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 qscale_img *qscale_load_jpeg(const char *filename)
  46 {
  47         FILE *file = fopen(filename, "rb");
  48         qscale_img *img;
  49         if (file == NULL) {
  50                 return NULL;
  51         }
  52
  53         img = qscale_load_jpeg_from_stdio(file);
  54
  55         fclose(file);
  56         return img;
  57 }
  58
  59 qscale_img *qscale_load_jpeg_from_stdio(FILE *file)
  60 {
  61         qscale_img *img = (qscale_img *)malloc(sizeof(qscale_img));
  62         if (img == NULL) {
  63                 return NULL;
  64         }
  65
  66         img->data_y = img->data_cb = img->data_cr = NULL;
  67
  68         /* FIXME: Better error handling here (ie., return NULL). */
  69         struct jpeg_decompress_struct dinfo;
  70         struct jpeg_error_mgr jerr;
  71         dinfo.err = jpeg_std_error(&jerr);
  72         jpeg_create_decompress(&dinfo);
  73         jpeg_stdio_src(&dinfo, file);
  74         jpeg_read_header(&dinfo, TRUE);
  75         dinfo.raw_data_out = TRUE;
  76         jpeg_start_decompress(&dinfo);
  77
  78         if (dinfo.num_components != 1 && dinfo.num_components != 3) {
  79                 qscale_destroy(img);
  80                 return NULL;
  81         }
  82         img->num_components = dinfo.num_components;
  83
  84         img->width = dinfo.image_width;
  85         img->height = dinfo.image_height;
  86
  87         img->w0 = dinfo.image_width * dinfo.comp_info[0].h_samp_factor / dinfo.max_h_samp_factor;
  88         img->h0 = dinfo.image_height * dinfo.comp_info[0].v_samp_factor / dinfo.max_v_samp_factor;
  89
  90         if (img->num_components == 3) {
  91                 img->w1 = dinfo.image_width * dinfo.comp_info[1].h_samp_factor / dinfo.max_h_samp_factor;
  92                 img->h1 = dinfo.image_height * dinfo.comp_info[1].v_samp_factor / dinfo.max_v_samp_factor;
  93
  94                 img->w2 = dinfo.image_width * dinfo.comp_info[2].h_samp_factor / dinfo.max_h_samp_factor;
  95                 img->h2 = dinfo.image_height * dinfo.comp_info[2].v_samp_factor / dinfo.max_v_samp_factor;
  96         }
  97
  98         img->samp_h0 = dinfo.comp_info[0].h_samp_factor;
  99         img->samp_v0 = dinfo.comp_info[0].v_samp_factor;
 100
 101         if (img->num_components == 3) {
 102                 img->samp_h1 = dinfo.comp_info[1].h_samp_factor;
 103                 img->samp_v1 = dinfo.comp_info[1].v_samp_factor;
 104
 105                 img->samp_h2 = dinfo.comp_info[2].h_samp_factor;
 106                 img->samp_v2 = dinfo.comp_info[2].v_samp_factor;
 107         }
 108
 109         img->data_y  = (JSAMPLE*)memalign(16, dinfo.comp_info[0].height_in_blocks * dinfo.comp_info[0].width_in_blocks * DCTSIZE * DCTSIZE);
 110         if (img->data_y == NULL) {
 111                 qscale_destroy(img);
 112                 return NULL;
 113         }
 114
 115         if (img->num_components == 3) {
 116                 img->data_cb = (JSAMPLE*)memalign(16, dinfo.comp_info[1].height_in_blocks * dinfo.comp_info[1].width_in_blocks * DCTSIZE * DCTSIZE);
 117                 img->data_cr = (JSAMPLE*)memalign(16, dinfo.comp_info[2].height_in_blocks * dinfo.comp_info[2].width_in_blocks * DCTSIZE * DCTSIZE);
 118                 if (img->data_cb == NULL || img->data_cr == NULL) {
 119                         qscale_destroy(img);
 120                         return NULL;
 121                 }
 122         }
 123
 124         int total_lines = 0, blocks = 0;
 125         while (total_lines < dinfo.comp_info[0].height_in_blocks * DCTSIZE) {
 126                 unsigned max_lines = dinfo.max_v_samp_factor * DCTSIZE;
 127
 128                 JSAMPROW y_row_ptrs[max_lines];
 129                 JSAMPROW cb_row_ptrs[max_lines];
 130                 JSAMPROW cr_row_ptrs[max_lines];
 131                 JSAMPROW* ptrs[] = { y_row_ptrs, cb_row_ptrs, cr_row_ptrs };
 132
 133                 int i;
 134                 for (i = 0; i < max_lines; ++i) {
 135                         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;
 136                         if (img->num_components == 3) {
 137                                 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;
 138                                 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;
 139                         }
 140                 }
 141
 142                 total_lines += max_lines;
 143                 ++blocks;
 144
