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:
f*88k='\W
g.blDOmlc 一、实现方法
KHx;r@{< 5} <OB-9 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:
{QmK4(k?|c k%\y,b* #pragma data_seg("shareddata")
)F\kGe HHOOK hHook =NULL; //钩子句柄
fv+d3s?h UINT nHookCount =0; //挂接的程序数目
m\CU,9;;( static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
7lAJ
0 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
%Ie,J5g5 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
Y,yU460T8 static int KeyCount =0;
cTn(Tv9s static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
{q+gm1iC #pragma data_seg()
. XbDb N?#L{Yt 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。
t2.jg?`k 4 #KC\C 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:
\K}KnJ #*lDKn[vO BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
_D@QsQ_Z cKey,UCHAR cMask)
} _];yw {
Wd(|w8J{a BOOL bAdded=FALSE;
\fSruhD for(int index=0;index<MAX_KEY;index++){
vN@04a\h if(hCallWnd[index]==0){
N+5f.c+S- hCallWnd[index]=hWnd;
{R[ V HotKey[index]=cKey;
RhT:] HotKeyMask[index]=cMask;
=h=-&DSA bAdded=TRUE;
=B'Yx KeyCount++;
8'zfq
]g break;
&U=_:]/ }
#nft{AN }
-kP2Brm return bAdded;
9-&@Y }
.YH#+T' //删除热键
{|j-e{* BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
$AvaOI.l {
p`Tl)[* BOOL bRemoved=FALSE;
Y#-c<o}f for(int index=0;index<MAX_KEY;index++){
`('Up? if(hCallWnd[index]==hWnd){
Au/'|%2#( if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
\>EUa}%xn hCallWnd[index]=NULL;
g2}aEfp!H HotKey[index]=0;
v;g,qO!LJ HotKeyMask[index]=0;
qzHsqlof bRemoved=TRUE;
J8@+)hn KeyCount--;
`:m=rT_ break;
QkTU@T6>o }
[I'q"yRu]i }
!Q%r4Nr
}
z Z~t,> return bRemoved;
l
ObY }
-;HZ!Lf =z<sx2#* `'mRGz7t DLL中的钩子函数如下:
v$q\3#5|' .{bT9Sc5 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
s2 aFme {
i? #U>0! BOOL bProcessed=FALSE;
I{H!KrM! if(HC_ACTION==nCode)
&Q\k`0vzVB {
[Q6$$z92Q if((lParam&0xc0000000)==0xc0000000){// 有键松开
H.l
WHM+H4 switch(wParam)
Po\+zZjo {
8(A
k case VK_MENU:
w)YTHY(k; MaskBits&=~ALTBIT;
&?y|Pn break;
|\"%Dy[m case VK_CONTROL:
\MmB+'f&R MaskBits&=~CTRLBIT;
\Km+>G break;
7<2?NLE8* case VK_SHIFT:
eCg|@d% D MaskBits&=~SHIFTBIT;
lD_iIe~c break;
kZ:~m1dd default: //judge the key and send message
|qf9-36 break;
*l0i}"T^_ }
GIR12%-EO for(int index=0;index<MAX_KEY;index++){
1.~^QH\p?3 if(hCallWnd[index]==NULL)
.>y3`,0h continue;
+_f813$C if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Bv%dy[I {
jlUT9Zp SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
s <$*A;t bProcessed=TRUE;
qe0ZM-C_ }
'=(yh{W }
)D]LPCd[ }
5:EE%(g9 else if((lParam&0xc000ffff)==1){ //有键按下
0d`lugf switch(wParam)
aKRnj!4z {
Pb@$RAU63 case VK_MENU:
;D[I/U MaskBits|=ALTBIT;
(t,|FkVLV break;
MpIP)bdq7 case VK_CONTROL:
IY2f$YV MaskBits|=CTRLBIT;
5hAs/i9_ break;
tf9a- s case VK_SHIFT:
9w\C
vO&R MaskBits|=SHIFTBIT;
+J}h break;
#so"p<7 R default: //judge the key and send message
J+hifO break;
z KG]7 }
gvP.\,U for(int index=0;index<MAX_KEY;index++){
^c sOXP=Yp if(hCallWnd[index]==NULL)
8Y;>3zth7 continue;
,/Y$%.Rp if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
_9iF`Q {
R_:-Z.
SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
h#|A c>fz bProcessed=TRUE;
sNC~S%[ }
VOp+6ho< }
ve(@=MJ }
-PiZvge if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
lJ4/bL2I/ for(int index=0;index<MAX_KEY;index++){
lstnxi%x if(hCallWnd[index]==NULL)
>LEp EMJ\ continue;
S?~/
V ] if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
7{f{SIB SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
(*!4O>] //lParam的意义可看MSDN中WM_KEYDOWN部分
:Ui'x8yt }
Lez]{%+.`[ }
KVpQ,x&q~ }
8RVeKnpXTV return CallNextHookEx( hHook, nCode, wParam, lParam );
.ldBl }
piPV&ytI Jqt|'G3 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:
NX<Q}3cC 7)Bizlf BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
Yp9%u9tNq BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
_qS4Ns/4s .OF2O} 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:
`%0k\,}V 8uetv LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
,aSK L1 {
sRGIHT# if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
V"sm+0J {
5U JMiwP{ //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
<d3N2 SaveBmp();
(_~Dyvo return FALSE;
"eKM<S }
BH?fFe&J:` …… //其它处理及默认处理
K%>3ev=y.s }
p{rzP,Pb& *3!ixDX[r 4=hz4(5a 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。
YR68'Sft[ GG`;c?d@ 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。
=xHzhh 7C^W <SUo 二、编程步骤
'\B!1B>T +}!FP3KgT 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";
AaJnRtBS~ xy<)zKp 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
\F),SL Cv1CRmqq% 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;
_VAX~Y] ltG|#( 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;
k|_LF[* Z ^9*Jz{e 5、 添加代码,编译运行程序。
?rububDT{ nA XWbavY 三、程序代码
@?<1~/sfL 7.1FRxS ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
)m$i``*<
#if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
C]%}L%, #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
o_%gFV[q #if _MSC_VER > 1000
qu0dWgK #pragma once
q8fnUK?i #endif // _MSC_VER > 1000
G!m;J8#m( #ifndef __AFXWIN_H__
`v1~nNoY #error include 'stdafx.h' before including this file for PCH
{DGnh1 #endif
+K*_=gHF. #include "resource.h" // main symbols
{FNq&)#` class CHookApp : public CWinApp
r*4@S~; {
[5jXYqD=vj public:
$t42?Z=N&z CHookApp();
eop7=!`-~~ // Overrides
C2Af$7c // ClassWizard generated virtual function overrides
cP (is! //{{AFX_VIRTUAL(CHookApp)
tY$4k26 public:
}h_=
n> virtual BOOL InitInstance();
'9q:gFO virtual int ExitInstance();
|th"ET //}}AFX_VIRTUAL
,L7:3W //{{AFX_MSG(CHookApp)
*v9 {f? // NOTE - the ClassWizard will add and remove member functions here.
Eg|C // DO NOT EDIT what you see in these blocks of generated code !
ZuQ\Pyx //}}AFX_MSG
W&Gt^5 DECLARE_MESSAGE_MAP()
&Kc'g H };
/kK:{ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
Hqm1[G) BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
BvV!?DY4 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
)qV&sru.$ BOOL InitHotkey();
LDv>hzo BOOL UnInit();
)1S"D~j- #endif
\{M/Do: 5Gsjt+
o //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
[+Y;w`;Fq #include "stdafx.h"
SB2Ij', #include "hook.h"
e`D? x1- #include <windowsx.h>
/2e,,)4g #ifdef _DEBUG
dW>$C_`? #define new DEBUG_NEW
;tu2}1#r #undef THIS_FILE
?>o|H-R~5Z static char THIS_FILE[] = __FILE__;
+c_8~C #endif
[}bPkD #define MAX_KEY 100
7FD.3/ #define CTRLBIT 0x04
Luu.p< #define ALTBIT 0x02
DANndXQLH #define SHIFTBIT 0x01
66s h r #pragma data_seg("shareddata")
,2_!hm/ HHOOK hHook =NULL;
@je vY81) UINT nHookCount =0;
%oEvp{I static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
x$\w^h\F static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
h|t\rV^ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
-z$&lP] static int KeyCount =0;
#^oF^! static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
(qXl=e8 #pragma data_seg()
&C7HG^;W9 HINSTANCE hins;
rCdf*; void VerifyWindow();
bv8GJ # BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
>On"BP# U //{{AFX_MSG_MAP(CHookApp)
Ks-aJ+} // NOTE - the ClassWizard will add and remove mapping macros here.
v&*}O // DO NOT EDIT what you see in these blocks of generated code!
