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:
?0) @jc=
P5P<" 一、实现方法
$Elkhe]O % ]5)"gL%H` 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
sv`"\3N[
p[ Hr39o #pragma data_seg("shareddata")
u>}zm_ HHOOK hHook =NULL; //钩子句柄
n.ct]+L UINT nHookCount =0; //挂接的程序数目
snq;:n! static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Ro~fvL~Ps static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
}Aw47;5q; static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
BV1u,<T" static int KeyCount =0;
b!,ja? static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
O]bKNA.5 #pragma data_seg()
ofK='G. #fj[kq)&S 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
s>r ^r%uK gi1j/j7 DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
eo ?Oir) OEI3eizgH BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
\OA
L Or cKey,UCHAR cMask)
m_$JWv\|\ {
zQ<88E&&Xs BOOL bAdded=FALSE;
"qE {a>d for(int index=0;index<MAX_KEY;index++){
J?,?fqb if(hCallWnd[index]==0){
F^miq^K=
hCallWnd[index]=hWnd;
I{EIHD< HotKey[index]=cKey;
-$9~xX HotKeyMask[index]=cMask;
}7Jp :. qk bAdded=TRUE;
}_]As}E KeyCount++;
sjb-Me? break;
2m_H*1HJ }
9cz )f\ }
v4C3uNW return bAdded;
ng
9NE8F }
oSmjs //删除热键
PU"S;4m BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
-F1P28<? {
NZfd_? 3 BOOL bRemoved=FALSE;
Lrlk* for(int index=0;index<MAX_KEY;index++){
2^J/6R$ if(hCallWnd[index]==hWnd){
zu<>"5}] if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
]1tN|ODY*W hCallWnd[index]=NULL;
}H; ]k-) HotKey[index]=0;
<ZV7|'^ HotKeyMask[index]=0;
Hva{A
# bRemoved=TRUE;
H6{Rd+\Z KeyCount--;
Txu>/1N, break;
kR_E6Fl }
QU,?}w'?d }
c[Yq5Bu{y }
PYaOH_X. return bRemoved;
3}yraX6r! }
=@%MV( [RW,{A 9c%(]Rn: DLL中的钩子函数如下:
kHZKj!!R sv@}x[L LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
dbd"pR 8v {
/lru"R D BOOL bProcessed=FALSE;
aK-N}T if(HC_ACTION==nCode)
f}A^]6MO: {
*x5o=)Y if((lParam&0xc0000000)==0xc0000000){// 有键松开
C>M6&= switch(wParam)
Mg&HRE {
7@3M]5:3g case VK_MENU:
aQC7 V !v MaskBits&=~ALTBIT;
3EO#EYAHiM break;
.ZM]%[4 case VK_CONTROL:
L{zamVQG MaskBits&=~CTRLBIT;
qgh]@JJh break;
<x ^IwS case VK_SHIFT:
MuN[U17FB MaskBits&=~SHIFTBIT;
Ogn,1nm% break;
^j1Gmv) default: //judge the key and send message
bl6':m+ break;
*'s&/vEy }
CdE2w?1 for(int index=0;index<MAX_KEY;index++){
;H`=):U if(hCallWnd[index]==NULL)
>I{4 continue;
|P^ikx6f5 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
X}kVBT1w+x {
}kpfJLjY SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
^Jc$BMaVg bProcessed=TRUE;
hn*}5!^ }
\nn56o@eN }
m/SJ4op$ }
jqV)V> M. else if((lParam&0xc000ffff)==1){ //有键按下
HE8'N=0 switch(wParam)
Z:W')Nd( {
!]n{l_5r case VK_MENU:
,K"r:)\ MaskBits|=ALTBIT;
r! cNc break;
yL^M~lws case VK_CONTROL:
Z_ iQU1
MaskBits|=CTRLBIT;
vY8WqG] break;
Te{aB"B case VK_SHIFT:
:Q0?ub] MaskBits|=SHIFTBIT;
y$+!%y* break;
'M]CZ} default: //judge the key and send message
$_%2D3-;D break;
D~[N_ }
HY@kw>I for(int index=0;index<MAX_KEY;index++){
b6rzHnl{ if(hCallWnd[index]==NULL)
4DG 9`5. continue;
oRtY?6^$ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
w>1l@%Uo {
LrmtPnL SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
R(n0!h4 bProcessed=TRUE;
}kgjLaQ^N }
&Nj:XX;X }
59"Nn\}3gE }
J7&.>y1% if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
f6(9wz$Trt for(int index=0;index<MAX_KEY;index++){
?trt4Tbe/ if(hCallWnd[index]==NULL)
.$}Z:,aB
continue;
*R9mgv[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
ZipK;!9by SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
[|m>vY! //lParam的意义可看MSDN中WM_KEYDOWN部分
!<['iM }
OmoplJ+ }
hCOy\[2$ }
pX h^M{. return CallNextHookEx( hHook, nCode, wParam, lParam );
<W^XSk }
HC<BGIgL 9
up*g 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:
uV*f[l [4+a 1/^ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
$O8EiC!f6 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
iX9[Q0g=oQ TnZc.
