stb_image_write.h 59 KB

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  1. /* stb_image_write - v1.07 - public domain - http://nothings.org/stb/stb_image_write.h
  2. writes out PNG/BMP/TGA/JPEG/HDR images to C stdio - Sean Barrett 2010-2015
  3. no warranty implied; use at your own risk
  4. Before #including,
  5. #define STB_IMAGE_WRITE_IMPLEMENTATION
  6. in the file that you want to have the implementation.
  7. Will probably not work correctly with strict-aliasing optimizations.
  8. ABOUT:
  9. This header file is a library for writing images to C stdio. It could be
  10. adapted to write to memory or a general streaming interface; let me know.
  11. The PNG output is not optimal; it is 20-50% larger than the file
  12. written by a decent optimizing implementation. This library is designed
  13. for source code compactness and simplicity, not optimal image file size
  14. or run-time performance.
  15. BUILDING:
  16. You can #define STBIW_ASSERT(x) before the #include to avoid using assert.h.
  17. You can #define STBIW_MALLOC(), STBIW_REALLOC(), and STBIW_FREE() to replace
  18. malloc,realloc,free.
  19. You can define STBIW_MEMMOVE() to replace memmove()
  20. USAGE:
  21. There are four functions, one for each image file format:
  22. int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
  23. int stbi_write_bmp(char const *filename, int w, int h, int comp, const void *data);
  24. int stbi_write_tga(char const *filename, int w, int h, int comp, const void *data);
  25. int stbi_write_hdr(char const *filename, int w, int h, int comp, const float *data);
  26. int stbi_write_jpg(char const *filename, int w, int h, int comp, const float *data);
  27. There are also four equivalent functions that use an arbitrary write function. You are
  28. expected to open/close your file-equivalent before and after calling these:
  29. int stbi_write_png_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data, int stride_in_bytes);
  30. int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
  31. int stbi_write_tga_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
  32. int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const float *data);
  33. int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality);
  34. where the callback is:
  35. void stbi_write_func(void *context, void *data, int size);
  36. You can define STBI_WRITE_NO_STDIO to disable the file variant of these
  37. functions, so the library will not use stdio.h at all. However, this will
  38. also disable HDR writing, because it requires stdio for formatted output.
  39. Each function returns 0 on failure and non-0 on success.
  40. The functions create an image file defined by the parameters. The image
  41. is a rectangle of pixels stored from left-to-right, top-to-bottom.
  42. Each pixel contains 'comp' channels of data stored interleaved with 8-bits
  43. per channel, in the following order: 1=Y, 2=YA, 3=RGB, 4=RGBA. (Y is
  44. monochrome color.) The rectangle is 'w' pixels wide and 'h' pixels tall.
  45. The *data pointer points to the first byte of the top-left-most pixel.
  46. For PNG, "stride_in_bytes" is the distance in bytes from the first byte of
  47. a row of pixels to the first byte of the next row of pixels.
  48. PNG creates output files with the same number of components as the input.
  49. The BMP format expands Y to RGB in the file format and does not
  50. output alpha.
  51. PNG supports writing rectangles of data even when the bytes storing rows of
  52. data are not consecutive in memory (e.g. sub-rectangles of a larger image),
  53. by supplying the stride between the beginning of adjacent rows. The other
  54. formats do not. (Thus you cannot write a native-format BMP through the BMP
  55. writer, both because it is in BGR order and because it may have padding
  56. at the end of the line.)
  57. HDR expects linear float data. Since the format is always 32-bit rgb(e)
  58. data, alpha (if provided) is discarded, and for monochrome data it is
  59. replicated across all three channels.
  60. TGA supports RLE or non-RLE compressed data. To use non-RLE-compressed
  61. data, set the global variable 'stbi_write_tga_with_rle' to 0.
  62. JPEG does ignore alpha channels in input data; quality is between 1 and 100.
  63. Higher quality looks better but results in a bigger image.
  64. JPEG baseline (no JPEG progressive).
  65. CREDITS:
  66. PNG/BMP/TGA
  67. Sean Barrett
  68. HDR
  69. Baldur Karlsson
  70. TGA monochrome:
  71. Jean-Sebastien Guay
  72. misc enhancements:
  73. Tim Kelsey
  74. TGA RLE
  75. Alan Hickman
  76. initial file IO callback implementation
  77. Emmanuel Julien
  78. JPEG
  79. Jon Olick (original jo_jpeg.cpp code)
  80. Daniel Gibson
  81. bugfixes:
