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:
8
1KG1i )
1|EU5< 一、实现方法
-m'3L7: jdg
~!<C 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:
Nzi/3r7m R3{*v =ov #pragma data_seg("shareddata")
[mB(GL HHOOK hHook =NULL; //钩子句柄
rxgVT4 UINT nHookCount =0; //挂接的程序数目
tY$ty0y-e static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
]k`Fl," static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
4'{hI;&a& static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
3^A/`8R7K static int KeyCount =0;
,F?~'-K static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
28Ssb| #pragma data_seg()
;x3 ]4^ J<($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。
nhQ44qRgQ AeY$.b DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
Bsu=^z ! F;<xgw BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
=wlm cKey,UCHAR cMask)
o9T@uWh+ {
cdJ`Gk BOOL bAdded=FALSE;
(@WDvgi( for(int index=0;index<MAX_KEY;index++){
8MeO U if(hCallWnd[index]==0){
.i3lG(
YG hCallWnd[index]=hWnd;
6h:?u4 HotKey[index]=cKey;
Ql:
b1C, HotKeyMask[index]=cMask;
/ 8WpX bAdded=TRUE;
DUuC3^R KeyCount++;
{glqWFT break;
2iR:*}5 }
tJh3$K\ }
v/aPiFlw return bAdded;
KT
lP:pB; }
*m| t=9E //删除热键
ph8Jn+|E BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
|>IUtUg\ {
0?6If+AC BOOL bRemoved=FALSE;
:?$Sb8OuIL for(int index=0;index<MAX_KEY;index++){
){:q;E]^fB if(hCallWnd[index]==hWnd){
/H%<oAjp6 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
3I;xU(rv hCallWnd[index]=NULL;
a* W_fxb HotKey[index]=0;
%<=w [*i HotKeyMask[index]=0;
.o\;,l2 bRemoved=TRUE;
\`P2Yq KeyCount--;
clq~ ;hx break;
DYT@BiW{ }
M}=s3[d(, }
#7-kL7 MK] }
\8> return bRemoved;
0\EpH[m}- }
bRK CY6 wuBlFUSg z<yNG/M1>U DLL中的钩子函数如下:
e>?_)B4 v9t47>V LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
^)9MzD^_nV {
"RV`L[(P*k BOOL bProcessed=FALSE;
}&Wp3EWw if(HC_ACTION==nCode)
|8DH4*y! {
Z^'?|qFj! if((lParam&0xc0000000)==0xc0000000){// 有键松开
)KaLSL> switch(wParam)
wVvqw/j*f {
P7'oXtW{o case VK_MENU:
KrdZEi vb MaskBits&=~ALTBIT;
}@rg5$W break;
9S:{ case VK_CONTROL:
dN]Zs9] MaskBits&=~CTRLBIT;
inr%XS/m break;
(C-,ljY case VK_SHIFT:
DD12pL{QA MaskBits&=~SHIFTBIT;
zz(!t eBC break;
2~G,Ia default: //judge the key and send message
X
zi'Lu` break;
$zk^yumdE }
L,Ao.?j for(int index=0;index<MAX_KEY;index++){
{h/OnBwG if(hCallWnd[index]==NULL)
%XEKhy continue;
0On?{Bw if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
qYgwyj=4 {
kfMhw M8kP SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
QHHW(InG< bProcessed=TRUE;
ZdE>C }
a)3O? Y }
Vl5SL{+D }
_o@(wGeu# else if((lParam&0xc000ffff)==1){ //有键按下
G$?|S@I, switch(wParam)
4zo4H~@gk {
~q0I7M case VK_MENU:
[,OJX
N-4s MaskBits|=ALTBIT;
W]@gQ(Ef break;
'GEBxNH: case VK_CONTROL:
;;EDN45 MaskBits|=CTRLBIT;
wF|0n t break;
Yw$a{5g case VK_SHIFT:
{l&Ltruhz MaskBits|=SHIFTBIT;
l^DINZU@ break;
(Oxz'#TX default: //judge the key and send message
A[u)wX^`f^ break;
Vk MinE }
l,*yEkU for(int index=0;index<MAX_KEY;index++){
JP{UgcaF if(hCallWnd[index]==NULL)
5SoZ$,a<e continue;
NoFs-GGGh if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
dO>k5!ge|: {
<Vz<{W3t SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
i0k+l bProcessed=TRUE;
hnp`s%e, }
XXa(305 }
a{<p'_ }
>Y7r\ if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
ybo#K for(int index=0;index<MAX_KEY;index++){
YniZ(
~^K if(hCallWnd[index]==NULL)
|ZS 57c: continue;
7%{R#$F if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
Hze-Ob8 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
G 6Wx3~ //lParam的意义可看MSDN中WM_KEYDOWN部分
nqZA|-} }
W3 ^z Ij }
`d75@0: }
c5X`_ return CallNextHookEx( hHook, nCode, wParam, lParam );
q:vz?G }
1*Sr5N[= .
