| /* |
| * jdmaster.c |
| * |
| * Copyright (C) 1991-1997, Thomas G. Lane. |
| * Copyright (C) 2009-2010, D. R. Commander. |
| * This file is part of the Independent JPEG Group's software. |
| * For conditions of distribution and use, see the accompanying README file. |
| * |
| * This file contains master control logic for the JPEG decompressor. |
| * These routines are concerned with selecting the modules to be executed |
| * and with determining the number of passes and the work to be done in each |
| * pass. |
| */ |
| |
| #define JPEG_INTERNALS |
| #include "jinclude.h" |
| #include "jpeglib.h" |
| #include "jpegcomp.h" |
| |
| |
| /* Private state */ |
| |
| typedef struct { |
| struct jpeg_decomp_master pub; /* public fields */ |
| |
| int pass_number; /* # of passes completed */ |
| |
| boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */ |
| |
| /* Saved references to initialized quantizer modules, |
| * in case we need to switch modes. |
| */ |
| struct jpeg_color_quantizer * quantizer_1pass; |
| struct jpeg_color_quantizer * quantizer_2pass; |
| } my_decomp_master; |
| |
| typedef my_decomp_master * my_master_ptr; |
| |
| |
| /* |
| * Determine whether merged upsample/color conversion should be used. |
| * CRUCIAL: this must match the actual capabilities of jdmerge.c! |
| */ |
| |
| LOCAL(boolean) |
| use_merged_upsample (j_decompress_ptr cinfo) |
| { |
| #ifdef UPSAMPLE_MERGING_SUPPORTED |
| /* Merging is the equivalent of plain box-filter upsampling */ |
| if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling) |
| return FALSE; |
| /* jdmerge.c only supports YCC=>RGB color conversion */ |
| if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 || |
| (cinfo->out_color_space != JCS_RGB && |
| cinfo->out_color_space != JCS_EXT_RGB && |
| cinfo->out_color_space != JCS_EXT_RGBX && |
| cinfo->out_color_space != JCS_EXT_BGR && |
| cinfo->out_color_space != JCS_EXT_BGRX && |
| cinfo->out_color_space != JCS_EXT_XBGR && |
| cinfo->out_color_space != JCS_EXT_XRGB) || |
| cinfo->out_color_components != rgb_pixelsize[cinfo->out_color_space]) |
| return FALSE; |
| /* and it only handles 2h1v or 2h2v sampling ratios */ |
| if (cinfo->comp_info[0].h_samp_factor != 2 || |
| cinfo->comp_info[1].h_samp_factor != 1 || |
| cinfo->comp_info[2].h_samp_factor != 1 || |
| cinfo->comp_info[0].v_samp_factor > 2 || |
| cinfo->comp_info[1].v_samp_factor != 1 || |
| cinfo->comp_info[2].v_samp_factor != 1) |
| return FALSE; |
| /* furthermore, it doesn't work if we've scaled the IDCTs differently */ |
| if (cinfo->comp_info[0]._DCT_scaled_size != cinfo->_min_DCT_scaled_size || |
| cinfo->comp_info[1]._DCT_scaled_size != cinfo->_min_DCT_scaled_size || |
| cinfo->comp_info[2]._DCT_scaled_size != cinfo->_min_DCT_scaled_size) |
| return FALSE; |
| /* ??? also need to test for upsample-time rescaling, when & if supported */ |
| return TRUE; /* by golly, it'll work... */ |
| #else |
| return FALSE; |
| #endif |
| } |
| |
| |
| /* |
| * Compute output image dimensions and related values. |
| * NOTE: this is exported for possible use by application. |
| * Hence it mustn't do anything that can't be done twice. |
| * Also note that it may be called before the master module is initialized! |
| */ |
| |
| GLOBAL(void) |
| jpeg_calc_output_dimensions (j_decompress_ptr cinfo) |
| /* Do computations that are needed before master selection phase */ |
| { |
| #ifdef IDCT_SCALING_SUPPORTED |
| int ci; |
| jpeg_component_info *compptr; |
| #endif |
| |
| /* Prevent application from calling me at wrong times */ |
| if (cinfo->global_state != DSTATE_READY) |
| ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| |
| #ifdef IDCT_SCALING_SUPPORTED |
| |
| /* Compute actual output image dimensions and DCT scaling choices. */ |
| if (cinfo->scale_num * 8 <= cinfo->scale_denom) { |
| /* Provide 1/8 scaling */ |
| cinfo->output_width = (JDIMENSION) |
| jdiv_round_up((long) cinfo->image_width, 8L); |
| cinfo->output_height = (JDIMENSION) |
| jdiv_round_up((long) cinfo->image_height, 8L); |
| #if JPEG_LIB_VERSION >= 70 |
| cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = 1; |
| #else |
| cinfo->min_DCT_scaled_size = 1; |
| #endif |
| } else if (cinfo->scale_num * 4 <= cinfo->scale_denom) { |
