C#学习笔记——摄像头

界面：

源码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
//添加引用
using System.Runtime.InteropServices;
using System.Drawing.Imaging;

namespace Camera
{
    public partial class FormMain : Form
    {
        WebCamera wc;
        //声明一个API函数 
        [System.Runtime.InteropServices.DllImportAttribute("gdi32.dll")]
        private static extern bool BitBlt(
        IntPtr hdcDest, // 目标 DC的句柄 
        int nXDest,
        int nYDest,
        int nWidth,
        int nHeight,
        IntPtr hdcSrc, // 源DC的句柄 
        int nXSrc,
        int nYSrc,
        System.Int32 dwRop // 光栅的处理数值 
        );

        public FormMain()
       {
            InitializeComponent();
        }

        private void btnPlay_Click(object sender, EventArgs e)
        {
            btnPlay.Enabled = false;
            btnStop.Enabled = true;
            //panelPreview.Size = new Size(330, 330);
            wc = new WebCamera(panelPreview.Handle, panelPreview.Width, panelPreview.Height);
            wc.StartWebCam();
        }

        private void FormMain_Load(object sender, EventArgs e)
        {
            btnPlay.Enabled = false;
            btnStop.Enabled = true;
            //panelPreview.Size = new Size(330, 330);
            wc = new WebCamera(panelPreview.Handle, panelPreview.Width, panelPreview.Height);
            wc.StartWebCam();
        }

        private void btnStop_Click(object sender, EventArgs e)
        {
            btnPlay.Enabled = true;
            btnStop.Enabled = false;
            wc.CloseWebcam();
        }

        private void btnPhoto_Click(object sender, EventArgs e)
        {
            //创建一个以当前控件区域屏幕为模板的图象 
            Graphics gPanel = this.panelPreview.CreateGraphics();

            Bitmap bmSave = new Bitmap(this.panelPreview.Width, this.panelPreview.Height); //用于保存图片的位图对象

            Graphics gSave = Graphics.FromImage(bmSave);

            //得到屏幕的DC 
            IntPtr dcPanel = gPanel.GetHdc();
            //得到Bitmap的DC 
            IntPtr dcSave = gSave.GetHdc();
            //调用此API函数，实现屏幕捕获 
            BitBlt(dcSave, 0, 0, this.panelPreview.Width, this.panelPreview.Height, dcPanel, 0, 0, 13369376);
            //释放掉屏幕的DC 
            gPanel.ReleaseHdc(dcPanel);
            //释放掉Bitmap的DC 
            gSave.ReleaseHdc(dcSave);
            //以JPG文件格式来保存 
            bmSave.Save(@"D:/Photo.jpg", ImageFormat.Jpeg);
            MessageBox.Show("当前图像已经保存为D盘Photo文件！");
        }
    }

    //show Video class
    public class showVideo
    {

        // showVideo calls
        [DllImport("avicap32.dll")]
        public static extern IntPtr capCreateCaptureWindowA(byte[] lpszWindowName, int dwStyle, int x, int y, int nWidth, int nHeight, IntPtr hWndParent, int nID);
        [DllImport("avicap32.dll")]
        public static extern bool capGetDriverDescriptionA(short wDriver, byte[] lpszName, int cbName, byte[] lpszVer, int cbVer);
        [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, short wParam, FrameEventHandler lParam);
        [DllImport("User32.dll")]
        public static extern bool SendMessage(IntPtr hWnd, int wMsg, int wParam, ref BITMAPINFO lParam);
        [DllImport("User32.dll")]
        public static extern int SetWindowPos(IntPtr hWnd, int hWndInsertAfter, int x, int y, int cx, int cy, int wFlags);
        [DllImport("avicap32.dll")]
        public static extern int capGetVideoFormat(IntPtr hWnd, IntPtr psVideoFormat, int wSize);

        // Constants
        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;

        // Structures
        [StructLayout(LayoutKind.Sequential)]
        public struct VIDEOHDR
        {
            [MarshalAs(UnmanagedType.I4)]
            public int lpData;

            [MarshalAs(UnmanagedType.I4)]
            public int dwBufferLength;

            [MarshalAs(UnmanagedType.I4)]
            public int dwBytesUsed;

            [MarshalAs(UnmanagedType.I4)]
            public int dwTimeCaptured;

            [MarshalAs(UnmanagedType.I4)]
            public int dwUser;

            [MarshalAs(UnmanagedType.I4)]
            public int dwFlags;

            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]
            public int[] dwReserved;

        }

        [StructLayout(LayoutKind.Sequential)]
        public struct BITMAPINFOHEADER
        {

            [MarshalAs(UnmanagedType.I4)]
            public Int32 biSize;

            [MarshalAs(UnmanagedType.I4)]
            public Int32 biWidth;

            [MarshalAs(UnmanagedType.I4)]
            public Int32 biHeight;

            [MarshalAs(UnmanagedType.I2)]
            public short biPlanes;

            [MarshalAs(UnmanagedType.I2)]
            public short biBitCount;

            [MarshalAs(UnmanagedType.I4)]
            public Int32 biCompression;

            [MarshalAs(UnmanagedType.I4)]
            public Int32 biSizeImage;

            [MarshalAs(UnmanagedType.I4)]
            public Int32 biXPelsPerMeter;

            [MarshalAs(UnmanagedType.I4)]
            public Int32 biYPelsPerMeter;

            [MarshalAs(UnmanagedType.I4)]
            public Int32 biClrUsed;

