System.Drawing.FastBitmap.LockBitmap C# (CSharp) Method

        private void LockBitmap()
        {
            if (_locked) throw new InvalidOperationException("Already locked");

            Rectangle bounds = new Rectangle(0, 0, _bitmap.Width, _bitmap.Height);

            // Figure out the number of bytes in a row. This is rounded up to be a multiple
            // of 4 bytes, since a scan line in an image must always be a multiple of 4 bytes
            // in length.
            _width = bounds.Width * sizeof(PixelData);
            if (_width % 4 != 0) _width = 4 * (_width / 4 + 1);

            _bitmapData = _bitmap.LockBits(bounds, ImageLockMode.ReadWrite, PixelFormat.Format32bppRgb);

            _pBase = (byte*)_bitmapData.Scan0.ToPointer();
            _locked = true;
        }