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:
5=9gH
E>w|i 一、实现方法
=Ye I,KbA) `#>JRQ= 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:
\>(S?)6 $_b^p= #pragma data_seg("shareddata")
R9O[`~BA2 HHOOK hHook =NULL; //钩子句柄
il>XV> UINT nHookCount =0; //挂接的程序数目
rklK=W z static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
b2HHoIT static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
C4
@"@kbr static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
hYv;*] static int KeyCount =0;
bB"q0{9G- static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
qlIbnyP< #pragma data_seg()
50^T\u iJ 8I#
j+N 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
3hbUus lv0}d DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
b1frAA ^+q4* X6VB BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
Z<n%~z^ cKey,UCHAR cMask)
<%Afa# {
y|[YEY U) BOOL bAdded=FALSE;
L'$;;eM4 for(int index=0;index<MAX_KEY;index++){
rH5'+x K if(hCallWnd[index]==0){
CHNIL^B hCallWnd[index]=hWnd;
</7_T<He. HotKey[index]=cKey;
^ G@o} Z HotKeyMask[index]=cMask;
ZsepTtY bAdded=TRUE;
f1}b;JJTsv KeyCount++;
#\r5Q> break;
XoqmT/P }
?^W`7H F%0 }
0w<qj T^U return bAdded;
xlU:&=| }
=}Xw}X+[WY //删除热键
xyc`p[n& BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
%)@3V8 OI {
^=gzms BOOL bRemoved=FALSE;
?q+^U>wy& for(int index=0;index<MAX_KEY;index++){
TWAt)Q"J if(hCallWnd[index]==hWnd){
^Q""N< if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
BA cnFO hCallWnd[index]=NULL;
$Hbd:1%i
{ HotKey[index]=0;
VA0p1AD HotKeyMask[index]=0;
[^GXHE= bRemoved=TRUE;
Ve\=By-a| KeyCount--;
1!`B8y) break;
4Hcds9y9 }
mzh7E[S_,i }
Wo8.tu-2 }
Zfub+A return bRemoved;
hhynB^o }
+_E96`P tOf18V{a R2!_)Rpf DLL中的钩子函数如下:
NA9N#; 5fVm392+ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
#K_E/~ {
zM*PN|/%sH BOOL bProcessed=FALSE;
CH3bpZv if(HC_ACTION==nCode)
h|S6LgB {
_/
Uer} if((lParam&0xc0000000)==0xc0000000){// 有键松开
[j^c&}0 switch(wParam)
_
BUD~'Q5 {
qD/X% `>Q case VK_MENU:
.B|a.-oA4 MaskBits&=~ALTBIT;
M<"H1>q@ break;
e[AwR?= case VK_CONTROL:
xfJ&11fG2 MaskBits&=~CTRLBIT;
K{#1O=Gi break;
I3$/# case VK_SHIFT:
C~#ndl
Ij MaskBits&=~SHIFTBIT;
:ncR7:Z break;
y+.E} default: //judge the key and send message
yJ!x`RD),w break;
)RE~=*?d }
't:s6 for(int index=0;index<MAX_KEY;index++){
w~I;4p~(N if(hCallWnd[index]==NULL)
w`;>+_ E7 continue;
Jg\1(ix if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
/,cyp. {
AD/7k3: SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
~56F<=#, bProcessed=TRUE;
jWL;ElM' }
'z.:
e+Q_ }
C-6m[W8S }
4RXF.kJ3= else if((lParam&0xc000ffff)==1){ //有键按下
6EeK5XLf, switch(wParam)
tQ >
IJ {
A(<"oAe| case VK_MENU:
AJ`R2
$ MaskBits|=ALTBIT;
|?KdQeL break;
540,A,>:tb case VK_CONTROL:
|N/Wu9w$ MaskBits|=CTRLBIT;
v%6mH6V break;
:n t\uwh case VK_SHIFT:
g9$P J: MaskBits|=SHIFTBIT;
|zaYIVE[ break;
e//q`?ys default: //judge the key and send message
,\cO>y@ break;
`aw5"ns^V }
YPY'[j(p`n for(int index=0;index<MAX_KEY;index++){
b=-LQkcZhK if(hCallWnd[index]==NULL)
iB=v
>8l% continue;
<h"*"q|9 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
uNcE_< {
lh?TEQ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
r{~@hd'Aj bProcessed=TRUE;
-P5M(Rt }
O%n =n3 }
DKGZm<G> }
9:l@8^_o if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
R6KS&Ge_ for(int index=0;index<MAX_KEY;index++){
==z,vxr if(hCallWnd[index]==NULL)
;:)?@IuSy continue;
JG=U@I]
if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
h+rrmC SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
e%O]U:Z //lParam的意义可看MSDN中WM_KEYDOWN部分
0,x<@.pW }
