jpeg_init_read_tile_scanline(j_decompress_ptr cinfo, huffman_index *index,
int *start_x, int *start_y, int *width, int *height)
{
int lines_per_iMCU_row = cinfo->max_v_samp_factor * DCTSIZE;
int lines_per_iMCU_col = cinfo->max_h_samp_factor * DCTSIZE;
int row_offset = *start_y / lines_per_iMCU_row;
int col_left_boundary = ((*start_x / lines_per_iMCU_col)
/ index->MCU_sample_size) * index->MCU_sample_size;
int col_right_boundary =
jdiv_round_up(*start_x + *width, lines_per_iMCU_col);
cinfo->coef->MCU_columns_to_skip =
*start_x / lines_per_iMCU_col - col_left_boundary;
*height = (*start_y - row_offset * lines_per_iMCU_row) + *height;
*start_x = col_left_boundary * lines_per_iMCU_col;
*start_y = row_offset * lines_per_iMCU_row;
cinfo->image_width = jmin(cinfo->original_image_width,
col_right_boundary * lines_per_iMCU_col) -
col_left_boundary * lines_per_iMCU_col;
cinfo->input_iMCU_row = row_offset;
cinfo->output_iMCU_row = row_offset;
jinit_color_deconverter(cinfo);
jpeg_calc_output_dimensions(cinfo);
jinit_upsampler(cinfo);
(*cinfo->master->prepare_for_output_pass) (cinfo);
if (cinfo->progressive_mode)
(*cinfo->entropy->start_pass) (cinfo);
else
jpeg_decompress_per_scan_setup(cinfo);
int sample_size = DCTSIZE / cinfo->min_DCT_scaled_size;
*height = jdiv_round_up(*height, sample_size);
*width = cinfo->output_width;
cinfo->output_scanline = lines_per_iMCU_row * row_offset / sample_size;
cinfo->inputctl->consume_input = cinfo->coef->consume_data;
cinfo->inputctl->consume_input_build_huffman_index =
cinfo->coef->consume_data_build_huffman_index;
cinfo->entropy->index = index;
cinfo->input_iMCU_row = row_offset;
cinfo->output_iMCU_row = row_offset;
cinfo->coef->MCU_column_left_boundary = col_left_boundary;
cinfo->coef->MCU_column_right_boundary = col_right_boundary;
cinfo->coef->column_left_boundary =
col_left_boundary / index->MCU_sample_size;
cinfo->coef->column_right_boundary =
jdiv_round_up(col_right_boundary, index->MCU_sample_size);
}
LOCAL void
master_selection (j_decompress_ptr cinfo)
{
my_master_ptr master = (my_master_ptr) cinfo->master;
boolean use_c_buffer;
long samplesperrow;
JDIMENSION jd_samplesperrow;
/* Initialize dimensions and other stuff */
jpeg_calc_output_dimensions(cinfo);
prepare_range_limit_table(cinfo);
/* Width of an output scanline must be representable as JDIMENSION. */
samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
jd_samplesperrow = (JDIMENSION) samplesperrow;
if ((long) jd_samplesperrow != samplesperrow)
ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
/* Initialize my private state */
master->pass_number = 0;
master->using_merged_upsample = use_merged_upsample(cinfo);
/* Color quantizer selection */
master->quantizer_1pass = NULL;
master->quantizer_2pass = NULL;
/* No mode changes if not using buffered-image mode. */
if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
cinfo->enable_1pass_quant = FALSE;
cinfo->enable_external_quant = FALSE;
cinfo->enable_2pass_quant = FALSE;
}
if (cinfo->quantize_colors) {
if (cinfo->raw_data_out)
ERREXIT(cinfo, JERR_NOTIMPL);
/* 2-pass quantizer only works in 3-component color space. */
if (cinfo->out_color_components != 3) {
cinfo->enable_1pass_quant = TRUE;
cinfo->enable_external_quant = FALSE;
cinfo->enable_2pass_quant = FALSE;
cinfo->colormap = NULL;
} else if (cinfo->colormap != NULL) {
cinfo->enable_external_quant = TRUE;
} else if (cinfo->two_pass_quantize) {
cinfo->enable_2pass_quant = TRUE;
} else {
cinfo->enable_1pass_quant = TRUE;
}
if (cinfo->enable_1pass_quant) {
#ifdef QUANT_1PASS_SUPPORTED
jinit_1pass_quantizer(cinfo);
master->quantizer_1pass = cinfo->cquantize;
#else
ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
}
/* We use the 2-pass code to map to external colormaps. */
if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
#ifdef QUANT_2PASS_SUPPORTED
jinit_2pass_quantizer(cinfo);
master->quantizer_2pass = cinfo->cquantize;
#else
ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
}
/* If both quantizers are initialized, the 2-pass one is left active;
* this is necessary for starting with quantization to an external map.
*/
}
/* Post-processing: in particular, color conversion first */
if (! cinfo->raw_data_out) {
if (master->using_merged_upsample) {
#ifdef UPSAMPLE_MERGING_SUPPORTED
jinit_merged_upsampler(cinfo); /* does color conversion too */
#else
ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
} else {
jinit_color_deconverter(cinfo);
jinit_upsampler(cinfo);
}
jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
}
/* Inverse DCT */
jinit_inverse_dct(cinfo);
/* Entropy decoding: either Huffman or arithmetic coding. */
if (cinfo->arith_code) {
ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
} else {
if (cinfo->progressive_mode) {
#ifdef D_PROGRESSIVE_SUPPORTED
jinit_phuff_decoder(cinfo);
#else
ERREXIT(cinfo, JERR_NO_PROGRESSIVE);
#endif
} else
jinit_huff_decoder(cinfo);
}
/* Initialize principal buffer controllers. */
use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
jinit_d_coef_controller(cinfo, use_c_buffer);
if (! cinfo->raw_data_out)
jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);
/* We can now tell the memory manager to allocate virtual arrays. */
(*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
/* Initialize input side of decompressor to consume first scan. */
(*cinfo->inputctl->start_input_pass) (cinfo);
#ifdef D_MULTISCAN_FILES_SUPPORTED
/* If jpeg_start_decompress will read the whole file, initialize
* progress monitoring appropriately. The input step is counted
* as one pass.
*/
if (cinfo->progress != NULL && ! cinfo->buffered_image &&
cinfo->inputctl->has_multiple_scans) {
int nscans;
/* Estimate number of scans to set pass_limit. */
if (cinfo->progressive_mode) {
/* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
nscans = 2 + 3 * cinfo->num_components;
} else {
/* For a nonprogressive multiscan file, estimate 1 scan per component. */
nscans = cinfo->num_components;
}
cinfo->progress->pass_counter = 0L;
cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
cinfo->progress->completed_passes = 0;
cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
/* Count the input pass as done */
master->pass_number++;
}
#endif /* D_MULTISCAN_FILES_SUPPORTED */
}
