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:
n:/!{.
v/rBjUc+X 一、实现方法
\L~^c1s3r $ MH;v_'a 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:
s)]T"87H'_ x
cAs}y} #pragma data_seg("shareddata")
7AT8QC`u HHOOK hHook =NULL; //钩子句柄
qKd ="PR} UINT nHookCount =0; //挂接的程序数目
.G\](% static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
4sQm"XgE static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
5wx~QV=Hh static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
57{T
p:| static int KeyCount =0;
"Ux(nt static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
U?f-/@fc #pragma data_seg()
)2Sh oFF <#?dPDMG.* 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。
r/AOgS [>a3` 0M 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:
PbZ%[F 0*5Jq#5 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
NN'pBUR cKey,UCHAR cMask)
q C cLd7`$ {
ddKP3} BOOL bAdded=FALSE;
F<p`)? for(int index=0;index<MAX_KEY;index++){
"A+7G5 if(hCallWnd[index]==0){
|}:}14ty hCallWnd[index]=hWnd;
mm+V*L{x HotKey[index]=cKey;
"i#g [x HotKeyMask[index]=cMask;
jXf@JxQ bAdded=TRUE;
K1J |\!o KeyCount++;
IKP_%R8. break;
])F+ C/Px1 }
.lb]Xa*n }
sS
?A<D return bAdded;
=Mwuhk|* }
f?/OV * //删除热键
#2U# h-vI BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
{f`Y\_r$@ {
}WFI/W' BOOL bRemoved=FALSE;
hzM;{g>t for(int index=0;index<MAX_KEY;index++){
2qE_SSXn if(hCallWnd[index]==hWnd){
O D N_i if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Yz0fOX hCallWnd[index]=NULL;
!J;Bm,Xn6 HotKey[index]=0;
ck0%H#BYY HotKeyMask[index]=0;
D1-/#QN$1 bRemoved=TRUE;
TPBQfp%HU KeyCount--;
J i@q7qkC break;
?:`sE" }
ps2j ]g }
bR"4:b>K }
:]F66dh+ return bRemoved;
a_}C*+D }
\K\eq>@6 R7(XDX=[s &PV%=/-J DLL中的钩子函数如下:
N#9N ^#1 a+lNXlh= LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
%$zak@3%' {
;5X~"#%U_ BOOL bProcessed=FALSE;
AFL'Ox]0 if(HC_ACTION==nCode)
t^MTR6y+8 {
p%*s3E1.D if((lParam&0xc0000000)==0xc0000000){// 有键松开
&AxtSIpucP switch(wParam)
W"@'}y {
"ADI. case VK_MENU:
tM\BO0 MaskBits&=~ALTBIT;
w?u3e+ break;
7W SP0Xyz case VK_CONTROL:
xF3FY0U[ MaskBits&=~CTRLBIT;
H%l-@::+$ break;
iNkN'(" case VK_SHIFT:
zMp vS rc MaskBits&=~SHIFTBIT;
_XP}fx7$C break;
CB>W# P% default: //judge the key and send message
X(E`cH
| break;
[[T6X9 }
Kh=\YN\E< for(int index=0;index<MAX_KEY;index++){
c0e[vrP: if(hCallWnd[index]==NULL)
|) ~-Wy continue;
z0\
$#r^I if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
9C?SEbC {
e^@ZN9qQ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
V /\Y(Mxc bProcessed=TRUE;
$s1/Rmw }
'")'h }
uHacu<$= }
yy/'B:g else if((lParam&0xc000ffff)==1){ //有键按下
0OG
3#pE switch(wParam)
40
u
tmC {
V[%IU'{: case VK_MENU:
o8:9Yjs MaskBits|=ALTBIT;
))dqC l break;
E71H=C 4 case VK_CONTROL:
*wx%jbJo MaskBits|=CTRLBIT;
/,~]1&?}1 break;
aUa+]H[ case VK_SHIFT:
QPp31o.!5 MaskBits|=SHIFTBIT;
sF :pwI5^ break;
UzSDXhzObf default: //judge the key and send message
=os!^{p7> break;
@b 17jmq{ }
J3 oUtu for(int index=0;index<MAX_KEY;index++){
o@
^^;30 if(hCallWnd[index]==NULL)
EGv]K| continue;
9i_@3OVl if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
IY!.j5q8 {
5IzCQqOPgX SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
mPPB"uQ bProcessed=TRUE;
PmsZ=FY }
1xkk5\3] }
9+ve0P7$ }
Sa)L=5Nr if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
sng6U;Z for(int index=0;index<MAX_KEY;index++){
IAb.Z+ig if(hCallWnd[index]==NULL)
c"CR_ continue;
i,RbIZnJ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
JY:Fu SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
sT iFh"8d> //lParam的意义可看MSDN中WM_KEYDOWN部分
vP'!&} }
s^)(.e_ }
%>zG;4 }