 145                 if (jpeg_read_raw_data(&dinfo, ptrs, max_lines) == 0)
 146                         break;
 147         }
 148
 149         jpeg_destroy_decompress(&dinfo);
 150         return img;
 151 }
 152
 153 void qscale_destroy(qscale_img *img)
 154 {
 155         free(img->data_y);
 156         free(img->data_cb);
 157         free(img->data_cr);
 158         free(img);
 159 }
 160
 161
 162 static double sinc(double x)
 163 {
 164         static const double cutoff = 1.220703668e-4;  /* sqrt(sqrt(eps)) */
 165
 166         if (abs(x) < cutoff) {
 167                 /* For small |x|, use Taylor series instead */
 168                 const double x2 = x * x;
 169                 const double x4 = x2 * x2;
 170
 171                 return 1.0 - x2 / 6.0 + x4 / 120.0;
 172         } else {
 173                 return sin(x) / x;
 174         }
 175 }
 176
 177 static double lanczos_tap(double x)
 178 {
 179         if (x < -3.0 || x > 3.0)
 180                 return 0.0;
 181         if (x < 0.0)
 182                 return sinc(-x*M_PI) * sinc(-x*M_PI / 3.0);
 183         else
 184                 return sinc(x*M_PI) * sinc(x*M_PI / 3.0);
 185 }
 186
 187 static double mitchell_tap(double x)
 188 {
 189         const double b = 1.0 / 3.0;
 190         const double c = 1.0 / 3.0;
 191         const double p0 = (  6.0 -  2.0*b         ) / 6.0;
 192         const double p2 = (-18.0 + 12.0*b +  6.0*c) / 6.0;
 193         const double p3 = ( 12.0 -  9.0*b -  6.0*c) / 6.0;
 194         const double q0 = (         8.0*b + 24.0*c) / 6.0;
 195         const double q1 = (      - 12.0*b - 48.0*c) / 6.0;
 196         const double q2 = (         6.0*b + 30.0*c) / 6.0;
 197         const double q3 = (      -      b -  6.0*c) / 6.0;
 198
 199         if (x < -2.0) {
 200                 return 0.0;
 201         } else if (x < -1.0) {
 202                 return q0 - x * (q1 - x * (q2 - x * q3));
 203         } else if (x < 0.0) {
 204                 return p0 + x * x * (p2 - x * p3);
 205         } else if (x < 1.0) {
 206                 return p0 + x * x * (p2 + x * p3);
 207         } else if (x < 2.0) {
 208                 return q0 + x * (q1 + x * (q2 + x * q3));
 209         } else {
 210                 return 0.0;
 211         }
 212 }
 213
 214 struct pix_desc {
 215         unsigned start, end;
 216         unsigned startcoeff;
 217 };
 218
 219 static void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw, unsigned sstride, unsigned dstride, enum qscale_scaling_filter scaling_filter)
 220 {
 221         struct pix_desc *pd = (struct pix_desc *)malloc(nw * sizeof(struct pix_desc));
 222         int size_coeffs = 8;
 223         float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
 224         int num_coeffs = 0;
 225         int x, y;
 226         double sf = (double)w / (double)nw;
 227         double support;
 228
 229         if (scaling_filter == LANCZOS) {
 230                 support = (w > nw) ? (3.0 * sf) : (3.0 / sf);
 231         } else {  /* Mitchell */
 232                 support = (w > nw) ? (2.0 * sf) : (2.0 / sf);
 233         }
 234
 235         /* calculate the filter */
 236         for (x = 0; x < nw; ++x) {
 237                 int start = ceil(x * sf - support);
 238                 int end = floor(x * sf + support);
 239                 int sx;
 240                 double sum = 0.0;
 241
 242                 if (start < 0) {
 243                         start = 0;
 244                 }
 245                 if (end > w - 1) {
 246                         end = w - 1;
 247                 }
 248
 249 #if USE_HORIZONTAL_SSE
 250                 /* round up so we get a multiple of four for the SSE code */
 251                 int num = (end - start + 1);
 252                 if (num % 4 != 0) {
 253                         /* prefer aligning it if possible */
 254                         if (start % 4 != 0 && start % 4 <= num % 4) {
 255                                 num += start % 4;
 256                                 start -= start % 4;
 257                         }
 258                         if (num % 4 != 0) {
 259                                 end += 4 - (num % 4);
 260                         }
 261                 }
 262 #endif
 263
 264                 pd[x].start = start;
 265                 pd[x].end = end;
 266                 pd[x].startcoeff = num_coeffs;
 267
 268                 for (sx = start; sx <= end; ++sx) {
 269                         double nd = (w > nw) ? (sx/sf - x) : (sx - x*sf);
