/// <summary>
/// Prepares the encoder part of the codec for a encoding.
/// </summary>
/// <param name="plane">The zero-based sample plane index.</param>
/// <returns>
/// <c>true</c> if this codec successfully prepared its encoder part and ready
/// to encode data; otherwise, <c>false</c>.
/// </returns>
/// <remarks>
/// <b>PreEncode</b> is called after <see cref="SetupEncode"/> and before encoding.
/// </remarks>
public override bool PreEncode(short plane)
{
m_bit = 8;
m_data = 0;
m_encoder = Fax3Encoder.useFax1DEncoder;
/*
* This is necessary for Group 4; otherwise it isn't
* needed because the first scanline of each strip ends
* up being copied into the refline.
*/
if (m_refline != null)
Array.Clear(m_refline, 0, m_refline.Length);
if (is2DEncoding())
{
float res = m_tif.m_dir.td_yresolution;
/*
* The CCITT spec says that when doing 2d encoding, you
* should only do it on K consecutive scanlines, where K
* depends on the resolution of the image being encoded
* (2 for <= 200 lpi, 4 for > 200 lpi). Since the directory
* code initializes td_yresolution to 0, this code will
* select a K of 2 unless the YResolution tag is set
* appropriately. (Note also that we fudge a little here
* and use 150 lpi to avoid problems with units conversion.)
*/
if (m_tif.m_dir.td_resolutionunit == ResolutionUnit.Centimeter)
{
/* convert to inches */
res *= 2.54f;
}
m_maxk = (res > 150 ? 4 : 2);
m_k = m_maxk - 1;
}
else
{
m_maxk = 0;
m_k = 0;
}
m_line = 0;
return true;
}
/// <summary>
/// Encode a buffer of pixels.
/// </summary>
private bool Fax3Encode(byte[] buffer, int offset, int count)
{
m_buffer = buffer;
m_offset = offset;
while (count > 0)
{
if ((m_mode & FaxMode.NoEOL) == 0)
Fax3PutEOL();
if (is2DEncoding())
{
if (m_encoder == Fax3Encoder.useFax1DEncoder)
{
if (!Fax3Encode1DRow())
return false;
m_encoder = Fax3Encoder.useFax2DEncoder;
}
else
{
if (!Fax3Encode2DRow())
return false;
m_k--;
}
if (m_k == 0)
{
m_encoder = Fax3Encoder.useFax1DEncoder;
m_k = m_maxk - 1;
}
else
{
Buffer.BlockCopy(m_buffer, m_offset, m_refline, 0, m_rowbytes);
}
}
else
{
if (!Fax3Encode1DRow())
return false;
}
m_offset += m_rowbytes;
count -= m_rowbytes;
}
return true;
}
private void cleanState()
{
m_mode = FaxMode.CLASSIC;
m_groupoptions = Group3Opt.UNKNOWN;
m_cleanfaxdata = CleanFaxData.CLEAN;
m_badfaxlines = 0;
m_badfaxrun = 0;
m_recvparams = 0;
m_subaddress = null;
m_recvtime = 0;
m_faxdcs = null;
fill = null;
m_rw_mode = 0;
m_rowbytes = 0;
m_rowpixels = 0;
m_decoder = 0;
m_bitmap = null;
m_data = 0;
m_bit = 0;
m_EOLcnt = 0;
m_runs = null;
m_refruns = 0;
m_curruns = 0;
m_a0 = 0;
m_RunLength = 0;
m_thisrun = 0;
m_pa = 0;
m_pb = 0;
m_encoder = 0;
m_encodingFax4 = false;
m_refline = null;
m_k = 0;
m_maxk = 0;
m_line = 0;
m_buffer = null;
m_offset = 0;
}