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:
!RI _Uph
7Z< ~{eD, 一、实现方法
,dIev< xqG<R5k>> 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:
bE _8NA"2 qiNVaV\wr| #pragma data_seg("shareddata")
g_Z
tDxz HHOOK hHook =NULL; //钩子句柄
L.HeBeO UINT nHookCount =0; //挂接的程序数目
puC91 static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
;,&cWz static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
3v8LzS3@ static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
vgwpuRL5b static int KeyCount =0;
n3a.)tcC static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
_%nz-I #pragma data_seg()
RuPnWx! .Kb3VNgwvm 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。
%2}fW\%' X;I9\Cp]! 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:
.{V"Gn9! yix[zfQt0 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
6zi>Q?] 1 cKey,UCHAR cMask)
<CyU9`ye {
]q]xU, BOOL bAdded=FALSE;
n=.P46| for(int index=0;index<MAX_KEY;index++){
G !q[NRu if(hCallWnd[index]==0){
G*CPj^O hCallWnd[index]=hWnd;
W7S~~ HotKey[index]=cKey;
FnO@\{M"A HotKeyMask[index]=cMask;
UkL1h7}a\ bAdded=TRUE;
YZol4q|ic KeyCount++;
Q\$3l'W break;
<`}P }
Pxlc RF }
;k <dp7^ return bAdded;
80=0S^gEZ }
j6m;03<| //删除热键
K zWo}tT BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
'R7 \ {
V@
>(xe7 BOOL bRemoved=FALSE;
Cr.YSWg)4 for(int index=0;index<MAX_KEY;index++){
0,%{r.\S if(hCallWnd[index]==hWnd){
KF.{r if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
4{P+p!4 hCallWnd[index]=NULL;
"_{NdV|a HotKey[index]=0;
/I%z7f91O HotKeyMask[index]=0;
5'zXCHt bRemoved=TRUE;
EW
`hL~{ KeyCount--;
6Tl6A>%s break;
GKBoSSnV& }
A8)4nOXM }
XiW1X6 }
<tr]bCu} return bRemoved;
;l$$!PJ }
GK@OdurAR 6r)P&J !}&|a~U@`k DLL中的钩子函数如下:
`'YX>u / idI w7hi4 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
a1Fx|#!
mq {
$V~@w.-Z# BOOL bProcessed=FALSE;
Lljn\5!r< if(HC_ACTION==nCode)
B~]Kqp7yU {
Gl~l if((lParam&0xc0000000)==0xc0000000){// 有键松开
s)^/3a switch(wParam)
={BD*=i {
j q+(2 case VK_MENU:
#HUn~r MaskBits&=~ALTBIT;
p+d-7'?I break;
x?h/e; case VK_CONTROL:
9K+>;` MaskBits&=~CTRLBIT;
2\xw2VQ@P break;
~7]V^tG case VK_SHIFT:
*8}b&4O~ MaskBits&=~SHIFTBIT;
t-\+t<; break;
Q0U~s\< default: //judge the key and send message
wI%M3XaBws break;
B8@mL-Z-; }
i^s Vy for(int index=0;index<MAX_KEY;index++){
S6~y!J6Ok4 if(hCallWnd[index]==NULL)
nS+Rbhs continue;
<:S qMf if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
":!$Jnj, {
3lP;=*m. SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
]M?i:A$B bProcessed=TRUE;
yM_/_V|G }
A}9Z%U }
.t8)`MU6. }
>xFvfuyC else if((lParam&0xc000ffff)==1){ //有键按下
1NZ"\9=U switch(wParam)
LF dvz0 {
L:i&OCU2k case VK_MENU:
>*-%:ub MaskBits|=ALTBIT;
GP}; ~ break;
c./\sN@ case VK_CONTROL:
VvhfD2*T MaskBits|=CTRLBIT;
1Bh"'9-!JT break;
ho\1[xS case VK_SHIFT:
fM=o?w6v MaskBits|=SHIFTBIT;
MxE]EJZ break;
`|t,Uc|7! default: //judge the key and send message
k&Pt\- 9on break;
&YhAB\Rw }
}k^uup*{ for(int index=0;index<MAX_KEY;index++){
p Cz6[*kC if(hCallWnd[index]==NULL)
]J7qsMw continue;
=KE7NXu]- if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
SuE~Wb5& {
"zEl2Xn28_ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
4Gu'WbJ bProcessed=TRUE;
G%W9?4_K }
RY-iFydPc }
R5HT
EB }
WtM%(8Y[] if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
-cgO]q+Oq for(int index=0;index<MAX_KEY;index++){
h<.5:a if(hCallWnd[index]==NULL)
(J:+'u continue;
]!hjKu" if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
]S2rqKB SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
)2f#@0SVL //lParam的意义可看MSDN中WM_KEYDOWN部分