%R[X_n= //}}AFX_MSG_MAP
9,zM.g9Qv END_MESSAGE_MAP()
K+s
xO/}h t.E3Fh!o CHookApp::CHookApp()
=)Q0=!%- {
Fq9>t/Zj // TODO: add construction code here,
;0`p"T0 // Place all significant initialization in InitInstance
@s@67\ }
5.e.
BT 9K`uGu CHookApp theApp;
!~~j&+hK\ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
gC qQ~lWZ {
Jf=$h20x BOOL bProcessed=FALSE;
nzK"eNDN. if(HC_ACTION==nCode)
3?R QPP {
:},/D*v if((lParam&0xc0000000)==0xc0000000){// Key up
.JkF{&=B switch(wParam)
|]9Z#lv+I {
YKsc[~
h case VK_MENU:
&,B91H*# MaskBits&=~ALTBIT;
>ey-j\_v break;
!,3U_! case VK_CONTROL:
lm;G8IP` MaskBits&=~CTRLBIT;
~
U,a?LR/ break;
kwd)5J case VK_SHIFT:
h*GU7<F:a MaskBits&=~SHIFTBIT;
Z'I0e9Jw break;
!p~K;p, default: //judge the key and send message
L7lRh=D break;
E[RLBO[*n }
a\PvRW*I for(int index=0;index<MAX_KEY;index++){
M :Aik& if(hCallWnd[index]==NULL)
JKsdPW<? continue;
d4#Ra% if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
d@72z r {
^BFD -p SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
0fTEb%z8 bProcessed=TRUE;
!bi}9w }
dnP3{!"b }
on q~wEr }
cOr@dUSL else if((lParam&0xc000ffff)==1){ //Key down
SAEV " switch(wParam)
32sb$|eQq {
KVrK:W--p case VK_MENU:
s *B-| MaskBits|=ALTBIT;
Kc:}
K y break;
%g>{m2o case VK_CONTROL:
PNbs7f MaskBits|=CTRLBIT;
f1RfNiW. break;
!B3lsXLSY case VK_SHIFT:
hoQ?8}r: MaskBits|=SHIFTBIT;
#`0iN+qh break;
fii\&p7z default: //judge the key and send message
Dy[
YL break;
F^]?'`7md }
cs%NsnZ for(int index=0;index<MAX_KEY;index++)
'0xJp|[xVP {
(Q$]X5L if(hCallWnd[index]==NULL)
}bs2Rxkh continue;
cCj pQ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
A<&:-Zz {
E+&]96*Lby SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
ewn/@;E bProcessed=TRUE;
|UO1v A@ }
,A>i)brc }
ZREAEGi{ }
~"*;lT5KX if(!bProcessed){
B43o_H|s for(int index=0;index<MAX_KEY;index++){
r]=3aebR. if(hCallWnd[index]==NULL)
j{nkus2 continue;
kPVP+}cA if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
.F~EQ % SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
cg,_nG]i }
}<wj~f([ }
|7CH }
KcB?[ return CallNextHookEx( hHook, nCode, wParam, lParam );
a`w)awb }
uxto:6),P< 3\,TI`^C BOOL InitHotkey()
L?^C\g6u] {
8<g_JW[% if(hHook!=NULL){
C%P"Ds=w0N nHookCount++;
hfvs'. return TRUE;
e;=G|E }
b* 6c.