为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
G+\~rl f@x( ,p LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
>x _:=%Wr+ {
NiJ?no if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
a\HtxR8L {
@Tm0T7C //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
jW+VUF-t SaveBmp();
5jCEy*%P@ return FALSE;
*F4G qX3 }
#VMBn} …… //其它处理及默认处理
A?{aUQB~| }
KI?1(L uBL~AC3>O /v5g;x_T 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
Q/9vDv 5IF~]5s 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
h}VYA\+<B J|64b 二、编程步骤
Ul~}@^m]4} )*QTxN 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
=ym~=
S ;hJ/t/7 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
0_xcrM 3E2.v5* 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
Zo638*32 %cjGeS6} 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
}JTgj gt~2Br4 5、 添加代码,编译运行程序。
)^'B:ic =rtA{g$)+ 三、程序代码
Q9'p3"yoE 7J_f/st ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
R8W44I*R: #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
((IBaEq #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
Oj|p`Dzh #if _MSC_VER > 1000
,8 NEnB #pragma once
oX]1>#5UMg #endif // _MSC_VER > 1000
B+H9c~3$ #ifndef __AFXWIN_H__
Ak-7}i #error include 'stdafx.h' before including this file for PCH
!5 :[X vI# #endif
xwp?2,< #include "resource.h" // main symbols
umn~hb5O class CHookApp : public CWinApp
%+W
>+xRb {
4 AmF^H public:
V4i%|vV CHookApp();
T-8nUo}i // Overrides
B91PlM. // ClassWizard generated virtual function overrides
}
K-[/; //{{AFX_VIRTUAL(CHookApp)
m-FDCiN> public:
4W-+k virtual BOOL InitInstance();
.`#R%4Xl virtual int ExitInstance();
w=>mG- //}}AFX_VIRTUAL
6zZR:ej //{{AFX_MSG(CHookApp)
cZT.vA# // NOTE - the ClassWizard will add and remove member functions here.
Ca"+t
lO // DO NOT EDIT what you see in these blocks of generated code !
_Vf|F //}}AFX_MSG
ffd3QQ DECLARE_MESSAGE_MAP()
=9@yJ9c- };
;<R_j%* LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
~*]`XL.- BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
A+E@OO w*~ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
y%l#lz=6 BOOL InitHotkey();
QNwAuH T BOOL UnInit();
]lYEJ` #endif
8J U~Q <5vB{)Tq //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
2,nCGSfc #include "stdafx.h"
X_@@v|UF #include "hook.h"
l<%~w
U #include <windowsx.h>
uL AXN #ifdef _DEBUG
'Rw]
C[ #define new DEBUG_NEW
Z-!T(:E] #undef THIS_FILE
o_m.MMEU static char THIS_FILE[] = __FILE__;
,X6j$YLWp #endif
o^6 j(~ #define MAX_KEY 100
IomJo #define CTRLBIT 0x04
DQnWLC"u #define ALTBIT 0x02
2` qXDfD` #define SHIFTBIT 0x01
3mz>Y*^?0 #pragma data_seg("shareddata")
<ft9B05* HHOOK hHook =NULL;
dF]8>jBOL UINT nHookCount =0;
H2cc).8" static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
X6 cb#s0| static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
M3`A&*\; static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
K a|\gl;V static int KeyCount =0;
1=.kH[R static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
EBLoRW=8ld #pragma data_seg()
/MtacR HINSTANCE hins;
S`KCVQ>V void VerifyWindow();
nP31jm+A BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
D<6kAGE //{{AFX_MSG_MAP(CHookApp)
ir#^5e@ // NOTE - the ClassWizard will add and remove mapping macros here.
