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:
TTNkr`
E|"=.
T 一、实现方法
=H7xD"'%R `rY2up#% 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:
)n7l'}o?+ )YW<" $s #pragma data_seg("shareddata")
79J-)e9 HHOOK hHook =NULL; //钩子句柄
92W&x' UINT nHookCount =0; //挂接的程序数目
DLE8+NV8
static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
vy@rQC %9 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
WUdKLx%F static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
e=P static int KeyCount =0;
J a,d3K
static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
r~[vaQQ6L #pragma data_seg()
m,LG=s ig"uXs 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
d=.2@Ry 3Q}$fQ&S 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:
!,$i6gm ^u)z{.z'H/ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
qf'm=efRyu cKey,UCHAR cMask)
5@osnf? {
{WN(&eax BOOL bAdded=FALSE;
-!qu"A: for(int index=0;index<MAX_KEY;index++){
w6|9|f/ if(hCallWnd[index]==0){
XP[uF ;w hCallWnd[index]=hWnd;
K5Wg"^AHY/ HotKey[index]=cKey;
1tzV8(7 HotKeyMask[index]=cMask;
u }hF8eD bAdded=TRUE;
,M !tm7 KeyCount++;
G*
%t'jX9 break;
wl=61Mb }
tEd.'D8 s }
sf}Dh return bAdded;
%u{W7 }
JD>d\z2QC //删除热键
igf)Hb;5 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
Ha>*?`?yI {
$Byj}^ ;1 BOOL bRemoved=FALSE;
iSRpfU for(int index=0;index<MAX_KEY;index++){
&tR(n$M@> if(hCallWnd[index]==hWnd){
jPvDFT^d/ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
td2/9|Q hCallWnd[index]=NULL;
w-B^
[< HotKey[index]=0;
R HotKeyMask[index]=0;
u?ek|%Ok bRemoved=TRUE;
8Chj
w wB KeyCount--;
!4@G3Ae22 break;
#4LFG\s }
Huw\&E }
0x2!<z }
Zx }&c |Q return bRemoved;
Z]w#vLR }
vQV K$n` bte~c {'+QH)w( DLL中的钩子函数如下:
fpyz' qr\!*\9 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
I<b?vR 'F {
VvbFp BOOL bProcessed=FALSE;
MWk:sBCqr if(HC_ACTION==nCode)
+eX)48 {
| aQ"3d if((lParam&0xc0000000)==0xc0000000){// 有键松开
EUYCcL'G switch(wParam)
1xJ
TWWj- {
Gm`}(;(A case VK_MENU:
TOF
'2&H MaskBits&=~ALTBIT;
vh!v
MB}} break;
NIr@R7MKd case VK_CONTROL:
k`HP"H MaskBits&=~CTRLBIT;
`[#x_<\t break;
:m=m}3/: case VK_SHIFT:
OIHz I2{ MaskBits&=~SHIFTBIT;
u]^N&2UW break;
[mxTa\ default: //judge the key and send message
Dz=k7zRg" break;
Rr(* aC2P }
(oK^c-x for(int index=0;index<MAX_KEY;index++){
iyZZ}M if(hCallWnd[index]==NULL)
ylf[/='0K continue;
kyh_9K1 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
u
D 5%E7 {
ulHn#) SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
8 S`9dSc bProcessed=TRUE;
3Rg}+[b
}
fyz
nuUl }
/NT[ETMk+ }
@(``:)Z<b else if((lParam&0xc000ffff)==1){ //有键按下
*MNHT`Y^o switch(wParam)
a>4uiFiv {
2g*J case VK_MENU:
'J*<iA*W MaskBits|=ALTBIT;
BIaDY<j90 break;
h.rD}N\L case VK_CONTROL:
~sQjl] MaskBits|=CTRLBIT;
?zJpD8e break;
fqz28aHh case VK_SHIFT:
C`rLj5E% MaskBits|=SHIFTBIT;
Oh.ZPG= break;
*x~xWg9^ default: //judge the key and send message
/il@`w;G break;
#yseiVm; }
(LvS
:?T} for(int index=0;index<MAX_KEY;index++){
iVtl72O if(hCallWnd[index]==NULL)
2s*#u<I continue;
{cK^,?x if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
}y%`)lz~ ; {
:H6FPV78 SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
+1C3`0( bProcessed=TRUE;
wyx(FinIH }
"Y`3DxXz }
T[k4lM }
C;AA/4Ib if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
_s,ao'/ for(int index=0;index<MAX_KEY;index++){
:_<_[Y]1 if(hCallWnd[index]==NULL)
ukgAI<O% continue;
zHWSE7! if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
?B@;QjhjiJ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
mN`YuR~ //lParam的意义可看MSDN中WM_KEYDOWN部分
i[C~5}% }
'PZ|:9FX! }
e[u?_h }
{",MCu_V return CallNextHookEx( hHook, nCode, wParam, lParam );
