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:
kou7_4oS
${wp}<u_ 一、实现方法
&?xmu204 /yY} .S 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:
+NvpYz jr#*;go #pragma data_seg("shareddata")
7D'D7=Z. HHOOK hHook =NULL; //钩子句柄
3a ZS1]/ UINT nHookCount =0; //挂接的程序数目
mtE+}b@(!& static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
Ar?ZU ASJ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
_T8S4s8q static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
9^Web~yi# static int KeyCount =0;
MI:%Eq static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
d`5AQfL& #pragma data_seg()
YvP62c \ 9~a 5R]x2
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。
P-8QXDdr &u6n5-!v 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:
=i;T?*@ !yq98I' BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
/P]N40_@ cKey,UCHAR cMask)
?(Plb&kR {
O2 + K BOOL bAdded=FALSE;
vfm Y>nr for(int index=0;index<MAX_KEY;index++){
!V/7q'&t= if(hCallWnd[index]==0){
2:nI4S hCallWnd[index]=hWnd;
"f~OC<GdYs HotKey[index]=cKey;
s6_i> HotKeyMask[index]=cMask;
b9-3 bAdded=TRUE;
iAXGf V KeyCount++;
lHTr7uF( break;
oZl%0Uy?9I }
15aPoxo> }
?q2Yk/P return bAdded;
BTG_c_?]e }
V+l7W //删除热键
'(N(k@>{ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
'<1Cta` {
Zp<#( OIu BOOL bRemoved=FALSE;
Q0x?OL] A for(int index=0;index<MAX_KEY;index++){
dIhfp7| if(hCallWnd[index]==hWnd){
F`{O if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
0,.|-OZ hCallWnd[index]=NULL;
M_r[wYt! HotKey[index]=0;
K3,PmI&W
HotKeyMask[index]=0;
oJ"D5d, bRemoved=TRUE;
!u
.n KeyCount--;
#
kNp); break;
O2="'w'kR }
~ kDJ-V }
'}bmDb* }
&o1k_!25 return bRemoved;
V*Xr}FE }
)"6"g9A v.u 5% e+VE FWz DLL中的钩子函数如下:
C>,> _
! R3P@,j LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
|Sua4~yL( {
y"U)&1 c% BOOL bProcessed=FALSE;
CY[3%7fv if(HC_ACTION==nCode)
$4)L~g| {
1~LfR if((lParam&0xc0000000)==0xc0000000){// 有键松开
v*<rNZI switch(wParam)
koD}o^U# {
0]=Bqyg case VK_MENU:
g)|vS>^~ MaskBits&=~ALTBIT;
734n1-F?I% break;
"*W# z case VK_CONTROL:
[fo#){3K MaskBits&=~CTRLBIT;
A^LS^!Jz break;
5IFzbL#q#f case VK_SHIFT:
+/]*ChrS MaskBits&=~SHIFTBIT;
}#g+~9UK break;
~
L>M-D4o default: //judge the key and send message
h%4UeL &F break;
;#0$iE }
D. x8=|; for(int index=0;index<MAX_KEY;index++){
gNA!)}m\ if(hCallWnd[index]==NULL)
unbIfl= continue;
p0]\QM l1 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
9d(#/n {
D<<q5gG SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Wv;,@xTZ bProcessed=TRUE;
vX}w_Jj> }
<8Nr;96IA }
8pftc) k }
fk>{ else if((lParam&0xc000ffff)==1){ //有键按下
;c DMcKKIA switch(wParam)
rX>b R/ {
I|<]>D -8 case VK_MENU:
&rPAW V'v MaskBits|=ALTBIT;
GU/-L<g break;
P4eH:0=# case VK_CONTROL:
`<|<1, MaskBits|=CTRLBIT;
|>m'szca4 break;
8c_X`0jy case VK_SHIFT:
[/VpvQ' MaskBits|=SHIFTBIT;
X-,oL.:c break;
RO%M9LISI default: //judge the key and send message
!y'>sAf break;
Ht\2 IP }
v&WK9F\ for(int index=0;index<MAX_KEY;index++){
H270)Cwn+ if(hCallWnd[index]==NULL)
k*\)z\f continue;
gFu,q`Vf* if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
J]{<Z?% {
z,2*3Be6V SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
$ Y^0l bProcessed=TRUE;
) jvI Nb }
re}PpXRC }
1,Mm+_)B }
&/)B d% if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
8"-=+w.CZ for(int index=0;index<MAX_KEY;index++){
~/z%yg if(hCallWnd[index]==NULL)
~w|h;*Bj continue;
'gg<)Bd if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
yG7H>LF?8 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
^~7Mv^A //lParam的意义可看MSDN中WM_KEYDOWN部分
:l1-s] }
fiD,HGx
i }
B$x@I\(M }
