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:
T\w{&3ONm
Ogu";p( 一、实现方法
#+L:V&QE YK>?;U+| 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:
Xx1e SX rIeOli:< #pragma data_seg("shareddata")
g17 fge6% HHOOK hHook =NULL; //钩子句柄
[Gc9
3PA7q UINT nHookCount =0; //挂接的程序数目
6e%ZNw{#= static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
m1Xc3=Y static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
Ie(M9QMp static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
J+m1d\lBu static int KeyCount =0;
Xa$-Sx static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
`]F#j ]" #pragma data_seg()
RMlx[nsq #|K5ma 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。
ht2J, 1t ,:8oVq>? 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:
B-h@\y soh9Oedml- BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
O% 8>siU cKey,UCHAR cMask)
L:7 kp<E {
u1`JvfLrL BOOL bAdded=FALSE;
lX64IvG8+o for(int index=0;index<MAX_KEY;index++){
t'[`"pp= if(hCallWnd[index]==0){
F#a'N c9 hCallWnd[index]=hWnd;
h/]));p HotKey[index]=cKey;
$Y[C A.F HotKeyMask[index]=cMask;
PAXm bAdded=TRUE;
6*:U1{Gl) KeyCount++;
4e?MthJ> break;
|%@pjJ`3 }
03gYl0B }
FiKGB\_] return bAdded;
Bz?
(?fyd }
O+t'E9Fa //删除热键
{J-Ojw|Y b BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
-nY_.fp> {
NmTo/5s BOOL bRemoved=FALSE;
8;O /x for(int index=0;index<MAX_KEY;index++){
\7G.anY if(hCallWnd[index]==hWnd){
0+NGFX\p if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
d$y?py hCallWnd[index]=NULL;
g/gaPc*86 HotKey[index]=0;
p21li}Iu HotKeyMask[index]=0;
B? 9"Ztb bRemoved=TRUE;
5ljEh - KeyCount--;
uP.dCs9- break;
3x>Y }
m2[J5n?zLL }
?N&s. }
i<*W,D6
return bRemoved;
n$<n
Yr`X }
aVp-Ps|r jXIVR'n( r |2{(+ DLL中的钩子函数如下:
Gm=e;X;r XO}SPf- LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
]>[0DX]j {
Se>v|6 BOOL bProcessed=FALSE;
UL"
M?).5 if(HC_ACTION==nCode)
]3uj~la {
G4uA&"OE if((lParam&0xc0000000)==0xc0000000){// 有键松开
gSkY c{b switch(wParam)
V5p->X2# {
j|LO g case VK_MENU:
&}d5'IRT MaskBits&=~ALTBIT;
`Dp4Z>|
K break;
W&7( case VK_CONTROL:
WQMoAPfqL MaskBits&=~CTRLBIT;
)1f.=QZN^; break;
S2EV[K8# case VK_SHIFT:
x[mh^V5ld MaskBits&=~SHIFTBIT;
L$ZsNs+ break;
9[h8Dy default: //judge the key and send message
UTqKL*p523 break;
on
4
$n7 }
|{La@X for(int index=0;index<MAX_KEY;index++){
ON"p^o>/_? if(hCallWnd[index]==NULL)
zpg512\y continue;
zICrp if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
S 9;FD 3 {
wpt5'|I SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
#wJ^:r-c` bProcessed=TRUE;
@{ L|&Mk! }
\_7'f }
umt(e:3f5 }
le6eorK8 else if((lParam&0xc000ffff)==1){ //有键按下
|}@teN^J*U switch(wParam)
y:k7eE" {
/sSM<r]5j case VK_MENU:
n!U1cB{ MaskBits|=ALTBIT;
B/B`=%~5_^ break;
" s/ws case VK_CONTROL:
Y6a9S`o MaskBits|=CTRLBIT;
CKX3t:HP0 break;
yF-`f
_ case VK_SHIFT:
Rp>%umDyL MaskBits|=SHIFTBIT;
P`y.3aK break;
KBA&s default: //judge the key and send message
D4*_/,} break;
OX [r\ }
<&HHo>rl for(int index=0;index<MAX_KEY;index++){
<2wC)l3j* if(hCallWnd[index]==NULL)
.f|)od[ continue;
7gREcL2 if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
\)W Z D {
cDz^jC SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
/1eeNbd bProcessed=TRUE;
r+tHVh }
WUb] 8$n }
{&J
OO }
0Kg?X if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
&td for(int index=0;index<MAX_KEY;index++){
.>2]m[53 if(hCallWnd[index]==NULL)
:W$-b continue;
3~Ll<8fv if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
fM"&=X SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
m@YK8c#$ //lParam的意义可看MSDN中WM_KEYDOWN部分
hJ75(I
*j }
UDPn4q }
9{Igw"9ck }