yAT^VRbv }
{s?M*_{| 14eW4~Mr 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:
os3 8u!3- CD j~;$[B BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
)'4P.>!!aQ BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
rsn.4P= (w( 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:
%U7.7dSOI; -b&{+= ^c LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
v7 {
}/dRU${! if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
ubsSa}$q {
#BVtL :x@ //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
I:&/`K4,x, SaveBmp();
R9We/FhOY return FALSE;
U=Y)V% }
1[F3 Z …… //其它处理及默认处理
a`9L,8Ve }
?rVy2! F~#zxwd 6dH }]~a 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。
h!@|RW&}qX <^.=>Q0S\ 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。
}_tl n `cz2DR-" 二、编程步骤
j*@l"V>~ [sV"ws 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";
2Q7R6*<N: <F7kh[L_x 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
<`X"}I3ba t9
\x%=
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;
"eWk#/
@4d)R 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;
i!2TH~zl oeSN9O 5、 添加代码,编译运行程序。
zQ?!f#f 'mCe=Y 三、程序代码
WFR?fDtE ^VW
PdH/Fe ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
$w)~O<_U #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
TlL^7f} #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
C,V%B #if _MSC_VER > 1000
1sE?YJP- #pragma once
O-]mebTvw #endif // _MSC_VER > 1000
qs\2Z@; #ifndef __AFXWIN_H__
!J1rRPV #error include 'stdafx.h' before including this file for PCH
_cTh#t ^ #endif
'oNO-)p\#! #include "resource.h" // main symbols
DBLk!~IF class CHookApp : public CWinApp
*,C(\!b
!? {
_$NIp `d public:
q>f<u& CHookApp();
(z7vl~D // Overrides
r0t^g9K0 // ClassWizard generated virtual function overrides
#
?1Sm/5k` //{{AFX_VIRTUAL(CHookApp)
$CTSnlPq public:
*b *G2f^ virtual BOOL InitInstance();
e+v({^k virtual int ExitInstance();
n8=5-7UT //}}AFX_VIRTUAL
# ,uya2!) //{{AFX_MSG(CHookApp)
m p<1yY] // NOTE - the ClassWizard will add and remove member functions here.
<99M@ cF // DO NOT EDIT what you see in these blocks of generated code !
]Y6cwZOe //}}AFX_MSG
-m'j]1 DECLARE_MESSAGE_MAP()
^2d!*W| };
AT2v!mNyCw LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
%:>3n8n BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
{^CT}\=> BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
hc
(e$## BOOL InitHotkey();
0.$hn BOOL UnInit();
Rtb :nJ8 #endif
v}@xlB= M7f;Pa //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
#ywk|k5z] #include "stdafx.h"
M)*\a/6?{ #include "hook.h"
6-`|:[Q~ #include <windowsx.h>
QY/hI` #ifdef _DEBUG
DU%w1+u #define new DEBUG_NEW
1}hIW":3Sr #undef THIS_FILE
4%WzIzRb static char THIS_FILE[] = __FILE__;
~/NKw: #endif
ZZQG?("S' #define MAX_KEY 100
YDC mI@ #define CTRLBIT 0x04
f~E*Zz`; #define ALTBIT 0x02
{NpM.; #define SHIFTBIT 0x01
_0+0#! J! #pragma data_seg("shareddata")
6s,uXn HHOOK hHook =NULL;
^@P1
JNe UINT nHookCount =0;
x@mL $ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
f)]%.> static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
AV 8n( static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
_'4A|-9 static int KeyCount =0;
NmK8<9`u static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
01!s"wjf #pragma data_seg()
V)Z70J<' HINSTANCE hins;
d]9U^iy void VerifyWindow();
Iff9'TE BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
'65LKD //{{AFX_MSG_MAP(CHookApp)
~HQ9i%exg // NOTE - the ClassWizard will add and remove mapping macros here.
ntNI]~z& // DO NOT EDIT what you see in these blocks of generated code!