S_OtY]gF return CallNextHookEx( hHook, nCode, wParam, lParam );
BT_XqO }
*n7=m=%) HX}B#T 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
/93z3o7D> A*81}P_ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
@o^$/AE? BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
}HmkTk P3Lsfi. 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
CV\y60n o|c6=77043 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
vf+z0df {
M"/Jn[ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
jX(${j< {
\)wch P_0 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
WWZ<[[ > SaveBmp();
(FaYagD return FALSE;
bDJ!Fc/ }
q1x[hv3
pP …… //其它处理及默认处理
G e]NA]< }
tgi%#8ZDpz vR2);ywX r=vY-p 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。
5$HG#2"Kb# kD%MFT4 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
y %61xA`# bu_@A^ys 二、编程步骤
^"54Q^SH |uw48*t 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
r^<,f[yH V&vG.HAT 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
V\{@c%xW fR'!p: ~ 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
bn8maYUZ fHEIys,{ 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
z5(5\j] "c]9Q% 5、 添加代码,编译运行程序。
^v cnDi GA[D@Wy 三、程序代码
h-;> v. <jF&+[*iT ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
S Z/yijf #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
izaqEz #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
3HYdb|y #if _MSC_VER > 1000
a3\~AO H% #pragma once
,IqE<i!U #endif // _MSC_VER > 1000
!&g_hmnIF #ifndef __AFXWIN_H__
,pdzi9@=t #error include 'stdafx.h' before including this file for PCH
&y=OZ
!M #endif
3%1wQXr0 #include "resource.h" // main symbols
)j~{P class CHookApp : public CWinApp
K{/i2^4 {
t,8?Tf+i public:
<3@nv% CHookApp();
O TlqJ // Overrides
oST)E5X;7 // ClassWizard generated virtual function overrides
eLORG(;h4 //{{AFX_VIRTUAL(CHookApp)
@-\=`#C** public:
xZ;eV76 virtual BOOL InitInstance();
Tgtym"=xd virtual int ExitInstance();
~K3Lbd|
r //}}AFX_VIRTUAL
/}>8|#U3y //{{AFX_MSG(CHookApp)
wzd(=*N // NOTE - the ClassWizard will add and remove member functions here.
2)|=+DN; // DO NOT EDIT what you see in these blocks of generated code !
GQY"
+xa8] //}}AFX_MSG
jLI1Ed DECLARE_MESSAGE_MAP()
2\k!DF };
\y=28KKc:c LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
l9=Ka{$^* BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
;w"h n* BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
bO/r1W BOOL InitHotkey();
Dbj?l;'1 BOOL UnInit();
(Z?f eUxp #endif
nA("
cD[, yx-"&K=` //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
:LNZC,-f}5 #include "stdafx.h"
Is3Y>oX #include "hook.h"
cyB+(jLHDs #include <windowsx.h>
XIbxi #ifdef _DEBUG
85Yi2+8f4 #define new DEBUG_NEW
'[F`!X #undef THIS_FILE
.*njgAq7 static char THIS_FILE[] = __FILE__;
\-6y#R-B #endif
^"
g?m #define MAX_KEY 100
mIYKzu_k= #define CTRLBIT 0x04
z8}QXXa #define ALTBIT 0x02
\9#f:8Q #define SHIFTBIT 0x01
9v*y&V9/ #pragma data_seg("shareddata")
JluA?B7E HHOOK hHook =NULL;
Tr:@Dv.O UINT nHookCount =0;
oYf+I static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
juWXB+d2Y static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
S$fS|N3]% static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
jFe8s@7 static int KeyCount =0;
=UK:83R( static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
E2w-b^,5 #pragma data_seg()
)rj!/% HINSTANCE hins;
K g#Bg## void VerifyWindow();
Aqf91
[c BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
_$@fCo0 //{{AFX_MSG_MAP(CHookApp)
ineSo8| @ // NOTE - the ClassWizard will add and remove mapping macros here.
