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:
T>?~eYHXs
?#'qY6 ^ 一、实现方法
$W2AiE[Wm +J} 41 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
E9i WGSE x9=lN^/4 #pragma data_seg("shareddata")
-:QyWw/d HHOOK hHook =NULL; //钩子句柄
`#V"@Go UINT nHookCount =0; //挂接的程序数目
*VUXw@ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
U7W ct % static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
6!$S1z#wM static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
bu.36\78 static int KeyCount =0;
;"3Mm$ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
4 R]| #pragma data_seg()
>h9U~#G= |Yx8Ez 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。
g 0L 4 UpITx]y?"m 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:
[|YMnV<B ">o/\sXeH BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
:X#(T-!t cKey,UCHAR cMask)
ch&r. {
4Y]`> ;w BOOL bAdded=FALSE;
=P!Vi6[gF~ for(int index=0;index<MAX_KEY;index++){
-}(W=r\ if(hCallWnd[index]==0){
C9z{8 ; hCallWnd[index]=hWnd;
Um~jp:6p HotKey[index]=cKey;
}MX`WW0\]Z HotKeyMask[index]=cMask;
~?p
> L bAdded=TRUE;
ms$o,[ KeyCount++;
%wO~\:F8 break;
X}ZOjX! }
1li`+~L
F }
(#:Si~3 return bAdded;
>iCMjT]4 }
_I9TG.AA. //删除热键
GHkSU;}) BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
p#&6Ed*V {
'D4NPG`z BOOL bRemoved=FALSE;
^~0r+w61 for(int index=0;index<MAX_KEY;index++){
.cb mCFXL if(hCallWnd[index]==hWnd){
Zj JD@,j if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
%F7aFvl* hCallWnd[index]=NULL;
^ey\ c1K HotKey[index]=0;
WM#!X!Vo HotKeyMask[index]=0;
AIeYy-f bRemoved=TRUE;
0C7"*H0R KeyCount--;
bhI8b/ break;
S$#Awen"@ }
n5b
N/ }
H\S,^)drJ? }
29GiNy+ob return bRemoved;
m4iR
'~L} }
BK +JHT h3:,Gbyap ~7m+cWC-+ DLL中的钩子函数如下:
CR/LV]G $qvNv[ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Eg9502Bl~8 {
4 (yHD BOOL bProcessed=FALSE;
ql8:s>1T if(HC_ACTION==nCode)
s(dox; d {
k91Y"_& if((lParam&0xc0000000)==0xc0000000){// 有键松开
41.+3VP switch(wParam)
RsbrD8*AD {
vw3W:TL case VK_MENU:
2|cIu ' U MaskBits&=~ALTBIT;
>[p+L=' break;
*-n$n case VK_CONTROL:
[`&cA#C9Yp MaskBits&=~CTRLBIT;
>A)he!I break;
ua{eri[ case VK_SHIFT:
Ze~\=X" " MaskBits&=~SHIFTBIT;
;HC"hEc! break;
Pk,^q8; default: //judge the key and send message
U!Lws#\X break;
j04Q3d
\f }
e#AB0-f for(int index=0;index<MAX_KEY;index++){
qj|GAGrQ2 if(hCallWnd[index]==NULL)
q\~7z1 continue;
D Lu]d$G if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
b"gYNGgX {
+vQyHo SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
<
;g0?M\ bProcessed=TRUE;
JmBYD[h, }
kN_LD- }
h$k(|/+ }
T7,tJk,( else if((lParam&0xc000ffff)==1){ //有键按下
j_{gk"2:d` switch(wParam)
5pDxFs=v {
4uv }6&R case VK_MENU:
&O'yhAP] j MaskBits|=ALTBIT;
iCHZ{<k break;
#*~ ( case VK_CONTROL:
.1}u0IbJ MaskBits|=CTRLBIT;
sC#Ixq'ls7 break;
(d ( whlF case VK_SHIFT:
M,9WF)p)V MaskBits|=SHIFTBIT;
0t9G$23 break;
Fm@GU default: //judge the key and send message
LR^b?.#> break;
IuTTMAt }
LvR=uD for(int index=0;index<MAX_KEY;index++){
[-%oO if(hCallWnd[index]==NULL)
w#o<qrpHf continue;
0
cQf_o if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
:9)>!+|' {
l+#` SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
$Fo ,$ bProcessed=TRUE;
iX,Qh2(ig }
vEb~QX0~ }
*Vc}W }
j/W#=\xz if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
f(3#5288 for(int index=0;index<MAX_KEY;index++){
&38Fj'l if(hCallWnd[index]==NULL)
lmod8B continue;
3:C *'@ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
MXhS\vF#m SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
9|go`^*. //lParam的意义可看MSDN中WM_KEYDOWN部分
/E*P0y~KTW }
)~Q$ tM` }