SB62(#YR }
_"8n&=+ }
'E|%l!xO }
E|O&bUMh return CallNextHookEx( hHook, nCode, wParam, lParam );
At7!Pas#@g }
omG2p &Vlno* 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
eg[EFI.h t@%w:*& BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
^~4]"J};M BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
N?\X2J1 (Y1*Bs[l 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
<A3%182 ni;_Un~ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
K~(RV4oF8B {
DUOoTlp if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
@|gG3 {
15:9JVH3D //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
66=[6U9 * SaveBmp();
%4~"$kE return FALSE;
Jqoo&T") }
4^7 v@3
…… //其它处理及默认处理
)nm+_U }
4n,&,R r# K?.~}82c &PMQ]B 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。
[gW eD a&s34Pd 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。
Fis!MMh.$ n
Kkpp- 二、编程步骤
dSDZMB sd u8f\)m 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\ O/^W0 >S5J^c 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
pW]j.JM h+km? j 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;
}k-V( axQ>~vWN/ 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;
'6N)sqTR bT:u|/I 5、 添加代码,编译运行程序。
>8Oa(9 n S_lGrk\j 三、程序代码
Fa("Gok[ :6Ri% Nb ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
/|EdpHx0 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
4D65VgVDM #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
1*O|[W #if _MSC_VER > 1000
Tm%5:/<8 #pragma once
-` ]9o3E7H #endif // _MSC_VER > 1000
M9"Bx/ #ifndef __AFXWIN_H__
U9
iI2$ #error include 'stdafx.h' before including this file for PCH
E ,i^rA m #endif
J*@ pM #include "resource.h" // main symbols
J""Cgf class CHookApp : public CWinApp
lm`*x=x {
'54\!yQ<{ public:
@IG's- CHookApp();
7L~*%j // Overrides
(\:Rnl // ClassWizard generated virtual function overrides
M=,pn+}y> //{{AFX_VIRTUAL(CHookApp)
:Xw|v2z%3 public:
b9H(w%7ucU virtual BOOL InitInstance();
rWht},-|1 virtual int ExitInstance();
<H-Nft>O //}}AFX_VIRTUAL
kpgvAKyx //{{AFX_MSG(CHookApp)
_S9)<RVI+ // NOTE - the ClassWizard will add and remove member functions here.
3lF"nv // DO NOT EDIT what you see in these blocks of generated code !
(cj9xROx //}}AFX_MSG
L;V8c DECLARE_MESSAGE_MAP()
I%d=c0>% };
-y.cy'$f LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
>LBA0ynh
{ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
e-dkvPr BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
a_N7X BOOL InitHotkey();
Us`=^\ BOOL UnInit();
(?zg.y #endif
u^MKqI p]aEC+q //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
J3yK^@&& #include "stdafx.h"
e#[Klh$]EW #include "hook.h"
s^u Y #include <windowsx.h>
"7cty\ #ifdef _DEBUG
B.N#9u-vW #define new DEBUG_NEW
` o)KG, #undef THIS_FILE
7xnj\9$m static char THIS_FILE[] = __FILE__;
ZTR9e\F #endif
N
R
c4*zQJ #define MAX_KEY 100
_=g&^_ #t #define CTRLBIT 0x04
9evr!=": #define ALTBIT 0x02
n>ryS/1 #define SHIFTBIT 0x01
'/O:@P5qY #pragma data_seg("shareddata")
MCN>3/81 HHOOK hHook =NULL;
xs= ~N UINT nHookCount =0;
,z&S;f.f static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
VR(R. static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
~& -h5=3 static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
5RPG3ppS static int KeyCount =0;
B&cIx~+ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
3 =enk0$ #pragma data_seg()
;!<}oZp{ HINSTANCE hins;
OnTe_JML void VerifyWindow();
5dj" UxH BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
]\*^G@HA2 //{{AFX_MSG_MAP(CHookApp)
3d}v?q78 // NOTE - the ClassWizard will add and remove mapping macros here.
