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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 6417 | ashmew2 | 1 | /* |
| 2 | * jdpostct.c |
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| 3 | * |
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| 4 | * Copyright (C) 1994-1996, Thomas G. Lane. |
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| 5 | * This file is part of the Independent JPEG Group's software. |
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| 6 | * For conditions of distribution and use, see the accompanying README file. |
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| 7 | * |
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| 8 | * This file contains the decompression postprocessing controller. |
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| 9 | * This controller manages the upsampling, color conversion, and color |
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| 10 | * quantization/reduction steps; specifically, it controls the buffering |
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| 11 | * between upsample/color conversion and color quantization/reduction. |
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| 12 | * |
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| 13 | * If no color quantization/reduction is required, then this module has no |
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| 14 | * work to do, and it just hands off to the upsample/color conversion code. |
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| 15 | * An integrated upsample/convert/quantize process would replace this module |
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| 16 | * entirely. |
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| 17 | */ |
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| 18 | |||
| 19 | #define JPEG_INTERNALS |
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| 20 | #include "jinclude.h" |
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| 21 | #include "jpeglib.h" |
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| 22 | |||
| 23 | |||
| 24 | /* Private buffer controller object */ |
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| 25 | |||
| 26 | typedef struct { |
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| 27 | struct jpeg_d_post_controller pub; /* public fields */ |
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| 28 | |||
| 29 | /* Color quantization source buffer: this holds output data from |
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| 30 | * the upsample/color conversion step to be passed to the quantizer. |
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| 31 | * For two-pass color quantization, we need a full-image buffer; |
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| 32 | * for one-pass operation, a strip buffer is sufficient. |
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| 33 | */ |
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| 34 | jvirt_sarray_ptr whole_image; /* virtual array, or NULL if one-pass */ |
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| 35 | JSAMPARRAY buffer; /* strip buffer, or current strip of virtual */ |
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| 36 | JDIMENSION strip_height; /* buffer size in rows */ |
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| 37 | /* for two-pass mode only: */ |
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| 38 | JDIMENSION starting_row; /* row # of first row in current strip */ |
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| 39 | JDIMENSION next_row; /* index of next row to fill/empty in strip */ |
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| 40 | } my_post_controller; |
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| 41 | |||
| 42 | typedef my_post_controller * my_post_ptr; |
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| 43 | |||
| 44 | |||
| 45 | /* Forward declarations */ |
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| 46 | METHODDEF(void) post_process_1pass |
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| 47 | JPP((j_decompress_ptr cinfo, |
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| 48 | JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, |
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| 49 | JDIMENSION in_row_groups_avail, |
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| 50 | JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, |
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| 51 | JDIMENSION out_rows_avail)); |
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| 52 | #ifdef QUANT_2PASS_SUPPORTED |
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| 53 | METHODDEF(void) post_process_prepass |
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| 54 | JPP((j_decompress_ptr cinfo, |
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| 55 | JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, |
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| 56 | JDIMENSION in_row_groups_avail, |
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| 57 | JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, |
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| 58 | JDIMENSION out_rows_avail)); |
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| 59 | METHODDEF(void) post_process_2pass |
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| 60 | JPP((j_decompress_ptr cinfo, |
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| 61 | JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, |
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| 62 | JDIMENSION in_row_groups_avail, |
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| 63 | JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, |
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| 64 | JDIMENSION out_rows_avail)); |
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| 65 | #endif |
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| 66 | |||
| 67 | |||
| 68 | /* |
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| 69 | * Initialize for a processing pass. |
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| 70 | */ |
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| 71 | |||
| 72 | METHODDEF(void) |
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| 73 | start_pass_dpost (j_decompress_ptr cinfo, J_BUF_MODE pass_mode) |
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| 74 | { |
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| 75 | my_post_ptr post = (my_post_ptr) cinfo->post; |
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| 76 | |||
| 77 | switch (pass_mode) { |
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| 78 | case JBUF_PASS_THRU: |
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| 79 | if (cinfo->quantize_colors) { |
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| 80 | /* Single-pass processing with color quantization. */ |
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| 81 | post->pub.post_process_data = post_process_1pass; |
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| 82 | /* We could be doing buffered-image output before starting a 2-pass |
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| 83 | * color quantization; in that case, jinit_d_post_controller did not |
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| 84 | * allocate a strip buffer. Use the virtual-array buffer as workspace. |
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| 85 | */ |
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| 86 | if (post->buffer == NULL) { |
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| 87 | post->buffer = (*cinfo->mem->access_virt_sarray) |
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| 88 | ((j_common_ptr) cinfo, post->whole_image, |
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| 89 | (JDIMENSION) 0, post->strip_height, TRUE); |
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| 90 | } |
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| 91 | } else { |
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| 92 | /* For single-pass processing without color quantization, |
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| 93 | * I have no work to do; just call the upsampler directly. |
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| 94 | */ |
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| 95 | post->pub.post_process_data = cinfo->upsample->upsample; |
