C# 如何在不使用剪贴板的情况下复制图像？
问题：我有下面的代码从网络摄像头捕获图像 我的问题是这一部分：C# 如何在不使用剪贴板的情况下复制图像？,c#,winapi,video,webcam,vfw,C#,Winapi,Video,Webcam,Vfw,问题：我有下面的代码从网络摄像头捕获图像 我的问题是这一部分： SendMessage(hCaptureWnd, WM_CAP_COPY, 0, 0); // copy it to the clipboard 它所做的是将图像从窗口复制到剪贴板，然后从中创建一个字节数组 它可以工作-只要在程序运行时不使用剪贴板。 问题是，这甚至对我自己都不起作用，因为我有时会复制一些东西，而VisualStudio需要很长时间才能开始调试web应用程序，然后它就会崩溃 所
SendMessage(hCaptureWnd, WM_CAP_COPY, 0, 0); // copy it to the clipboard
问题是，这甚至对我自己都不起作用，因为我有时会复制一些东西，而VisualStudio需要很长时间才能开始调试web应用程序，然后它就会崩溃 所以我的问题是：
如何在不使用剪贴板的情况下获取图像？ 或者更具体地说，如何将hCaptureWnd转换为System.Drawing.Image
--编辑：
我没有说“不创建文件，我想要一个字节数组”。
它是一个web应用程序，因此运行该应用程序的用户不应具有对文件系统的写入权限（写入文件仅用于临时测试）…
--结束编辑：
完整代码供参考
using System;
using System.IO;
using System.Drawing;
using System.Threading;
using System.Windows.Forms;
using System.Drawing.Imaging;
using System.Collections.Generic;
using System.Runtime.InteropServices;
// http://www.creativecodedesign.com/node/66
// http://www.barebonescoder.com/2012/01/finding-your-web-cam-with-c-directshow-net/
// http://www.codeproject.com/Articles/15219/WebCam-Fast-Image-Capture-Service-using-WIA
// http://www.c-sharpcorner.com/uploadfile/yougerthen/integrate-the-web-webcam-functionality-using-C-Sharp-net-and-com-part-viii/
// http://forums.asp.net/t/1410057.aspx
namespace cc.Utility
{
// bool isCaptured = ccWebCam.CaptureSTA("capture.jpg"); // Access to path C:\Program Files (x86)\Common Files\Microsoft Shared\DevServer\10.0\capture.jpg" denied.
// byte[] captureBytes = ccWebCam.CaptureSTA();
/// <summary>
/// Timur Kovalev (http://www.creativecodedesign.com):
/// This class provides a method of capturing a webcam image via avicap32.dll api.
/// </summary>
public static class ccWebCam
{
#region *** PInvoke Stuff - methods to interact with capture window ***
[DllImport("user32", EntryPoint = "SendMessage")]
private static extern int SendMessage(int hWnd, uint Msg, int wParam, int lParam);
[DllImport("avicap32.dll", EntryPoint = "capCreateCaptureWindowA")]
private static extern int capCreateCaptureWindowA(string lpszWindowName, int dwStyle,
int X, int Y, int nWidth, int nHeight, int hwndParent, int nID);
private const int WM_CAP_CONNECT = 1034;
private const int WM_CAP_DISCONNECT = 1035;
private const int WM_CAP_COPY = 1054;
private const int WM_CAP_GET_FRAME = 1084;
#endregion
private static object objWebCamThreadLock = new object();
//CaptureToFile(@"D:\Stefan.Steiger\Documents\Visual Studio 2010\Projects\Post_Ipag\image3.jpg"):
public static bool Capture(string filePath, int connectDelay = 500)
{
lock (objWebCamThreadLock)
{
return cc.Utility.ccWebCam.InternalCaptureAsFileInThread(filePath, connectDelay);
}
} // End Treadsafe Function Capture
public static byte[] Capture(int connectDelay = 500)
{
lock (objWebCamThreadLock)
{
return InternalCaptureToByteArrayInThread(connectDelay);
}
} // End Treadsafe Function Capture
/// <summary>
/// Captures a frame from the webcam and returns the byte array associated
/// with the captured image. The image is also stored in a file
/// </summary>
/// <param name="filePath">path the file wher ethe image will be saved</param>
/// <param name="connectDelay">number of milliseconds to wait between connect
/// and capture - necessary for some cameras that take a while to 'warm up'</param>