\M@8# k| // DO NOT EDIT what you see in these blocks of generated code!
!{;RtUPz* //}}AFX_MSG_MAP
Ts6X:D4, END_MESSAGE_MAP()
Hm*#HT%# "FS.&&1( CHookApp::CHookApp()
JqZ5DjI: {
fh<G&E8
p // TODO: add construction code here,
_AHVMsz@ // Place all significant initialization in InitInstance
UkV] F] }
TKX# / KW<CU' CHookApp theApp;
+Z*%,m=N( LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
$)V4Eu; {
JM%#L *; BOOL bProcessed=FALSE;
p<e~x/@m* if(HC_ACTION==nCode)
gId+hxFa:r {
P0=F9`3wb if((lParam&0xc0000000)==0xc0000000){// Key up
(6{
VMQ switch(wParam)
wBET.l'd {
LAeX e!y case VK_MENU:
3>6o=7/PU MaskBits&=~ALTBIT;
a{W-+t break;
3F1Z$d( case VK_CONTROL:
,}0pK\Y>$ MaskBits&=~CTRLBIT;
yNL71 >w4 break;
]u ';zJ. case VK_SHIFT:
%ZK}y{u\ MaskBits&=~SHIFTBIT;
!w Bmf&= break;
-tQ|&fl default: //judge the key and send message
*&D=]fG break;
1F|+4 }
Tx(R3B+u7 for(int index=0;index<MAX_KEY;index++){
jo~Pr if(hCallWnd[index]==NULL)
MR}\fw$(. continue;
&bRH(yF if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
cx|j
_5%i {
XvdhPOMy SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
bBX~ZWw bProcessed=TRUE;
A?/?9Gr }
$m>e!P>%u }
gi)/iz ` }
@4i DN else if((lParam&0xc000ffff)==1){ //Key down
_$0Ix6y, switch(wParam)
5h1j.t! {
}W<L;yD case VK_MENU:
N5\<w> MaskBits|=ALTBIT;
/Q!F/HY3ZS break;
vF,l?cU~ case VK_CONTROL:
VsC]z,
oV MaskBits|=CTRLBIT;
s@$AYZm_ break;
P(`IY+ case VK_SHIFT:
u2t<auE9^ MaskBits|=SHIFTBIT;
pqe**`z@y break;
luMNi^FQ default: //judge the key and send message
AS7!FD6b break;
n>HN py }
-cKR15 for(int index=0;index<MAX_KEY;index++)
",}VB8K {
0e7!_/9 if(hCallWnd[index]==NULL)
Q%7EC>V continue;
g_=Q=y@, if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
'.=Z2O3p {
G<-.{Gx) SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
^tah4QmUA bProcessed=TRUE;
7v-C-u[E` }
a5'QL(IX }
Cn,jLy }
MiC&av if(!bProcessed){
`#R$ for(int index=0;index<MAX_KEY;index++){
BXdT;b"J( if(hCallWnd[index]==NULL)
E|>I/!{u7` continue;
oI>;O# if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
;cO0Y.V9l SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
O/k4W# }
C.@zVt }
0h7\zoZ5 }
b &JPLUr return CallNextHookEx( hHook, nCode, wParam, lParam );
9$ _}E` }
+o/q@&v;Ax -X=f+4j BOOL InitHotkey()
;02lmpBj {
r=9*2X# if(hHook!=NULL){
78X;ZMY nHookCount++;
HZ|6&9we return TRUE;
+z4NxR
}
C{c (K! else
PXkPC%j hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
%:??QD* if(hHook!=NULL)
%pMW5]H nHookCount++;
y|@^0]}%< return (hHook!=NULL);
#*9*[Xbi }
}{lOsZA BOOL UnInit()
YFW+l~[# {
t*DM^.@ if(nHookCount>1){
