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:
ji8Rd"S
,f1wN{P 一、实现方法
eP2 y U {Y@[hoHtF 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:
>'T%=50YH ;I7Z*'5! #pragma data_seg("shareddata")
k
Z3tz?Du HHOOK hHook =NULL; //钩子句柄
;4_n:XUgo; UINT nHookCount =0; //挂接的程序数目
;|^fAc~9{r static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
*@ o3{0[Z static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
@1+/r?b static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
WIGb7}egR static int KeyCount =0;
?SAi tQ3 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
fBF}-{VX( #pragma data_seg()
iBi/9 L9kP8&&KK 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。
~8X'p6 LH_ 2oJ\ 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:
ec0vg.>p ZRHTvxf BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
uJO*aA{K cKey,UCHAR cMask)
/Yh([P> {
f6"j-IW[z BOOL bAdded=FALSE;
us cR/d
for(int index=0;index<MAX_KEY;index++){
ES~]rPVS if(hCallWnd[index]==0){
}n=NHHtJ hCallWnd[index]=hWnd;
bk?\=4B:E HotKey[index]=cKey;
VO`A HotKeyMask[index]=cMask;
) )F.|w bAdded=TRUE;
:d#NnR0^L KeyCount++;
Kaa*;T![ break;
/f[_]LeV] }
8vRiVJ8QS: }
lrE0)B5F return bAdded;
9j"\Lr*o" }
g3Q #B7A //删除热键
yS43>UK_W+ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
b?$09,{0 {
4TKi)0
#7 BOOL bRemoved=FALSE;
}cT}G;L'- for(int index=0;index<MAX_KEY;index++){
;H=6u if(hCallWnd[index]==hWnd){
2ya`2 m if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
*O5+?J Z! hCallWnd[index]=NULL;
OS
6 )` HotKey[index]=0;
s`B'vyoaa HotKeyMask[index]=0;
kMo)4Xp bRemoved=TRUE;
_e3'f:
KeyCount--;
5^dw!^d break;
`R> O5Rv }
1fy{@j(W }
=FbfV*K9 }
pUr[MnQLf return bRemoved;
7" [;M }
ts]7 + 6V x\DkS,O ' 7A7HDJ DLL中的钩子函数如下:
_#O?g=1 FCWphpz LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
JW\"S {
+Xp;T`,v BOOL bProcessed=FALSE;
{5udol5? if(HC_ACTION==nCode)
jveRiW@ {
~roHnJ> if((lParam&0xc0000000)==0xc0000000){// 有键松开
k +Oq$Pi switch(wParam)
z!+<m< {
a}K+w7VY\ case VK_MENU:
l)8 V:MK MaskBits&=~ALTBIT;
b{rmxtx break;
RtL<hD case VK_CONTROL:
B<LavX>F MaskBits&=~CTRLBIT;
%&XX*&
q break;
WFd2_oAT case VK_SHIFT:
iV5I MaskBits&=~SHIFTBIT;
/v{[Z&z break;
)rj mJ default: //judge the key and send message
[}2.CM break;
aK{\8L3] }
mSfhl(<L for(int index=0;index<MAX_KEY;index++){
l.x }I"tf if(hCallWnd[index]==NULL)
ECScx02 continue;
pJz8e&wyLM if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
ry
?2 o! {
cPcV[6)5K9 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
C=IH#E= bProcessed=TRUE;
S nHAY< }
l5[xJH }
".%LBs~$ }
!r*;R\!n2 else if((lParam&0xc000ffff)==1){ //有键按下
kPH^X}O$ switch(wParam)
Q/c
WV {
}|Tg_+ case VK_MENU:
LrMFzd}_O MaskBits|=ALTBIT;
-y?Z}5-rs break;
>@U<?wP case VK_CONTROL:
<o+
7U MaskBits|=CTRLBIT;
k+[KD >;1 break;
+c a296^ case VK_SHIFT:
-ZP&zOsDr MaskBits|=SHIFTBIT;
gKN_~{{OD break;
b3xkJ&Z default: //judge the key and send message
j/D)UWkR break;
RRqMwy>% }
Jche79B for(int index=0;index<MAX_KEY;index++){
o%%x'uC if(hCallWnd[index]==NULL)
i4n
b# continue;
Oq,.Kz if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
s jI[Vq {
s ;s-6%p SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
|WU`p bProcessed=TRUE;
e6HlOGPVQH }
tR*W-% }
Rr 4CcM }
/]zib@i if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
|OZ>/l { for(int index=0;index<MAX_KEY;index++){
O'-Zn]@.] if(hCallWnd[index]==NULL)
9+I/y,aC continue;
'c0'P%[5A if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
YeC,@d[ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
eCIRt/ uA //lParam的意义可看MSDN中WM_KEYDOWN部分
npcBpGL{ }
D?}m
h1# }
_qt;{,t }
~f10ZB_k>' return CallNextHookEx( hHook, nCode, wParam, lParam );
