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:
EXo"F*gW
x.}iSE{ 一、实现方法
P PmE.%_ {:!*1L 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:
_d,_&7 nww,y #pragma data_seg("shareddata")
y/
vE HHOOK hHook =NULL; //钩子句柄
hoPCbjkov UINT nHookCount =0; //挂接的程序数目
hfVJg7- static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
9D-PmSnv static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
_>*TPlB static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
9'T
nR[> static int KeyCount =0;
-R|v&h%T static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
j].XVn, #pragma data_seg()
VYik#n>|Gp %~G)xK?W* 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。
Y+lZT4w _?mu2!X 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+ydVj(Op wR\%tumk BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
.y|* cKey,UCHAR cMask)
/2WGo- {
b$%W<D BOOL bAdded=FALSE;
ig jr=e for(int index=0;index<MAX_KEY;index++){
w8$8P if(hCallWnd[index]==0){
qK,rT*5= hCallWnd[index]=hWnd;
zGA1 HotKey[index]=cKey;
Np+<)q2 HotKeyMask[index]=cMask;
{0QNqjue bAdded=TRUE;
>pUR>?t" KeyCount++;
CKy' 8I9 break;
=`99ez+y }
FL9Dz4 }
O_*%_S}F& return bAdded;
3Vs8"BFjz }
0.=dOz r //删除热键
M;-PrJdyt BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
7S}NV7 {
i=nd][1n BOOL bRemoved=FALSE;
4Zo.c*
BZ for(int index=0;index<MAX_KEY;index++){
V*}ft@GPD if(hCallWnd[index]==hWnd){
4ba[*R2 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
,F!zZNW9 hCallWnd[index]=NULL;
E WrIDZi HotKey[index]=0;
xN'$Yh
HotKeyMask[index]=0;
3c}@_Yn bRemoved=TRUE;
f;x0Ho5C2 KeyCount--;
3fM8W>
*7 break;
Iw~R@, }
WBK6Ug }
BF
b<"!Y }
T]HeS( return bRemoved;
"A6m-xE~ }
QVJq% P ,` 6O{Z~ oIrO%v:'! DLL中的钩子函数如下:
lK
5@qG# SYkwM6 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
s'b 4Me {
Y 3h`uLQ BOOL bProcessed=FALSE;
FC@h6\+a if(HC_ACTION==nCode)
?(0=+o(` {
C.].HQ if((lParam&0xc0000000)==0xc0000000){// 有键松开
k{d] switch(wParam)
2RG6m=Y8y {
~G,_4}#"pM case VK_MENU:
-n FKP&P MaskBits&=~ALTBIT;
9kHVWDf break;
vJ9I z case VK_CONTROL:
^m~&2l\N= MaskBits&=~CTRLBIT;
d<K2
\:P{} break;
r2yJ{j&s case VK_SHIFT:
( RO-~- MaskBits&=~SHIFTBIT;
70Jx[3vr break;
& %A&&XT9 default: //judge the key and send message
!mHMFwvS break;
GZH{"_$ }
`Y O(C<r- for(int index=0;index<MAX_KEY;index++){
Pm&h v*D if(hCallWnd[index]==NULL)
& 6'Rc#\P continue;
sPX&XqWx if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
FJ,"a%m/Q {
}C4wED. SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
u}3D'h bProcessed=TRUE;
Znr@-=xZO* }
YLJ^R$pi }
ckGmwYP9 }
v;soJlxF~ else if((lParam&0xc000ffff)==1){ //有键按下
hh8Grl; switch(wParam)
%5RR<[_/; {
3 {$vN). case VK_MENU:
>Q$ph= MaskBits|=ALTBIT;
|;:g7eb break;
dq,j?~ _} case VK_CONTROL:
Yw] 7@ MaskBits|=CTRLBIT;
v{d$DZUs break;
J-#V_TzJ? case VK_SHIFT:
NNt
n MaskBits|=SHIFTBIT;
&hEn3u break;
&S,_Z/BS; default: //judge the key and send message
"!+gA& break;
<Pzy'9 }
Lq|>n[KY for(int index=0;index<MAX_KEY;index++){
J2<kOXXJ9 if(hCallWnd[index]==NULL)
ijsoY\V50 continue;
IjGPiC if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
pHT]2e# {
B (Ps/ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
cbN;Kv?ak} bProcessed=TRUE;
m g,1*B' }
^/_Yk.w }
T/a=z }
4-~Z{#- if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
&rG B58 for(int index=0;index<MAX_KEY;index++){
KL9k9|!p if(hCallWnd[index]==NULL)
fIl;qGz85 continue;
WQ{[q" O if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
`78Bv>[A SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
z/u^ //lParam的意义可看MSDN中WM_KEYDOWN部分
8N%nG(
0 }
|BbzRis }
dvZH ~mF }