TKmC/c }
UqAvFCy return CallNextHookEx( hHook, nCode, wParam, lParam );
w0.#/6 }
0D\FFfs f[z#=zv 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:
3U}z?gP[ CfVz' BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
{d3r>Ub)7d BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
=\q3;5[ rsIjpPa 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:
1mB6rp U$-FQRM4K LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
lKm?Xu'yH {
osnDW
aN if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
0w c+<CUW {
t%/5$<!b //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
:]]amziP& SaveBmp();
$k!t&G return FALSE;
Zw }7vD0 }
ld3,)ZY …… //其它处理及默认处理
oc15!M3$ }
D3jP hPy. UH)A n:9 Z(V4"x7F 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。
pIh@!C } wiq?dr 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。
BKGwi2]Ry ){6;o&CC: 二、编程步骤
T$+}Srb Z,!Rj7wZ 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
7`P(LQAr! &)wQ|{P~k 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
j6Vuj/+} ?.4u'Dkn= 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
9zX\ioT F[J;u/Z 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
7%o\O{,U -
@ 5、 添加代码,编译运行程序。
=EIsqk^* (5atU |8r 三、程序代码
NE/3aU k1]?d7g$w ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
r*kk/$,2 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
/at#[Pw~01 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
H
>RGX#| #if _MSC_VER > 1000
JNZKzyJ9K #pragma once
R^K<u#>K #endif // _MSC_VER > 1000
aZmSCi:&' #ifndef __AFXWIN_H__
2Qn%p[#n #error include 'stdafx.h' before including this file for PCH
`B^?Za,xN #endif
VD1*br^, #include "resource.h" // main symbols
KC class CHookApp : public CWinApp
^^v\ T {
"F0,S~tZZ public:
hLBX,r)u CHookApp();
}|x]8zL8G // Overrides
6 Iup4sP // ClassWizard generated virtual function overrides
d,$[633It} //{{AFX_VIRTUAL(CHookApp)
Vls*fY:W public:
Um*{~=;u virtual BOOL InitInstance();
M34*$>bk virtual int ExitInstance();
Z EG //}}AFX_VIRTUAL
u<):gI //{{AFX_MSG(CHookApp)
k8w8I$QEM // NOTE - the ClassWizard will add and remove member functions here.
Iy"
// DO NOT EDIT what you see in these blocks of generated code !
y\ouIsI77 //}}AFX_MSG
96 C|R DECLARE_MESSAGE_MAP()
n#m )]YQC };
b`1P%OjC LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
h v9s BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
E4WoKuE1$ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
4Jht{#IIG BOOL InitHotkey();
A/GEDG
? BOOL UnInit();
]x~H"<V #endif
QHA<7Wg xH*OEzN //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Ff.gRx #include "stdafx.h"
c~p4M64 #include "hook.h"
R$v{ p[ #include <windowsx.h>
[<bfwTFsl #ifdef _DEBUG
8sE@?, #define new DEBUG_NEW
uGgR@+7?Z #undef THIS_FILE
4,FuQ} static char THIS_FILE[] = __FILE__;
}>SHTHVye #endif
WtdWD_\%Y\ #define MAX_KEY 100
;c~6^s`2 #define CTRLBIT 0x04
\Q]2Zq #define ALTBIT 0x02
tTC[^Dji #define SHIFTBIT 0x01
TVYO`9:CW #pragma data_seg("shareddata")
?. CA9!| HHOOK hHook =NULL;
+|\dVe. UINT nHookCount =0;
1)M3*h3 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
L{osh0 static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
670g|&v. static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
Pgb<;c:4 static int KeyCount =0;
1P&c:n static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
O'o` #pragma data_seg()
QIGMP=!j HINSTANCE hins;
z]~B@9l void VerifyWindow();
]yA|
m3^2 BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
(l9U7^S"{K //{{AFX_MSG_MAP(CHookApp)
!*N#}6Jd // NOTE - the ClassWizard will add and remove mapping macros here.
