網路攝影機（簡介）

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你的電腦有沒有網路攝影機？看到別人用QQ玩視屏你會不會去想怎麼實現的？
這裡介紹使用DELPHI使用MS的AVICAP32.DLL就可輕鬆的實現對網路攝影機編程，
如果再加上你的網路編程水平，實現一個視屏聊天就不成什麼問題了。
看看下面代碼的代碼：

const WM_CAP_START = WM_USER;
const WM_CAP_STOP = WM_CAP_START + 68;
const WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10;
const WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11;
const WM_CAP_SAVEDIB = WM_CAP_START + 25;
const WM_CAP_GRAB_FRAME = WM_CAP_START + 60;
const WM_CAP_SEQUENCE = WM_CAP_START + 62;
const WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START + 20;
const WM_CAP_SEQUENCE_NOFILE =WM_CAP_START+ 63
const WM_CAP_SET_OVERLAY =WM_CAP_START+ 51
const WM_CAP_SET_PREVIEW =WM_CAP_START+ 50
const WM_CAP_SET_CALLBACK_VIDEOSTREAM = WM_CAP_START +6;
const WM_CAP_SET_CALLBACK_ERROR=WM_CAP_START +2;
const WM_CAP_SET_CALLBACK_STATUSA= WM_CAP_START +3;
const WM_CAP_SET_CALLBACK_FRAME= WM_CAP_START +5;
const WM_CAP_SET_SCALE=WM_CAP_START+ 53
const WM_CAP_SET_PREVIEWRATE=WM_CAP_START+ 52

function capCreateCaptureWindowA(lpszWindowName : PCHAR; dwStyle : longint; x : integer;
y : integer;nWidth : integer;nHeight : integer;ParentWin : HWND;
nId : integer): HWND;STDCALL EXTERNAL ‘AVICAP32.DLL‘;

上面的代碼就是我們主要用到的一個函數和常量的定義。

好了，開啟你的Delphi，建立一個工程，將上面的定義加上吧。

建立一個視窗，放個Panel上去，添加一個按鈕，Caption設定為 "開始 "
這裡需要定義一個全域變數，var hWndC : THandle;

開始按鈕代碼如下：

begin
hWndC := capCreateCaptureWindowA(‘My Own Capture Window‘,WS_CHILD or WS_VISIBLE ,Panel1.Left,Panel1.Top,Panel1.Width,Panel1.Height,Form1.Handle,0);

hWndC := capCreateCaptureWindowA(‘My Own Capture Window‘,WS_CHILD or WS_VISIBLE ,Panel1.Left,Panel1.Top,Panel1.Width,Panel1.Height,Form1.Handle,0);
if hWndC <> 0 then
begin
SendMessage(hWndC, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, 0);
SendMessage(hWndC, WM_CAP_SET_CALLBACK_ERROR, 0, 0);
SendMessage(hWndC, WM_CAP_SET_CALLBACK_STATUSA, 0, 0);
SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0);
SendMessage(hWndC, WM_CAP_SET_SCALE, 1, 0);
SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, 66, 0);
SendMessage(hWndC, WM_CAP_SET_OVERLAY, 1, 0);
SendMessage(hWndC, WM_CAP_SET_PREVIEW, 1, 0);
end;
按F9運行一下，怎麼樣，是不是可以看到網路攝影機的視屏了？

那怎麼停下來？再加個按鈕caption設定成 "停止 "
代碼如下：
if hWndC <> 0 then begin
SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
hWndC := 0;
end;

視屏截到了，怎麼把它給儲存下來呢？

下面按兩種方式儲存，一個是BMP靜態圖，一個是AVI動畫。

再放三個按鈕到表單上去，caption分別設定成 "儲存BMP "、 "開始錄影 "、 "停止錄影 "
三個按鈕的代碼分別如下：

//儲存BMP
if hWndC <> 0 then begin
SendMessage(hWndC,WM_CAP_SAVEDIB,0,longint(pchar(‘c:\\test.bmp‘)));
end;