&l`_D?{<# return CallNextHookEx( hHook, nCode, wParam, lParam );
:ba4E[@ }
AGwdM-$iT 2XUIC^<@s 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
lxD~l#)^ln _E0yzkS BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
2C"i2/NH' BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
]CU)#X<J [zP}G?( 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
LoJEchRK "tmu23xQ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
.;bU["fn) {
b/T k$& if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
pXQ$n:e {
(yEU9R$I" //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
71<4q{n SaveBmp();
tmoclK- return FALSE;
?a,`{1m0\ }
?)Gb= …… //其它处理及默认处理
%qrUP\rn }
GX.a!XQ@! n
sN n>{ nC$c.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。
=(c.8d -~~R?,H'Z_ 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。
U
CFw+ $_a/!)bP 二、编程步骤
8ce'G"
b \:JY[s/ 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
"K|':3n| Bbb":c6w0 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
:$X dR:f}} K`|V1L.m 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;
\\oa[nvL~ _S &6XNV 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;
F5UHkv"K&O [
f<g?w 5、 添加代码,编译运行程序。
4w 7vgB .",BLuce 三、程序代码
b?M. 0{"H D iHj!tZN ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
^h`rA"F\ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
Hp(41Eb, #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
:q2RgZE #if _MSC_VER > 1000
:.-KM7tDI1 #pragma once
L&5zr_ #endif // _MSC_VER > 1000
m+pK,D~{" #ifndef __AFXWIN_H__
WdJeh:h #error include 'stdafx.h' before including this file for PCH
?WS.RB e2 #endif
3c` #include "resource.h" // main symbols
mxc^IRj class CHookApp : public CWinApp
Z0V6cikW6 {
54s90 public:
6l"4F6 CHookApp();
@'J~(#} // Overrides
tg%Sn+: // ClassWizard generated virtual function overrides
O15~\8#' //{{AFX_VIRTUAL(CHookApp)
&MONg=s3 public:
p .~5k virtual BOOL InitInstance();
`Y '-2Fv virtual int ExitInstance();
$iH //}}AFX_VIRTUAL
4;IZ}9|G //{{AFX_MSG(CHookApp)
>;xkiO>Y // NOTE - the ClassWizard will add and remove member functions here.
!0X"^VB // DO NOT EDIT what you see in these blocks of generated code !
K_X(j$2Xc //}}AFX_MSG
jfa<32`0E DECLARE_MESSAGE_MAP()
94rx4"AN8; };
N45@)s!F9j LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
uE#i3(
J BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
8rz,MsFR BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
f[OJqk BOOL InitHotkey();
FT gt$I BOOL UnInit();
)Z:maz #endif
MLDAr dvK Zc9S[ivq //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
eQ#"-i #include "stdafx.h"
LXc;`] #include "hook.h"
_ UF'Cf+Y #include <windowsx.h>
kRiZ6mn #ifdef _DEBUG
$yFR{_] #define new DEBUG_NEW
Ojp|/yd^YL #undef THIS_FILE
iA"H*0 static char THIS_FILE[] = __FILE__;
/'>ck2drjk #endif
U}-hV@y
#define MAX_KEY 100
eoiC.$~\ #define CTRLBIT 0x04
/cD]m #define ALTBIT 0x02
w*4sT+
P #define SHIFTBIT 0x01
sR$/z9w #pragma data_seg("shareddata")
aU] nh. a HHOOK hHook =NULL;
c
8|&Q UINT nHookCount =0;
0gKSjTqo static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
~Z97L static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
R"71)ob4 static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
vrsOA@ee3H static int KeyCount =0;
pD6a+B\;k static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
'&y+,2?;Y[ #pragma data_seg()
Y;sN UX HINSTANCE hins;
,fs>+]UY3 void VerifyWindow();
\mwxV!!b$ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
!h*F58 //{{AFX_MSG_MAP(CHookApp)
wA%,_s/U // NOTE - the ClassWizard will add and remove mapping macros here.
dM5N1$1, // DO NOT EDIT what you see in these blocks of generated code!