| /* Provide 1/4 scaling */ |
| cinfo->output_width = (JDIMENSION) |
| jdiv_round_up((long) cinfo->image_width, 4L); |
| cinfo->output_height = (JDIMENSION) |
| jdiv_round_up((long) cinfo->image_height, 4L); |
| #if JPEG_LIB_VERSION >= 70 |
| cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = 2; |
| #else |
| cinfo->min_DCT_scaled_size = 2; |
| #endif |
| } else if (cinfo->scale_num * 2 <= cinfo->scale_denom) { |
| /* Provide 1/2 scaling */ |
| cinfo->output_width = (JDIMENSION) |
| jdiv_round_up((long) cinfo->image_width, 2L); |
| cinfo->output_height = (JDIMENSION) |
| jdiv_round_up((long) cinfo->image_height, 2L); |
| #if JPEG_LIB_VERSION >= 70 |
| cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = 4; |
| #else |
| cinfo->min_DCT_scaled_size = 4; |
| #endif |
| } else { |
| /* Provide 1/1 scaling */ |
| cinfo->output_width = cinfo->image_width; |
| cinfo->output_height = cinfo->image_height; |
| #if JPEG_LIB_VERSION >= 70 |
| cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = DCTSIZE; |
| #else |
| cinfo->min_DCT_scaled_size = DCTSIZE; |
| #endif |
| } |
| /* In selecting the actual DCT scaling for each component, we try to |
| * scale up the chroma components via IDCT scaling rather than upsampling. |
| * This saves time if the upsampler gets to use 1:1 scaling. |
| * Note this code assumes that the supported DCT scalings are powers of 2. |
| */ |
| for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
| ci++, compptr++) { |
| int ssize = cinfo->_min_DCT_scaled_size; |
| while (ssize < DCTSIZE && |
| (compptr->h_samp_factor * ssize * 2 <= |
| cinfo->max_h_samp_factor * cinfo->_min_DCT_scaled_size) && |
| (compptr->v_samp_factor * ssize * 2 <= |
| cinfo->max_v_samp_factor * cinfo->_min_DCT_scaled_size)) { |
| ssize = ssize * 2; |
| } |
| #if JPEG_LIB_VERSION >= 70 |
| compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = ssize; |
| #else |
| compptr->DCT_scaled_size = ssize; |
| #endif |
| } |
| |
| /* Recompute downsampled dimensions of components; |
| * application needs to know these if using raw downsampled data. |
| */ |
| for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
| ci++, compptr++) { |
| /* Size in samples, after IDCT scaling */ |
| compptr->downsampled_width = (JDIMENSION) |
| jdiv_round_up((long) cinfo->image_width * |
| (long) (compptr->h_samp_factor * compptr->_DCT_scaled_size), |
| (long) (cinfo->max_h_samp_factor * DCTSIZE)); |
| compptr->downsampled_height = (JDIMENSION) |
| jdiv_round_up((long) cinfo->image_height * |
| (long) (compptr->v_samp_factor * compptr->_DCT_scaled_size), |
| (long) (cinfo->max_v_samp_factor * DCTSIZE)); |
| } |
| |
| #else /* !IDCT_SCALING_SUPPORTED */ |
| |
| /* Hardwire it to "no scaling" */ |
| cinfo->output_width = cinfo->image_width; |
| cinfo->output_height = cinfo->image_height; |
| /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE, |
| * and has computed unscaled downsampled_width and downsampled_height. |
| */ |
| |
| #endif /* IDCT_SCALING_SUPPORTED */ |
| |
| /* Report number of components in selected colorspace. */ |
| /* Probably this should be in the color conversion module... */ |
| switch (cinfo->out_color_space) { |
| case JCS_GRAYSCALE: |
| cinfo->out_color_components = 1; |
| break; |
| case JCS_RGB: |
| case JCS_EXT_RGB: |
| case JCS_EXT_RGBX: |
| case JCS_EXT_BGR: |
| case JCS_EXT_BGRX: |
| case JCS_EXT_XBGR: |
| case JCS_EXT_XRGB: |
| cinfo->out_color_components = rgb_pixelsize[cinfo->out_color_space]; |
| break; |
| case JCS_YCbCr: |
| cinfo->out_color_components = 3; |
| break; |
| case JCS_CMYK: |
| case JCS_YCCK: |
| cinfo->out_color_components = 4; |
| break; |
| default: /* else must be same colorspace as in file */ |
| cinfo->out_color_components = cinfo->num_components; |
| break; |
| } |
| cinfo->output_components = (cinfo->quantize_colors ? 1 : |
| cinfo->out_color_components); |
| |
| /* See if upsampler will want to emit more than one row at a time */ |
| if (use_merged_upsample(cinfo)) |
| cinfo->rec_outbuf_height = cinfo->max_v_samp_factor; |
| else |
| cinfo->rec_outbuf_height = 1; |
| } |
| |
| |
| /* |
| * Several decompression processes need to range-limit values to the range |
| * 0..MAXJSAMPLE; the input value may fall somewhat outside this range |
