C#利用VFW实现摄像头程序

最近在搞这个考试监控，找来VFW的资料，胡编乱凑而成。

VFW全称为Video for Windows，是微软提供的，内嵌windows系统。

首先定义一个VideoAPI类。

首先调用avicap32.dll

        [DllImport("avicap32.dll")]
        public static extern IntPtr capCreateCaptureWindow(byte[] strWindowName, int dwStyle, int x, int y, int width, int height, IntPtr hwdParent, int nID);

        [DllImport("avicap32.dll")]
        public static extern bool capGetDriverDescription(short wDriver, byte[] lpszName, int cbName, byte[] lpszVer, int cbVer);

再调用User32.dll

        [DllImport("User32.dll")]
        public static extern bool SendMessage(IntPtr hWnd, int wMsg, bool wParam, int lParam);

        [DllImport("User32.dll")]
        public static extern bool SendMessage(IntPtr hWnd, int wMsg, short wParam, int lParam);

        [DllImport("User32.dll")]
        public static extern bool SendMessage(IntPtr hWnd, int wMsg, int wParam, string lParam);

再定义一堆消息。

        //常量
        public const int WM_USER = 0x400; 
        public const int WS_CHILD = 0x40000000; 
        public const int WS_VISIBLE = 0x10000000; 
        public const int SWP_NOMOVE = 0x2; 
        public const int SWP_NOZORDER = 0x4;  
        public const int WM_CAP_DRIVER_CONNECT = WM_USER + 10; 
        public const int WM_CAP_DRIVER_DISCONNECT = WM_USER + 11; 
        public const int WM_CAP_SET_CALLBACK_FRAME = WM_USER + 5; 
        public const int WM_CAP_SET_PREVIEW = WM_USER + 50; 
        public const int WM_CAP_SET_PREVIEWRATE = WM_USER + 52; 
        public const int WM_CAP_SET_VIDEOFORMAT = WM_USER + 45; 
        public const int WM_CAP_START = WM_USER;  
        public const int WM_CAP_SAVEDIB = WM_CAP_START + 25;
        public const int WM_CAP_SET_SCALE = WM_USER + 53;
        public const int WM_COPYTOCLIPBORAD = WM_USER + 30;
        public const int WM_CAP_SEQUENCE = WM_USER + 62;
        public const int WM_CAP_FILE_SET_CAPTURE_FILE = WM_USER + 20;
        public const int WM_CAP_STOP = WM_USER + 68;

定义一个VideoClass，用于调用API，启动摄像头，关闭摄像头，保存图片等。

启动摄像头：

        public bool StartWebcam()
        {
            byte[] lpszName = new byte[100];
            byte[] lpszVer = new byte[100];
            VideoAPI.capGetDriverDescription(0, lpszName, 100, lpszVer, 100);

            caphwnd = VideoAPI.capCreateCaptureWindow(lpszName, VideoAPI.WS_CHILD | VideoAPI.WS_VISIBLE, 0, 0, this.width, this.height, this.controlhwnd, 1);

            if (caphwnd == null)
            {
                return false;
            }

            bool isconnect = VideoAPI.SendMessage(caphwnd,VideoAPI.WM_CAP_DRIVER_CONNECT,0,0);
            if(isconnect == false)
            {
                VideoAPI.CloseHandle(caphwnd);
                return false;
            }

            if (VideoAPI.SendMessage(caphwnd, VideoAPI.WM_CAP_SET_PREVIEWRATE, 66, 0) == false)
            {
                return false;
            }

            if (VideoAPI.SendMessage(caphwnd, VideoAPI.WM_CAP_SET_PREVIEW, true, 0) == false)
            {
                return false;
            }

            if (VideoAPI.SendMessage(caphwnd, VideoAPI.WM_CAP_SET_SCALE, 1, 0) == false)
            {
                return false;
            }

            isstart = true;
            return true;
        }

关闭摄像头：

        /// <summary>
        /// 关闭视频设备
        /// </summary>
        /// <returns></returns>
        public bool StopWebcam()
        {
            if (caphwnd != null)
            {
                isstart = false;
                return VideoAPI.SendMessage(caphwnd, VideoAPI.WM_CAP_DRIVER_DISCONNECT, 0, 0);
            }
            else
                return false;
        }

截图：

        public bool GrabImage(IntPtr hWndC, string path)
        {
            if (caphwnd != null)
                return VideoAPI.SendMessage(caphwnd, VideoAPI.WM_CAP_SAVEDIB, 0, path);
            else
                return false;
        }

        public bool SaveImage(string path)
        {
            return GrabImage(this.caphwnd, path);
        }

截图并转换为jpg：

        public void CopyToClipBorad()
        {
            VideoAPI.SendMessage(caphwnd, VideoAPI.WM_COPYTOCLIPBORAD, 0, 0);
        }

        public System.Drawing.Image getCaptureImage()
        {
            System.Windows.Forms.IDataObject iData = System.Windows.Forms.Clipboard.GetDataObject();
            System.Drawing.Image retImage = null;
            if (iData != null)
            {
                if (iData.GetDataPresent(System.Windows.Forms.DataFormats.Bitmap))
                {
                    retImage = (System.Drawing.Image)iData.GetData(System.Windows.Forms.DataFormats.Bitmap);
                }
                else if (iData.GetDataPresent(System.Windows.Forms.DataFormats.Dib))
                {
                    retImage = (System.Drawing.Image)iData.GetData(System.Windows.Forms.DataFormats.Dib);
                }
            }
            return retImage;
        }

在调用类中写：

        public void capture(string strname)
        {
            vc.CopyToClipBorad();
            System.Drawing.Image img = vc.getCaptureImage();
            img.Save(strname, System.Drawing.Imaging.ImageFormat.Jpeg);
        }

 附上视频类和控件：http://files.cnblogs.com/qiu2013/MyWebcam.zip