else
NRKAEf_#w hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
uREc9z`Q' if(hHook!=NULL)
~P5!VNJ;r nHookCount++;
Ej1 [ry return (hHook!=NULL);
VmTk4?V4 }
|jV4]7Luq BOOL UnInit()
dBG]J18 {
<C4^Vem if(nHookCount>1){
X/1Z9a+W nHookCount--;
<EI'N0~KG return TRUE;
T
T0O % }
IEzZ$9,A5 BOOL unhooked = UnhookWindowsHookEx(hHook);
<MN+2^ed& if(unhooked==TRUE){
e<^tY0rR& nHookCount=0;
0nAeeVz| hHook=NULL;
Iw"?%k\U }
}}qR~.[ return unhooked;
8I C(( }
nm'm*sU\ @D"1}CW BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
S$"A[ {
7$GP#V1r/ BOOL bAdded=FALSE;
@fpxGMy& for(int index=0;index<MAX_KEY;index++){
YKh%`Y1< if(hCallWnd[index]==0){
O)5-6lm hCallWnd[index]=hWnd;
!00%z HotKey[index]=cKey;
,XP9NHE HotKeyMask[index]=cMask;
Pr<?E[ bAdded=TRUE;
:B- ,*@EU KeyCount++;
{uj9fE,) break;
j)F~C8* }
%h%r6EB1F }
Ro:-u7q return bAdded;
S0=BfkHi. }
*OF7{^~& 4r(rWlM BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
]Ly)%a32 {
'd?8OV BOOL bRemoved=FALSE;
PfrW,R~r for(int index=0;index<MAX_KEY;index++){
y i@61XI if(hCallWnd[index]==hWnd){
dl{3fldb if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
L761m7J]B hCallWnd[index]=NULL;
lQ+-g#` HotKey[index]=0;
>5 5/@+^ HotKeyMask[index]=0;
Q)a*bPz bRemoved=TRUE;
*pasI.2s# KeyCount--;
N=+Up\h break;
1 *-58N* }
QW2% Gv: }
\iVYhl }
1<R
\V return bRemoved;
w\t{' }
&2\.6rb. nMc-kyl{ void VerifyWindow()
_F3vC# {
Pq4sv`q)S for(int i=0;i<MAX_KEY;i++){
SyYa_=En if(hCallWnd
!=NULL){ _ve7Is`/
if(!IsWindow(hCallWnd)){ -`?V8OwY]
hCallWnd=NULL; d'-^VxO0
HotKey=0; Dkdm~~Rr
HotKeyMask=0; \aW5V: ?
KeyCount--; Hh@mIusj
} ac&tpvij
} 2=3iA09px
} L:^'cl}
G
} Vk_L*lcN
(~#PzE:
BOOL CHookApp::InitInstance() zu|pL`X
{ ng 6G<hi
AFX_MANAGE_STATE(AfxGetStaticModuleState()); /r?X33D!
hins=AfxGetInstanceHandle(); E{Q^ZSV3B
InitHotkey(); fg1 zT~
return CWinApp::InitInstance(); =q"3a9pb7
} Ahebr{u
X>wQYIi
int CHookApp::ExitInstance() JqZ%*^O
{ ?4~lA
L1
VerifyWindow(); LQQhn{[D
UnInit(); tIvtiN6[|l
return CWinApp::ExitInstance(); TM RXl.1
} "M*\,IH
)t.q[O`
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file kdo)y(fn@
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) . }1!MK5
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ BW*zj=N%
#if _MSC_VER > 1000 }gn0bCJy
#pragma once -FPl",f=r
#endif // _MSC_VER > 1000 +<|w|c
B=p'2lla
class CCaptureDlg : public CDialog ><DE1tG
{ a[JgR /E@x
// Construction P~*fZ)\}F@
public: qj/P4 *6E
BOOL bTray; ~\_E%NR
yA
BOOL bRegistered; :dj@i6
BOOL RegisterHotkey(); 1 h"B-x
UCHAR cKey;
~.Gk:M
UCHAR cMask; ~lL($rE
void DeleteIcon(); %$}iM<
void AddIcon(); qy]-YJZ
UINT nCount; b13>>'BMB
void SaveBmp(); #*`|}_6L
CCaptureDlg(CWnd* pParent = NULL); // standard constructor 8_LDS
// Dialog Data bC{~/ JP
//{{AFX_DATA(CCaptureDlg) ?:2Xh/8-
enum { IDD = IDD_CAPTURE_DIALOG }; uJ$"2<O
CComboBox m_Key; SW=p5@Hy{
BOOL m_bControl; z(=:J_N
BOOL m_bAlt; =wQ=`
BOOL m_bShift; %SE g(<