  82. github:Chribba
  83. Guillaume Chereau
  84. github:jry2
  85. github:romigrou
  86. Sergio Gonzalez
  87. Jonas Karlsson
  88. Filip Wasil
  89. Thatcher Ulrich
  90. github:poppolopoppo
  91. Patrick Boettcher
  92. LICENSE
  93. See end of file for license information.
  94. */
  95. #ifndef INCLUDE_STB_IMAGE_WRITE_H
  96. #define INCLUDE_STB_IMAGE_WRITE_H
  97. #ifdef __cplusplus
  98. extern "C" {
  99. #endif
  100. #ifdef STB_IMAGE_WRITE_STATIC
  101. #define STBIWDEF static
  102. #else
  103. #define STBIWDEF extern
  104. extern int stbi_write_tga_with_rle;
  105. #endif
  106. #ifndef STBI_WRITE_NO_STDIO
  107. STBIWDEF int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
  108. STBIWDEF int stbi_write_bmp(char const *filename, int w, int h, int comp, const void *data);
  109. STBIWDEF int stbi_write_tga(char const *filename, int w, int h, int comp, const void *data);
  110. STBIWDEF int stbi_write_hdr(char const *filename, int w, int h, int comp, const float *data);
  111. STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const void *data, int quality);
  112. #endif
  113. typedef void stbi_write_func(void *context, void *data, int size);
  114. STBIWDEF int stbi_write_png_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data, int stride_in_bytes);
  115. STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
  116. STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
  117. STBIWDEF int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const float *data);
  118. STBIWDEF int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality);
  119. #ifdef __cplusplus
  120. }
  121. #endif
  122. #endif//INCLUDE_STB_IMAGE_WRITE_H
  123. #ifdef STB_IMAGE_WRITE_IMPLEMENTATION
  124. #ifdef _WIN32
  125. #ifndef _CRT_SECURE_NO_WARNINGS
  126. #define _CRT_SECURE_NO_WARNINGS
  127. #endif
  128. #ifndef _CRT_NONSTDC_NO_DEPRECATE
  129. #define _CRT_NONSTDC_NO_DEPRECATE
  130. #endif
  131. #endif
  132. #ifndef STBI_WRITE_NO_STDIO
  133. #include <stdio.h>
  134. #endif // STBI_WRITE_NO_STDIO
  135. #include <stdarg.h>
  136. #include <stdlib.h>
  137. #include <string.h>
  138. #include <math.h>
  139. #if defined(STBIW_MALLOC) && defined(STBIW_FREE) && (defined(STBIW_REALLOC) || defined(STBIW_REALLOC_SIZED))
  140. // ok
  141. #elif !defined(STBIW_MALLOC) && !defined(STBIW_FREE) && !defined(STBIW_REALLOC) && !defined(STBIW_REALLOC_SIZED)
  142. // ok
  143. #else
  144. #error "Must define all or none of STBIW_MALLOC, STBIW_FREE, and STBIW_REALLOC (or STBIW_REALLOC_SIZED)."
  145. #endif
  146. #ifndef STBIW_MALLOC
  147. #define STBIW_MALLOC(sz) malloc(sz)
  148. #define STBIW_REALLOC(p,newsz) realloc(p,newsz)
  149. #define STBIW_FREE(p) free(p)
  150. #endif
  151. #ifndef STBIW_REALLOC_SIZED
  152. #define STBIW_REALLOC_SIZED(p,oldsz,newsz) STBIW_REALLOC(p,newsz)
  153. #endif
  154. #ifndef STBIW_MEMMOVE
  155. #define STBIW_MEMMOVE(a,b,sz) memmove(a,b,sz)
  156. #endif
  157. #ifndef STBIW_ASSERT
  158. #include <assert.h>
  159. #define STBIW_ASSERT(x) assert(x)
  160. #endif
  161. #define STBIW_UCHAR(x) (unsigned char) ((x) & 0xff)
  162. typedef struct
  163. {
  164. stbi_write_func *func;
  165. void *context;
  166. } stbi__write_context;
  167. // initialize a callback-based context
  168. static void stbi__start_write_callbacks(stbi__write_context *s, stbi_write_func *c, void *context)
  169. {
  170. s->func = c;
  171. s->context = context;
  172. }
  173. #ifndef STBI_WRITE_NO_STDIO
  174. static void stbi__stdio_write(void *context, void *data, int size)
  175. {
  176. fwrite(data,1,size,(FILE*) context);
  177. }
  178. static int stbi__start_write_file(stbi__write_context *s, const char *filename)
  179. {
  180. FILE *f = fopen(filename, "wb");
