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Dependencies:   uzair Camera_LS_Y201 F7_Ethernet LCD_DISCO_F746NG NetworkAPI SDFileSystem mbed

includes/jdsample.c@0:791a779d6220, 2017-07-31 (annotated)

Committer:
shoaib_ahmed
Date:
Mon Jul 31 09:16:35 2017 +0000
Revision:
0:791a779d6220
final project;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
shoaib_ahmed 0:791a779d6220 1 /*
shoaib_ahmed 0:791a779d6220 2 * jdsample.c
shoaib_ahmed 0:791a779d6220 3 *
shoaib_ahmed 0:791a779d6220 4 * Copyright (C) 1991-1996, Thomas G. Lane.
shoaib_ahmed 0:791a779d6220 5 * Modified 2002-2015 by Guido Vollbeding.
shoaib_ahmed 0:791a779d6220 6 * This file is part of the Independent JPEG Group's software.
shoaib_ahmed 0:791a779d6220 7 * For conditions of distribution and use, see the accompanying README file.
shoaib_ahmed 0:791a779d6220 8 *
shoaib_ahmed 0:791a779d6220 9 * This file contains upsampling routines.
shoaib_ahmed 0:791a779d6220 10 *
shoaib_ahmed 0:791a779d6220 11 * Upsampling input data is counted in "row groups". A row group
shoaib_ahmed 0:791a779d6220 12 * is defined to be (v_samp_factor * DCT_v_scaled_size / min_DCT_v_scaled_size)
shoaib_ahmed 0:791a779d6220 13 * sample rows of each component. Upsampling will normally produce
shoaib_ahmed 0:791a779d6220 14 * max_v_samp_factor pixel rows from each row group (but this could vary
shoaib_ahmed 0:791a779d6220 15 * if the upsampler is applying a scale factor of its own).
shoaib_ahmed 0:791a779d6220 16 *
shoaib_ahmed 0:791a779d6220 17 * An excellent reference for image resampling is
shoaib_ahmed 0:791a779d6220 18 * Digital Image Warping, George Wolberg, 1990.
shoaib_ahmed 0:791a779d6220 19 * Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.
shoaib_ahmed 0:791a779d6220 20 */
shoaib_ahmed 0:791a779d6220 21
shoaib_ahmed 0:791a779d6220 22 #define JPEG_INTERNALS
shoaib_ahmed 0:791a779d6220 23 #include "jinclude.h"
shoaib_ahmed 0:791a779d6220 24 #include "jpeglib.h"
shoaib_ahmed 0:791a779d6220 25
shoaib_ahmed 0:791a779d6220 26
shoaib_ahmed 0:791a779d6220 27 /* Pointer to routine to upsample a single component */
shoaib_ahmed 0:791a779d6220 28 typedef JMETHOD(void, upsample1_ptr,
shoaib_ahmed 0:791a779d6220 29 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
shoaib_ahmed 0:791a779d6220 30 JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr));
shoaib_ahmed 0:791a779d6220 31
shoaib_ahmed 0:791a779d6220 32 /* Private subobject */
shoaib_ahmed 0:791a779d6220 33
shoaib_ahmed 0:791a779d6220 34 typedef struct {
shoaib_ahmed 0:791a779d6220 35 struct jpeg_upsampler pub; /* public fields */
shoaib_ahmed 0:791a779d6220 36
shoaib_ahmed 0:791a779d6220 37 /* Color conversion buffer. When using separate upsampling and color
shoaib_ahmed 0:791a779d6220 38 * conversion steps, this buffer holds one upsampled row group until it
shoaib_ahmed 0:791a779d6220 39 * has been color converted and output.
shoaib_ahmed 0:791a779d6220 40 * Note: we do not allocate any storage for component(s) which are full-size,
shoaib_ahmed 0:791a779d6220 41 * ie do not need rescaling. The corresponding entry of color_buf[] is
shoaib_ahmed 0:791a779d6220 42 * simply set to point to the input data array, thereby avoiding copying.