//開始錄影
if hWndC <> 0 then
begin
SendMessage(hWndC,WM_CAP_FILE_SET_CAPTURE_FILEA,0, Longint(pchar(‘c:\\test.avi‘)));
SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0);
end;

//停止錄影
if hWndC <> 0 then begin
SendMessage(hWndC, WM_CAP_STOP, 0, 0);
end;

再運行看看吧。。可以儲存幾張圖看看，也可以錄成AVI以後慢慢欣賞。

程式運行效果： [ 相關貼圖 ]
http://yousoft.hi.com.cn/upload/forum/2004715161959.jpg

完整的程式碼如下：

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls;

type
TForm1 = class(TForm)
Panel1: TPanel;
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
Button5: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure Button5Click(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
private
hWndC : THandle;
public
{ Public declarations }
end;

var
Form1: TForm1;

const WM_CAP_START = WM_USER;
const WM_CAP_STOP = WM_CAP_START + 68;
const WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10;
const WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11;
const WM_CAP_SAVEDIB = WM_CAP_START + 25;
const WM_CAP_GRAB_FRAME = WM_CAP_START + 60;
const WM_CAP_SEQUENCE = WM_CAP_START + 62;
const WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START + 20;
const WM_CAP_SEQUENCE_NOFILE =WM_CAP_START+ 63
const WM_CAP_SET_OVERLAY =WM_CAP_START+ 51
const WM_CAP_SET_PREVIEW =WM_CAP_START+ 50
const WM_CAP_SET_CALLBACK_VIDEOSTREAM = WM_CAP_START +6;
const WM_CAP_SET_CALLBACK_ERROR=WM_CAP_START +2;
const WM_CAP_SET_CALLBACK_STATUSA= WM_CAP_START +3;
const WM_CAP_SET_CALLBACK_FRAME= WM_CAP_START +5;
const WM_CAP_SET_SCALE=WM_CAP_START+ 53
const WM_CAP_SET_PREVIEWRATE=WM_CAP_START+ 52

function capCreateCaptureWindowA(lpszWindowName : PCHAR;
dwStyle : longint;x : integer;y : integer;nWidth : integer;
nHeight : integer;ParentWin : HWND;nId : integer): HWND;
STDCALL EXTERNAL ‘AVICAP32.DLL‘;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
hWndC := capCreateCaptureWindowA(‘My Own Capture Window‘,WS_CHILD or WS_VISIBLE ,Panel1.Left,Panel1.Top,Panel1.Width,Panel1.Height,Form1.Handle,0);

hWndC := capCreateCaptureWindowA(‘My Own Capture Window‘,WS_CHILD or WS_VISIBLE ,Panel1.Left,Panel1.Top,Panel1.Width,Panel1.Height,Form1.Handle,0);
if hWndC <> 0 then
begin
SendMessage(hWndC, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, 0);
SendMessage(hWndC, WM_CAP_SET_CALLBACK_ERROR, 0, 0);
SendMessage(hWndC, WM_CAP_SET_CALLBACK_STATUSA, 0, 0);
SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0);
SendMessage(hWndC, WM_CAP_SET_SCALE, 1, 0);
SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, 66, 0);
SendMessage(hWndC, WM_CAP_SET_OVERLAY, 1, 0);
SendMessage(hWndC, WM_CAP_SET_PREVIEW, 1, 0);
end;

end;

procedure TForm1.Button2Click(Sender: TObject);
begin
if hWndC <> 0 then begin
SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
hWndC := 0;
end;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
if hWndC <> 0 then begin
SendMessage(hWndC,WM_CAP_SAVEDIB,0,longint(pchar(‘c:\\test.bmp‘)));
end;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
if hWndC <> 0 then
begin
SendMessage(hWndC,WM_CAP_FILE_SET_CAPTURE_FILEA,0, Longint(pchar(‘c:\\test.avi‘)));
SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0);
end;
end;

procedure TForm1.Button5Click(Sender: TObject);
begin
if hWndC <> 0 then begin
SendMessage(hWndC, WM_CAP_STOP, 0, 0);
end;
end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
if hWndC <> 0 then begin
SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
end;
end;

end.

網路攝影機（簡介）