git.sesse.net Git - qscale/blob - libqscale.c

   1 /*
   2  * qscale: Quick, high-quality JPEG-to-JPEG scaler.
   3  * Copyright (C) 2008 Steinar H. Gunderson <sgunderson@bigfoot.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, version 2 of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  17  */
  18
  19 #include <math.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <malloc.h>
  24
  25 #include "libqscale.h"
  26
  27 /* The number of pixels to process at a time when scaling vertically. */
  28 #define CACHE_LINE_FACTOR 16
  29
  30 /* Whether to use SSE for horizontal scaling or not (requires SSE3). */
  31 #define USE_HORIZONTAL_SSE 1
  32
  33 /* Whether to use SSE for vertical scaling or not (requires only SSE1). */
  34 #define USE_VERTICAL_SSE 1
  35
  36 #if USE_VERTICAL_SSE
  37 #undef CACHE_LINE_FACTOR
  38 #define CACHE_LINE_FACTOR 16
  39 #endif
  40
  41 #ifndef M_PI
  42 #define M_PI 3.14159265358979323846264
  43 #endif
  44
  45 #if USE_VERTICAL_SSE || USE_HORIZONTAL_SSE
  46 typedef float v4sf __attribute__((vector_size(16)));
  47 typedef int v4si __attribute__((vector_size(16)));
  48 typedef short v8hi __attribute__((vector_size(16)));
  49 typedef char v16qi __attribute__((vector_size(16)));
  50 #endif
  51
  52 qscale_img *qscale_load_jpeg(const char *filename)
  53 {
  54         FILE *file = fopen(filename, "rb");
  55         qscale_img *img;
  56         if (file == NULL) {
  57                 return NULL;
  58         }
  59
  60         img = qscale_load_jpeg_from_stdio(file);
  61
  62         fclose(file);
  63         return img;
  64 }
  65
  66 qscale_img *qscale_load_jpeg_from_stdio(FILE *file)
  67 {
  68         qscale_img *img = (qscale_img *)malloc(sizeof(qscale_img));
  69         if (img == NULL) {
  70                 return NULL;
  71         }
  72
  73         img->data_y = img->data_cb = img->data_cr = NULL;
  74
  75         /* FIXME: Better error handling here (ie., return NULL). */
  76         struct jpeg_decompress_struct dinfo;
  77         struct jpeg_error_mgr jerr;
  78         dinfo.err = jpeg_std_error(&jerr);
  79         jpeg_create_decompress(&dinfo);
  80         jpeg_stdio_src(&dinfo, file);
  81         jpeg_read_header(&dinfo, TRUE);
  82         dinfo.raw_data_out = TRUE;
  83         jpeg_start_decompress(&dinfo);
  84
  85         if (dinfo.num_components != 1 && dinfo.num_components != 3) {
  86                 qscale_destroy(img);
  87                 return NULL;
  88         }
  89         img->num_components = dinfo.num_components;
  90
  91         img->width = dinfo.image_width;
  92         img->height = dinfo.image_height;
  93
  94         img->w0 = dinfo.image_width * dinfo.comp_info[0].h_samp_factor / dinfo.max_h_samp_factor;
  95         img->h0 = dinfo.image_height * dinfo.comp_info[0].v_samp_factor / dinfo.max_v_samp_factor;
  96
  97         if (img->num_components == 3) {
  98                 img->w1 = dinfo.image_width * dinfo.comp_info[1].h_samp_factor / dinfo.max_h_samp_factor;
  99                 img->h1 = dinfo.image_height * dinfo.comp_info[1].v_samp_factor / dinfo.max_v_samp_factor;
 100
 101                 img->w2 = dinfo.image_width * dinfo.comp_info[2].h_samp_factor / dinfo.max_h_samp_factor;
 102                 img->h2 = dinfo.image_height * dinfo.comp_info[2].v_samp_factor / dinfo.max_v_samp_factor;
 103         }
 104
 105         img->samp_h0 = dinfo.comp_info[0].h_samp_factor;
 106         img->samp_v0 = dinfo.comp_info[0].v_samp_factor;
 107
 108         if (img->num_components == 3) {
 109                 img->samp_h1 = dinfo.comp_info[1].h_samp_factor;
 110                 img->samp_v1 = dinfo.comp_info[1].v_samp_factor;
 111
 112                 img->samp_h2 = dinfo.comp_info[2].h_samp_factor;
 113                 img->samp_v2 = dinfo.comp_info[2].v_samp_factor;
 114         }
 115
