/// <summary>
/// Call this method in order to capture a bitmap of the current video window
/// TODO - hook up to a button click event
/// TODO - give the user the ability to provide a file name
/// </summary>
///
/// <remarks>
/// This is the layout in memory, because this is the layout we need
/// on the disk.
///
/// <-------------------------- ptrBlock ----------------------------->
/// <------- ptrImg ------------------------------->
/// | BitmapFileHeader | BitmapInfoHeader | bytes of DIB |
/// </remarks>
private void TakeImage()
{
IBasicVideo iBV = (IBasicVideo)vcg.FilgraphManager;
int len = 0;
// Determine byte count needed to store the Device Independent
// Bitmap (DIB) by calling with a null-pointer
iBV.GetCurrentImage(ref len, IntPtr.Zero);
// Allocate bytes, plus room for a BitmapFileHeader
int sizeOfBFH = Marshal.SizeOf(typeof(BITMAPFILEHEADER));
IntPtr ptrBlock = Marshal.AllocCoTaskMem(len + sizeOfBFH);
IntPtr ptrImg = new IntPtr(ptrBlock.ToInt64() + sizeOfBFH);
try
{
// Get the DIB
iBV.GetCurrentImage(ref len, ptrImg);
// Get a copy of the BITMAPINFOHEADER, to be used in the BITMAPFILEHEADER
BITMAPINFOHEADER bmih = (BITMAPINFOHEADER)Marshal.PtrToStructure(
ptrImg, typeof(BITMAPINFOHEADER));
// Create header for a file of type .bmp
BITMAPFILEHEADER bfh = new BITMAPFILEHEADER();
bfh.Type = (UInt16)((((byte)'M') << 8) | ((byte)'B'));
bfh.Size = (uint)(len + sizeOfBFH);
bfh.Reserved1 = 0;
bfh.Reserved2 = 0;
bfh.OffBits = (uint)(sizeOfBFH + bmih.Size);
// Copy the BFH into unmanaged memory, so that we can copy
// everything into a managed byte array all at once
Marshal.StructureToPtr(bfh, ptrBlock, false);
// Pull it out of unmanaged memory into a managed byte[]
byte[] img = new byte[len + sizeOfBFH];
Marshal.Copy(ptrBlock, img, 0, len + sizeOfBFH);
// Save the DIB to a file
System.IO.File.WriteAllBytes("c:\\cxp.bmp", img);
}
finally
{
// Free the unmanaged memory
if (ptrBlock != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(ptrBlock);
}
}
}
/// <summary>
/// Call this method in order to capture a bitmap of the current video window
/// TODO - hook up to a button click event
/// TODO - give the user the ability to provide a file name
/// </summary>
///
/// <remarks>
/// This is the layout in memory, because this is the layout we need
/// on the disk.
///
/// <-------------------------- ptrBlock ----------------------------->
/// <------- ptrImg ------------------------------->
/// | BitmapFileHeader | BitmapInfoHeader | bytes of DIB |
/// </remarks>
private void TakeImage()
{
IBasicVideo iBV = (IBasicVideo)vcg.FilgraphManager;
int len = 0;
// Determine byte count needed to store the Device Independent
// Bitmap (DIB) by calling with a null-pointer
iBV.GetCurrentImage(ref len, IntPtr.Zero);
// Allocate bytes, plus room for a BitmapFileHeader
int sizeOfBFH = Marshal.SizeOf(typeof(BITMAPFILEHEADER));
IntPtr ptrBlock = Marshal.AllocCoTaskMem(len + sizeOfBFH);
IntPtr ptrImg = new IntPtr(ptrBlock.ToInt64() + sizeOfBFH);
try
{
// Get the DIB
iBV.GetCurrentImage(ref len, ptrImg);
// Get a copy of the BITMAPINFOHEADER, to be used in the BITMAPFILEHEADER
BITMAPINFOHEADER bmih = (BITMAPINFOHEADER)Marshal.PtrToStructure(
ptrImg, typeof(BITMAPINFOHEADER));
// Create header for a file of type .bmp
BITMAPFILEHEADER bfh = new BITMAPFILEHEADER();
bfh.Type = (UInt16)((((byte)'M') << 8) | ((byte)'B'));
bfh.Size = (uint)(len + sizeOfBFH);
bfh.Reserved1 = 0;
bfh.Reserved2 = 0;
bfh.OffBits = (uint)(sizeOfBFH + bmih.Size);
// Copy the BFH into unmanaged memory, so that we can copy
// everything into a managed byte array all at once
Marshal.StructureToPtr(bfh, ptrBlock, false);
// Pull it out of unmanaged memory into a managed byte[]
byte[] img = new byte[len + sizeOfBFH];
Marshal.Copy(ptrBlock, img, 0, len + sizeOfBFH);
// Save the DIB to a file
System.IO.File.WriteAllBytes("c:\\cxp.bmp", img);
}
finally
{
// Free the unmanaged memory
if (ptrBlock != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(ptrBlock);
}
}
}
