写了一个DELPHI操作USB摄像头类分享给大家

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

{*******************************************************}{                                                       }{       操作USB摄像头类                                 }{                                                       }{       作者：lqen                                      }{       日期：2015.05.18                                }{                                                       }{*******************************************************}unit untUsbCamera;interfaceuses  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 + 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;const WM_CAP_DLG_VIDEODISPLAY = WM_CAP_START + 41; //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, 1, Length(BmpPath) - 3) + 'jpg');    Result := Copy(BmpPath, 1, Length(BmpPath) - 3) + '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, 0, 0, bbmp.Width, bbmp.Height, abmp.Canvas.Handle, 0, 0, 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 <> 0 then  begin    ForceDirectories(ExtractFilePath(FileName));    if SendMessage(hWndC, WM_CAP_SAVEDIB, 0, longint(pchar(FileName))) <> 1 then exit; //截图    if FileExists(FileName) then    begin      Image_FitBitmap(FileName, FileName, 400, 400);      FileName := BmpToJpg(FileName);      Result := True;    end;  end;end;constructor TUsbCamera.Create();beginend;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    0, //X坐标    0, //Y坐标    FPanel.Width, //窗口宽    FPanel.Height, //窗口高    FPanel.Handle, //窗口句柄    0); //一般为0  if hWndC <> 0 then  begin    if SendMessage(hWndC, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, 0) <> 1 then exit;    //捕捉一个视频流    if SendMessage(hWndC, WM_CAP_SET_CALLBACK_ERROR, 0, 0) <> 1 then exit; //得到一个设备错误    if SendMessage(hWndC, WM_CAP_SET_CALLBACK_STATUSA, 0, 0) <> 1 then exit; //得到一个设备状态    if SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0) <> 1 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, 1, 0) <> 1 then exit;    if SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, 66, 0) <> 1 then exit;    SendMessage(hWndC, WM_CAP_SET_OVERLAY, 1, 0);    if SendMessage(hWndC, WM_CAP_SET_PREVIEW, 1, 0) <> 1 then exit;    Result := True;    FIsOpen := True;  end;end;function TUsbCamera.StartRecord(FileName: string): Boolean;begin  Result := False;  if hWndC <> 0 then  begin    SendMessage(hWndC, WM_CAP_FILE_SET_CAPTURE_FILEA, 0, Longint(pchar(FileName))); // 录成AVI    Result := SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0) = 1;  end;end;function TUsbCamera.StopRecord: Boolean;begin  Result := False;  if hWndC <> 0 then Result := SendMessage(hWndC, WM_CAP_STOP, 0, 0) = 1;end;function TUsbCamera.Stop: boolean;begin  Result := False;  if hWndC <> 0 then  begin    Result := SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0) = 1; //将捕捉窗同驱动器断开    FIsOpen := False;  end;end;end.