 116         img->data_y  = (JSAMPLE*)memalign(16, dinfo.comp_info[0].height_in_blocks * dinfo.comp_info[0].width_in_blocks * DCTSIZE * DCTSIZE);
 117         if (img->data_y == NULL) {
 118                 qscale_destroy(img);
 119                 return NULL;
 120         }
 121
 122         if (img->num_components == 3) {
 123                 img->data_cb = (JSAMPLE*)memalign(16, dinfo.comp_info[1].height_in_blocks * dinfo.comp_info[1].width_in_blocks * DCTSIZE * DCTSIZE);
 124                 img->data_cr = (JSAMPLE*)memalign(16, dinfo.comp_info[2].height_in_blocks * dinfo.comp_info[2].width_in_blocks * DCTSIZE * DCTSIZE);
 125                 if (img->data_cb == NULL || img->data_cr == NULL) {
 126                         qscale_destroy(img);
 127                         return NULL;
 128                 }
 129         }
 130
 131         int total_lines = 0, blocks = 0;
 132         while (total_lines < dinfo.comp_info[0].height_in_blocks * DCTSIZE) {
 133                 unsigned max_lines = dinfo.max_v_samp_factor * DCTSIZE;
 134
 135                 JSAMPROW y_row_ptrs[max_lines];
 136                 JSAMPROW cb_row_ptrs[max_lines];
 137                 JSAMPROW cr_row_ptrs[max_lines];
 138                 JSAMPROW* ptrs[] = { y_row_ptrs, cb_row_ptrs, cr_row_ptrs };
 139
 140                 int i;
 141                 for (i = 0; i < max_lines; ++i) {
 142                         y_row_ptrs[i]  = img->data_y  + (i+blocks*DCTSIZE*dinfo.comp_info[0].v_samp_factor) * dinfo.comp_info[0].width_in_blocks * DCTSIZE;
 143                         if (img->num_components == 3) {
 144                                 cb_row_ptrs[i] = img->data_cb + (i+blocks*DCTSIZE*dinfo.comp_info[1].v_samp_factor) * dinfo.comp_info[1].width_in_blocks * DCTSIZE;
 145                                 cr_row_ptrs[i] = img->data_cr + (i+blocks*DCTSIZE*dinfo.comp_info[2].v_samp_factor) * dinfo.comp_info[2].width_in_blocks * DCTSIZE;
 146                         }
 147                 }
 148
 149                 total_lines += max_lines;
 150                 ++blocks;
 151
 152                 if (jpeg_read_raw_data(&dinfo, ptrs, max_lines) == 0)
 153                         break;
 154         }
 155
 156         jpeg_destroy_decompress(&dinfo);
 157         return img;
 158 }
 159
 160 void qscale_destroy(qscale_img *img)
 161 {
 162         free(img->data_y);
 163         free(img->data_cb);
 164         free(img->data_cr);
 165         free(img);
 166 }
 167
 168
 169 static double sinc(double x)
 170 {
 171         static const double cutoff = 1.220703668e-4;  /* sqrt(sqrt(eps)) */
 172
 173         if (abs(x) < cutoff) {
 174                 /* For small |x|, use Taylor series instead */
 175                 const double x2 = x * x;
 176                 const double x4 = x2 * x2;
 177
 178                 return 1.0 - x2 / 6.0 + x4 / 120.0;
 179         } else {
 180                 return sin(x) / x;
 181         }
 182 }
 183
 184 static double lanczos_tap(double x)
 185 {
 186         if (x < -3.0 || x > 3.0)
 187                 return 0.0;
 188         if (x < 0.0)
 189                 return sinc(-x*M_PI) * sinc(-x*M_PI / 3.0);
 190         else
 191                 return sinc(x*M_PI) * sinc(x*M_PI / 3.0);
 192 }
 193
 194 static double mitchell_tap(double x)
 195 {
 196         const double b = 1.0 / 3.0;
 197         const double c = 1.0 / 3.0;
 198         const double p0 = (  6.0 -  2.0*b         ) / 6.0;
 199         const double p2 = (-18.0 + 12.0*b +  6.0*c) / 6.0;
 200         const double p3 = ( 12.0 -  9.0*b -  6.0*c) / 6.0;
 201         const double q0 = (         8.0*b + 24.0*c) / 6.0;
 202         const double q1 = (      - 12.0*b - 48.0*c) / 6.0;
 203         const double q2 = (         6.0*b + 30.0*c) / 6.0;
 204         const double q3 = (      -      b -  6.0*c) / 6.0;
 205
 206         if (x < -2.0) {
 207                 return 0.0;
 208         } else if (x < -1.0) {
