1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libjpeg/jcsample.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,527 @@
1.4 +/*
1.5 + * jcsample.c
1.6 + *
1.7 + * Copyright (C) 1991-1996, Thomas G. Lane.
1.8 + * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
1.9 + * This file is part of the Independent JPEG Group's software.
1.10 + * For conditions of distribution and use, see the accompanying README file.
1.11 + *
1.12 + * This file contains downsampling routines.
1.13 + *
1.14 + * Downsampling input data is counted in "row groups". A row group
1.15 + * is defined to be max_v_samp_factor pixel rows of each component,
1.16 + * from which the downsampler produces v_samp_factor sample rows.
1.17 + * A single row group is processed in each call to the downsampler module.
1.18 + *
1.19 + * The downsampler is responsible for edge-expansion of its output data
1.20 + * to fill an integral number of DCT blocks horizontally. The source buffer
1.21 + * may be modified if it is helpful for this purpose (the source buffer is
1.22 + * allocated wide enough to correspond to the desired output width).
1.23 + * The caller (the prep controller) is responsible for vertical padding.
1.24 + *
1.25 + * The downsampler may request "context rows" by setting need_context_rows
1.26 + * during startup. In this case, the input arrays will contain at least
1.27 + * one row group's worth of pixels above and below the passed-in data;
1.28 + * the caller will create dummy rows at image top and bottom by replicating
1.29 + * the first or last real pixel row.
1.30 + *
1.31 + * An excellent reference for image resampling is
1.32 + * Digital Image Warping, George Wolberg, 1990.
1.33 + * Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.
1.34 + *
1.35 + * The downsampling algorithm used here is a simple average of the source
1.36 + * pixels covered by the output pixel. The hi-falutin sampling literature
1.37 + * refers to this as a "box filter". In general the characteristics of a box
1.38 + * filter are not very good, but for the specific cases we normally use (1:1
1.39 + * and 2:1 ratios) the box is equivalent to a "triangle filter" which is not
1.40 + * nearly so bad. If you intend to use other sampling ratios, you'd be well
1.41 + * advised to improve this code.
1.42 + *
1.43 + * A simple input-smoothing capability is provided. This is mainly intended
1.44 + * for cleaning up color-dithered GIF input files (if you find it inadequate,
1.45 + * we suggest using an external filtering program such as pnmconvol). When
1.46 + * enabled, each input pixel P is replaced by a weighted sum of itself and its
1.47 + * eight neighbors. P's weight is 1-8*SF and each neighbor's weight is SF,
1.48 + * where SF = (smoothing_factor / 1024).
1.49 + * Currently, smoothing is only supported for 2h2v sampling factors.
1.50 + */
1.51 +
1.52 +#define JPEG_INTERNALS
1.53 +#include "jinclude.h"
1.54 +#include "jpeglib.h"
1.55 +#include "jsimd.h"
1.56 +
1.57 +
1.58 +/* Pointer to routine to downsample a single component */
1.59 +typedef JMETHOD(void, downsample1_ptr,
1.60 + (j_compress_ptr cinfo, jpeg_component_info * compptr,
1.61 + JSAMPARRAY input_data, JSAMPARRAY output_data));
1.62 +
1.63 +/* Private subobject */
1.64 +
1.65 +typedef struct {
1.66 + struct jpeg_downsampler pub; /* public fields */
1.67 +
1.68 + /* Downsampling method pointers, one per component */
1.69 + downsample1_ptr methods[MAX_COMPONENTS];
1.70 +} my_downsampler;
1.71 +
1.72 +typedef my_downsampler * my_downsample_ptr;
1.73 +
1.74 +
1.75 +/*
1.76 + * Initialize for a downsampling pass.
1.77 + */
1.78 +
1.79 +METHODDEF(void)
1.80 +start_pass_downsample (j_compress_ptr cinfo)
1.81 +{
1.82 + /* no work for now */
1.83 +}
1.84 +
1.85 +
1.86 +/*
1.87 + * Expand a component horizontally from width input_cols to width output_cols,
1.88 + * by duplicating the rightmost samples.
