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:
]b&qC
(
FC8=
ru 一、实现方法
ou&7v<)x4 g[xn0rG 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:
QV%eTA P$;_YLr #pragma data_seg("shareddata")
@ j4~`~8 HHOOK hHook =NULL; //钩子句柄
FEg&EYI
UINT nHookCount =0; //挂接的程序数目
;\+A6(GX{ static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
VoUAFEcs static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
]p~,C*UH0 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
s|8_R; static int KeyCount =0;
W;wu2 ' static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
y
`w5u.' #pragma data_seg()
~E7=c3:" DfP
vi1 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。
?Wp{tB9N0 iW<B1'dp 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:
rB%acTCz=[ LaiUf_W #X BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
F%QVn. cKey,UCHAR cMask)
Y3I+TI>x {
:j,e0#+sA BOOL bAdded=FALSE;
)Ikx0vDFQ for(int index=0;index<MAX_KEY;index++){
u7<s_M3%N if(hCallWnd[index]==0){
:ITz\m hCallWnd[index]=hWnd;
xlaBOK a% HotKey[index]=cKey;
fM)R O7 HotKeyMask[index]=cMask;
Y1vSwS%{T bAdded=TRUE;
"^ cn9AG{ KeyCount++;
nZM|8 break;
} Pc6_# }
Lw.N3!e[ }
/z+}xRS return bAdded;
TNV# }
# 1,(I //删除热键
u37@9 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
9Kyr/6w4-k {
q-}J0vu\K BOOL bRemoved=FALSE;
x_\e&"x for(int index=0;index<MAX_KEY;index++){
g=:C/>g if(hCallWnd[index]==hWnd){
Jj'~\j if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
3u8H F- hCallWnd[index]=NULL;
@4b"0ne}h HotKey[index]=0;
_A\c 6# HotKeyMask[index]=0;
@hWt.qO3s bRemoved=TRUE;
T;}pMRd% KeyCount--;
"Gxf[6B break;
/cDla5eej }
sEL[d2oO }
7{XI^I:n }
nlK"2/W return bRemoved;
3%xj-7z
W }
?+b )=Z 0*8[m+j1 (Y!@,rKd DLL中的钩子函数如下:
1<
;<? F\&R nDJ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
^'C1VQ% {
l>S~)FNwXJ BOOL bProcessed=FALSE;
p}}o#a~V), if(HC_ACTION==nCode)
j#0@%d {
+kQ$X{+;8 if((lParam&0xc0000000)==0xc0000000){// 有键松开
Qg9 N?e{z switch(wParam)
!5Kv9P79 {
O%y. case VK_MENU:
a4L8MgF&$- MaskBits&=~ALTBIT;
W[:
n*h break;
-}{c;pT case VK_CONTROL:
~k4S~!(U0 MaskBits&=~CTRLBIT;
U*=ebZno break;
](@Tbm8 case VK_SHIFT:
Y+syc dq MaskBits&=~SHIFTBIT;
vVmoV0kGt break;
_CBG? default: //judge the key and send message
DnP>ed"M! break;
*obBo6!zM }
NI\jGR. for(int index=0;index<MAX_KEY;index++){
kc\^xq~ if(hCallWnd[index]==NULL)
)&<BQIv9/ continue;
8/x@|rjW if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
3@*J=LGhKc {
*pCT34'-- SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
{Tl5,CAz bProcessed=TRUE;
m@R!o }
|vw0:\/H }
_<|NVweFS }
)"2)r{7: else if((lParam&0xc000ffff)==1){ //有键按下
r*fZS$e switch(wParam)
HP^<2?K {
L]3 V)`} case VK_MENU:
!v;N@C3C MaskBits|=ALTBIT;
a_P8!pk+5 break;
-uXf?sTV case VK_CONTROL:
0qqk:h MaskBits|=CTRLBIT;
'.r_6X$7Jt break;
%{WS7(si case VK_SHIFT:
h5e(Avk MaskBits|=SHIFTBIT;
`h}fS4CO break;
I{U7BZy default: //judge the key and send message
_8Cw_ break;
;fw}<M!6 }
nj$TdwZbK for(int index=0;index<MAX_KEY;index++){
zgXg-cr if(hCallWnd[index]==NULL)
S<H2e{~ continue;
"`qmeZ$rg if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
d(9ZopJrQ {
GX?R# cf SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
YEH /22 bProcessed=TRUE;
~(OG3`W! }
)voJq\Y)% }
(Ild>_Tdb` }
^3"~
T if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
!Hq$7j_ for(int index=0;index<MAX_KEY;index++){
D])&> if(hCallWnd[index]==NULL)
NM
FgCL continue;
/bdL.Y# V if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
"&Q sv-9t SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Me;XG?` //lParam的意义可看MSDN中WM_KEYDOWN部分
