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:
jO=*:{#x
%4,xx'` 一、实现方法
U2bzUxK qYK4)JP 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:
^00{Hd6 EJ`Q8uz #pragma data_seg("shareddata")
t)} \9^Uo HHOOK hHook =NULL; //钩子句柄
Axlm<3<wf" UINT nHookCount =0; //挂接的程序数目
)Ob]T{GY static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
kae2 73" static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
]BfS270 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
L?8^aG static int KeyCount =0;
%%&e"&7HE static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
s O=4IBE #pragma data_seg()
ll%G!VR Rv<L#!;
t 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。
gXt O*Rfqk KnJx{8@z 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:
3htq[Ren G=|70pxU BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
.#0H{mk cKey,UCHAR cMask)
ox[ .)v {
@.gPJMA BOOL bAdded=FALSE;
-(9O6)Rs$ for(int index=0;index<MAX_KEY;index++){
L6+C]t}>6 if(hCallWnd[index]==0){
V.8%|-d hCallWnd[index]=hWnd;
P`EgA HotKey[index]=cKey;
0 _A23.Y HotKeyMask[index]=cMask;
&cc9}V)M bAdded=TRUE;
(9]6bd KeyCount++;
4z_n4= break;
:H?f*aw }
'w.}2( }
q>-R3HB return bAdded;
r+S;B[Vd }
`*aBRwvK~ //删除热键
;1`!wG-DD BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
=u=Kw R {
?v4E<iXs BOOL bRemoved=FALSE;
{q,?<zBzu for(int index=0;index<MAX_KEY;index++){
1`JB)9P if(hCallWnd[index]==hWnd){
5/?P|T if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
$7NCb7%/L hCallWnd[index]=NULL;
`\N]wlB2/b HotKey[index]=0;
3z3_7XI HotKeyMask[index]=0;
Nqcp1J" bRemoved=TRUE;
#!})3_Qc(y KeyCount--;
%
5z
gd> break;
uv]{1S{tb }
w2OsLi Sv }
l5k?De_(x }
O~PChUU*Y return bRemoved;
% (<(Y }
-bS)=L -Sz_mr gn)R^ DLL中的钩子函数如下:
{DwIjy31T BpH%STEN LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
g
jxS {
yMxTfR BOOL bProcessed=FALSE;
TH4\HY9qa? if(HC_ACTION==nCode)
GeV+/^u {
OJ1tV% E if((lParam&0xc0000000)==0xc0000000){// 有键松开
H0>yi[2f switch(wParam)
m Ni2b*k {
0<.RA%dj case VK_MENU:
,T|x)"uA` MaskBits&=~ALTBIT;
x2W#ROfg break;
(3;@^S4&w case VK_CONTROL:
+Gh7^v|" MaskBits&=~CTRLBIT;
kOjf #@c break;
UyiJU~r1 case VK_SHIFT:
-RMi8{ MaskBits&=~SHIFTBIT;
q0./O|Dj break;
=Op+v" default: //judge the key and send message
"2{%JFE break;
9Ah[rK*} }
;ME)Og for(int index=0;index<MAX_KEY;index++){
tFM$#JN if(hCallWnd[index]==NULL)
Ig \#f continue;
wCCV2tk if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
+Xy*?5E;C {
PsnGXcj SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
sKL:p3r bProcessed=TRUE;
;Ii1B{W }
QDTNx!WL }
+L%IG }
Hd &{d+B else if((lParam&0xc000ffff)==1){ //有键按下
XP3xJm3 switch(wParam)
[L(hG a {
:50b8 case VK_MENU:
?LP9iY${ MaskBits|=ALTBIT;
BRv x[u break;
9 OT,TpA case VK_CONTROL:
Or0O/\D) MaskBits|=CTRLBIT;
c#cx>wq9 break;
T!|=El> case VK_SHIFT:
09h.1/ MaskBits|=SHIFTBIT;
)r tomp:X break;
Vba.uKNjk default: //judge the key and send message