/// <returns>true on success, false on failure</returns>
private static bool InternalCaptureAsFileInThread(string filePath, int connectDelay = 500)
{
bool success = false;
Thread catureThread = new Thread(() =>
{
success = InternalCaptureAsFile(filePath, connectDelay);
});
catureThread.SetApartmentState(ApartmentState.STA);
catureThread.Start();
catureThread.Join();
return success;
} // End Function InternalCaptureAsFileInThread
/// <summary>
/// Captures a frame from the webcam and returns the byte array associated
/// with the captured image. The image is also stored in a file
/// </summary>
/// <param name="filePath">path the file wher ethe image will be saved</param>
/// <param name="connectDelay">number of milliseconds to wait between connect
/// and capture - necessary for some cameras that take a while to 'warm up'</param>
/// <returns>true on success, false on failure</returns>
private static bool InternalCaptureAsFile(string filePath, int connectDelay = 500)
{
byte[] capture = ccWebCam.InternalCaptureToByteArray(connectDelay);
if (capture != null)
{
// Access to path C:\Program Files (x86)\Common Files\Microsoft Shared\DevServer\10.0\image1.jpg" denied.
File.WriteAllBytes(filePath, capture);
return true;
}
return false;
} // End Function InternalCaptureAsFile
/// <summary>
/// Captures a frame from the webcam and returns the byte array associated
/// with the captured image. Runs in a newly-created STA thread which is
/// required for this method of capture
/// </summary>
/// <param name="connectDelay">number of milliseconds to wait between connect
/// and capture - necessary for some cameras that take a while to 'warm up'</param>
/// <returns>byte array representing a bitmp or null (if error or no webcam)</returns>
private static byte[] InternalCaptureToByteArrayInThread(int connectDelay = 500)
{
byte[] bytes = null;
Thread catureThread = new Thread(() =>
{
bytes = InternalCaptureToByteArray(connectDelay);
});
catureThread.SetApartmentState(ApartmentState.STA);
catureThread.Start();
catureThread.Join();
return bytes;
} // End Function InternalCaptureToByteArrayInThread
/// <summary>
/// Captures a frame from the webcam and returns the byte array associated
/// with the captured image
/// </summary>
/// <param name="connectDelay">number of milliseconds to wait between connect
/// and capture - necessary for some cameras that take a while to 'warm up'</param>
/// <returns>byte array representing a bitmp or null (if error or no webcam)</returns>
private static byte[] InternalCaptureToByteArray(int connectDelay = 500)
{
Clipboard.Clear(); // clear the clipboard
int hCaptureWnd = capCreateCaptureWindowA("ccWebCam", 0, 0, 0, // create the hidden capture window
350, 350, 0, 0);
SendMessage(hCaptureWnd, WM_CAP_CONNECT, 0, 0); // send the connect message to it
Thread.Sleep(connectDelay); // sleep the specified time
SendMessage(hCaptureWnd, WM_CAP_GET_FRAME, 0, 0); // capture the frame
SendMessage(hCaptureWnd, WM_CAP_COPY, 0, 0); // copy it to the clipboard
SendMessage(hCaptureWnd, WM_CAP_DISCONNECT, 0, 0); // disconnect from the camera
Bitmap bitmap = (Bitmap)Clipboard.GetDataObject().GetData(DataFormats.Bitmap); // copy into bitmap
if (bitmap == null)
return null;
using (MemoryStream stream = new MemoryStream())
