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:
G/(*foT8SE
50,Y 一、实现方法
{MxnIg7' :'Xr/| 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:
S.hC$0vrj <I1y #pragma data_seg("shareddata")
n^Vxi;F HHOOK hHook =NULL; //钩子句柄
ymkR! UINT nHookCount =0; //挂接的程序数目
o8tS static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
0[9I0YBJ static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
Mr.JLW static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
L$}g3{ static int KeyCount =0;
PGY9*0n static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
}$:#+
(17 #pragma data_seg()
u<kD} 9v$qrM`8 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。
<soj&f+ PI63RH8e 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:
H
pFb{
0Ve%.k BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
MHl^/e@ cKey,UCHAR cMask)
eE9|F/-L {
N5KEa]k1nw BOOL bAdded=FALSE;
-5xCQJ[ for(int index=0;index<MAX_KEY;index++){
xD0NZ~w% if(hCallWnd[index]==0){
H/`G hCallWnd[index]=hWnd;
a[ i>;0 HotKey[index]=cKey;
Xl?YBZ} HotKeyMask[index]=cMask;
Y-]YDXrPQ bAdded=TRUE;
e`AUYli" KeyCount++;
fkG##! break;
4,zvFH*AH }
}!=U^A) }
97 S? ;T return bAdded;
C#$6O8O }
P\T| [%E' //删除热键
5&*zY)UL BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
;Z4o{(/zU {
AWL[zixR BOOL bRemoved=FALSE;
~v\hIm3=m for(int index=0;index<MAX_KEY;index++){
s ^3[W0hL if(hCallWnd[index]==hWnd){
oXbI5XY)wb if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
3G.r- hCallWnd[index]=NULL;
1 KB7yG-#6 HotKey[index]=0;
#B}Qt5w HotKeyMask[index]=0;
Jh^8xI,`C bRemoved=TRUE;
[-]A^?yBM KeyCount--;
_25d%Ne0 break;
pI5_Hg }
hb<k]-'! }
Pxk0(oBX }
*`1bc'umM; return bRemoved;
9t}J|09i }
A!4VjE> *;P2+cE>H3 /.2 qWQH DLL中的钩子函数如下:
9fMSAB+c% .?Auh2nr LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Q]T BQ& {
qg)qjBQwA BOOL bProcessed=FALSE;
K9*IA@xL if(HC_ACTION==nCode)
u{P~zyx {
,02w@we5 if((lParam&0xc0000000)==0xc0000000){// 有键松开
fa yKM switch(wParam)
[G=:?J,P {
5y}BCY2=/ case VK_MENU:
KqK9X MaskBits&=~ALTBIT;
W\NG>t break;
hbH#Co~o4# case VK_CONTROL:
gg(k7e MaskBits&=~CTRLBIT;
(FG^UA#' break;
:Dj#VN case VK_SHIFT:
;le0QA
Pf MaskBits&=~SHIFTBIT;
o~k;D{Snr break;
vS#{-X default: //judge the key and send message
@ge
LW! break;
]/[0O+B? }
{!y<<u1 for(int index=0;index<MAX_KEY;index++){
Tm\OYYyk if(hCallWnd[index]==NULL)
"]UIz_^'`U continue;
]\`w1'* if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
aH {
kJ__:rS(T_ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
hm6pxFkX_ bProcessed=TRUE;
'mUI-1GkT }
4@mso+tk }
/L$NE$D} " }
r*]uR /Z$ else if((lParam&0xc000ffff)==1){ //有键按下
8
#Fh> switch(wParam)
vU{jda$$# {
_6LH"o3 case VK_MENU:
d
"B5==0I MaskBits|=ALTBIT;
La]4/=a break;
z
7@ 'CJ case VK_CONTROL:
q}e]*]dJZ MaskBits|=CTRLBIT;
+xq=<jy break;
9GE]<v,_[ case VK_SHIFT:
d9|T=R MaskBits|=SHIFTBIT;
ve~C`2=; break;
8lpzSJP4k default: //judge the key and send message
qJURPK break;
v?}pi }
}|,EU!nDi for(int index=0;index<MAX_KEY;index++){
6$DG.p if(hCallWnd[index]==NULL)
9j2\y=<& continue;
_\!0t if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
'(XW$D {
!YIb SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
5c)<'EP bProcessed=TRUE;
YMK>+y[+4 }
sjcQaF`= }
OSj%1KL }
m3B\)2B if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
h)P]gT0f/ for(int index=0;index<MAX_KEY;index++){
v/x*]c!"` if(hCallWnd[index]==NULL)
zaBG= continue;
^ISQ{M#_ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
_Po#ZGm~ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Z<I[vp6{ //lParam的意义可看MSDN中WM_KEYDOWN部分
Q+lbN }
;NBT 4 }
7fUi?41XA }
I IYL A( return CallNextHookEx( hHook, nCode, wParam, lParam );
