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:
WelB"L
4W<8u( 一、实现方法
7OD2/{]5 &?*H`5#?G 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:
i#I7ncX hQ}y(2A.XI #pragma data_seg("shareddata")
J\E?rT HHOOK hHook =NULL; //钩子句柄
^wD@)Dz UINT nHookCount =0; //挂接的程序数目
RG6U~o1 static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
M.K%;j` static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
;Dp<|n static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
] p*Fq^ static int KeyCount =0;
8Z>=sUMQ static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
"b[w%KYyl #pragma data_seg()
F.iJz4ya_ t_hr$ { 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。
{-l:F2i 3M"eAK([ 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:
rLE5fl5W 5@^['S4%8* BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
_n+
5{\z cKey,UCHAR cMask)
$q g/8G {
%b>Ee>rdD BOOL bAdded=FALSE;
IN?rPdY for(int index=0;index<MAX_KEY;index++){
ys9'1+9 if(hCallWnd[index]==0){
n{=N f|= hCallWnd[index]=hWnd;
-d*je{c| HotKey[index]=cKey;
<xh";seL HotKeyMask[index]=cMask;
78kT}kgW bAdded=TRUE;
-DWnDku8= KeyCount++;
CD pLV: break;
k3UKGP1 }
zhVkn]z~* }
Qsg([K return bAdded;
j7qGZ"8ak }
N*'d]P2P`J //删除热键
@i(;}rx BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
{7^D!lis {
~IQw?a.E BOOL bRemoved=FALSE;
ZDr&Alp)o for(int index=0;index<MAX_KEY;index++){
K9c5HuGy if(hCallWnd[index]==hWnd){
u&r+ylbsI if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
6tN!] hCallWnd[index]=NULL;
"f4atuuXa HotKey[index]=0;
(tQ0-=z HotKeyMask[index]=0;
vJsx_i\i bRemoved=TRUE;
aH*5(E] KeyCount--;
1? Im" break;
-op(26:W< }
RP%7M8V){B }
THmmf_w@ }
-GT&46hX return bRemoved;
sW0<f&3 }
VH6J
@m jbTsrj"g OFn#C! DLL中的钩子函数如下:
Bn5$TiTcl J'@`+veE LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
a1gaB:w5n {
,XYtoZa BOOL bProcessed=FALSE;
2!";?E if(HC_ACTION==nCode)
"U*6?]f {
lH"4"r if((lParam&0xc0000000)==0xc0000000){// 有键松开
V]P%@<C switch(wParam)
'<Jqp7$dL {
1(jDBP!8 case VK_MENU:
c63yJqiW MaskBits&=~ALTBIT;
%<@x(q break;
(}MN16! case VK_CONTROL:
T*rx5*:o MaskBits&=~CTRLBIT;
%Mr^~7nN break;
!@9G9<NK case VK_SHIFT:
,Kwtp)EX MaskBits&=~SHIFTBIT;
=v7%IRP5 break;
L]{1@~E:q default: //judge the key and send message
M`tNYs]V break;
4(TR'_X( }
rfYFS96 for(int index=0;index<MAX_KEY;index++){
&nfGRb if(hCallWnd[index]==NULL)
2)(ynrCe continue;
Y *n[*N if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
+K7oyZg {
52q<|MW% SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
D0LoT?$N bProcessed=TRUE;
tlcNGPa }
eY8rm }
d< b ,]. }
*/y (~O6 else if((lParam&0xc000ffff)==1){ //有键按下
4x2,X`pe3 switch(wParam)
P:fcbfH+ {
E@7);i5K case VK_MENU:
hv#|dI=kZR MaskBits|=ALTBIT;
HB,
k}Q break;
YOQ>A*@4 case VK_CONTROL:
s> JWNP MaskBits|=CTRLBIT;
O^KIB%}fu break;
;lc/FV[/ case VK_SHIFT:
s}bv
o MaskBits|=SHIFTBIT;
,O`~ D~$ break;
c&I"&oZ@& default: //judge the key and send message
rA[wC%% break;
LW*v/`@ }
#T$yQ;eQ for(int index=0;index<MAX_KEY;index++){
W \XLf,_+ if(hCallWnd[index]==NULL)
eWWfUNBSLX continue;
R>R8LIZZc if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
z65Q"A {
-;j
'=? SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
69$gPY'3 bProcessed=TRUE;
=p>IP"HJ }
`}S;_g! }
h Nx#x }
MP$9W) if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
PAS0 D
# for(int index=0;index<MAX_KEY;index++){
f8S! FGiNc if(hCallWnd[index]==NULL)
nj6|WJ continue;
-d_7 q if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
@ ('/NjTZ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
# "!q_@b,D //lParam的意义可看MSDN中WM_KEYDOWN部分
M6XpauR- }
