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:
Qp%kX@Z'
Z'!jZF~4p 一、实现方法
]Kil/Y H6*F?a`)I 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:
;J2=6np }1epn#O_4 #pragma data_seg("shareddata")
-`#L rO;n HHOOK hHook =NULL; //钩子句柄
R (4 :_ xc UINT nHookCount =0; //挂接的程序数目
{Pu\KRU static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
N'|zPFkg static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
G8eAj%88 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
(;cbgHo%} static int KeyCount =0;
a\^DthZ!;| static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
fE7[Sk #pragma data_seg()
GT2;o ;V`~'357% 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。
C %y AMQ OfY>~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:
6-<,1Q'D Gz$DsaG BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
eH79,!=2 cKey,UCHAR cMask)
T3!l{vG
\O {
"l2_7ZXsPT BOOL bAdded=FALSE;
x@ (91f for(int index=0;index<MAX_KEY;index++){
@ttcFX1:W if(hCallWnd[index]==0){
5-aCNAF2 hCallWnd[index]=hWnd;
>:h
8T]F HotKey[index]=cKey;
rOH8W HotKeyMask[index]=cMask;
naM4X@jl bAdded=TRUE;
+g\u=&<6 KeyCount++;
a+,)rY9 break;
xlS
t }
~ia#=|1} }
980[]&( return bAdded;
$UO7AHk }
]-["sw //删除热键
v"=^?5B BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
3v5]L3 {
z2S53^C* BOOL bRemoved=FALSE;
\MX>= for(int index=0;index<MAX_KEY;index++){
HrWXPac
A if(hCallWnd[index]==hWnd){
3mpEF<z if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Fg`r:,(a hCallWnd[index]=NULL;
NCl$vc;, HotKey[index]=0;
19&!#z HotKeyMask[index]=0;
Dy0cA| E bRemoved=TRUE;
O. @_2 KeyCount--;
Vg&`f break;
]p@7[8} }
o+q4Vg9& }
;]+kC }
x1?p+ return bRemoved;
4|7L26,]5 }
Z'PL?;&+R lg;`I tX] (Q\QZu@ DLL中的钩子函数如下:
-9vAY+s. HFvhrG LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
nEyPNm) {
D("['`{ BOOL bProcessed=FALSE;
FHqa|4Ie if(HC_ACTION==nCode)
'+Ts IJh {
pA"pt~6 if((lParam&0xc0000000)==0xc0000000){// 有键松开
rh/3N8[6 switch(wParam)
XNd:x{ {
ayHI(4!$j case VK_MENU:
|]Pigi7y- MaskBits&=~ALTBIT;
#li;L break;
PBR+NHrZ case VK_CONTROL:
H Viu7kue` MaskBits&=~CTRLBIT;
1K4LEga` break;
x(}@se case VK_SHIFT:
E+UOuf*( MaskBits&=~SHIFTBIT;
3zMmpeq break;
6D_4o&N default: //judge the key and send message
24>{T5E break;
j?3J-}XC }
?^5W.`Y2i for(int index=0;index<MAX_KEY;index++){
ps_CQh0 if(hCallWnd[index]==NULL)
ib*$3Fn~ continue;
5"]PwC if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
~+V]MT {
SL>>]A,E<` SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
>c8zMd bProcessed=TRUE;
VBBqoyP
h }
;x|4Tm }
Js'COO }
Xl@nv9m else if((lParam&0xc000ffff)==1){ //有键按下
"JbFbcj switch(wParam)
GcHWalm {
Uiv;0Tovl case VK_MENU:
nU||Jg MaskBits|=ALTBIT;
VOp8 ,! break;
%U-KQI0 case VK_CONTROL:
73 Tg{~ MaskBits|=CTRLBIT;
O/iew3YF break;
Xj?j1R>GB case VK_SHIFT:
%pe7[/ MaskBits|=SHIFTBIT;
nNq| v=L break;
?)5}v4b default: //judge the key and send message
Bn}@wO break;
q yQPR }
s[8<@I*u for(int index=0;index<MAX_KEY;index++){
z2wR]G5! if(hCallWnd[index]==NULL)
Q^ bG1p//. continue;
h&;\ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
]e7D"" {
+SZ#s:#SE SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
~$YFfv>
bProcessed=TRUE;
gXc&uR0S }
xBR2tDi% }
b;Q
cBGwKT }
(:vY:-\ bO if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
!> for(int index=0;index<MAX_KEY;index++){
%fK"g2: if(hCallWnd[index]==NULL)
r]kLe2r:B continue;
1!0BE8s"@ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
d+[hB4!l2 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
YmNBtGhT //lParam的意义可看MSDN中WM_KEYDOWN部分
W(a=ev2sa }
O9:vPbn }
F~)xZN3= }