'ZAIe7i& return CallNextHookEx( hHook, nCode, wParam, lParam );
[J55%N;#1 }
GQ sE5Vb ssl.Y! 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:
o* e'D7 rx@2Dmt6
BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
s%G%s,d BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
YR[I,j |Z8Eu0RSb 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:
N(P2Lo{JF =&m;5R
LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
D$VRE^k {
R`,|08E if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
li0)<("/ {
D58RHgY[ //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
CtZOIx.;| SaveBmp();
w"L]?# return FALSE;
>` u8( }
xl9S=^`= …… //其它处理及默认处理
AuY*x;~ }
.UvDew/Y N$u: ! V5gr-^E 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。
@?gRWH;Pq 3E}j*lo 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。
9<o*aFgCa Z6&bUZF$bE 二、编程步骤
WA.c.{w\
j} w 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
5Ha(i [d w*X(bua@ 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
bm h@SB #"C!-kS'= 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
@.,'A[D!K 2'Raj'2S4 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
Q]OR0-6<. 2nCHL'8N 5、 添加代码,编译运行程序。
2>f3nW qCq?`0&# 三、程序代码
(3=bKcD' <- R% ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
# wyjb:Ql #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
SZ:R~4 A #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
<[=[|DS l #if _MSC_VER > 1000
r]Lj@0F>8 #pragma once
)JU`Z@?8 #endif // _MSC_VER > 1000
JURg=r]LI #ifndef __AFXWIN_H__
vzF6e eaD #error include 'stdafx.h' before including this file for PCH
M0hR]4T #endif
,V''?@ #include "resource.h" // main symbols
NOf{Xx<#k class CHookApp : public CWinApp
~+PK Ws'}F {
=FMrVE public:
,+x\NY2d CHookApp();
HUbXJsSP // Overrides
G0Z$p6z // ClassWizard generated virtual function overrides
Ga`
8oY+~ //{{AFX_VIRTUAL(CHookApp)
y^ D3}ds public:
iZ0(a virtual BOOL InitInstance();
h]4qJ virtual int ExitInstance();
"$q"Kilj% //}}AFX_VIRTUAL
4-9cp=\PE //{{AFX_MSG(CHookApp)
;zSV~G6- // NOTE - the ClassWizard will add and remove member functions here.
ClufP6' // DO NOT EDIT what you see in these blocks of generated code !
ca[*#xiJ //}}AFX_MSG
COd~H DECLARE_MESSAGE_MAP()
ssmJ?sl };
a, `B.I LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
9e&*++vf BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
9h<iw\$' BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
"V,dH%&j BOOL InitHotkey();
h}}7_I9 BOOL UnInit();
QRF:6bAxsL #endif
G#='*vOtO &m{~4]qWpM //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
[p)2!]y #include "stdafx.h"
:4pO/I
~ #include "hook.h"
!H @nAz #include <windowsx.h>
Rb
<{o8 #ifdef _DEBUG
p4K
8L'nZ #define new DEBUG_NEW
5KssfI
a #undef THIS_FILE
g}vU*g
; static char THIS_FILE[] = __FILE__;
qLB(Th\&' #endif
oJI+c+e" #define MAX_KEY 100
l_fERp#y #define CTRLBIT 0x04
+ Cq&~<B #define ALTBIT 0x02
w_Z*X5u #define SHIFTBIT 0x01
x
o72JJ #pragma data_seg("shareddata")
/!y3ZzL HHOOK hHook =NULL;
Tn$|
Xa+:s UINT nHookCount =0;
],wzZhA static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
x6|QTO static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
y|WOw(# static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
aQ)g7C static int KeyCount =0;
<"S/M]9 static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
p+{*w7?8"[ #pragma data_seg()
?\a';@h HINSTANCE hins;
MO79FNH2\ void VerifyWindow();
oXqx]@7 BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
jLBwPI_g //{{AFX_MSG_MAP(CHookApp)
3zp)!QJi // NOTE - the ClassWizard will add and remove mapping macros here.
!v<r=u // DO NOT EDIT what you see in these blocks of generated code!