1.89 + */
1.90 +
1.91 +LOCAL(void)
1.92 +expand_right_edge (JSAMPARRAY image_data, int num_rows,
1.93 + JDIMENSION input_cols, JDIMENSION output_cols)
1.94 +{
1.95 + register JSAMPROW ptr;
1.96 + register JSAMPLE pixval;
1.97 + register int count;
1.98 + int row;
1.99 + int numcols = (int) (output_cols - input_cols);
1.100 +
1.101 + if (numcols > 0) {
1.102 + for (row = 0; row < num_rows; row++) {
1.103 + ptr = image_data[row] + input_cols;
1.104 + pixval = ptr[-1]; /* don't need GETJSAMPLE() here */
1.105 + for (count = numcols; count > 0; count--)
1.106 + *ptr++ = pixval;
1.107 + }
1.108 + }
1.109 +}
1.110 +
1.111 +
1.112 +/*
1.113 + * Do downsampling for a whole row group (all components).
1.114 + *
1.115 + * In this version we simply downsample each component independently.
1.116 + */
1.117 +
1.118 +METHODDEF(void)
1.119 +sep_downsample (j_compress_ptr cinfo,
1.120 + JSAMPIMAGE input_buf, JDIMENSION in_row_index,
1.121 + JSAMPIMAGE output_buf, JDIMENSION out_row_group_index)
1.122 +{
1.123 + my_downsample_ptr downsample = (my_downsample_ptr) cinfo->downsample;
1.124 + int ci;
1.125 + jpeg_component_info * compptr;
1.126 + JSAMPARRAY in_ptr, out_ptr;
1.127 +
1.128 + for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
1.129 + ci++, compptr++) {
1.130 + in_ptr = input_buf[ci] + in_row_index;
1.131 + out_ptr = output_buf[ci] + (out_row_group_index * compptr->v_samp_factor);
1.132 + (*downsample->methods[ci]) (cinfo, compptr, in_ptr, out_ptr);
1.133 + }
1.134 +}
1.135 +
1.136 +
1.137 +/*
1.138 + * Downsample pixel values of a single component.
1.139 + * One row group is processed per call.
1.140 + * This version handles arbitrary integral sampling ratios, without smoothing.
1.141 + * Note that this version is not actually used for customary sampling ratios.
1.142 + */
1.143 +
1.144 +METHODDEF(void)
1.145 +int_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
1.146 + JSAMPARRAY input_data, JSAMPARRAY output_data)
1.147 +{
1.148 + int inrow, outrow, h_expand, v_expand, numpix, numpix2, h, v;
1.149 + JDIMENSION outcol, outcol_h; /* outcol_h == outcol*h_expand */
1.150 + JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
1.151 + JSAMPROW inptr, outptr;
1.152 + INT32 outvalue;
1.153 +
1.154 + h_expand = cinfo->max_h_samp_factor / compptr->h_samp_factor;
1.155 + v_expand = cinfo->max_v_samp_factor / compptr->v_samp_factor;
1.156 + numpix = h_expand * v_expand;
1.157 + numpix2 = numpix/2;
1.158 +
1.159 + /* Expand input data enough to let all the output samples be generated
1.160 + * by the standard loop. Special-casing padded output would be more
1.161 + * efficient.
1.162 + */
1.163 + expand_right_edge(input_data, cinfo->max_v_samp_factor,
1.164 + cinfo->image_width, output_cols * h_expand);
1.165 +
1.166 + inrow = 0;
1.167 + for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
1.168 + outptr = output_data[outrow];
1.169 + for (outcol = 0, outcol_h = 0; outcol < output_cols;
1.170 + outcol++, outcol_h += h_expand) {
1.171 + outvalue = 0;
1.172 + for (v = 0; v < v_expand; v++) {
1.173 + inptr = input_data[inrow+v] + outcol_h;
1.174 + for (h = 0; h < h_expand; h++) {
1.175 + outvalue += (INT32) GETJSAMPLE(*inptr++);
1.176 + }
1.177 + }
1.178 + *outptr++ = (JSAMPLE) ((outvalue + numpix2) / numpix);
1.179 + }
1.180 + inrow += v_expand;
1.181 + }
1.182 +}
1.183 +
1.184 +
1.185 +/*
1.186 + * Downsample pixel values of a single component.
1.187 + * This version handles the special case of a full-size component,
1.188 + * without smoothing.