L;>tuJY1 // DO NOT EDIT what you see in these blocks of generated code!
oE)tK1>;H //}}AFX_MSG_MAP
~M+|g4W% END_MESSAGE_MAP()
]w! x CShVJ:u+K\ CHookApp::CHookApp()
R)ejIKtY {
hE+6z%A8 // TODO: add construction code here,
%I[(`nb // Place all significant initialization in InitInstance
.-fJ\`^mi }
hyFq>XFo TRG"fVR CHookApp theApp;
;,4 Z5+ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Rm"lRkY4I[ {
'V .4Nhd BOOL bProcessed=FALSE;
Spt[b.4m F if(HC_ACTION==nCode)
EzwYqw {
_qM'm^z5 if((lParam&0xc0000000)==0xc0000000){// Key up
N%n#mV; switch(wParam)
*p p1U>, {
eQJLyeR+ case VK_MENU:
&A]*"lt|w MaskBits&=~ALTBIT;
J3g>#N]='( break;
V_(lZDjh* case VK_CONTROL:
-N~*h MaskBits&=~CTRLBIT;
PUF"^9v break;
hP,SvN#!2 case VK_SHIFT:
[Kx_ %Le
MaskBits&=~SHIFTBIT;
0}-&v+ break;
lD.PNwM default: //judge the key and send message
Ond"Eq=r break;
R2Lq,(@- }
/w`{]Ntgu for(int index=0;index<MAX_KEY;index++){
3Ud&B if(hCallWnd[index]==NULL)
rN8 ZQiJC continue;
p~$\@8@ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
o~ 2bk<]z {
a| SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
)
^!oM bProcessed=TRUE;
&}wKC:LSP }
V! a|rTU6 }
`%"zq"1`0 }
C.FGi`rrm else if((lParam&0xc000ffff)==1){ //Key down
)d_)CuUBe switch(wParam)
&>p2N {
+);o{wfW case VK_MENU:
(SU*fD!t MaskBits|=ALTBIT;
YNH>^cD1 break;
t-3wjS1v case VK_CONTROL:
?9
m3y0 MaskBits|=CTRLBIT;
_T<ney}Y< break;
C5*j0} case VK_SHIFT:
kT []^Jtc MaskBits|=SHIFTBIT;
&7XB$ break;
0+m"eGwTm default: //judge the key and send message
(<=qW_iW break;
lD _
u }
gU0}.b for(int index=0;index<MAX_KEY;index++)
p%G4Js. {
LdDkd(k if(hCallWnd[index]==NULL)
DbH{;
Fb continue;
I7hPE7V+1 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
j+88J {
ig7)VKr SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
3-FS} {, bProcessed=TRUE;
,iB)8Km@U }
BAx)R6kS; }
JOx75} }
^Qs-@]E- if(!bProcessed){
{uDL"~^\ for(int index=0;index<MAX_KEY;index++){
ak;fCx& if(hCallWnd[index]==NULL)
hJrxb<9@Y0 continue;
P5%DvZB$w if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
AuX& SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
tQF7{F-} }
NGd|7S[^+c }
P>0j]?RB }
-!I.:97 N return CallNextHookEx( hHook, nCode, wParam, lParam );
GKZn|<Y|{c }
axxdW)+K @$F(({? BOOL InitHotkey()
acRPKTs
H {
jgs kK if(hHook!=NULL){
]j}zN2[A nHookCount++;
iePpJ>( return TRUE;
eWhv X9
< }
{Ejv8UdA9 else
Z8}Zhe. hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
ACU0 if(hHook!=NULL)
`Btdp:j8i nHookCount++;
e-]k{_wm return (hHook!=NULL);
(b GiBsb }
.1t$(]CyC BOOL UnInit()
KQNSYI7a {
$xvEYK if(nHookCount>1){
? Ls]k nHookCount--;
Km'd=B>Jy return TRUE;
VjMd&>G }
fFqK.^Tn BOOL unhooked = UnhookWindowsHookEx(hHook);
.]k(7F!W if(unhooked==TRUE){
%Jq(,u nHookCount=0;
Ad+-/hxc hHook=NULL;
a'
.o }
5lxC**NA return unhooked;
<(>v|5K0] }
Iu[^" 6aX m9J BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