27c0wzq // DO NOT EDIT what you see in these blocks of generated code!
wk8fa //}}AFX_MSG_MAP
kjV>\e END_MESSAGE_MAP()
VgYy7\?p {[Ri:^nHgL CHookApp::CHookApp()
T?!SEblP] {
l6w\E=K // TODO: add construction code here,
>\pF5a` // Place all significant initialization in InitInstance
P(7el }
Qfy_@w] Ji!i}UjD7! CHookApp theApp;
i_AD3Jrs LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
i>h3UIx\ {
O*?^a7Z)4 BOOL bProcessed=FALSE;
5ILKYUg, if(HC_ACTION==nCode)
R,PN?aj {
sgK =eBE if((lParam&0xc0000000)==0xc0000000){// Key up
t/O^7)% switch(wParam)
?;P6#ByR {
We}9'X} case VK_MENU:
44P [P{y MaskBits&=~ALTBIT;
n5A|Zjk; break;
M=;csazN case VK_CONTROL:
{%>~
]9E MaskBits&=~CTRLBIT;
gE@Pb break;
Y]`=cR`/" case VK_SHIFT:
XZ@+aG_%q MaskBits&=~SHIFTBIT;
_('
@'r break;
3Q62H+MC default: //judge the key and send message
B\rY\ break;
jJ<&!= }
'\8YH+%It for(int index=0;index<MAX_KEY;index++){
[Ca''JqrA if(hCallWnd[index]==NULL)
l6WEx
-d continue;
DIQ30(MS if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
iH-,l {
2RNee@!JJP SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
p2b~k[ bProcessed=TRUE;
L7rr/D }
5TuwXz1v }
[T7&)p }
K*Ba;"Ugeg else if((lParam&0xc000ffff)==1){ //Key down
-wC}JVVcK switch(wParam)
Y_y!$jd(N {
iY@}Q " case VK_MENU:
CXoiA"P MaskBits|=ALTBIT;
WQVU 82b* break;
*.wj3'wV case VK_CONTROL:
:EHk]Hkz
MaskBits|=CTRLBIT;
DpmAB. break;
b&h'>( case VK_SHIFT:
]=-=D9ZS3 MaskBits|=SHIFTBIT;
@(6i 1Iwu9 break;
8(K:2 default: //judge the key and send message
,R-k]^O break;
wVf 7<@/y }
mk~CE for(int index=0;index<MAX_KEY;index++)
MhE".ZRd {
L6nsVL& if(hCallWnd[index]==NULL)
F^Jz
continue;
k^K76m B if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
o ?05bv {
g fAWN SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
S m=ln)G= bProcessed=TRUE;
\^y~w~g? }
X}3?k<m }
v:74iB$i/C }
RLQ*&[A} if(!bProcessed){
OMjPC_ for(int index=0;index<MAX_KEY;index++){
hC<E4+5., if(hCallWnd[index]==NULL)
mpwh= continue;
R|qNyNXo[ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
z@19gD#8 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
4|\M`T }
\oxf_4X }
ShV_8F z }
5 8;OTDR! return CallNextHookEx( hHook, nCode, wParam, lParam );
CfrO1i F }
& }j;SK5 h0~<(3zC BOOL InitHotkey()
5WfZd {
CL5^>.} if(hHook!=NULL){
4PS| nHookCount++;
p</t##]3ks return TRUE;
8kU(>' ^_: }
q*4@d)_& else
'Tqusr>lPY hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
n9&fH if(hHook!=NULL)
`]GL3cIh: nHookCount++;
ti1R6oSn return (hHook!=NULL);
V :5aq.o! }
};9/J3]m BOOL UnInit()
*tpS6{4=#7 {
A9ld9R if(nHookCount>1){
4<1V nHookCount--;
1l^[%0 return TRUE;
t6-fG/Kc }
xgNV0;g, BOOL unhooked = UnhookWindowsHookEx(hHook);
U5cbO{\3I if(unhooked==TRUE){
Z&H_+u3j nHookCount=0;
}8"i~>>a hHook=NULL;
%UooZO }
# 7dvT= return unhooked;
wt@TR~a }