1.189 + */
1.190 +
1.191 +METHODDEF(void)
1.192 +fullsize_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
1.193 + JSAMPARRAY input_data, JSAMPARRAY output_data)
1.194 +{
1.195 + /* Copy the data */
1.196 + jcopy_sample_rows(input_data, 0, output_data, 0,
1.197 + cinfo->max_v_samp_factor, cinfo->image_width);
1.198 + /* Edge-expand */
1.199 + expand_right_edge(output_data, cinfo->max_v_samp_factor,
1.200 + cinfo->image_width, compptr->width_in_blocks * DCTSIZE);
1.201 +}
1.202 +
1.203 +
1.204 +/*
1.205 + * Downsample pixel values of a single component.
1.206 + * This version handles the common case of 2:1 horizontal and 1:1 vertical,
1.207 + * without smoothing.
1.208 + *
1.209 + * A note about the "bias" calculations: when rounding fractional values to
1.210 + * integer, we do not want to always round 0.5 up to the next integer.
1.211 + * If we did that, we'd introduce a noticeable bias towards larger values.
1.212 + * Instead, this code is arranged so that 0.5 will be rounded up or down at
1.213 + * alternate pixel locations (a simple ordered dither pattern).
1.214 + */
1.215 +
1.216 +METHODDEF(void)
1.217 +h2v1_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
1.218 + JSAMPARRAY input_data, JSAMPARRAY output_data)
1.219 +{
1.220 + int outrow;
1.221 + JDIMENSION outcol;
1.222 + JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
1.223 + register JSAMPROW inptr, outptr;
1.224 + register int bias;
1.225 +
1.226 + /* Expand input data enough to let all the output samples be generated
1.227 + * by the standard loop. Special-casing padded output would be more
1.228 + * efficient.
1.229 + */
1.230 + expand_right_edge(input_data, cinfo->max_v_samp_factor,
1.231 + cinfo->image_width, output_cols * 2);
1.232 +
1.233 + for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
1.234 + outptr = output_data[outrow];
1.235 + inptr = input_data[outrow];
1.236 + bias = 0; /* bias = 0,1,0,1,... for successive samples */
1.237 + for (outcol = 0; outcol < output_cols; outcol++) {
1.238 + *outptr++ = (JSAMPLE) ((GETJSAMPLE(*inptr) + GETJSAMPLE(inptr[1])
1.239 + + bias) >> 1);
1.240 + bias ^= 1; /* 0=>1, 1=>0 */
1.241 + inptr += 2;
1.242 + }
1.243 + }
1.244 +}
1.245 +
1.246 +
1.247 +/*
1.248 + * Downsample pixel values of a single component.
1.249 + * This version handles the standard case of 2:1 horizontal and 2:1 vertical,
1.250 + * without smoothing.
1.251 + */
1.252 +
1.253 +METHODDEF(void)
1.254 +h2v2_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
1.255 + JSAMPARRAY input_data, JSAMPARRAY output_data)
1.256 +{
1.257 + int inrow, outrow;
1.258 + JDIMENSION outcol;
1.259 + JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
1.260 + register JSAMPROW inptr0, inptr1, outptr;
1.261 + register int bias;
1.262 +
1.263 + /* Expand input data enough to let all the output samples be generated
1.264 + * by the standard loop. Special-casing padded output would be more
1.265 + * efficient.
1.266 + */
1.267 + expand_right_edge(input_data, cinfo->max_v_samp_factor,
1.268 + cinfo->image_width, output_cols * 2);
1.269 +
1.270 + inrow = 0;
1.271 + for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
1.272 + outptr = output_data[outrow];
1.273 + inptr0 = input_data[inrow];
1.274 + inptr1 = input_data[inrow+1];
1.275 + bias = 1; /* bias = 1,2,1,2,... for successive samples */
1.276 + for (outcol = 0; outcol < output_cols; outcol++) {
1.277 + *outptr++ = (JSAMPLE) ((GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
1.278 + GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1])
1.279 + + bias) >> 2);
1.280 + bias ^= 3; /* 1=>2, 2=>1 */
1.281 + inptr0 += 2; inptr1 += 2;
1.282 + }
1.283 + inrow += 2;
1.284 + }
1.285 +}
1.286 +
1.287 +
1.288 +#ifdef INPUT_SMOOTHING_SUPPORTED
1.289 +
1.290 +/*
1.291 + * Downsample pixel values of a single component.
