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:
X@7K#@5
,w/f:-y 一、实现方法
YErn50L WsCzC_'j. 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:
+6*
.lRA N#`aVW'{v2 #pragma data_seg("shareddata")
6c>tA2G|8 HHOOK hHook =NULL; //钩子句柄
?ixzlDto\ UINT nHookCount =0; //挂接的程序数目
\T_?<t,UT static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
IJn r^S8 static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
f-tV8 static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
)>LC*_v static int KeyCount =0;
C9}2F{8 static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
uhLg2G^h #pragma data_seg()
&xqe8!FeA g/q$;cB 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。
CFh&z^]PR 'ga1SbA] 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:
H\3CvFm Xklp6{VH9 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
[VPqI~u5) cKey,UCHAR cMask)
ZtEHP`Iin
{
NCvwg BOOL bAdded=FALSE;
}#
-N7=h for(int index=0;index<MAX_KEY;index++){
3RRZVc*
^ if(hCallWnd[index]==0){
'U)~|(\i hCallWnd[index]=hWnd;
?#kI9n<O HotKey[index]=cKey;
7@vcQv
kC HotKeyMask[index]=cMask;
@ec QVk bAdded=TRUE;
=dX*:An KeyCount++;
{F
k]X#j break;
;8g#"p*& }
(cYc03" }
-JZl?hY( return bAdded;
>CPkL_@VZ= }
jVRd[ //删除热键
uB,B%XHj BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
HXdPKS4q {
aXC`yQ? BOOL bRemoved=FALSE;
~N'KIP[W for(int index=0;index<MAX_KEY;index++){
}C#YR(] if(hCallWnd[index]==hWnd){
jd2Fh):q if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
+d6E)~qKL hCallWnd[index]=NULL;
v:6b&wSL3 HotKey[index]=0;
$zmES tcm HotKeyMask[index]=0;
FcW ?([l bRemoved=TRUE;
Lp
]d4"L;3 KeyCount--;
}UGPEf\ break;
I;-{#OE, }
1C$^S]v%a }
K.z}%a }
yl'~H;su return bRemoved;
WejY
b;KS }
v8%]^` ' ,Fr{i1Ky 6PMu;# DLL中的钩子函数如下:
*q0N$}k OC>" + LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
ZY/at/v {
p-7dJ BOOL bProcessed=FALSE;
7>ODaj
if(HC_ACTION==nCode)
"Z{^i3gN {
+bO{UC[ if((lParam&0xc0000000)==0xc0000000){// 有键松开
d=5D 9'+ switch(wParam)
QHM39Eu] {
;:!LAe
case VK_MENU:
9xKFX|*$ MaskBits&=~ALTBIT;
Lw#hnLI. break;
nu3 A'E`'k case VK_CONTROL:
}%1E9u MaskBits&=~CTRLBIT;
AjlG_F break;
YT:1=Nf} case VK_SHIFT:
Rp<Xu6r MaskBits&=~SHIFTBIT;
]t=># break;
,f1wN{P default: //judge the key and send message
e!-'O0-Kw break;
OS9v.pz }
};+s0:H for(int index=0;index<MAX_KEY;index++){
<^~F~]wnH if(hCallWnd[index]==NULL)
S;c=6@" continue;
W[?B@ sdSZ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
='JX_U`A^F {
B 3h<K} SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
Ww p^dx`! bProcessed=TRUE;
E7<:>Uh }
i!HGM=f }
TXa XJIp }
fr?eOigbl else if((lParam&0xc000ffff)==1){ //有键按下
MQ+ek4 switch(wParam)
QCo^#- {
8vRiVJ8QS: case VK_MENU:
9j"\Lr*o" MaskBits|=ALTBIT;
l}^#kHSyd break;
,J^Op
case VK_CONTROL:
e)7)~g54 MaskBits|=CTRLBIT;
bDo'hDmW break;
$>UzXhf}\ case VK_SHIFT:
}:mI6zsNj MaskBits|=SHIFTBIT;
$!f$R`R^Q\ break;
1fy{@j(W default: //judge the key and send message
cTnbI4S; break;
M<)2 }
GN<I|mGLJK for(int index=0;index<MAX_KEY;index++){
hF~B&^dd. if(hCallWnd[index]==NULL)
$T4PC5. continue;
6S<$7=$= if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
%awS* {
,gvX ~k SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
`9+EhP$RS bProcessed=TRUE;
IO#W#wW$M }
L@Z
&v'A }
~30Wb9eL }
,&=`T7i if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
UjaC( c for(int index=0;index<MAX_KEY;index++){
z aF0nov if(hCallWnd[index]==NULL)
"{_"NjH continue;
deoM~r9s if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
pJz8e&wyLM SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
o0'av+e7 //lParam的意义可看MSDN中WM_KEYDOWN部分
1l_}O1 }
b-?o?}* }