abuHu'73 //}}AFX_MSG_MAP
z9U<Z^4z+ END_MESSAGE_MAP()
NQ !t ` gfw,S; CHookApp::CHookApp()
+|).dm {
R8F[
7&( // TODO: add construction code here,
!m^;Apuy // Place all significant initialization in InitInstance
N?U;G*G }
~;QO`I=0P 1Z6<W~,1OM CHookApp theApp;
=\AI92 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
$GNN*WmHw {
)7Gm<r BOOL bProcessed=FALSE;
SN(:\|f
2 if(HC_ACTION==nCode)
]C3{ _?= {
&Vg+n0 if((lParam&0xc0000000)==0xc0000000){// Key up
m{x[q switch(wParam)
v*<hE>J0 {
E#v}// case VK_MENU:
O&V}T#8n MaskBits&=~ALTBIT;
/jaTH_Q),: break;
CO%7^}xSE, case VK_CONTROL:
b4ZZyw MaskBits&=~CTRLBIT;
4Pe%*WTX break;
X#'DS&{ case VK_SHIFT:
*%7 [{Loz MaskBits&=~SHIFTBIT;
O
$'#8 break;
)o;/*h%@ default: //judge the key and send message
jB!p,fqcb break;
>0DQ<@ot: }
!?Gt5$f for(int index=0;index<MAX_KEY;index++){
\ ,ARYwd if(hCallWnd[index]==NULL)
BCYTlxC' continue;
Q[ kbEhv; if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
9Bvi2
3 {
7n9&@D3:P SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
_VGAh:v bProcessed=TRUE;
z0+LD }
f6vhW66:?x }
}(A`aB_ }
8=CdO|XV else if((lParam&0xc000ffff)==1){ //Key down
Q^prHn*@ switch(wParam)
>lQ@" U {
83K)j"!<X case VK_MENU:
4~xKW2*`K MaskBits|=ALTBIT;
:7UC=GKQk break;
h/ 5|3 case VK_CONTROL:
o}$uP5M8q MaskBits|=CTRLBIT;
{L~j;p_G& break;
p.6C.2q~s] case VK_SHIFT:
@W6:JO MaskBits|=SHIFTBIT;
)12.W=p break;
39to5s, default: //judge the key and send message
G%^jgr) break;
L#O1> }
\ne1Xu:hM for(int index=0;index<MAX_KEY;index++)
5{Q5?M] {
${m;x: ' if(hCallWnd[index]==NULL)
lC/1,Z/M continue;
60,z! Vv if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
)Tjh
{
*/c4b:s SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
K8#MQR2@ bProcessed=TRUE;
WX
.Ax$fT }
W*S}^6ZT` }
yN[aBYJx,M }
oCfO:7 if(!bProcessed){
YBh|\ for(int index=0;index<MAX_KEY;index++){
Y`F) UwKK if(hCallWnd[index]==NULL)
b S-o86u continue;
/T_{k. if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
ICck 0S! SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
/2^"c+/'p }
:I_p4S.) }
qm^|7m^ }
,w`g+ 9v return CallNextHookEx( hHook, nCode, wParam, lParam );
pwvzs`[; }
4Vtug> Hjhgu= BOOL InitHotkey()
V>Dqw! {
5aj%<r if(hHook!=NULL){
:eIi^K z[ nHookCount++;
Hg&.U;n return TRUE;
/H4Z.|@ }
c wNJ{S+ else
:HW| mqKd hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
nuKcq!L if(hHook!=NULL)
rn^cajO^ nHookCount++;
b?{MXJ| return (hHook!=NULL);
wE[gp+X~ }
n6AA%? 5 BOOL UnInit()
KH$|wv {
E5aRTDLq if(nHookCount>1){
(E;+E\E nHookCount--;
@C-03`JWuK return TRUE;
@E 8P>kq }
rjffpU BOOL unhooked = UnhookWindowsHookEx(hHook);
<%o9*)F if(unhooked==TRUE){
rJZR8bo nHookCount=0;
44NMof8N hHook=NULL;
ho-#Xbq#g }
_9g-D9 return unhooked;
e2e!"kEF }
Zg$S% 1(Q KomMzG: BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
3. @LAF {
/oW]? 9 BOOL bAdded=FALSE;
76bMy4re for(int index=0;index<MAX_KEY;index++){
|h}4J if(hCallWnd[index]==0){
_RzFh hCallWnd[index]=hWnd;
dQ:F 5|p HotKey[index]=cKey;
D Qz+t HotKeyMask[index]=cMask;
%ufh bAdded=TRUE;
w
>2sr^!y KeyCount++;
.uVd' break;
=n5n }
|_+#&x }
d)S`.Q return bAdded;
aZ$5" }
BPa,P_6( ?m5EXe BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
;W+8X-B {
9Vqy<7i1 BOOL bRemoved=FALSE;
'da
'WZG for(int index=0;index<MAX_KEY;index++){
(8aj`> y if(hCallWnd[index]==hWnd){
&&m3E=K!^ if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
,cL;,YN hCallWnd[index]=NULL;
]+46r!r| HotKey[index]=0;
D
HT^.UM28 HotKeyMask[index]=0;
g0bYO!gCr bRemoved=TRUE;
6F!B*lr KeyCount--;
t/Y0e#9, break;
4xEw2F }
a/\{NHs6"5 }
$%q=tn'EX }
:^Pks R return bRemoved;
zxx\jpBBk }
CxeW5qc JC%&d1
void VerifyWindow()
u1L^INo/ {
uf90 for(int i=0;i<MAX_KEY;i++){
ghWWJx9 if(hCallWnd
!=NULL){ :u./"[G
if(!IsWindow(hCallWnd)){ ^t5My[R
hCallWnd=NULL; V0v,s^\H
HotKey=0; 6_4B!
HotKeyMask=0; F'b%D
KeyCount--; !}z'"l4i
} <|4$TH^t
} l@Vv%w9H
} K\rQb
} IO)#O<
s91[@rh/
BOOL CHookApp::InitInstance() P2a5<#_|
{ NDP"
@
AFX_MANAGE_STATE(AfxGetStaticModuleState()); '1:) q
hins=AfxGetInstanceHandle();
k[D_L`
InitHotkey(); d]]z )
return CWinApp::InitInstance(); )^ Y+Vn
} VFL^-tXnA^
0SQr%:zG
int CHookApp::ExitInstance() x{SlJ%V
{ [&