 270                         double f;
 271                         if (scaling_filter == LANCZOS) {
 272                                 f = lanczos_tap(nd);
 273                         } else {  /* Mitchell */
 274                                 f = mitchell_tap(nd);
 275                         }
 276                         if (num_coeffs == size_coeffs) {
 277                                 size_coeffs <<= 1;
 278                                 coeffs = (float *)realloc(coeffs, size_coeffs * sizeof(float));
 279                         }
 280
 281                         coeffs[num_coeffs++] = f;
 282                         sum += f;
 283                 }
 284
 285                 for (sx = start; sx <= end; ++sx) {
 286                         coeffs[pd[x].startcoeff + sx - start] /= sum;
 287                 }
 288         }
 289
 290         for (y = 0; y < h; ++y) {
 291                 float *sptr = pix + y*sstride;
 292                 unsigned char *dptr = npix + y*dstride;
 293                 unsigned char ch;
 294                 for (x = 0; x < nw; ++x) {
 295 #if USE_HORIZONTAL_SSE
 296                         int result;
 297                         float acc;
 298                         long tmp;
 299                         static const float low = 0.0, high = 255.0;
 300                         __asm__ (
 301                                 "pxor %1, %1               \n"
 302                                 "xor %2, %2                \n"
 303                                 "0:                        \n"
 304                                 "movups (%4,%2),%%xmm1     \n"
 305                                 "movups (%3,%2),%%xmm2     \n"
 306                                 "mulps %%xmm2,%%xmm1       \n"
 307                                 "addps %%xmm1,%1           \n"
 308                                 "add $16,%2                \n"
 309                                 "dec %5                    \n"
 310                                 "jnz 0b                    \n"
 311                                 "haddps %1,%1              \n"
 312                                 "haddps %1,%1              \n"
 313                                 "maxss %6,%1               \n"
 314                                 "minss %7,%1               \n"
 315                                 "cvtss2si %1,%0            \n"
 316                                 : "=r" (result),
 317                                   "=&x" (acc),
 318                                   "=&r" (tmp)
 319                                 : "r" (&coeffs[pd[x].startcoeff]),
 320                                   "r" (&sptr[pd[x].start]),
 321                                   "r" ((pd[x].end - pd[x].start + 1)/4),
 322                                   "m" (low),
 323                                   "m" (high)
 324                                 : "memory", "xmm1", "xmm2"
 325                         );
 326
 327                         *dptr++ = (unsigned char)result;
 328 #else
 329                         float acc = 0.0;
 330                         float *cf = &coeffs[pd[x].startcoeff];
 331                         unsigned sx;
 332
 333                         for (sx = pd[x].start; sx <= pd[x].end; ++sx) {
 334                                 acc += sptr[sx] * *cf++;
 335                         }
 336
 337                         if (acc < 0.0)
 338                                 ch = 0;
 339                         else if (acc > 255.0)
 340                                 ch = 255;
 341                         else
 342                                 ch = (unsigned char)acc;
 343                         *dptr++ = ch;
 344 #endif
 345                 }
 346                 ch = dptr[-1];
 347                 for ( ; x < dstride; ++x) {
 348                         *dptr++ = ch;
 349                 }
 350         }
 351 }
 352
 353 static void vscale(unsigned char *pix, float *npix, unsigned w, unsigned h, unsigned nh, unsigned dstride, enum qscale_scaling_filter scaling_filter)
 354 {
 355         struct pix_desc *pd = (struct pix_desc *)malloc(nh * sizeof(struct pix_desc));
 356         int size_coeffs = 8;
 357         float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
 358         int num_coeffs = 0;
 359         int x, y, sy;
 360         double sf = (double)h / (double)nh;
 361         double support;
 362
 363         if (scaling_filter == LANCZOS) {
 364                 support = (h > nh) ? (3.0 * sf) : (3.0 / sf);
 365         } else {  /* Mitchell */