 209                 return q0 - x * (q1 - x * (q2 - x * q3));
 210         } else if (x < 0.0) {
 211                 return p0 + x * x * (p2 - x * p3);
 212         } else if (x < 1.0) {
 213                 return p0 + x * x * (p2 + x * p3);
 214         } else if (x < 2.0) {
 215                 return q0 + x * (q1 + x * (q2 + x * q3));
 216         } else {
 217                 return 0.0;
 218         }
 219 }
 220
 221 struct pix_desc {
 222         unsigned start, end;
 223         unsigned startcoeff;
 224 };
 225
 226 static void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw, unsigned sstride, unsigned dstride, enum qscale_scaling_filter scaling_filter)
 227 {
 228         struct pix_desc *pd = (struct pix_desc *)malloc(nw * sizeof(struct pix_desc));
 229         int size_coeffs = 8;
 230         float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
 231         int num_coeffs = 0;
 232         int x, y;
 233         double sf = (double)w / (double)nw;
 234         double support;
 235
 236         if (scaling_filter == LANCZOS) {
 237                 support = (w > nw) ? (3.0 * sf) : (3.0 / sf);
 238         } else {  /* Mitchell */
 239                 support = (w > nw) ? (2.0 * sf) : (2.0 / sf);
 240         }
 241
 242         /* calculate the filter */
 243         for (x = 0; x < nw; ++x) {
 244                 int start = ceil(x * sf - support);
 245                 int end = floor(x * sf + support);
 246                 int sx;
 247                 double sum = 0.0;
 248
 249                 if (start < 0) {
 250                         start = 0;
 251                 }
 252                 if (end > w - 1) {
 253                         end = w - 1;
 254                 }
 255
 256 #if USE_HORIZONTAL_SSE
 257                 /* round up so we get a multiple of four for the SSE code */
 258                 int num = (end - start + 1);
 259                 if (num % 4 != 0) {
 260                         /* prefer aligning it if possible */
 261                         if (start % 4 != 0 && start % 4 <= num % 4) {
 262                                 num += start % 4;
 263                                 start -= start % 4;
 264                         }
 265                         if (num % 4 != 0) {
 266                                 end += 4 - (num % 4);
 267                         }
 268                 }
 269 #endif
 270
 271                 pd[x].start = start;
 272                 pd[x].end = end;
 273                 pd[x].startcoeff = num_coeffs;
 274
 275                 for (sx = start; sx <= end; ++sx) {
 276                         double nd = (w > nw) ? (sx/sf - x) : (sx - x*sf);
 277                         double f;
 278                         if (scaling_filter == LANCZOS) {
 279                                 f = lanczos_tap(nd);
 280                         } else {  /* Mitchell */
 281                                 f = mitchell_tap(nd);
 282                         }
 283                         if (num_coeffs == size_coeffs) {
 284                                 size_coeffs <<= 1;
 285                                 coeffs = (float *)realloc(coeffs, size_coeffs * sizeof(float));
 286                         }
 287
 288                         coeffs[num_coeffs++] = f;
 289                         sum += f;
 290                 }
 291
 292                 for (sx = start; sx <= end; ++sx) {
 293                         coeffs[pd[x].startcoeff + sx - start] /= sum;
 294                 }
 295         }
 296
 297         for (y = 0; y < h; ++y) {
 298                 float *sptr = pix + y*sstride;
 299                 unsigned char *dptr = npix + y*dstride;
 300                 unsigned char ch;
 301                 for (x = 0; x < nw; ++x) {
 302 #if USE_HORIZONTAL_SSE
 303                         int result;
 304                         float acc;
 305                         long tmp;
