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:
4JTFdbx
n')#]g0[ 一、实现方法
<uugT9By QY,.| 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:
JNzNK.E!m- wn'_;0fg #pragma data_seg("shareddata")
}ug|&25D HHOOK hHook =NULL; //钩子句柄
{YCquoF UINT nHookCount =0; //挂接的程序数目
hi>sDU<x static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
<}c`jN!z. static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
W9{>.E? static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
F<y5zqGy@ static int KeyCount =0;
ELp @/c=Wr static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
^/Id!Y7 #pragma data_seg()
eD0Rv0BV^ ]_S&8F}| 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。
=o5ZcC -Bqn^ E
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:
~;Ga65_6_ aDx{Q& BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
"YlN_U cKey,UCHAR cMask)
U@<>2 {
Oj#nF@U BOOL bAdded=FALSE;
Z2Bl$ \ for(int index=0;index<MAX_KEY;index++){
;as4EqiK if(hCallWnd[index]==0){
m8Q6ESg<*u hCallWnd[index]=hWnd;
Q"UQv< HotKey[index]=cKey;
c~0YIk>] HotKeyMask[index]=cMask;
:^DuB_ bAdded=TRUE;
*`:zSnu KeyCount++;
iPMI$ break;
eUYd0L! }
xf8C$|, }
zof>S>5>R7 return bAdded;
A f@IsCOJ }
1"r6qYN!> //删除热键
)MFa~/x BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
~n#rATbxf {
<_@ S@t) BOOL bRemoved=FALSE;
FAVw80?5k for(int index=0;index<MAX_KEY;index++){
Ed3 *fY if(hCallWnd[index]==hWnd){
FO{K=9O if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Be{7Rj v hCallWnd[index]=NULL;
,z1X{ HotKey[index]=0;
@|xcrEnP}B HotKeyMask[index]=0;
O2E6F^.pYw bRemoved=TRUE;
8CxC`*L( KeyCount--;
I
U/HYBJH break;
1(`>9t02/? }
A]2zK?|s }
dA[Z\ }
"E;]?s9x return bRemoved;
j_E$C.XU{g }
@x">e][B 9l?#ZuGXp vLW&/YJ6 DLL中的钩子函数如下:
DCv~^ D+/27# LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
QDS=M] {
ir<HC 'D[ BOOL bProcessed=FALSE;
A-vK0l+ if(HC_ACTION==nCode)
_f%Wk>A4 {
PNLtpixZ if((lParam&0xc0000000)==0xc0000000){// 有键松开
~/J:p5?L switch(wParam)
&[}T41 {
n83,MV?- case VK_MENU:
UBp0;)- MaskBits&=~ALTBIT;
Bry\"V"'g break;
+(VHnxNQs case VK_CONTROL:
8V%(SV MaskBits&=~CTRLBIT;
K
oPTY^ break;
+Sk ; case VK_SHIFT:
\+mc MaskBits&=~SHIFTBIT;
az~4sx$+} break;
XM$r,}B k default: //judge the key and send message
aDuO!?Cm break;
UUy|/z% }
0[g8 for(int index=0;index<MAX_KEY;index++){
zp>q$e40 if(hCallWnd[index]==NULL)
R_ojK&% continue;
b>AFhj : if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
&Ib8xwb: {
0"$Ui#r` SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
bNR}Mk]? bProcessed=TRUE;
~WK>+T,% }
4(MZ*6G]? }
,KF>PoySA }
_>B0q|]j4' else if((lParam&0xc000ffff)==1){ //有键按下
2-i>ymoOS switch(wParam)
b(dIl)Y4
: {
3!^5a%u case VK_MENU:
?fDF Rms MaskBits|=ALTBIT;
a?CV;9 break;
s8.O L_e case VK_CONTROL:
LbDhPG`u MaskBits|=CTRLBIT;
7nB@U$]-Sz break;
|D%i3@P&ZR case VK_SHIFT:
nmp(%;<exN MaskBits|=SHIFTBIT;
6|3$43J,F break;
~M%r.WFpA default: //judge the key and send message
QA\eXnR break;
2/f:VB?<T }
k2l(!0o|; for(int index=0;index<MAX_KEY;index++){
CZv.$H"lW if(hCallWnd[index]==NULL)
hHF YAh continue;
g?!vRid@S if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
SlI0p&2, {
#Yi,EwD SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
"BZ6G` bProcessed=TRUE;
RG-pN() }
w1EYXe }
\"c;MK{ }
$:w4_X5T if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
:BG/]7>|V for(int index=0;index<MAX_KEY;index++){
9VdVom|e if(hCallWnd[index]==NULL)
?c0OrvM continue;
a02;Zl if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
K~OfC SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
v:(_-8:F //lParam的意义可看MSDN中WM_KEYDOWN部分
,# rl" }
703=.xj }
|U%S<X }