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| 96 | } |
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| 97 | break; |
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| 98 | #ifdef QUANT_2PASS_SUPPORTED |
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| 99 | case JBUF_SAVE_AND_PASS: |
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| 100 | /* First pass of 2-pass quantization */ |
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| 101 | if (post->whole_image == NULL) |
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| 102 | ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
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| 103 | post->pub.post_process_data = post_process_prepass; |
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| 104 | break; |
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| 105 | case JBUF_CRANK_DEST: |
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| 106 | /* Second pass of 2-pass quantization */ |
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| 107 | if (post->whole_image == NULL) |
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| 108 | ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
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| 109 | post->pub.post_process_data = post_process_2pass; |
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| 110 | break; |
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| 111 | #endif /* QUANT_2PASS_SUPPORTED */ |
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| 112 | default: |
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| 113 | ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
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| 114 | break; |
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| 115 | } |
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| 116 | post->starting_row = post->next_row = 0; |
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| 117 | } |
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| 118 | |||
| 119 | |||
| 120 | /* |
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| 121 | * Process some data in the one-pass (strip buffer) case. |
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| 122 | * This is used for color precision reduction as well as one-pass quantization. |
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| 123 | */ |
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| 124 | |||
| 125 | METHODDEF(void) |
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| 126 | post_process_1pass (j_decompress_ptr cinfo, |
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| 127 | JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, |
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| 128 | JDIMENSION in_row_groups_avail, |
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| 129 | JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, |
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| 130 | JDIMENSION out_rows_avail) |
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| 131 | { |
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| 132 | my_post_ptr post = (my_post_ptr) cinfo->post; |
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| 133 | JDIMENSION num_rows, max_rows; |
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| 134 | |||
| 135 | /* Fill the buffer, but not more than what we can dump out in one go. */ |
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| 136 | /* Note we rely on the upsampler to detect bottom of image. */ |
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| 137 | max_rows = out_rows_avail - *out_row_ctr; |
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| 138 | if (max_rows > post->strip_height) |
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| 139 | max_rows = post->strip_height; |
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| 140 | num_rows = 0; |
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| 141 | (*cinfo->upsample->upsample) (cinfo, |
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| 142 | input_buf, in_row_group_ctr, in_row_groups_avail, |
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| 143 | post->buffer, &num_rows, max_rows); |
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| 144 | /* Quantize and emit data. */ |
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| 145 | (*cinfo->cquantize->color_quantize) (cinfo, |
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| 146 | post->buffer, output_buf + *out_row_ctr, (int) num_rows); |
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| 147 | *out_row_ctr += num_rows; |
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| 148 | } |
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| 149 | |||
| 150 | |||
| 151 | #ifdef QUANT_2PASS_SUPPORTED |
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| 152 | |||
| 153 | /* |
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| 154 | * Process some data in the first pass of 2-pass quantization. |
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| 155 | */ |
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| 156 | |||
| 157 | METHODDEF(void) |
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| 158 | post_process_prepass (j_decompress_ptr cinfo, |
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| 159 | JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, |
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| 160 | JDIMENSION in_row_groups_avail, |
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| 161 | JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, |
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| 162 | JDIMENSION out_rows_avail) |
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| 163 | { |
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| 164 | my_post_ptr post = (my_post_ptr) cinfo->post; |
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| 165 | JDIMENSION old_next_row, num_rows; |
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| 166 | |||
| 167 | /* Reposition virtual buffer if at start of strip. */ |
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| 168 | if (post->next_row == 0) { |
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| 169 | post->buffer = (*cinfo->mem->access_virt_sarray) |
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| 170 | ((j_common_ptr) cinfo, post->whole_image, |
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| 171 | post->starting_row, post->strip_height, TRUE); |
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| 172 | } |
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| 173 | |||
| 174 | /* Upsample some data (up to a strip height's worth). */ |
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| 175 | old_next_row = post->next_row; |
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| 176 | (*cinfo->upsample->upsample) (cinfo, |
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| 177 | input_buf, in_row_group_ctr, in_row_groups_avail, |
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| 178 | post->buffer, &post->next_row, post->strip_height); |
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| 179 | |||
| 180 | /* Allow quantizer to scan new data. No data is emitted, */ |
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| 181 | /* but we advance out_row_ctr so outer loop can tell when we're done. */ |
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| 182 | if (post->next_row > old_next_row) { |
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| 183 | num_rows = post->next_row - old_next_row; |
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| 184 | (*cinfo->cquantize->color_quantize) (cinfo, post->buffer + old_next_row, |
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| 185 | (JSAMPARRAY) NULL, (int) num_rows); |
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| 186 | *out_row_ctr += num_rows; |
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| 187 | } |
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| 188 | |||
| 189 | /* Advance if we filled the strip. */ |
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| 190 | if (post->next_row >= post->strip_height) { |
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| 191 | post->starting_row += post->strip_height; |
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| 192 | post->next_row = 0; |