{
bitmap.Save(stream, ImageFormat.Bmp); // get bitmap bytes
return stream.ToArray();
} // End Using stream
} // End Function InternalCaptureToByteArray
}
}
您必须发送不同的消息，特别是
WM\u CAP\u FILE\u SAVEDIB位图没有什么东西像是
WM\u CAP\u GET\u FRAME同样，这个API对于视频捕获来说是一个不幸的选择。太旧，太有限。根据罗曼·R.的答案： 道德的精妙之处在于，您需要注册回调帧，然后调用grabframe， 您不能直接将C-style char[]强制转换为byte[]，并且您得到的是原始位图数据，而不是位图，并且无论capCreateCaptureWindowA中设置了什么，图像大小都是640x480，并且lpData需要是IntPtr，而不是UIntPtr，因为Marshal.Copy对UIntPtr没有重载，并且使用WriteBitmapFile，可以在不使用不安全代码或映射位图文件头的情况下将原始位图数据写入位图，并且编写Marshal.Copy的人可以复制负值，因为长度是int，而不是uint 此外，无论出于何种原因，都需要将图像旋转180度……
此外，我还将WM常量更改为正确的名称
SendMessage(hCaptureWnd, WM_CAP_SET_CALLBACK_FRAME, 0, capVideoStreamCallback);
SendMessage(hCaptureWnd, WM_CAP_GRAB_FRAME, 0, 0); // capture the frame
// http://msdn.microsoft.com/en-us/library/windows/desktop/dd757688(v=vs.85).aspx
[StructLayout(LayoutKind.Sequential)]
private struct VIDEOHDR
{
// http://msdn.microsoft.com/en-us/library/windows/desktop/aa383751(v=vs.85).aspx
// typedef unsigned char BYTE;
// typedef BYTE far *LPBYTE;
// unsigned char* lpData
//public byte[] lpData; // LPBYTE lpData; // Aaargh, invalid cast, not a .NET byte array...
public IntPtr lpData; // LPBYTE lpData;
public UInt32 dwBufferLength; // DWORD dwBufferLength;
public UInt32 dwBytesUsed; // DWORD dwBytesUsed;
public UInt32 dwTimeCaptured; // DWORD dwTimeCaptured;
// typedef ULONG_PTR DWORD_PTR;
// #if defined(_WIN64)
// typedef unsigned __int64 ULONG_PTR;
// #else
// typedef unsigned long ULONG_PTR;
// #endif
public IntPtr dwUser; // DWORD_PTR dwUser;
public UInt32 dwFlags; // DWORD dwFlags;
[System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.ByValArray, SizeConst = 4)]
public System.UIntPtr[] dwReserved; // DWORD_PTR dwReserved[4];
// Does not make a difference
//public System.UIntPtr[] dwReserved = new System.UIntPtr[4]; // DWORD_PTR dwReserved[4];
}
private delegate System.IntPtr capVideoStreamCallback_t(System.UIntPtr hWnd, ref VIDEOHDR lpVHdr);
[DllImport("user32", EntryPoint = "SendMessage")]
private static extern int SendMessage(int hWnd, uint Msg, int wParam, capVideoStreamCallback_t routine);
// http://eris.liralab.it/yarpdoc/vfw__extra__from__wine_8h.html
private const int WM_USER = 0x0400; // 1024
private const int WM_CAP_START = WM_USER;
private const int WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10;
private const int WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11;
private const int WM_CAP_FILE_SAVEDIB = WM_CAP_START + 25;
private const int WM_CAP_SET_CALLBACK_FRAME = WM_CAP_START + 5;
private const int WM_CAP_GRAB_FRAME = WM_CAP_START + 60;
private const int WM_CAP_EDIT_COPY = WM_CAP_START + 30;
// http://lists.ximian.com/pipermail/mono-devel-list/2011-March/037272.html
private static byte[] baSplendidIsolation;
private static System.IntPtr capVideoStreamCallback(System.UIntPtr hWnd, ref VIDEOHDR lpVHdr)
{
//System.Windows.Forms.MessageBox.Show("hello");
//System.Windows.Forms.MessageBox.Show(lpVHdr.dwBufferLength.ToString() + " " + lpVHdr.dwBytesUsed.ToString());
byte[] _imageTemp = new byte[lpVHdr.dwBufferLength];
Marshal.Copy(lpVHdr.lpData, _imageTemp, 0, (int) lpVHdr.dwBufferLength);
//System.IO.File.WriteAllBytes(@"d:\temp\mycbfile.bmp", _imageTemp); // AAaaarg, it's raw bitmap data...