d'k99(vy }
D2]i*gs }
AI#.G7'O return CallNextHookEx( hHook, nCode, wParam, lParam );
D] +]Br8 }
A^vvw~!d 0F9p'_C 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
\^x`GsVy =:_DXGW2H BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
U o[\1) BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
*u ]aWx pB'{_{8aA 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
'f-8P k nljc^ LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
85qD~o?O {
Y+ !z]S/x if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
>>%E?'9A {
{'z( //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
)jGB[s";)y SaveBmp();
3GPGwzX
| return FALSE;
jJyS^*.X }
s y>}2orj~ …… //其它处理及默认处理
]h%~'8g, }
_B7+n"t\r b=XXp`h~a ?,w9e| 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
JKA%$l0 J~|:Q.Rt` 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。
c\OLf_Uf Ogu";p( 二、编程步骤
B{!*OC{l W~j>&PK,? 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";
pvhN.z '$5Qdaj 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
`J%35 AmB*4p5b 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
WSbD."p< g17 fge6% 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
O96%U$W "f:_(np, 5、 添加代码,编译运行程序。
Ou{VDE wL[{6wL 三、程序代码
m1Xc3=Y -{ES 36 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
2]cU:j6G #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
J+m1d\lBu #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
b}!T!IP} #if _MSC_VER > 1000
PO*0jO;% #pragma once
" TC:O^X #endif // _MSC_VER > 1000
88Vl1d&b #ifndef __AFXWIN_H__
I ;F\'P)e #error include 'stdafx.h' before including this file for PCH
s[#_sR`y #endif
P
c'\ #include "resource.h" // main symbols
La$?/\Dv) class CHookApp : public CWinApp
(BGflb {
B-h@\y public:
B^Hhrz! CHookApp();
xu.TS // Overrides
O% 8>siU // ClassWizard generated virtual function overrides
Lum5Va%0 //{{AFX_VIRTUAL(CHookApp)
`5SQ4 public:
HL%|DCo virtual BOOL InitInstance();
,L\>mGw virtual int ExitInstance();
up2wkc8 //}}AFX_VIRTUAL
|!L0X@> //{{AFX_MSG(CHookApp)
O?0`QMY // NOTE - the ClassWizard will add and remove member functions here.
q
+!i6!6r // DO NOT EDIT what you see in these blocks of generated code !
c~u91h? //}}AFX_MSG
!M}ZK( DECLARE_MESSAGE_MAP()
YL/B7^fd8 };
Hb\['VhzM LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
b1EY6'R2 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
A`*Sx"~jdx BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
:@~mN7O* BOOL InitHotkey();
byPqPSY BOOL UnInit();
\?vn0;R4 #endif
P52qt N< #9t3 <H[ //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Jk57| )/ #include "stdafx.h"
|Q$Dj!!1P #include "hook.h"
bzh: #include <windowsx.h>
)!Zm*( #ifdef _DEBUG
lsU`~3nr #define new DEBUG_NEW
{ a_&L #undef THIS_FILE
i93^E~q] static char THIS_FILE[] = __FILE__;
|eqp3@Y1E #endif
|y4j:`@. #define MAX_KEY 100
krRnE7\m #define CTRLBIT 0x04
, 8o
Y(h #define ALTBIT 0x02
IU\h,Ug #define SHIFTBIT 0x01
C0W-}H #pragma data_seg("shareddata")
E.G]T#wt0 HHOOK hHook =NULL;
|a=7P UINT nHookCount =0;
{T 3~js static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
7GRPPh<4 static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
a}[rk*QmZ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
M/kBAxNIC| static int KeyCount =0;
iUlSRfrC$# static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
q^6l`JJ #pragma data_seg()
8|tnhA]~ HINSTANCE hins;
uP.dCs9- void VerifyWindow();
bycnh BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
Zou;o9Ww //{{AFX_MSG_MAP(CHookApp)
a~Yq0 d?`D // NOTE - the ClassWizard will add and remove mapping macros here.