 306                         static const float low = 0.0, high = 255.0;
 307                         __asm__ (
 308                                 "pxor %1, %1               \n"
 309                                 "xor %2, %2                \n"
 310                                 "0:                        \n"
 311                                 "movups (%4,%2),%%xmm1     \n"
 312                                 "movups (%3,%2),%%xmm2     \n"
 313                                 "mulps %%xmm2,%%xmm1       \n"
 314                                 "addps %%xmm1,%1           \n"
 315                                 "add $16,%2                \n"
 316                                 "dec %5                    \n"
 317                                 "jnz 0b                    \n"
 318                                 "haddps %1,%1              \n"
 319                                 "haddps %1,%1              \n"
 320                                 "maxss %6,%1               \n"
 321                                 "minss %7,%1               \n"
 322                                 "cvtss2si %1,%0            \n"
 323                                 : "=r" (result),
 324                                   "=&x" (acc),
 325                                   "=&r" (tmp)
 326                                 : "r" (&coeffs[pd[x].startcoeff]),
 327                                   "r" (&sptr[pd[x].start]),
 328                                   "r" ((pd[x].end - pd[x].start + 1)/4),
 329                                   "m" (low),
 330                                   "m" (high)
 331                                 : "memory", "xmm1", "xmm2"
 332                         );
 333
 334                         *dptr++ = (unsigned char)result;
 335 #else
 336                         float acc = 0.0;
 337                         float *cf = &coeffs[pd[x].startcoeff];
 338                         unsigned sx;
 339
 340                         for (sx = pd[x].start; sx <= pd[x].end; ++sx) {
 341                                 acc += sptr[sx] * *cf++;
 342                         }
 343
 344                         if (acc < 0.0)
 345                                 ch = 0;
 346                         else if (acc > 255.0)
 347                                 ch = 255;
 348                         else
 349                                 ch = (unsigned char)acc;
 350                         *dptr++ = ch;
 351 #endif
 352                 }
 353                 ch = dptr[-1];
 354                 for ( ; x < dstride; ++x) {
 355                         *dptr++ = ch;
 356                 }
 357         }
 358 }
 359
 360 static void vscale(unsigned char *pix, float *npix, unsigned w, unsigned h, unsigned nh, unsigned dstride, enum qscale_scaling_filter scaling_filter)
 361 {
 362         struct pix_desc *pd = (struct pix_desc *)malloc(nh * sizeof(struct pix_desc));
 363         int size_coeffs = 8;
 364         float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
 365         int num_coeffs = 0;
 366         int x, y, sy;
 367         double sf = (double)h / (double)nh;
 368         double support;
 369
 370         if (scaling_filter == LANCZOS) {
 371                 support = (h > nh) ? (3.0 * sf) : (3.0 / sf);
 372         } else {  /* Mitchell */
 373                 support = (h > nh) ? (2.0 * sf) : (2.0 / sf);
 374         }
 375
 376         /* calculate the filter */
 377         for (y = 0; y < nh; ++y) {
 378                 int start = ceil(y * sf - support);
 379                 int end = floor(y * sf + support);
 380                 double sum = 0.0;
 381
 382                 if (start < 0) {
 383                         start = 0;
 384                 }
 385                 if (end > h - 1) {
 386                         end = h - 1;
 387                 }
 388
 389                 pd[y].start = start;