QnH~'
k //}}AFX_MSG_MAP
I9cZZ`vs END_MESSAGE_MAP()
~0{F,R.$ vqwSOh|P9 CHookApp::CHookApp()
G4f%=Z {
`]l[p+DO // TODO: add construction code here,
{/qq*0wa // Place all significant initialization in InitInstance
9q<?xO }
pH.&OW% I}/-zyx>= CHookApp theApp;
"Ze<dB#,Y LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
[PU0!W; {
!~f!O"n)3r BOOL bProcessed=FALSE;
#_fL[j& if(HC_ACTION==nCode)
,09d"7`X
{
=Wl}Pgo! if((lParam&0xc0000000)==0xc0000000){// Key up
+dK;\wT switch(wParam)
U\tujK1 {
)u5+<OG}= case VK_MENU:
pGSS
MaskBits&=~ALTBIT;
B#x.4~YX break;
@RI\CqFHR case VK_CONTROL:
RD'i(szi? MaskBits&=~CTRLBIT;
O8w|!$Q. break;
G9a6 $K)b case VK_SHIFT:
{rZ )! MaskBits&=~SHIFTBIT;
JXF@b-c break;
Q>>II|~;J default: //judge the key and send message
l=t$XWh! break;
q{oppali }
\MFjb IL for(int index=0;index<MAX_KEY;index++){
1mz72K if(hCallWnd[index]==NULL)
By}>h6`[ continue;
BjCg!6`XF if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
<bgFc[Z {
6
VuMx7W1 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
$"x~p1P bProcessed=TRUE;
.uu[MzMIu }
XSz)$9~hk }
~i/K7qZ }
.Zv uhOn^ else if((lParam&0xc000ffff)==1){ //Key down
G^/8lIj switch(wParam)
dgM@|&9*m {
4z> SI\Ss case VK_MENU:
<;nhb MaskBits|=ALTBIT;
[&a=vE break;
YhNO{4D case VK_CONTROL:
/%w3(e MaskBits|=CTRLBIT;
GbN|!,X1m break;
YB'BAX<lI case VK_SHIFT:
xnD"LK MaskBits|=SHIFTBIT;
M[7$cfp-Y~ break;
,fW%Qv default: //judge the key and send message
C{8(ew break;
z1 P=P%F }
2io~pk> for(int index=0;index<MAX_KEY;index++)
MF/@Efjn
] {
tEHgQto if(hCallWnd[index]==NULL)
ae|j#!~oi continue;
K/ 5U;oC if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
1=Nh<FuQ {
ct![eWsuB SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
~zT7 43 bProcessed=TRUE;
R\d)kcy4 }
sW]fPa(cn, }
aJ^RY5 }
]KE"|}B if(!bProcessed){
B(h%>mT[ for(int index=0;index<MAX_KEY;index++){
TdWatvY5p if(hCallWnd[index]==NULL)
.7|Iausv continue;
%uy5la if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
24Uvi:B?~ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
$I }k>F }
.DG`~Fpk }
R /0zB }
p]erk return CallNextHookEx( hHook, nCode, wParam, lParam );
/Mmts=^Ja }
GP{$w_'!J0 !ZrU@T BOOL InitHotkey()
%UokR" {
Uon^z?0A if(hHook!=NULL){
@K=C`N_22 nHookCount++;
f )Ef-o return TRUE;
3P2x%G p }
"1HKD else
j9^V)\6) hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
_-5| "oJ if(hHook!=NULL)
,zVS}!jRhy nHookCount++;
Zb}U 4 return (hHook!=NULL);
P}8cSX9 }
$QB/n63 BOOL UnInit()
2D)B%nM[ {
L-eO_tTh0 if(nHookCount>1){
5u=>~yK+ nHookCount--;
yB2}[1 return TRUE;
( we)0AxF' }