/4irAG% Oj break;
|E)aT#$f' }
=#xK=pRy; for(int index=0;index<MAX_KEY;index++){
o{WyQ&2N if(hCallWnd[index]==NULL)
HM9fjl[ continue;
y2|R.EU\m< if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
y~
rXl {
V
9;[M; SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
@It>*B yB. bProcessed=TRUE;
s:>\/[*>0c }
bPbb\|u0d }
1iBP,:>* }
7h9U{4r: M if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
|j~lkzPnV for(int index=0;index<MAX_KEY;index++){
c&nh>oN if(hCallWnd[index]==NULL)
{XCf-{a]~ continue;
# Su~`] if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
n/4i|-^ SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
t^tmz PWA //lParam的意义可看MSDN中WM_KEYDOWN部分
m#7*:i&@Y }
ec3<%+0f }
b Bc- ^ }
PoSpkJH return CallNextHookEx( hHook, nCode, wParam, lParam );
EnVuD
9 }
&qM[g9 , X{> 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:
/j2H A^GT ??&<k BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
ti @kKz BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
C})'\1O% Wr?'$: 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
/RnTQ4 G&f8n LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
x.mrCJn) {
RP4Ku9hk if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
eD?3"!c! {
2{|$T2?e //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
IH*s8tPc SaveBmp();
x2Lq=zwJ return FALSE;
qoMfSz"( }
"tk-w{> …… //其它处理及默认处理
=n(3o$r( }
0E`1HP"b Ah69
_>N`S #U
mF-c 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。
*iA4:EIP YX*x&5]lq 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。
_QOZsEe EbNd=Z'J 二、编程步骤
E0n6$5Uc? 2/
rt@{V( 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
i]{1^pKq 4'1m4Ugg 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
)FN;+"IJ q!~ -(&S 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
=@x`?oe v x Gk6n4Gg 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
~Heb1tl; rh*sbZ68>E 5、 添加代码,编译运行程序。
*jq7X da!P0x9p 三、程序代码
HeGYu?& PUJ2`iP1^3 ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
d~J-|yyT #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
9p* gU[ #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
&C<yfRDu #if _MSC_VER > 1000
{y= W6uP #pragma once
0fXLcal #endif // _MSC_VER > 1000
^ <`(lyph #ifndef __AFXWIN_H__
yM.IxpT#$ #error include 'stdafx.h' before including this file for PCH
ZzGahtx)Y #endif
+avMX&% #include "resource.h" // main symbols
75T_Dx(H class CHookApp : public CWinApp
Z6C=T;w {
z+}QZ> public:
D1
Z{W CHookApp();
zdl%iop3e // Overrides
Df=dt // ClassWizard generated virtual function overrides
W<ZK,kv //{{AFX_VIRTUAL(CHookApp)
{~GYj%-^ public:
Yj|eji7y virtual BOOL InitInstance();
BAj-akc f virtual int ExitInstance();
( lm&*tKm //}}AFX_VIRTUAL
:,12")N //{{AFX_MSG(CHookApp)
LWoG4s?w // NOTE - the ClassWizard will add and remove member functions here.
%.v{N6 // DO NOT EDIT what you see in these blocks of generated code !