| * due to noise introduced by quantization, roundoff error, etc. These |
| * processes are inner loops and need to be as fast as possible. On most |
| * machines, particularly CPUs with pipelines or instruction prefetch, |
| * a (subscript-check-less) C table lookup |
| * x = sample_range_limit[x]; |
| * is faster than explicit tests |
| * if (x < 0) x = 0; |
| * else if (x > MAXJSAMPLE) x = MAXJSAMPLE; |
| * These processes all use a common table prepared by the routine below. |
| * |
| * For most steps we can mathematically guarantee that the initial value |
| * of x is within MAXJSAMPLE+1 of the legal range, so a table running from |
| * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial |
| * limiting step (just after the IDCT), a wildly out-of-range value is |
| * possible if the input data is corrupt. To avoid any chance of indexing |
| * off the end of memory and getting a bad-pointer trap, we perform the |
| * post-IDCT limiting thus: |
| * x = range_limit[x & MASK]; |
| * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit |
| * samples. Under normal circumstances this is more than enough range and |
| * a correct output will be generated; with bogus input data the mask will |
| * cause wraparound, and we will safely generate a bogus-but-in-range output. |
| * For the post-IDCT step, we want to convert the data from signed to unsigned |
| * representation by adding CENTERJSAMPLE at the same time that we limit it. |
| * So the post-IDCT limiting table ends up looking like this: |
| * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE, |
| * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times), |
| * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times), |
| * 0,1,...,CENTERJSAMPLE-1 |
| * Negative inputs select values from the upper half of the table after |
| * masking. |
| * |
| * We can save some space by overlapping the start of the post-IDCT table |
| * with the simpler range limiting table. The post-IDCT table begins at |
| * sample_range_limit + CENTERJSAMPLE. |
| * |
| * Note that the table is allocated in near data space on PCs; it's small |
| * enough and used often enough to justify this. |
| */ |
| |
| LOCAL(void) |
| prepare_range_limit_table (j_decompress_ptr cinfo) |
| /* Allocate and fill in the sample_range_limit table */ |
| { |
| JSAMPLE * table; |
| int i; |
| |
| table = (JSAMPLE *) |
| (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE)); |
| table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */ |
| cinfo->sample_range_limit = table; |
| /* First segment of "simple" table: limit[x] = 0 for x < 0 */ |
| MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE)); |
| /* Main part of "simple" table: limit[x] = x */ |
| for (i = 0; i <= MAXJSAMPLE; i++) |
| table[i] = (JSAMPLE) i; |
| table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */ |
| /* End of simple table, rest of first half of post-IDCT table */ |
| for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++) |
| table[i] = MAXJSAMPLE; |
| /* Second half of post-IDCT table */ |
| MEMZERO(table + (2 * (MAXJSAMPLE+1)), |
| (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE)); |
| MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE), |
| cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE)); |
| } |
| |
| |
| /* |
| * Master selection of decompression modules. |
| * This is done once at jpeg_start_decompress time. We determine |
| * which modules will be used and give them appropriate initialization calls. |
| * We also initialize the decompressor input side to begin consuming data. |
| * |
| * Since jpeg_read_header has finished, we know what is in the SOF |
| * and (first) SOS markers. We also have all the application parameter |
| * settings. |
| */ |
| |
| 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) { |
| #ifdef D_ARITH_CODING_SUPPORTED |
| jinit_arith_decoder(cinfo); |
| #else |
| ERREXIT(cinfo, JERR_ARITH_NOTIMPL); |
| #endif |
| } else { |
| if (cinfo->progressive_mode) { |
| #ifdef D_PROGRESSIVE_SUPPORTED |
| jinit_phuff_decoder(cinfo); |
| #else |
| ERREXIT(cinfo, JERR_NOT_COMPILED); |
| #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 */ |
| } |
| |
| |
| /* |
| * Per-pass setup. |
