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:
dUI5,3*
kB\{1; 一、实现方法
_X6'uJ &p0e)o~Ux 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:
&d# R'Z 8.E"[QktZ #pragma data_seg("shareddata")
gYpMwC{*d HHOOK hHook =NULL; //钩子句柄
Ui{%q@ UINT nHookCount =0; //挂接的程序数目
v3tJtb^'! static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
f:T?oR>2 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
% RSZ. static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
<n"BPXF~ static int KeyCount =0;
sp9gz~Kq static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
J=4>zQLW #pragma data_seg()
bz>X~
{ _rfhz 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。
$6hPTc<C =YO ]m< DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
5j%G7.S\ 6 SSDc/ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
\l%xuT cKey,UCHAR cMask)
ny={OhP- {
~E<2gMKjO BOOL bAdded=FALSE;
d:H'[l.F% for(int index=0;index<MAX_KEY;index++){
*{o7G a if(hCallWnd[index]==0){
GK(CuwJe hCallWnd[index]=hWnd;
FMfpjuHk HotKey[index]=cKey;
H=t"qEp HotKeyMask[index]=cMask;
]S|FK>U[ bAdded=TRUE;
niVR!l KeyCount++;
!xM5
A[f break;
KWTV!Wxb=K }
eRauyL"Q+ }
@NHh-&;w return bAdded;
<=uYfi 3, }
D28`?B9( //删除热键
8%@|/ BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
OMGggg {
G=dzP}B'WA BOOL bRemoved=FALSE;
5En6f`nR{ for(int index=0;index<MAX_KEY;index++){
#el27"QP0 if(hCallWnd[index]==hWnd){
NE995; if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
iyskADS hCallWnd[index]=NULL;
s?SspuV HotKey[index]=0;
x 3@-E HotKeyMask[index]=0;
oFY!NMq}: bRemoved=TRUE;
ON ?Y
Df KeyCount--;
D$>_W ,*V break;
,pNx(a }
5pO|^Gj1 }
X1L@
G }
K%^n. return bRemoved;
Rx%S<i;9 }
^5mc$~1` L9x-90'q, v
gN!9 DLL中的钩子函数如下:
!> UlvT- {Gxe%gu6K LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
7
,Rg~L {
:Pud%}' BOOL bProcessed=FALSE;
)?n'ZhsX if(HC_ACTION==nCode)
"Fz.#U {
"gM^o if((lParam&0xc0000000)==0xc0000000){// 有键松开
>rnVTK switch(wParam)
Z$oy;j99y {
h}bfZL case VK_MENU:
n*4`Tduu^ MaskBits&=~ALTBIT;
"LyD break;
cby# case VK_CONTROL:
i`,FXF) MaskBits&=~CTRLBIT;
;C]Ufk break;
h}b:-a case VK_SHIFT:
xNz(LZ.c MaskBits&=~SHIFTBIT;
#-hO\
QdC break;
*kr/,_K default: //judge the key and send message
>rG>Bz^Pu break;
Io6/Fv>! }
f|RmAP;X, for(int index=0;index<MAX_KEY;index++){
{.Tx70kn if(hCallWnd[index]==NULL)
^l &lwSRVt continue;
6(
HF)z if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
[P$Xr6# {
UA[`{rf SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
DM.lQ0xk bProcessed=TRUE;
r8k (L{W }
$KHm5*;nd }
kmB!NxF>)F }
!^J;S%MB:K else if((lParam&0xc000ffff)==1){ //有键按下
^E&PZA\,; switch(wParam)
8$00\><r {
-(VJ,)8t2 case VK_MENU:
ul{x|R MaskBits|=ALTBIT;
mh
}M|h5Im break;
jW/WG tz case VK_CONTROL:
D0.