// http://stackoverflow.com/questions/742236/how-to-create-a-bmp-file-from-byte-in-c-sharp
// http://stackoverflow.com/questions/2654480/writing-bmp-image-in-pure-c-c-without-other-libraries
// Tsssss... 350 x 350 was the expected setting, but never mind...
// fortunately alex told me about WM_CAP_FILE_SAVEDIB, so I could compare to the direct output
int width = 640;
int height = 480;
int stride = width*3;
baSplendidIsolation = null;
baSplendidIsolation = WriteBitmapFile(@"d:\temp\mycbfilecc.bmp", width, height, _imageTemp);
/*
unsafe
{
fixed (byte* ptr = _imageTemp)
{
using (Bitmap image = new Bitmap(width, height, stride, PixelFormat.Format24bppRgb, new IntPtr(ptr)))
{
image.Save(@"d:\temp\mycbfile2.bmp");
}
}
}
*/
//var hdr = (Elf32_Phdr)Marshal.PtrToStructure(ptr, typeof(Elf32_Phdr));
return System.IntPtr.Zero;
}
private static byte[] WriteBitmapFile(string filename, int width, int height, byte[] imageData)
{
using (var stream = new MemoryStream(imageData))
using (var bmp = new Bitmap(width, height, PixelFormat.Format24bppRgb))
{
BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0,bmp.Width, bmp.Height)
,ImageLockMode.WriteOnly
,bmp.PixelFormat
);
Marshal.Copy(imageData, 0, bmpData.Scan0, imageData.Length);
bmp.UnlockBits(bmpData);
if (bmp == null)
return null;
bmp.RotateFlip(RotateFlipType.Rotate180FlipNone);
bmp.Save(filename); // For testing only
using (MemoryStream ms = new MemoryStream())
{
bmp.Save(ms, ImageFormat.Png); // get bitmap bytes
return ms.ToArray();
} // End Using stream
}
} // End Function WriteBitmapFile
/// <summary>
/// Captures a frame from the webcam and returns the byte array associated
/// with the captured image
/// </summary>
/// <param name="connectDelay">number of milliseconds to wait between connect
/// and capture - necessary for some cameras that take a while to 'warm up'</param>
/// <returns>byte array representing a bitmp or null (if error or no webcam)</returns>
private static byte[] InternalCaptureToByteArray(int connectDelay = 500)
{
Clipboard.Clear();
int hCaptureWnd = capCreateCaptureWindowA("ccWebCam", 0, 0, 0,
350, 350, 0, 0); // create the hidden capture window
SendMessage(hCaptureWnd, WM_CAP_DRIVER_CONNECT, 0, 0); // send the connect message to it
//SendMessage(hCaptureWnd, WM_CAP_DRIVER_CONNECT, i, 0); // i device number retval != 0 --> valid device_id
Thread.Sleep(connectDelay); // sleep the specified time
SendMessage(hCaptureWnd, WM_CAP_SET_CALLBACK_FRAME, 0, capVideoStreamCallback);
SendMessage(hCaptureWnd, WM_CAP_GRAB_FRAME, 0, 0); // capture the frame
//SendMessage(hCaptureWnd, WM_CAP_FILE_SAVEDIB, 0, "d:\\temp\\testmywebcamimage.bmp");
//ScreenshotWindow(new IntPtr(hCaptureWnd));
//SendMessage(hCaptureWnd, WM_CAP_EDIT_COPY, 0, 0); // copy it to the clipboard
// using (Graphics g2 = Graphics.FromHwnd(new IntPtr(hCaptureWnd)))
SendMessage(hCaptureWnd, WM_CAP_DRIVER_DISCONNECT, 0, 0); // disconnect from the camera
return baSplendidIsolation;
/*