AsD1-$ }
$=lJG(2% "`[ $&:~ 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
Ae.]F)w_\ 0T=jR{j!o BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
(%.</|u BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
EtJD'& F-$Kv-f 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:
}~V,_Fv Xa>}4j. LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
|fx#KNPf] {
f7S^yA[[ if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
L+u OBW_ {
-GK 'V //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
5vYsA1Z SaveBmp();
3/:LYvM< return FALSE;
>d'EInSF }
qq/_yt …… //其它处理及默认处理
`9:v*KuM#R }
xTGP cK/PQsMP G;Us-IRZ 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。
1O|RIv7F[/ n|J.)E. 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。
.\)--+( B{^`8Htrn 二、编程步骤
Gi;9 S RsR] T]4 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";
7L1\1E:! gW/QFZjY 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
2Qw)-EB v]l&dgoT 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;
\l>qY(gu %}\ vW 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;
K90D1sD {jrZ?e-q 5、 添加代码,编译运行程序。
IruyE(;HS G3oxa/mO 三、程序代码
:~-)Sm+^ VyRW ' ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
dE+CIjW5 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
9UB??049z #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
2&suo!ig #if _MSC_VER > 1000
{_": /A #pragma once
P*}9,VoY #endif // _MSC_VER > 1000
u=1B^V,6V #ifndef __AFXWIN_H__
2LtU;}7s #error include 'stdafx.h' before including this file for PCH
{K< ~
vj; #endif
Hf!9`R[ #include "resource.h" // main symbols
b,=,px class CHookApp : public CWinApp
iXt4|0 {
xU#]w6 public:
z<FV1niE CHookApp();
^)(G(=-Rf // Overrides
u Eu6f // ClassWizard generated virtual function overrides
n$nne6|O //{{AFX_VIRTUAL(CHookApp)
TJeou#=/ public:
H9.oVF^~ virtual BOOL InitInstance();
aE%eJ)+K virtual int ExitInstance();
tU8g(ep,o //}}AFX_VIRTUAL
!E4E' I=]N //{{AFX_MSG(CHookApp)
Nck!z8 // NOTE - the ClassWizard will add and remove member functions here.
c_R)P,P // DO NOT EDIT what you see in these blocks of generated code !
6z1aG9G //}}AFX_MSG
#nxER DECLARE_MESSAGE_MAP()
U`?zC~ };
o'9OPoof:. LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
m$j
n5: BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
eA3`]XP.`b BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
5d)'`hACe BOOL InitHotkey();
;5,`Jpca BOOL UnInit();
>OF:"_fh #endif
wghFGHgw NN31?wt //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Dwm@E\^ihm #include "stdafx.h"
WO.}DUfG+ #include "hook.h"
'YBLU )v[ #include <windowsx.h>
~}hba3&b;# #ifdef _DEBUG
~{52JeUc P #define new DEBUG_NEW
!gD 3CA #undef THIS_FILE
'8]|E
static char THIS_FILE[] = __FILE__;
&!H~bzg #endif
g~bf! #define MAX_KEY 100
BH.:_Qrbh[ #define CTRLBIT 0x04
I,?Fqg'sq #define ALTBIT 0x02
9n06n$F #define SHIFTBIT 0x01
P wt ?9I #pragma data_seg("shareddata")
[)C)p*!Y) HHOOK hHook =NULL;
c,b`N0dOKL UINT nHookCount =0;
c,g]0S?gu static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
,3fuX~g static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
UKt/0Ze static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
F^/~@^{P static int KeyCount =0;
1t~S3Q||>] static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
o|b[(t$;O #pragma data_seg()
"@UU[o HINSTANCE hins;
(ffOu#RQ3 void VerifyWindow();
9RCB$Ka6X BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
q?e16M //{{AFX_MSG_MAP(CHookApp)
/j=DC9_ // NOTE - the ClassWizard will add and remove mapping macros here.
,}xpYq_/ // DO NOT EDIT what you see in these blocks of generated code!