)% MaskBits|=CTRLBIT;
%E?Srs}j break;
1/_g36\l$ case VK_SHIFT:
K!|eN_1A MaskBits|=SHIFTBIT;
VK}4<u break;
{>&~kM@ default: //judge the key and send message
'r;mm^cS? break;
O"m7r ds }
igO>)XbsM for(int index=0;index<MAX_KEY;index++){
MDMd$]CW if(hCallWnd[index]==NULL)
"gJ?LojB < continue;
lH-VqkR\ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
)m%uSSx# {
%1z;l. c SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
{I#_0Q,i bProcessed=TRUE;
J~~\0 u }
b UG,~\Z }
0RR |!zEu }
%L|fTndKH if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
%Ymi,o> for(int index=0;index<MAX_KEY;index++){
HB07 n4 | if(hCallWnd[index]==NULL)
=C %)(| continue;
bQ<qdGa if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
f@*69a8 SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
;p`1Y<d-O //lParam的意义可看MSDN中WM_KEYDOWN部分
AGhenDNV }
)'shpRB;1 }
Spm 0` }
|}"YUk^ return CallNextHookEx( hHook, nCode, wParam, lParam );
% "RJi? }
]lWqV X+vKY 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
I8H3*DE L G}{ibB BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
kR]P/4r BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
q8 v iC| rxCzPF 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
iO L$| Z( l{By]S LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
?d')#WnC {
!V|{(>+< if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
(m]l -Re {
["Zvwes#7 //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
G|i0n
SaveBmp();
~id6^#&> return FALSE;
4,RPidv%O }
Z0gtliJ@ …… //其它处理及默认处理
;QI9 OcE@/ }
D
0Xl`0"' p1N}2]e IQqUFP$8g 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
*>fr'jj1$ *^>"
h@J 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。
+VwQ=[y] y6(PG:L 二、编程步骤
{!,K[QwcI E@}F^0c 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";
?Uql30A $5nMD= 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
_!xrBdaJ IZVP- 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
8ud12^s$ ?sfqg gi 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;
O&!R7T Tigw+2 5、 添加代码,编译运行程序。
6St=r)_ ;zCUx*{ 三、程序代码
VcjbRpTy& O'4G'H) ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
|)x7qy` #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
Ek+R #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
k4+vI1Cs #if _MSC_VER > 1000
0U42QEG2 #pragma once
9a`LrB #endif // _MSC_VER > 1000
R hWQ:l] #ifndef __AFXWIN_H__
<q63?Ms' #error include 'stdafx.h' before including this file for PCH
\gA!)q.; #endif
~^wSwd[ #include "resource.h" // main symbols
NuZ2,<~9 class CHookApp : public CWinApp
Dfs^W{YA {
=VC18yA public:
=Rd`"]Mnfb CHookApp();
U`v2Yw3E // Overrides
<Iw{fj| // ClassWizard generated virtual function overrides
+pd,gG?dW //{{AFX_VIRTUAL(CHookApp)
X[tt'5 public:
s-p)^B virtual BOOL InitInstance();
'-wmY?ZFxy virtual int ExitInstance();
pcMzLMG< //}}AFX_VIRTUAL
!GOaBs //{{AFX_MSG(CHookApp)
j~v`q5X // NOTE - the ClassWizard will add and remove member functions here.
@SX%q&- // DO NOT EDIT what you see in these blocks of generated code !
Ak[X`e T //}}AFX_MSG
;|Cdq DECLARE_MESSAGE_MAP()
s5~k]"{j };
c4z&HQd LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
.*zN@y3 BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
^O|fw?, BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
tYA@J[" ^ BOOL InitHotkey();
/x3*oO1 BOOL UnInit();
161P%sGx2 #endif
,Ckcc la[pA //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
TY8gB!^ #include "stdafx.h"
_a09;C #include "hook.h"
n%E,[JT #include <windowsx.h>
/HIyQW\Ki- #ifdef _DEBUG
<83Ky;ry #define new DEBUG_NEW
s|C[{n<_ #undef THIS_FILE
s8-RXEPb static char THIS_FILE[] = __FILE__;
M0
z%<_<} #endif
*aErwGLB8 #define MAX_KEY 100
u(vZOf]jL #define CTRLBIT 0x04
r1!1u7dr
t #define ALTBIT 0x02
]V"P
&;m #define SHIFTBIT 0x01
v[L+PD
U #pragma data_seg("shareddata")
a (U52dO, HHOOK hHook =NULL;
[?K>s>it UINT nHookCount =0;
IQ_6DF static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
; Y/nS static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
j!+jLm!l static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
f:PlMv!{ static int KeyCount =0;
8eqTA8$? static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
T Q41i/{ #pragma data_seg()
ElO|6kOBYG HINSTANCE hins;
?G `m;S void VerifyWindow();
_E'?U BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
CL0lMZ //{{AFX_MSG_MAP(CHookApp)
9NTNulD>P // NOTE - the ClassWizard will add and remove mapping macros here.
