最近在使用Usb摄像头做了个项目,其中写了一个操作usb摄像头类分享给大家

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{       操作USB摄像头类                                 }

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{       作者：lqen                                      }

{       日期：2015.05.18                                }

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unit untUsbCamera;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls, ExtCtrls, jpeg;

const WM_CAP_START = WM_USER;

const WM_CAP_STOP = WM_CAP_START + ;

const WM_CAP_DRIVER_CONNECT = WM_CAP_START + ;

const WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + ;

const WM_CAP_SAVEDIB = WM_CAP_START + ;

const WM_CAP_GRAB_FRAME = WM_CAP_START + ;

const WM_CAP_SEQUENCE = WM_CAP_START + ;

const WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START + ;

const WM_CAP_SEQUENCE_NOFILE = WM_CAP_START + ;

const WM_CAP_SET_OVERLAY = WM_CAP_START + ;

const WM_CAP_SET_PREVIEW = WM_CAP_START + ;

const WM_CAP_SET_CALLBACK_VIDEOSTREAM = WM_CAP_START + ;

const WM_CAP_SET_CALLBACK_ERROR = WM_CAP_START + ;

const WM_CAP_SET_CALLBACK_STATUSA = WM_CAP_START + ;

const WM_CAP_SET_CALLBACK_FRAME = WM_CAP_START + ;

const WM_CAP_SET_SCALE = WM_CAP_START + ;

const WM_CAP_SET_PREVIEWRATE = WM_CAP_START + ;

const WM_CAP_DLG_VIDEODISPLAY = WM_CAP_START + ; //打开视频格式设置对话框，选择数字视频的框架大小和视频图像的色深，以及捕获视频图像的压缩格式。

type

  TUsbCamera = class

  private

    FPanel: TPanel;

    hWndC: THandle; //定义捕捉窗句柄

    FIsOpen: boolean;

    function BmpToJpg(BmpPath: string): string;

    function Image_FitBitmap(const Source, Dest: string; const x, y: integer): Boolean;

  protected

  public

    constructor Create();

    destructor Destroy; override;

    function Play(Panel: TPanel): boolean;

    function Stop: boolean;

    function StartRecord(FileName: string): Boolean;

    function StopRecord: Boolean;

    function Capture(FileName: string): Boolean;

  published

    property IsOpen: boolean read FIsOpen write FIsOpen;

  end;

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

implementation

{ TUsbCamera }

function TUsbCamera.BmpToJpg(BmpPath: string): string;

var

  Jpg: TJpegImage;

  BMP: TBitMap;

begin

  Result := '';

  BmpPath := Trim(BmpPath);

  Jpg := TJpegImage.Create;

  BMP := TBitmap.Create;

  try

    BMP.LoadFromFile(BmpPath);

    Jpg.Assign(BMP);

    Jpg.SaveToFile(Copy(BmpPath, , Length(BmpPath) - ) + 'jpg');

    Result := Copy(BmpPath, , Length(BmpPath) - ) + 'jpg';

  finally

    BMP.Free;

    Jpg.Free;

    BMP := nil;

    Jpg := nil;

  end;

end;

function TUsbCamera.Image_FitBitmap(const Source, Dest: string; const x, y: integer): Boolean;

var

  abmp, bbmp: tbitmap; //定义变量  abmp为源对象变量  bbmp为目的对象变量

begin

  abmp := tbitmap.Create; //创建位图资源

  bbmp := tbitmap.Create; //创建位图资源

  try

    abmp.LoadFromFile(Source); //载入源位图资源

    bbmp.Width := x; //设置目的位图的宽

    bbmp.Height := y; //设置目的位图的高

    bbmp.PixelFormat := pfDevice; //设置位图格式为当前设备默认格式

    SetStretchBltMode(bbmp.Canvas.Handle, COLORONCOLOR); //设置指位图拉伸模式

    StretchBlt(bbmp.Canvas.Handle, , , bbmp.Width, bbmp.Height, abmp.Canvas.Handle, , , abmp.Width, abmp.Height, srccopy); //从源矩形中复制一个位图到目标矩形并适当压缩

    bbmp.SaveToFile(Dest); //保存转换后的目的图片

  finally

    abmp.Free; //释放资源

    bbmp.Free; //释放资源

  end;

end;

function TUsbCamera.Capture(FileName: string): boolean;

begin

  Result := False;

  if hWndC <>  then

  begin

    ForceDirectories(ExtractFilePath(FileName));

    if SendMessage(hWndC, WM_CAP_SAVEDIB, , longint(pchar(FileName))) <>  then exit; //截图

    if FileExists(FileName) then

    begin

      Image_FitBitmap(FileName, FileName, , );

      FileName := BmpToJpg(FileName);

      Result := True;

    end;

  end;

end;

constructor TUsbCamera.Create();

begin

end;

destructor TUsbCamera.Destroy;

begin

  Stop;

  inherited;

end;

function TUsbCamera.Play(Panel: TPanel): boolean;

begin

  Result := False;

  FPanel := Panel;

  //使用Tpanel控件来创建捕捉窗口

  hWndC := CapCreateCaptureWindowA('My Own Capture Window',

    WS_CHILD or WS_VISIBLE, //窗口样式

    , //X坐标

    , //Y坐标

    FPanel.Width, //窗口宽

    FPanel.Height, //窗口高

    FPanel.Handle, //窗口句柄

    ); //一般为0

  if hWndC <>  then

  begin

    if SendMessage(hWndC, WM_CAP_SET_CALLBACK_VIDEOSTREAM, , ) <>  then exit;

    //捕捉一个视频流

    if SendMessage(hWndC, WM_CAP_SET_CALLBACK_ERROR, , ) <>  then exit; //得到一个设备错误

    if SendMessage(hWndC, WM_CAP_SET_CALLBACK_STATUSA, , ) <>  then exit; //得到一个设备状态

    if SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, , ) <>  then exit;

    //将一个捕捉窗口与一个设备驱动相关联

    if SendMessage(hWndC, WM_CAP_SET_SCALE, , ) <>  then exit;

    if SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, , ) <>  then exit;

    SendMessage(hWndC, WM_CAP_SET_OVERLAY, , );

    if SendMessage(hWndC, WM_CAP_SET_PREVIEW, , ) <>  then exit;

    Result := True;

    FIsOpen := True;

  end;

end;

function TUsbCamera.StartRecord(FileName: string): Boolean;

begin

  Result := False;

  if hWndC <>  then

  begin

    SendMessage(hWndC, WM_CAP_FILE_SET_CAPTURE_FILEA, , Longint(pchar(FileName))); // 录成AVI

    Result := SendMessage(hWndC, WM_CAP_SEQUENCE, , ) = ;

  end;

end;

function TUsbCamera.StopRecord: Boolean;

begin

  Result := False;

  if hWndC <>  then Result := SendMessage(hWndC, WM_CAP_STOP, , ) = ;

end;

function TUsbCamera.Stop: boolean;

begin

  Result := False;

  if hWndC <>  then

  begin

    Result := SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, , ) = ; //将捕捉窗同驱动器断开

    FIsOpen := False;

  end;

end;

end.