O/$pT%D1x return CallNextHookEx( hHook, nCode, wParam, lParam );
.|$6Pi%! }
>l{<p( h|"98PI 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
cAIMt]_ #>dfP"}&, BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
gbM#jhQ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
'WkDpa 'n%Ac&kk 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
:)X?ML? q[1:h LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
Q^4j {
!r$?66q/ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
Ha9A5Ao}0 {
g
nJe!E //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
#~%tdmGuL SaveBmp();
4(Gs$QkSo| return FALSE;
bvzeUn }
h"cLZM:6 …… //其它处理及默认处理
S',i }
Q[`J= DesvnV'{`
aN{C86wx 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。
Dp!3uR']p ?I&ha-." 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。
|3W\^4>, $/5<f<%u&) 二、编程步骤
l;zp f|.Vc lg1yj}br 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";
#z 3tSnmp >K**SjVG 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
<n< @
O5 fRC(Yyx 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;
H[?~u+ |\"vHt?@G 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;
_;",7bT80 ~>zml1aJ6 5、 添加代码,编译运行程序。
\]=qGMwFs saQA:W; 三、程序代码
8WK%g0gm WJCEiH ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
$Z(fPKRN/ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
Fv=7~6~ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
bs$x%CR #if _MSC_VER > 1000
SHS:>V #pragma once
oB;EP #endif // _MSC_VER > 1000
eW#U<x%P #ifndef __AFXWIN_H__
awN{F6@ZE #error include 'stdafx.h' before including this file for PCH
S]iMZ \I/ #endif
3 G/#OJ #include "resource.h" // main symbols
evryk,x class CHookApp : public CWinApp
R?!xO-^t {
FLdO public:
WV_y@H_ CHookApp();
de]r9$D // Overrides
L+2!Sc,> // ClassWizard generated virtual function overrides
::Y //{{AFX_VIRTUAL(CHookApp)
:L<$O7 public:
i|+ EC_^< virtual BOOL InitInstance();
8`}(N^=} virtual int ExitInstance();
yaV=e1W //}}AFX_VIRTUAL
c'?4*O //{{AFX_MSG(CHookApp)
qG3 [5lti // NOTE - the ClassWizard will add and remove member functions here.
jXq~ x"( // DO NOT EDIT what you see in these blocks of generated code !
xevG)m //}}AFX_MSG
E;\XZ<E DECLARE_MESSAGE_MAP()
),%/T,!@ };
-]c5**O} LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
k .? aq BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
wOQ-sp0q0 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
z)"7qqA BOOL InitHotkey();
dO.?S89L BOOL UnInit();
Y,K): ~T #endif
^/\OS@CT\ px5~D(N //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
9{@ #tx #include "stdafx.h"
;m$F~!Y #include "hook.h"
=t1.j=oC
#include <windowsx.h>
d
(]t} #ifdef _DEBUG
3)v6N_ #define new DEBUG_NEW
X||Z>w}v #undef THIS_FILE
]X~;?>#:p static char THIS_FILE[] = __FILE__;
E15"AO #endif
2/S~l;x #define MAX_KEY 100
0HK03& #define CTRLBIT 0x04
0/P!rH9 #define ALTBIT 0x02
iOz<n
z #define SHIFTBIT 0x01
\ &1)k/ #pragma data_seg("shareddata")
[z#C&gDt HHOOK hHook =NULL;
F_;oZ UINT nHookCount =0;
"8|y static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
NfcY30}: static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
7><n e|% static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
CK[2duf^~ static int KeyCount =0;
)
?rJKr[` static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
Ao)hb4ex #pragma data_seg()
1 Y_e1tgmm HINSTANCE hins;
=$601r void VerifyWindow();
h+F@apUS BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
']^e,9=Q //{{AFX_MSG_MAP(CHookApp)
G|FF // NOTE - the ClassWizard will add and remove mapping macros here.
e"(l // DO NOT EDIT what you see in these blocks of generated code!
