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:
%)BwE
i5.?g <.H 一、实现方法
.4H_Zt[2 dFdlB`L 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:
W+8BQ-2 u)tHOV>& #pragma data_seg("shareddata")
N[0
xqQ HHOOK hHook =NULL; //钩子句柄
T"n>h UINT nHookCount =0; //挂接的程序数目
TNyK@~#m static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
f#'8"ff*1 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
AGl|>f) static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
v&p,Clt-2 static int KeyCount =0;
kw6cFz static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
olYPlHF #pragma data_seg()
"kcpA#uD| 6e-#XCR{ 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。
$dlnmNP+ gsLr= DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
ov?.:M "}0)YRz% BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
+R2^*
*< cKey,UCHAR cMask)
a];BW)
{
I~d#p ]> BOOL bAdded=FALSE;
F9Ifw><XM for(int index=0;index<MAX_KEY;index++){
's$A+8;L if(hCallWnd[index]==0){
NE$VeW+@ hCallWnd[index]=hWnd;
#=`FM:WH HotKey[index]=cKey;
'9IP; HotKeyMask[index]=cMask;
~!8%_J _ bAdded=TRUE;
n^* >a KeyCount++;
@*CAn(@#N break;
>r;ABz/ }
R#"U/8b>z }
xIS\4]F?r return bAdded;
gV<0Hj }
@PT`CK} //删除热键
qgwv=5| BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
"V*kOb&'*Z {
8|w5QvCU?3 BOOL bRemoved=FALSE;
jz{(q; for(int index=0;index<MAX_KEY;index++){
xP8iz?6"V if(hCallWnd[index]==hWnd){
(:_%kmu if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
ybD{4&ZE hCallWnd[index]=NULL;
l4iuu HotKey[index]=0;
)$ ofl%+ HotKeyMask[index]=0;
aEcktg6h bRemoved=TRUE;
>&$ $(Bp KeyCount--;
mgJShn8] break;
*Gg1h@& }
di-O*ug }
Aivu %}_| }
*Te4U5F return bRemoved;
6Y;Y}E }
S
23S.]r X)`(nj =giM@MV DLL中的钩子函数如下:
/Oq1q._9F hg[l{)Q LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
1$:{{% {
XX]5T`D BOOL bProcessed=FALSE;
DePV,. if(HC_ACTION==nCode)
MILIu;[{#r {
z5x,fQw6O if((lParam&0xc0000000)==0xc0000000){// 有键松开
AzHIp^ switch(wParam)
P`\m9"7 {
S/@dkHI' case VK_MENU:
B'G*y2UnG MaskBits&=~ALTBIT;
/2g)Z!&+L break;
%k/
k]:s case VK_CONTROL:
iYO
wB'z MaskBits&=~CTRLBIT;
(t]lP/
break;
L eG7x7n case VK_SHIFT:
r[.zLXgK MaskBits&=~SHIFTBIT;
N oX_? break;
o7_MMeQ4 default: //judge the key and send message
J{nyo1A break;
Nb^zkg }
Rz<d%C;R for(int index=0;index<MAX_KEY;index++){
A2g"=x[1@K if(hCallWnd[index]==NULL)
}XfS#Xr1aV continue;
o9U0kI=W if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
GNhtnB {
6MLN>)t SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
6.