 390                 pd[y].end = end;
 391                 pd[y].startcoeff = num_coeffs;
 392
 393                 for (sy = start; sy <= end; ++sy) {
 394                         double nd = (h > nh) ? (sy/sf - y) : (sy - y*sf);
 395                         double f;
 396                         if (scaling_filter == LANCZOS) {
 397                                 f = lanczos_tap(nd);
 398                         } else {  /* Mitchell */
 399                                 f = mitchell_tap(nd);
 400                         }
 401                         if (num_coeffs == size_coeffs) {
 402                                 size_coeffs <<= 1;
 403                                 coeffs = (float *)realloc(coeffs, size_coeffs * sizeof(float));
 404                         }
 405
 406                         coeffs[num_coeffs++] = f;
 407                         sum += f;
 408                 }
 409
 410                 for (sy = start; sy <= end; ++sy) {
 411                         coeffs[pd[y].startcoeff + sy - start] /= sum;
 412                 }
 413         }
 414
 415 #if CACHE_LINE_FACTOR > 1
 416         for (x = 0; x < (w/CACHE_LINE_FACTOR) * CACHE_LINE_FACTOR; x += CACHE_LINE_FACTOR) {
 417                 unsigned char *sptr = pix + x;
 418                 float *dptr = npix + x;
 419                 for (y = 0; y < nh; ++y) {
 420 #if USE_VERTICAL_SSE
 421                         /* A zero is useful during unpacking. */
 422                         static const v4sf zero = { 0.0f, 0.0f, 0.0f, 0.0f };
 423                         const unsigned char *sptr_xmm = &sptr[pd[y].start * w];
 424                         const float *coeffptr = &coeffs[pd[y].startcoeff];
 425                         const int filter_len = pd[y].end - pd[y].start + 1;
 426                         int i;
 427
 428                         v4sf acc0 = { 0.0f, 0.0f, 0.0f, 0.0f };
 429                         v4sf acc1 = { 0.0f, 0.0f, 0.0f, 0.0f };
 430                         v4sf acc2 = { 0.0f, 0.0f, 0.0f, 0.0f };
 431                         v4sf acc3 = { 0.0f, 0.0f, 0.0f, 0.0f };
 432
 433                         for (i = 0; i < filter_len; ++i, ++coeffptr, sptr_xmm += w) {
 434                                 __builtin_prefetch(sptr_xmm + w, 0);
 435                                 v16qi src = (v16qi)__builtin_ia32_loadups((float*)sptr_xmm);
 436
 437                                 // unpack into words
 438                                 v8hi src_lo = (v8hi)__builtin_ia32_punpcklbw128(src, (v16qi)zero);
 439                                 v8hi src_hi = (v8hi)__builtin_ia32_punpckhbw128(src, (v16qi)zero);
 440
 441                                 // unpack into dwords, convert to floats
 442                                 v4si src0_i = (v4si)__builtin_ia32_punpcklwd128(src_lo, (v8hi)zero);
 443                                 v4si src1_i = (v4si)__builtin_ia32_punpckhwd128(src_lo, (v8hi)zero);
 444                                 v4si src2_i = (v4si)__builtin_ia32_punpcklwd128(src_hi, (v8hi)zero);
 445                                 v4si src3_i = (v4si)__builtin_ia32_punpckhwd128(src_hi, (v8hi)zero);
 446
 447                                 v4sf src0 = __builtin_ia32_cvtdq2ps(src0_i);
 448                                 v4sf src1 = __builtin_ia32_cvtdq2ps(src1_i);
 449                                 v4sf src2 = __builtin_ia32_cvtdq2ps(src2_i);
 450                                 v4sf src3 = __builtin_ia32_cvtdq2ps(src3_i);
 451
 452                                 // fetch the coefficient, and replicate it
 453                                 v4sf coeff = { *coeffptr, *coeffptr, *coeffptr, *coeffptr };
 454
 455                                 // do the actual muladds
 456                                 acc0 = __builtin_ia32_addps(acc0, __builtin_ia32_mulps(src0, coeff));
 457                                 acc1 = __builtin_ia32_addps(acc1, __builtin_ia32_mulps(src1, coeff));
