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:
]q/USVj{
I.it4~]H 一、实现方法
D9!$H!T _ ?hYWxWW 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
J3$@: S' tGF3Hw^mS #pragma data_seg("shareddata")
tac\Ki? HHOOK hHook =NULL; //钩子句柄
6G{ Q@ UINT nHookCount =0; //挂接的程序数目
$e:bDZ(hjj static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
#I\" 'n5M static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
V3ExS1fNf static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
<==6fc>s static int KeyCount =0;
gBOF#"- static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
Hyi'z 1 #pragma data_seg()
odn3*{c{x 'V\V=yc1 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
R{pF IyR 4hzdc]
a DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
@@ cc/S }b]eiPWN BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
7&u$^c S( cKey,UCHAR cMask)
WEtPIHruyt {
!|8"}ZF BOOL bAdded=FALSE;
&@=W+A=c~ for(int index=0;index<MAX_KEY;index++){
#7@p if(hCallWnd[index]==0){
[S9"' ^H hCallWnd[index]=hWnd;
BZ(I]:oDL HotKey[index]=cKey;
1x8wQ/p| HotKeyMask[index]=cMask;
^bq,+1;@Q bAdded=TRUE;
5v^tPGg4 KeyCount++;
}G<~Cx5[ break;
rU6A^p\, }
FIUQQQ\3 }
/ }*}r return bAdded;
u:^sEk"Lk' }
<GF^VT|Ce //删除热键
!t}yoN
n| BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Z\cD98B# {
]r'D BOOL bRemoved=FALSE;
kK/XYC
0D for(int index=0;index<MAX_KEY;index++){
qae|?z if(hCallWnd[index]==hWnd){
MBAj.J if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
Qe-PW9C hCallWnd[index]=NULL;
<W+9h0c HotKey[index]=0;
AH_qZTv0{Q HotKeyMask[index]=0;
Wb[k2V bRemoved=TRUE;
("{"8 KeyCount--;
}Rw6+; break;
X4{<{D`0t8 }
S&QXf<v }
BWNI|pq)v }
SM8_C!h: return bRemoved;
>GLoeCRNu }
pw`'q(ad 2[qoqd( `F3wO! DLL中的钩子函数如下:
E^$8nqCL: lQEsa45 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
EWQLLH "h {
Y[H769 BOOL bProcessed=FALSE;
@_W13@| if(HC_ACTION==nCode)
a&UzIFdB {
+(y8q if((lParam&0xc0000000)==0xc0000000){// 有键松开
J5';Hb) switch(wParam)
\+=`o .2 {
mxpj<^n} case VK_MENU:
q;UGiB^(A MaskBits&=~ALTBIT;
yDWBrN._ break;
\BN$WV case VK_CONTROL:
{ {:Fs MaskBits&=~CTRLBIT;
%ZX9YuXQ break;
:(wFNK/0{ case VK_SHIFT:
k1ja ([Q MaskBits&=~SHIFTBIT;
FBbaLqgVF{ break;
(=%0$(S> default: //judge the key and send message
<fF|AbC: break;
n oM=8C&U }
1vxQ`) a for(int index=0;index<MAX_KEY;index++){
Gp+\}<^Z if(hCallWnd[index]==NULL)
'.M4yif\g continue;
43]y]/do if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
v5@M 34 {
&AWrM{e SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
*")*w> R bProcessed=TRUE;
e<*qaUI }
F-oe49p5e }
>\w]i*% }
Cs
y,3XG else if((lParam&0xc000ffff)==1){ //有键按下
IN.g switch(wParam)
W)J MV {
?c+$9 case VK_MENU:
*8po0s MaskBits|=ALTBIT;
f*xr0l break;
:0QDV~bs case VK_CONTROL:
^;rjs|`K# MaskBits|=CTRLBIT;
CWocb=E break;
0{vH .b
@ case VK_SHIFT:
AI Kz]J0; MaskBits|=SHIFTBIT;
wc.=`Me break;
iy_Y!wZ{ default: //judge the key and send message
'&dT break;
"j8)l4} }
O5Z9`_9< for(int index=0;index<MAX_KEY;index++){
OM{^F=Ap if(hCallWnd[index]==NULL)
@d^Z^H*Yv continue;
{L~dER if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
"|[9 Q? {
Z) 2d4:uv SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
~LZrhwVj$ bProcessed=TRUE;
GZ,MC?W }
=B5{ 7g\ }
x^EW'-a }
7 4MxU if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
Mgi~j.[ for(int index=0;index<MAX_KEY;index++){
;+(VO if(hCallWnd[index]==NULL)
q6w)zTpJGJ continue;
d;]mwLB0 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
E #B$.K SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
J-<_e?? //lParam的意义可看MSDN中WM_KEYDOWN部分
Tjq1[Wq }
3Ovx)qKxd }