  181. stbi__start_write_callbacks(s, stbi__stdio_write, (void *) f);
  182. return f != NULL;
  183. }
  184. static void stbi__end_write_file(stbi__write_context *s)
  185. {
  186. fclose((FILE *)s->context);
  187. }
  188. #endif // !STBI_WRITE_NO_STDIO
  189. typedef unsigned int stbiw_uint32;
  190. typedef int stb_image_write_test[sizeof(stbiw_uint32)==4 ? 1 : -1];
  191. #ifdef STB_IMAGE_WRITE_STATIC
  192. static int stbi_write_tga_with_rle = 1;
  193. #else
  194. int stbi_write_tga_with_rle = 1;
  195. #endif
  196. static void stbiw__writefv(stbi__write_context *s, const char *fmt, va_list v)
  197. {
  198. while (*fmt) {
  199. switch (*fmt++) {
  200. case ' ': break;
  201. case '1': { unsigned char x = STBIW_UCHAR(va_arg(v, int));
  202. s->func(s->context,&x,1);
  203. break; }
  204. case '2': { int x = va_arg(v,int);
  205. unsigned char b[2];
  206. b[0] = STBIW_UCHAR(x);
  207. b[1] = STBIW_UCHAR(x>>8);
  208. s->func(s->context,b,2);
  209. break; }
  210. case '4': { stbiw_uint32 x = va_arg(v,int);
  211. unsigned char b[4];
  212. b[0]=STBIW_UCHAR(x);
  213. b[1]=STBIW_UCHAR(x>>8);
  214. b[2]=STBIW_UCHAR(x>>16);
  215. b[3]=STBIW_UCHAR(x>>24);
  216. s->func(s->context,b,4);
  217. break; }
  218. default:
  219. STBIW_ASSERT(0);
  220. return;
  221. }
  222. }
  223. }
  224. static void stbiw__writef(stbi__write_context *s, const char *fmt, ...)
  225. {
  226. va_list v;
  227. va_start(v, fmt);
  228. stbiw__writefv(s, fmt, v);
  229. va_end(v);
  230. }
  231. static void stbiw__putc(stbi__write_context *s, unsigned char c)
  232. {
  233. s->func(s->context, &c, 1);
  234. }
  235. static void stbiw__write3(stbi__write_context *s, unsigned char a, unsigned char b, unsigned char c)
  236. {
  237. unsigned char arr[3];
  238. arr[0] = a, arr[1] = b, arr[2] = c;
  239. s->func(s->context, arr, 3);
  240. }
  241. static void stbiw__write_pixel(stbi__write_context *s, int rgb_dir, int comp, int write_alpha, int expand_mono, unsigned char *d)
  242. {
  243. unsigned char bg[3] = { 255, 0, 255}, px[3];
  244. int k;
  245. if (write_alpha < 0)
  246. s->func(s->context, &d[comp - 1], 1);
  247. switch (comp) {
  248. case 2: // 2 pixels = mono + alpha, alpha is written separately, so same as 1-channel case
  249. case 1:
  250. if (expand_mono)
  251. stbiw__write3(s, d[0], d[0], d[0]); // monochrome bmp
  252. else
  253. s->func(s->context, d, 1); // monochrome TGA
  254. break;
  255. case 4:
  256. if (!write_alpha) {
  257. // composite against pink background
  258. for (k = 0; k < 3; ++k)
  259. px[k] = bg[k] + ((d[k] - bg[k]) * d[3]) / 255;
  260. stbiw__write3(s, px[1 - rgb_dir], px[1], px[1 + rgb_dir]);
  261. break;
  262. }
  263. /* FALLTHROUGH */
  264. case 3:
  265. stbiw__write3(s, d[1 - rgb_dir], d[1], d[1 + rgb_dir]);
  266. break;
  267. }
  268. if (write_alpha > 0)
  269. s->func(s->context, &d[comp - 1], 1);
  270. }
  271. static void stbiw__write_pixels(stbi__write_context *s, int rgb_dir, int vdir, int x, int y, int comp, void *data, int write_alpha, int scanline_pad, int expand_mono)
  272. {
  273. stbiw_uint32 zero = 0;
  274. int i,j, j_end;
  275. if (y <= 0)
  276. return;
  277. if (vdir < 0)
  278. j_end = -1, j = y-1;
  279. else
  280. j_end = y, j = 0;
  281. for (; j != j_end; j += vdir) {
  282. for (i=0; i < x; ++i) {
  283. unsigned char *d = (unsigned char *) data + (j*x+i)*comp;
  284. stbiw__write_pixel(s, rgb_dir, comp, write_alpha, expand_mono, d);
  285. }
  286. s->func(s->context, &zero, scanline_pad);
  287. }
  288. }
  289. static int stbiw__outfile(stbi__write_context *s, int rgb_dir, int vdir, int x, int y, int comp, int expand_mono, void *data, int alpha, int pad, const char *fmt, ...)
