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:
XG6UV('
PJcz] < 一、实现方法
rNHV fI(H
:N 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:
*r3u=oWb I=`efc]T #pragma data_seg("shareddata")
QeAkuqT'[ HHOOK hHook =NULL; //钩子句柄
1<9m^9_ro UINT nHookCount =0; //挂接的程序数目
y+[wlo&WC static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
z3}4+~~ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
2|^bDg;W+u static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
Y|i!\Ae static int KeyCount =0;
;,&1 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
)@Yr HS4 #pragma data_seg()
D#9W [6 >G+?X+9 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。
hMs}r,* M*c`@\ 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:
:@X@8j": I1(,J BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
Ts:pk cKey,UCHAR cMask)
hMx/}Tw wt {
<BN)>NqM BOOL bAdded=FALSE;
~#~Kxh for(int index=0;index<MAX_KEY;index++){
Ad7=JzV if(hCallWnd[index]==0){
P3YG:* hCallWnd[index]=hWnd;
_zO,VL HotKey[index]=cKey;
J`3pXc$. HotKeyMask[index]=cMask;
Zt[1RMO bAdded=TRUE;
',*
6vbII KeyCount++;
{4{ACp break;
MgLz:2
:F }
8YBsYKC }
m[u
6<C return bAdded;
A]vQ1*pnk }
`}u~nu< //删除热键
>b/0i$8 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
#H1yjJQ /x {
T[eTT]Z{Ia BOOL bRemoved=FALSE;
%P9Zx!i> for(int index=0;index<MAX_KEY;index++){
B)"WG7W E if(hCallWnd[index]==hWnd){
S?=2GY if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
UeT"v?zP hCallWnd[index]=NULL;
_B|g)Rdv HotKey[index]=0;
HWGlC < HotKeyMask[index]=0;
e:.Xs bRemoved=TRUE;
4 ITSDx KeyCount--;
Fk
1M5Dm break;
F+AShh }
BZx#@356N }
_Oq (&I }
YKUs>tQ! return bRemoved;
Ph.$]yQCc] }
te'<xfG '89D62\89 Oy[t}*Ik DLL中的钩子函数如下:
JX/rAnc@ KFC zf_P! LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
)mZ`j. {
q@u$I'`Bs BOOL bProcessed=FALSE;
+]|J if(HC_ACTION==nCode)
=J?<M?ugf {
$-
#M~eZv if((lParam&0xc0000000)==0xc0000000){// 有键松开
poHDA=#
3 switch(wParam)
/sdkQ{J!. {
Ar=pzQ<Z{ case VK_MENU:
8N8B${X MaskBits&=~ALTBIT;
hgKs[ySo,3 break;
<v[,A8Q case VK_CONTROL:
o,Ew7~u MaskBits&=~CTRLBIT;
m&|?mTo>m break;
T0RgCU
IV case VK_SHIFT:
;Z.}~d6>! MaskBits&=~SHIFTBIT;
R_4600 break;
Mk[_yqoCO default: //judge the key and send message
it>FG9hVo break;
Jp5~iC2d }
]Wv\$JXI for(int index=0;index<MAX_KEY;index++){
FQ(=Fnqn if(hCallWnd[index]==NULL)
h.~S^uKi* continue;
JYKA@sZHe if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
94|BSxc {
rxCuV SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
-\>Bphu,y bProcessed=TRUE;
+\.gd L) }
w>VM-- }
18ci-W#p }
c+|,2e
0T else if((lParam&0xc000ffff)==1){ //有键按下
$o1Gxz switch(wParam)
r"U$udwjg {
G*Z4~-E4* case VK_MENU:
{n%F^ky+7 MaskBits|=ALTBIT;
XRj<2U5 break;
-@L*i|A case VK_CONTROL:
U4zyhj MaskBits|=CTRLBIT;
v D}y%} break;
5oWR}qqFK case VK_SHIFT:
iu&'v MaskBits|=SHIFTBIT;
qz(0iZ] Y break;
r#3_F=xL5 default: //judge the key and send message
