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:
$$ $[Vn_H<
hcW>R 一、实现方法
$mT)<N ;w /pRv
i>_(: 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
.8'c
c8 -I4@6vE, #pragma data_seg("shareddata")
,]t_9B QK HHOOK hHook =NULL; //钩子句柄
A#`$#CO UINT nHookCount =0; //挂接的程序数目
Lt~&K$t7~ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Eg&5tAyM static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
(0@b4}Z static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
_*z^PkH static int KeyCount =0;
OeGLMDw static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
E
6#/@C, #pragma data_seg()
md bi@ms@ y.(< 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。
jcC"vr'u| InL_JobE8r 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:
%4R1rUrgt| IPTFx
)]G BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
`#ff`j|a cKey,UCHAR cMask)
B3yTN6- {
jc3Q3Th/zn BOOL bAdded=FALSE;
k"=*' for(int index=0;index<MAX_KEY;index++){
2asRJ97qES if(hCallWnd[index]==0){
tW!*W? hCallWnd[index]=hWnd;
?}KD<R HotKey[index]=cKey;
J>M 9t%f@ HotKeyMask[index]=cMask;
fJNK@F bAdded=TRUE;
leF!Uog KeyCount++;
%INkuNa8\ break;
hKg +A }
IPn!iv) }
W2%@}IDm return bAdded;
+mft }
UFZOu%Y //删除热键
HP7~Zn)c BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
0`V=x+*, {
0i5S=L`j BOOL bRemoved=FALSE;
$U/lm;{% for(int index=0;index<MAX_KEY;index++){
*"OlO}o if(hCallWnd[index]==hWnd){
#Mk3cp^Yl if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
eU)QoVt hCallWnd[index]=NULL;
G]$EIf' HotKey[index]=0;
CL`+\
. HotKeyMask[index]=0;
T++q.oFc
bRemoved=TRUE;
@#^Y#
rxb KeyCount--;
iDcYyNE break;
|aU8WRq }
)n<p_vz }
uF[*@N }
Xe:rPxZf~ return bRemoved;
V$FZVG/@# }
NB44GP1-@ +BO kHXk1 T#6g5Jnsp DLL中的钩子函数如下:
Kwm_Y5`A CY.92I@S LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
S~H>MtX(< {
EUh_`R BOOL bProcessed=FALSE;
x|AND]^Q if(HC_ACTION==nCode)
<_kA+&T {
MSBrI3MqQ if((lParam&0xc0000000)==0xc0000000){// 有键松开
Y^DGnx("m switch(wParam)
3.P7GbN {
Xf"<
>M case VK_MENU:
1he5Zevm} MaskBits&=~ALTBIT;
v>nBdpjXh break;
rtbV*@Z case VK_CONTROL:
2yFT` 5+H4 MaskBits&=~CTRLBIT;
_E8Cvaob break;
W2v'2qAs case VK_SHIFT:
Gj%q:[r MaskBits&=~SHIFTBIT;
4i&Rd1#0dI break;
8mLW^R:` default: //judge the key and send message
$0OOH4 break;
&PApO{#Q }
S[hyN7sI for(int index=0;index<MAX_KEY;index++){
+e.w]\} if(hCallWnd[index]==NULL)
T~L V\}h continue;
q$b4S4Z7 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
_NwHT`O[ {
br TP}A SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
9@IL5 47V bProcessed=TRUE;
NX8hFwR }
2"shB(:z> }
QBi]gT@&g }
}CZw'fhVWO else if((lParam&0xc000ffff)==1){ //有键按下
JC9$"0d7 switch(wParam)
g]N'6La {
tcRJ1:d case VK_MENU:
cX4]ViXSr MaskBits|=ALTBIT;
K1R?Qt,qDF break;
{_L l'S case VK_CONTROL:
G9am}qr MaskBits|=CTRLBIT;
?*xH
HI/ break;
ypGt6t(; case VK_SHIFT:
oP4+:r)LKD MaskBits|=SHIFTBIT;
<s\ZqL$f break;
h 6IXD N default: //judge the key and send message
>!lpI5'Z& break;
E`@Z9k1 ` }
dKD:mU",M for(int index=0;index<MAX_KEY;index++){
%,<Ki]F if(hCallWnd[index]==NULL)
."O%pL]!/b continue;
h6?Z if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
z$~F9Es9 {
I
S'Uuuz7g SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Olh{<~Fv bProcessed=TRUE;
'|yCDBu }
@- xvdntx }
X6(s][Wn }
\G)F* if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
9iM%kY#)W for(int index=0;index<MAX_KEY;index++){
S3WUccv if(hCallWnd[index]==NULL)
2P^qZDG 8I continue;
Wi!"Vcn if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
TXyiCS3 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Px*<-t|R- //lParam的意义可看MSDN中WM_KEYDOWN部分
djw\%00 }