f 4
Sw,A //}}AFX_MSG_MAP
1FXzAc(c! END_MESSAGE_MAP()
XcJ'm{=
,6cbD CHookApp::CHookApp()
J
pCZq
# {
KxgR5#:i" // TODO: add construction code here,
OuYE-x2]x" // Place all significant initialization in InitInstance
%WJ\'@O\ }
pw(U< ) \'}/&PCkr CHookApp theApp;
jL>I5f LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
N9>'/jgZX {
sqMNon`5 BOOL bProcessed=FALSE;
?,+C!R? if(HC_ACTION==nCode)
0pZ.; /<{ {
s)`1Rf if((lParam&0xc0000000)==0xc0000000){// Key up
g4.'T51 switch(wParam)
{Q#Fen
;y| {
iuH8g case VK_MENU:
qxg7cj2 MaskBits&=~ALTBIT;
7 ~% break;
Uy_}@50"l case VK_CONTROL:
I;kUG_c(4 MaskBits&=~CTRLBIT;
P?3YHa^up break;
V5(tf' case VK_SHIFT:
5~kW-x MaskBits&=~SHIFTBIT;
cx1WGbZ break;
D x>1y default: //judge the key and send message
q~:'R break;
mBD!:V' }
y(wqcDok|n for(int index=0;index<MAX_KEY;index++){
6qHvq
A, if(hCallWnd[index]==NULL)
"0!eb3n continue;
|({UV-` if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
b;~EJ {
sg9x?Bx9 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
yv#c=v| bProcessed=TRUE;
J _[e9 }
R"\ub"] }
C&d"#I }
B'lxlYV1 else if((lParam&0xc000ffff)==1){ //Key down
.9[8H:Fe switch(wParam)
xTksF?u) {
t3yQ/ case VK_MENU:
8wH41v67F MaskBits|=ALTBIT;
zDGg\cPj9 break;
k_|v)\4B case VK_CONTROL:
wr;|\<c MaskBits|=CTRLBIT;
8n. "5,P break;
Ep,0Z*j case VK_SHIFT:
5LhJ8$W MaskBits|=SHIFTBIT;
x":Bw;~ break;
=J[[>H'<d default: //judge the key and send message
GqK&'c break;
G,mH!lSm, }
;5JIY7t for(int index=0;index<MAX_KEY;index++)
}TAGr 0 {
)2^/?jK if(hCallWnd[index]==NULL)
8ZDqqz^C0 continue;
0u&?Zy9& if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
uYFcq {
T0]%(F/8 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
]`i@~Z h\ bProcessed=TRUE;
2'UFHiK }
n\8[G[M }
n[cyK$" }
#&`WMLl+8 if(!bProcessed){
&Ow?Hd0 for(int index=0;index<MAX_KEY;index++){
,j(p}t if(hCallWnd[index]==NULL)
luxKgcU continue;
&L~31Ayj& if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
)(|0KarF SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
/NN[gz }
,h(f\h(9 }
JXy667_ }
#3:'lGBIK return CallNextHookEx( hHook, nCode, wParam, lParam );
39a]B`y }
ptc H>wM! Rp%\`'+Xz BOOL InitHotkey()
C4SD {
as\K(c9 if(hHook!=NULL){
J ]l@ r nHookCount++;
51;%\@= return TRUE;
[k&s!Qp }
id[>!fQ=Y else
&t%&l0 hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
J-%PyvK$? if(hHook!=NULL)
VOF:+o@. nHookCount++;
YQ8x6AJ return (hHook!=NULL);
(!&O4C5 }
XX5(/# BOOL UnInit()
+n.j.JP"X {
4[V6so 0 if(nHookCount>1){
*d,n2a#n5 nHookCount--;
ADl>~3b return TRUE;
F~@1n,[ }
6x3Ew2 BOOL unhooked = UnhookWindowsHookEx(hHook);
OD@A+" if(unhooked==TRUE){
O@(.ei*HJ! nHookCount=0;
}${ZI hHook=NULL;
ALt";8Oa }
~\s &]L return unhooked;
.2 SIU4[P }
XJ1nhE [j+0EVwB BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
+so o2cb {
y7G|P~td BOOL bAdded=FALSE;
]O(HZD% for(int index=0;index<MAX_KEY;index++){
S?z j&XY3 if(hCallWnd[index]==0){
\iLd6Qo_aq hCallWnd[index]=hWnd;
`kT$Gx4x HotKey[index]=cKey;
9 0(oV& HotKeyMask[index]=cMask;
_<~Vxz9 bAdded=TRUE;
4 }YT@={g} KeyCount++;
(pxz#B4 break;
&b]KMAo3 }
Z
7ZMu }
:V1ZeNw return bAdded;
0c;"bA0>Sx }
o!dkS/u-m =
Ow&UI BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
*l8vCa9Y {
[x()^{;2 BOOL bRemoved=FALSE;
3eDx@8N
} for(int index=0;index<MAX_KEY;index++){
?*5l}y= if(hCallWnd[index]==hWnd){
/n}V7 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
$gtT5{"PN( hCallWnd[index]=NULL;
eDZ3SIZ HotKey[index]=0;
X1~A "sW[ HotKeyMask[index]=0;
x=r6vOj bRemoved=TRUE;
}Mlz\'{ KeyCount--;
]mU*Y:< break;
L=Jk"qWV0 }
(C[S?@S }
,&l