Bitmap bitmap = (Bitmap)Clipboard.GetDataObject().GetData(DataFormats.Bitmap); // copy into bitmap
if (bitmap == null)
return null;
using (MemoryStream stream = new MemoryStream())
{
bitmap.Save(stream, ImageFormat.Bmp); // get bitmap bytes
return stream.ToArray();
} // End Using stream
*/
} // End Function InternalCaptureToByteArray
//http://msdn.microsoft.com/en-us/library/windows/desktop/dd757688（v=vs.85）.aspx
[StructLayout（LayoutKind.Sequential）]
私有结构视频HDR
{
// http://msdn.microsoft.com/en-us/library/windows/desktop/aa383751（v=vs.85）.aspx
//typedef无符号字符字节；
//typedef BYTE far*LPBYTE；
//无符号字符*lpData
//公共字节[]lpData；//LPBYTE lpData；//Aaargh，无效转换，不是.NET字节数组。。。
public IntPtr lpData；//LPBYTE lpData；
公共UInt32 dwBufferLength；//DWORD dwBufferLength；
public UInt32 dwBytesUsed；//DWORD dwBytesUsed；
public UInt32 dwTimeCaptured；//DWORD dwTimeCaptured；
//类型定义ULONG_PTR DWORD_PTR；
//#如果已定义（_WIN64）
//typedef unsigned_uuint64 ULONG_PTR；
//#其他
//typedef无符号长ULONG_PTR；
//#endif
public IntPtr dwUser；//DWORD\u PTR dwUser；
public UInt32 dwFlags；//DWORD dwFlags；
[System.Runtime.InteropServices.Marshallas（System.Runtime.InteropServices.UnmanagedType.ByValArray，SizeConst=4）]
public System.uintpttr[]dwReserved；//DWORD_PTR dwReserved[4]；
//没什么区别
//public System.uintpttr[]dwReserved=new System.uintpttr[4]；//DWORD_PTR dwReserved[4]；
}
私有委托System.IntPtr capVideoStreamCallback_t（System.UIntPtr hWnd，参考VIDEOHDR lpVHdr）；
[DllImport（“user32”，EntryPoint=“SendMessage”）]
私有静态外部int SendMessage（int hWnd、uint Msg、int wParam、capVideoStreamCallback_t例程）；
// http://eris.liralab.it/yarpdoc/vfw__extra__from__wine_8h.html
私有常量int WM_USER=0x0400；//1024
私有常量int WM_CAP_START=WM_USER；
私用const int WM_CAP_DRIVER_CONNECT=WM_CAP_START+10；
专用常数int WM\U CAP\U DRIVER\U DISCONT=WM\U CAP\U START+11；
私有常量int WM_CAP_FILE_SAVEDIB=WM_CAP_START+25；
私有常量int WM_CAP_SET_CALLBACK_FRAME=WM_CAP_START+5；
私有const int WM_CAP_GRAB_FRAME=WM_CAP_START+60；
私有常量int WM_CAP_EDIT_COPY=WM_CAP_START+30；
// http://lists.ximian.com/pipermail/mono-devel-list/2011-March/037272.html
专用静态字节[]隔离；
专用静态System.IntPtr capVideoStreamCallback（System.UINTPTTR hWnd，参考VIDEOHDR lpVHdr）
{
//System.Windows.Forms.MessageBox.Show（“hello”）；
//System.Windows.Forms.MessageBox.Show（lpVHdr.dwBufferLength.ToString（）+“”+lpVHdr.dwBytesUsed.ToString（））；
字节[]_imageTemp=新字节[lpVHdr.dwBufferLength]；
封送处理副本（lpVHdr.lpData，_imageTemp，0，（int）lpVHdr.dwBufferLength）；
//System.IO.File.writealBytes（@“d:\temp\mycbfile.bmp”，_imageTemp）；//AAaaarg，它是原始位图数据。。。
[DllImport("user32.dll")]
static extern IntPtr GetWindowDC(IntPtr hWnd);
[DllImport("gdi32.dll", SetLastError = true)]
static extern IntPtr CreateCompatibleDC(IntPtr hdc);
enum TernaryRasterOperations : uint
{
/// <summary>dest = source</summary>
SRCCOPY = 0x00CC0020,
/// <summary>dest = source OR dest</summary>
SRCPAINT = 0x00EE0086,
/// <summary>dest = source AND dest</summary>
SRCAND = 0x008800C6,
/// <summary>dest = source XOR dest</summary>
SRCINVERT = 0x00660046,
/// <summary>dest = source AND (NOT dest)</summary>
SRCERASE = 0x00440328,