| * This is called at the beginning of each output pass. We determine which |
| * modules will be active during this pass and give them appropriate |
| * start_pass calls. We also set is_dummy_pass to indicate whether this |
| * is a "real" output pass or a dummy pass for color quantization. |
| * (In the latter case, jdapistd.c will crank the pass to completion.) |
| */ |
| |
| METHODDEF(void) |
| prepare_for_output_pass (j_decompress_ptr cinfo) |
| { |
| my_master_ptr master = (my_master_ptr) cinfo->master; |
| |
| if (master->pub.is_dummy_pass) { |
| #ifdef QUANT_2PASS_SUPPORTED |
| /* Final pass of 2-pass quantization */ |
| master->pub.is_dummy_pass = FALSE; |
| (*cinfo->cquantize->start_pass) (cinfo, FALSE); |
| (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST); |
| (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST); |
| #else |
| ERREXIT(cinfo, JERR_NOT_COMPILED); |
| #endif /* QUANT_2PASS_SUPPORTED */ |
| } else { |
| if (cinfo->quantize_colors && cinfo->colormap == NULL) { |
| /* Select new quantization method */ |
| if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) { |
| cinfo->cquantize = master->quantizer_2pass; |
| master->pub.is_dummy_pass = TRUE; |
| } else if (cinfo->enable_1pass_quant) { |
| cinfo->cquantize = master->quantizer_1pass; |
| } else { |
| ERREXIT(cinfo, JERR_MODE_CHANGE); |
| } |
| } |
| (*cinfo->idct->start_pass) (cinfo); |
| (*cinfo->coef->start_output_pass) (cinfo); |
| if (! cinfo->raw_data_out) { |
| if (! master->using_merged_upsample) |
| (*cinfo->cconvert->start_pass) (cinfo); |
| (*cinfo->upsample->start_pass) (cinfo); |
| if (cinfo->quantize_colors) |
| (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass); |
| (*cinfo->post->start_pass) (cinfo, |
| (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU)); |
| (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU); |
| } |
| } |
| |
| /* Set up progress monitor's pass info if present */ |
| if (cinfo->progress != NULL) { |
| cinfo->progress->completed_passes = master->pass_number; |
| cinfo->progress->total_passes = master->pass_number + |
| (master->pub.is_dummy_pass ? 2 : 1); |
| /* In buffered-image mode, we assume one more output pass if EOI not |
| * yet reached, but no more passes if EOI has been reached. |
| */ |
| if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) { |
| cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1); |
| } |
| } |
| } |
| |
| |
| /* |
| * Finish up at end of an output pass. |
| */ |
| |
| METHODDEF(void) |
| finish_output_pass (j_decompress_ptr cinfo) |
| { |
| my_master_ptr master = (my_master_ptr) cinfo->master; |
| |
| if (cinfo->quantize_colors) |
| (*cinfo->cquantize->finish_pass) (cinfo); |
| master->pass_number++; |
| } |
| |
| |
| #ifdef D_MULTISCAN_FILES_SUPPORTED |
| |
| /* |
| * Switch to a new external colormap between output passes. |
| */ |
| |
| GLOBAL(void) |
| jpeg_new_colormap (j_decompress_ptr cinfo) |
| { |
| my_master_ptr master = (my_master_ptr) cinfo->master; |
| |
| /* Prevent application from calling me at wrong times */ |
| if (cinfo->global_state != DSTATE_BUFIMAGE) |
| ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| |
| if (cinfo->quantize_colors && cinfo->enable_external_quant && |
| cinfo->colormap != NULL) { |
| /* Select 2-pass quantizer for external colormap use */ |
| cinfo->cquantize = master->quantizer_2pass; |
| /* Notify quantizer of colormap change */ |
| (*cinfo->cquantize->new_color_map) (cinfo); |
| master->pub.is_dummy_pass = FALSE; /* just in case */ |
| } else |
| ERREXIT(cinfo, JERR_MODE_CHANGE); |
| } |
| |
| #endif /* D_MULTISCAN_FILES_SUPPORTED */ |
| |
| |
| /* |
| * Initialize master decompression control and select active modules. |
| * This is performed at the start of jpeg_start_decompress. |
| */ |
| |
| GLOBAL(void) |
| jinit_master_decompress (j_decompress_ptr cinfo) |
| { |
| my_master_ptr master; |
| |
| master = (my_master_ptr) |
| (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| SIZEOF(my_decomp_master)); |
| cinfo->master = (struct jpeg_decomp_master *) master; |
| master->pub.prepare_for_output_pass = prepare_for_output_pass; |
| master->pub.finish_output_pass = finish_output_pass; |
| |
| master->pub.is_dummy_pass = FALSE; |
| |
| master_selection(cinfo); |
| } |