public BitmapRenderer(IntPtr dibHandle)
{
_dibHandle = dibHandle;
_bitmapPointer = Kernel32Native.GlobalLock(dibHandle);
_bitmapInfo = new BitmapInfoHeader();
Marshal.PtrToStructure(_bitmapPointer, _bitmapInfo);
log.Debug(_bitmapInfo.ToString());
_rectangle = new Rectangle();
_rectangle.X = _rectangle.Y = 0;
_rectangle.Width = _bitmapInfo.Width;
_rectangle.Height = _bitmapInfo.Height;
if (_bitmapInfo.SizeImage == 0)
{
_bitmapInfo.SizeImage = ((((_bitmapInfo.Width * _bitmapInfo.BitCount) + 31) & ~31) >> 3) * _bitmapInfo.Height;
}
// The following code only works on x86
Debug.Assert(Marshal.SizeOf(typeof(IntPtr)) == 4);
int pixelInfoPointer = _bitmapInfo.ClrUsed;
if ((pixelInfoPointer == 0) && (_bitmapInfo.BitCount <= 8))
{
pixelInfoPointer = 1 << _bitmapInfo.BitCount;
}
pixelInfoPointer = (pixelInfoPointer * 4) + _bitmapInfo.Size + _bitmapPointer.ToInt32();
_pixelInfoPointer = new IntPtr(pixelInfoPointer);
}