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| 193 | } |
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| 194 | } |
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| 195 | |||
| 196 | |||
| 197 | /* |
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| 198 | * Process some data in the second pass of 2-pass quantization. |
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| 199 | */ |
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| 200 | |||
| 201 | METHODDEF(void) |
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| 202 | post_process_2pass (j_decompress_ptr cinfo, |
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| 203 | JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, |
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| 204 | JDIMENSION in_row_groups_avail, |
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| 205 | JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, |
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| 206 | JDIMENSION out_rows_avail) |
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| 207 | { |
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| 208 | my_post_ptr post = (my_post_ptr) cinfo->post; |
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| 209 | JDIMENSION num_rows, max_rows; |
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| 210 | |||
| 211 | /* Reposition virtual buffer if at start of strip. */ |
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| 212 | if (post->next_row == 0) { |
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| 213 | post->buffer = (*cinfo->mem->access_virt_sarray) |
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| 214 | ((j_common_ptr) cinfo, post->whole_image, |
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| 215 | post->starting_row, post->strip_height, FALSE); |
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| 216 | } |
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| 217 | |||
| 218 | /* Determine number of rows to emit. */ |
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| 219 | num_rows = post->strip_height - post->next_row; /* available in strip */ |
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| 220 | max_rows = out_rows_avail - *out_row_ctr; /* available in output area */ |
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| 221 | if (num_rows > max_rows) |
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| 222 | num_rows = max_rows; |
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| 223 | /* We have to check bottom of image here, can't depend on upsampler. */ |
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| 224 | max_rows = cinfo->output_height - post->starting_row; |
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| 225 | if (num_rows > max_rows) |
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| 226 | num_rows = max_rows; |
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| 227 | |||
| 228 | /* Quantize and emit data. */ |
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| 229 | (*cinfo->cquantize->color_quantize) (cinfo, |
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| 230 | post->buffer + post->next_row, output_buf + *out_row_ctr, |
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| 231 | (int) num_rows); |
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| 232 | *out_row_ctr += num_rows; |
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| 233 | |||
| 234 | /* Advance if we filled the strip. */ |
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| 235 | post->next_row += num_rows; |
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| 236 | if (post->next_row >= post->strip_height) { |
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| 237 | post->starting_row += post->strip_height; |
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| 238 | post->next_row = 0; |
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| 239 | } |
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| 240 | } |
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| 241 | |||
| 242 | #endif /* QUANT_2PASS_SUPPORTED */ |
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| 243 | |||
| 244 | |||
| 245 | /* |
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| 246 | * Initialize postprocessing controller. |
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| 247 | */ |
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| 248 | |||
| 249 | GLOBAL(void) |
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| 250 | jinit_d_post_controller (j_decompress_ptr cinfo, boolean need_full_buffer) |
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| 251 | { |
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| 252 | my_post_ptr post; |
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| 253 | |||
| 254 | post = (my_post_ptr) |
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| 255 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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| 256 | SIZEOF(my_post_controller)); |
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| 257 | cinfo->post = (struct jpeg_d_post_controller *) post; |
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| 258 | post->pub.start_pass = start_pass_dpost; |
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| 259 | post->whole_image = NULL; /* flag for no virtual arrays */ |
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| 260 | post->buffer = NULL; /* flag for no strip buffer */ |
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| 261 | |||
| 262 | /* Create the quantization buffer, if needed */ |
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| 263 | if (cinfo->quantize_colors) { |
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| 264 | /* The buffer strip height is max_v_samp_factor, which is typically |
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| 265 | * an efficient number of rows for upsampling to return. |
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| 266 | * (In the presence of output rescaling, we might want to be smarter?) |
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| 267 | */ |
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| 268 | post->strip_height = (JDIMENSION) cinfo->max_v_samp_factor; |
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| 269 | if (need_full_buffer) { |
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| 270 | /* Two-pass color quantization: need full-image storage. */ |
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| 271 | /* We round up the number of rows to a multiple of the strip height. */ |
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| 272 | #ifdef QUANT_2PASS_SUPPORTED |
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| 273 | post->whole_image = (*cinfo->mem->request_virt_sarray) |
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| 274 | ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE, |
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| 275 | cinfo->output_width * cinfo->out_color_components, |
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| 276 | (JDIMENSION) jround_up((long) cinfo->output_height, |
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| 277 | (long) post->strip_height), |
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| 278 | post->strip_height); |
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| 279 | #else |
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| 280 | ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
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| 281 | #endif /* QUANT_2PASS_SUPPORTED */ |
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| 282 | } else { |
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| 283 | /* One-pass color quantization: just make a strip buffer. */ |
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| 284 | post->buffer = (*cinfo->mem->alloc_sarray) |
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| 285 | ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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| 286 | cinfo->output_width * cinfo->out_color_components, |
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| 287 | post->strip_height); |
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| 288 | } |
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| 289 | } |
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| 290 | } |