~@D%qbN }
fn OkH return CallNextHookEx( hHook, nCode, wParam, lParam );
<k](s }
q4i8Sp> Wu( 8G 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:
kZ9<j+. yk<jlVF$j BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
-ZP&zOsDr BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
\bic.0-
:XSc#H4 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:
ib\[ ~rg e:LZ s0 LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
}+
2"?f|] {
*\KMkx if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
RYl3txw {
NP`s[ //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
&&1Y"dFs SaveBmp();
df6Ν4L return FALSE;
(Dm"e` }
npcBpGL{ …… //其它处理及默认处理
)O@^H }
5
?~-Vv31s 9c{%m4 xdfvme[ 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。
Cw[Od"B\?U qM>OE8c#/ 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。
n,jE#Z.D C.eV|rc@T 二、编程步骤
U.Chf9a- N~}v:rK>g 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";
S~rVRC"<xo '%-xe3 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
J)8pqa /-{O\7-D 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;
IEoR7: >\7RIy3 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;
rfXF 01I ~I\r1Wj; 5、 添加代码,编译运行程序。
:qCm71* M,\|V3s 三、程序代码
VIz{}_~'s ;8L+_YCa ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
i[ Gw7'f #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
_N,KHxsG8B #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
}`9fZK{. @ #if _MSC_VER > 1000
W}R= #pragma once
Z;Ir>^< #endif // _MSC_VER > 1000
p21=$?k!; #ifndef __AFXWIN_H__
+A'q#~yILa #error include 'stdafx.h' before including this file for PCH
F@_Egi #endif
1RI #kti-" #include "resource.h" // main symbols
K^,&ub.L) class CHookApp : public CWinApp
Y1yXB).AH8 {
]O[+c*|w public:
A|
gs Uh CHookApp();
K{=r.W // Overrides
'TK$ndy;7} // ClassWizard generated virtual function overrides
!X\sQNp //{{AFX_VIRTUAL(CHookApp)
np`gcj# public:
5&n988gC8 virtual BOOL InitInstance();
4uO
@`0:x virtual int ExitInstance();
1%SJ1oY //}}AFX_VIRTUAL
%;=IMMK //{{AFX_MSG(CHookApp)
pu2 wEQ // NOTE - the ClassWizard will add and remove member functions here.
, `[Z`SUk` // DO NOT EDIT what you see in these blocks of generated code !
8g#
c%eZ //}}AFX_MSG
>%n8W>^^4 DECLARE_MESSAGE_MAP()
qXP1Q3 };
/^z/]!JG:V LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
r21?c|IP BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
D% v:PYf BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
}{#;;5KrB BOOL InitHotkey();
fR]p+\#8u* BOOL UnInit();
`eMrP` #endif
b[{m>Fa+o# /@9-!cL //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
Jo7fxWO_g #include "stdafx.h"
"%.|n| #include "hook.h"
z`86-Ov #include <windowsx.h>
RQj`9F #ifdef _DEBUG
=1{H
Sf #define new DEBUG_NEW
eHVdZ'%x #undef THIS_FILE
3i]"#wK static char THIS_FILE[] = __FILE__;
<O,'5+zG% #endif
VL_)]LR*) #define MAX_KEY 100
4cXAT9 #define CTRLBIT 0x04
dxzvPgi? #define ALTBIT 0x02
di]$dl|Wi #define SHIFTBIT 0x01
SE-!|WR #pragma data_seg("shareddata")
bGGeg%7 HHOOK hHook =NULL;
ql!5m\ UINT nHookCount =0;
'\ph`Run static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
@K,2mhE~h static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
nu4Pc static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
zVp[YOS&c static int KeyCount =0;
o-\ok|,)#j static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
8eOl@}bV #pragma data_seg()
2k.S[?) HINSTANCE hins;
L"""\5Bn( void VerifyWindow();
>QYh}Z-/% BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
uuI3NAi~ //{{AFX_MSG_MAP(CHookApp)
7j@^+rkr3f // NOTE - the ClassWizard will add and remove mapping macros here.