shoaib_ahmed 0:791a779d6220 43 */
shoaib_ahmed 0:791a779d6220 44 JSAMPARRAY color_buf[MAX_COMPONENTS];
shoaib_ahmed 0:791a779d6220 45
shoaib_ahmed 0:791a779d6220 46 /* Per-component upsampling method pointers */
shoaib_ahmed 0:791a779d6220 47 upsample1_ptr methods[MAX_COMPONENTS];
shoaib_ahmed 0:791a779d6220 48
shoaib_ahmed 0:791a779d6220 49 int next_row_out; /* counts rows emitted from color_buf */
shoaib_ahmed 0:791a779d6220 50 JDIMENSION rows_to_go; /* counts rows remaining in image */
shoaib_ahmed 0:791a779d6220 51
shoaib_ahmed 0:791a779d6220 52 /* Height of an input row group for each component. */
shoaib_ahmed 0:791a779d6220 53 int rowgroup_height[MAX_COMPONENTS];
shoaib_ahmed 0:791a779d6220 54
shoaib_ahmed 0:791a779d6220 55 /* These arrays save pixel expansion factors so that int_expand need not
shoaib_ahmed 0:791a779d6220 56 * recompute them each time. They are unused for other upsampling methods.
shoaib_ahmed 0:791a779d6220 57 */
shoaib_ahmed 0:791a779d6220 58 UINT8 h_expand[MAX_COMPONENTS];
shoaib_ahmed 0:791a779d6220 59 UINT8 v_expand[MAX_COMPONENTS];
shoaib_ahmed 0:791a779d6220 60 } my_upsampler;
shoaib_ahmed 0:791a779d6220 61
shoaib_ahmed 0:791a779d6220 62 typedef my_upsampler * my_upsample_ptr;
shoaib_ahmed 0:791a779d6220 63
shoaib_ahmed 0:791a779d6220 64
shoaib_ahmed 0:791a779d6220 65 /*
shoaib_ahmed 0:791a779d6220 66 * Initialize for an upsampling pass.
shoaib_ahmed 0:791a779d6220 67 */
shoaib_ahmed 0:791a779d6220 68
shoaib_ahmed 0:791a779d6220 69 METHODDEF(void)
shoaib_ahmed 0:791a779d6220 70 start_pass_upsample (j_decompress_ptr cinfo)
shoaib_ahmed 0:791a779d6220 71 {
shoaib_ahmed 0:791a779d6220 72 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
shoaib_ahmed 0:791a779d6220 73
shoaib_ahmed 0:791a779d6220 74 /* Mark the conversion buffer empty */
shoaib_ahmed 0:791a779d6220 75 upsample->next_row_out = cinfo->max_v_samp_factor;
shoaib_ahmed 0:791a779d6220 76 /* Initialize total-height counter for detecting bottom of image */
shoaib_ahmed 0:791a779d6220 77 upsample->rows_to_go = cinfo->output_height;
shoaib_ahmed 0:791a779d6220 78 }
shoaib_ahmed 0:791a779d6220 79
shoaib_ahmed 0:791a779d6220 80
shoaib_ahmed 0:791a779d6220 81 /*
shoaib_ahmed 0:791a779d6220 82 * Control routine to do upsampling (and color conversion).
shoaib_ahmed 0:791a779d6220 83 *
shoaib_ahmed 0:791a779d6220 84 * In this version we upsample each component independently.
shoaib_ahmed 0:791a779d6220 85 * We upsample one row group into the conversion buffer, then apply
shoaib_ahmed 0:791a779d6220 86 * color conversion a row at a time.
shoaib_ahmed 0:791a779d6220 87 */
shoaib_ahmed 0:791a779d6220 88
shoaib_ahmed 0:791a779d6220 89 METHODDEF(void)
shoaib_ahmed 0:791a779d6220 90 sep_upsample (j_decompress_ptr cinfo,
shoaib_ahmed 0:791a779d6220 91 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
shoaib_ahmed 0:791a779d6220 92 JDIMENSION in_row_groups_avail,
shoaib_ahmed 0:791a779d6220 93 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
shoaib_ahmed 0:791a779d6220 94 JDIMENSION out_rows_avail)
shoaib_ahmed 0:791a779d6220 95 {
shoaib_ahmed 0:791a779d6220 96 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
shoaib_ahmed 0:791a779d6220 97 int ci;
shoaib_ahmed 0:791a779d6220 98 jpeg_component_info * compptr;
shoaib_ahmed 0:791a779d6220 99 JDIMENSION num_rows;
shoaib_ahmed 0:791a779d6220 100
shoaib_ahmed 0:791a779d6220 101 /* Fill the conversion buffer, if it's empty */
shoaib_ahmed 0:791a779d6220 102 if (upsample->next_row_out >= cinfo->max_v_samp_factor) {
shoaib_ahmed 0:791a779d6220 103 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
shoaib_ahmed 0:791a779d6220 104 ci++, compptr++) {
shoaib_ahmed 0:791a779d6220 105 /* Invoke per-component upsample method. Notice we pass a POINTER
shoaib_ahmed 0:791a779d6220 106 * to color_buf[ci], so that fullsize_upsample can change it.