  290. {
  291. if (y < 0 || x < 0) {
  292. return 0;
  293. } else {
  294. va_list v;
  295. va_start(v, fmt);
  296. stbiw__writefv(s, fmt, v);
  297. va_end(v);
  298. stbiw__write_pixels(s,rgb_dir,vdir,x,y,comp,data,alpha,pad, expand_mono);
  299. return 1;
  300. }
  301. }
  302. static int stbi_write_bmp_core(stbi__write_context *s, int x, int y, int comp, const void *data)
  303. {
  304. int pad = (-x*3) & 3;
  305. return stbiw__outfile(s,-1,-1,x,y,comp,1,(void *) data,0,pad,
  306. "11 4 22 4" "4 44 22 444444",
  307. 'B', 'M', 14+40+(x*3+pad)*y, 0,0, 14+40, // file header
  308. 40, x,y, 1,24, 0,0,0,0,0,0); // bitmap header
  309. }
  310. STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
  311. {
  312. stbi__write_context s;
  313. stbi__start_write_callbacks(&s, func, context);
  314. return stbi_write_bmp_core(&s, x, y, comp, data);
  315. }
  316. #ifndef STBI_WRITE_NO_STDIO
  317. STBIWDEF int stbi_write_bmp(char const *filename, int x, int y, int comp, const void *data)
  318. {
  319. stbi__write_context s;
  320. if (stbi__start_write_file(&s,filename)) {
  321. int r = stbi_write_bmp_core(&s, x, y, comp, data);
  322. stbi__end_write_file(&s);
  323. return r;
  324. } else
  325. return 0;
  326. }
  327. #endif //!STBI_WRITE_NO_STDIO
  328. static int stbi_write_tga_core(stbi__write_context *s, int x, int y, int comp, void *data)
  329. {
  330. int has_alpha = (comp == 2 || comp == 4);
  331. int colorbytes = has_alpha ? comp-1 : comp;
  332. int format = colorbytes < 2 ? 3 : 2; // 3 color channels (RGB/RGBA) = 2, 1 color channel (Y/YA) = 3
  333. if (y < 0 || x < 0)
  334. return 0;
  335. if (!stbi_write_tga_with_rle) {
  336. return stbiw__outfile(s, -1, -1, x, y, comp, 0, (void *) data, has_alpha, 0,
  337. "111 221 2222 11", 0, 0, format, 0, 0, 0, 0, 0, x, y, (colorbytes + has_alpha) * 8, has_alpha * 8);
  338. } else {
  339. int i,j,k;
  340. stbiw__writef(s, "111 221 2222 11", 0,0,format+8, 0,0,0, 0,0,x,y, (colorbytes + has_alpha) * 8, has_alpha * 8);
  341. for (j = y - 1; j >= 0; --j) {
  342. unsigned char *row = (unsigned char *) data + j * x * comp;
  343. int len;
  344. for (i = 0; i < x; i += len) {
  345. unsigned char *begin = row + i * comp;
  346. int diff = 1;
  347. len = 1;
  348. if (i < x - 1) {
  349. ++len;
  350. diff = memcmp(begin, row + (i + 1) * comp, comp);
  351. if (diff) {
  352. const unsigned char *prev = begin;
  353. for (k = i + 2; k < x && len < 128; ++k) {
  354. if (memcmp(prev, row + k * comp, comp)) {
  355. prev += comp;
  356. ++len;
  357. } else {
  358. --len;
  359. break;
  360. }
  361. }
  362. } else {
  363. for (k = i + 2; k < x && len < 128; ++k) {
  364. if (!memcmp(begin, row + k * comp, comp)) {
  365. ++len;
  366. } else {
  367. break;
  368. }
  369. }
  370. }
  371. }
  372. if (diff) {
  373. unsigned char header = STBIW_UCHAR(len - 1);
  374. s->func(s->context, &header, 1);
  375. for (k = 0; k < len; ++k) {
  376. stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin + k * comp);
  377. }
  378. } else {
  379. unsigned char header = STBIW_UCHAR(len - 129);
  380. s->func(s->context, &header, 1);
  381. stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin);
  382. }
  383. }
  384. }
  385. }
  386. return 1;
  387. }
  388. STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
  389. {
  390. stbi__write_context s;
  391. stbi__start_write_callbacks(&s, func, context);
  392. return stbi_write_tga_core(&s, x, y, comp, (void *) data);
  393. }
  394. #ifndef STBI_WRITE_NO_STDIO
  395. STBIWDEF int stbi_write_tga(char const *filename, int x, int y, int comp, const void *data)
  396. {
  397. stbi__write_context s;
  398. if (stbi__start_write_file(&s,filename)) {
  399. int r = stbi_write_tga_core(&s, x, y, comp, (void *) data);
  400. stbi__end_write_file(&s);
  401. return r;
  402. } else
  403. return 0;
  404. }
  405. #endif
  406. // *************************************************************************************************
  407. // Radiance RGBE HDR writer
  408. // by Baldur Karlsson