+[
z bProcessed=TRUE;
2+T 8Y,g }
n:5O9,umZ }
$\YLmG }
E3CiZ4=5 else if((lParam&0xc000ffff)==1){ //有键按下
"TBQNWZ switch(wParam)
iF#}t(CrH {
&rl]$Mtt case VK_MENU:
E1Ru)k{B MaskBits|=ALTBIT;
uPv;y!Lsa@ break;
>wg9YZ~8 case VK_CONTROL:
}@ O|RkY MaskBits|=CTRLBIT;
O84v*=u A break;
!1a|5
xrn case VK_SHIFT:
&;6|nl9; MaskBits|=SHIFTBIT;
|d/x~t= break;
*j_fG$10g default: //judge the key and send message
2FZ0c/[& break;
z:ru68 }
egxJ3. for(int index=0;index<MAX_KEY;index++){
)Dk0V!%N if(hCallWnd[index]==NULL)
cXLV"d continue;
%!ER @&1f& if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
(n":]8} {
WuP([8 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
X/`#5<x bProcessed=TRUE;
:/yr(V{ }
a'_MhJ zs }
\p>]G[g }
Y^c,mK^ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
X] JpS for(int index=0;index<MAX_KEY;index++){
C0t+Q if(hCallWnd[index]==NULL)
,E*a$cCw continue;
?RRSrr1 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
e6{[o@aM{ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
\J,- <wF //lParam的意义可看MSDN中WM_KEYDOWN部分
xY\*L:TwW }
DJ
mQZ+{2 }
(PsSE:r}+ }
RB lOTQjv return CallNextHookEx( hHook, nCode, wParam, lParam );
0_,3/EWa }
!_XU^A> \pewbu5^ 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:
#FQm/Q<0 )5GdvqA BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
hSx+{4PZ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
$+lz<~R 6yu*a_ 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
)F%wwc^r D_yY0rRM LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
:kp {
UALg!M# if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
&m%Pr {
PNxVW //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
6uCk0
B| SaveBmp();
Kbz7 return FALSE;
8CnI%_Su }
-KIVnV=&m …… //其它处理及默认处理
A<YZBR_ }
U2[3S\@ (jo(bbpj 86^ZYh 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
l# !@{ < j?f,~Y<k 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
g6@N PQ ^O$[Y9~*
二、编程步骤
+]S;U&vQ H4y1Hpa, 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";
So)KI_M (v'lb!j^# 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
_Y
><ih 0'\FrG 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@t,[ G3_mWppH 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;
YA;8uMqh; XD+cs.{5 5、 添加代码,编译运行程序。
CQ8o9A/ U&w5&W{F} 三、程序代码
j quSR= w}bEufU+2 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
+}(B856+ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
$^NWzc #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
WfTdD.Xx #if _MSC_VER > 1000
uG(~m_7Hx #pragma once
,s yA() #endif // _MSC_VER > 1000
rd"]@~v1 #ifndef __AFXWIN_H__
F;MT4*4 #error include 'stdafx.h' before including this file for PCH
<_sT]?N# #endif
cP#]n)< #include "resource.h" // main symbols
8Snq75Q< class CHookApp : public CWinApp
)HzITsFZKT {
ek{PA!9Sk public:
#o r7T^ CHookApp();
,$6MM6W;-F // Overrides
~\)&{' // ClassWizard generated virtual function overrides
d'AviW> //{{AFX_VIRTUAL(CHookApp)
E9Xk8w'+ public:
/_k hFw virtual BOOL InitInstance();
,],JI|Rl8c virtual int ExitInstance();
kXZV%mnT7 //}}AFX_VIRTUAL
UB&S 2g //{{AFX_MSG(CHookApp)
L
yA(. // NOTE - the ClassWizard will add and remove member functions here.
e\
l,gQP // DO NOT EDIT what you see in these blocks of generated code !
S)'q:`tZo //}}AFX_MSG
O 44IH`SI DECLARE_MESSAGE_MAP()
e}Af"LI };
vZ nO LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
H8t{ >C)] BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
<E}]t,'3 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
'9p5UC BOOL InitHotkey();
mk`cyN>m BOOL UnInit();
9Pob|UA #endif
a5U2[Ko80 bF Y)o Z //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
kkE)zF #include "stdafx.h"
$NGtxZp #include "hook.h"
bhm~Ii #include <windowsx.h>
$jeDVH #ifdef _DEBUG
(fGJP*YO #define new DEBUG_NEW
SVs~, #undef THIS_FILE
xwH|ryfs,Z static char THIS_FILE[] = __FILE__;
6dS1\Y #endif
ZnhuIAAG #define MAX_KEY 100
KEVy%AP=*h #define CTRLBIT 0x04
rd 35) #define ALTBIT 0x02
F{H0
% #define SHIFTBIT 0x01
f\F_?s)_y #pragma data_seg("shareddata")
?9r,Y;,H HHOOK hHook =NULL;
G}dOx}kT UINT nHookCount =0;
Lq
$4.l[j static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
2W:?#h3 static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
}b]y
0" static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
kJ<Xq
static int KeyCount =0;
f/[?5M[ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
;AL@<,8 #pragma data_seg()
tCCi|*P
G HINSTANCE hins;
U9p.Dh~)vG void VerifyWindow();
x{`<);CQ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
|7Xpb //{{AFX_MSG_MAP(CHookApp)
u FYQ^ // NOTE - the ClassWizard will add and remove mapping macros here.