            [MarshalAs(UnmanagedType.I4)]
            public Int32 biClrImportant;

        }



        [StructLayout(LayoutKind.Sequential)]
        public struct BITMAPINFO
        {

            [MarshalAs(UnmanagedType.Struct, SizeConst = 40)]
            public BITMAPINFOHEADER bmiHeader;

            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1024)]
            public Int32[] bmiColors;

        }



        public delegate void FrameEventHandler(IntPtr lwnd, IntPtr lpVHdr);



        // Public methods

        public static object GetStructure(IntPtr ptr, ValueType structure)
        {

            return Marshal.PtrToStructure(ptr, structure.GetType());

        }



        public static object GetStructure(int ptr, ValueType structure)
        {

            return GetStructure(new IntPtr(ptr), structure);

        }



        public static void Copy(IntPtr ptr, byte[] data)
        {

            Marshal.Copy(ptr, data, 0, data.Length);

        }



        public static void Copy(int ptr, byte[] data)
        {

            Copy(new IntPtr(ptr), data);

        }



        public static int SizeOf(object structure)
        {

            return Marshal.SizeOf(structure);

        }

    }



    //Web Camera Class

    public class WebCamera
    {

        // Constructur

        public WebCamera(IntPtr handle, int width, int height)
        {

            mControlPtr = handle;

            mWidth = width;

            mHeight = height;

        }



        // delegate for frame callback

        public delegate void RecievedFrameEventHandler(byte[] data);

        public event RecievedFrameEventHandler RecievedFrame;



        private IntPtr lwndC; // Holds the unmanaged handle of the control

        private IntPtr mControlPtr; // Holds the managed pointer of the control

        private int mWidth;

        private int mHeight;



        private showVideo.FrameEventHandler mFrameEventHandler; // Delegate instance for the frame callback - must keep alive! gc should NOT collect it



        // Close the web camera

        public void CloseWebcam()
        {

            this.capDriverDisconnect(this.lwndC);

        }



        // start the web camera

        public void StartWebCam()
        {

            byte[] lpszName = new byte[100];

            byte[] lpszVer = new byte[100];



            showVideo.capGetDriverDescriptionA(0, lpszName, 100, lpszVer, 100);

            this.lwndC = showVideo.capCreateCaptureWindowA(lpszName, showVideo.WS_VISIBLE + showVideo.WS_CHILD, 0, 0, mWidth, mHeight, mControlPtr, 0);



            if (this.capDriverConnect(this.lwndC, 0))
            {

                this.capPreviewRate(this.lwndC, 66);

                this.capPreview(this.lwndC, true);

                showVideo.BITMAPINFO bitmapinfo = new showVideo.BITMAPINFO();

                bitmapinfo.bmiHeader.biSize = showVideo.SizeOf(bitmapinfo.bmiHeader);

                bitmapinfo.bmiHeader.biWidth = 352;

                bitmapinfo.bmiHeader.biHeight = 288;

                bitmapinfo.bmiHeader.biPlanes = 1;

                bitmapinfo.bmiHeader.biBitCount = 24;

                this.capSetVideoFormat(this.lwndC, ref bitmapinfo, showVideo.SizeOf(bitmapinfo));

                this.mFrameEventHandler = new showVideo.FrameEventHandler(FrameCallBack);

                this.capSetCallbackOnFrame(this.lwndC, this.mFrameEventHandler);

                showVideo.SetWindowPos(this.lwndC, 0, 0, 0, mWidth, mHeight, 6);

            }

        }



        // private functions

        private bool capDriverConnect(IntPtr lwnd, short i)
        {

            return showVideo.SendMessage(lwnd, showVideo.WM_CAP_DRIVER_CONNECT, i, 0);

        }



        private bool capDriverDisconnect(IntPtr lwnd)
        {

            return showVideo.SendMessage(lwnd, showVideo.WM_CAP_DRIVER_DISCONNECT, 0, 0);

        }



        private bool capPreview(IntPtr lwnd, bool f)
        {

            return showVideo.SendMessage(lwnd, showVideo.WM_CAP_SET_PREVIEW, f, 0);

        }



        private bool capPreviewRate(IntPtr lwnd, short wMS)
        {

            return showVideo.SendMessage(lwnd, showVideo.WM_CAP_SET_PREVIEWRATE, wMS, 0);

        }



        private bool capSetCallbackOnFrame(IntPtr lwnd, showVideo.FrameEventHandler lpProc)
        {

            return showVideo.SendMessage(lwnd, showVideo.WM_CAP_SET_CALLBACK_FRAME, 0, lpProc);

        }



        private bool capSetVideoFormat(IntPtr hCapWnd, ref showVideo.BITMAPINFO BmpFormat, int CapFormatSize)
        {

            return showVideo.SendMessage(hCapWnd, showVideo.WM_CAP_SET_VIDEOFORMAT, CapFormatSize, ref BmpFormat);

        }



        private void FrameCallBack(IntPtr lwnd, IntPtr lpVHdr)
        {

            showVideo.VIDEOHDR videoHeader = new showVideo.VIDEOHDR();

            byte[] VideoData;

            videoHeader = (showVideo.VIDEOHDR)showVideo.GetStructure(lpVHdr, videoHeader);

            VideoData = new byte[videoHeader.dwBytesUsed];

            showVideo.Copy(videoHeader.lpData, VideoData);

            if (this.RecievedFrame != null)

                this.RecievedFrame(VideoData);

        }

    }



}