|Ox='.oIb }
xYW&Mfka }
@^.W|Zh[& return CallNextHookEx( hHook, nCode, wParam, lParam );
VlL%dN;
0 }
53a^9 j!%^6Io4 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
^Mc9MZ) |</) 6r BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
(C).Vj~ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
Ar,n=obG FY^Nn 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
|S|'o*u s0D4K LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
jf)l; \u {
`=,emP&(H& if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
M;OMsRCVO {
{i8zM6eC //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
LGW_7&0<< SaveBmp();
&(32s! qH return FALSE;
-MTYtw( }
Kr|.I2?" …… //其它处理及默认处理
^[Ka+E^Q }
)78T+7Kq R)\^*tkz7 BbCO K 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
woPj>M NIbK3`1 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
{]dtA&8( Ov?J"B'F 二、编程步骤
IOuqC.RJ}o S1mMz
i 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
kL0K[O -]D/8,|s 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
Pgy[\t 2K 6W=V8 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
7C3YVm6g fbbbTZy 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
Dat',5 3z2
OW@zL$ 5、 添加代码,编译运行程序。
6(4d3}F 6Xm'^T 三、程序代码
T:m"
eD; CPRVSN0b{4 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
h"0)spF"d #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
u5glKE #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
h !R=t #if _MSC_VER > 1000
ArNQ}F/ #pragma once
p@4GI[ 4 #endif // _MSC_VER > 1000
0NC70+4L #ifndef __AFXWIN_H__
7dACbqba #error include 'stdafx.h' before including this file for PCH
pb)8?1O|s #endif
(?JdiY/ #include "resource.h" // main symbols
bDtb6hL class CHookApp : public CWinApp
fC*cqc~{@ {
-,p=;t#( public:
ZcyGLg0I CHookApp();
7>F{.\Z // Overrides
+>vKI8g*RH // ClassWizard generated virtual function overrides
[x>Ju&))$ //{{AFX_VIRTUAL(CHookApp)
9CeR^/i public:
6:Z8d%Z virtual BOOL InitInstance();
tLfhW1" virtual int ExitInstance();
Cgh84
2% //}}AFX_VIRTUAL
NE8W--Cg| //{{AFX_MSG(CHookApp)
tB,(12@W // NOTE - the ClassWizard will add and remove member functions here.
GjHR.p?- // DO NOT EDIT what you see in these blocks of generated code !
q=BljSX //}}AFX_MSG
!@8i(!xb DECLARE_MESSAGE_MAP()
VK1B}5 / };
}F _c0zM LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
KbvMp1'9P BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
ZCPUNtOl BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
fTvm2+.nX BOOL InitHotkey();
X
V;j6g BOOL UnInit();
`a|&aj0 #endif
}P
fAf A&~fw^HM //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
TxP+?1t #include "stdafx.h"
<L#d<lx #include "hook.h"
}>u `8'2v #include <windowsx.h>
H%>4z3n
#ifdef _DEBUG
u%)gnj_ #define new DEBUG_NEW
3+>n!8x ;A #undef THIS_FILE
d>8"-$ static char THIS_FILE[] = __FILE__;
o1$u;}^ | #endif
4<F
z![> #define MAX_KEY 100
%(lO>4>| #define CTRLBIT 0x04
CYW@Km{e #define ALTBIT 0x02
$%cc[[/U #define SHIFTBIT 0x01
)XK\[tL #pragma data_seg("shareddata")
$P0q! HHOOK hHook =NULL;
'!Hs"{~{ UINT nHookCount =0;
6,3o_"J! static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
Nq6'7'x static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
GN(<$,~g static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
!ou#g5Q@z static int KeyCount =0;
jBw)8~tYm static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
K -rR)-rI #pragma data_seg()
ls]N&!/hq HINSTANCE hins;
V<0iYi;4= void VerifyWindow();
CPP~,E_ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
?";SUku //{{AFX_MSG_MAP(CHookApp)
,=m.WmXE // NOTE - the ClassWizard will add and remove mapping macros here.