 366                 support = (h > nh) ? (2.0 * sf) : (2.0 / sf);
 367         }
 368
 369         /* calculate the filter */
 370         for (y = 0; y < nh; ++y) {
 371                 int start = ceil(y * sf - support);
 372                 int end = floor(y * sf + support);
 373                 double sum = 0.0;
 374
 375                 if (start < 0) {
 376                         start = 0;
 377                 }
 378                 if (end > h - 1) {
 379                         end = h - 1;
 380                 }
 381
 382                 pd[y].start = start;
 383                 pd[y].end = end;
 384                 pd[y].startcoeff = num_coeffs;
 385
 386                 for (sy = start; sy <= end; ++sy) {
 387                         double nd = (h > nh) ? (sy/sf - y) : (sy - y*sf);
 388                         double f;
 389                         if (scaling_filter == LANCZOS) {
 390                                 f = lanczos_tap(nd);
 391                         } else {  /* Mitchell */
 392                                 f = mitchell_tap(nd);
 393                         }
 394                         if (num_coeffs == size_coeffs) {
 395                                 size_coeffs <<= 1;
 396                                 coeffs = (float *)realloc(coeffs, size_coeffs * sizeof(float));
 397                         }
 398
 399                         coeffs[num_coeffs++] = f;
 400                         sum += f;
 401                 }
 402
 403                 for (sy = start; sy <= end; ++sy) {
 404                         coeffs[pd[y].startcoeff + sy - start] /= sum;
 405                 }
 406         }
 407
 408 #if CACHE_LINE_FACTOR > 1
 409         for (x = 0; x < (w/CACHE_LINE_FACTOR) * CACHE_LINE_FACTOR; x += CACHE_LINE_FACTOR) {
 410                 unsigned char *sptr = pix + x;
 411                 float *dptr = npix + x;
 412                 for (y = 0; y < nh; ++y) {
 413 #if USE_VERTICAL_SSE
 414                         /*
 415                          * xmm0 - xmm3: acc[0..15]
 416                          * xmm4: current filter coefficient
 417                          * xmm5, xmm6, xmm7: scratchpad
 418                          */
 419                         __asm__ (
 420                                 /* clear */
 421                                 "pxor %%xmm0, %%xmm0          \n"
 422                                 "pxor %%xmm1, %%xmm1          \n"
 423                                 "pxor %%xmm2, %%xmm2          \n"
 424                                 "pxor %%xmm3, %%xmm3          \n"
 425
 426                                 /* main loop */
 427                                 "0:                           \n"
 428
 429                                 /* a zero is useful during unpacking */
 430                                 "pxor %%xmm4, %%xmm4          \n"
 431
 432                                 /* fetch all 16 source bytes */
 433                                 "movups (%0), %%xmm5          \n"
 434                                 "prefetcht0 (%0,%3,4)         \n"
 435
 436                                 /* unpack into words (xmm5, xmm7) */
 437                                 "movaps %%xmm5, %%xmm7        \n"
 438                                 "punpcklbw %%xmm4, %%xmm5     \n"
 439                                 "punpckhbw %%xmm4, %%xmm7     \n"
 440
 441                                 /* unpack xmm5 into dwords (xmm5, xmm6) */
 442                                 "movaps %%xmm5, %%xmm6        \n"
 443                                 "punpcklwd %%xmm4, %%xmm5     \n"
 444                                 "punpckhwd %%xmm4, %%xmm6     \n"
 445
 446                                 /* convert xmm5, xmm6 to floats */
 447                                 "cvtdq2ps %%xmm5, %%xmm5      \n"
 448                                 "cvtdq2ps %%xmm6, %%xmm6      \n"
 449
 450                                 /* fetch the coefficient */
 451                                 "movss (%2), %%xmm4           \n"
 452                                 "shufps $0x0, %%xmm4, %%xmm4  \n"
 453
 454                                 /* do the muls for xmm5 and xmm6 */
 455                                 "mulps %%xmm4, %%xmm5         \n"
 456                                 "mulps %%xmm4, %%xmm6         \n"
 457                                 "addps %%xmm5, %%xmm0         \n"
 458                                 "addps %%xmm6, %%xmm1         \n"
 459
 460                                 /* get the zero back again */