@Hb'8F //}}AFX_MSG
P;[OWSR[d DECLARE_MESSAGE_MAP()
f"u*D,/sS };
`^JJ&)4iv LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
wFh8?Z3u_ BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
`N//A}9 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
%_-zWVJ BOOL InitHotkey();
KOq;jH{$ BOOL UnInit();
]M>9ULQ #endif
g>0XxjP4 [S]S^ej*8 //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
+6$g!S5{ #include "stdafx.h"
`vG,}Pt] #include "hook.h"
n6d9\ #include <windowsx.h>
/^{BUo #ifdef _DEBUG
hVT~~n`Rj #define new DEBUG_NEW
jxaD&4Fs8 #undef THIS_FILE
j:T/ iH!YF static char THIS_FILE[] = __FILE__;
5RH2"*8T #endif
hRI"y":zD #define MAX_KEY 100
N /$`:8" #define CTRLBIT 0x04
1 2++RkL# #define ALTBIT 0x02
GDhE[of #define SHIFTBIT 0x01
}eQRN<}P #pragma data_seg("shareddata")
`(+o=HsD HHOOK hHook =NULL;
.o1^Oh UINT nHookCount =0;
3nZ9m static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
EFuvp8^y static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
>SN|?|2U/ static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
TC~Q
G$NW static int KeyCount =0;
Xv <G-N4 static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
"vYE+ #pragma data_seg()
Md6]R-l@ HINSTANCE hins;
)3YtIH_ void VerifyWindow();
#*$P'r BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
5ercD //{{AFX_MSG_MAP(CHookApp)
/&& 2u7* // NOTE - the ClassWizard will add and remove mapping macros here.
{qW~"z*
// DO NOT EDIT what you see in these blocks of generated code!
f'I z
G.R //}}AFX_MSG_MAP
pMg3fUIM END_MESSAGE_MAP()
l+V,DCE n%R;-?*v CHookApp::CHookApp()
g*)K/Z0pJ$ {
;4M><OS! // TODO: add construction code here,
C3hv* // Place all significant initialization in InitInstance
Xtz-\v#0o' }
IKtB; J89Dul l
CHookApp theApp;
TSAU?r\P LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
Cz4)Yz {
n,eJ$2!J BOOL bProcessed=FALSE;
'\~$dtI$ if(HC_ACTION==nCode)
IKMeJ(:S {
{e|*01hE if((lParam&0xc0000000)==0xc0000000){// Key up
IW8+_#d switch(wParam)
v5;I]?72l~ {
$@d9<83= case VK_MENU:
4Wy<?O2 MaskBits&=~ALTBIT;
QB:i/9 break;
mNf8kwr case VK_CONTROL:
k4qp u=@U MaskBits&=~CTRLBIT;
e__@GBG break;
^JI o?R case VK_SHIFT:
}R3=fbe,\ MaskBits&=~SHIFTBIT;
wxm:7$4C break;
2 oa#0`{ default: //judge the key and send message
,*4p?|A break;
i |{Dd%4vK }
/vY_Y3k# for(int index=0;index<MAX_KEY;index++){
87}&` if(hCallWnd[index]==NULL)
5qg2Zc~ continue;
<9=9b_z if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
t
E` cau {
;!o]wHmA SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
A^ _a3$,0 bProcessed=TRUE;
cJM: }
*Ype>x{ }
]
2DH; }
K.G$]H else if((lParam&0xc000ffff)==1){ //Key down
2^t#6XBk/ switch(wParam)
d=,%=@ {
WwC 5!kZ case VK_MENU:
"#v=IJy&r MaskBits|=ALTBIT;
Cv$
SJc break;
!R*-R.% case VK_CONTROL:
w ;daC(: MaskBits|=CTRLBIT;
T081G`li break;
\MxoZ case VK_SHIFT:
QDpEb=|S MaskBits|=SHIFTBIT;
o7B[R) 4 break;
^:9$@+a default: //judge the key and send message
zkTp`>9R break;
U yw-2]!n }
V{|}}b?w? for(int index=0;index<MAX_KEY;index++)
/8VP[i)u {
