// Initialize for a Huffman-compressed scan using progressive JPEG.
public override void start_pass(bool gather_statistics)
{
m_gather_statistics = gather_statistics;
/* We assume the scan parameters are already validated. */
/* Select execution routines */
bool is_DC_band = (m_cinfo.m_Ss == 0);
if (m_cinfo.m_Ah == 0)
{
if (is_DC_band)
{
m_MCUEncoder = MCUEncoder.mcu_DC_first_encoder;
}
else
{
m_MCUEncoder = MCUEncoder.mcu_AC_first_encoder;
}
}
else
{
if (is_DC_band)
{
m_MCUEncoder = MCUEncoder.mcu_DC_refine_encoder;
}
else
{
m_MCUEncoder = MCUEncoder.mcu_AC_refine_encoder;
/* AC refinement needs a correction bit buffer */
if (m_bit_buffer == null)
{
m_bit_buffer = new char[MAX_CORR_BITS];
}
}
}
/* Only DC coefficients may be interleaved, so m_cinfo.comps_in_scan = 1
* for AC coefficients.
*/
for (int ci = 0; ci < m_cinfo.m_comps_in_scan; ci++)
{
jpeg_component_info componentInfo = m_cinfo.Component_info[m_cinfo.m_cur_comp_info[ci]];
/* Initialize DC predictions to 0 */
m_last_dc_val[ci] = 0;
/* Get table index */
int tbl;
if (is_DC_band)
{
if (m_cinfo.m_Ah != 0) /* DC refinement needs no table */
{
continue;
}
tbl = componentInfo.Dc_tbl_no;
}
else
{
m_ac_tbl_no = componentInfo.Ac_tbl_no;
tbl = componentInfo.Ac_tbl_no;
}
if (m_gather_statistics)
{
/* Check for invalid table index */
/* (make_c_derived_tbl does this in the other path) */
if (tbl < 0 || tbl >= JpegConstants.NUM_HUFF_TBLS)
{
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_NO_HUFF_TABLE, tbl);
}
/* Allocate and zero the statistics tables */
/* Note that jpeg_gen_optimal_table expects 257 entries in each table! */
if (m_count_ptrs[tbl] == null)
{
m_count_ptrs[tbl] = new long[257];
}
Array.Clear(m_count_ptrs[tbl], 0, 257);
}
else
{
/* Compute derived values for Huffman table */
/* We may do this more than once for a table, but it's not expensive */
jpeg_make_c_derived_tbl(is_DC_band, tbl, ref m_derived_tbls[tbl]);
}
}
/* Initialize AC stuff */
m_EOBRUN = 0;
m_BE = 0;
/* Initialize bit buffer to empty */
m_put_buffer = 0;
m_put_bits = 0;
/* Initialize restart stuff */
m_restarts_to_go = m_cinfo.m_restart_interval;
m_next_restart_num = 0;
}
// Initialize for a Huffman-compressed scan using progressive JPEG.
public override void start_pass(bool gather_statistics)
{
m_gather_statistics = gather_statistics;
/* We assume the scan parameters are already validated. */
/* Select execution routines */
bool is_DC_band = (m_cinfo.m_Ss == 0);
if (m_cinfo.m_Ah == 0)
{
if (is_DC_band)
m_MCUEncoder = MCUEncoder.mcu_DC_first_encoder;
else
m_MCUEncoder = MCUEncoder.mcu_AC_first_encoder;
}
else
{
if (is_DC_band)
{
m_MCUEncoder = MCUEncoder.mcu_DC_refine_encoder;
}
else
{
m_MCUEncoder = MCUEncoder.mcu_AC_refine_encoder;
/* AC refinement needs a correction bit buffer */
if (m_bit_buffer == null)
m_bit_buffer = new char[MAX_CORR_BITS];
}
}
/* Only DC coefficients may be interleaved, so m_cinfo.comps_in_scan = 1
* for AC coefficients.
*/
for (int ci = 0; ci < m_cinfo.m_comps_in_scan; ci++)
{
jpeg_component_info componentInfo = m_cinfo.Component_info[m_cinfo.m_cur_comp_info[ci]];
/* Initialize DC predictions to 0 */
m_last_dc_val[ci] = 0;
/* Get table index */
int tbl;
if (is_DC_band)
{
if (m_cinfo.m_Ah != 0) /* DC refinement needs no table */
continue;
tbl = componentInfo.Dc_tbl_no;
}
else
{
m_ac_tbl_no = componentInfo.Ac_tbl_no;
tbl = componentInfo.Ac_tbl_no;
}
if (m_gather_statistics)
{
/* Check for invalid table index */
/* (make_c_derived_tbl does this in the other path) */
if (tbl < 0 || tbl >= JpegConstants.NUM_HUFF_TBLS)
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_NO_HUFF_TABLE, tbl);
/* Allocate and zero the statistics tables */
/* Note that jpeg_gen_optimal_table expects 257 entries in each table! */
if (m_count_ptrs[tbl] == null)
m_count_ptrs[tbl] = new long[257];
Array.Clear(m_count_ptrs[tbl], 0, 257);
}
else
{
/* Compute derived values for Huffman table */
/* We may do this more than once for a table, but it's not expensive */
jpeg_make_c_derived_tbl(is_DC_band, tbl, ref m_derived_tbls[tbl]);
}
}
/* Initialize AC stuff */
m_EOBRUN = 0;
m_BE = 0;
/* Initialize bit buffer to empty */
m_put_buffer = 0;
m_put_bits = 0;
/* Initialize restart stuff */
m_restarts_to_go = m_cinfo.m_restart_interval;
m_next_restart_num = 0;
}
