$'^&\U~? BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
YZibi BOOL InitHotkey();
X6xx2v%D BOOL UnInit();
DR6]-j!FK #endif
qh-[L B#]_8svO //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
tVunh3- #include "stdafx.h"
cqEHYJ;B #include "hook.h"
Xem 05%, #include <windowsx.h>
wy''tqg6 #ifdef _DEBUG
Sr&T[ex,. #define new DEBUG_NEW
N=#4L$@- #undef THIS_FILE
L!g DFZr static char THIS_FILE[] = __FILE__;
jPnO@H1 #endif
Uan,H1a #define MAX_KEY 100
M`~!u/D7 #define CTRLBIT 0x04
sMH#BCC #define ALTBIT 0x02
:lK4
db #define SHIFTBIT 0x01
p'&*r2_ram #pragma data_seg("shareddata")
:7\9xH HHOOK hHook =NULL;
h4Ia>^@ UINT nHookCount =0;
J^fm~P>. static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
PPa^o8jd
static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
+e'X; static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
7IW> >RBF static int KeyCount =0;
I_?He'=0oU static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
a\pi(9R #pragma data_seg()
pW{8R^vKm HINSTANCE hins;
/&h+t^l_Qj void VerifyWindow();
"V3}t4 BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
.B>B`q;B //{{AFX_MSG_MAP(CHookApp)
%,|ztH/ Q // NOTE - the ClassWizard will add and remove mapping macros here.
L~dC(J)@ZI // DO NOT EDIT what you see in these blocks of generated code!
YdI0E //}}AFX_MSG_MAP
IZ 8y}2 END_MESSAGE_MAP()
OC_M4{9/ t}Ss=0dJO CHookApp::CHookApp()
:mpiAs<%U" {
=OYQM<q // TODO: add construction code here,
A
W)a">| // Place all significant initialization in InitInstance
t[EfOQ }
(;}tf~~r #.<V^ CHookApp theApp;
6^;^rUlm LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Pd~MiyO;K {
2J<&rKCF BOOL bProcessed=FALSE;
hmZvIy( if(HC_ACTION==nCode)
f7J,&<<5w {
iITp**l if((lParam&0xc0000000)==0xc0000000){// Key up
C0fmmI0z~ switch(wParam)
YsP/p- {
!8*McOI case VK_MENU:
.$Bwb/a MaskBits&=~ALTBIT;
%9o+zg? RJ break;
o9Sn*p-. case VK_CONTROL:
1zjaR4Tf MaskBits&=~CTRLBIT;
ioV_oR9I break;
<C<`J{X0 case VK_SHIFT:
iq6a|XGi MaskBits&=~SHIFTBIT;
xMI+5b8 break;
~O:
U|& default: //judge the key and send message
|)o#|Qo
break;
EvE,Dm?h }
WJ+>e+ for(int index=0;index<MAX_KEY;index++){
Rg* J} if(hCallWnd[index]==NULL)
f-g1[!"F continue;
X
\f[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
([ dT!B#aH {
EfiU$8y SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
\ZD[!w7 bProcessed=TRUE;
`HW:^T }
\Hwg) Uc{ }
F98i*K`" }
1pP1d% else if((lParam&0xc000ffff)==1){ //Key down
`.=sTp2rbc switch(wParam)
rg5]&<Vq8 {
~ y;y(4< case VK_MENU:
jxw_*^w" MaskBits|=ALTBIT;
R8&|+ya break;
:eOR-}p' case VK_CONTROL:
nrpI5t.b MaskBits|=CTRLBIT;
8g*hvPc break;
*7" L]6 case VK_SHIFT:
4_LQ?U>$ MaskBits|=SHIFTBIT;
7>i2OBkAhB break;
W
f@t4(i default: //judge the key and send message
ALGgAX3t break;
d~*TIN8Ke~ }
{8@\Ij for(int index=0;index<MAX_KEY;index++)
tNnyue{p {
!e3YnlE if(hCallWnd[index]==NULL)
u+D[_yd^ continue;
kWL.ewTiex if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
4;KWG}~[o {