Rwr 2gMt7 if(hCallWnd[index]==NULL)
<Sz52Suh> continue;
5XuT={o if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
b{fQ|QD{^E {
0-LpqX SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
C^QtSha bProcessed=TRUE;
,!V]jP) }
b 1&i# I?{ }
"<}&GcJbz }
Z%GTnG|rG if(!bProcessed){
1!pa;$L for(int index=0;index<MAX_KEY;index++){
2+Px'U\ if(hCallWnd[index]==NULL)
<foCb%$(? continue;
LqdY Qd51 if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Soie^$
Y SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
iHf-{[[Z }
}F+zs*S }
0l;<5 }
6t/`:OZC: return CallNextHookEx( hHook, nCode, wParam, lParam );
`%3/ }
9N%JP+<89 JQ:Ri BOOL InitHotkey()
o]IjK {
4tSv{B/} if(hHook!=NULL){
2<mW\$ nHookCount++;
rF\"w0J_ return TRUE;
_C\[DR0n }
i{D=l7j|w else
RE.r4uOJg hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
n.hv!W0 if(hHook!=NULL)
UpXz&k nHookCount++;
8q`$y$06Dk return (hHook!=NULL);
FgL,k }
aA- BOOL UnInit()
U/lM\3v/e {
(M
=Y&M'f if(nHookCount>1){
L6>pGx nHookCount--;
$D31Q[p=+ return TRUE;
?PTk1sB }
,@m@S^ BOOL unhooked = UnhookWindowsHookEx(hHook);
(Qgde6 if(unhooked==TRUE){
l{w#H|] nHookCount=0;
,ZblIOWb hHook=NULL;
%+ZJhHT }
VF&Z%O3n return unhooked;
EBtLzbj }
3D9!M- MxzLK%am BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
%AOIKK5 {
iR$<$P5 BOOL bAdded=FALSE;
b;|55Y for(int index=0;index<MAX_KEY;index++){
-T6(hT\ if(hCallWnd[index]==0){
gPC*b+ hCallWnd[index]=hWnd;
}HEvr)v9 HotKey[index]=cKey;
~.%K/=wK @ HotKeyMask[index]=cMask;
*&AfR8x_z bAdded=TRUE;
kP xa7 KeyCount++;
Y32O-I!9u break;
"^I
mb, }
jkiTj~WE- }
:V)lbn\ return bAdded;
XWJwJ }
?muzU.h"z C@N1ljXJT BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
OL7_'2_z. {
;M]C1!D9# BOOL bRemoved=FALSE;
;X ,1I for(int index=0;index<MAX_KEY;index++){
{b]aC if(hCallWnd[index]==hWnd){
9;yn}\N ` if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
.kTG[)F0b hCallWnd[index]=NULL;
[<`SfE HotKey[index]=0;
-st7_3 HotKeyMask[index]=0;
yBLK$@9 bRemoved=TRUE;
B7\k< Nit0 KeyCount--;
*`(
<'Z break;
wOB azWa }
Cw5%\K$= }
bYe;b><G }
W~_t~Vg5 return bRemoved;
~f|Z%&l| }
uH3D{4 s=?aox7 void VerifyWindow()
K!D
o8| {
<"o"z2 for(int i=0;i<MAX_KEY;i++){
X\p,%hk \ if(hCallWnd
!=NULL){ zb6ju]2
if(!IsWindow(hCallWnd)){ W:i?t8y\y
hCallWnd=NULL; H1!iP$1#V
HotKey=0; =O|c-k,f@
HotKeyMask=0; ,_!6U
KeyCount--; \qi|Js*{
} ,?
E&V_5
} VC5_v62&.
} wwKh CmH
} uGdp@]z&8Q
\Mv":Lm1
BOOL CHookApp::InitInstance()
Lw1T 4n
{ v+6@cC
AFX_MANAGE_STATE(AfxGetStaticModuleState()); PR<||"03
hins=AfxGetInstanceHandle(); T5wjU*=IL
InitHotkey(); 7dihVvL
$
return CWinApp::InitInstance(); >k']T/%
} (Lh#`L?x
v;{{ y-
int CHookApp::ExitInstance() 7iuQ9q^&
{ 9Qj2W
VerifyWindow(); v"+k~:t*
UnInit(); NV4g~ +n
return CWinApp::ExitInstance(); Ql?^
B
SqG
} iq?#rb P#I
FDR1Gy
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file *cWmS\h|
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) 3*DXE9gA9
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ {>0V[c[~
#if _MSC_VER > 1000 R)!`JKeO/
#pragma once <