1.292 + * This version handles the standard case of 2:1 horizontal and 2:1 vertical,
1.293 + * with smoothing. One row of context is required.
1.294 + */
1.295 +
1.296 +METHODDEF(void)
1.297 +h2v2_smooth_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
1.298 + JSAMPARRAY input_data, JSAMPARRAY output_data)
1.299 +{
1.300 + int inrow, outrow;
1.301 + JDIMENSION colctr;
1.302 + JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
1.303 + register JSAMPROW inptr0, inptr1, above_ptr, below_ptr, outptr;
1.304 + INT32 membersum, neighsum, memberscale, neighscale;
1.305 +
1.306 + /* Expand input data enough to let all the output samples be generated
1.307 + * by the standard loop. Special-casing padded output would be more
1.308 + * efficient.
1.309 + */
1.310 + expand_right_edge(input_data - 1, cinfo->max_v_samp_factor + 2,
1.311 + cinfo->image_width, output_cols * 2);
1.312 +
1.313 + /* We don't bother to form the individual "smoothed" input pixel values;
1.314 + * we can directly compute the output which is the average of the four
1.315 + * smoothed values. Each of the four member pixels contributes a fraction
1.316 + * (1-8*SF) to its own smoothed image and a fraction SF to each of the three
1.317 + * other smoothed pixels, therefore a total fraction (1-5*SF)/4 to the final
1.318 + * output. The four corner-adjacent neighbor pixels contribute a fraction
1.319 + * SF to just one smoothed pixel, or SF/4 to the final output; while the
1.320 + * eight edge-adjacent neighbors contribute SF to each of two smoothed
1.321 + * pixels, or SF/2 overall. In order to use integer arithmetic, these
1.322 + * factors are scaled by 2^16 = 65536.
1.323 + * Also recall that SF = smoothing_factor / 1024.
1.324 + */
1.325 +
1.326 + memberscale = 16384 - cinfo->smoothing_factor * 80; /* scaled (1-5*SF)/4 */
1.327 + neighscale = cinfo->smoothing_factor * 16; /* scaled SF/4 */
1.328 +
1.329 + inrow = 0;
1.330 + for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
1.331 + outptr = output_data[outrow];
1.332 + inptr0 = input_data[inrow];
1.333 + inptr1 = input_data[inrow+1];
1.334 + above_ptr = input_data[inrow-1];
1.335 + below_ptr = input_data[inrow+2];
1.336 +
1.337 + /* Special case for first column: pretend column -1 is same as column 0 */
1.338 + membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
1.339 + GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
1.340 + neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
1.341 + GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
1.342 + GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[2]) +
1.343 + GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[2]);
1.344 + neighsum += neighsum;
1.345 + neighsum += GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[2]) +
1.346 + GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[2]);
1.347 + membersum = membersum * memberscale + neighsum * neighscale;
1.348 + *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
1.349 + inptr0 += 2; inptr1 += 2; above_ptr += 2; below_ptr += 2;
1.350 +
1.351 + for (colctr = output_cols - 2; colctr > 0; colctr--) {
1.352 + /* sum of pixels directly mapped to this output element */
1.353 + membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
1.354 + GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
1.355 + /* sum of edge-neighbor pixels */
1.356 + neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
1.357 + GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
1.358 + GETJSAMPLE(inptr0[-1]) + GETJSAMPLE(inptr0[2]) +
1.359 + GETJSAMPLE(inptr1[-1]) + GETJSAMPLE(inptr1[2]);
1.360 + /* The edge-neighbors count twice as much as corner-neighbors */
1.361 + neighsum += neighsum;
1.362 + /* Add in the corner-neighbors */
1.363 + neighsum += GETJSAMPLE(above_ptr[-1]) + GETJSAMPLE(above_ptr[2]) +
1.364 + GETJSAMPLE(below_ptr[-1]) + GETJSAMPLE(below_ptr[2]);
1.365 + /* form final output scaled up by 2^16 */
1.366 + membersum = membersum * memberscale + neighsum * neighscale;
1.367 + /* round, descale and output it */
1.368 + *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
1.369 + inptr0 += 2; inptr1 += 2; above_ptr += 2; below_ptr += 2;
1.370 + }
1.371 +
1.372 + /* Special case for last column */
1.373 + membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
1.374 + GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
1.375 + neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
1.376 + GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
1.377 + GETJSAMPLE(inptr0[-1]) + GETJSAMPLE(inptr0[1]) +
1.378 + GETJSAMPLE(inptr1[-1]) + GETJSAMPLE(inptr1[1]);
1.379 + neighsum += neighsum;
1.380 + neighsum += GETJSAMPLE(above_ptr[-1]) + GETJSAMPLE(above_ptr[1]) +
1.381 + GETJSAMPLE(below_ptr[-1]) + GETJSAMPLE(below_ptr[1]);
1.382 + membersum = membersum * memberscale + neighsum * neighscale;
1.383 + *outptr = (JSAMPLE) ((membersum + 32768) >> 16);
1.384 +
1.385 + inrow += 2;
1.386 + }
1.387 +}
1.388 +
1.389 +
1.390 +/*
1.391 + * Downsample pixel values of a single component.