 458                                 acc2 = __builtin_ia32_addps(acc2, __builtin_ia32_mulps(src2, coeff));
 459                                 acc3 = __builtin_ia32_addps(acc3, __builtin_ia32_mulps(src3, coeff));
 460                         }
 461
 462                         *(v4sf *)(&dptr[0]) = acc0;
 463                         *(v4sf *)(&dptr[4]) = acc1;
 464                         *(v4sf *)(&dptr[8]) = acc2;
 465                         *(v4sf *)(&dptr[12]) = acc3;
 466 #else
 467                         int i;
 468                         float acc[CACHE_LINE_FACTOR];
 469                         for (i = 0; i < CACHE_LINE_FACTOR; ++i)
 470                                 acc[i] = 0.0;
 471                         float *cf = &coeffs[pd[y].startcoeff];
 472                         unsigned sy;
 473
 474                         for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
 475                                 for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
 476                                         acc[i] += sptr[sy * w + i] * *cf;
 477                                 }
 478                                 ++cf;
 479                         }
 480
 481                         for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
 482                                 dptr[i] = acc[i];
 483                         }
 484 #endif
 485                         dptr += dstride;
 486                 }
 487         }
 488         for (x = (x/CACHE_LINE_FACTOR)*CACHE_LINE_FACTOR; x < w; ++x) {
 489 #else
 490         for (x = 0; x < w; ++x) {
 491 #endif
 492                 unsigned char *sptr = pix + x;
 493                 float *dptr = npix + x;
 494                 for (y = 0; y < nh; ++y) {
 495                         float acc = 0.0;
 496                         float *cf = &coeffs[pd[y].startcoeff];
 497                         unsigned sy;
 498
 499                         for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
 500                                 acc += sptr[sy * w] * *cf++;
 501                         }
 502
 503                         *dptr = acc;
 504                         dptr += dstride;
 505                 }
 506         }
 507 }
 508
 509 qscale_img *qscale_clone(const qscale_img *img)
 510 {
 511         qscale_img *dst = (qscale_img *)malloc(sizeof(qscale_img));
 512         if (dst == NULL) {
 513                 return NULL;
 514         }
 515
 516         *dst = *img;
 517
 518         unsigned dstride0 = (dst->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 519         unsigned dstride1 = (dst->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 520         unsigned dstride2 = (dst->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 521
 522         /* FIXME: handle out-of-memory gracefully */
 523         {
 524                 dst->data_y = (unsigned char *)malloc(dst->h0 * dstride0);
 525                 memcpy(dst->data_y, img->data_y, dst->h0 * dstride0);
 526         }
 527         {
 528                 dst->data_cb = (unsigned char *)malloc(dst->h1 * dstride1);
 529                 memcpy(dst->data_cb, img->data_cb, dst->h1 * dstride1);
 530         }
 531         {
 532                 dst->data_cr = (unsigned char *)malloc(dst->h2 * dstride2);
 533                 memcpy(dst->data_cr, img->data_cr, dst->h2 * dstride2);
 534         }
 535
 536         return dst;
 537 }
 538
 539 qscale_img *qscale_scale(qscale_img *src, unsigned width, unsigned height, unsigned samp_h0, unsigned samp_v0, unsigned samp_h1, unsigned samp_v1, unsigned samp_h2, unsigned samp_v2, enum qscale_scaling_filter scaling_filter)
 540 {
 541         qscale_img *dst = (qscale_img *)malloc(sizeof(qscale_img));
 542         if (dst == NULL) {
 543                 return NULL;
 544         }
 545
 546         dst->width = width;
 547         dst->height = height;