\'+{X(] }
9]@J*A}=l f WjS) 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:
`qDz=,)WP P9"D[uz BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
#)A?PO2 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
ckN(`W,xp CS5jJi"pD3 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:
{]\uR-a(o 3Ge <G LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
AKKU-5
B9c {
u45h{i-e if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
o|qeh<2=x {
qH%L"J //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
5u)^FIBj SaveBmp();
{0vbC/?] return FALSE;
V\K
m% vP }
;D"P9b]9$ …… //其它处理及默认处理
V,XP&,no\j }
p
(xD/E _jrA?pY Z"~6yF 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。
uP{+?#a_-\ P}+|`>L 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。
xUo)_P\_ ys[i`~$ 二、编程步骤
|<3Q+EB^ K;y\[2;}e, 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";
OpbT63@L TXD^Do5^ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
%*5g<5 _"!{7e`Z 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;
|t 65#1 :*P___S= 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;
oyN+pFVB:$ ccN &h 5、 添加代码,编译运行程序。
ay:\P.`5) NkA6Cp[Q,1 三、程序代码
h`EH~ W0:z ;;y@z[ > ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
0^!,[oh6* #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
^mgI%_?1 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
R!/,E #if _MSC_VER > 1000
;%rs{XO9 #pragma once
oj^5G
]_< #endif // _MSC_VER > 1000
KSgQ:_u4} #ifndef __AFXWIN_H__
W-C0YU1 #error include 'stdafx.h' before including this file for PCH
[2QY #endif
N}+B:l]Qy #include "resource.h" // main symbols
P96Cw~<Q? class CHookApp : public CWinApp
`z$uw
{
v;bM.OL public:
-Ty<9(~S CHookApp();
EAC(^+15K // Overrides
uF]D // ClassWizard generated virtual function overrides
#>E3' 5b //{{AFX_VIRTUAL(CHookApp)
&Qtp"#{ public:
f=_Bx2ub virtual BOOL InitInstance();
2yJ7]+Jd7Y virtual int ExitInstance();
KtfkE\KP //}}AFX_VIRTUAL
q-3J.VLJ5H //{{AFX_MSG(CHookApp)
nz&b5Xb2 // NOTE - the ClassWizard will add and remove member functions here.
dEQReD // DO NOT EDIT what you see in these blocks of generated code !
|%:qhs, //}}AFX_MSG
)~?S0]j} DECLARE_MESSAGE_MAP()
[al(>Wr9 };
C NzSBm LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
cy& BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
(}*\ { BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
F;?TR[4!k BOOL InitHotkey();
(EOec5qXU BOOL UnInit();
]xJ'oBhy #endif
^Kw&=u ,<;l"v( //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
K4?t' dd] #include "stdafx.h"
JO&;bT< #include "hook.h"
pu2 wEQ #include <windowsx.h>
,);=
(r9 #ifdef _DEBUG
, `[Z`SUk` #define new DEBUG_NEW
Qe @A5# #undef THIS_FILE
=e-a&Ep-z static char THIS_FILE[] = __FILE__;
Ersr\ZB #endif
(sV]UGrZ #define MAX_KEY 100
j#LV7@H.e? #define CTRLBIT 0x04
D y`W5_xSz #define ALTBIT 0x02
B7Ki@) #define SHIFTBIT 0x01
]|C_`,ux #pragma data_seg("shareddata")
1*! c
X HHOOK hHook =NULL;
0,1L e$)6 UINT nHookCount =0;
@wYQLZ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
PEX26== static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
_q$0lqq~u static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
%2@ Tj}xa static int KeyCount =0;
|z!q
r}i static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
Q
QsVIHA #pragma data_seg()
wL8bs-
U HINSTANCE hins;
(1kn): void VerifyWindow();
] 689 Q%D BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
H7z>S G0 //{{AFX_MSG_MAP(CHookApp)
AQnJxIL: // NOTE - the ClassWizard will add and remove mapping macros here.
z&C{8aQ' // DO NOT EDIT what you see in these blocks of generated code!
