摄像头编程

这段时间搞视频采集方面的程序，在国外网站上找到一个用C#写的驱动摄像头的程序。

经改造和调试，如下：

安装摄像头后，一般可以找到一个avicap32.dll文件

这是一个关于设想头的类

using System;
using System.Runtime.InteropServices;

namespace webcam
{
?///

?/// avicap 的摘要说明。
?///

?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);
??}
?}

}

具体调用如下：

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using webcam;

namespace webcam
{
?///

?/// Form1 的摘要说明。
?///

?public class Form1 : System.Windows.Forms.Form
?{
??private System.Windows.Forms.Panel panelPreview;
??private System.Windows.Forms.Button b_play;
??private System.Windows.Forms.Button b_stop;
??///

??/// 必需的设计器变量。
??///

??private System.ComponentModel.Container components = null;
??WebCamera wc;

??public Form1()
??{
???//
???// Windows 窗体设计器支持所必需的
???//
???InitializeComponent();

???//
???// TODO: 在 InitializeComponent 调用后添加任何构造函数代码
???//
??}

??///

??/// 清理所有正在使用的资源。
??///

??protected override void Dispose( bool disposing )
??{
???if( disposing )
???{
????if (components != null)
????{
?????components.Dispose();
????}
???}
???base.Dispose( disposing );
??}

??#region Windows 窗体设计器生成的代码
??///

??/// 设计器支持所需的方法 - 不要使用代码编辑器修改
??/// 此方法的内容。
??///

??private void InitializeComponent()
??{
???this.b_play = new System.Windows.Forms.Button();
???this.panelPreview = new System.Windows.Forms.Panel();
???this.b_stop = new System.Windows.Forms.Button();
???this.SuspendLayout();
???//
???// b_play
???//
???this.b_play.Location = new System.Drawing.Point(280, 368);
???this.b_play.Name = "b_play";
???this.b_play.TabIndex = 0;
???this.b_play.Text = "&Play";
???this.b_play.Click += new System.EventHandler(this.button1_Click);
???//
???// panelPreview
???//
???this.panelPreview.Location = new System.Drawing.Point(8, 8);
???this.panelPreview.Name = "panelPreview";
???this.panelPreview.Size = new System.Drawing.Size(344, 272);
???this.panelPreview.TabIndex = 1;
???//
???// b_stop
???//
???this.b_stop.Enabled = false;
???this.b_stop.Location = new System.Drawing.Point(360, 368);
???this.b_stop.Name = "b_stop";
???this.b_stop.TabIndex = 2;
???this.b_stop.Text = "&Stop";
???this.b_stop.Click += new System.EventHandler(this.b_stop_Click);
???//
???// Form1
???//
???this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
???this.ClientSize = new System.Drawing.Size(464, 413);
???this.Controls.Add(this.b_stop);
???this.Controls.Add(this.panelPreview);
???this.Controls.Add(this.b_play);
???this.MaximizeBox = false;
???this.MinimizeBox = false;
???this.Name = "Form1";
???this.Text = "GoodView test Web Camera";
???this.Load += new System.EventHandler(this.Form1_Load);
???this.ResumeLayout(false);

??}
??#endregion

??///

??/// 应用程序的主入口点。
??///

??[STAThread]
??static void Main()
??{
???Application.Run(new Form1());
??}

??private void Form1_Load(object sender, System.EventArgs e)
??{
???b_play.Enabled = false;
???b_stop.Enabled = true;
???panelPreview.Size = new Size(330,330);
???wc = new WebCamera( panelPreview.Handle,panelPreview.Width,panelPreview.Height);
???wc.StartWebCam();
??}

??private void button1_Click(object sender, System.EventArgs e)
??{
???b_play.Enabled = false;
???b_stop.Enabled = true;
???panelPreview.Size = new Size(330,330);
???wc = new WebCamera( panelPreview.Handle,panelPreview.Width,panelPreview.Height);
???wc.StartWebCam();
??}

??private void b_stop_Click(object sender, System.EventArgs e)
??{
???b_play.Enabled = true;
???b_stop.Enabled = false;
???wc.CloseWebcam();
??}
?}
}