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| using System;
using System.Collections;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace WebCamTest
{
public class WebCam : IDisposable
{
private const int WM_CAP = 0x400;
private const int WM_CAP_DRIVER_CONNECT = 0x40a;
private const int WM_CAP_DRIVER_DISCONNECT = 0x40b;
private const int WM_CAP_EDIT_COPY = 0x41e;
private const int WM_CAP_GET_FRAME = 1084;
private const int WM_CAP_COPY = 1054;
private const int WM_CAP_SET_PREVIEW = 0x432;
private const int WM_CAP_SET_OVERLAY = 0x433;
private const int WM_CAP_SET_PREVIEWRATE = 0x434;
private const int WM_CAP_SET_SCALE = 0x435;
private const int WS_CHILD = 0x40000000;
private const int WS_VISIBLE = 0x10000000;
private const int SWP_NOMOVE = 0x2;
private const int SWP_NOZORDER = 0x4;
private const int HWND_BOTTOM = 1;
//This function enables enumerate the web cam devices
[DllImport("avicap32.dll")]
protected static extern bool capGetDriverDescriptionA(short wDriverIndex,
[MarshalAs(UnmanagedType.VBByRefStr)]ref String lpszName,
int cbName, [MarshalAs(UnmanagedType.VBByRefStr)] ref String lpszVer, int cbVer);
//This function enables create a window child with so that you can display it in a picturebox for example
[DllImport("avicap32.dll")]
protected static extern int capCreateCaptureWindowA([MarshalAs(UnmanagedType.VBByRefStr)] ref string lpszWindowName,
int dwStyle, int x, int y, int nWidth, int nHeight, int hWndParent, int nID);
//This function enables set changes to the size, position, and Z order of a child window
[DllImport("user32")]
protected static extern int SetWindowPos(int hwnd, int hWndInsertAfter, int x, int y, int cx, int cy, int wFlags);
//This function enables send the specified message to a window or windows
[DllImport("user32", EntryPoint = "SendMessageA")]
protected static extern int SendMessage(int hwnd, int wMsg, int wParam, [MarshalAs(UnmanagedType.AsAny)] object lParam);
//This function enable destroy the window child
[DllImport("user32")]
protected static extern bool DestroyWindow(int hwnd);
// Normal device ID
int DeviceID = 0;
// Handle value to preview window
int hHwnd = 0;
//The devices list
ArrayList ListOfDevices = new ArrayList();
//The picture to be displayed
public PictureBox Container { get; set; }
// Connect to the device.
/// <summary>
/// This function is used to load the list of the devices
/// </summary>
public void Load()
{
string Name = String.Empty.PadRight(100);
string Version = String.Empty.PadRight(100);
bool moreDevices;
short index = 0;
// Load name of all avialable devices into the lstDevices .
do
{
// Get Driver name and version
moreDevices = capGetDriverDescriptionA(index, ref Name, 100, ref Version, 100);
// If there was a device add device name to the list
if (moreDevices)
ListOfDevices.Add(Name.Trim());
index += 1;
}
while (moreDevices);
}
/// <summary>
/// Function used to display the output from a video capture device, you need to create
/// a capture window.
/// </summary>
public void OpenConnection()
{
string DeviceIndex = Convert.ToString(DeviceID);
IntPtr oHandle = Container.Handle;
// Open Preview window in picturebox .
// Create a child window with capCreateCaptureWindowA so you can display it in a picturebox.
hHwnd = capCreateCaptureWindowA(ref DeviceIndex, WS_VISIBLE | WS_CHILD, 0, 0, 640, 480, oHandle.ToInt32(), 0);
// Connect to device
if (SendMessage(hHwnd, WM_CAP_DRIVER_CONNECT, DeviceID, 0) != 0)
{
// Set the preview scale
SendMessage(hHwnd, WM_CAP_SET_SCALE, -1, 0);
// Set the preview rate in terms of milliseconds
SendMessage(hHwnd, WM_CAP_SET_PREVIEWRATE, 100, 0);
// Start previewing the image from the camera
SendMessage(hHwnd, WM_CAP_SET_PREVIEW, -1, 0);
// Resize window to fit in picturebox
SetWindowPos(hHwnd, HWND_BOTTOM, 0, 0, Container.Width, Container.Height, SWP_NOMOVE | SWP_NOZORDER);
}
else
{
// Error connecting to device close window
DestroyWindow(hHwnd);
}
}
void CloseConnection()
{
SendMessage(hHwnd, WM_CAP_DRIVER_DISCONNECT, DeviceID, 0);
// close window
DestroyWindow(hHwnd);
}
public Bitmap GetCurrentImage()
{
// get the next frame;
SendMessage(hHwnd, WM_CAP_GET_FRAME, 0, 0);
// copy the frame to the clipboard
SendMessage(hHwnd, WM_CAP_COPY, 0, 0);
// Get image from clipboard and convert it to a bitmap
IDataObject data = Clipboard.GetDataObject();
if (data.GetDataPresent(typeof(Bitmap)))
{
var oImage = (Bitmap)data.GetData(typeof(Bitmap));
Container.Image = oImage;
return oImage;
}
return null;
}
~WebCam()
{
Dispose(false);
GC.SuppressFinalize(this);
}
public void Dispose()
{
Dispose(true);
}
virtual protected void Dispose(bool disposing)
{
CloseConnection();
}
}
} |