b^5rV5d break;
tX Z5oG7 }
=}U`q3k for(int index=0;index<MAX_KEY;index++){
i6(y Bn if(hCallWnd[index]==NULL)
c<-_Vh.:5 continue;
1c+[S]7rY if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
H-0A&oG {
(?YTQ8QR SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
i>q]U:U bProcessed=TRUE;
Kv!CL9^LX7 }
) <^9` }
SukRJvi }
E@P8-x'i if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
hq$:62NYg for(int index=0;index<MAX_KEY;index++){
+vBq,'k` if(hCallWnd[index]==NULL)
d5+ (@HSR continue;
pz@_%IUS if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
srJ,Jr( SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
*V3 }L
Z //lParam的意义可看MSDN中WM_KEYDOWN部分
;VYL7Xu]( }
^0A'XCULG }
+;pdG[N }
p@NE^aMn return CallNextHookEx( hHook, nCode, wParam, lParam );
nXk<DlTws }
6
}qNH29 q9yY% 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:
@B*?owba> >Ex\j? BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
2\lUaC#E BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
-`FTWH !ZD[ $lt+ 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
ZVVK:dDgt X@5!I+u\L LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
^'*9,.ltd {
Mfuw y if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
Bj;Fy9[yb {
PDzVXLpC //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
u==bLl=$ SaveBmp();
H)G ^ Y1 return FALSE;
O:q 0- }
{SbA(a?B …… //其它处理及默认处理
{1>V~e8t }
[&j!g g(>;Z@Y
c*9RzD#Zj 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。
;Q:^|Fw!F ~aNK)<Fznd 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。
k6QQoLb$V ~:D}L 二、编程步骤
O (<Wn- uw&GXOzew9 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
8sx\b r,A750P^ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
ABSAle ;KWR/?ec 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
8h78Zb&[ W0K&mBu 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
5qGRz"\p~ ^g$k4 5、 添加代码,编译运行程序。
[kMXr'TyPX
^GB9!d. 三、程序代码
h$_Wh( UsNr$MO
{ ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
-:Nowb #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
8G?'F${` #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
7,d^?.~S #if _MSC_VER > 1000
KCGs*kp> #pragma once
t IdH?x #endif // _MSC_VER > 1000
KIps{_J[< #ifndef __AFXWIN_H__
$Ud-aRlD #error include 'stdafx.h' before including this file for PCH
4~53%=+ #endif
cmmH)6c> #include "resource.h" // main symbols
tY C`?HT class CHookApp : public CWinApp
gz;( ).{ {
j/5>zS public:
WOZf4X`[ CHookApp();
f"~+mO // Overrides
KwlN // ClassWizard generated virtual function overrides
>&f .^p //{{AFX_VIRTUAL(CHookApp)
p{"p<XFyO public:
#r `hK) virtual BOOL InitInstance();
{d.`0v9h virtual int ExitInstance();
?C(Z\"IX //}}AFX_VIRTUAL
|xG|HJm, //{{AFX_MSG(CHookApp)
yb2*K+Kv // NOTE - the ClassWizard will add and remove member functions here.
L%ND?'@ // DO NOT EDIT what you see in these blocks of generated code !