5zG6V2 //}}AFX_MSG_MAP
n's3!HQY[ END_MESSAGE_MAP()
bsVms,& Pm; /Ua CHookApp::CHookApp()
5 (bG {
,GEMc a,` // TODO: add construction code here,
Ti`<,TA54 // Place all significant initialization in InitInstance
3N6U6.Tqb }
R L/~E
xYC BX$t |t;!m CHookApp theApp;
|`T3H5X> LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
bep}|8,#u {
p#~'xq BOOL bProcessed=FALSE;
m&o}qzC'y if(HC_ACTION==nCode)
mLX1w)=r {
VpSk.WY/ e if((lParam&0xc0000000)==0xc0000000){// Key up
}CZ,WJz= switch(wParam)
UN_f2 {
<b"ynoM.A case VK_MENU:
P;0tI; MaskBits&=~ALTBIT;
1)
V,>)Ak break;
1;r^QAK& case VK_CONTROL:
Va Z+TE MaskBits&=~CTRLBIT;
s`Fv! break;
lM Gz"cym case VK_SHIFT:
B'6^E#9 MaskBits&=~SHIFTBIT;
hk4f)z break;
R-]QU`c default: //judge the key and send message
_H@s^g break;
Nk=F.fp|/ }
quk~z};R>\ for(int index=0;index<MAX_KEY;index++){
#EtS9D'd+ if(hCallWnd[index]==NULL)
Mp;t?C4 continue;
m>2b %GTh if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
lGqwB,K$z4 {
P$_Y:XI ! SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
|o~<Ti6] bProcessed=TRUE;
"T5?<c }
VHVU*6_w }
T:x5 ,vpM }
:xZ/c\ else if((lParam&0xc000ffff)==1){ //Key down
f]"][!e!, switch(wParam)
_v4TyJ {
w_G/[R3 case VK_MENU:
xtf]U:c MaskBits|=ALTBIT;
6HpSZa break;
l;U9dO}/[ case VK_CONTROL:
n"Ec %n MaskBits|=CTRLBIT;
u,[Yaw"L break;
FOpOS?Cr' case VK_SHIFT:
!Jb?rSJ.h MaskBits|=SHIFTBIT;
g.f!Uc{ break;
YD2M<.U default: //judge the key and send message
>#dNXH]9 break;
|DfYH~@( }
=%Gecj for(int index=0;index<MAX_KEY;index++)
Cca(
oV {
1JgnuBX" if(hCallWnd[index]==NULL)
/MTS>[E continue;
^te9f%>$l if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
xXH%7%W'f {
qfE/,L(B SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
%^^2 bProcessed=TRUE;
ZA>hN3fE' }
ttLChL }
R+lKQAyC0= }
hU5[k/ q if(!bProcessed){
V'pNo&O= for(int index=0;index<MAX_KEY;index++){
iKV;>gF,)v if(hCallWnd[index]==NULL)
E5 H6&XU continue;
jD0^,aiG if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
U/,`xA;v> SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
h+zJ"\ }
s`Z(f:/6* }
t-dN:1 }
JXBW0|8b return CallNextHookEx( hHook, nCode, wParam, lParam );
/7|u2!#Ui }
7~cN )=9\6zXS BOOL InitHotkey()
IkH]W!_+ {
kJy<vb~
if(hHook!=NULL){
/YHBhoat nHookCount++;
4 *He<2g return TRUE;
Wf13Ab }
1W8[
RET else
zF<*h~ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
v[CX-CBZ? if(hHook!=NULL)
xZtA) Bp nHookCount++;
6VolTy@(x return (hHook!=NULL);
0@,,YZf }
X"J79?5 BOOL UnInit()
HoymGU`w {
w |>:mQnU if(nHookCount>1){
?A(=%c|,g nHookCount--;
)HS|pS: return TRUE;
W2tIt&{ }
`>rdn*B BOOL unhooked = UnhookWindowsHookEx(hHook);
9+@_ZI- if(unhooked==TRUE){
u%5B_<90V nHookCount=0;
=NAL*4c+ hHook=NULL;
O-wR48Q }
k<"ZNQm$. return unhooked;
HYLU]9aH8 }
?ZdHuuDN~ f!P.=Qo[= BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