(:aU"5M return CallNextHookEx( hHook, nCode, wParam, lParam );
AtewC
Yo }
D|)a7_ OvAhp&k 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:
+$|fUn{ W:,Wex^9n BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
K>dB{w#gS BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
om`T/@_, jUE gu 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
ki?h7 !!A0K"h LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
#F`A(n {
t%;w<1E if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
d2V X\ {
R*:>h8 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
[% C,&h5 SaveBmp();
s bj/d~$N return FALSE;
H T|DT }
#8|LPfA …… //其它处理及默认处理
i|J%jA }
<XIIT-b[ qT48Y oQ 2$z8 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
)rq |t9kix MC* Hl`C 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
^cm]
[9 ZUHRATT- 二、编程步骤
7~SwNt, 0?<#! 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
z$e6T&u5B Pg%9hejf3 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
?3=G'Ip5n %WgN+A0 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;
2 %dL96 &}r"Z?f) 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;
fes s6=k b,Oh8O;> 5、 添加代码,编译运行程序。
.qgUD H5T_i$W 三、程序代码
G18w3BFx ]K"&Vd ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
O\6U2b~ #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
_dJ(h6%3 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
5J10S #if _MSC_VER > 1000
6RnzT d #pragma once
{drc}BL_ #endif // _MSC_VER > 1000
5~|{:29X #ifndef __AFXWIN_H__
Snx!^4+MF #error include 'stdafx.h' before including this file for PCH
aYWWln #endif
$VuXr=f} #include "resource.h" // main symbols
){*+s RBW class CHookApp : public CWinApp
"j@\a)a {
5&ku]l+ public:
K]hp-QK< CHookApp();
$"r9U|6kk // Overrides
c-sjYJXKM* // ClassWizard generated virtual function overrides
Q?#I{l)V( //{{AFX_VIRTUAL(CHookApp)
2;8m0+tl public:
`gX@b^ virtual BOOL InitInstance();
.UG`pRC virtual int ExitInstance();
?13qDD: //}}AFX_VIRTUAL
fSkDD>& //{{AFX_MSG(CHookApp)
|_V(^b} // NOTE - the ClassWizard will add and remove member functions here.
`POzwYh // DO NOT EDIT what you see in these blocks of generated code !
wI$a1H //}}AFX_MSG
{FNkPX DECLARE_MESSAGE_MAP()
?, S/>SP };
DN*5q9. LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
l3>S{ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
CMXF[X)% BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
AcC &Q:g BOOL InitHotkey();
yD7BZI
xW BOOL UnInit();
;-+q*@sa] #endif
or/gx 3 zx3gz7>k; //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
qN $t_ #include "stdafx.h"
0cd_l
2f#g #include "hook.h"
\D7bTn #include <windowsx.h>
qqrjI. #ifdef _DEBUG
V'Gal` #define new DEBUG_NEW
'X^auyL #undef THIS_FILE
Y`;}w}EcgR static char THIS_FILE[] = __FILE__;
F5h/> #endif
FSIiw#xzH #define MAX_KEY 100
5(3O/C{?~ #define CTRLBIT 0x04
"& ,ov# #define ALTBIT 0x02
fw%`[(hK #define SHIFTBIT 0x01
CSO'``16 #pragma data_seg("shareddata")
&{}Mds HHOOK hHook =NULL;
jJy:/!i UINT nHookCount =0;
EB~]6.1 static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
?sf<cFF static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
1E+12{~m"i static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
g!'R}y static int KeyCount =0;
gcJ!_KZK static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
$[ {5+ * #pragma data_seg()
g7 \= HINSTANCE hins;
mdj%zJ8/ void VerifyWindow();
`o[l%I\Q BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
W>K^55' //{{AFX_MSG_MAP(CHookApp)
$x0SWJ \G // NOTE - the ClassWizard will add and remove mapping macros here.
>STtX6h // DO NOT EDIT what you see in these blocks of generated code!