Q1kZ+b& }
Fnqj^5 }
e= { ?d6 }
aSse'
C<a return CallNextHookEx( hHook, nCode, wParam, lParam );
HxUJ 0Q }
RE._Ov> u~rPqBT{d3 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
d1jg3{pwA 9'5< b BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
/
R-1s BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
z}BuR*WSY{ gQQve{' 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
6;C2^J @ =W*Ro+wWb LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
w`GjQIA {
4Sz2
9\X if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
ppuJC'GW {
a#D \8; //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
we0haK SaveBmp();
bV$g]->4e return FALSE;
V=gu'~ }
G#L6; …… //其它处理及默认处理
L,yq'>*5s }
|F4)&xN\ {3T&6 LA )Vz=:.D 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。
j];#=+ I)\{?LdHR 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%#w1k 5d;(D i5z 二、编程步骤
_WGWU7h T|&u? 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";
zh{I;~syh },=ORIB B: 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
!'C8sNs )EK\3q 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;
,V9r2QY d(j
g
"@ 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;
#nQboTB@ hWiHKR] 5、 添加代码,编译运行程序。
+y_V$q$G HJ!!" 三、程序代码
3!h 3flE y: ] ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
peew<SX #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
^jXKM!}-E #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
[s+FX5' K #if _MSC_VER > 1000
hh$i1n #pragma once
qYPgn_ #endif // _MSC_VER > 1000
P_P~c~o #ifndef __AFXWIN_H__
sC ?e%B #error include 'stdafx.h' before including this file for PCH
4QE")Ge #endif
cpPS8V #include "resource.h" // main symbols
?k=)T]-} class CHookApp : public CWinApp
QO>)ug+ {
"^ aSONz public:
uG+eF CHookApp();
<vzU}JA\ // Overrides
l$!Z};mw0E // ClassWizard generated virtual function overrides
@7t*X-P.;- //{{AFX_VIRTUAL(CHookApp)
VrKLEN\ public:
8/}S/$ virtual BOOL InitInstance();
m;sYg virtual int ExitInstance();
-j^G4J //}}AFX_VIRTUAL
MM~4D //{{AFX_MSG(CHookApp)
2h)* // NOTE - the ClassWizard will add and remove member functions here.
bv``PSb3 // DO NOT EDIT what you see in these blocks of generated code !
:4>LtfA //}}AFX_MSG
lrgvY>E0 DECLARE_MESSAGE_MAP()
<^+&A7Q-_ };
PkOtg[Z LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
S,s") )A1 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
>p3S,2SM BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
xw*/8.Md6f BOOL InitHotkey();
^J@
Xsl BOOL UnInit();
^C8f( #endif
2bf#L?5g/ _Ry //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
'l1cuAP!+ #include "stdafx.h"
3ZAzv en #include "hook.h"
_2<k,Dl;RY #include <windowsx.h>
g:>dF# #ifdef _DEBUG
8WwLKZ} #define new DEBUG_NEW
AVp"<Uv #undef THIS_FILE
v8THJf static char THIS_FILE[] = __FILE__;
,*wj~NE #endif
"; ?^gA #define MAX_KEY 100
s=XqI@ #define CTRLBIT 0x04
H"rIOoxf #define ALTBIT 0x02
+s5Yg,4*
#define SHIFTBIT 0x01
C2?p>S/q #pragma data_seg("shareddata")
EkP(]F HHOOK hHook =NULL;
6
wD UINT nHookCount =0;
-vS7 %Fbr static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
{Yti static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
4hV~
ir static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
,)}-mu static int KeyCount =0;
gk"J+uM static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
YifTC-Q; #pragma data_seg()
h{Y#. j~aS HINSTANCE hins;
v?4MndR void VerifyWindow();
SVT'fPm1M BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
x;/%`gKn8 //{{AFX_MSG_MAP(CHookApp)
zj'uKBDl // NOTE - the ClassWizard will add and remove mapping macros here.