"My \&0- {
,V)yOLApVj BOOL bAdded=FALSE;
vkE6e6,Qc for(int index=0;index<MAX_KEY;index++){
"<3PyW?zt if(hCallWnd[index]==0){
^O#,%>1J hCallWnd[index]=hWnd;
y2\, L HotKey[index]=cKey;
P~;NwHZ?k HotKeyMask[index]=cMask;
gO<>L0,j bAdded=TRUE;
6aCAz2/ KeyCount++;
P_hwa1~d break;
|GL#E"[&' }
{\`#,[ }
X)fj& return bAdded;
o?$D09j;; }
?.|qRzWL iK(n'X5i BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Mh>^~; {
r&0v,WSp&S BOOL bRemoved=FALSE;
azPFKg+ for(int index=0;index<MAX_KEY;index++){
eXnMS!g%Z if(hCallWnd[index]==hWnd){
7 -gt V# if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
-[`,MZf hCallWnd[index]=NULL;
=B*,S#r HotKey[index]=0;
J.?6a:#bU/ HotKeyMask[index]=0;
nEQw6q~je bRemoved=TRUE;
:uZcN KeyCount--;
HkJ$r<J2 break;
zjM+F{P8 }
O9p8x2 }
s~]Ri:7~ }
wjoxfPnf return bRemoved;
m]=|%a6 }
vhTte
|( 6T"[M void VerifyWindow()
cQu1WgQ
G {
a[xEN7L~4D for(int i=0;i<MAX_KEY;i++){
YX18!OhQ if(hCallWnd
!=NULL){ v)d\
5#7
if(!IsWindow(hCallWnd)){ /0!6;PC<
hCallWnd=NULL; 50l=B]M
HotKey=0; ~k+-))pf
HotKeyMask=0; [#)-F_S
KeyCount--; |6"zIHvtc
} 6jRF[N8
} xO'1|b^&
} /=lrdp!a
} 3Q~ng2Wv%
puL1A?Y8UM
BOOL CHookApp::InitInstance() |0B h
{ 0kQAT#
AFX_MANAGE_STATE(AfxGetStaticModuleState()); N02N
w(pi
hins=AfxGetInstanceHandle(); Q6RBZucv
InitHotkey(); kE UfQLbn
return CWinApp::InitInstance(); Goz9"yazg
} ;?yd;GOt)
JdfjOlEb
int CHookApp::ExitInstance() 87>\wUJ
{ K
S,X$)9
VerifyWindow(); G7M:LcX
UnInit(); Hl?\P6
return CWinApp::ExitInstance(); _E:]qv
} . AWRe1?
'S)}mG_
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file r_-iOxt~5
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_)
xdXt
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ ,l#V eC
#if _MSC_VER > 1000 /"~CWNa
#pragma once i=o<\{iV:
#endif // _MSC_VER > 1000 +[V?3Gdb
xQm!
class CCaptureDlg : public CDialog Tr(w~et
{ 3E+u)f lmB
// Construction :p=IZY
public: PE]jYyyHtU
BOOL bTray; <S6|$7{1
BOOL bRegistered; (YGJw?]
BOOL RegisterHotkey(); |TkMrj0
UCHAR cKey; S)n~^q
UCHAR cMask; My5h;N@C
void DeleteIcon(); x!tCK47Yq
void AddIcon(); [wjA8d.
UINT nCount; L@ql)Lc);
void SaveBmp(); s0E:hn:
CCaptureDlg(CWnd* pParent = NULL); // standard constructor &xj?MgdNL
// Dialog Data ZxwI< T:&
//{{AFX_DATA(CCaptureDlg) +'N?`l6<
enum { IDD = IDD_CAPTURE_DIALOG }; Z8 1]>
CComboBox m_Key; 4@4$kro
BOOL m_bControl; :jT1=PfL
BOOL m_bAlt; U9y[b82
BOOL m_bShift; L
V?- g
CString m_Path; DdN{=}A
CString m_Number; 0%cbno@1V
//}}AFX_DATA <I&X[Sqp
// ClassWizard generated virtual function overrides ?Sh]m/WZd[
//{{AFX_VIRTUAL(CCaptureDlg) =xw) [
public: 54-sb~]
virtual BOOL PreTranslateMessage(MSG* pMsg); E-MEMran4
protected: p4fU/
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support K!).QB'
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); H .JA)*b-
//}}AFX_VIRTUAL ,&G