/// <summary>dest = (NOT source)</summary>
NOTSRCCOPY = 0x00330008,
/// <summary>dest = (NOT src) AND (NOT dest)</summary>
NOTSRCERASE = 0x001100A6,
/// <summary>dest = (source AND pattern)</summary>
MERGECOPY = 0x00C000CA,
/// <summary>dest = (NOT source) OR dest</summary>
MERGEPAINT = 0x00BB0226,
/// <summary>dest = pattern</summary>
PATCOPY = 0x00F00021,
/// <summary>dest = DPSnoo</summary>
PATPAINT = 0x00FB0A09,
/// <summary>dest = pattern XOR dest</summary>
PATINVERT = 0x005A0049,
/// <summary>dest = (NOT dest)</summary>
DSTINVERT = 0x00550009,
/// <summary>dest = BLACK</summary>
BLACKNESS = 0x00000042,
/// <summary>dest = WHITE</summary>
WHITENESS = 0x00FF0062,
/// <summary>
/// Capture window as seen on screen. This includes layered windows
/// such as WPF windows with AllowsTransparency="true"
/// </summary>
CAPTUREBLT = 0x40000000
}
[DllImport("gdi32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool BitBlt(IntPtr hdc, int nXDest, int nYDest, int nWidth, int nHeight, IntPtr hdcSrc, int nXSrc, int nYSrc, TernaryRasterOperations dwRop);
[DllImport("gdi32.dll")]
static extern IntPtr CreateCompatibleBitmap(IntPtr hdc, int nWidth, int nHeight);
[DllImport("gdi32.dll", ExactSpelling = true, PreserveSig = true, SetLastError = true)]
static extern IntPtr SelectObject(IntPtr hdc, IntPtr hgdiobj);
[DllImport("gdi32.dll")]
static extern bool DeleteDC(IntPtr hdc);
[DllImport("user32.dll")]
static extern bool ReleaseDC(IntPtr hWnd, IntPtr hDC);
[DllImport("gdi32.dll")]
static extern bool DeleteObject(IntPtr hObject);
public static void ScreenshotWindow(IntPtr windowHandle)
{
Rect Rect = new Rect();
GetWindowRect(windowHandle, ref Rect);
int width = Rect.Right - Rect.Left;
int height = Rect.Bottom - Rect.Top;
IntPtr windowDeviceContext = GetWindowDC(windowHandle);
IntPtr destDeviceContext = CreateCompatibleDC(windowDeviceContext);
IntPtr bitmapHandle = CreateCompatibleBitmap(windowDeviceContext, width, height);
IntPtr oldObject = SelectObject(destDeviceContext, bitmapHandle);
BitBlt(destDeviceContext, 0, 0, width, height, windowDeviceContext, 0, 0, TernaryRasterOperations.CAPTUREBLT | TernaryRasterOperations.SRCCOPY);
SelectObject(destDeviceContext, oldObject);
DeleteDC(destDeviceContext);
ReleaseDC(windowHandle, destDeviceContext);
Image screenshot = Image.FromHbitmap(bitmapHandle);
DeleteObject(bitmapHandle);
screenshot.Save("d:\\temp\\mywebcamimage.png", System.Drawing.Imaging.ImageFormat.Png);
/*
// TODO - Remove above save when it works
using (MemoryStream stream = new MemoryStream())
{
screenshot.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
return stream.ToArray();
}
*/
}
ScreenshotWindow(new IntPtr(hCaptureWnd));
[DllImport("user32", EntryPoint = "SendMessage")]
private static extern int SendMessage(
int hWnd, uint Msg, int wParam, string strFileName);
private const int WM_USER = 0x0400;
private const int WM_CAP_START = WM_USER;
private const int WM_CAP_FILE_SAVEDIB = WM_CAP_START + 25;
//before
SendMessage(hCaptureWnd, WM_CAP_COPY, 0, 0);
