摄像头编程
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();
}
}
}