shoaib_ahmed 0:791a779d6220 107 */
shoaib_ahmed 0:791a779d6220 108 (*upsample->methods[ci]) (cinfo, compptr,
shoaib_ahmed 0:791a779d6220 109 input_buf[ci] + (*in_row_group_ctr * upsample->rowgroup_height[ci]),
shoaib_ahmed 0:791a779d6220 110 upsample->color_buf + ci);
shoaib_ahmed 0:791a779d6220 111 }
shoaib_ahmed 0:791a779d6220 112 upsample->next_row_out = 0;
shoaib_ahmed 0:791a779d6220 113 }
shoaib_ahmed 0:791a779d6220 114
shoaib_ahmed 0:791a779d6220 115 /* Color-convert and emit rows */
shoaib_ahmed 0:791a779d6220 116
shoaib_ahmed 0:791a779d6220 117 /* How many we have in the buffer: */
shoaib_ahmed 0:791a779d6220 118 num_rows = (JDIMENSION) (cinfo->max_v_samp_factor - upsample->next_row_out);
shoaib_ahmed 0:791a779d6220 119 /* Not more than the distance to the end of the image. Need this test
shoaib_ahmed 0:791a779d6220 120 * in case the image height is not a multiple of max_v_samp_factor:
shoaib_ahmed 0:791a779d6220 121 */
shoaib_ahmed 0:791a779d6220 122 if (num_rows > upsample->rows_to_go)
shoaib_ahmed 0:791a779d6220 123 num_rows = upsample->rows_to_go;
shoaib_ahmed 0:791a779d6220 124 /* And not more than what the client can accept: */
shoaib_ahmed 0:791a779d6220 125 out_rows_avail -= *out_row_ctr;
shoaib_ahmed 0:791a779d6220 126 if (num_rows > out_rows_avail)
shoaib_ahmed 0:791a779d6220 127 num_rows = out_rows_avail;
shoaib_ahmed 0:791a779d6220 128
shoaib_ahmed 0:791a779d6220 129 (*cinfo->cconvert->color_convert) (cinfo, upsample->color_buf,
shoaib_ahmed 0:791a779d6220 130 (JDIMENSION) upsample->next_row_out,
shoaib_ahmed 0:791a779d6220 131 output_buf + *out_row_ctr,
shoaib_ahmed 0:791a779d6220 132 (int) num_rows);
shoaib_ahmed 0:791a779d6220 133
shoaib_ahmed 0:791a779d6220 134 /* Adjust counts */
shoaib_ahmed 0:791a779d6220 135 *out_row_ctr += num_rows;
shoaib_ahmed 0:791a779d6220 136 upsample->rows_to_go -= num_rows;
shoaib_ahmed 0:791a779d6220 137 upsample->next_row_out += num_rows;
shoaib_ahmed 0:791a779d6220 138 /* When the buffer is emptied, declare this input row group consumed */
shoaib_ahmed 0:791a779d6220 139 if (upsample->next_row_out >= cinfo->max_v_samp_factor)
shoaib_ahmed 0:791a779d6220 140 (*in_row_group_ctr)++;
shoaib_ahmed 0:791a779d6220 141 }
shoaib_ahmed 0:791a779d6220 142
shoaib_ahmed 0:791a779d6220 143
shoaib_ahmed 0:791a779d6220 144 /*
shoaib_ahmed 0:791a779d6220 145 * These are the routines invoked by sep_upsample to upsample pixel values
shoaib_ahmed 0:791a779d6220 146 * of a single component. One row group is processed per call.
shoaib_ahmed 0:791a779d6220 147 */
shoaib_ahmed 0:791a779d6220 148
shoaib_ahmed 0:791a779d6220 149
shoaib_ahmed 0:791a779d6220 150 /*
shoaib_ahmed 0:791a779d6220 151 * For full-size components, we just make color_buf[ci] point at the
shoaib_ahmed 0:791a779d6220 152 * input buffer, and thus avoid copying any data. Note that this is
shoaib_ahmed 0:791a779d6220 153 * safe only because sep_upsample doesn't declare the input row group
shoaib_ahmed 0:791a779d6220 154 * "consumed" until we are done color converting and emitting it.