7tQ?av BOOL unhooked = UnhookWindowsHookEx(hHook);
i#bcjH if(unhooked==TRUE){
#sM`>KG6T1 nHookCount=0;
[PX%p;"D hHook=NULL;
_Nacqa }
A"i$.dR{ return unhooked;
s
a{x.2/o} }
>["X(%&w 2$TwD*[ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
8h,=yAn5 {
.s-*aoj BOOL bAdded=FALSE;
w:aV2 for(int index=0;index<MAX_KEY;index++){
7_ s7); if(hCallWnd[index]==0){
\=uD)9V hCallWnd[index]=hWnd;
08G${@D+X0 HotKey[index]=cKey;
U(/8dCyyY HotKeyMask[index]=cMask;
V@o#" gZ bAdded=TRUE;
{5Sy=Y KeyCount++;
fUq:`#Q break;
J_ 7#UjGA, }
g&I|@$\ }
;
,n}>iTE return bAdded;
=z!/:M }
unc8WXW L<k(stx~ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
RA1K$D ?A {
nxMZd=Y BOOL bRemoved=FALSE;
BU.O[?@64 for(int index=0;index<MAX_KEY;index++){
IoZ_zz0 if(hCallWnd[index]==hWnd){
bF'Jm*f if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
DT3"uJTt hCallWnd[index]=NULL;
~,7Tj HotKey[index]=0;
?7uK:'8 HotKeyMask[index]=0;
x%W% bRemoved=TRUE;
X`28? KeyCount--;
Yk0/f|>O break;
+CN!3(r }
~9Qd83`UH }
.iYp9?t }
W.BX6 return bRemoved;
?=G{2E. }
'x6rU"e $J wOg#J void VerifyWindow()
'| p"HbJ {
L~Y^O`c for(int i=0;i<MAX_KEY;i++){
RTr"#[ if(hCallWnd
!=NULL){ I]a [Ngj
if(!IsWindow(hCallWnd)){ f7/M _sx
hCallWnd=NULL; OlP1Zd/l
HotKey=0; q$PO.#
HotKeyMask=0; _+,>NJ
KeyCount--; i0F6eqe=J
} Qs ysy
} j'`-3<k
} KW!+Ws
} gx8i|]
m-bu{
BOOL CHookApp::InitInstance() }W0_eQ
{ NMS+'GRW
AFX_MANAGE_STATE(AfxGetStaticModuleState()); YC(X=
D
hins=AfxGetInstanceHandle(); wxJoWbn
InitHotkey(); kB.CeG]tk
return CWinApp::InitInstance(); 2!R+5^Iy
} PD~vq^@Q
s|I$c;>
int CHookApp::ExitInstance() CEAmb[h
{ vNju|=Lo
VerifyWindow(); 9_O6Sl
UnInit(); |w{C!Q8l
return CWinApp::ExitInstance(); CB#B!;I8v
} 3$S~!fh
7AlL,&+
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file 6F5g2hBz
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) WIabQ_ fX
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ Tp|>(~;ai
#if _MSC_VER > 1000 Y]7 6y>|e
#pragma once bFSs{\zE
#endif // _MSC_VER > 1000 Ym.{
{^=
{eVv%sbq
class CCaptureDlg : public CDialog `O5427Im
{ v#EFklOP
// Construction [8Fn0A
public: ?aI.Z+#
BOOL bTray; M:dH>
BOOL bRegistered; !f]kTs]j~
BOOL RegisterHotkey(); &8I}q]'k
UCHAR cKey; SLRF\mh!L
UCHAR cMask; +cM~|
void DeleteIcon(); %CrTO(
void AddIcon(); BwrX.!M
UINT nCount; n5z|@I`S_
void SaveBmp(); \_YDSmjy
CCaptureDlg(CWnd* pParent = NULL); // standard constructor wbvOf X
// Dialog Data ksTK'7*
//{{AFX_DATA(CCaptureDlg) 4)8e0L*[B?
enum { IDD = IDD_CAPTURE_DIALOG }; HYL['B?Wid
CComboBox m_Key; 0Y:)$h2?
BOOL m_bControl; 2x<!>B
BOOL m_bAlt; z{&