(A7T}znG // DO NOT EDIT what you see in these blocks of generated code!
u~#%P&3_W //}}AFX_MSG_MAP
v
t^r1j END_MESSAGE_MAP()
:@:g*w2K sl~b\j CHookApp::CHookApp()
H"Q(2I {
xT{TVHdU // TODO: add construction code here,
}U2[? // Place all significant initialization in InitInstance
euRCBzc }
TZ^{pvBy 1k!D0f3qb CHookApp theApp;
MB}:GY? LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
>=4sPF) {
"F&Tnhh4 BOOL bProcessed=FALSE;
Ro$j1Aw( if(HC_ACTION==nCode)
EwTS!gL {
Q<z)q<e if((lParam&0xc0000000)==0xc0000000){// Key up
,)Yao;Cvd switch(wParam)
y' 2<qj {
vad|Rp l case VK_MENU:
;
qO@A1Hq MaskBits&=~ALTBIT;
S|l&fb n break;
g;$E1U=R-E case VK_CONTROL:
f&K}IM8& # MaskBits&=~CTRLBIT;
7^c2e*S break;
aZ8h[#]7 case VK_SHIFT:
w(aUEWYL MaskBits&=~SHIFTBIT;
6!*K/2:O break;
%(fL? default: //judge the key and send message
%wOOzp` break;
!>\9t9 }
{PL,VY)Z for(int index=0;index<MAX_KEY;index++){
N[>:@h if(hCallWnd[index]==NULL)
3 Q@9S continue;
wyp{KIV if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
TV<Aj"xw {
KUbJe)}g SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
#U\$@4D bProcessed=TRUE;
,bxz]S1W }
6!@0VI&P }
!5NGlqEF# }
`Rrr>vj else if((lParam&0xc000ffff)==1){ //Key down
ma3Qi/ switch(wParam)
#sL/y {
Tu==49 case VK_MENU:
S=4R5igrC MaskBits|=ALTBIT;
,dOMW+{ break;
T{ok +$w2 case VK_CONTROL:
4yhcK& MaskBits|=CTRLBIT;
<8$Md4r break;
@?m+Z"o|z case VK_SHIFT:
Ohc^d"[7 MaskBits|=SHIFTBIT;
Q
Qi@>v|d break;
70{RDj6{ default: //judge the key and send message
:u
AjV break;
M'YJ" }
,eDu$8J9 for(int index=0;index<MAX_KEY;index++)
*g*VCO {
u9BjgK(M if(hCallWnd[index]==NULL)
:fhB*SYK continue;
Q@3B{ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
!h?=Wv
==] {
("b*? : B SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
'g2vX&=$A bProcessed=TRUE;
z1#oWf{* }
f*v1J<1# }
@bE~@4mOu }
mLQUcYfR if(!bProcessed){
URLk9PI for(int index=0;index<MAX_KEY;index++){
3Mur*tj# if(hCallWnd[index]==NULL)
f'i6QMk\& continue;
i]dz}= j' if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
;c$@@l SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
j"i#R1T }
:1*zr }
]r!QmWw~V }
q P'[&h5Y return CallNextHookEx( hHook, nCode, wParam, lParam );
2Sjt=LOc=" }
ZzT&$J7]`{ ldYeX+J
_ BOOL InitHotkey()
r
3|4gG {
YroNpu]s if(hHook!=NULL){
g1ytT%] nHookCount++;
VE*j*U
j return TRUE;
IyOpju)? }
aTG[=)xL else
#>XeR>T hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
%2}C'MqS if(hHook!=NULL)
bb}?h]a nHookCount++;
=tn Tdp0F return (hHook!=NULL);
Ww=O=c5uOu }
e$32 BOOL UnInit()
=!<^^6LZ {
&>g~-s if(nHookCount>1){
8<{;=m8cQ nHookCount--;
Y+@g~TE return TRUE;
Li]k7w?H }
Gnk|^i;t BOOL unhooked = UnhookWindowsHookEx(hHook);
(_U^ if(unhooked==TRUE){
,z G(u 1 nHookCount=0;
OT;cfkf7 hHook=NULL;
M!#AfIyB }
@iRO7 6m return unhooked;
A4
5m)wQ }
#)`\!)? St2Q7K5s{ BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
`R0Y+#$8h {
5j`v`[B; BOOL bAdded=FALSE;
R:f7LRF/\ for(int index=0;index<MAX_KEY;index++){
f1J%]g! if(hCallWnd[index]==0){
{@45?L(' hCallWnd[index]=hWnd;
5 < GDW= HotKey[index]=cKey;
jq[x DwPG HotKeyMask[index]=cMask;
B4^`Sw bAdded=TRUE;
F"[3c6yF KeyCount++;
kW+G1| break;
:3 y_mf> }
nj }
a,cC!
