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:
q+2A>:|
pzaU'y#PM 一、实现方法
s:_a.4&Y wwQ2\2w>Hm 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:
NHe)$%a=H byMy-v; #pragma data_seg("shareddata")
)l.uj HHOOK hHook =NULL; //钩子句柄
*j,bI Y&se UINT nHookCount =0; //挂接的程序数目
)=`DEbT static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
`'>~(8&zE static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
R
eb.x_ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
Q1ayd$W@< static int KeyCount =0;
<mj/P|P@ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
lpS v #pragma data_seg()
6VuyKt ,>za|y<n 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。
}0Uh<v@ /8nUecr 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>iXNwz"? 1P'A*`!K BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
'Bxj(LaV- cKey,UCHAR cMask)
0
f$96sl {
G
9(*F BOOL bAdded=FALSE;
JtsXMZz for(int index=0;index<MAX_KEY;index++){
R4P&r=? if(hCallWnd[index]==0){
>)G[ww[ hCallWnd[index]=hWnd;
YllZ5<} HotKey[index]=cKey;
MkjB4:" HotKeyMask[index]=cMask;
"'@D\e} bAdded=TRUE;
7Z~JuTIZ KeyCount++;
*9xxX,QT8Q break;
<2L,+ }
%{pjC7j# }
68(^* return bAdded;
023uAaI^3r }
~d1=_p:~T //删除热键
x X[WX#'f BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
TJZ/lJU {
VzIZT{ BOOL bRemoved=FALSE;
\8m9^Z7IfK for(int index=0;index<MAX_KEY;index++){
8x LXXB if(hCallWnd[index]==hWnd){
x}Lj|U$r<X if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
<
W`gfpzO hCallWnd[index]=NULL;
pL}
F{G. HotKey[index]=0;
g|->W]q@; HotKeyMask[index]=0;
J~4mp\4b bRemoved=TRUE;
-mGG:#yP KeyCount--;
0l& '` break;
9<toDg_ }
<DPRQhNW] }
jkta]#O }
TC44*BHq return bRemoved;
B!;:,(S~ }
r_T"b r@]`#PL ,x!r^YO= DLL中的钩子函数如下:
DpeJx rXT? w]4 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
y N9~/g {
MRK=\qjD
BOOL bProcessed=FALSE;
1gcWw, / if(HC_ACTION==nCode)
6-tIe_5 {
zPybPE8 if((lParam&0xc0000000)==0xc0000000){// 有键松开
j~V$q/7S switch(wParam)
l2YClK {
@mv
G=:k case VK_MENU:
kksffzG MaskBits&=~ALTBIT;
Ejr'Yzl3_ break;
/kK!xe case VK_CONTROL:
q~5zv4NX MaskBits&=~CTRLBIT;
bZ:+q1
D break;
*PV7s case VK_SHIFT:
\`["IkSg7 MaskBits&=~SHIFTBIT;
X>Q4 4FV! break;
K(PSGlI f default: //judge the key and send message
]!P8 {xmb@ break;
S]|sKY }
"S6";G^I for(int index=0;index<MAX_KEY;index++){
V|B4lGS& if(hCallWnd[index]==NULL)
64mD%URT continue;
OIpT9 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
\'[tfSB {
Ii5U)" SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
!sEhjJV^7 bProcessed=TRUE;
1 I.P7_/ }
~Ey+ }
FXn98UF Y }
8Dtpb7\o else if((lParam&0xc000ffff)==1){ //有键按下
r-L& ee switch(wParam)
L@=$0p41; {
#Y3-P case VK_MENU:
F=w:!tqA MaskBits|=ALTBIT;
kZ)}tA7j break;
_deEs5i case VK_CONTROL:
,dK)I1"C MaskBits|=CTRLBIT;
@RszPH1B break;
, .~k case VK_SHIFT:
pjTJZhT2 I MaskBits|=SHIFTBIT;
gp{C89gP break;
SiaW; ks default: //judge the key and send message
/5"T46jD break;
.K(9=yh }
vY|YqWt for(int index=0;index<MAX_KEY;index++){
H
lM7^3(& if(hCallWnd[index]==NULL)
~Js kA5h|& continue;
mVYfyLZ,( if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
*c=vEQn- {
f(blqO.@l SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
<]KQ$8dtD bProcessed=TRUE;
cLwnV. }
mI DVN }
<fDT/ }
^0cbN[~/ns if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
D_JGbNigA for(int index=0;index<MAX_KEY;index++){
{47l1wV] if(hCallWnd[index]==NULL)
EK[J!~ continue;
4lc|~Fj++ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
%`T}%B SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
chUYLX}45 //lParam的意义可看MSDN中WM_KEYDOWN部分
!03JA 9lo }
;L -)$Dy4 }