=Xp3UNXg nHookCount--;
9@h>_1RJz return TRUE;
OxD\e5r }
7
724,+2N BOOL unhooked = UnhookWindowsHookEx(hHook);
H[Qh* pq2 if(unhooked==TRUE){
vOqYt42
nHookCount=0;
z` sH hHook=NULL;
tp1{)|pwY6 }
N%T-Q9k return unhooked;
kh`X92~ }
b~\![HoCMM (Q@m;i> BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
%TLAn[LW( {
!0w'S>e BOOL bAdded=FALSE;
K,So#Ui for(int index=0;index<MAX_KEY;index++){
XL+kEZ|3 if(hCallWnd[index]==0){
^ML2xh hCallWnd[index]=hWnd;
s#d>yx_b HotKey[index]=cKey;
e\P+R>i0 HotKeyMask[index]=cMask;
cd:O@)i bAdded=TRUE;
s6qe5[ KeyCount++;
NoPM!.RU{ break;
"r[Ea| }
d 5Il0sG }
87*R#(( return bAdded;
x[)S3UJ }
MxCs0::w p<jHUG4?' BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
l]%|w]i\ {
\f+R! BOOL bRemoved=FALSE;
A?_2@6Y^ for(int index=0;index<MAX_KEY;index++){
1Og9VG1^ if(hCallWnd[index]==hWnd){
<,LeFy\zW if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
,x_g|J _Y hCallWnd[index]=NULL;
6jKM,%l HotKey[index]=0;
Ron^PvvY& HotKeyMask[index]=0;
6k^vF~ bRemoved=TRUE;
{(t (}-:Z KeyCount--;
}3+q}_3 break;
X-t4irZ) }
l ='lV] }
PUa~Apj' }
AjZT- Q0L return bRemoved;
Cu!4ha.e` }
v}iJ:' L*FnFRhU void VerifyWindow()
60hf)er {
F.O2;M|x for(int i=0;i<MAX_KEY;i++){
jP+4'O!s[ if(hCallWnd
!=NULL){ \Z)'':},C
if(!IsWindow(hCallWnd)){ gs9f2t
hCallWnd=NULL; 2wu
5`Z[E
HotKey=0; rPQ$e!m1Ee
HotKeyMask=0; uZ
OUp8QQ
KeyCount--; SLBKXj|
} S>**hMU%
} 654PW9{(
} m
81\cg
} c5U1N&k5&
+K+
== mO&
BOOL CHookApp::InitInstance() @89mj{
{ QAu^]1 ;
AFX_MANAGE_STATE(AfxGetStaticModuleState()); 6Q\n<&,{
hins=AfxGetInstanceHandle(); L@v0C)
InitHotkey(); L9G=+T9
return CWinApp::InitInstance(); .}j@(D
} /x`H6'3?
qo'pU/@
int CHookApp::ExitInstance() v^KJU
+
{ &(wik#S
VerifyWindow(); #
VR}6Jv
UnInit(); Ih"f98lV
return CWinApp::ExitInstance(); *r(iegO$
} f *)t<1f
{_ Wtk@
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file >R.~'A/$F
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) rJZ-/]Xf!6
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ M~3(4,
#if _MSC_VER > 1000 ]>x674H
#pragma once zYH6+!VBH#
#endif // _MSC_VER > 1000 |" l
g4S%
{>5c,L$
class CCaptureDlg : public CDialog vW~_+:),e
{ bx`(d@
// Construction XjL( V1
public: ,![C8il,
BOOL bTray; \QYs(nm?k
BOOL bRegistered; M}us^t*
BOOL RegisterHotkey(); ?ILNp`k
UCHAR cKey; +}z
T][9w
UCHAR cMask; T*'5-WV|3t
void DeleteIcon(); +]UPY5:F
void AddIcon(); o1YhYA
UINT nCount; |RHX2sso
void SaveBmp(); .\<
\J|3
CCaptureDlg(CWnd* pParent = NULL); // standard constructor aiU n
bP
// Dialog Data ]_5C5m
//{{AFX_DATA(CCaptureDlg) TS@EE&W