Jd>~gA}l // DO NOT EDIT what you see in these blocks of generated code!
s51$x M //}}AFX_MSG_MAP
J @"# END_MESSAGE_MAP()
+hmFFQQ} .w.:o2L CHookApp::CHookApp()
LJ(WU)CPc {
=
(F // TODO: add construction code here,
-o6rY9\_! // Place all significant initialization in InitInstance
-y+>^45 }
: OY~Q3
@ 'cXdc CHookApp theApp;
UUJQc~= LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
ilL0=[2 {
"S%t\ BOOL bProcessed=FALSE;
EX`P(=zD if(HC_ACTION==nCode)
EbQLMLD% {
`S@TiD* if((lParam&0xc0000000)==0xc0000000){// Key up
)O~[4xV~ switch(wParam)
S 13cQ?4 {
GrL{q;IO case VK_MENU:
^QRg9s,T< MaskBits&=~ALTBIT;
|:=o\eu& break;
/8h=6" case VK_CONTROL:
H0Pxw
P>q MaskBits&=~CTRLBIT;
Bvn3:+(47 break;
neDXzMxF case VK_SHIFT:
G:=hg6' MaskBits&=~SHIFTBIT;
ZYwcB]xEz break;
WD[eoi default: //judge the key and send message
my.EvN break;
u#E'k
KGO }
pSw/QO9 for(int index=0;index<MAX_KEY;index++){
v~P,OP("c if(hCallWnd[index]==NULL)
o|(5Sr&H continue;
NXY jb(4: if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
I#M3cI!X? {
;!4gDvm SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
M<fhQJ bProcessed=TRUE;
`a& kD|Yh }
yLX $SR }
ATNOb }
1PkCWRpR else if((lParam&0xc000ffff)==1){ //Key down
@^W`Yg)C switch(wParam)
18>cfDh;N {
%t9C case VK_MENU:
DmiBM6t3N MaskBits|=ALTBIT;
N6Ud(8* break;
W_\zx<m case VK_CONTROL:
%fqR MaskBits|=CTRLBIT;
wSTulo: 9 break;
hArY$T&MB case VK_SHIFT:
TC\+>LXiZ MaskBits|=SHIFTBIT;
!+T1kMP+l break;
?['!0PF default: //judge the key and send message
}vd*eexA break;
SiratkP9n7 }
SAx9cjj+ for(int index=0;index<MAX_KEY;index++)
]k0
jmE {
x *eU~e_jP if(hCallWnd[index]==NULL)
,fVD`RR(W? continue;
p
T(M>LP83 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Ux[<g%F" {
V2YK T,5 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
M?$[WS bProcessed=TRUE;
>Jz9wo` }
y>^^. }
IHl q27O }
^OR0Vp>L if(!bProcessed){
5'~_d@M for(int index=0;index<MAX_KEY;index++){
_kj]vbG^; if(hCallWnd[index]==NULL)
"s*-dZO continue;
J!6FlcsZm if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
RLB3 -=9t SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
*T|B'80 }
-4a9 BE". }
#WpkL]g2+% }
{meX2Z4 return CallNextHookEx( hHook, nCode, wParam, lParam );
nM
)C^$3<t }
O !L`0
=%c VM"cpC_8 BOOL InitHotkey()
*eVq(R9?T {
'X`Z1L/ if(hHook!=NULL){
yPm2??5MW> nHookCount++;
/Rp]"S
vt return TRUE;
[I $+wWW_ }
RpHlq else
;?-AFd\i hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
hvd}l8 if(hHook!=NULL)
Y::0v@&( nHookCount++;