 461                                 "pxor %%xmm4, %%xmm4          \n"
 462
 463                                 /* unpack xmm7 into dwords (xmm7, xmm6) */
 464                                 "movaps %%xmm7, %%xmm6        \n"
 465                                 "punpcklwd %%xmm4, %%xmm7     \n"
 466                                 "punpckhwd %%xmm4, %%xmm6     \n"
 467
 468                                 /* convert xmm7, xmm6 to floats */
 469                                 "cvtdq2ps %%xmm7, %%xmm7      \n"
 470                                 "cvtdq2ps %%xmm6, %%xmm6      \n"
 471
 472                                 /* fetch the coefficient */
 473                                 "movss (%2), %%xmm4           \n"
 474                                 "shufps $0x0, %%xmm4, %%xmm4  \n"
 475
 476                                 /* do the second set of muls */
 477                                 "mulps %%xmm4, %%xmm7         \n"
 478                                 "mulps %%xmm4, %%xmm6         \n"
 479                                 "addps %%xmm7, %%xmm2         \n"
 480                                 "addps %%xmm6, %%xmm3         \n"
 481
 482                                 /* move along, and loop */
 483                                 "add $4, %2                   \n"
 484                                 "add %3, %0                   \n"
 485                                 "dec %1                       \n"
 486                                 "jnz 0b                       \n"
 487
 488                                 /* store the values */
 489                                 "movaps %%xmm0, (%4)          \n"
 490                                 "movaps %%xmm1, 16(%4)        \n"
 491                                 "movaps %%xmm2, 32(%4)        \n"
 492                                 "movaps %%xmm3, 48(%4)        \n"
 493                                 : :
 494                                 "r" (&sptr[pd[y].start * w]),        /* 0: srcptr base */
 495                                 "r" (pd[y].end - pd[y].start + 1),   /* 1: filter len */
 496                                 "r" (&coeffs[pd[y].startcoeff]),     /* 2: coeffs base */
 497                                 "r" ((long)w),                       /* 3: stride */
 498                                 "r" (dptr)                           /* 4: dstptr base */
 499                                 : "memory", "xmm0", "xmm1", "xmm2", "xmm3", "xmm4", "xmm5", "xmm6", "xmm7"
 500                         );
 501 #else
 502                         int i;
 503                         float acc[CACHE_LINE_FACTOR];
 504                         for (i = 0; i < CACHE_LINE_FACTOR; ++i)
 505                                 acc[i] = 0.0;
 506                         float *cf = &coeffs[pd[y].startcoeff];
 507                         unsigned sy;
 508
 509                         for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
 510                                 for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
 511                                         acc[i] += sptr[sy * w + i] * *cf;
 512                                 }
 513                                 ++cf;
 514                         }
 515
 516                         for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
 517                                 dptr[i] = acc[i];
 518                         }
 519 #endif
 520                         dptr += dstride;
 521                 }
 522         }
 523         for (x = (x/CACHE_LINE_FACTOR)*CACHE_LINE_FACTOR; x < w; ++x) {
 524 #else
 525         for (x = 0; x < w; ++x) {
 526 #endif
 527                 unsigned char *sptr = pix + x;
 528                 float *dptr = npix + x;
 529                 for (y = 0; y < nh; ++y) {
 530                         float acc = 0.0;
 531                         float *cf = &coeffs[pd[y].startcoeff];
 532                         unsigned sy;
 533
 534                         for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
 535                                 acc += sptr[sy * w] * *cf++;
 536                         }
 537
 538                         *dptr = acc;
 539                         dptr += dstride;
 540                 }
 541         }
 542 }
 543
 544 qscale_img *qscale_clone(const qscale_img *img)
 545 {
 546         qscale_img *dst = (qscale_img *)malloc(sizeof(qscale_img));
 547         if (dst == NULL) {
 548                 return NULL;
 549         }
 550
 551         *dst = *img;