JUok@6 //}}AFX_MSG
su<_?'uH DECLARE_MESSAGE_MAP()
y,tA~ };
$NJ]2P9L LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
!bFa\6]q BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
r*C:)z.} BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
pM9Hav@iWU BOOL InitHotkey();
I1=YSi;A BOOL UnInit();
L01R.3Z+ #endif
a5{CkM&,( 7uFM)b@.P //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
j01.`G7Q #include "stdafx.h"
b#FN3AsR #include "hook.h"
%;(+s7 #include <windowsx.h>
j
wlmWO6 #ifdef _DEBUG
Y.sf^} #define new DEBUG_NEW
[-bL>8 #undef THIS_FILE
WZ&/l 65J static char THIS_FILE[] = __FILE__;
HNxJ`x~Z~ #endif
BP6;dF5E #define MAX_KEY 100
XL_X0(AKf #define CTRLBIT 0x04
&STgj|t_ #define ALTBIT 0x02
u`$,S&Er #define SHIFTBIT 0x01
0PE $n #pragma data_seg("shareddata")
9Xmb_@7b} HHOOK hHook =NULL;
zkYlIUD UINT nHookCount =0;
<~!7? ak static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
I&3L1rl3{* static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
81V,yq] static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
_SjS^z~ static int KeyCount =0;
Hq8<g$ static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
R!lNm,i #pragma data_seg()
8)&yjY HINSTANCE hins;
W}EI gVHs void VerifyWindow();
2w)0>Y(_ BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
%gSqc
}v* //{{AFX_MSG_MAP(CHookApp)
us\@n" // NOTE - the ClassWizard will add and remove mapping macros here.
L.$9ernVY // DO NOT EDIT what you see in these blocks of generated code!
{g@Wd2-J} //}}AFX_MSG_MAP
:T"!6; END_MESSAGE_MAP()
S;M'qwN z11;r]VI CHookApp::CHookApp()
Kg=TPNf"$ {
8kXbyKX[b // TODO: add construction code here,
J4 .C"v0a // Place all significant initialization in InitInstance
FSoL|lH }
@y[Zr6\z 5(q\x(N CHookApp theApp;
[bUM x LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
"zc@(OA[z {
p<?~~7V BOOL bProcessed=FALSE;
p<Wb^BE if(HC_ACTION==nCode)
YR'?fr {
o<1e- if((lParam&0xc0000000)==0xc0000000){// Key up
7)O?jc switch(wParam)
:k6|-A2 {
5)'
_3r case VK_MENU:
/p~"?9b[ i MaskBits&=~ALTBIT;
$"0t 1 break;
U2 <*BRJ case VK_CONTROL:
gZuk( MaskBits&=~CTRLBIT;
VQU [5C break;
EXH{3E54)` case VK_SHIFT:
B)O=wx MaskBits&=~SHIFTBIT;
#HWz.Wb break;
iC?s`c0B default: //judge the key and send message
1>jG*tr break;
e
&^BPzg }
}X$vriW for(int index=0;index<MAX_KEY;index++){
fO[X<|9 if(hCallWnd[index]==NULL)
hhlQ!WV2 continue;
q -M&f@Il if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
OOQfa#~k {
(9*s:)zD- SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
0&=2+=[c bProcessed=TRUE;
nQdNXv<( }
nL5Gr:SLo }
bxyEn'vNvQ }
j|FGb: else if((lParam&0xc000ffff)==1){ //Key down
>hoIJZP, switch(wParam)
;38W41d{ {
`~UCWK case VK_MENU:
I+D`\OSL MaskBits|=ALTBIT;
-b~MQ/,2 break;
jV\M`=4IC case VK_CONTROL:
u><ax MaskBits|=CTRLBIT;
bR?-B>EB break;
'G>Ejh@t case VK_SHIFT:
LTp5T|O MaskBits|=SHIFTBIT;
1)/B V{n break;
F+*>q default: //judge the key and send message
Qc;`nck break;
_DMj)enH" }
vVc:[i for(int index=0;index<MAX_KEY;index++)
jz't!wj {
<Xm5re. if(hCallWnd[index]==NULL)
