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Delphi - 利用DLL编程控制摄像头实现拍照、录制视频

作者:admin 来源: 日期:2019/10/11 10:42:33 人气: 标签:

 
Delphi利用avicap32.dll编程控制摄像头实现拍照、录制视频

项目需求:平板电脑(Windows系统)一维/二维码扫描功能;

需求分析:

需要扫描一维/二维码时,分两步实现。

第一步,avicap32.dll或者dspack技术实现静默打开摄像头拍照、保存BMP图片。

第二步,ZXing技术实现对一维/二维码的解析,最终获取到码值。

本篇是利用avicap32.dll技术实现拍照/录制视频的测试Demo。

请看代码:
unit uMain;

interface

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

type
  TFrmMain = class(TForm)
    gbScreen: TRzGroupBox;
    gbOperation: TRzGroupBox;
    btnStart: TRzBitBtn;
    btnStop: TRzBitBtn;
    btnSaveBMP: TRzBitBtn;
    btnStartR: TRzBitBtn;
    btnSaveAVI: TRzBitBtn;
    pMain: TPanel;
    procedure btnStartClick(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure btnStopClick(Sender: TObject);
    procedure btnSaveBMPClick(Sender: TObject);
    procedure btnStartRClick(Sender: TObject);
    procedure btnSaveAVIClick(Sender: TObject);
  private
    { Private declarations }
    hWndC: THandle;
  public
    { Public declarations }
  end;

var
  FrmMain: TFrmMain;
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 TFrmMain.btnStartClick(Sender: TObject);
begin
  //开始拍摄
  hWndC := capCreateCaptureWindowA('My Own Capture Window', WS_CHILD or WS_VISIBLE, pMain.Left, pMain.Top, pMain.Width, pMain.Height, FrmMain.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 TFrmMain.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  //程序退出时,自动关闭摄像头
  if hWndC <> 0 then
  begin
    SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
  end;
end;

procedure TFrmMain.btnStopClick(Sender: TObject);
begin
  //关闭摄像头
  if hWndC <> 0 then
  begin
    SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
    hWndC := 0;
  end;
end;

procedure TFrmMain.btnSaveBMPClick(Sender: TObject);
begin
  //保存BMP
  if hWndC <> 0 then
  begin
    SendMessage(hWndC, WM_CAP_SAVEDIB, 0, longint(pchar('D:/1.bmp')));
  end;
end;

procedure TFrmMain.btnStartRClick(Sender: TObject);
begin
  //开始录制AVI视频
  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 TFrmMain.btnSaveAVIClick(Sender: TObject);
begin
  //停止录制并保存AVI视频
  if hWndC <> 0 then
  begin
    SendMessage(hWndC, WM_CAP_STOP, 0, 0);
  end;
end;

end.