WwZ3hd }
s$fX
; return CallNextHookEx( hHook, nCode, wParam, lParam );
{5{VGAD&]> }
na~ FT[3C Me?I8:/ 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:
k[D,du') jVN06,3z BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
NQ[X=a8N BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
ZYY2pY 1 P*7G? 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:
YZ8[h`z >K4Nn(~ys LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
0&I*)Zt9x {
Ly^bP>2i if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
)D/,QWk {
52Lp_M //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
%Gyn.9\ SaveBmp();
l=l$9H, return FALSE;
6s~B2t:Y }
dm=?o …… //其它处理及默认处理
r"{jrBK$ }
8UgogNR\ "]q
xjs^3? ^<cJ;u*0 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。
o/VT"cT Z:N;>.3i 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。
aZ_3@I{d` aN07\ 二、编程步骤
lkJxb~S ,K\7y2/ 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";
%]0?vw:;j et)n`NlcK 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
TB.>?*<n] - QY<o| 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;
W]7<PL*u i \/'w] 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;
1_f+!
ns# NNqvjM- 5、 添加代码,编译运行程序。
k,=<G, ]N'%l]_$ 三、程序代码
m3pDFI W3>9GY90R ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
V-go?b` #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
F09%f"9 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
"h[)5V{ #if _MSC_VER > 1000
1`L.$T,1! #pragma once
$"|r7n5[ #endif // _MSC_VER > 1000
5m0lk|` #ifndef __AFXWIN_H__
1~~GF_l? #error include 'stdafx.h' before including this file for PCH
=_C&lc" #endif
5j ]!r #include "resource.h" // main symbols
pQ0*)}l, class CHookApp : public CWinApp
yUo8-O aL7 {
G93V=Bk= public:
YQHpW>z CHookApp();
a5ZXrWv // Overrides
?uL-qsU // ClassWizard generated virtual function overrides
H.;}%id //{{AFX_VIRTUAL(CHookApp)
3ddw'b'aQ public:
Wj|W B*B virtual BOOL InitInstance();
=0EKrG virtual int ExitInstance();
9,_~qWw //}}AFX_VIRTUAL
S g1[p#U //{{AFX_MSG(CHookApp)
Bi
\fB-| // NOTE - the ClassWizard will add and remove member functions here.
[s]$& // DO NOT EDIT what you see in these blocks of generated code !
:fL7"\
pf~ //}}AFX_MSG
K.wRz/M&g DECLARE_MESSAGE_MAP()
zGg)R };
#\Y`? LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
>%92,hg BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
H^S<bZ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
:P2!& W BOOL InitHotkey();
<^5$))r BOOL UnInit();
NI,>$@{ #endif
8[X"XThj 9%NsW3| //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
yeta)@nH #include "stdafx.h"
Un)Xe #include "hook.h"
Yq|_6zbYf #include <windowsx.h>
S{&%tj~U #ifdef _DEBUG
hO.b?>3NL #define new DEBUG_NEW
Fy E#@ R #undef THIS_FILE
xsRkO9x static char THIS_FILE[] = __FILE__;
+3zQ"lLD^ #endif
[DeDU: #define MAX_KEY 100
N]iarYc #define CTRLBIT 0x04
Q) aZ0 Pt #define ALTBIT 0x02
B%Qo6*b #define SHIFTBIT 0x01
EU:N9oT #pragma data_seg("shareddata")
ub>:dNBN HHOOK hHook =NULL;
>/4[OPB0R UINT nHookCount =0;
#V/{DPz static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
5ta;C G static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
0F- +)S?M[ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
Uq'W<.v5 static int KeyCount =0;
S{e3aqT#N static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
3zKeN:w #pragma data_seg()
wt9f2 HINSTANCE hins;
iZnLgkk@ void VerifyWindow();
Jv3G\9_ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
Gchs$^1`t //{{AFX_MSG_MAP(CHookApp)
1U/9=b // NOTE - the ClassWizard will add and remove mapping macros here.