]A*}Dem*5 //}}AFX_MSG_MAP
Q7BbST+ END_MESSAGE_MAP()
fB+L%+mr8 y&/IJst&aq CHookApp::CHookApp()
C($l'jd& {
!"rPSGK* // TODO: add construction code here,
p4`1^}f&Ie // Place all significant initialization in InitInstance
o
NtFYY }
: T*Q2 #9vC]Gm CHookApp theApp;
Shm> r@C? LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
/^.|m3 {
(WM3(US| BOOL bProcessed=FALSE;
aurs~ if(HC_ACTION==nCode)
vgz`+Zj*S {
"y1Iu if((lParam&0xc0000000)==0xc0000000){// Key up
YR%iZ"`*+O switch(wParam)
NAbVH{*\U {
dbI>\khI case VK_MENU:
oQ!M+sRmF MaskBits&=~ALTBIT;
:E:e ^$p break;
T$4{fhV
\ case VK_CONTROL:
zWHq4@K MaskBits&=~CTRLBIT;
_?{7%(C break;
JJ?{V: case VK_SHIFT:
C?PQ>Q!f- MaskBits&=~SHIFTBIT;
Z_d"<k}I break;
"yWw3(V2> default: //judge the key and send message
uO?+vYAN break;
)!T~l(g }
NGx3f3 9 for(int index=0;index<MAX_KEY;index++){
6TtB3;5 if(hCallWnd[index]==NULL)
8nz({Mb9Z continue;
U{U"%XdO if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Q;M\fBQO}& {
?,} u6tH SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
TT$Ao bProcessed=TRUE;
FFHq':v }
:^;c(>u{ }
R.~[$G! }
D /eH~ else if((lParam&0xc000ffff)==1){ //Key down
9!FX*}dC switch(wParam)
jr6_|(0
i6 {
)vp0X\3q` case VK_MENU:
Dl,QCZeM MaskBits|=ALTBIT;
9&6j uL break;
c}(WniR-" case VK_CONTROL:
*@U{[J MaskBits|=CTRLBIT;
K,b
M9>} break;
3DU1c?M: case VK_SHIFT:
r*X,]\V0x MaskBits|=SHIFTBIT;
Z>[7#;; break;
&Y@i:O default: //judge the key and send message
}X(&QZ7i` break;
+mQ5\14# }
\2SbW7"/;P for(int index=0;index<MAX_KEY;index++)
m'4f'tbN {
)^2eC<t if(hCallWnd[index]==NULL)
qd`e:s*% continue;
>oh H4: if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
&w@]\7L,: {
Z8$}Rpo SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
ua\t5M5 bProcessed=TRUE;
kaG/8G( }
BZR{}Aj4pa }
^t>mdxuq }
LPk@t^[ if(!bProcessed){
l_B735 for(int index=0;index<MAX_KEY;index++){
Kxe\H'rR if(hCallWnd[index]==NULL)
G\.~/<Mg+ continue;
]9@:7d6 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Xn7G2Yp SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
C2
N+X ( }
c9(3z0!F? }
a#oROb-*~ }
Fr%# return CallNextHookEx( hHook, nCode, wParam, lParam );
rp Nb. }
.`or^`X3 4{VO:(geZ BOOL InitHotkey()
/y$Omc^ {
KA3U W if(hHook!=NULL){
d}
>Po%r: nHookCount++;
bIQ,=EA1
return TRUE;
q+P@2FL }
.)Tj}Im2p else
d{z[46> hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
VPLf( if(hHook!=NULL)
@]\fO)\f nHookCount++;
R@e'=z[%1 return (hHook!=NULL);
8K%N7RL| }
l|5 h BOOL UnInit()
m</m9h8 {
b@CB +8$ if(nHookCount>1){
+UzQJt/>> nHookCount--;
W4^L_p>Tm^ return TRUE;
;vn0%g }
kY0HP a BOOL unhooked = UnhookWindowsHookEx(hHook);
$|4@Zx4vf if(unhooked==TRUE){
[W[{
4 Xu nHookCount=0;
3JazQU hHook=NULL;
#3uv^m LGa }
d;i|s[6ds` return unhooked;
A5l Cc
b }
ts]e M1; FU`(mQ*Yd BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
| /.J{=E0K {
5Qgu:)} BOOL bAdded=FALSE;
AFLtgoXn: for(int index=0;index<MAX_KEY;index++){
?K1B^M=8 if(hCallWnd[index]==0){
dFg>uo hCallWnd[index]=hWnd;
tV}!_ HotKey[index]=cKey;
hfB$4s9 HotKeyMask[index]=cMask;
{Jr1K, bAdded=TRUE;
_nGx[1G( 5 KeyCount++;
qGk+4 yC break;
#2Rz=QI }
`/|
*u }
F.s$Y+c!6 return bAdded;
2.qPMqH }
H MOIUd yOM/UdWq BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
[8V;Q {
~ |G&cg BOOL bRemoved=FALSE;
lg%fjBY for(int index=0;index<MAX_KEY;index++){
Vax g if(hCallWnd[index]==hWnd){
!-I,Dh-A if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
4.A^5J'W hCallWnd[index]=NULL;
q^X7x_ HotKey[index]=0;
w,|@e_|J HotKeyMask[index]=0;
ns[/M~_r bRemoved=TRUE;
5eAZfe%H KeyCount--;
0KA*6]h t break;
SmXJQ@jN }
7?lz$.*Avp }
U~G7~L &m }
"8za'@D"f return bRemoved;
D%>Bj>xQD }
6)[moR{N1 bpu`'Vx void VerifyWindow()
Iu'9yb {
<,vIN,Kl8/ for(int i=0;i<MAX_KEY;i++){
f-U zFlU if(hCallWnd
!=NULL){ Ku5||u.F4*
if(!IsWindow(hCallWnd)){ X'A`"}=_
hCallWnd=NULL; lg^'/8^f
HotKey=0; r[9m-#)>
HotKeyMask=0; X4 !93
KeyCount--; EEe$A?a;
} DYX{v`>f^
} .ARYCTyG
} F`=p/IAJK
} iSfRJ:_&6
?<Qbp;WBo
BOOL CHookApp::InitInstance() m:BzIcW<\
{ W]4Z4&