%v[KLMo'( // DO NOT EDIT what you see in these blocks of generated code!
9>=S@hVMd //}}AFX_MSG_MAP
bT`et*] END_MESSAGE_MAP()
0qL.Rnt e?:1wU CHookApp::CHookApp()
V0xO:7G^ {
EAoq2_(`a // TODO: add construction code here,
j:U6q,f] // Place all significant initialization in InitInstance
=nv/
r }
\pXo~;E\ *mn"GK6 CHookApp theApp;
7=a
e^GKo LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
_% i!LyG {
E+J +fi BOOL bProcessed=FALSE;
(?ZS9&y} if(HC_ACTION==nCode)
Tj6kCB {
p5J!j I= if((lParam&0xc0000000)==0xc0000000){// Key up
h]&o)%{4 switch(wParam)
_7
^:1i~:. {
<(l`zLf4p case VK_MENU:
YwZ]J MaskBits&=~ALTBIT;
[= Xb*~ break;
IGo+O*dMw case VK_CONTROL:
Jt3*(+J>/ MaskBits&=~CTRLBIT;
8d(l)[GZt break;
Dlz1"|SF case VK_SHIFT:
vJe c+a MaskBits&=~SHIFTBIT;
gUme({h&| break;
oiQ:&$y default: //judge the key and send message
'ql<R0g break;
XW:%YTv }
BOv ^L?)*Z for(int index=0;index<MAX_KEY;index++){
WQMoAPfqL if(hCallWnd[index]==NULL)
<4TF ]5 continue;
b?:?" if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
G-'CjiMu {
izR#XeBm SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
nI/kX^Pd bProcessed=TRUE;
( +(bw4V/ }
zEDN^K ' }
w@H@[x }
p,14'HS%@ else if((lParam&0xc000ffff)==1){ //Key down
I7W?}bR*6 switch(wParam)
m,&2s-v {
1^2]~R9,9 case VK_MENU:
J7@Q;gcl: MaskBits|=ALTBIT;
d3NER} f4V break;
%2'Y@AX` case VK_CONTROL:
Qe`Nb4xf MaskBits|=CTRLBIT;
b^"mQ break;
qyjVB/ko case VK_SHIFT:
=]o2{d MaskBits|=SHIFTBIT;
~Xc1y!"9* break;
j|@8VxZ default: //judge the key and send message
6O" y break;
: :928y }
(&M,rW~Qxs for(int index=0;index<MAX_KEY;index++)
g`4WisL1n {
d w'P =8d if(hCallWnd[index]==NULL)
\_7'f continue;
'
?a d if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
\vE-;, {
v!AfIcEV SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
Yn>FSq^Wp- bProcessed=TRUE;
u]P9ip"Z }
$?On,U }
y:k7eE" }
S";}gw?r6 if(!bProcessed){
Eo@rrM: for(int index=0;index<MAX_KEY;index++){
n!U1cB{ if(hCallWnd[index]==NULL)
+ZkJ{r0,( continue;
IiV]lxiE] if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
QT4vjz+| SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
WLH ;{ }
&:~9'-O }
/*Gbl }
z6fY_LL return CallNextHookEx( hHook, nCode, wParam, lParam );
yF-`f
_ }
3dgPP@7d$ KON^ BOOL InitHotkey()
<3x:nH @ {
a..LbQQ if(hHook!=NULL){
KBA&s nHookCount++;
Z>*a:| return TRUE;
L%Ms?`i, }
sTvw@o* else
U-D00l7C hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
U"Y/PBs, if(hHook!=NULL)
'tt4"z2 nHookCount++;
zL3I!& z2 return (hHook!=NULL);
TRr%]qd{Hr }
e@PY(#ru BOOL UnInit()
u ^M'[<{ {
7gREcL2 if(nHookCount>1){
@B!gxW\C nHookCount--;
>^g\s]c[ return TRUE;
.-1'#Z1T }