-(/2_&" //}}AFX_MSG_MAP
3D?IG\3 END_MESSAGE_MAP()
:Bx+WW&P.i dDv{9D, CHookApp::CHookApp()
B&%L`v2[ {
RQj`9F // TODO: add construction code here,
xVsa,EX b // Place all significant initialization in InitInstance
LT,iS)dY+ }
a gmeiJT J+/}K>2# CHookApp theApp;
vCy.CN$ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
XJ
f+Eh {
1V*8,YiC< BOOL bProcessed=FALSE;
hb /8Q if(HC_ACTION==nCode)
h"VpQhi {
hV3,^#9o if((lParam&0xc0000000)==0xc0000000){// Key up
'WKu0Yi^' switch(wParam)
"B|nh d {
dxzvPgi? case VK_MENU:
26\HV MaskBits&=~ALTBIT;
/gqqKUx break;
]Wy^VcqX case VK_CONTROL:
[ -9)T MaskBits&=~CTRLBIT;
V9 +xL 1U# break;
(ZE%tbm2 case VK_SHIFT:
CbTf"pl MaskBits&=~SHIFTBIT;
Qag|nLoT break;
;x!,g5q"q default: //judge the key and send message
Z-4K?;g'k break;
X;s3y{ku }
)^jQkfL for(int index=0;index<MAX_KEY;index++){
iN:G/ss4O if(hCallWnd[index]==NULL)
s0C?Bb}? continue;
'`M#UuU if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
-{yDk$" {
DHh+%|e SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
SBCL1aM bProcessed=TRUE;
_/8_,9H }
|Q5H9<* }
k9*J*7l-m }
ax-=n ( else if((lParam&0xc000ffff)==1){ //Key down
4'+d"Ok switch(wParam)
T4V[RN
{
0=N4O!X9 case VK_MENU:
vbr~<JT= MaskBits|=ALTBIT;
'P@=/ break;
ucQezmie case VK_CONTROL:
G*)s%2c>h MaskBits|=CTRLBIT;
(A7T}znG break;
*)j@G: case VK_SHIFT:
(/T+Wpy? MaskBits|=SHIFTBIT;
XoDJzrL# break;
L/qZ ; { default: //judge the key and send message
tpv?`(DDU break;
#rhVzN-?)W }
2LCc for(int index=0;index<MAX_KEY;index++)
Nbgp_:{ {
$se !8s" if(hCallWnd[index]==NULL)
Y;fuh[# continue;
Am2*- if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
'4af
], {
}U2[? SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
.LX?VD bProcessed=TRUE;
PRMZfYc }
21.YO]Et }
!&@2 }
K&j'c if(!bProcessed){
z`\#$ for(int index=0;index<MAX_KEY;index++){
bcq@N if(hCallWnd[index]==NULL)
-(6eVI continue;
.[edln if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
pO\S#GnX SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
o&CghF }
b cC\ }
l9]o\JFXk }
*Zc9yZl2 return CallNextHookEx( hHook, nCode, wParam, lParam );
Rb{+Ki }
5/Ydv
RB67 aF D="Zh BOOL InitHotkey()
48lzOG {
@; W<dJ<X if(hHook!=NULL){
ceqFQ nHookCount++;
E2>im>p return TRUE;
XZF%0g2$b }
ILNE 4n else
^it4z gx@ hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
=fY lzZh if(hHook!=NULL)
n(Qj||: nHookCount++;
S{o@QVbl return (hHook!=NULL);
.?A'6 }
^/G?QR BOOL UnInit()
8r5xs- {
DG_}9M!DW@ if(nHookCount>1){
jjxIS nHookCount--;
RI?NB6U return TRUE;
#N; $ }
cB{%u
' BOOL unhooked = UnhookWindowsHookEx(hHook);