qP;1LAX // DO NOT EDIT what you see in these blocks of generated code!
RZ{O6~VH //}}AFX_MSG_MAP
4FYV]p8f END_MESSAGE_MAP()
L#a!fd )O+Zbn CHookApp::CHookApp()
R|)l^~x {
ZoJqJWsd // TODO: add construction code here,
! })Y9oZc8 // Place all significant initialization in InitInstance
-:=m-3*Tg }
|+HJ>xA4I 7z3tDE[# CHookApp theApp;
!'#
D~ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
sDg1nKw( {
`0U\|I# BOOL bProcessed=FALSE;
WO%pX+PoH if(HC_ACTION==nCode)
F?a
63,r {
"pK<d~Wu if((lParam&0xc0000000)==0xc0000000){// Key up
0!%G#~th switch(wParam)
%?+Lkj& {
0%&}w UjV case VK_MENU:
)XSHKPTQ1 MaskBits&=~ALTBIT;
(c}!gjm break;
yLCMu | + case VK_CONTROL:
Dl0{pGK~ MaskBits&=~CTRLBIT;
\DE,
, break;
C"5P7F{ case VK_SHIFT:
fHZ9wK> MaskBits&=~SHIFTBIT;
i qxMTH#! break;
xa]yq% default: //judge the key and send message
yId1J break;
_fn7-&6 }
&gT@oS{ for(int index=0;index<MAX_KEY;index++){
>JA-G@3i if(hCallWnd[index]==NULL)
|LLpG37_ continue;
:!CnGKgt if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
#=)>,6Zw {
8,h!&9 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
29G el bProcessed=TRUE;
n
ei0LAD }
/=za
m3kd }
K0v S }
Ici4y*`M else if((lParam&0xc000ffff)==1){ //Key down
7;TMxO=bra switch(wParam)
~};q/-[r {
WY@g=W>+ case VK_MENU:
{0,6-dd5 MaskBits|=ALTBIT;
sx7zRw
>X break;
T3=h7a %= case VK_CONTROL:
L;?h)8 MaskBits|=CTRLBIT;
]57Ef'N break;
w1zMY:9 case VK_SHIFT:
sxuP"4 MaskBits|=SHIFTBIT;
%o\+R0K break;
WB'1_a default: //judge the key and send message
{=d}04i)E" break;
x.pg3mVd> }
J1gnR for(int index=0;index<MAX_KEY;index++)
$A,YQH+ {
i E;F=Rb if(hCallWnd[index]==NULL)
oVp/EQ continue;
8#,_%<?UVy if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Au)~"N~p? {
`wj' SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
M(\{U"%@? bProcessed=TRUE;
|XQ_4{ }
s}UJv\* }
QAo/d4 }
u~FVI if(!bProcessed){
?9eiT:2 for(int index=0;index<MAX_KEY;index++){
zNo"P[J8 if(hCallWnd[index]==NULL)
%{V7|Azt continue;
#Q=c.AL{ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Qof%j@ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
RSB+Saf.8 }
bxO/FrwTj{ }
hCgk78O? }
4=y&}3om(0 return CallNextHookEx( hHook, nCode, wParam, lParam );
as/PM" }
_~umE/tz `h :!^"G BOOL InitHotkey()
2Rwd\e.z {
`) ],FE*: if(hHook!=NULL){
2(\PsN w! nHookCount++;
E&t8nlTx return TRUE;
Fx1FxwIJ }
E^{!B]/oP else