EN!Q]O| }
:',Q6j( s }
~dO&e=6Hk return CallNextHookEx( hHook, nCode, wParam, lParam );
z2GT9 }
MCcWRbE5# ,n&e,I 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
`?PpzDV7Y %bs~%6) BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
9J!@,Zsh BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
5U3b&0 QNzx(IV@ 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
JZS#Q\JN %`~?w'
LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
HSR^R {
aybfBC if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
Dm.tYG {
=H\ig%%E@ //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
=!RlU)w SaveBmp();
ct3^V M&/ return FALSE;
=h{jF7 }
X!w&ib- …… //其它处理及默认处理
cG`R\$ }
du:%{4 JN
Ur?+g k^ZcgHHgb 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
nd 5w|83 ~e)`D nJ 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
50S >`qi2x =n}+p>\s 二、编程步骤
u=5~^ 9 %Z"I=;=nxI 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
+$YluGEJ #(5hV7i 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
u\JYxNj1 e I 6G 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;
qrj:H4#VB %z_PEqRj 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;
fs=W(~" :]viLw\&g 5、 添加代码,编译运行程序。
j(;o _qPd)V6yb 三、程序代码
^j1WF[GiSO BZP~m=kq ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
m'Thm{Y,?n #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
gUcG# #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
r3hUa4^97 #if _MSC_VER > 1000
MMI7FlfY #pragma once
iA^GA8dn #endif // _MSC_VER > 1000
XA$Z7_gu3 #ifndef __AFXWIN_H__
>c~Fgs #error include 'stdafx.h' before including this file for PCH
lAM"l)Ij #endif
Of*z9YI #include "resource.h" // main symbols
wd/"! A4( class CHookApp : public CWinApp
5 GP,J,J {
h zh%ML3L public:
wjr1?c CHookApp();
]y3'6! // Overrides
6uU2+I // ClassWizard generated virtual function overrides
-<'&"- //{{AFX_VIRTUAL(CHookApp)
>4zH\T! public:
#_,
l7q8U virtual BOOL InitInstance();
*W#_W]Tu virtual int ExitInstance();
nEZoF //}}AFX_VIRTUAL
^E5[~C*o3 //{{AFX_MSG(CHookApp)
jG0o-x=X // NOTE - the ClassWizard will add and remove member functions here.
rdFeDZo&Z) // DO NOT EDIT what you see in these blocks of generated code !
jtMN )TM //}}AFX_MSG
"Zh6j)[o DECLARE_MESSAGE_MAP()
c&Mci"nj0 };
d0`5zd@S LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
pm*6&, BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
+{$NN BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
FK$?8Jp BOOL InitHotkey();
&s|&cT BOOL UnInit();
.[Z<r> #endif
%U.aRSf/ \eD{bD //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
"v"w ER? #include "stdafx.h"
483BrFV #include "hook.h"
U-P\F- #include <windowsx.h>
gUoL8~ #ifdef _DEBUG
j&G*$/lTO6 #define new DEBUG_NEW
5df~] -=0Y #undef THIS_FILE
{~"&$DY2 static char THIS_FILE[] = __FILE__;
7h4"5GlO0 #endif
03iD(,@ #define MAX_KEY 100
*
7ki$f! #define CTRLBIT 0x04
RaS7IL:e #define ALTBIT 0x02
| 'SqG}h #define SHIFTBIT 0x01
uKI2KWU?2 #pragma data_seg("shareddata")
6QCU:2IiL HHOOK hHook =NULL;
BCE}Er& UINT nHookCount =0;
KT)A{i static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
(Ut)APM static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
.{-&3++WZ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
+$eEZ;4 static int KeyCount =0;
X676*;:!. static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
-`mHb #pragma data_seg()
PKT/U^2X] HINSTANCE hins;
(W7cQ> void VerifyWindow();
$)5F3a| BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
L{hP&8$k //{{AFX_MSG_MAP(CHookApp)
7>g^OE f // NOTE - the ClassWizard will add and remove mapping macros here.