_1jk 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:
g d z aRbx BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
lkV6qIj BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
,VPbUo@ S3SV.C:z> 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:
'I&|1I^ ,`;jvY~Ec LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
./#e1m?. {
'dkXYtKCB if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
#2h+dk$1 {
Ds{{J5Um% //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
i\(\MzW*' SaveBmp();
M(qxq(#{U return FALSE;
3rxo,pX94 }
CXTt(-FT …… //其它处理及默认处理
kGpV;F==* }
Ee&hG[sx }<SNO)h3 vKU`C?,L 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。
:bwM]k*$ =g@R%NDNV 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。
zu52 p4 CE{z-_{^ 二、编程步骤
D,k(~ I[ai: 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";
g]za"U|g 9ftN8Svw 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
fCB:733H DMB"Y, 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;
cFLd)mt/ O:1DOUYXs 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;
NUMi])HkN 3@G;'|z 5、 添加代码,编译运行程序。
WE")xhV6 )%s +? 三、程序代码
B#]_8svO tVunh3- ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
S."7+g7Ar #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
X:Q$gO?[4 #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
gA_krK,Z #if _MSC_VER > 1000
vVAb'`ysv #pragma once
7$
d}!S #endif // _MSC_VER > 1000
qbXz7s*{ #ifndef __AFXWIN_H__
fE^uF[-7? #error include 'stdafx.h' before including this file for PCH
job[bhK'Jt #endif
sAVefL? #include "resource.h" // main symbols
@&5 A&( class CHookApp : public CWinApp
4b4QbJ$ {
aM$\#Cx public:
eaQ90B4 CHookApp();
f/ajejYo?, // Overrides
AliRpxxd // ClassWizard generated virtual function overrides
~n6[$WjZA //{{AFX_VIRTUAL(CHookApp)
;-Ss# & public:
1~'_K9eE virtual BOOL InitInstance();
|q_
!.
a virtual int ExitInstance();
('t kZt%8 //}}AFX_VIRTUAL
>!}`%pk( //{{AFX_MSG(CHookApp)
QsOhz // NOTE - the ClassWizard will add and remove member functions here.
=Ey`M#t; // DO NOT EDIT what you see in these blocks of generated code !
n>P!u71 //}}AFX_MSG
Noh?^@T`Ov DECLARE_MESSAGE_MAP()
A:eG5K} };
_R7 w?!t8 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
t}Ss=0dJO BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
:mpiAs<%U" BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
=OYQM<q BOOL InitHotkey();
W/r^ugDV BOOL UnInit();
I]X #endif
cOkgoL" 4 H?uukmZl //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
4\p-TPM #include "stdafx.h"
x l0DN{PG #include "hook.h"
aX^+ O, #include <windowsx.h>
Pdw#o^Iq^ #ifdef _DEBUG
4<.O+hS
#define new DEBUG_NEW
r~8;kcu7 #undef THIS_FILE
DZe}y^F static char THIS_FILE[] = __FILE__;
5lTD]d #endif
.^[_V #define MAX_KEY 100
.$Bwb/a #define CTRLBIT 0x04
%9o+zg? RJ #define ALTBIT 0x02
M^6$
MMx #define SHIFTBIT 0x01
W&(f&{A #pragma data_seg("shareddata")
LmQ/#Gx HHOOK hHook =NULL;
Z)&D`RCf UINT nHookCount =0;
z/1{OL static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
9cd 8=][ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
K)S;:MLG= static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
z856 nl static int KeyCount =0;
>|3a
9S static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
0@)%h&mD #pragma data_seg()
frN3S HINSTANCE hins;
r7 VXeoX void VerifyWindow();
NP/>H9Q2% BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
zoP%u,XL //{{AFX_MSG_MAP(CHookApp)
@Z;1 g // NOTE - the ClassWizard will add and remove mapping macros here.