n6+h;+8;] }
T!ZjgCY} return CallNextHookEx( hHook, nCode, wParam, lParam );
JJ%@m;~ }
CbC[aVA= 1[8^JVC>6 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
i?;#ZNh s)`(@"{ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
6lv@4R^u BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
kLF`6ZXtd [rWBVfm 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
=gD)j&~}_ X:$vP'B> LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
yF?O+9R
A {
)Uy%iE* if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
!Q15qvRS {
*DC/O(
0 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
1n[)({OQ SaveBmp();
8.n#@% return FALSE;
vxTn }
_:=\h5}8 …… //其它处理及默认处理
z!O;s
ep?/ }
6V%}2YE?X r KUtTj 'jfE?ngt 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。
z k/`Uz 6PYt>r&TO 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。
W"\}## 6j XDLI 二、编程步骤
n]`]gLF\i #IvKI+" 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";
a1y<Y`SC9 'ia-h7QWS 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
{?0'(D7. I9qFXvqL 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;
/MY's&D( SsTBjIX 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;
O-
QT+] -dA9x~o 5、 添加代码,编译运行程序。
M,@M5o2u Nh }-6|M 三、程序代码
PdqvXc bE.<vF& ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
4@3 \Ihv #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
c-(RjQ~M5 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
'g)f5n a[ #if _MSC_VER > 1000
Lv['/!DJ| #pragma once
dN3^PK #endif // _MSC_VER > 1000
RU7+$Z0K #ifndef __AFXWIN_H__
C/Tk`C& #error include 'stdafx.h' before including this file for PCH
N=C t3 #endif
`e<IO_cg #include "resource.h" // main symbols
%xCL&}bY class CHookApp : public CWinApp
SoM,o]s#y {
JxtzI2 public:
Gg9s.]W CHookApp();
P|@[D=y // Overrides
i@nRZ$ K // ClassWizard generated virtual function overrides
iKE&yO3 //{{AFX_VIRTUAL(CHookApp)
Awxm[:r>^ public:
N^$q;% virtual BOOL InitInstance();
#%k_V+o3 virtual int ExitInstance();
8c-ys-"# //}}AFX_VIRTUAL
iv_3R}IbX //{{AFX_MSG(CHookApp)
JI]Lz1i // NOTE - the ClassWizard will add and remove member functions here.
9!n95 // DO NOT EDIT what you see in these blocks of generated code !
y EfAa6 //}}AFX_MSG
s(3u\#P DECLARE_MESSAGE_MAP()
m_oUl(pk };
'Xwv, LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
~6kF`}5 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
9;v3
(U+: BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
<Hr<QiAK BOOL InitHotkey();
#1E4
R}B BOOL UnInit();
\Hrcf +` #endif
YGOkqI *sU,waX //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
W7WHDL^ #include "stdafx.h"
\99'#]\_/E #include "hook.h"
]NTQF/ #include <windowsx.h>
G<-KwGy,D #ifdef _DEBUG
&,%n #define new DEBUG_NEW
JseKqJ?g #undef THIS_FILE
Jw}t~m3 static char THIS_FILE[] = __FILE__;
[;,E cw^ #endif
S1^/W-yoc~ #define MAX_KEY 100
r+ 8Tp|% #define CTRLBIT 0x04
Db|JR #define ALTBIT 0x02
VQH48{X #define SHIFTBIT 0x01
[k\VUg:P #pragma data_seg("shareddata")
/!5ohQlPJ HHOOK hHook =NULL;
PWl;pBo UINT nHookCount =0;
KBtqtE'(L static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
bT2c&VPCE static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
XLpn3sX$ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
*uRDB9#9, static int KeyCount =0;
E*5aLT5!, static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
*
cW%Q@lit #pragma data_seg()
^-PYP:* HINSTANCE hins;
"r@#3T$ void VerifyWindow();
5}hQIO&^% BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
z_xy*Iif //{{AFX_MSG_MAP(CHookApp)
9_5>MmiB // NOTE - the ClassWizard will add and remove mapping macros here.