shoaib_ahmed 0:791a779d6220 155 */
shoaib_ahmed 0:791a779d6220 156
shoaib_ahmed 0:791a779d6220 157 METHODDEF(void)
shoaib_ahmed 0:791a779d6220 158 fullsize_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
shoaib_ahmed 0:791a779d6220 159 JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
shoaib_ahmed 0:791a779d6220 160 {
shoaib_ahmed 0:791a779d6220 161 *output_data_ptr = input_data;
shoaib_ahmed 0:791a779d6220 162 }
shoaib_ahmed 0:791a779d6220 163
shoaib_ahmed 0:791a779d6220 164
shoaib_ahmed 0:791a779d6220 165 /*
shoaib_ahmed 0:791a779d6220 166 * This is a no-op version used for "uninteresting" components.
shoaib_ahmed 0:791a779d6220 167 * These components will not be referenced by color conversion.
shoaib_ahmed 0:791a779d6220 168 */
shoaib_ahmed 0:791a779d6220 169
shoaib_ahmed 0:791a779d6220 170 METHODDEF(void)
shoaib_ahmed 0:791a779d6220 171 noop_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
shoaib_ahmed 0:791a779d6220 172 JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
shoaib_ahmed 0:791a779d6220 173 {
shoaib_ahmed 0:791a779d6220 174 *output_data_ptr = NULL; /* safety check */
shoaib_ahmed 0:791a779d6220 175 }
shoaib_ahmed 0:791a779d6220 176
shoaib_ahmed 0:791a779d6220 177
shoaib_ahmed 0:791a779d6220 178 /*
shoaib_ahmed 0:791a779d6220 179 * This version handles any integral sampling ratios.
shoaib_ahmed 0:791a779d6220 180 * This is not used for typical JPEG files, so it need not be fast.
shoaib_ahmed 0:791a779d6220 181 * Nor, for that matter, is it particularly accurate: the algorithm is
shoaib_ahmed 0:791a779d6220 182 * simple replication of the input pixel onto the corresponding output
shoaib_ahmed 0:791a779d6220 183 * pixels. The hi-falutin sampling literature refers to this as a
shoaib_ahmed 0:791a779d6220 184 * "box filter". A box filter tends to introduce visible artifacts,
shoaib_ahmed 0:791a779d6220 185 * so if you are actually going to use 3:1 or 4:1 sampling ratios
shoaib_ahmed 0:791a779d6220 186 * you would be well advised to improve this code.
shoaib_ahmed 0:791a779d6220 187 */
shoaib_ahmed 0:791a779d6220 188
shoaib_ahmed 0:791a779d6220 189 METHODDEF(void)
shoaib_ahmed 0:791a779d6220 190 int_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
shoaib_ahmed 0:791a779d6220 191 JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
shoaib_ahmed 0:791a779d6220 192 {
shoaib_ahmed 0:791a779d6220 193 my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
shoaib_ahmed 0:791a779d6220 194 JSAMPARRAY output_data = *output_data_ptr;
shoaib_ahmed 0:791a779d6220 195 register JSAMPROW inptr, outptr;
shoaib_ahmed 0:791a779d6220 196 register JSAMPLE invalue;
shoaib_ahmed 0:791a779d6220 197 register int h;
shoaib_ahmed 0:791a779d6220 198 JSAMPROW outend;
shoaib_ahmed 0:791a779d6220 199 int h_expand, v_expand;
shoaib_ahmed 0:791a779d6220 200 int inrow, outrow;
shoaib_ahmed 0:791a779d6220 201
shoaib_ahmed 0:791a779d6220 202 h_expand = upsample->h_expand[compptr->component_index];
shoaib_ahmed 0:791a779d6220 203 v_expand = upsample->v_expand[compptr->component_index];
shoaib_ahmed 0:791a779d6220 204