IR2Qc6+{ @0H0!9' BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Bo
ywgL| {
6f#Mi+" BOOL bAdded=FALSE;
6_yatq5c for(int index=0;index<MAX_KEY;index++){
GYJ j$' if(hCallWnd[index]==0){
&y73^"% hCallWnd[index]=hWnd;
NhYUSk ~u HotKey[index]=cKey;
X[w]aJnAr HotKeyMask[index]=cMask;
_RzoXn{1e bAdded=TRUE;
[Ax:gj KeyCount++;
n3U|
d+ break;
4J=6U&b }
JCZ&TK }
69ycP( return bAdded;
/:\27n }
dKDCJt]t
W>{&"
5 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
>N`,
3;Z {
c-.F{~ BOOL bRemoved=FALSE;
v1 ?G for(int index=0;index<MAX_KEY;index++){
~tW<]l7 if(hCallWnd[index]==hWnd){
#
E8?2] if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
+W-b3R:1> hCallWnd[index]=NULL;
jL3
*m HotKey[index]=0;
wLO"[, HotKeyMask[index]=0;
dR,a0+! bRemoved=TRUE;
zC[LcC*+J KeyCount--;
eo!+UFZbY break;
Ym
-U{a }
=/ !A }
0@u{(m }
p!Tac%D+k return bRemoved;
Ft :_6T% }
:m'(8s8 Bv*VNfUm void VerifyWindow()
%%wngiz\ {
#t# S(A9) for(int i=0;i<MAX_KEY;i++){
ecvZwL if(hCallWnd
!=NULL){ 9/&1lFKJ
if(!IsWindow(hCallWnd)){ RJT55Rv{
hCallWnd=NULL; l9y %@7
HotKey=0; :G^4/A_
HotKeyMask=0; '}>8+vU`
KeyCount--; O7&OCo|b%>
} fR2,NKM@
} oc-o>H
} j~;y~Cx?
} l<"B[
G[zy sxd
BOOL CHookApp::InitInstance() mkBQTQGT
{ .rDao]K
AFX_MANAGE_STATE(AfxGetStaticModuleState()); C<^S$
hins=AfxGetInstanceHandle(); b3GTsX\2|
InitHotkey(); &s\,+d0
return CWinApp::InitInstance(); ^b.fci{1m
} <X97W\
+@@( C9
int CHookApp::ExitInstance() 5':j=KQE_
{ h=NXU9n%'
VerifyWindow(); q}g0-Da
UnInit(); VF7H0XR/k5
return CWinApp::ExitInstance(); wmP[\^c%$j
} `"iPJw14
qX[C%
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file LzB*d
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) jM'Fb.>~
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ D2:ShyYAS
#if _MSC_VER > 1000 k5)IBO
#pragma once 3VQmo\li
#endif // _MSC_VER > 1000 oye/tEMG
d;r,?/C
class CCaptureDlg : public CDialog Z\)P|#L$
{ 7:.!R^5H
// Construction ;:)u
rI?
public: 6H|T )
BOOL bTray; WCI'Kh
BOOL bRegistered; PCKxo;bD
BOOL RegisterHotkey(); fjQIuM
UCHAR cKey; % <%r
UCHAR cMask; ,fm{
krE
void DeleteIcon(); TjctK [db@
void AddIcon(); KZ [:o,jp>
UINT nCount; }L5;=A']S
void SaveBmp(); MF::At[4
CCaptureDlg(CWnd* pParent = NULL); // standard constructor k@9q5lu;T
// Dialog Data xtXK3[s
//{{AFX_DATA(CCaptureDlg) U4e9[=q`'
enum { IDD = IDD_CAPTURE_DIALOG }; z-S8s2.Fd
CComboBox m_Key; `3UvKqe
BOOL m_bControl; ]RW*3X
BOOL m_bAlt; O=Vj*G,
BOOL m_bShift; 23zR0z (L
CString m_Path; DEzL] 1;P
CString m_Number; fvDcE]_%H
//}}AFX_DATA BUsAEwM
// ClassWizard generated virtual function overrides J \I`#
//{{AFX_VIRTUAL(CCaptureDlg) 6lxZo_
public: dSzq}w4xY
virtual BOOL PreTranslateMessage(MSG* pMsg); k0DX|O8mXV
protected: g aXF3v*j
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support p*Hf<)}
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); C2J@] &