5A`>3w{3n // DO NOT EDIT what you see in these blocks of generated code!
0Sd>*nC //}}AFX_MSG_MAP
ASoBa&vX END_MESSAGE_MAP()
p1niS:}j e_ epuki CHookApp::CHookApp()
j:1N&7<FU {
02;'"EmP$ // TODO: add construction code here,
Tdh.U{Nz // Place all significant initialization in InitInstance
>l)x~Bkf$j }
33lh~+C ,^c-}`!K CHookApp theApp;
Uz_ob9l<#H LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
,0h{RZKw {
qbq2Bi'a BOOL bProcessed=FALSE;
HLDv{G'7 if(HC_ACTION==nCode)
8/R$}b>< {
P{K\}+9F
if((lParam&0xc0000000)==0xc0000000){// Key up
5,MM`:{{ switch(wParam)
[rcM32 {
:!Q(v(M case VK_MENU:
Pzzzv^+ MaskBits&=~ALTBIT;
4K:Aqqhds break;
)fXw ~ case VK_CONTROL:
F~eYPaEKy! MaskBits&=~CTRLBIT;
z. hq2v break;
U9`Co&Z2 case VK_SHIFT:
n-M6~ MaskBits&=~SHIFTBIT;
>qy62:co break;
`$1A;wg< default: //judge the key and send message
TxQsi"0c break;
SHPDbBS }
d1g7:s9$0 for(int index=0;index<MAX_KEY;index++){
(G+)v[f if(hCallWnd[index]==NULL)
:^?-bppYW continue;
,/p+#|>C= if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
Ou4hAm91s {
$> QJ%v9+ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
{wSz >, bProcessed=TRUE;
nt>3 i! l }
/!Ag/SmS!9 }
P|ibUxSA~, }
j07A>G-= else if((lParam&0xc000ffff)==1){ //Key down
Cd^1E]O0{ switch(wParam)
q/*veL {
3:WHC3}W case VK_MENU:
<bW~!lv MaskBits|=ALTBIT;
<Sd ef^ break;
(kX:@9Pn case VK_CONTROL:
3;z1Hp2X MaskBits|=CTRLBIT;
uYlyU~M:D break;
m=h/A xW case VK_SHIFT:
!sI^Lh,Y MaskBits|=SHIFTBIT;
P*;[&Nn4 break;
9wfE^E1 default: //judge the key and send message
w8q
2f-K- break;
F#9^RA)9 }
ZGh6- / for(int index=0;index<MAX_KEY;index++)
<nk/w5nKL {
#o~C0`8!B= if(hCallWnd[index]==NULL)
%?V~7tHm> continue;
v\9f 8|K if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
`Zmdlp@ {
eW<NDI&b SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
`j'1V1 bProcessed=TRUE;
|AExaO"jk }
T-4dD }
3jfAv@I ~ }
n|H8O3@ if(!bProcessed){
0[YksNNl1 for(int index=0;index<MAX_KEY;index++){
!}x-o`a5 if(hCallWnd[index]==NULL)
mBye)q$ continue;
//r)dN^ if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
yZ=O+H SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
\kI{# }
X<Xiva85 }
WaX!y$/z }
0r$n return CallNextHookEx( hHook, nCode, wParam, lParam );
\uo{I~Qd }
G,WLca[ ]!"7k_ BOOL InitHotkey()
j7I?K
:op= {
H^o_B1 if(hHook!=NULL){
Y>c+j nHookCount++;
Rc9>^>w return TRUE;
1)97AkN(O }
a|]deJU^ else
.*"KCQGOgM hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
\TzBu?,v8 if(hHook!=NULL)
#:Q\ nHookCount++;
QS4~":D/C return (hHook!=NULL);
S~m8j|3K }
nRX'J5Q
m< BOOL UnInit()
(u@X5O(a {
/i_FA]Go if(nHookCount>1){
C
%j%>X` nHookCount--;
g 6?y{(1 return TRUE;
W%&s$b( }
?%ltoezf BOOL unhooked = UnhookWindowsHookEx(hHook);
I%Z=O= if(unhooked==TRUE){
b!J?>du nHookCount=0;
rR{KnM hHook=NULL;
CO,{/ }