*+6iXMwe hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
Zi\ex\ )5 if(hHook!=NULL)
>y#qn9rV1 nHookCount++;
csJ)Pt?d return (hHook!=NULL);
~W4SFp }
c,)]!{c BOOL UnInit()
2$t%2>1>@ {
y>h9:q| if(nHookCount>1){
pNQ7uy nHookCount--;
/D|q-`*K return TRUE;
s]A8C^;c }
[%6) BOOL unhooked = UnhookWindowsHookEx(hHook);
5f0g7w =- if(unhooked==TRUE){
#M#$2Vt nHookCount=0;
hHDLrr hHook=NULL;
bJ6C7-w:wa }
Q;q{1M > return unhooked;
?D9iCP~~ }
hG<[F@d -nUK%a"(D BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
b-@9Xjv {
Lq.2vfA> BOOL bAdded=FALSE;
8sI$ for(int index=0;index<MAX_KEY;index++){
XMP4YWuVc if(hCallWnd[index]==0){
_p9"MU&} hCallWnd[index]=hWnd;
Xnh&Kyz`v HotKey[index]=cKey;
^PJN$BJx HotKeyMask[index]=cMask;
_):@C:6 bAdded=TRUE;
GCw4sb4~w KeyCount++;
0SIUp/. break;
{<}Hut:a }
\WdSj }
c`S+>: return bAdded;
v,~fG>Y} }
+`mI\+y, 2Ir*}s2{ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
e$Yvy>I'tS {
G^VOA4 BOOL bRemoved=FALSE;
bF,.6iKI for(int index=0;index<MAX_KEY;index++){
F9las#\J if(hCallWnd[index]==hWnd){
-U9C{q?h if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ku}`PS0UGd hCallWnd[index]=NULL;
o>yXEg HotKey[index]=0;
MwQt/Qv= HotKeyMask[index]=0;
d,
?GW bRemoved=TRUE;
# SJJ@SM KeyCount--;
_"t>72
`
break;
cCx{
") }
,-(D(J;}1 }
A yn$, }
NZ!I > return bRemoved;
1#+|RL4o }
./'d^9{ eMV8`&c' void VerifyWindow()
"j8=%J{ {
r>*+d|c4 for(int i=0;i<MAX_KEY;i++){
HmU6:8V
*Z if(hCallWnd
!=NULL){ #D{Eq8dp
if(!IsWindow(hCallWnd)){ 9Nv?j=*$
hCallWnd=NULL; X$P(8'[9A
HotKey=0; [[N${ C
HotKeyMask=0; %" l;
KeyCount--; o#z$LT1dY
} lt2MB#
} xA-?pLt"G
} i!RYrae
} GGhk`z
S^EAE]
BOOL CHookApp::InitInstance() rb'mFqg*u
{ eq&QWxiD*
AFX_MANAGE_STATE(AfxGetStaticModuleState()); @}{uibLD\
hins=AfxGetInstanceHandle(); .O#7X
InitHotkey(); w?N>3`Jnf
return CWinApp::InitInstance(); ,PJC FQMR
} )4:]gx#cr
+IjBeQ?
int CHookApp::ExitInstance() M ]O4
{ Q uw|KL
VerifyWindow(); G'dN<Nw6
UnInit(); :mf&,?
return CWinApp::ExitInstance(); BxQ,T@
} u.?jW vcv
3qH1\
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file O1DUBRli!q
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) yxf#@Je"
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ $bZ-b1{c C
#if _MSC_VER > 1000 4UzXTsjM7
#pragma once E:A!tu$B
#endif // _MSC_VER > 1000 N{@~(>ee^
B/n~ $
class CCaptureDlg : public CDialog \M0's&