F
Z!J // DO NOT EDIT what you see in these blocks of generated code!
Y-p<qL|_ //}}AFX_MSG_MAP
\k@Z7+&7 END_MESSAGE_MAP()
+;q.Y? H9`
f0(H CHookApp::CHookApp()
xd8
*<,Wj {
)ofm_R'q* // TODO: add construction code here,
#tjmWGo, // Place all significant initialization in InitInstance
t`G)b&3_O }
:eOR-}p' nrpI5t.b CHookApp theApp;
8g*hvPc LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
*7" L]6 {
4_LQ?U>$ BOOL bProcessed=FALSE;
#Qbl=o4 if(HC_ACTION==nCode)
'#Dg8/r! {
{J]-<:XD if((lParam&0xc0000000)==0xc0000000){// Key up
YQgNv` l} switch(wParam)
],lV}Mlg* {
|d7$*7TvV case VK_MENU:
G>
\Tbx MaskBits&=~ALTBIT;
LdTdQ,s< break;
wAYB RY[ case VK_CONTROL:
C+%K6/J( MaskBits&=~CTRLBIT;
lIf(6nm@ break;
^0tw%6: case VK_SHIFT:
KJh,,xI>by MaskBits&=~SHIFTBIT;
mm[SBiFO\ break;
otr>3a*' default: //judge the key and send message
B@t'U=@7 break;
.Q>!B?) }
61_f3S(u for(int index=0;index<MAX_KEY;index++){
2cf' ,cv@8 if(hCallWnd[index]==NULL)
2~c~{ jl\ continue;
?Zz'|.l@ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
[@"wd_f{l {
cxP6-tV% SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
c
~Fdx bProcessed=TRUE;
naNyGE7) }
TJy4<rb }
}$gmK }
M>l^%` else if((lParam&0xc000ffff)==1){ //Key down
R,Oe$J< switch(wParam)
{6
.o=EyM{ {
\cuS>G case VK_MENU:
}
/:\U
p MaskBits|=ALTBIT;
Yrn"saVc, break;
Jx|I6y case VK_CONTROL:
HIf{Z* mb MaskBits|=CTRLBIT;
#^rU x. break;
2KI!af[I case VK_SHIFT:
]hTb@. MaskBits|=SHIFTBIT;
v{;7LXy0 break;
RL}KAGK default: //judge the key and send message
YQ(Po!NI\' break;
2t1I3yA'{z }
`/Y+1 aD for(int index=0;index<MAX_KEY;index++)
q'S
=Eav8 {
cd. brM if(hCallWnd[index]==NULL)
.%xzT J=! continue;
%_gho if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
>q7
%UK]& {
68t}w^= SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
j+^L~, S bProcessed=TRUE;
)\ 0F7Z }
5/I_w0 }
WDx
Mo`zT }
?Zcj}e.r if(!bProcessed){
\pY^^ l* for(int index=0;index<MAX_KEY;index++){
-50AX1h31: if(hCallWnd[index]==NULL)
G '#41>q+ continue;
..KwTf if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
?m"|QS!!K SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
N$ alUx* }
V@ :20m }
~&VN_;j_ }
F0dI/+ return CallNextHookEx( hHook, nCode, wParam, lParam );
cFZCf8:zB }
BzbDZV ,Og4
?fS BOOL InitHotkey()
^toAw8A=@0 {
uJow7-FD if(hHook!=NULL){
FY#!N
L nHookCount++;
H;KDZO9W return TRUE;
Ax<\jW< }
t[C1z else
@}LZ! y hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
w:ULi3 if(hHook!=NULL)
[ygF0-3ND nHookCount++;
<!'M} s return (hHook!=NULL);
UpUp8%fCU }
:Jxh2 BOOL UnInit()
<,8l *1C {
;j}yB if(nHookCount>1){
6m`{Z`c$ nHookCount--;
-l*g~7|j return TRUE;
F9Z@x) }
+]!lS7nsW BOOL unhooked = UnhookWindowsHookEx(hHook);
#MgvG, if(unhooked==TRUE){
nkY@_N nHookCount=0;
bI
ITPxz hHook=NULL;
l?E|RKp }
2VgP return unhooked;
cvo[s, p }
+1`t}hO v%91k BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
]n
v( aM?d {
tS?lB05TOR BOOL bAdded=FALSE;
BGWAh2w6 for(int index=0;index<MAX_KEY;index++){
<