gE*7[*2?t return unhooked;
zFYzus`> }
'O2/PU2_ Y HS/|- BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
yZoJD{'?Sw {
ON>l%Ae4G BOOL bAdded=FALSE;
ZhRdml4U2 for(int index=0;index<MAX_KEY;index++){
iM1E**WCtv if(hCallWnd[index]==0){
g^po$%I ' hCallWnd[index]=hWnd;
:YX5%6 HotKey[index]=cKey;
iN0'/)ar HotKeyMask[index]=cMask;
:T@} CJ bAdded=TRUE;
'F/uD1; KeyCount++;
c%wztP;L break;
jc!V|w^ }
%ib7)8Ki0 }
'vq0Tw5 return bAdded;
x{G 'IEf }
f4 +P2j ]TtID4qL BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
muK.x7zyl {
e6 <9`Xg BOOL bRemoved=FALSE;
TZg1,Z for(int index=0;index<MAX_KEY;index++){
t1yfSStp if(hCallWnd[index]==hWnd){
>@a7Zzl0H if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
77+3CME{' hCallWnd[index]=NULL;
@x[A^ HotKey[index]=0;
k%sxA HotKeyMask[index]=0;
P,G
:9x"e bRemoved=TRUE;
5w~J"P6jg KeyCount--;
y^Q);siSy break;
sUiO~<Ozpk }
oxnI/Z }
+l]>(k.2 }
M,oZ_tY% return bRemoved;
k7sD"xR3 }
dxS5-aWy9w Cd6th
F) void VerifyWindow()
33~8@]b {
y
GmFi for(int i=0;i<MAX_KEY;i++){
at\u7>;.^k if(hCallWnd
!=NULL){ ]j*uD317
if(!IsWindow(hCallWnd)){ :7Uv)@iUk
hCallWnd=NULL; '<e$ c
HotKey=0; 4}*.0'Hz
HotKeyMask=0; 9`^(M^|c
KeyCount--; k`z]l;:
} S|6i]/
} xjAU
Csq
} f4f)9n
} f?16%Rk<
(m2_Eh;
BOOL CHookApp::InitInstance() ?h|DeD!s
{ [yc7F0Aw
AFX_MANAGE_STATE(AfxGetStaticModuleState()); H _| re
hins=AfxGetInstanceHandle(); M*Q}^<E*
InitHotkey(); $n47DW&
return CWinApp::InitInstance(); Z?&ZgaSz
} /m^G 99N
:}#j-ZCC"
int CHookApp::ExitInstance() xDS]k]/(T
{ Z@*!0~NH=4
VerifyWindow(); *<"{(sAvk
UnInit(); *p\fb7Pu_3
return CWinApp::ExitInstance(); !4Sd ^"
} zITxJx
i]@k'2N
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file NweGK
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) im)r4={
9
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ v:w^$]4
#if _MSC_VER > 1000 \;Q!}_ K
#pragma once cBOt=vg,5
#endif // _MSC_VER > 1000 4?
rEO(SZ
1M55!b
class CCaptureDlg : public CDialog | (,{&\
{ =Uo*-EH
// Construction d{ B0a1P
public: bcxR7<T,"9
BOOL bTray; ,I]]52+?4
BOOL bRegistered; tqp i{e
BOOL RegisterHotkey(); 0G Q8}r
UCHAR cKey; 6g#E/{kQw
UCHAR cMask; X(8LhsP
void DeleteIcon(); iO18FfM_
void AddIcon(); -r~9'aEs
UINT nCount; <*/Z>Z_c2
void SaveBmp(); b=Ektq
CCaptureDlg(CWnd* pParent = NULL); // standard constructor @LS%uqs
// Dialog Data J*6B~)Sp@
//{{AFX_DATA(CCaptureDlg) 3Q7PY46
enum { IDD = IDD_CAPTURE_DIALOG }; 7Xh @%[
CComboBox m_Key; )"2eN3H/
BOOL m_bControl; ,4-],~T
BOOL m_bAlt; x'6i9]+r
BOOL m_bShift; 9JILK9mVO
CString m_Path; 8|L 5nQ
CString m_Number; &
\"cV0
//}}AFX_DATA W(-son~I
// ClassWizard generated virtual function overrides e(&u3 #7Nn
//{{AFX_VIRTUAL(CCaptureDlg) )Q}Q -Zt
public: R,OT\FQ<
virtual BOOL PreTranslateMessage(MSG* pMsg); \TDn q!)?
protected: Zz'g&ew