shoaib_ahmed 0:791a779d6220 205 inrow = outrow = 0;
shoaib_ahmed 0:791a779d6220 206 while (outrow < cinfo->max_v_samp_factor) {
shoaib_ahmed 0:791a779d6220 207 /* Generate one output row with proper horizontal expansion */
shoaib_ahmed 0:791a779d6220 208 inptr = input_data[inrow];
shoaib_ahmed 0:791a779d6220 209 outptr = output_data[outrow];
shoaib_ahmed 0:791a779d6220 210 outend = outptr + cinfo->output_width;
shoaib_ahmed 0:791a779d6220 211 while (outptr < outend) {
shoaib_ahmed 0:791a779d6220 212 invalue = *inptr++; /* don't need GETJSAMPLE() here */
shoaib_ahmed 0:791a779d6220 213 for (h = h_expand; h > 0; h--) {
shoaib_ahmed 0:791a779d6220 214 *outptr++ = invalue;
shoaib_ahmed 0:791a779d6220 215 }
shoaib_ahmed 0:791a779d6220 216 }
shoaib_ahmed 0:791a779d6220 217 /* Generate any additional output rows by duplicating the first one */
shoaib_ahmed 0:791a779d6220 218 if (v_expand > 1) {
shoaib_ahmed 0:791a779d6220 219 jcopy_sample_rows(output_data, outrow, output_data, outrow+1,
shoaib_ahmed 0:791a779d6220 220 v_expand-1, cinfo->output_width);
shoaib_ahmed 0:791a779d6220 221 }
shoaib_ahmed 0:791a779d6220 222 inrow++;
shoaib_ahmed 0:791a779d6220 223 outrow += v_expand;
shoaib_ahmed 0:791a779d6220 224 }
shoaib_ahmed 0:791a779d6220 225 }
shoaib_ahmed 0:791a779d6220 226
shoaib_ahmed 0:791a779d6220 227
shoaib_ahmed 0:791a779d6220 228 /*
shoaib_ahmed 0:791a779d6220 229 * Fast processing for the common case of 2:1 horizontal and 1:1 vertical.
shoaib_ahmed 0:791a779d6220 230 * It's still a box filter.
shoaib_ahmed 0:791a779d6220 231 */
shoaib_ahmed 0:791a779d6220 232
shoaib_ahmed 0:791a779d6220 233 METHODDEF(void)
shoaib_ahmed 0:791a779d6220 234 h2v1_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
shoaib_ahmed 0:791a779d6220 235 JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
shoaib_ahmed 0:791a779d6220 236 {
shoaib_ahmed 0:791a779d6220 237 JSAMPARRAY output_data = *output_data_ptr;
shoaib_ahmed 0:791a779d6220 238 register JSAMPROW inptr, outptr;
shoaib_ahmed 0:791a779d6220 239 register JSAMPLE invalue;
shoaib_ahmed 0:791a779d6220 240 JSAMPROW outend;
shoaib_ahmed 0:791a779d6220 241 int outrow;
shoaib_ahmed 0:791a779d6220 242
shoaib_ahmed 0:791a779d6220 243 for (outrow = 0; outrow < cinfo->max_v_samp_factor; outrow++) {
shoaib_ahmed 0:791a779d6220 244 inptr = input_data[outrow];
shoaib_ahmed 0:791a779d6220 245 outptr = output_data[outrow];
shoaib_ahmed 0:791a779d6220 246 outend = outptr + cinfo->output_width;
shoaib_ahmed 0:791a779d6220 247 while (outptr < outend) {
shoaib_ahmed 0:791a779d6220 248 invalue = *inptr++; /* don't need GETJSAMPLE() here */
shoaib_ahmed 0:791a779d6220 249 *outptr++ = invalue;
shoaib_ahmed 0:791a779d6220 250 *outptr++ = invalue;
shoaib_ahmed 0:791a779d6220 251 }
shoaib_ahmed 0:791a779d6220 252 }
shoaib_ahmed 0:791a779d6220 253 }
shoaib_ahmed 0:791a779d6220 254
shoaib_ahmed 0:791a779d6220 255
shoaib_ahmed 0:791a779d6220 256 /*
shoaib_ahmed 0:791a779d6220 257 * Fast processing for the common case of 2:1 horizontal and 2:1 vertical.
shoaib_ahmed 0:791a779d6220 258 * It's still a box filter.