//after
string tempFile = Server.MapPath("~/App_Data/tempCap.bmp");
SendMessage(hCaptureWnd, WM_CAP_FILE_SAVEDIB, 0, tempFile); //create tempfile
Bitmap bitmap = new Bitmap(tempFile); //read tempfile
using (MemoryStream stream = new MemoryStream())
{
bitmap.Save(stream, ImageFormat.Bmp);
return stream.ToArray();
}
SendMessage(hCaptureWnd, WM_CAP_SET_CALLBACK_FRAME, 0, capVideoStreamCallback);
SendMessage(hCaptureWnd, WM_CAP_GRAB_FRAME, 0, 0); // capture the frame
// http://msdn.microsoft.com/en-us/library/windows/desktop/dd757688(v=vs.85).aspx
[StructLayout(LayoutKind.Sequential)]
private struct VIDEOHDR
{
// http://msdn.microsoft.com/en-us/library/windows/desktop/aa383751(v=vs.85).aspx
// typedef unsigned char BYTE;
// typedef BYTE far *LPBYTE;
// unsigned char* lpData
//public byte[] lpData; // LPBYTE lpData; // Aaargh, invalid cast, not a .NET byte array...
public IntPtr lpData; // LPBYTE lpData;
public UInt32 dwBufferLength; // DWORD dwBufferLength;
public UInt32 dwBytesUsed; // DWORD dwBytesUsed;
public UInt32 dwTimeCaptured; // DWORD dwTimeCaptured;
// typedef ULONG_PTR DWORD_PTR;
// #if defined(_WIN64)
// typedef unsigned __int64 ULONG_PTR;
// #else
// typedef unsigned long ULONG_PTR;
// #endif
public IntPtr dwUser; // DWORD_PTR dwUser;
public UInt32 dwFlags; // DWORD dwFlags;
[System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.ByValArray, SizeConst = 4)]
public System.UIntPtr[] dwReserved; // DWORD_PTR dwReserved[4];
// Does not make a difference
//public System.UIntPtr[] dwReserved = new System.UIntPtr[4]; // DWORD_PTR dwReserved[4];
}
private delegate System.IntPtr capVideoStreamCallback_t(System.UIntPtr hWnd, ref VIDEOHDR lpVHdr);
[DllImport("user32", EntryPoint = "SendMessage")]
private static extern int SendMessage(int hWnd, uint Msg, int wParam, capVideoStreamCallback_t routine);
// http://eris.liralab.it/yarpdoc/vfw__extra__from__wine_8h.html
private const int WM_USER = 0x0400; // 1024
private const int WM_CAP_START = WM_USER;
private const int WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10;
private const int WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11;
private const int WM_CAP_FILE_SAVEDIB = WM_CAP_START + 25;
private const int WM_CAP_SET_CALLBACK_FRAME = WM_CAP_START + 5;
private const int WM_CAP_GRAB_FRAME = WM_CAP_START + 60;
private const int WM_CAP_EDIT_COPY = WM_CAP_START + 30;
// http://lists.ximian.com/pipermail/mono-devel-list/2011-March/037272.html
private static byte[] baSplendidIsolation;
private static System.IntPtr capVideoStreamCallback(System.UIntPtr hWnd, ref VIDEOHDR lpVHdr)
{
//System.Windows.Forms.MessageBox.Show("hello");
//System.Windows.Forms.MessageBox.Show(lpVHdr.dwBufferLength.ToString() + " " + lpVHdr.dwBytesUsed.ToString());
byte[] _imageTemp = new byte[lpVHdr.dwBufferLength];
Marshal.Copy(lpVHdr.lpData, _imageTemp, 0, (int) lpVHdr.dwBufferLength);
//System.IO.File.WriteAllBytes(@"d:\temp\mycbfile.bmp", _imageTemp); // AAaaarg, it's raw bitmap data...