 548         dst->num_components = src->num_components;
 549
 550         unsigned max_samp_h, max_samp_v;
 551         max_samp_h = samp_h0;
 552         if (src->num_components == 3) {
 553                 if (samp_h1 > max_samp_h)
 554                         max_samp_h = samp_h1;
 555                 if (samp_h2 > max_samp_h)
 556                         max_samp_h = samp_h2;
 557         }
 558
 559         max_samp_v = samp_v0;
 560         if (src->num_components == 3) {
 561                 if (samp_v1 > max_samp_v)
 562                         max_samp_v = samp_v1;
 563                 if (samp_v2 > max_samp_v)
 564                         max_samp_v = samp_v2;
 565         }
 566
 567         dst->w0 = width * samp_h0 / max_samp_h;
 568         dst->h0 = height * samp_v0 / max_samp_v;
 569
 570         if (src->num_components == 3) {
 571                 dst->w1 = width * samp_h1 / max_samp_h;
 572                 dst->h1 = height * samp_v1 / max_samp_v;
 573
 574                 dst->w2 = width * samp_h2 / max_samp_h;
 575                 dst->h2 = height * samp_v2 / max_samp_v;
 576         }
 577
 578         dst->samp_h0 = samp_h0;
 579         dst->samp_v0 = samp_v0;
 580
 581         if (src->num_components == 3) {
 582                 dst->samp_h1 = samp_h1;
 583                 dst->samp_v1 = samp_v1;
 584
 585                 dst->samp_h2 = samp_h2;
 586                 dst->samp_v2 = samp_v2;
 587         }
 588
 589         unsigned dstride0 = (dst->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 590         unsigned dstride1 = (dst->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 591         unsigned dstride2 = (dst->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 592
 593         unsigned sstride0 = (src->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 594         unsigned sstride1 = (src->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 595         unsigned sstride2 = (src->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 596
 597         /* FIXME: handle out-of-memory gracefully */
 598         {
 599                 float *npix = (float*)memalign(16, sstride0 * dst->h0 * sizeof(float));
 600                 vscale(src->data_y, npix, sstride0, src->h0, dst->h0, sstride0, scaling_filter);
 601                 dst->data_y = (unsigned char *)malloc(dst->h0 * dstride0);
 602                 hscale(npix, dst->data_y, src->w0, dst->h0, dst->w0, sstride0, dstride0, scaling_filter);
 603                 free(npix);
 604         }
 605         if (src->num_components == 3) {
 606                 {
 607                         float *npix = (float*)memalign(16, sstride1 * dst->h1 * sizeof(float));
 608                         vscale(src->data_cr, npix, sstride1, src->h1, dst->h1, sstride1, scaling_filter);
 609                         dst->data_cr = (unsigned char *)malloc(dst->h1 * dstride1);
 610                         hscale(npix, dst->data_cr, src->w1, dst->h1, dst->w1, sstride1, dstride1, scaling_filter);
 611                         free(npix);
 612                 }
 613                 {
 614                         float *npix = (float*)memalign(16, sstride2 * dst->h2 * sizeof(float));
 615                         vscale(src->data_cb, npix, sstride2, src->h2, dst->h2, sstride2, scaling_filter);
 616                         dst->data_cb = (unsigned char *)malloc(dst->h2 * dstride2);
 617                         hscale(npix, dst->data_cb, src->w2, dst->h2, dst->w2, sstride2, dstride2, scaling_filter);
 618                         free(npix);
 619                 }
 620         }
 621
 622         return dst;
 623 }
 624
 625 int qscale_save_jpeg(const qscale_img *img, const char *filename, unsigned jpeg_quality, enum qscale_jpeg_mode jpeg_mode)
 626 {
 627         FILE *file = fopen(filename, "wb");
 628         if (file == NULL) {
 629                 return -1;
 630         }