1.392 + * This version handles the special case of a full-size component,
1.393 + * with smoothing. One row of context is required.
1.394 + */
1.395 +
1.396 +METHODDEF(void)
1.397 +fullsize_smooth_downsample (j_compress_ptr cinfo, jpeg_component_info *compptr,
1.398 + JSAMPARRAY input_data, JSAMPARRAY output_data)
1.399 +{
1.400 + int outrow;
1.401 + JDIMENSION colctr;
1.402 + JDIMENSION output_cols = compptr->width_in_blocks * DCTSIZE;
1.403 + register JSAMPROW inptr, above_ptr, below_ptr, outptr;
1.404 + INT32 membersum, neighsum, memberscale, neighscale;
1.405 + int colsum, lastcolsum, nextcolsum;
1.406 +
1.407 + /* Expand input data enough to let all the output samples be generated
1.408 + * by the standard loop. Special-casing padded output would be more
1.409 + * efficient.
1.410 + */
1.411 + expand_right_edge(input_data - 1, cinfo->max_v_samp_factor + 2,
1.412 + cinfo->image_width, output_cols);
1.413 +
1.414 + /* Each of the eight neighbor pixels contributes a fraction SF to the
1.415 + * smoothed pixel, while the main pixel contributes (1-8*SF). In order
1.416 + * to use integer arithmetic, these factors are multiplied by 2^16 = 65536.
1.417 + * Also recall that SF = smoothing_factor / 1024.
1.418 + */
1.419 +
1.420 + memberscale = 65536L - cinfo->smoothing_factor * 512L; /* scaled 1-8*SF */
1.421 + neighscale = cinfo->smoothing_factor * 64; /* scaled SF */
1.422 +
1.423 + for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
1.424 + outptr = output_data[outrow];
1.425 + inptr = input_data[outrow];
1.426 + above_ptr = input_data[outrow-1];
1.427 + below_ptr = input_data[outrow+1];
1.428 +
1.429 + /* Special case for first column */
1.430 + colsum = GETJSAMPLE(*above_ptr++) + GETJSAMPLE(*below_ptr++) +
1.431 + GETJSAMPLE(*inptr);
1.432 + membersum = GETJSAMPLE(*inptr++);
1.433 + nextcolsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(*below_ptr) +
1.434 + GETJSAMPLE(*inptr);
1.435 + neighsum = colsum + (colsum - membersum) + nextcolsum;
1.436 + membersum = membersum * memberscale + neighsum * neighscale;
1.437 + *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
1.438 + lastcolsum = colsum; colsum = nextcolsum;
1.439 +
1.440 + for (colctr = output_cols - 2; colctr > 0; colctr--) {
1.441 + membersum = GETJSAMPLE(*inptr++);
1.442 + above_ptr++; below_ptr++;
1.443 + nextcolsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(*below_ptr) +
1.444 + GETJSAMPLE(*inptr);
1.445 + neighsum = lastcolsum + (colsum - membersum) + nextcolsum;
1.446 + membersum = membersum * memberscale + neighsum * neighscale;
1.447 + *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
1.448 + lastcolsum = colsum; colsum = nextcolsum;
1.449 + }
1.450 +
1.451 + /* Special case for last column */
1.452 + membersum = GETJSAMPLE(*inptr);
1.453 + neighsum = lastcolsum + (colsum - membersum) + colsum;
1.454 + membersum = membersum * memberscale + neighsum * neighscale;
1.455 + *outptr = (JSAMPLE) ((membersum + 32768) >> 16);
1.456 +
1.457 + }
1.458 +}
1.459 +
1.460 +#endif /* INPUT_SMOOTHING_SUPPORTED */
1.461 +
1.462 +
1.463 +/*
1.464 + * Module initialization routine for downsampling.