NQ{(G8x9 // DO NOT EDIT what you see in these blocks of generated code!
)oIh?-WL //}}AFX_MSG_MAP
v3r3$(Hr END_MESSAGE_MAP()
?V6,>e_+ #E]K*mE' CHookApp::CHookApp()
#/>TuJc {
um,f!ho-U // TODO: add construction code here,
j_JY[sex // Place all significant initialization in InitInstance
Tpl]\L1v- }
ggDT5hb bRvGetX CHookApp theApp;
@&\Y:aRO%i LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
K<P d.: {
QFP9"FM5F BOOL bProcessed=FALSE;
H )ej]DXy if(HC_ACTION==nCode)
ACyK#5E {
Mj@2=c if((lParam&0xc0000000)==0xc0000000){// Key up
7
$y;-[E[ switch(wParam)
4en3yA0.w {
Gxw1P@<F: case VK_MENU:
=RB
{.% MaskBits&=~ALTBIT;
n&[CTOV break;
vPDw22L;' case VK_CONTROL:
Fi``l)Tt MaskBits&=~CTRLBIT;
xF8r+{_J) break;
&M13F>! case VK_SHIFT:
SwOW%o MaskBits&=~SHIFTBIT;
:[CV_ME.; break;
}$_@yt<{W@ default: //judge the key and send message
8?Zhh. break;
]PS`"o,pF$ }
$INB_/RE for(int index=0;index<MAX_KEY;index++){
9nR\7!_ if(hCallWnd[index]==NULL)
.!3e$mhV continue;
zsp%Cz7T if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
%7ngAIg {
hTDK[4e SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Qu|CXUk bProcessed=TRUE;
=F+v+zP7P }
~HmH#"VP }
}zGx0Q }
|.k'?! else if((lParam&0xc000ffff)==1){ //Key down
D?n6h\h\$% switch(wParam)
<K0epED {
?c#s}IH case VK_MENU:
-Q20af- MaskBits|=ALTBIT;
1'&.6{)P break;
Z|t=t"6" case VK_CONTROL:
s+:|b~ MaskBits|=CTRLBIT;
n\+c3 break;
}a;xs};X; case VK_SHIFT:
R1zt6oY MaskBits|=SHIFTBIT;
#Y=^4 U` break;
gH//@`6 default: //judge the key and send message
T]tP!a;K break;
+p%3pnj:K }
{;{U@Z for(int index=0;index<MAX_KEY;index++)
rI>x'0Go* {
pwFdfp if(hCallWnd[index]==NULL)
N`W[Q>n continue;
kyHli~Nr" if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
` @ QZK0Ox {
e?W
,D0h SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
M`Q$-#E: bProcessed=TRUE;
<Z^by;d|z }
|0[Buh[_:c }
D
/QLp3+o }
<D a-rv8 if(!bProcessed){
^.A*mMQ for(int index=0;index<MAX_KEY;index++){
I
Cc{ 2l if(hCallWnd[index]==NULL)
WZ-~F/:c% continue;
NsB]f{7>8+ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
19$A!kH\ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
FOF@@C~aH }
Kn^+kHh: }
C~2!@<y }
p]kEH\
sh return CallNextHookEx( hHook, nCode, wParam, lParam );
@_do<'a }
{b!{~q YdhV
a!Y BOOL InitHotkey()
"W(D0oy {
g}W`LIasv if(hHook!=NULL){
E+\?ptw nHookCount++;
H_?rbz} o return TRUE;
z"4 q%DC }
5Cdn
j else
]o'o
v hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
'J?{/O ^ if(hHook!=NULL)
k-ZO/yPo nHookCount++;
,-6Oma
- return (hHook!=NULL);
BdD]HXB|_ }
%r|sb=(yT BOOL UnInit()
YYT;a$GTo {
PaKa bPY if(nHookCount>1){
i%o%bib# nHookCount--;
rn-bfzoDS return TRUE;
Z:{|
?4 }