8LV6E5Q // DO NOT EDIT what you see in these blocks of generated code!
YsmRY=3 //}}AFX_MSG_MAP
fcq8aW/z_ END_MESSAGE_MAP()
bPVk5G*ruP 461g7R%r CHookApp::CHookApp()
8063LWV {
("U<@~ // TODO: add construction code here,
JrcbJt // Place all significant initialization in InitInstance
b1Vr>:sK47 }
{
^o.f l~J d>9DwY CHookApp theApp;
X}( s(6 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
4/
` *mPW {
&S4*x|-C& BOOL bProcessed=FALSE;
Fk=SkSky if(HC_ACTION==nCode)
]SJ#:7 {
7z?;z<VJ if((lParam&0xc0000000)==0xc0000000){// Key up
|d0ZB_ci switch(wParam)
Kx9u|fp5 {
E2DfG^sGV case VK_MENU:
*JK0X MaskBits&=~ALTBIT;
]:e_Y,@ break;
S]3CRJU3` case VK_CONTROL:
]bds~OY5 U MaskBits&=~CTRLBIT;
l"ms:v break;
fkI 5~Y| case VK_SHIFT:
\'~
E%=Q MaskBits&=~SHIFTBIT;
)tG. 9"< break;
Q`F1t default: //judge the key and send message
k;\gYb%L break;
\2@J^O1, }
.wNXvnWr for(int index=0;index<MAX_KEY;index++){
[IAUJ09>I if(hCallWnd[index]==NULL)
`cp\UH@
continue;
+b 6R if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
9a*#r;R {
^kfqw0! SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
:k\#=u( bProcessed=TRUE;
ULiRuN0 6 }
K]|Ud No }
oU|G74e6 }
V'9.l6l else if((lParam&0xc000ffff)==1){ //Key down
JQ?`l)4 switch(wParam)
WEwa<%Ss {
&tH?m;V case VK_MENU:
w_{tS\ MaskBits|=ALTBIT;
Qvp"gut)%X break;
JuO47}i] 5 case VK_CONTROL:
~,/@]6S&Y MaskBits|=CTRLBIT;
?tYZ/ break;
:)1"yo\ case VK_SHIFT:
P<g(i 6] MaskBits|=SHIFTBIT;
}{R*pmv$bN break;
NQ`D"n default: //judge the key and send message
sD3ZZcy|= break;
X&9:^$m }
v+LJx for(int index=0;index<MAX_KEY;index++)
9gg{i6 {
m!7%5=Fc if(hCallWnd[index]==NULL)
rZ?:$],U! continue;
JpS}X\]i if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
JP4DV=}L {
6]v} SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
~5,^CTAM bProcessed=TRUE;
MZGhN
brd }
3}nk9S:jr }
0O"W0s"T# }
,D{7=mDVm if(!bProcessed){
X,Na4~JO( for(int index=0;index<MAX_KEY;index++){
{KgA
V if(hCallWnd[index]==NULL)
w(@r-2D" continue;
@HS*%N"* if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
*73gp
SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
c'2/ C5 }
ujV{AF`JfB }
]s=|+tz\V }
;TL.QN/l return CallNextHookEx( hHook, nCode, wParam, lParam );
,4'gj0 }
LGt>=|=bj c`<2&ke BOOL InitHotkey()
3y)\dln {
2j+w5KvU if(hHook!=NULL){
~xd?y*gk; nHookCount++;
9[/0 return TRUE;
&vrQ *jX }
s70Z&3A else