 552
 553         unsigned dstride0 = (dst->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 554         unsigned dstride1 = (dst->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 555         unsigned dstride2 = (dst->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 556
 557         /* FIXME: handle out-of-memory gracefully */
 558         {
 559                 dst->data_y = (unsigned char *)malloc(dst->h0 * dstride0);
 560                 memcpy(dst->data_y, img->data_y, dst->h0 * dstride0);
 561         }
 562         {
 563                 dst->data_cb = (unsigned char *)malloc(dst->h1 * dstride1);
 564                 memcpy(dst->data_cb, img->data_cb, dst->h1 * dstride1);
 565         }
 566         {
 567                 dst->data_cr = (unsigned char *)malloc(dst->h2 * dstride2);
 568                 memcpy(dst->data_cr, img->data_cr, dst->h2 * dstride2);
 569         }
 570
 571         return dst;
 572 }
 573
 574 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)
 575 {
 576         qscale_img *dst = (qscale_img *)malloc(sizeof(qscale_img));
 577         if (dst == NULL) {
 578                 return NULL;
 579         }
 580
 581         dst->width = width;
 582         dst->height = height;
 583         dst->num_components = src->num_components;
 584
 585         unsigned max_samp_h, max_samp_v;
 586         max_samp_h = samp_h0;
 587         if (src->num_components == 3) {
 588                 if (samp_h1 > max_samp_h)
 589                         max_samp_h = samp_h1;
 590                 if (samp_h2 > max_samp_h)
 591                         max_samp_h = samp_h2;
 592         }
 593
 594         max_samp_v = samp_v0;
 595         if (src->num_components == 3) {
 596                 if (samp_v1 > max_samp_v)
 597                         max_samp_v = samp_v1;
 598                 if (samp_v2 > max_samp_v)
 599                         max_samp_v = samp_v2;
 600         }
 601
 602         dst->w0 = width * samp_h0 / max_samp_h;
 603         dst->h0 = height * samp_v0 / max_samp_v;
 604
 605         if (src->num_components == 3) {
 606                 dst->w1 = width * samp_h1 / max_samp_h;
 607                 dst->h1 = height * samp_v1 / max_samp_v;
 608
 609                 dst->w2 = width * samp_h2 / max_samp_h;
 610                 dst->h2 = height * samp_v2 / max_samp_v;
 611         }
 612
 613         dst->samp_h0 = samp_h0;
 614         dst->samp_v0 = samp_v0;
 615
 616         if (src->num_components == 3) {
 617                 dst->samp_h1 = samp_h1;
 618                 dst->samp_v1 = samp_v1;
 619
 620                 dst->samp_h2 = samp_h2;
 621                 dst->samp_v2 = samp_v2;
 622         }
 623
 624         unsigned dstride0 = (dst->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 625         unsigned dstride1 = (dst->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 626         unsigned dstride2 = (dst->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 627
 628         unsigned sstride0 = (src->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 629         unsigned sstride1 = (src->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 630         unsigned sstride2 = (src->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 631
 632         /* FIXME: handle out-of-memory gracefully */
 633         {
 634                 float *npix = (float*)memalign(16, sstride0 * dst->h0 * sizeof(float));
 635                 vscale(src->data_y, npix, sstride0, src->h0, dst->h0, sstride0, scaling_filter);
 636                 dst->data_y = (unsigned char *)malloc(dst->h0 * dstride0);
 637                 hscale(npix, dst->data_y, src->w0, dst->h0, dst->w0, sstride0, dstride0, scaling_filter);
 638                 free(npix);
 639         }
 640         if (src->num_components == 3) {
 641                 {
 642                         float *npix = (float*)memalign(16, sstride1 * dst->h1 * sizeof(float));
 643                         vscale(src->data_cr, npix, sstride1, src->h1, dst->h1, sstride1, scaling_filter);
 644                         dst->data_cr = (unsigned char *)malloc(dst->h1 * dstride1);
 645                         hscale(npix, dst->data_cr, src->w1, dst->h1, dst->w1, sstride1, dstride1, scaling_filter);
 646                         free(npix);
 647                 }
 648                 {
 649                         float *npix = (float*)memalign(16, sstride2 * dst->h2 * sizeof(float));
 650                         vscale(src->data_cb, npix, sstride2, src->h2, dst->h2, sstride2, scaling_filter);
