WebCamera #2
The WebCamera class make use of an API32 Wrapper Class which contains all the API calls and constants.
WARNING: You MUST keep the instance, otherwise it will be GC and the API32 calls will fail to callback)
How to use syntax:
Decleration and instance of WebCamera.
WebCamera
wc = new WebCamera(this.Handle, this.Width, this.Height);
Handle the ReceivedFrame Event
wc.RecievedFrame+=new WebCamera.RecievedFrameEventHandler(wc_RecievedFrame);
void
wc_RecievedFrame(object o , WebCameraEventArgs e)
{
//throw new NotImplementedException();
}
API32 Wrapper Class
using System.Runtime.InteropServices;
public class API32
{
// API32 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(object sender,WebCameraEventArgs e);
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 API32.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];
API32.capGetDriverDescriptionA(0, lpszName, 100, lpszVer, 100);
this.lwndC = API32.capCreateCaptureWindowA(lpszName, API32.WS_VISIBLE + API32.WS_CHILD, 0, 0, mWidth, mHeight, mControlPtr, 0);
if (this.capDriverConnect(this.lwndC, 0))
{
this.capPreviewRate(this.lwndC, 66);
this.capPreview(this.lwndC, true);
API32.BITMAPINFO bitmapinfo = new API32.BITMAPINFO();
bitmapinfo.bmiHeader.biSize =
API32.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, API32.SizeOf(bitmapinfo));
this.mFrameEventHandler = new API32.FrameEventHandler(FrameCallBack);
this.capSetCallbackOnFrame(this.lwndC, this.mFrameEventHandler);
API32.SetWindowPos(this.lwndC, 0, 0, 0, mWidth, mHeight, 6);
}
}
// private functions
private bool capDriverConnect(IntPtr lwnd, short i)
{
return API32.SendMessage(lwnd, API32.WM_CAP_DRIVER_CONNECT, i, 0);
}
private bool capDriverDisconnect(IntPtr lwnd)
{
return API32.SendMessage(lwnd, API32.WM_CAP_DRIVER_DISCONNECT, 0, 0);
}
private bool capPreview(IntPtr lwnd, bool f)
{
return API32.SendMessage(lwnd, API32.WM_CAP_SET_PREVIEW, f, 0);
}
private bool capPreviewRate(IntPtr lwnd, short wMS)
{
return API32.SendMessage(lwnd, API32.WM_CAP_SET_PREVIEWRATE, wMS, 0);
}
private bool capSetCallbackOnFrame(IntPtr lwnd, API32.FrameEventHandler lpProc)
{
return API32.SendMessage(lwnd, API32.WM_CAP_SET_CALLBACK_FRAME, 0, lpProc);
}
private bool capSetVideoFormat(IntPtr hCapWnd, ref API32.BITMAPINFO BmpFormat, int CapFormatSize)
{
return API32.SendMessage(hCapWnd, API32.WM_CAP_SET_VIDEOFORMAT, CapFormatSize, ref BmpFormat);
}
private void FrameCallBack(IntPtr lwnd, IntPtr lpVHdr)
{
API32.VIDEOHDR videoHeader = new API32.VIDEOHDR();
byte[] VideoData;
videoHeader = (
API32.VIDEOHDR)API32.GetStructure(lpVHdr, videoHeader);
VideoData =
new byte[videoHeader.dwBytesUsed];
API32.Copy(videoHeader.lpData, VideoData);
System.Drawing.
Bitmap bmp = new Bitmap(352, 288);
System.Drawing.Imaging.
BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0, 352, 288), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
// Copy the data from memory to the Scan0 property of our Bitmap
for (int i = 0; i < VideoData.Length; i++)
Marshal.WriteByte(bmpData.Scan0 , i,VideoData[i]);
bmp.UnlockBits(bmpData);
if (this.RecievedFrame != null)
{
WebCameraEventArgs e = new WebCameraEventArgs(VideoData, bmp);
this.RecievedFrame(this,e);
}
}
}
Web Camera Event Args Class
public
class WebCameraEventArgs : EventArgs
{
private System.Drawing.Bitmap bitMap;
private byte[] data;
public WebCameraEventArgs(byte[] videoData, System.Drawing.Bitmap bmp)
{
data = videoData;
bitMap = bmp;
}
public byte[] Data
{
get
{
return data;
}
}
public System.Drawing.Bitmap Bitmap
{
get
{
return bitMap;
}
}
}