!N?|[n1 return CallNextHookEx( hHook, nCode, wParam, lParam );
`b# w3 2 }
Bn-%).-ED _+.z2} M 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:
.ye5;A} @1^iWM j BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
gy_n=jhi+ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
52{jq18& /$/\$f$ 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:
OB;AgE@ LtXFGPQ f LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
V~NS<!+q {
8{epy if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
fW <qp {
L`yS' //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
rR^VW^|f SaveBmp();
3#^xxEu return FALSE;
k0{Mq<V*% }
.' 3;Z'%"g …… //其它处理及默认处理
z*I= }
+Y'(,J +c+#InsY C4#'`8E 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。
"Do9gW CdC&y}u 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。
n)^B0DnIk k%VV(P]sT 二、编程步骤
0 \&4? ,^`+mP 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";
=cX&H oju4.1 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
!E4YUEY6 7:9WiN5b 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;
{CYFM[V yLipuMNV 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;
$l7
<j_C xzAyE5GL> 5、 添加代码,编译运行程序。
{LrezE4 &5~bJ]P 三、程序代码
}Q/xBC) JY4 +MApN ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
xpRQ"6 #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
AQ'~EbH( #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
#e{l:!uS\ #if _MSC_VER > 1000
Kw"7M~ #pragma once
o3qBRT0[R #endif // _MSC_VER > 1000
-jFvDf,M,D #ifndef __AFXWIN_H__
}9:d(B9; #error include 'stdafx.h' before including this file for PCH
G#
.z((Rj #endif
cQA;Y!Q# #include "resource.h" // main symbols
k`'^e/ class CHookApp : public CWinApp
D)K/zh) {
'\[GquK;P public:
ikw_t? CHookApp();
O{%yO=`r // Overrides
yAW%y // ClassWizard generated virtual function overrides
<x53b/ft //{{AFX_VIRTUAL(CHookApp)
@'7'3+ c public:
,4)zn6tC virtual BOOL InitInstance();
C8e{9CF virtual int ExitInstance();
qI5_@[S* //}}AFX_VIRTUAL
3tA6r //{{AFX_MSG(CHookApp)
ZdY:I;)s // NOTE - the ClassWizard will add and remove member functions here.
0\k2F,:%4 // DO NOT EDIT what you see in these blocks of generated code !
"!+q0l1]@ //}}AFX_MSG
7??+8T#n* DECLARE_MESSAGE_MAP()
,_F1g<^@u };
(w6 024~ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
6Y`eYp5A BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
6L}$R`s5H BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
;Ze}i/l BOOL InitHotkey();
VNp[J'a>VZ BOOL UnInit();
,1a6u3f, #endif
18zv]v
% 1I<fp $h //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
u?&P6|J& #include "stdafx.h"
L^Fni~ #include "hook.h"
=j#uH`jgW #include <windowsx.h>
UQ}[2x(Kb #ifdef _DEBUG
eYOwdTrq #define new DEBUG_NEW
;S7MP`o@ #undef THIS_FILE
K_G(J> static char THIS_FILE[] = __FILE__;
e)zE*9 #endif
7:)= #define MAX_KEY 100
u$X[= #define CTRLBIT 0x04
to|O]h2*U2 #define ALTBIT 0x02
O>IY<]x>L #define SHIFTBIT 0x01
`gDpb.=Y #pragma data_seg("shareddata")
%7xx"$P:R HHOOK hHook =NULL;
g~rZ= UINT nHookCount =0;
l#Ipo5= static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
9l]+rs+ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
nxS|] static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
h-].?X,]Q static int KeyCount =0;
wzwEYZN(q static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
W_Z%CBjcT #pragma data_seg()
sC(IeGbX HINSTANCE hins;
0r*E$|zZ void VerifyWindow();
*%=BcV+, BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
|a*VoMZ //{{AFX_MSG_MAP(CHookApp)
bqWo*>l // NOTE - the ClassWizard will add and remove mapping macros here.