/ d0LD {
KVSy^-." BOOL bAdded=FALSE;
Rl=NVo for(int index=0;index<MAX_KEY;index++){
a^)7&|$ E if(hCallWnd[index]==0){
1Yz1/gFj hCallWnd[index]=hWnd;
_U.8\J2 HotKey[index]=cKey;
YM1tP'4j@ HotKeyMask[index]=cMask;
9 /t}S6b{ bAdded=TRUE;
66[yL(*+ KeyCount++;
H
\.EKZ break;
)
ok_"wB }
tJ&S&[} }
+7sdQCO(Co return bAdded;
&julw;E }
~5:]Oux %[B &JhT BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
u8~.6]Ae {
?$ Uk[ BOOL bRemoved=FALSE;
)m\%L`+ for(int index=0;index<MAX_KEY;index++){
+4GuA0N6 if(hCallWnd[index]==hWnd){
DL2e9 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ceH7Rq:4W hCallWnd[index]=NULL;
R
7xV{o HotKey[index]=0;
f]J?-ks HotKeyMask[index]=0;
c)rI[P7Q bRemoved=TRUE;
deda=%w0 KeyCount--;
{1#5\t>9yD break;
Nr|.]=K)5n }
-XPGl }
o5BOe1_Pw }
~.VWrHC return bRemoved;
&.K8cphj }
jO3Q@N0_ j8hb void VerifyWindow()
ZT"?W $ {
dU:s^^f&R for(int i=0;i<MAX_KEY;i++){
TJ?}5h5 if(hCallWnd
!=NULL){ 2^[fUzL?
if(!IsWindow(hCallWnd)){ 1[} =,uaM
hCallWnd=NULL; nO\|43W
HotKey=0; O>n L;I
HotKeyMask=0;
nUs)
KeyCount--; QI0ARdS
} z]gxkol\
} R+]Fh4t
} fR_)e:
} 0 m";=:(w
`w[0q?}"`
BOOL CHookApp::InitInstance() b?B"u^b!
{ vTh-I&}:
AFX_MANAGE_STATE(AfxGetStaticModuleState()); d,8V-Dk+p
hins=AfxGetInstanceHandle(); TG{=~2
InitHotkey(); Tk|0
scjE^
return CWinApp::InitInstance(); MR#jI
} D7sw;{ns
I@pnZ-5
int CHookApp::ExitInstance() c?V,a`6
{ Hu1w/PLq
VerifyWindow(); A;SRm<,
UnInit(); j MW|B
return CWinApp::ExitInstance(); 87YT;Z;U&
} &EE6<-B-
8ENAif
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file XxB*lX
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) xDRK^nmC
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ >J.a,!
#if _MSC_VER > 1000 wW6?.}2zU
#pragma once vkc(-n
#endif // _MSC_VER > 1000 HR['y9U
" &p\pR~
class CCaptureDlg : public CDialog &7E 0H{
{ MCz+l0
// Construction 8%arA"#S
public: \8ulX>]
BOOL bTray; yw#P<8{/[
BOOL bRegistered; "y_$!KY%
BOOL RegisterHotkey(); h*_r='
E
UCHAR cKey; o'>jO.|
UCHAR cMask; 68;,hS*|6
void DeleteIcon(); x03G Jy5
void AddIcon(); ]A<\d
UINT nCount; 14s+&
void SaveBmp(); 0EPF;
Xx
CCaptureDlg(CWnd* pParent = NULL); // standard constructor \n`UkxZn+
// Dialog Data SY>N-fW\H:
//{{AFX_DATA(CCaptureDlg) %do|>7MO@
enum { IDD = IDD_CAPTURE_DIALOG }; YjvqU /[3
CComboBox m_Key; Vxo3RwmR
BOOL m_bControl; */O6cF7
BOOL m_bAlt; 7QQ3IepP
BOOL m_bShift; {7Dc(gNS
CString m_Path; iT
4H@
CString m_Number; ndF
Kw
//}}AFX_DATA I BES$[
// ClassWizard generated virtual function overrides ZZ[5Z=te?
//{{AFX_VIRTUAL(CCaptureDlg) <%qbU-
public: 9#O"^.Z !
virtual BOOL PreTranslateMessage(MSG* pMsg); "%,zB_ng\<
protected: ^R>&^"oI
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support e] **Z,Z
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); c6BaC@2
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HICON m_hIcon; `.L8<