shoaib_ahmed 0:791a779d6220 259 */
shoaib_ahmed 0:791a779d6220 260
shoaib_ahmed 0:791a779d6220 261 METHODDEF(void)
shoaib_ahmed 0:791a779d6220 262 h2v2_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
shoaib_ahmed 0:791a779d6220 263 JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
shoaib_ahmed 0:791a779d6220 264 {
shoaib_ahmed 0:791a779d6220 265 JSAMPARRAY output_data = *output_data_ptr;
shoaib_ahmed 0:791a779d6220 266 register JSAMPROW inptr, outptr;
shoaib_ahmed 0:791a779d6220 267 register JSAMPLE invalue;
shoaib_ahmed 0:791a779d6220 268 JSAMPROW outend;
shoaib_ahmed 0:791a779d6220 269 int inrow, outrow;
shoaib_ahmed 0:791a779d6220 270
shoaib_ahmed 0:791a779d6220 271 inrow = outrow = 0;
shoaib_ahmed 0:791a779d6220 272 while (outrow < cinfo->max_v_samp_factor) {
shoaib_ahmed 0:791a779d6220 273 inptr = input_data[inrow];
shoaib_ahmed 0:791a779d6220 274 outptr = output_data[outrow];
shoaib_ahmed 0:791a779d6220 275 outend = outptr + cinfo->output_width;
shoaib_ahmed 0:791a779d6220 276 while (outptr < outend) {
shoaib_ahmed 0:791a779d6220 277 invalue = *inptr++; /* don't need GETJSAMPLE() here */
shoaib_ahmed 0:791a779d6220 278 *outptr++ = invalue;
shoaib_ahmed 0:791a779d6220 279 *outptr++ = invalue;
shoaib_ahmed 0:791a779d6220 280 }
shoaib_ahmed 0:791a779d6220 281 jcopy_sample_rows(output_data, outrow, output_data, outrow+1,
shoaib_ahmed 0:791a779d6220 282 1, cinfo->output_width);
shoaib_ahmed 0:791a779d6220 283 inrow++;
shoaib_ahmed 0:791a779d6220 284 outrow += 2;
shoaib_ahmed 0:791a779d6220 285 }
shoaib_ahmed 0:791a779d6220 286 }
shoaib_ahmed 0:791a779d6220 287
shoaib_ahmed 0:791a779d6220 288
shoaib_ahmed 0:791a779d6220 289 /*
shoaib_ahmed 0:791a779d6220 290 * Module initialization routine for upsampling.
shoaib_ahmed 0:791a779d6220 291 */
shoaib_ahmed 0:791a779d6220 292
shoaib_ahmed 0:791a779d6220 293 GLOBAL(void)
shoaib_ahmed 0:791a779d6220 294 jinit_upsampler (j_decompress_ptr cinfo)
shoaib_ahmed 0:791a779d6220 295 {
shoaib_ahmed 0:791a779d6220 296 my_upsample_ptr upsample;
shoaib_ahmed 0:791a779d6220 297 int ci;
shoaib_ahmed 0:791a779d6220 298 jpeg_component_info * compptr;
shoaib_ahmed 0:791a779d6220 299 int h_in_group, v_in_group, h_out_group, v_out_group;
shoaib_ahmed 0:791a779d6220 300
shoaib_ahmed 0:791a779d6220 301 upsample = (my_upsample_ptr)
shoaib_ahmed 0:791a779d6220 302 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
shoaib_ahmed 0:791a779d6220 303 SIZEOF(my_upsampler));
shoaib_ahmed 0:791a779d6220 304 cinfo->upsample = &upsample->pub;
shoaib_ahmed 0:791a779d6220 305 upsample->pub.start_pass = start_pass_upsample;
shoaib_ahmed 0:791a779d6220 306 upsample->pub.upsample = sep_upsample;
shoaib_ahmed 0:791a779d6220 307 upsample->pub.need_context_rows = FALSE; /* until we find out differently */
shoaib_ahmed 0:791a779d6220 308
shoaib_ahmed 0:791a779d6220 309 if (cinfo->CCIR601_sampling) /* this isn't supported */
shoaib_ahmed 0:791a779d6220 310 ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);
shoaib_ahmed 0:791a779d6220 311
shoaib_ahmed 0:791a779d6220 312 /* Verify we can handle the sampling factors, select per-component methods,
shoaib_ahmed 0:791a779d6220 313 * and create storage as needed.