+C' u!^) // DO NOT EDIT what you see in these blocks of generated code!
|A0BYzlVc //}}AFX_MSG_MAP
F>dB@V- END_MESSAGE_MAP()
^Vso`(Ss !KKkw4 CHookApp::CHookApp()
(y*7
gf {
PzMJ^H{ // TODO: add construction code here,
MzM"r"u // Place all significant initialization in InitInstance
7/&i'y }
3LN+gXmU
@tGju\E"o CHookApp theApp;
<2"' R(4", LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
#>iBu:\J {
ywTt<;
BOOL bProcessed=FALSE;
O2g9<H if(HC_ACTION==nCode)
;h<(vc3@f {
zo6|1xq if((lParam&0xc0000000)==0xc0000000){// Key up
bA!n; switch(wParam)
w$[&ejFb {
qIS9.AL case VK_MENU:
K|,P MaskBits&=~ALTBIT;
!}[}YY?',i break;
[%
\>FT[ case VK_CONTROL:
`u$
Rd MaskBits&=~CTRLBIT;
H=RzY-\a% break;
X'Q?Mh case VK_SHIFT:
]Wr2I M MaskBits&=~SHIFTBIT;
<`rmQ`(}s break;
%A64AJZ default: //judge the key and send message
KSDz3qe break;
b+Sq[ }
`?E|frz[ for(int index=0;index<MAX_KEY;index++){
`?f6~$1 if(hCallWnd[index]==NULL)
+O"!* continue;
)O\w'|$G if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
10R#}~D {
.);~H# SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
ndg1E;> bProcessed=TRUE;
S52'!WTq }
VzD LG LH }
J_NY:B }
H1>~,zc>E else if((lParam&0xc000ffff)==1){ //Key down
{*mf Is switch(wParam)
7+
+Fak {
K</EVt,U~ case VK_MENU:
#NQpr MaskBits|=ALTBIT;
]8@s+N break;
J>Pc@,y case VK_CONTROL:
PL} Wu= MaskBits|=CTRLBIT;
_E'F break;
A.tXAOM(VW case VK_SHIFT:
nVB.sab MaskBits|=SHIFTBIT;
:j^IXZW break;
"o_s=^U default: //judge the key and send message
C 2t] break;
dhrh "x_?: }
b3. for(int index=0;index<MAX_KEY;index++)
;>hRj! {
)|3BS` if(hCallWnd[index]==NULL)
B|d-3\sn continue;
Y*VF1M,2_ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
:m.6a4vx {
)R6h
1 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
=z>d GIT1 bProcessed=TRUE;
`vjn,2S} }
)XCG4-1 }
`]~1pc }
{g9*t}l4 if(!bProcessed){
{E=BFs for(int index=0;index<MAX_KEY;index++){
$, hHR: if(hCallWnd[index]==NULL)
.`p,pt; continue;
B7x(<!B if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
5PY4PT=G SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
`PY=B$?{4 }
FEY_(70 }
|\.:h":!0~ }
\-Vja{J] return CallNextHookEx( hHook, nCode, wParam, lParam );
H(?)v.% }
Ec/&?|$ tJBj9{ BOOL InitHotkey()
^?M# |> {
j]HzI{7y if(hHook!=NULL){
AQ%B&Q(V1 nHookCount++;
K g6hySb return TRUE;
lbs0i }
5Ve`j,`=< else
hGU
m7 hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
cN% r\ if(hHook!=NULL)
)J^5?A nHookCount++;
,V^2Oa return (hHook!=NULL);
1X5MknA }
:$6mS[@| BOOL UnInit()
QmgO00{ {
lA{JpH_Y8s if(nHookCount>1){
.;\uh$c nHookCount--;
p=!12t return TRUE;
^>Vl@cW0uz }
A"tE~m;"7 BOOL unhooked = UnhookWindowsHookEx(hHook);
}~NM\rm if(unhooked==TRUE){
CCHGd&\Z nHookCount=0;
Nl]_Ie6 hHook=NULL;
aD^jlt }
NufRd/q return unhooked;
w#v-h3XcF }
}j$tFFVi~ MgO_gFr BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
^HhV?Iqg {
n\ 'PNB BOOL bAdded=FALSE;
bL`>#M_^ for(int index=0;index<MAX_KEY;index++){
%W}YtDf\ if(hCallWnd[index]==0){
hbdB67, hCallWnd[index]=hWnd;
8]K+,0m6 HotKey[index]=cKey;
)%q!XM HotKeyMask[index]=cMask;
Tw,|ZA4XH bAdded=TRUE;
,ZI#p6 KeyCount++;
|A.nP9 hW break;
dVMduo }
S
awf]/ }
:F8h}\a* return bAdded;
mxnu\@}( }
dQn,0 =AcK9?%5 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
}}qY,@eeX {
2BKiA[
;; BOOL bRemoved=FALSE;
kyi"U A82 for(int index=0;index<MAX_KEY;index++){
+iqzj-e&e[ if(hCallWnd[index]==hWnd){
1B#iJZ} if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
`@xnpA]l hCallWnd[index]=NULL;
f
AY(ro9Q( HotKey[index]=0;
7@R^B =pb HotKeyMask[index]=0;
B&QEt[=s bRemoved=TRUE;
6&+}Hhe KeyCount--;
0.\}D:x(z break;
i>7]9gBm1q }
)3f<0C> }
K=!