 651                         dst->data_cb = (unsigned char *)malloc(dst->h2 * dstride2);
 652                         hscale(npix, dst->data_cb, src->w2, dst->h2, dst->w2, sstride2, dstride2, scaling_filter);
 653                         free(npix);
 654                 }
 655         }
 656
 657         return dst;
 658 }
 659
 660 int qscale_save_jpeg(const qscale_img *img, const char *filename, unsigned jpeg_quality, enum qscale_jpeg_mode jpeg_mode)
 661 {
 662         FILE *file = fopen(filename, "wb");
 663         if (file == NULL) {
 664                 return -1;
 665         }
 666
 667         int err = qscale_save_jpeg_to_stdio(img, file, jpeg_quality, jpeg_mode);
 668
 669         fclose(file);
 670         return err;
 671 }
 672
 673 int qscale_save_jpeg_to_stdio(const qscale_img *img, FILE *file, unsigned jpeg_quality, enum qscale_jpeg_mode jpeg_mode)
 674 {
 675         struct jpeg_compress_struct cinfo;
 676         struct jpeg_error_mgr jerr;
 677         cinfo.err = jpeg_std_error(&jerr);
 678         jpeg_create_compress(&cinfo);
 679         jpeg_stdio_dest(&cinfo, file);
 680         cinfo.input_components = img->num_components;
 681         jpeg_set_defaults(&cinfo);
 682         jpeg_set_quality(&cinfo, jpeg_quality, FALSE);
 683
 684         if (jpeg_mode == PROGRESSIVE) {
 685                 jpeg_simple_progression(&cinfo);
 686         }
 687
 688         cinfo.image_width = img->width;
 689         cinfo.image_height = img->height;
 690         cinfo.raw_data_in = TRUE;
 691         if (img->num_components == 3) {
 692                 jpeg_set_colorspace(&cinfo, JCS_YCbCr);
 693         } else {
 694                 jpeg_set_colorspace(&cinfo, JCS_GRAYSCALE);
 695         }
 696         cinfo.comp_info[0].h_samp_factor = img->samp_h0;
 697         cinfo.comp_info[0].v_samp_factor = img->samp_v0;
 698         if (img->num_components == 3) {
 699                 cinfo.comp_info[1].h_samp_factor = img->samp_h1;
 700                 cinfo.comp_info[1].v_samp_factor = img->samp_v1;
 701                 cinfo.comp_info[2].h_samp_factor = img->samp_h2;
 702                 cinfo.comp_info[2].v_samp_factor = img->samp_v2;
 703         }
 704         jpeg_start_compress(&cinfo, TRUE);
 705
 706         unsigned dstride0 = (img->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
 707         unsigned dstride1 = (img->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
 708         unsigned dstride2 = (img->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
 709
 710         int total_lines = 0;
 711         int blocks = 0;
 712         while (total_lines < cinfo.comp_info[0].height_in_blocks * DCTSIZE) {
 713                 unsigned max_lines = cinfo.max_v_samp_factor * DCTSIZE;
 714
 715                 JSAMPROW y_row_ptrs[max_lines];
 716                 JSAMPROW cb_row_ptrs[max_lines];
 717                 JSAMPROW cr_row_ptrs[max_lines];
 718                 JSAMPROW* ptrs[] = { y_row_ptrs, cb_row_ptrs, cr_row_ptrs };
 719                 int i;
 720
 721                 for (i = 0; i < max_lines; ++i) {
 722                         /* simple edge extension */
 723                         int yline = i + blocks*DCTSIZE*cinfo.comp_info[0].v_samp_factor;
 724                         if (yline > img->h0 - 1)
 725                                 yline = img->h0 - 1;
 726
 727                         y_row_ptrs[i]  = img->data_y  + yline * dstride0;
 728
 729                         if (img->num_components == 3) {
 730                                 int cbline = i + blocks*DCTSIZE*cinfo.comp_info[1].v_samp_factor;
 731                                 if (cbline > img->h1 - 1)
 732                                         cbline = img->h1 - 1;
 733
 734                                 int crline = i + blocks*DCTSIZE*cinfo.comp_info[2].v_samp_factor;
 735                                 if (crline > img->h2 - 1)
 736                                         crline = img->h2 - 1;
 737
 738                                 cb_row_ptrs[i] = img->data_cb + cbline * dstride1;
 739                                 cr_row_ptrs[i] = img->data_cr + crline * dstride2;
 740                         }
 741                 }
 742
 743                 total_lines += max_lines;
 744                 ++blocks;
 745
 746                 jpeg_write_raw_data(&cinfo, ptrs, max_lines);
 747         }
 748         jpeg_finish_compress(&cinfo);
 749         jpeg_destroy_compress(&cinfo);
 750
 751         return 0;
 752 }