N Z~"2~Hh // DO NOT EDIT what you see in these blocks of generated code!
7A>glZ/x //}}AFX_MSG_MAP
SZC1$..2T END_MESSAGE_MAP()
mr`EcO0 (2%z9W CHookApp::CHookApp()
xW'(]Z7_ {
Psu*t%nQ?A // TODO: add construction code here,
5I@2U vV8 // Place all significant initialization in InitInstance
X6:
c- }
KfLp cV :S{+|4pH CHookApp theApp;
(:T\< LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
$Z^HI {
i^DZK&B@u BOOL bProcessed=FALSE;
C9FQo7 if(HC_ACTION==nCode)
626!6E;T {
"# BI" if((lParam&0xc0000000)==0xc0000000){// Key up
~m.@{Do0p switch(wParam)
=
eDi8A*~ {
m|+g_JZ case VK_MENU:
3.s.&^ MaskBits&=~ALTBIT;
,_2ZKO/k$ break;
QWV12t$v case VK_CONTROL:
UL.x*@o MaskBits&=~CTRLBIT;
3ud_d> break;
G>);8T%l case VK_SHIFT:
cRhu]fv() MaskBits&=~SHIFTBIT;
/
`Glf| break;
A7qKY-4B default: //judge the key and send message
.`3O4]N[ break;
k*3F7']8 }
a.yCd/ for(int index=0;index<MAX_KEY;index++){
z.q^`01/H if(hCallWnd[index]==NULL)
s8/y|HN^ continue;
0qj:v"~Q if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
]%L?b-e {
+(-L SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
VNcxST15a bProcessed=TRUE;
:Ej#qYi }
_Fz]QxO }
=x/Ap1 }
y7quKv7L} else if((lParam&0xc000ffff)==1){ //Key down
zMf. switch(wParam)
{m)$ b {
W
h^9 Aq case VK_MENU:
'*~_!lE5 MaskBits|=ALTBIT;
? %9-5"U[ break;
O#g'4 S case VK_CONTROL:
|a3v!va MaskBits|=CTRLBIT;
p(jY2&g break;
i'w8Li case VK_SHIFT:
RObo4 MaskBits|=SHIFTBIT;
U7)#9qS4 break;
0pO{ {F default: //judge the key and send message
{`FkiB` i break;
}e7os0;s }
O_zW/# for(int index=0;index<MAX_KEY;index++)
ewo]-BQS {
O%g
Q if(hCallWnd[index]==NULL)
aC\O'KcH continue;
j20/Q)=h if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
uPVM>xf>w {
V`c"q.8 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
-B`Nkc
bProcessed=TRUE;
?IKSSe#, }
IAHQT<] }
'5m4kDs }
+8|9&v` if(!bProcessed){
U *:ju+)k for(int index=0;index<MAX_KEY;index++){
oj(st{, if(hCallWnd[index]==NULL)
;u-[%(00S continue;
2<T/N if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
!(F?Np Am SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
9Tg
k= }
l;SXR <EU }
I7#^'/ }
3xz|d`A return CallNextHookEx( hHook, nCode, wParam, lParam );
Zsn@O2 }
|ms. lhC^Upqw BOOL InitHotkey()
GJ{XlH {
I&6M{,rnM if(hHook!=NULL){
r;9 V7C nHookCount++;
{4$aA* return TRUE;
DDq?4 }
i-}Tt<^ else
TILH[r&Jg hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
ICEyz|
C if(hHook!=NULL)
OQIr" nHookCount++;
VRZqY7j}g return (hHook!=NULL);
'T|EwrS j }
~:
fSD0 BOOL UnInit()
I.'/!11> {
zsLMROo3 if(nHookCount>1){
m^~5Xr" nHookCount--;
t2iQ[`/?~ return TRUE;
r1Hh @sxn }
l;rA}?,.^ BOOL unhooked = UnhookWindowsHookEx(hHook);
x_x_TEyy h if(unhooked==TRUE){
0@um nHookCount=0;
#+N_wIP4 hHook=NULL;
A>8~deZ9 }
{;|pcx\L6~ return unhooked;
01&@8z'E }
(<
>L fn f62rm[ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