  409. #define stbiw__max(a, b) ((a) > (b) ? (a) : (b))
  410. void stbiw__linear_to_rgbe(unsigned char *rgbe, float *linear)
  411. {
  412. int exponent;
  413. float maxcomp = stbiw__max(linear[0], stbiw__max(linear[1], linear[2]));
  414. if (maxcomp < 1e-32f) {
  415. rgbe[0] = rgbe[1] = rgbe[2] = rgbe[3] = 0;
  416. } else {
  417. float normalize = (float) frexp(maxcomp, &exponent) * 256.0f/maxcomp;
  418. rgbe[0] = (unsigned char)(linear[0] * normalize);
  419. rgbe[1] = (unsigned char)(linear[1] * normalize);
  420. rgbe[2] = (unsigned char)(linear[2] * normalize);
  421. rgbe[3] = (unsigned char)(exponent + 128);
  422. }
  423. }
  424. void stbiw__write_run_data(stbi__write_context *s, int length, unsigned char databyte)
  425. {
  426. unsigned char lengthbyte = STBIW_UCHAR(length+128);
  427. STBIW_ASSERT(length+128 <= 255);
  428. s->func(s->context, &lengthbyte, 1);
  429. s->func(s->context, &databyte, 1);
  430. }
  431. void stbiw__write_dump_data(stbi__write_context *s, int length, unsigned char *data)
  432. {
  433. unsigned char lengthbyte = STBIW_UCHAR(length);
  434. STBIW_ASSERT(length <= 128); // inconsistent with spec but consistent with official code
  435. s->func(s->context, &lengthbyte, 1);
  436. s->func(s->context, data, length);
  437. }
  438. void stbiw__write_hdr_scanline(stbi__write_context *s, int width, int ncomp, unsigned char *scratch, float *scanline)
  439. {
  440. unsigned char scanlineheader[4] = { 2, 2, 0, 0 };
  441. unsigned char rgbe[4];
  442. float linear[3];
  443. int x;
  444. scanlineheader[2] = (width&0xff00)>>8;
  445. scanlineheader[3] = (width&0x00ff);
  446. /* skip RLE for images too small or large */
  447. if (width < 8 || width >= 32768) {
  448. for (x=0; x < width; x++) {
  449. switch (ncomp) {
  450. case 4: /* fallthrough */
  451. case 3: linear[2] = scanline[x*ncomp + 2];
  452. linear[1] = scanline[x*ncomp + 1];
  453. linear[0] = scanline[x*ncomp + 0];
  454. break;
  455. default:
  456. linear[0] = linear[1] = linear[2] = scanline[x*ncomp + 0];
  457. break;
  458. }
  459. stbiw__linear_to_rgbe(rgbe, linear);
  460. s->func(s->context, rgbe, 4);
  461. }
  462. } else {
  463. int c,r;
  464. /* encode into scratch buffer */
  465. for (x=0; x < width; x++) {
  466. switch(ncomp) {
  467. case 4: /* fallthrough */
  468. case 3: linear[2] = scanline[x*ncomp + 2];
  469. linear[1] = scanline[x*ncomp + 1];
  470. linear[0] = scanline[x*ncomp + 0];
  471. break;
  472. default:
  473. linear[0] = linear[1] = linear[2] = scanline[x*ncomp + 0];
  474. break;
  475. }
  476. stbiw__linear_to_rgbe(rgbe, linear);
  477. scratch[x + width*0] = rgbe[0];
  478. scratch[x + width*1] = rgbe[1];
  479. scratch[x + width*2] = rgbe[2];
  480. scratch[x + width*3] = rgbe[3];
  481. }
  482. s->func(s->context, scanlineheader, 4);
  483. /* RLE each component separately */
  484. for (c=0; c < 4; c++) {
  485. unsigned char *comp = &scratch[width*c];
  486. x = 0;
  487. while (x < width) {
  488. // find first run
  489. r = x;
  490. while (r+2 < width) {
  491. if (comp[r] == comp[r+1] && comp[r] == comp[r+2])
  492. break;
  493. ++r;
  494. }
  495. if (r+2 >= width)
  496. r = width;
  497. // dump up to first run
  498. while (x < r) {
  499. int len = r-x;
  500. if (len > 128) len = 128;
  501. stbiw__write_dump_data(s, len, &comp[x]);
  502. x += len;
  503. }
  504. // if there's a run, output it
  505. if (r+2 < width) { // same test as what we break out of in search loop, so only true if we break'd
  506. // find next byte after run
  507. while (r < width && comp[r] == comp[x])
  508. ++r;
  509. // output run up to r
  510. while (x < r) {
  511. int len = r-x;
  512. if (len > 127) len = 127;
  513. stbiw__write_run_data(s, len, comp[x]);
  514. x += len;
  515. }
  516. }
  517. }
  518. }
  519. }
  520. }
  521. static int stbi_write_hdr_core(stbi__write_context *s, int x, int y, int comp, float *data)
  522. {
  523. if (y <= 0 || x <= 0 || data == NULL)
  524. return 0;
  525. else {
  526. // Each component is stored separately. Allocate scratch space for full output scanline.