shoaib_ahmed 0:791a779d6220 314 */
shoaib_ahmed 0:791a779d6220 315 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
shoaib_ahmed 0:791a779d6220 316 ci++, compptr++) {
shoaib_ahmed 0:791a779d6220 317 /* Compute size of an "input group" after IDCT scaling. This many samples
shoaib_ahmed 0:791a779d6220 318 * are to be converted to max_h_samp_factor * max_v_samp_factor pixels.
shoaib_ahmed 0:791a779d6220 319 */
shoaib_ahmed 0:791a779d6220 320 h_in_group = (compptr->h_samp_factor * compptr->DCT_h_scaled_size) /
shoaib_ahmed 0:791a779d6220 321 cinfo->min_DCT_h_scaled_size;
shoaib_ahmed 0:791a779d6220 322 v_in_group = (compptr->v_samp_factor * compptr->DCT_v_scaled_size) /
shoaib_ahmed 0:791a779d6220 323 cinfo->min_DCT_v_scaled_size;
shoaib_ahmed 0:791a779d6220 324 h_out_group = cinfo->max_h_samp_factor;
shoaib_ahmed 0:791a779d6220 325 v_out_group = cinfo->max_v_samp_factor;
shoaib_ahmed 0:791a779d6220 326 upsample->rowgroup_height[ci] = v_in_group; /* save for use later */
shoaib_ahmed 0:791a779d6220 327 if (! compptr->component_needed) {
shoaib_ahmed 0:791a779d6220 328 /* Don't bother to upsample an uninteresting component. */
shoaib_ahmed 0:791a779d6220 329 upsample->methods[ci] = noop_upsample;
shoaib_ahmed 0:791a779d6220 330 continue; /* don't need to allocate buffer */
shoaib_ahmed 0:791a779d6220 331 }
shoaib_ahmed 0:791a779d6220 332 if (h_in_group == h_out_group && v_in_group == v_out_group) {
shoaib_ahmed 0:791a779d6220 333 /* Fullsize components can be processed without any work. */
shoaib_ahmed 0:791a779d6220 334 upsample->methods[ci] = fullsize_upsample;
shoaib_ahmed 0:791a779d6220 335 continue; /* don't need to allocate buffer */
shoaib_ahmed 0:791a779d6220 336 }
shoaib_ahmed 0:791a779d6220 337 if (h_in_group * 2 == h_out_group && v_in_group == v_out_group) {
shoaib_ahmed 0:791a779d6220 338 /* Special case for 2h1v upsampling */
shoaib_ahmed 0:791a779d6220 339 upsample->methods[ci] = h2v1_upsample;
shoaib_ahmed 0:791a779d6220 340 } else if (h_in_group * 2 == h_out_group &&
shoaib_ahmed 0:791a779d6220 341 v_in_group * 2 == v_out_group) {
shoaib_ahmed 0:791a779d6220 342 /* Special case for 2h2v upsampling */
shoaib_ahmed 0:791a779d6220 343 upsample->methods[ci] = h2v2_upsample;
shoaib_ahmed 0:791a779d6220 344 } else if ((h_out_group % h_in_group) == 0 &&
shoaib_ahmed 0:791a779d6220 345 (v_out_group % v_in_group) == 0) {
shoaib_ahmed 0:791a779d6220 346 /* Generic integral-factors upsampling method */
shoaib_ahmed 0:791a779d6220 347 upsample->methods[ci] = int_upsample;
shoaib_ahmed 0:791a779d6220 348 upsample->h_expand[ci] = (UINT8) (h_out_group / h_in_group);
shoaib_ahmed 0:791a779d6220 349 upsample->v_expand[ci] = (UINT8) (v_out_group / v_in_group);
shoaib_ahmed 0:791a779d6220 350 } else
shoaib_ahmed 0:791a779d6220 351 ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);
shoaib_ahmed 0:791a779d6220 352 upsample->color_buf[ci] = (*cinfo->mem->alloc_sarray)
shoaib_ahmed 0:791a779d6220 353 ((j_common_ptr) cinfo, JPOOL_IMAGE,
shoaib_ahmed 0:791a779d6220 354 (JDIMENSION) jround_up((long) cinfo->output_width,
shoaib_ahmed 0:791a779d6220 355 (long) cinfo->max_h_samp_factor),
shoaib_ahmed 0:791a779d6220 356 (JDIMENSION) cinfo->max_v_samp_factor);
shoaib_ahmed 0:791a779d6220 357 }
shoaib_ahmed 0:791a779d6220 358 }