%rFP#L if(unhooked==TRUE){
}%_qx|(P|t nHookCount=0;
HTxB=Q| hHook=NULL;
O:2 #_ }
Tsu\oJ[ return unhooked;
%wOOzp` }
y@q1c*| QxKAXq@)i BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
[.M {
ty':`) BOOL bAdded=FALSE;
QyTh!QM~` for(int index=0;index<MAX_KEY;index++){
IoQr+:_R if(hCallWnd[index]==0){
yU> T8oFh hCallWnd[index]=hWnd;
'T%IvJ#Xu HotKey[index]=cKey;
O2C6V>Q; HotKeyMask[index]=cMask;
] OUD5T bAdded=TRUE;
$H4=QVj6 KeyCount++;
6KVV z/ break;
ki#y&{v9Be }
K/DH
/
r }
XnD0eua# return bAdded;
5Qb;2! }
%?@x]B9Y8E =1O?jrl~q BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
AD(xaQ&T {
cnbo+U BOOL bRemoved=FALSE;
S
9WawI for(int index=0;index<MAX_KEY;index++){
Lg8]dBXu if(hCallWnd[index]==hWnd){
D4d]3|/T if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
*`%4loW hCallWnd[index]=NULL;
~M*7N@D HotKey[index]=0;
sb'lZFSP~s HotKeyMask[index]=0;
sbzeY1 bRemoved=TRUE;
9-B@GFB;8 KeyCount--;
D^N[=q99&e break;
X@cSP7b }
?b5H
2W }
se!g4XEWD }
}&mj.hGv return bRemoved;
{798=pC<. }
AYt*'Zeg!s ]Uu
aN8 void VerifyWindow()
b"^\)|*4; {
Xp#~N_S$ for(int i=0;i<MAX_KEY;i++){
/GyEV Cc if(hCallWnd
!=NULL){ o94PI*.
if(!IsWindow(hCallWnd)){ >;m{{nj
hCallWnd=NULL; (:JjQ`i
HotKey=0; Ln:lC(
'
HotKeyMask=0; O!/ekU|,r
KeyCount--; ,b$z!dvhl
} Ac
J>$L)
} 1p~5h(jI
} )mj<{Td`
} l4zw]AYk+X
,eDu$8J9
BOOL CHookApp::InitInstance() <H!O:Mf_p
{ {QMN=O&n
AFX_MANAGE_STATE(AfxGetStaticModuleState()); O
3G:0xF
hins=AfxGetInstanceHandle(); WBa /IM
InitHotkey(); xwi!:PAf,o
return CWinApp::InitInstance(); 3<+z46`?
} a`s/ qi
=ydpU<aS
int CHookApp::ExitInstance() <W?WUF
{ 7O"hiDQ
VerifyWindow(); ("b*? : B
UnInit(); /Ad6+cY
return CWinApp::ExitInstance(); v3~FR,Kl
} \PzN XQ$
NfOp=X?Y
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file RFB(d=o5S
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) L(;.n>/
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ .3( ;9};
#if _MSC_VER > 1000 _Cj(fFL
#pragma once mLQUcYfR
#endif // _MSC_VER > 1000 (NPxab8e*
gXF.on4B
class CCaptureDlg : public CDialog / xs9.w8-
{ 7pz\ScSe
// Construction @\!ww/QT
public: (xbIUz.
BOOL bTray; db'K!M)
BOOL bRegistered; y>)MAzz~\
BOOL RegisterHotkey(); eJW[ ] !
UCHAR cKey; 4?
v,wq
UCHAR cMask; ,!hnm
void DeleteIcon(); V+.Q0$~F5
void AddIcon(); \<=IMa0
UINT nCount; &lU Ny
L
void SaveBmp(); RNvQ
CCaptureDlg(CWnd* pParent = NULL); // standard constructor Et.j1M|g
// Dialog Data ~oo'ky*H!
//{{AFX_DATA(CCaptureDlg) J+lGh9G
enum { IDD = IDD_CAPTURE_DIALOG }; sSz%V[XWL
CComboBox m_Key; 86y%=! bS
BOOL m_bControl; I'?6~Sn3
BOOL m_bAlt; =E!x~S;N
BOOL m_bShift; a&N