C\T"I% }
:yw8_D3 return bRemoved;
XXw>h4hl }
NQxx_3*4O D GL=\ void VerifyWindow()
[Kg3:]2A {
C);3GPp for(int i=0;i<MAX_KEY;i++){
XRmE if(hCallWnd
!=NULL){ \_(|$Dhq
if(!IsWindow(hCallWnd)){ nx(jYXVT
hCallWnd=NULL; T[evh]koB
HotKey=0; C#V_Gb
HotKeyMask=0; }uwZS=pw
KeyCount--; 3*T/ 7\
} C|V5@O?;&
} g"~`\xhx
} EQe$~}[
} SdF+b+P]
J%]5C}v \
BOOL CHookApp::InitInstance() 1#3eY?Nb
{ K]1|#`n
AFX_MANAGE_STATE(AfxGetStaticModuleState()); b")O#v.
hins=AfxGetInstanceHandle(); Z;z,dw
InitHotkey(); #@' B\!<@=
return CWinApp::InitInstance(); JXjH}C
} ^RE[5h6^q
L&KL]n
int CHookApp::ExitInstance() P2&0bNY
{ HVdB*QEH
VerifyWindow(); xS(VgP&YGO
UnInit(); Uw]o9 e0S
return CWinApp::ExitInstance(); }vU^gPH
} 7~r_nP_
|{ =Jp<}s
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file I s|_
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) ~ z^49Ys:
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ ;?q-]J?
#if _MSC_VER > 1000 j115:f
#pragma once ]Q,&7D
Ah
#endif // _MSC_VER > 1000 F~0iJnF
M6ZXq6J
class CCaptureDlg : public CDialog >;]S+^dXY
{ !3<b#QAXRG
// Construction p1[|5r5Day
public:
!<HF764@`
BOOL bTray; 1g,Ofr
BOOL bRegistered; B}P!WRNmln
BOOL RegisterHotkey(); fRxn,HyV
UCHAR cKey; 7|"l/s9,
UCHAR cMask; Y3#8]Z_"}O
void DeleteIcon(); W9{i ~.zo
void AddIcon(); ^I9U<iNIL
UINT nCount; Adet5m.|[8
void SaveBmp(); 2I3H?Lrx!m
CCaptureDlg(CWnd* pParent = NULL); // standard constructor f*:N*cC
// Dialog Data wy^mh.= UX
//{{AFX_DATA(CCaptureDlg) /l$fQ:l
enum { IDD = IDD_CAPTURE_DIALOG }; mG1!~}[
CComboBox m_Key; GPizR|}h
BOOL m_bControl; ~$ Po3]{s
BOOL m_bAlt; E^Ch;)j|
BOOL m_bShift; M;W&#Fz%
CString m_Path; 03AQB;.
CString m_Number; 3s?ZyQy
//}}AFX_DATA KYy oN
// ClassWizard generated virtual function overrides Q@|"xKa
//{{AFX_VIRTUAL(CCaptureDlg) >sdF:(JV&
public: #S]O|$&*
virtual BOOL PreTranslateMessage(MSG* pMsg); *%\Xw*\0
protected: W6`_lGTj
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support A~v[6*~>
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); Y
O|hwhe_
//}}AFX_VIRTUAL M?Fv'YE
// Implementation Lp3pJE
protected: MR: H3
HICON m_hIcon; )y6
// Generated message map functions }O+S}Hbwy
//{{AFX_MSG(CCaptureDlg) :#\jx
virtual BOOL OnInitDialog(); <pXOE-G5
afx_msg void OnSysCommand(UINT nID, LPARAM lParam); 1;+77<