w59q* 2 {
fk9q 3 BOOL bAdded=FALSE;
ZXN`8!]& for(int index=0;index<MAX_KEY;index++){
!Eg2#a ? if(hCallWnd[index]==0){
gnkeJ}K hCallWnd[index]=hWnd;
%#o@ c HotKey[index]=cKey;
o:&8H>(hn] HotKeyMask[index]=cMask;
p>i8aN bAdded=TRUE;
Y<jX[ET! KeyCount++;
spTz}p^\O break;
=1k%T {> }
2
6DX4 }
8#HnV%|N return bAdded;
}30Sb&" }
f _$hK9I eEfGH BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
9XYm8g'X {
.vctuy& BOOL bRemoved=FALSE;
:nR80] for(int index=0;index<MAX_KEY;index++){
"G~!J\ if(hCallWnd[index]==hWnd){
^pH8'^n if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
d"IZt;s/, hCallWnd[index]=NULL;
)hl7)~S< HotKey[index]=0;
n.qT7d( HotKeyMask[index]=0;
\<(EV,m2 bRemoved=TRUE;
n$XEazUb0N KeyCount--;
:4-,Ru1C" break;
_3D9>8tzE7 }
VKZP\]$XG }
m?4hEwQxf }
I]i(
B+D return bRemoved;
JV@G9PT }
3!\h'5{ |OAM;@jH void VerifyWindow()
qjh k#\y {
Woj5
yr for(int i=0;i<MAX_KEY;i++){
Zj-U^6^L if(hCallWnd
!=NULL){ 1x=x,lcL
if(!IsWindow(hCallWnd)){ 7V8k =
hCallWnd=NULL; (_!I2"Q*
HotKey=0; vb?.`B_>&
HotKeyMask=0; =Gu&0f
KeyCount--; u8.Tu7~
} .)$MZyo
} z/+{QBen8
}
6WT3-@d
} TE$6=;
ZfX$q\7
BOOL CHookApp::InitInstance() UimofFmI%
{ j'U1lEZm2
AFX_MANAGE_STATE(AfxGetStaticModuleState()); K:jn^JN$
hins=AfxGetInstanceHandle(); i!}6FBZ
InitHotkey(); Axns
return CWinApp::InitInstance(); 1KrJS(.
} 8#lq:
3~bB2APk
int CHookApp::ExitInstance() WA,D=)GP
{ gSw4\ R
VerifyWindow(); vG'#5%,|
UnInit(); 8Th,C{
return CWinApp::ExitInstance(); O1c:X7lHc
} @XolFOL"f"
`_ 1~[t
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file CEI"p2
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) * 30K}&T
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ B~ i
#if _MSC_VER > 1000 ]vB\yQE
#pragma once D-LOjMe
#endif // _MSC_VER > 1000 I=#`8deH(
{&>rKCi
class CCaptureDlg : public CDialog Cs[d:T
{ " (O3B
// Construction )dX(0E4Td/
public: bY.VNA
BOOL bTray; #@OPi6.#!<
BOOL bRegistered; -JF^`hBD-
BOOL RegisterHotkey(); ; veD?|
UCHAR cKey; n<j+KD#a
UCHAR cMask; dt:$:,"
void DeleteIcon(); eGq7+
void AddIcon(); KzO"$+M
UINT nCount; 7~QI4'e
void SaveBmp(); m!Z<\2OP
CCaptureDlg(CWnd* pParent = NULL); // standard constructor hBpa"0F
// Dialog Data jhf3(hx&F
//{{AFX_DATA(CCaptureDlg) j;y~vX b
enum { IDD = IDD_CAPTURE_DIALOG }; M yHv>
CComboBox m_Key; pg4pfi^__V
BOOL m_bControl; G2kU_
BOOL m_bAlt; ^@AyC"K
BOOL m_bShift; -)oUb=Lk{
CString m_Path; [ ,Go*r
CString m_Number; N4C7I1ihq
//}}AFX_DATA =n"k gn
// ClassWizard generated virtual function overrides |EX=Rj*
//{{AFX_VIRTUAL(CCaptureDlg) KH;~VR8"/
public: O6G'!h\F
virtual BOOL PreTranslateMessage(MSG* pMsg); ]$Z:^"JS3
protected: s2G9}i{
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support T9Q3I
virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam); o=($'(1
//}}AFX_VIRTUAL hA5')te<