wsmgkg hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
+Kk1[fh-
if(hHook!=NULL)
8n3]AOc'~- nHookCount++;
poBeEpbs return (hHook!=NULL);
T >8P1p@A, }
iTHwH{! BOOL UnInit()
x)C} {
! VR&HEru if(nHookCount>1){
D1rVgM nHookCount--;
`/sNX<mp return TRUE;
&D3]O9a0; }
&3SS.&g4W BOOL unhooked = UnhookWindowsHookEx(hHook);
P3"R2- if(unhooked==TRUE){
*
BM|luYL nHookCount=0;
Qxz[ hHook=NULL;
h
/ }
LSta]81B4L return unhooked;
w*`:v$ }
z_>~=Mm g`pq*D BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
mn@1c4y {
ZxvH1qx8 BOOL bAdded=FALSE;
es7;eH*O9 for(int index=0;index<MAX_KEY;index++){
8$NVVw]2, if(hCallWnd[index]==0){
9d"*Z%!j hCallWnd[index]=hWnd;
5e7Y M@ng HotKey[index]=cKey;
XO]^ +'U}p HotKeyMask[index]=cMask;
AQZ<,TE0, bAdded=TRUE;
bqbG+g KeyCount++;
]q"&V\b break;
hF$`=hE,F~ }
1h@qcom9K_ }
@JGmOwZ return bAdded;
+JErc)% }
:$D*ab^^P ehW [LRtq BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
qcs)
p {
7 z BOOL bRemoved=FALSE;
8C{&i5kj\E for(int index=0;index<MAX_KEY;index++){
UPH#~D! if(hCallWnd[index]==hWnd){
.,u>WIUxj if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
OQumAj hCallWnd[index]=NULL;
5az%yS HotKey[index]=0;
KSs1EmB HotKeyMask[index]=0;
rf0Z5. bRemoved=TRUE;
<)ZQRE@ KeyCount--;
|5vcT,A break;
<ww D*t }
D=ej%]@iw }
Mqr]e#"o }
F?6kkLS/ return bRemoved;
EA~xxKq }
d[t0K] 1"y!wsM% void VerifyWindow()
"=a3"/u {
d&^b=d FDu for(int i=0;i<MAX_KEY;i++){
P8m0]T.&x if(hCallWnd
!=NULL){ e=9/3?El
if(!IsWindow(hCallWnd)){ Z 7@'I0;A
hCallWnd=NULL; nZioFE}
HotKey=0; wNi%u{T
HotKeyMask=0; B?%u<F
KeyCount--; lfAy$qP"}
} ZFLmD|q#{
} Iynks,ikA
} 2BC!,e$Z
} qlcd[Y*B
~DD
_n
BOOL CHookApp::InitInstance() 2mEqfy
{ C@Wzg
AFX_MANAGE_STATE(AfxGetStaticModuleState()); I7vP*YE 7F
hins=AfxGetInstanceHandle(); 5.^pD9 [mT
InitHotkey(); w"0$cL3
return CWinApp::InitInstance(); k^oSG1F
} 8sj2@d
a[hF2/*
int CHookApp::ExitInstance() q]{gAGe~
{ r $S9/
VerifyWindow(); 2xN7lfu1RB
UnInit(); g/C 7wc
return CWinApp::ExitInstance(); |&@q$d
} \>S.nW
j#f/M3
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file OmuE l>
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) :Pq&l.
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ c^= q(V
#if _MSC_VER > 1000 8
o}5QOW
#pragma once k1D7=&i
#endif // _MSC_VER > 1000 w5z]=dN
mRx `G(u:v
class CCaptureDlg : public CDialog b_Y+XXb<
{ 9SeGkwec?$
// Construction (`4&