#<i><EG // DO NOT EDIT what you see in these blocks of generated code!
.McoW7|Y //}}AFX_MSG_MAP
Lc: SqF END_MESSAGE_MAP()
p:Ld)U * =|5bhwU] CHookApp::CHookApp()
|3T|F3uEX
{
pffw5Tc // TODO: add construction code here,
ZLio8 // Place all significant initialization in InitInstance
MoR-8vnJ }
_M]rH<h f_P+qm CHookApp theApp;
Oi%~8J> LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
@~U6=(+ {
|8U7C\S[ BOOL bProcessed=FALSE;
Hv7D+j8M if(HC_ACTION==nCode)
}Keon.N? {
>RqT7n8h if((lParam&0xc0000000)==0xc0000000){// Key up
y:[VRLo switch(wParam)
I^\bS {
bb:|1D case VK_MENU:
nIqY}?? MaskBits&=~ALTBIT;
ttq< )4 break;
-^xKG'uth case VK_CONTROL:
J!fc)h MaskBits&=~CTRLBIT;
=#")G1A break;
19-yM`O case VK_SHIFT:
&Cpxo9- MaskBits&=~SHIFTBIT;
*DI:MBJY break;
}!7DF default: //judge the key and send message
RdVis|7o break;
K\E]X\: }
4C9"Q,o%& for(int index=0;index<MAX_KEY;index++){
R6@~ if(hCallWnd[index]==NULL)
a~eLkWnh<k continue;
}}bi#G:R+ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
b=
ec?n #7 {
:2Rci`lp SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
8J?`_ bProcessed=TRUE;
X-r,>o: }
!#4HGjPI }
kR~4O$riG }
mF:s-+ else if((lParam&0xc000ffff)==1){ //Key down
ABe^]HlH switch(wParam)
!2M[ {
2c`=S5 case VK_MENU:
F t8h= MaskBits|=ALTBIT;
f5qHBQ break;
D&6Qk&> case VK_CONTROL:
I
3,e)Z MaskBits|=CTRLBIT;
DoB3_=yJ+ break;
MG5Sn*(C case VK_SHIFT:
W]Tt8 MaskBits|=SHIFTBIT;
iK:qPrk- break;
-L50kk>h default: //judge the key and send message
P<JkRX break;
^5 =E`q". }
$JSC+o(q3# for(int index=0;index<MAX_KEY;index++)
QZa#iL {
P7.8tM2} if(hCallWnd[index]==NULL)
+X(^Q@ continue;
3pjYY$' if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Jas|P}{=fT {
{)gd|JV* SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
l3#dfW{ bProcessed=TRUE;
M9jo<+ }
-/2$P }
HYnq x>L ~ }
`ur9KP4Dq if(!bProcessed){
Ollv _o3 for(int index=0;index<MAX_KEY;index++){
'{k Nbx51 if(hCallWnd[index]==NULL)
YeVc,B' continue;
~
2oP, if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
:ItW| SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
2bxMIr }
H;Qn?^ }
q]%bd[zkz }
Fsj&/:
q return CallNextHookEx( hHook, nCode, wParam, lParam );
^(JbJ@m/ }
0THAI ~#km0<r? BOOL InitHotkey()
:.<TWBo V {
eo52X&I if(hHook!=NULL){
gWH9=%! nHookCount++;
LU7)F,ok return TRUE;
A.x}%v,E }
}w^ T9OC else
ZBq*<VtV hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
s1$#G!' if(hHook!=NULL)
Cj9O[ nHookCount++;
iT9Ex9RL return (hHook!=NULL);
(Tb0PzA }
|ylTy B BOOL UnInit()
dq/?&X {
5@A=,
GPUn if(nHookCount>1){
Q~!hr0
ZR nHookCount--;
`e=n(D return TRUE;
`'.x*MNF }
gH55caF< BOOL unhooked = UnhookWindowsHookEx(hHook);
CWsv#XOg] if(unhooked==TRUE){