R1&unm0 //}}AFX_MSG_MAP
f= >OJ!: END_MESSAGE_MAP()
1+b{}d '|;X0fD CHookApp::CHookApp()
=b;>?dP {
y@CHR // TODO: add construction code here,
Y*_)h\f // Place all significant initialization in InitInstance
'B+ ' (f }
u3Gjg{-N7 $R<Me CHookApp theApp;
nRd)++ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
4|A>b})H {
zByT$P- BOOL bProcessed=FALSE;
ceNix!P if(HC_ACTION==nCode)
B^).BQ {
aq7~QX_0G if((lParam&0xc0000000)==0xc0000000){// Key up
"3FihE]k switch(wParam)
5s(1[( {
$mF_,| case VK_MENU:
"~TA SX_? MaskBits&=~ALTBIT;
?` SUQm break;
c8Z wr]DF case VK_CONTROL:
vb9OonE2 MaskBits&=~CTRLBIT;
E2)h?cs break;
hsu{ey p case VK_SHIFT:
fnx-s{c? MaskBits&=~SHIFTBIT;
q7u'_R,; break;
UMX@7a,[3 default: //judge the key and send message
Z{'i F break;
tTd\| }
X.`~>`8 for(int index=0;index<MAX_KEY;index++){
!3T&4t if(hCallWnd[index]==NULL)
x@8a'' continue;
KZ~*Nz+H2 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
R$zH] {
f6$b
s+oP SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
q -8t'7 bProcessed=TRUE;
3Hf0MAt }
iR"N13 }
;c$ J=h] }
.k,YlFvj else if((lParam&0xc000ffff)==1){ //Key down
O|_h_I-2 switch(wParam)
C]Q8:6b {
^*fQX1h< case VK_MENU:
FVhU^ MaskBits|=ALTBIT;
I%urz!CNE* break;
Q_l'o3 case VK_CONTROL:
}-~l!
MaskBits|=CTRLBIT;
s&'QN=A break;
\W1/p` case VK_SHIFT:
[9:9Ql_h MaskBits|=SHIFTBIT;
a&vY!vx3 break;
4tY ss default: //judge the key and send message
W`^@)|9^) break;
E!S 78z: }
nS>8bub30 for(int index=0;index<MAX_KEY;index++)
[$[:"N_ {
*hcYGLx
r if(hCallWnd[index]==NULL)
cu+FM continue;
m.,U:> if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
I!^O)4QRx {
fFQ|T:vm SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
[`
sL?&a bProcessed=TRUE;
#:SNHM^>< }
4`,j =3 }
Dc)dE2 }
s.8{5jVG if(!bProcessed){
:6%Z]tt for(int index=0;index<MAX_KEY;index++){
B7imV@< if(hCallWnd[index]==NULL)
s&j-\bOic9 continue;
=hl }.p if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
v$^Z6>vVI SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
NO :a; }
rx}r~0i }
GgKEP,O }
)p*}e8L return CallNextHookEx( hHook, nCode, wParam, lParam );
.1LCXW= }
$8BPlqBIZ i~r l o^ BOOL InitHotkey()
z;y:9l {
3po:xMY if(hHook!=NULL){
IsR!'%Pu nHookCount++;
!W?gR.0$= return TRUE;
Kv~U6_=1O }
XC+A_"w) else
S{3nM< hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
JfPD}w if(hHook!=NULL)
G}p\8Q}' nHookCount++;
'F3)9&M return (hHook!=NULL);
qgrg CJ }
vx4+QQYP BOOL UnInit()
mkR2i> {
&4_qF^9J if(nHookCount>1){
i&n'N8D@ nHookCount--;
/t(C>$ }p return TRUE;
&iV{:)L }
dUsxvho BOOL unhooked = UnhookWindowsHookEx(hHook);
h yv2SxP* if(unhooked==TRUE){
2PG [7u^ nHookCount=0;
"Iix
)Ue hHook=NULL;
g&{9VK6. }
=z8f]/k*> return unhooked;
i7ly[6{^pr }
VH:]@x//{ yDGVrc' BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
GAAm0; {
{^N[("` BOOL bAdded=FALSE;
P67o{EdK for(int index=0;index<MAX_KEY;index++){
5scEc,JCi if(hCallWnd[index]==0){
AoyX\iqQ hCallWnd[index]=hWnd;
$.bBFWk HotKey[index]=cKey;
9H%X2#:fH HotKeyMask[index]=cMask;
h;0S%ZC bAdded=TRUE;
+U@<\kIF KeyCount++;
ZzX~&95G break;
n?c]M }
&