  527. unsigned char *scratch = (unsigned char *) STBIW_MALLOC(x*4);
  528. int i, len;
  529. char buffer[128];
  530. char header[] = "#?RADIANCE\n# Written by stb_image_write.h\nFORMAT=32-bit_rle_rgbe\n";
  531. s->func(s->context, header, sizeof(header)-1);
  532. len = sprintf(buffer, "EXPOSURE= 1.0000000000000\n\n-Y %d +X %d\n", y, x);
  533. s->func(s->context, buffer, len);
  534. for(i=0; i < y; i++)
  535. stbiw__write_hdr_scanline(s, x, comp, scratch, data + comp*i*x);
  536. STBIW_FREE(scratch);
  537. return 1;
  538. }
  539. }
  540. STBIWDEF int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const float *data)
  541. {
  542. stbi__write_context s;
  543. stbi__start_write_callbacks(&s, func, context);
  544. return stbi_write_hdr_core(&s, x, y, comp, (float *) data);
  545. }
  546. #ifndef STBI_WRITE_NO_STDIO
  547. STBIWDEF int stbi_write_hdr(char const *filename, int x, int y, int comp, const float *data)
  548. {
  549. stbi__write_context s;
  550. if (stbi__start_write_file(&s,filename)) {
  551. int r = stbi_write_hdr_core(&s, x, y, comp, (float *) data);
  552. stbi__end_write_file(&s);
  553. return r;
  554. } else
  555. return 0;
  556. }
  557. #endif // STBI_WRITE_NO_STDIO
  558. //////////////////////////////////////////////////////////////////////////////
  559. //
  560. // PNG writer
  561. //
  562. // stretchy buffer; stbiw__sbpush() == vector<>::push_back() -- stbiw__sbcount() == vector<>::size()
  563. #define stbiw__sbraw(a) ((int *) (a) - 2)
  564. #define stbiw__sbm(a) stbiw__sbraw(a)[0]
  565. #define stbiw__sbn(a) stbiw__sbraw(a)[1]
  566. #define stbiw__sbneedgrow(a,n) ((a)==0 || stbiw__sbn(a)+n >= stbiw__sbm(a))
  567. #define stbiw__sbmaybegrow(a,n) (stbiw__sbneedgrow(a,(n)) ? stbiw__sbgrow(a,n) : 0)
  568. #define stbiw__sbgrow(a,n) stbiw__sbgrowf((void **) &(a), (n), sizeof(*(a)))
  569. #define stbiw__sbpush(a, v) (stbiw__sbmaybegrow(a,1), (a)[stbiw__sbn(a)++] = (v))
  570. #define stbiw__sbcount(a) ((a) ? stbiw__sbn(a) : 0)
  571. #define stbiw__sbfree(a) ((a) ? STBIW_FREE(stbiw__sbraw(a)),0 : 0)
  572. static void *stbiw__sbgrowf(void **arr, int increment, int itemsize)
  573. {
  574. int m = *arr ? 2*stbiw__sbm(*arr)+increment : increment+1;
  575. void *p = STBIW_REALLOC_SIZED(*arr ? stbiw__sbraw(*arr) : 0, *arr ? (stbiw__sbm(*arr)*itemsize + sizeof(int)*2) : 0, itemsize * m + sizeof(int)*2);
  576. STBIW_ASSERT(p);
  577. if (p) {
  578. if (!*arr) ((int *) p)[1] = 0;
  579. *arr = (void *) ((int *) p + 2);
  580. stbiw__sbm(*arr) = m;
  581. }
  582. return *arr;
  583. }
  584. static unsigned char *stbiw__zlib_flushf(unsigned char *data, unsigned int *bitbuffer, int *bitcount)
  585. {
  586. while (*bitcount >= 8) {
  587. stbiw__sbpush(data, STBIW_UCHAR(*bitbuffer));
  588. *bitbuffer >>= 8;
  589. *bitcount -= 8;
  590. }
  591. return data;
  592. }
  593. static int stbiw__zlib_bitrev(int code, int codebits)
  594. {
  595. int res=0;
  596. while (codebits--) {
  597. res = (res << 1) | (code & 1);
  598. code >>= 1;
  599. }
  600. return res;
  601. }
  602. static unsigned int stbiw__zlib_countm(unsigned char *a, unsigned char *b, int limit)
  603. {
  604. int i;
  605. for (i=0; i < limit && i < 258; ++i)
  606. if (a[i] != b[i]) break;
  607. return i;
  608. }
  609. static unsigned int stbiw__zhash(unsigned char *data)
  610. {
  611. stbiw_uint32 hash = data[0] + (data[1] << 8) + (data[2] << 16);
  612. hash ^= hash << 3;
  613. hash += hash >> 5;
  614. hash ^= hash << 4;
  615. hash += hash >> 17;
  616. hash ^= hash << 25;
  617. hash += hash >> 6;
  618. return hash;
  619. }
  620. #define stbiw__zlib_flush() (out = stbiw__zlib_flushf(out, &bitbuf, &bitcount))
  621. #define stbiw__zlib_add(code,codebits) \
  622. (bitbuf |= (code) << bitcount, bitcount += (codebits), stbiw__zlib_flush())
  623. #define stbiw__zlib_huffa(b,c) stbiw__zlib_add(stbiw__zlib_bitrev(b,c),c)