// http://stackoverflow.com/questions/742236/how-to-create-a-bmp-file-from-byte-in-c-sharp
// http://stackoverflow.com/questions/2654480/writing-bmp-image-in-pure-c-c-without-other-libraries
// Tsssss... 350 x 350 was the expected setting, but never mind...
// fortunately alex told me about WM_CAP_FILE_SAVEDIB, so I could compare to the direct output
int width = 640;
int height = 480;
int stride = width*3;
baSplendidIsolation = null;
baSplendidIsolation = WriteBitmapFile(@"d:\temp\mycbfilecc.bmp", width, height, _imageTemp);
/*
unsafe
{
fixed (byte* ptr = _imageTemp)
{
using (Bitmap image = new Bitmap(width, height, stride, PixelFormat.Format24bppRgb, new IntPtr(ptr)))
{
image.Save(@"d:\temp\mycbfile2.bmp");
}
}
}
*/
//var hdr = (Elf32_Phdr)Marshal.PtrToStructure(ptr, typeof(Elf32_Phdr));
return System.IntPtr.Zero;
}
private static byte[] WriteBitmapFile(string filename, int width, int height, byte[] imageData)
{
using (var stream = new MemoryStream(imageData))
using (var bmp = new Bitmap(width, height, PixelFormat.Format24bppRgb))
{
BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0,bmp.Width, bmp.Height)
,ImageLockMode.WriteOnly
,bmp.PixelFormat
);
Marshal.Copy(imageData, 0, bmpData.Scan0, imageData.Length);
bmp.UnlockBits(bmpData);
if (bmp == null)
return null;
bmp.RotateFlip(RotateFlipType.Rotate180FlipNone);
bmp.Save(filename); // For testing only
using (MemoryStream ms = new MemoryStream())
{
bmp.Save(ms, ImageFormat.Png); // get bitmap bytes
return ms.ToArray();
} // End Using stream
}
} // End Function WriteBitmapFile
/// <summary>
/// Captures a frame from the webcam and returns the byte array associated
/// with the captured image
/// </summary>
/// <param name="connectDelay">number of milliseconds to wait between connect
/// and capture - necessary for some cameras that take a while to 'warm up'</param>
/// <returns>byte array representing a bitmp or null (if error or no webcam)</returns>
private static byte[] InternalCaptureToByteArray(int connectDelay = 500)
{
Clipboard.Clear();
int hCaptureWnd = capCreateCaptureWindowA("ccWebCam", 0, 0, 0,
350, 350, 0, 0); // create the hidden capture window
SendMessage(hCaptureWnd, WM_CAP_DRIVER_CONNECT, 0, 0); // send the connect message to it
//SendMessage(hCaptureWnd, WM_CAP_DRIVER_CONNECT, i, 0); // i device number retval != 0 --> valid device_id
Thread.Sleep(connectDelay); // sleep the specified time
SendMessage(hCaptureWnd, WM_CAP_SET_CALLBACK_FRAME, 0, capVideoStreamCallback);
SendMessage(hCaptureWnd, WM_CAP_GRAB_FRAME, 0, 0); // capture the frame
//SendMessage(hCaptureWnd, WM_CAP_FILE_SAVEDIB, 0, "d:\\temp\\testmywebcamimage.bmp");
//ScreenshotWindow(new IntPtr(hCaptureWnd));
//SendMessage(hCaptureWnd, WM_CAP_EDIT_COPY, 0, 0); // copy it to the clipboard
// using (Graphics g2 = Graphics.FromHwnd(new IntPtr(hCaptureWnd)))
SendMessage(hCaptureWnd, WM_CAP_DRIVER_DISCONNECT, 0, 0); // disconnect from the camera
return baSplendidIsolation;
/*
Bitmap bitmap = (Bitmap)Clipboard.GetDataObject().GetData(DataFormats.Bitmap); // copy into bitmap
if (bitmap == null)
return null;
using (MemoryStream stream = new MemoryStream())
{
bitmap.Save(stream, ImageFormat.Bmp); // get bitmap bytes
return stream.ToArray();
} // End Using stream
*/
} // End Function InternalCaptureToByteArray