7kpW1tjY nHookCount=0;
F S+^r\) hHook=NULL;
SWd[iD }
NKhR%H return unhooked;
u0hbM9U> }
z n8ig/C NG!Q< !Y BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
OmbKx&>YGz {
"$cT*}br BOOL bAdded=FALSE;
24/~gft for(int index=0;index<MAX_KEY;index++){
G-?9;w'@ if(hCallWnd[index]==0){
b<78K5' hCallWnd[index]=hWnd;
gO!h<1 ! HotKey[index]=cKey;
je3n'^m HotKeyMask[index]=cMask;
q=i<vcw
bAdded=TRUE;
LK/V]YG KeyCount++;
n$Fm~iPo, break;
H{zuIN/.1 }
W2Z]?l;vQQ }
Jxw:Jk
~ return bAdded;
U (7P X`1 }
2Lgvy/uN n<&R"89 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
&+^ Y>Ke {
<qY>d,+E' BOOL bRemoved=FALSE;
EXzNehO~e for(int index=0;index<MAX_KEY;index++){
[IA==B7 if(hCallWnd[index]==hWnd){
:FpBz~!a if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
6WcbJ_"mq hCallWnd[index]=NULL;
Qs X 59d HotKey[index]=0;
;*H~Yb0 HotKeyMask[index]=0;
E'6P>6l5 bRemoved=TRUE;
Qug'B KeyCount--;
>g0@ Bk break;
:.df( 1(RL }
e-)1K }
tSa%ZkS }
K#< Wt5 return bRemoved;
{5-{f=Rk }
k T>}(G|| :E`l(sI7J} void VerifyWindow()
h
l'k_<a* {
5B/\vLHg4 for(int i=0;i<MAX_KEY;i++){
FY*0gp if(hCallWnd
!=NULL){ Jo+C!kc
if(!IsWindow(hCallWnd)){ bl-s0Ax-
hCallWnd=NULL; jk}PucV
HotKey=0; &bu`\|V
HotKeyMask=0;
`.WKU"To
KeyCount--; 9GaER+d|
} 4\es@2 q
} /loNOutw
} Bd[Gsns
} gg_(%.>
x[6Bc
BOOL CHookApp::InitInstance() v"_#.!V
{ 4FdH:os
AFX_MANAGE_STATE(AfxGetStaticModuleState()); |JQKxvjT
hins=AfxGetInstanceHandle(); RE$-{i
InitHotkey(); f L?~1i =
return CWinApp::InitInstance(); muY^Fx
} L$Z_j()2
[_1G\z_iE
int CHookApp::ExitInstance() kO4~N-&
{ ^
?9
~R"
VerifyWindow(); !
NEq|Y
UnInit(); @$G
K<jl
return CWinApp::ExitInstance(); imQNfNm
} 2Jv4l$$;*
SX;IUvVE5
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file 1bs95Fh9Q
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) iO`f{?b
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ bYH_U4b
#if _MSC_VER > 1000 -v@^6bQVp
#pragma once q)zvePO#
#endif // _MSC_VER > 1000 %*=FLtBjo
G[,VPC=
class CCaptureDlg : public CDialog epm|pA*
{
b6BIDuRb
// Construction YO+d+5
public: q[K)bg{HB
BOOL bTray; m:CpDxzbf
BOOL bRegistered; SUhP
e+
BOOL RegisterHotkey(); ,Z"sh*
UCHAR cKey;
ond/e&1
UCHAR cMask; iJeT+}
void DeleteIcon(); }clNXtN
void AddIcon(); 5]+eLKXB
UINT nCount; &>{L"{
void SaveBmp(); | 'G$}]H
CCaptureDlg(CWnd* pParent = NULL); // standard constructor *CSFkWVa
// Dialog Data GssoT<Y)Z
//{{AFX_DATA(CCaptureDlg) zv@o-R$l
enum { IDD = IDD_CAPTURE_DIALOG }; o\[nGf C&
CComboBox m_Key; `#F>?g$2
BOOL m_bControl; uESHTX/[
BOOL m_bAlt; b\mN^P~>A
BOOL m_bShift; |lY8u~%
CString m_Path; -tZb\4kh
CString m_Number; K)ib{V(50
//}}AFX_DATA #*@Yil=1
// ClassWizard generated virtual function overrides '"a8<