_?M71>3$. // DO NOT EDIT what you see in these blocks of generated code!
s
uT#k3 //}}AFX_MSG_MAP
?#8s=t END_MESSAGE_MAP()
'g8~ uP Ie#LZti CHookApp::CHookApp()
W2F %E {
26YY1T\B) // TODO: add construction code here,
`&.]>H)N* // Place all significant initialization in InitInstance
AeqxH1 % }
-?A,N,nnX 2d,q?VH$ CHookApp theApp;
je^!W?U4< LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
,&II4;F {
!<wM?Q: BOOL bProcessed=FALSE;
hhTM-D1Ehs if(HC_ACTION==nCode)
=R08B)yR {
Rw$>()}H8 if((lParam&0xc0000000)==0xc0000000){// Key up
aj1o switch(wParam)
>Lh+(M;+F {
F[Dhj,C" case VK_MENU:
.=WsB@+ MaskBits&=~ALTBIT;
KJ
Gh) break;
SBnwlM"AN case VK_CONTROL:
0ciPH:V MaskBits&=~CTRLBIT;
kKV`9&dZe break;
wG1A]OJl1 case VK_SHIFT:
kI>Iq
Q-h MaskBits&=~SHIFTBIT;
@$R[Js%MuO break;
9rr"q5[ default: //judge the key and send message
dMAd-q5{ break;
C.r9)#G }
"#T3l^@ for(int index=0;index<MAX_KEY;index++){
1C [j:Ly/ if(hCallWnd[index]==NULL)
uTNmt] continue;
r-#23iT.~ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
f)xHSF" {
gDP\u<2! SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
KGCm@oy bProcessed=TRUE;
2TN+ (B#Z! }
k<xiP@b{y }
4{Vw30DZ }
,t4g^67R{ else if((lParam&0xc000ffff)==1){ //Key down
Sri,sZv switch(wParam)
7/.- dfEK {
<<@vy{*Hg case VK_MENU:
eMPkk=V MaskBits|=ALTBIT;
gl/n*s#r_ break;
b?#k case VK_CONTROL:
S ^?&a5{o MaskBits|=CTRLBIT;
8y!d ^EQ break;
0*66m:C2 case VK_SHIFT:
KmoPFlw MaskBits|=SHIFTBIT;
Xg|_ break;
s2t'jIB default: //judge the key and send message
.6Swc? break;
&8R %W"<K }
g{&a|NU^ for(int index=0;index<MAX_KEY;index++)
H\tz"<*`` {
GdFTKOq if(hCallWnd[index]==NULL)
"]}+QK_ continue;
-ec~~95 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Las4ux[_ {
B;A^5~b SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
][8ZeM9&p bProcessed=TRUE;
=;.#Bds }
eW$G1h: }
X4emhB }
,Mf@I5? if(!bProcessed){
[gZd$9a for(int index=0;index<MAX_KEY;index++){
9Ny{2m=Ye if(hCallWnd[index]==NULL)
i]{M G'tg continue;
=/@c9QaVB if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
sidSY8j SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
ar.w'z }
7dl]f#uZU }
JV|GEn\@N }
^E&':6( return CallNextHookEx( hHook, nCode, wParam, lParam );
FHVZ/ e }
"R-1G/ yBKkx@o#z BOOL InitHotkey()
MIPmsEdBi {
"|{O%X if(hHook!=NULL){
pqPhtWi%PJ nHookCount++;
xXl^\?HC return TRUE;
k36%n
*4 }
>&h#t7< else
K29]B~0%E hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
4C2J yP3 if(hHook!=NULL)
^|DI9G(Bs nHookCount++;
($^XF: #5 return (hHook!=NULL);
RG=!,#X }
g+gHIb7{ BOOL UnInit()
(q+U5Ls6 {