0JY WrPR SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
<7n]Ai@Y bProcessed=TRUE;
1H{jy^sP 7 }
R$m`Z+/@ }
DQJG,?e{ }
&mE?y% if(!bProcessed){
I^3:YVR& for(int index=0;index<MAX_KEY;index++){
&~-~5B|3" if(hCallWnd[index]==NULL)
1S$h<RIPAc continue;
Vq ^]s$' if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
!gP0ndRJ= SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Yck~xt&] }
N4UM82N }
9z ?7{2C }
K:5eek return CallNextHookEx( hHook, nCode, wParam, lParam );
*P2[qhP2 }
|n6Eg9 *'R#4@wmP BOOL InitHotkey()
A0xC,V~z {
~
3T,&?r if(hHook!=NULL){
&L4
q10-N nHookCount++;
2 x4= return TRUE;
lKV"Mh+6 }
onte&Ed\ else
)`HA:: hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
1u}nm;3 if(hHook!=NULL)
$Ui&D
I nHookCount++;
orIQ~pF# return (hHook!=NULL);
jo98
jA< }
m)&znLA BOOL UnInit()
SEF6B45}1 {
`UzVS>]l[+ if(nHookCount>1){
=P^wh nHookCount--;
+S~.c;EK return TRUE;
ii4B?E }
Mkv|TyC BOOL unhooked = UnhookWindowsHookEx(hHook);
X-JV'KE}^z if(unhooked==TRUE){
w1|Hy2D`0 nHookCount=0;
%_gho hHook=NULL;
|M5-5) }
68t}w^= return unhooked;
j+^L~, S }
y,m2(V H{fM%*w BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
6C-YyI#s# {
8_we:
9A BOOL bAdded=FALSE;
>HTbegi for(int index=0;index<MAX_KEY;index++){
IcF@F>> if(hCallWnd[index]==0){
85 ]SC$ hCallWnd[index]=hWnd;
;IZ?19Q HotKey[index]=cKey;
g]$
4~"|. HotKeyMask[index]=cMask;
<{ru|-9 bAdded=TRUE;
K5"sj|d& KeyCount++;
d"THt} break;
Q9>U1]\ }
(f1M'w/OD }
q<{NO/Mm return bAdded;
O`W%Tr }
k%Vv?{g g-)mav BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
cT'w= {
fCUT[d +H BOOL bRemoved=FALSE;
[Ot,q/hBJ for(int index=0;index<MAX_KEY;index++){
I6w~H?ul@* if(hCallWnd[index]==hWnd){
B)=~8wsI:Z if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
($!KzxF3 hCallWnd[index]=NULL;
rVryt<2:@r HotKey[index]=0;
ZX.TqvK/r HotKeyMask[index]=0;
XZph%j0o bRemoved=TRUE;
%c/^_. KeyCount--;
%:u[MBe , break;
$Ua56Y }
i|$z'HK;+ }
Ax<\jW< }
Z<z;L<tJ 9 return bRemoved;
VOgi7\ }
Rp.W,)i eaZQ2 void VerifyWindow()
_sMs}?^ {
r%=[},JQ for(int i=0;i<MAX_KEY;i++){
_p}xZD\?, if(hCallWnd
!=NULL){ zFhgE*5
if(!IsWindow(hCallWnd)){ #V_GOy1-
hCallWnd=NULL; mJ
HotKey=0; >bm|%Ou"
HotKeyMask=0; Ewo~9
4{
KeyCount--; Z=$T1|
} QT!5l`
} jNl/!l7B
} -|_ir-j
} DJ;g|b
pR$6,Vi
BOOL CHookApp::InitInstance() "S!3m9_#
{ <Gb
%uny
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 'Z8aPHD
hins=AfxGetInstanceHandle(); >1|g5
InitHotkey(); -q>^ALf|@>
return CWinApp::InitInstance(); fEnQE EU~P
} nkY@_N
!,&yyx.
int CHookApp::ExitInstance() EESN\_{~.
{ G*n2Ii
VerifyWindow(); j$@tK0P
UnInit(); `rFAZcEj%
return CWinApp::ExitInstance(); mP}#Ccji?
} Np,2j KF(
=,/D/v$m'2
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file xAdq+$><
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) d>i13dAI
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ Z`_.x
&Y
#if _MSC_VER > 1000 h'5Cp(G
#pragma once %FA@)?~
#endif // _MSC_VER > 1000 Fvl`2W94;
h%}(h2W
class CCaptureDlg : public CDialog <[Oo*:A!7
{ <