你的电脑有没有摄像头？看到别人用QQ玩视屏你会不会去想怎么实现的？这里介绍使用DELPHI使用MS的AVICAP32.DLL就可轻松的实现对摄像头编程，如果再加上你的网络编程水平，实现一个视屏聊天就不成什么问题了。

　　看看下面代码的代码：

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';

　　上面的代码就是我们主要用到的一个函数和常量的定义。

　　好了，打开你的Delphi，新建一个工程，将上面的定义加上吧。

　　新建一个窗口，放个Panel上去，添加一个按钮，Caption设置为"开始"这里需要定义一个全局变量，var hWndC : THandle; 开始按钮代码如下：

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运行一下，怎么样，是不是可以看到摄像头的视屏了？那怎么停下来？再加个按钮caption设置成"停止" 。代码如下： if hWndC <> 0 then begin SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0); hWndC := 0; end;

　　视屏截到了，怎么把它给保存下来呢？下面按两种方式保存，一个是BMP静态图，一个是AVI动画。

　　再放三个按钮到窗体上去，caption分别设置成"保存BMP"、"开始录像"、"停止录像"，三个按钮的代码分别如下：

//保存BMP if hWndC <> 0 then begin SendMessage(hWndC,WM_CAP_SAVEDIB,0,longint(pchar('c:\test.bmp'))); end; //开始录像 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; //停止录像 if hWndC <> 0 then begin SendMessage(hWndC, WM_CAP_STOP, 0, 0); end;

　再运行看看吧。。可以保存几张图看看，也可以录成AVI以后慢慢欣赏。

　　程序运行效果：

 

　　完整的程序代码如下：

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.

　　如果电脑没有摄像头，但又想看看程序的效果，可以么？

　　当然可以，找个虚拟摄像头不就搞定，大家可以试试SoftCam这个软件，它是一个名副其实的软件摄像机，能模拟成为“真实的”摄像机，提醒一下各位，大家可不要用这个东东用在QQ，MSN等聊天软件上欺骗MM或GG啊。

　　关于摄像头编程，大家也可以看看这组VCL组件：DSPack，DSPack是一套使用微软Direct Show和DirectX技术的类和组件，设计工作于DirectX 9，支持系统Win9X, ME, 2000和Windows XP。

　　好了，就介绍这些了，至于视屏聊天怎么实现，就看你的了，无非是把数据压缩传输给对方，显示出来，不过话又说回来，看似简单，实现起来还有些难度的。

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