0eY$K7
U if(nHookCount>1){
*V(TNLIh; nHookCount--;
LGq}wxq return TRUE;
EJ P##eGx }
olzP=08aaV BOOL unhooked = UnhookWindowsHookEx(hHook);
I^'kt[P'FZ if(unhooked==TRUE){
'ypJGm nHookCount=0;
SS@F:5), hHook=NULL;
4CO:*qG)o }
(9x8,f0z return unhooked;
CW>f; }
{.2A+JT, n|F$qV_p\ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
HqXaT6#/ {
b]hP;QK`U$ BOOL bAdded=FALSE;
2`,{IHu*! for(int index=0;index<MAX_KEY;index++){
0IoS|P}6a if(hCallWnd[index]==0){
IH?.s
k
hCallWnd[index]=hWnd;
_@0>yMZ^ HotKey[index]=cKey;
ou6|;*>d HotKeyMask[index]=cMask;
IbAGnl { bAdded=TRUE;
$-9m8}U(Y KeyCount++;
)`]w\s
# break;
UPgjf }
Riid,n }
IGs!SXclCs return bAdded;
C,:3z }
('!90 c,;-[sn BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
z-nhL= {
S5]rIcM BOOL bRemoved=FALSE;
.Rxz;-VA for(int index=0;index<MAX_KEY;index++){
FCU~*c8Cs if(hCallWnd[index]==hWnd){
dL5u-<y& if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
;1K[N0xE hCallWnd[index]=NULL;
'bj$Z M9 HotKey[index]=0;
OpmI" 4{+ HotKeyMask[index]=0;
X<J
NwjM% bRemoved=TRUE;
FQSepUl KeyCount--;
)y-y-B=+T break;
v0`E
lkaN }
hp6S *d
}
/m%Y.:g }
1cWUPVQ return bRemoved;
D 4^2F(YRX }
hh`7b ,+ 4 ?fcQd6-} void VerifyWindow()
5'gV_U {
4'bup h1( for(int i=0;i<MAX_KEY;i++){
\M1- if(hCallWnd
!=NULL){ 0 }jB/Z_T
if(!IsWindow(hCallWnd)){ DWZ!B7Ts
hCallWnd=NULL; q?'*T?|
HotKey=0; !Y/$I?13Z
HotKeyMask=0; !q!.OQ
KeyCount--; 1t/#ZT!X/
} O#fGHI<43[
} X2!vC!4P?L
} 5F$ elW
} \gy39xoW(
GQO}E@W6C
BOOL CHookApp::InitInstance() .0;Z:x_3
{ MHJH@$|]
AFX_MANAGE_STATE(AfxGetStaticModuleState()); JSQNx2VqQ
hins=AfxGetInstanceHandle(); [5^"U+`{x
InitHotkey(); ;_),?(
return CWinApp::InitInstance(); #:v}d+
} JX@/rXFY}
37Vs9w
int CHookApp::ExitInstance() `~QS3zq
{ PvX>+y5
VerifyWindow(); sF}T9Ue
UnInit(); _M=
\s>;G
return CWinApp::ExitInstance(); dX-Xzg
} 82Dw,Cn
%JmSCjt`G
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file z/aZD\[_
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) !_)*L+7f_
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ n#,|C`2r
#if _MSC_VER > 1000 1foy.3g-
#pragma once .<j\"X(
#endif // _MSC_VER > 1000 x\!Q[
b&X- &F
class CCaptureDlg : public CDialog /<)A!Nn+F
{ `WSm/4m
// Construction |13UJ
vR
public: @#$5_uU8\(
BOOL bTray; a,IE;5kG
BOOL bRegistered; uFNVV;~RFI
BOOL RegisterHotkey(); gtWJR
UCHAR cKey; 3G|n`dj
UCHAR cMask; GV'Y'
void DeleteIcon(); vK
z/-9im
void AddIcon(); mnswGvY
UINT nCount; ,cD(s(6+
void SaveBmp(); > f,G3Ay
CCaptureDlg(CWnd* pParent = NULL); // standard constructor =m6;]16D
// Dialog Data z6#~B&