lfGyK4: return (hHook!=NULL);
C$3*[ }
T(4d5 fY BOOL UnInit()
]T4/dk&|o^ {
kIrrbD if(nHookCount>1){
yVd^A2
nHookCount--;
-EjXVn! vQ return TRUE;
$`=p] }
f-=\qSo BOOL unhooked = UnhookWindowsHookEx(hHook);
:$ 5A3i if(unhooked==TRUE){
gg;r;3u nHookCount=0;
E h%61/ hHook=NULL;
5jdZC(q5a }
^[L(kHOGzk return unhooked;
J~Xv R }
] $ew 5% [uq>b|`RG BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
pMc6p0 {
fCl}eXg6w BOOL bAdded=FALSE;
]Z JoC!u for(int index=0;index<MAX_KEY;index++){
XC4Z ,,ah" if(hCallWnd[index]==0){
,g`%+s7 u hCallWnd[index]=hWnd;
c}x1-d8 HotKey[index]=cKey;
X'9.fKp HotKeyMask[index]=cMask;
X|M!Nt0' bAdded=TRUE;
E-MPFL KeyCount++;
+jN}d=N- break;
!XA3G`}p6s }
7p&jSOY }
XX;4A return bAdded;
30Yis_l2h }
bdUPo+ "}]`64? BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
# kI> {
R#(0C(FI^ BOOL bRemoved=FALSE;
F /b`[ for(int index=0;index<MAX_KEY;index++){
X>%nzY]m if(hCallWnd[index]==hWnd){
3P>gDQP if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
_`$LdqgE hCallWnd[index]=NULL;
)vr@:PE HotKey[index]=0;
j)1y v. HotKeyMask[index]=0;
uGKjZi bRemoved=TRUE;
e5h*GKF KeyCount--;
.u`[|:K break;
q!K:N? }
D-3[#~MV }
|Td+,>, }
4DXbeQs: return bRemoved;
CU$khz" }
aM^iDJ$> )oEVafNsT void VerifyWindow()
gU9{~-9} {
-!\3;/ for(int i=0;i<MAX_KEY;i++){
\?:L>-&h8 if(hCallWnd
!=NULL){ T?9D?u?]
if(!IsWindow(hCallWnd)){ *P()&}JK
hCallWnd=NULL; NOz3_k
HotKey=0; @0`A!5h?u
HotKeyMask=0; TFVQfj$r
KeyCount--; ,N/@=As9$
} D{|q P
nE4
} E3L?6Qfx>
} I8F+Z
} ]!UYl
~iw&^p|=K
BOOL CHookApp::InitInstance() J=V
{ gmTBT#{6yH
AFX_MANAGE_STATE(AfxGetStaticModuleState()); wZrFu(_
hins=AfxGetInstanceHandle(); xQ?>72grP
InitHotkey(); g14*6O:
return CWinApp::InitInstance(); #kg`rrFr
} _iwG'a[`
4"@<bKx
int CHookApp::ExitInstance() jA? #!lx_
{ c=\tf~}^Ms
VerifyWindow(); (5a73%>@
UnInit(); P{L=u74b{x
return CWinApp::ExitInstance(); 7GA8sK
} Wj{lb_Rj
UuG%5 ZC
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file F[qXIL)
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) t2&kGf"
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ :WhJDx`j
#if _MSC_VER > 1000 sW^M
]
#pragma once &K[*vyD
#endif // _MSC_VER > 1000 5s7BUT
ROO*/OOd
class CCaptureDlg : public CDialog Z\$HgG
{ uL'f8Pqg
// Construction N_t,n^i9>*
public: (1/Sf&2i
BOOL bTray; OhF55,[
BOOL bRegistered; DF%d/a{]
BOOL RegisterHotkey(); G1:}{a5i_
UCHAR cKey; EIi<g2pM(
UCHAR cMask; %lKw+D
void DeleteIcon(); %zavSm"
void AddIcon(); S :HOlJze
UINT nCount; :]"5UY?oF
void SaveBmp(); OY*y<