1.465 + * Note that we must select a routine for each component.
1.466 + */
1.467 +
1.468 +GLOBAL(void)
1.469 +jinit_downsampler (j_compress_ptr cinfo)
1.470 +{
1.471 + my_downsample_ptr downsample;
1.472 + int ci;
1.473 + jpeg_component_info * compptr;
1.474 + boolean smoothok = TRUE;
1.475 +
1.476 + downsample = (my_downsample_ptr)
1.477 + (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
1.478 + SIZEOF(my_downsampler));
1.479 + cinfo->downsample = (struct jpeg_downsampler *) downsample;
1.480 + downsample->pub.start_pass = start_pass_downsample;
1.481 + downsample->pub.downsample = sep_downsample;
1.482 + downsample->pub.need_context_rows = FALSE;
1.483 +
1.484 + if (cinfo->CCIR601_sampling)
1.485 + ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);
1.486 +
1.487 + /* Verify we can handle the sampling factors, and set up method pointers */
1.488 + for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
1.489 + ci++, compptr++) {
1.490 + if (compptr->h_samp_factor == cinfo->max_h_samp_factor &&
1.491 + compptr->v_samp_factor == cinfo->max_v_samp_factor) {
1.492 +#ifdef INPUT_SMOOTHING_SUPPORTED
1.493 + if (cinfo->smoothing_factor) {
1.494 + downsample->methods[ci] = fullsize_smooth_downsample;
1.495 + downsample->pub.need_context_rows = TRUE;
1.496 + } else
1.497 +#endif
1.498 + downsample->methods[ci] = fullsize_downsample;
1.499 + } else if (compptr->h_samp_factor * 2 == cinfo->max_h_samp_factor &&
1.500 + compptr->v_samp_factor == cinfo->max_v_samp_factor) {
1.501 + smoothok = FALSE;
1.502 + if (jsimd_can_h2v1_downsample())
1.503 + downsample->methods[ci] = jsimd_h2v1_downsample;
1.504 + else
1.505 + downsample->methods[ci] = h2v1_downsample;
1.506 + } else if (compptr->h_samp_factor * 2 == cinfo->max_h_samp_factor &&
1.507 + compptr->v_samp_factor * 2 == cinfo->max_v_samp_factor) {
1.508 +#ifdef INPUT_SMOOTHING_SUPPORTED
1.509 + if (cinfo->smoothing_factor) {
1.510 + downsample->methods[ci] = h2v2_smooth_downsample;
1.511 + downsample->pub.need_context_rows = TRUE;
1.512 + } else
1.513 +#endif
1.514 + if (jsimd_can_h2v2_downsample())
1.515 + downsample->methods[ci] = jsimd_h2v2_downsample;
1.516 + else
1.517 + downsample->methods[ci] = h2v2_downsample;
1.518 + } else if ((cinfo->max_h_samp_factor % compptr->h_samp_factor) == 0 &&
1.519 + (cinfo->max_v_samp_factor % compptr->v_samp_factor) == 0) {
1.520 + smoothok = FALSE;
1.521 + downsample->methods[ci] = int_downsample;
1.522 + } else
1.523 + ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);
1.524 + }
1.525 +
1.526 +#ifdef INPUT_SMOOTHING_SUPPORTED
1.527 + if (cinfo->smoothing_factor && !smoothok)
1.528 + TRACEMS(cinfo, 0, JTRC_SMOOTH_NOTIMPL);
1.529 +#endif
1.530 +}