 631
 632         int err = qscale_save_jpeg_to_stdio(img, file, jpeg_quality, jpeg_mode);
 633
 634         fclose(file);
 635         return err;
 636 }
 637
 638 int qscale_save_jpeg_to_stdio(const qscale_img *img, FILE *file, unsigned jpeg_quality, enum qscale_jpeg_mode jpeg_mode)
 639 {
 640         struct jpeg_compress_struct cinfo;
 641         struct jpeg_error_mgr jerr;
 642         cinfo.err = jpeg_std_error(&jerr);
 643         jpeg_create_compress(&cinfo);
 644         jpeg_stdio_dest(&cinfo, file);
 645         cinfo.input_components = img->num_components;
 646         jpeg_set_defaults(&cinfo);
 647         jpeg_set_quality(&cinfo, jpeg_quality, FALSE);
 648
 649         if (jpeg_mode == PROGRESSIVE) {
 650                 jpeg_simple_progression(&cinfo);
 651         }
 652
 653         cinfo.image_width = img->width;
 654         cinfo.image_height = img->height;
 655         cinfo.raw_data_in = TRUE;
 656         if (img->num_components == 3) {
 657                 jpeg_set_colorspace(&cinfo, JCS_YCbCr);
 658         } else {
 659                 jpeg_set_colorspace(&cinfo, JCS_GRAYSCALE);
 660         }
 661         cinfo.comp_info[0].h_samp_factor = img->samp_h0;
 662         cinfo.comp_info[0].v_samp_factor = img->samp_v0;
 663         if (img->num_components == 3) {
 664                 cinfo.comp_info[1].h_samp_factor = img->samp_h1;
 665                 cinfo.comp_info[1].v_samp_factor = img->samp_v1;
 666                 cinfo.comp_info[2].h_samp_factor = img->samp_h2;
 667                 cinfo.comp_info[2].v_samp_factor = img->samp_v2;
 668         }
 669         jpeg_start_compress(&cinfo, TRUE);
 670
 671         unsigned dstride0 = (img->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 672         unsigned dstride1 = (img->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 673         unsigned dstride2 = (img->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 674
 675         int total_lines = 0;
 676         int blocks = 0;
 677         while (total_lines < cinfo.comp_info[0].height_in_blocks * DCTSIZE) {
 678                 unsigned max_lines = cinfo.max_v_samp_factor * DCTSIZE;
 679
 680                 JSAMPROW y_row_ptrs[max_lines];
 681                 JSAMPROW cb_row_ptrs[max_lines];
 682                 JSAMPROW cr_row_ptrs[max_lines];
 683                 JSAMPROW* ptrs[] = { y_row_ptrs, cb_row_ptrs, cr_row_ptrs };
 684                 int i;
 685
 686                 for (i = 0; i < max_lines; ++i) {
 687                         /* simple edge extension */
 688                         int yline = i + blocks*DCTSIZE*cinfo.comp_info[0].v_samp_factor;
 689                         if (yline > img->h0 - 1)
 690                                 yline = img->h0 - 1;
 691
 692                         y_row_ptrs[i]  = img->data_y  + yline * dstride0;
 693
 694                         if (img->num_components == 3) {
 695                                 int cbline = i + blocks*DCTSIZE*cinfo.comp_info[1].v_samp_factor;
 696                                 if (cbline > img->h1 - 1)
 697                                         cbline = img->h1 - 1;
 698
 699                                 int crline = i + blocks*DCTSIZE*cinfo.comp_info[2].v_samp_factor;
 700                                 if (crline > img->h2 - 1)
 701                                         crline = img->h2 - 1;
 702
 703                                 cb_row_ptrs[i] = img->data_cb + cbline * dstride1;
 704                                 cr_row_ptrs[i] = img->data_cr + crline * dstride2;
 705                         }
 706                 }
 707
 708                 total_lines += max_lines;
 709                 ++blocks;
 710
 711                 jpeg_write_raw_data(&cinfo, ptrs, max_lines);
 712         }
 713         jpeg_finish_compress(&cinfo);
 714         jpeg_destroy_compress(&cinfo);
 715
 716         return 0;
 717 }