oAvLSFn BOOL unhooked = UnhookWindowsHookEx(hHook);
eTI?Mu>C if(unhooked==TRUE){
Ac\e>N nHookCount=0;
r+tHVh hHook=NULL;
i0~Af`v }
$p*.[) return unhooked;
`2y?(BJp }
~6{U^3 0Kg?X BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
6Q_ZP#oAV {
o'? WWJK6w BOOL bAdded=FALSE;
)ib$*dmUP for(int index=0;index<MAX_KEY;index++){
QFFFxaeJg if(hCallWnd[index]==0){
^ZFK:|Ju hCallWnd[index]=hWnd;
f,Am;:\ | HotKey[index]=cKey;
s<5P sR HotKeyMask[index]=cMask;
ViU5l*n; bAdded=TRUE;
bpa'`sf KeyCount++;
6cOlY=
bn break;
m14'u GC }
<VhD>4f{] }
wWM[Hus return bAdded;
/$9We8 }
W*2P+H% 'ZAIe7i& BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
T>,[V: {
S$46YQ BOOL bRemoved=FALSE;
PgsG*5WQ for(int index=0;index<MAX_KEY;index++){
2_TFc2d if(hCallWnd[index]==hWnd){
k&npC8oA if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
3 ;AJp_; hCallWnd[index]=NULL;
I~nz~U:ak HotKey[index]=0;
Lzx2An@R HotKeyMask[index]=0;
T&j:gg bRemoved=TRUE;
YR[I,j KeyCount--;
HrUE?Sq break;
(IIZ vCek }
&g]s@S|% }
HE0m# }
I/u>Gt return bRemoved;
B?4Iu)bCxI }
5>hXqNjP2 @QE&D+NS void VerifyWindow()
VFKFO9 {
D58RHgY[ for(int i=0;i<MAX_KEY;i++){
6_K7!?YG7 if(hCallWnd
!=NULL){ AB<%GzW0(
if(!IsWindow(hCallWnd)){ NHe[,nIV
hCallWnd=NULL; U#{(*)qr
HotKey=0; _/YM@%d
HotKeyMask=0; xl9S=^`=
KeyCount--; tjQ6[`
} dV
/Es
} .UvDew/Y
} o
^ 08<
} fh`}~ aQ
z
G`|)
BOOL CHookApp::InitInstance() V`G^Jyj
{ '=J|IN7WT
AFX_MANAGE_STATE(AfxGetStaticModuleState()); k7]4TIUD*
hins=AfxGetInstanceHandle(); 7/iN`3Bz
InitHotkey(); Yy,XKIqU
return CWinApp::InitInstance(); Bq,MTzxD
} "*:?m{w5
h<qi[d4X
int CHookApp::ExitInstance() kV4L4yE
{ +}eK8>2
VerifyWindow(); c= aZ[
UnInit(); E&)o.l<h|
return CWinApp::ExitInstance(); m ;wj|@cF
} %CqG/ol
=Z..&H5i
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file x@D>JG
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) "BIhd*K[~
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ ]`|;ZQiD
#if _MSC_VER > 1000 }0]iS8*tL
#pragma once PGuPw'2;[
#endif // _MSC_VER > 1000 X_)x Fg'k
>)k[085t
class CCaptureDlg : public CDialog RFq=`/>dG
{ iO$ ?No
// Construction [7 t
public: C8=r sh
BOOL bTray; Ox@$ }
BOOL bRegistered; !E,|EdIr
BOOL RegisterHotkey(); 7/K'nA
UCHAR cKey; w}8=sw
UCHAR cMask; l9n$cv^
void DeleteIcon(); F2Gg_u@7M
void AddIcon(); N|8^S
UINT nCount; ),$^h7[n
void SaveBmp(); !j3Xzn9
CCaptureDlg(CWnd* pParent = NULL); // standard constructor )JU`Z@?8
// Dialog Data h!tg+9%
//{{AFX_DATA(CCaptureDlg) "![KQ
enum { IDD = IDD_CAPTURE_DIALOG }; uE>m3Y(aP
CComboBox m_Key; TCi0]Y~a
BOOL m_bControl; >y$*|V}k
BOOL m_bAlt; =E:sEw2j
BOOL m_bShift; 4 b}'W}
CString m_Path; IDdu2HNu
CString m_Number; [Scao $
//}}AFX_DATA O%<+&