  624. // default huffman tables
  625. #define stbiw__zlib_huff1(n) stbiw__zlib_huffa(0x30 + (n), 8)
  626. #define stbiw__zlib_huff2(n) stbiw__zlib_huffa(0x190 + (n)-144, 9)
  627. #define stbiw__zlib_huff3(n) stbiw__zlib_huffa(0 + (n)-256,7)
  628. #define stbiw__zlib_huff4(n) stbiw__zlib_huffa(0xc0 + (n)-280,8)
  629. #define stbiw__zlib_huff(n) ((n) <= 143 ? stbiw__zlib_huff1(n) : (n) <= 255 ? stbiw__zlib_huff2(n) : (n) <= 279 ? stbiw__zlib_huff3(n) : stbiw__zlib_huff4(n))
  630. #define stbiw__zlib_huffb(n) ((n) <= 143 ? stbiw__zlib_huff1(n) : stbiw__zlib_huff2(n))
  631. #define stbiw__ZHASH 16384
  632. unsigned char * stbi_zlib_compress(unsigned char *data, int data_len, int *out_len, int quality)
  633. {
  634. static unsigned short lengthc[] = { 3,4,5,6,7,8,9,10,11,13,15,17,19,23,27,31,35,43,51,59,67,83,99,115,131,163,195,227,258, 259 };
  635. static unsigned char lengtheb[]= { 0,0,0,0,0,0,0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0 };
  636. static unsigned short distc[] = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193,257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577, 32768 };
  637. static unsigned char disteb[] = { 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13 };
  638. unsigned int bitbuf=0;
  639. int i,j, bitcount=0;
  640. unsigned char *out = NULL;
  641. unsigned char ***hash_table = (unsigned char***) STBIW_MALLOC(stbiw__ZHASH * sizeof(char**));
  642. if (quality < 5) quality = 5;
  643. stbiw__sbpush(out, 0x78); // DEFLATE 32K window
  644. stbiw__sbpush(out, 0x5e); // FLEVEL = 1
  645. stbiw__zlib_add(1,1); // BFINAL = 1
  646. stbiw__zlib_add(1,2); // BTYPE = 1 -- fixed huffman
  647. for (i=0; i < stbiw__ZHASH; ++i)
  648. hash_table[i] = NULL;
  649. i=0;
  650. while (i < data_len-3) {
  651. // hash next 3 bytes of data to be compressed
  652. int h = stbiw__zhash(data+i)&(stbiw__ZHASH-1), best=3;
  653. unsigned char *bestloc = 0;
  654. unsigned char **hlist = hash_table[h];
  655. int n = stbiw__sbcount(hlist);
  656. for (j=0; j < n; ++j) {
  657. if (hlist[j]-data > i-32768) { // if entry lies within window
  658. int d = stbiw__zlib_countm(hlist[j], data+i, data_len-i);
  659. if (d >= best) best=d,bestloc=hlist[j];
  660. }
  661. }
  662. // when hash table entry is too long, delete half the entries
  663. if (hash_table[h] && stbiw__sbn(hash_table[h]) == 2*quality) {
  664. STBIW_MEMMOVE(hash_table[h], hash_table[h]+quality, sizeof(hash_table[h][0])*quality);
  665. stbiw__sbn(hash_table[h]) = quality;
  666. }
  667. stbiw__sbpush(hash_table[h],data+i);
  668. if (bestloc) {
  669. // "lazy matching" - check match at *next* byte, and if it's better, do cur byte as literal
  670. h = stbiw__zhash(data+i+1)&(stbiw__ZHASH-1);
  671. hlist = hash_table[h];
  672. n = stbiw__sbcount(hlist);
  673. for (j=0; j < n; ++j) {
  674. if (hlist[j]-data > i-32767) {
  675. int e = stbiw__zlib_countm(hlist[j], data+i+1, data_len-i-1);
  676. if (e > best) { // if next match is better, bail on current match
  677. bestloc = NULL;
  678. break;
  679. }
  680. }
  681. }
  682. }
  683. if (bestloc) {
  684. int d = (int) (data+i - bestloc); // distance back
  685. STBIW_ASSERT(d <= 32767 && best <= 258);
  686. for (j=0; best > lengthc[j+1]-1; ++j);
  687. stbiw__zlib_huff(j+257);
  688. if (lengtheb[j]) stbiw__zlib_add(best - lengthc[j], lengtheb[j]);
  689. for (j=0; d > distc[j+1]-1; ++j);
  690. stbiw__zlib_add(stbiw__zlib_bitrev(j,5),5);
  691. if (disteb[j]) stbiw__zlib_add(d - distc[j], disteb[j]);
  692. i += best;
  693. } else {
  694. stbiw__zlib_huffb(data[i]);
  695. ++i;
  696. }
  697. }
  698. // write out final bytes
  699. for (;i < data_len; ++i)
  700. stbiw__zlib_huffb(data[i]);
  701. stbiw__zlib_huff(256); // end of block
  702. // pad with 0 bits to byte boundary
  703. while (bitcount)
  704. stbiw__zlib_add(0,1);
  705. for (i=0; i < stbiw__ZHASH; ++i)