9<kKno continue;
4U<'3~RN if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
:>nk63V ( {
B
h@R9O< SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Ox?LVRvxI bProcessed=TRUE;
IE$x2==) }
EAF<PMb }
?*u)T%S }
EhEn|%S if(!bProcessed){
>4ebvM
0| for(int index=0;index<MAX_KEY;index++){
*0{MAm if(hCallWnd[index]==NULL)
Xx:0Nt] continue;
`=uCp^+v if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
M$FXDyr SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
|o~FKy1'z\ }
\-GV8A2:k }
.2Q`. o) }
c[!e*n!y return CallNextHookEx( hHook, nCode, wParam, lParam );
+6*oO| }
4en&EWUr NhCO C BOOL InitHotkey()
V J){@ {
7$x@;%xd if(hHook!=NULL){
5U|f"3&8 nHookCount++;
y
97QqQ^ return TRUE;
Z@
h<xo*r }
9XT6Gf56 else
*{Wh-bc hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
vMzR3@4e if(hHook!=NULL)
+hY/4Tx< nHookCount++;
;&WN%L* return (hHook!=NULL);
]WN{8 }
u):z1b3*? BOOL UnInit()
eWqJ 2Tt {
aZ=WK4 if(nHookCount>1){
#Q 2$v; nHookCount--;
-ud~'<k
return TRUE;
:eQ@I+ }
hrZ~7 0r BOOL unhooked = UnhookWindowsHookEx(hHook);
da\K>An> if(unhooked==TRUE){
LN?T$H nHookCount=0;
&BG^:4b hHook=NULL;
U( W#H| }
@WhcY*R2 return unhooked;
7Yk6C5C }
&lBfW$PZjk bT[Q:#GL BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
J9/9k {
A!fjw BOOL bAdded=FALSE;
|t]-a%A=w for(int index=0;index<MAX_KEY;index++){
eX?o4> if(hCallWnd[index]==0){
XZd !c Ff hCallWnd[index]=hWnd;
k49CS*I HotKey[index]=cKey;
-jC. dz HotKeyMask[index]=cMask;
Rr%]/% bAdded=TRUE;
Lrq+0dI 65 KeyCount++;
8k_,Hni break;
4DuZF
-y }
"kP.Kx! }
}y=7r!{@ return bAdded;
rRT9)wDa }
S31:} bn<&Xe BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
CFul_qZ/e {
(d#?\ BOOL bRemoved=FALSE;
9!2KpuWji for(int index=0;index<MAX_KEY;index++){
)/
s9ty if(hCallWnd[index]==hWnd){
Vy}:Q[ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
g'pE z hCallWnd[index]=NULL;
`Yoafa HotKey[index]=0;
EHzU`('?[ HotKeyMask[index]=0;
9!bD|-6y bRemoved=TRUE;
M/UJb1< KeyCount--;
]PUyX8'~ break;
}{iR+MX }
l*nSgUg }
Oo7n_h1 }
@Z3b^G[ return bRemoved;
Yo7ctwzdH; }
%NeKDE Hd;>k$B void VerifyWindow()
HD=WHT& {
O,^,G<` for(int i=0;i<MAX_KEY;i++){
>^<qke if(hCallWnd
!=NULL){ ,0-
if(!IsWindow(hCallWnd)){ +BzKO >
hCallWnd=NULL; F<'g6f
HotKey=0; (B$2)yZY
HotKeyMask=0; AqN(htGvx
KeyCount--; Onot<}K
} -(:BkA
} _9L2JN$R6
} vja^O
} x!I7vs~~zW
m{b(^K9}
BOOL CHookApp::InitInstance() cG"jrQ
{ z2"2Xqy<U
AFX_MANAGE_STATE(AfxGetStaticModuleState()); @Ki`g(],P
hins=AfxGetInstanceHandle(); u;=("S{"0
InitHotkey(); 7RdL/21K
return CWinApp::InitInstance(); bE0S)b)
} X-n'?=
z#,?*v
int CHookApp::ExitInstance() .Ta$@sP h}
{ zlSwKd(
VerifyWindow(); ]&}?J:+?0E
UnInit(); g{<3*,
return CWinApp::ExitInstance(); |W#^L`!G
} oxGOn('
Ma{|+\Q.Z
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file pdtK3Pf
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) WBC'~ h<@
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ .bpxSU%X
#if _MSC_VER > 1000 t$Qav>D
#pragma once kP[ Y
#endif // _MSC_VER > 1000 ;|
\Ojuf
;Vp&f%u+v
class CCaptureDlg : public CDialog Kx<