return bAdded;
wV:C<Mg7q }
)88nMH- A9;0y jae BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
;'^, ,{ {
sf)W~Lx5a BOOL bRemoved=FALSE;
tr=@+WHp for(int index=0;index<MAX_KEY;index++){
a_{6Qdl if(hCallWnd[index]==hWnd){
s:b"\7 if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
n_9x"m$ hCallWnd[index]=NULL;
s!de2z HotKey[index]=0;
sOz sY7z3Z HotKeyMask[index]=0;
) Fx?% bRemoved=TRUE;
ZF'HM@cfo KeyCount--;
11{y}J break;
>)3VbO }
o|rzN\WJn }
*Ru2:}?MpS }
CC#C return bRemoved;
!=[>r'+3 }
J*K<FFp3< rN#\AN void VerifyWindow()
mgcN( n1 {
Vhph`[dC{ for(int i=0;i<MAX_KEY;i++){
$20s]ywS if(hCallWnd
!=NULL){ EY$?^iS
if(!IsWindow(hCallWnd)){ LM6]kll
hCallWnd=NULL; >3P9 i ;W
HotKey=0; RUX8qT(Z
HotKeyMask=0; VYigxhP7
KeyCount--; {:)vwUe{
} s.rT]
} Ay%:@j(E
}
Q;20T
} yoU2AMH2D^
c[:Wf<%|
BOOL CHookApp::InitInstance() !g2a|g
{ =YHt9fb$c
AFX_MANAGE_STATE(AfxGetStaticModuleState()); uP6-cs
hins=AfxGetInstanceHandle(); T V;BNCg
InitHotkey(); )eq}MaW+j
return CWinApp::InitInstance(); 85hQk+Bu4
} ~p.%.b;~t
(:OHyeNt
int CHookApp::ExitInstance() qiU5{}
{ VA2<r(y~(
VerifyWindow(); QnU0"_-
UnInit(); :H\&2/j
return CWinApp::ExitInstance(); $T/#1w P
} [-58Ezyr
u-39r^`5
////////////////////////////////////////////////////////////////////// CaptureDlg.h : header file SSQT ;>
#if !defined(AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_) $3 vhddO
#define AFX_CAPTUREDLG_H__97B51708_C928_11D5_B7D6_0080C82BE86B__INCLUDED_ 045\i[l=
#if _MSC_VER > 1000 !-RwB@\
#pragma once zAI|Jv@
#endif // _MSC_VER > 1000 oZ-FF'
8}z3CuM
class CCaptureDlg : public CDialog `M)E* G
{ 6l[G1KkV
// Construction xE1rxPuq)d
public: c _mq
BOOL bTray; ^K.*.|
BOOL bRegistered; /x/4NeD
BOOL RegisterHotkey(); 6Hn)pD#U
UCHAR cKey; n$
dw<y
UCHAR cMask; 6V
P)$h8
void DeleteIcon(); h>|u:]I>
void AddIcon(); r w\D>}\
UINT nCount; [ro t
void SaveBmp(); _NT[
~M_Q
CCaptureDlg(CWnd* pParent = NULL); // standard constructor RM#fX^)=
// Dialog Data Of#K:`1@
//{{AFX_DATA(CCaptureDlg) $l#{_~
"m7
enum { IDD = IDD_CAPTURE_DIALOG }; VWD.J
CComboBox m_Key; GmAj<