p4P=T@: BOOL unhooked = UnhookWindowsHookEx(hHook);
X,49(-~\ if(unhooked==TRUE){
7n5gXiI" nHookCount=0;
9G[
DuYJI hHook=NULL;
h~#iGs }
&@6xu{o return unhooked;
Ll
KO(Q{" }
<N)!s&D vm! y2 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
JRB6T _U {
M@T{uo BOOL bAdded=FALSE;
v-#,@&Uwq for(int index=0;index<MAX_KEY;index++){
)+L|<6J XA if(hCallWnd[index]==0){
Gsh9D hCallWnd[index]=hWnd;
obvE m[x!Z HotKey[index]=cKey;
+<Gp >c HotKeyMask[index]=cMask;
MnD}i&k[ bAdded=TRUE;
<{W{
Y\_A> KeyCount++;
$z_yx
`5 break;
:aOR@])>o }
^=x /:0 }
|Z>-<]p9g return bAdded;
i"V.$|, }
)5@P|{FF ykC3Z<pI. BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
E+Bc>xl@m {
~R;/u")@e BOOL bRemoved=FALSE;
)1
-<v); for(int index=0;index<MAX_KEY;index++){
XHA|v^ if(hCallWnd[index]==hWnd){
r:sa|+ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
HVa D hCallWnd[index]=NULL;
@K <Onh` HotKey[index]=0;
/Qst :q HotKeyMask[index]=0;
xuUEJ
a& bRemoved=TRUE;
pEwo}NS*H KeyCount--;
Bv7FZK3 break;
bo#xqSGQ }
ir6aV|ea! }
?q`i
MiN }
G/JGb2I/7| return bRemoved;
uBts?02 }
bkdXBCBx? 5ih>x3S1/ void VerifyWindow()
+[
?!@) {
6c!F%xU} for(int i=0;i<MAX_KEY;i++){
#H7
SLQr\ if(hCallWnd
!=NULL){ JLm3qIC
if(!IsWindow(hCallWnd)){ Dspvc
hCallWnd=NULL; Pyuul4(
HotKey=0; )<HvIr(xr
HotKeyMask=0; :WRD<D_4
KeyCount--; uzxwJs'fz
} 1{M?_~g4
} y CHOg
} VKPEoy8H
} i1x4$}
*w;?&)8%
BOOL CHookApp::InitInstance() S
}`f&
{ f2c<-}wR
AFX_MANAGE_STATE(AfxGetStaticModuleState()); .QP`Qn6 (P
hins=AfxGetInstanceHandle(); fBh"
InitHotkey(); h
8$.mQr
return CWinApp::InitInstance(); U LS>v
} B!mHO*g
3PkZXeH/
int CHookApp::ExitInstance() $Z;8@O3
{ 0y$VPgsKf
VerifyWindow(); 7l7VT?<:
UnInit(); sq=EL+=j
return CWinApp::ExitInstance(); b;
of9hY
} Hx6ODj[-
]0'cdC
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file r??_2>Q
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) E"*E[>
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ D`QMlRzXy
#if _MSC_VER > 1000 J,,VKA&
#pragma once 9U;
#endif // _MSC_VER > 1000 Yp(0 XP5o
<U$YJtEK
class CCaptureDlg : public CDialog 1M`>;fjYa
{ <SJ6<'
// Construction 7[=G;2<
public: 8qkQ*uJP
BOOL bTray; dm/3{\ 4
BOOL bRegistered; 7W}%ralkg
BOOL RegisterHotkey(); !F s$W
UCHAR cKey; %qcCv9
UCHAR cMask; D'[:35z
void DeleteIcon(); wDi/oH/H
void AddIcon(); vKnZ= =B
UINT nCount; *JImP9SE
void SaveBmp(); mD>
J,E
CCaptureDlg(CWnd* pParent = NULL); // standard constructor PW@ :fM:q
// Dialog Data [>`.,k
//{{AFX_DATA(CCaptureDlg) W'9{2h6u(
enum { IDD = IDD_CAPTURE_DIALOG }; TAh'u|{u2
CComboBox m_Key; H,c1&hb/w
BOOL m_bControl; *-*V>ntvT$
BOOL m_bAlt; _886>^b@
BOOL m_bShift; RCfeIHL
CString m_Path; >A{e,&