  706. (void) stbiw__sbfree(hash_table[i]);
  707. STBIW_FREE(hash_table);
  708. {
  709. // compute adler32 on input
  710. unsigned int s1=1, s2=0;
  711. int blocklen = (int) (data_len % 5552);
  712. j=0;
  713. while (j < data_len) {
  714. for (i=0; i < blocklen; ++i) s1 += data[j+i], s2 += s1;
  715. s1 %= 65521, s2 %= 65521;
  716. j += blocklen;
  717. blocklen = 5552;
  718. }
  719. stbiw__sbpush(out, STBIW_UCHAR(s2 >> 8));
  720. stbiw__sbpush(out, STBIW_UCHAR(s2));
  721. stbiw__sbpush(out, STBIW_UCHAR(s1 >> 8));
  722. stbiw__sbpush(out, STBIW_UCHAR(s1));
  723. }
  724. *out_len = stbiw__sbn(out);
  725. // make returned pointer freeable
  726. STBIW_MEMMOVE(stbiw__sbraw(out), out, *out_len);
  727. return (unsigned char *) stbiw__sbraw(out);
  728. }
  729. static unsigned int stbiw__crc32(unsigned char *buffer, int len)
  730. {
  731. static unsigned int crc_table[256] =
  732. {
  733. 0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
  734. 0x0eDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
  735. 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
  736. 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
  737. 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
  738. 0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
  739. 0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
  740. 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
  741. 0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
  742. 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
  743. 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
  744. 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
  745. 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
  746. 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
  747. 0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
  748. 0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
  749. 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
  750. 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
  751. 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
  752. 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
  753. 0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
  754. 0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
  755. 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
  756. 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
  757. 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
  758. 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
  759. 0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
  760. 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
  761. 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
  762. 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
  763. 0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
  764. 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
  765. };
  766. unsigned int crc = ~0u;
  767. int i;
  768. for (i=0; i < len; ++i)
  769. crc = (crc >> 8) ^ crc_table[buffer[i] ^ (crc & 0xff)];
  770. return ~crc;
  771. }
  772. #define stbiw__wpng4(o,a,b,c,d) ((o)[0]=STBIW_UCHAR(a),(o)[1]=STBIW_UCHAR(b),(o)[2]=STBIW_UCHAR(c),(o)[3]=STBIW_UCHAR(d),(o)+=4)
  773. #define stbiw__wp32(data,v) stbiw__wpng4(data, (v)>>24,(v)>>16,(v)>>8,(v));
  774. #define stbiw__wptag(data,s) stbiw__wpng4(data, s[0],s[1],s[2],s[3])
  775. static void stbiw__wpcrc(unsigned char **data, int len)
  776. {
  777. unsigned int crc = stbiw__crc32(*data - len - 4, len+4);
  778. stbiw__wp32(*data, crc);
  779. }
  780. static unsigned char stbiw__paeth(int a, int b, int c)
  781. {
  782. int p = a + b - c, pa = abs(p-a), pb = abs(p-b), pc = abs(p-c);
  783. if (pa <= pb && pa <= pc) return STBIW_UCHAR(a);
  784. if (pb <= pc) return STBIW_UCHAR(b);
  785. return STBIW_UCHAR(c);
  786. }
  787. // @OPTIMIZE: provide an option that always forces left-predict or paeth predict
  788. unsigned char *stbi_write_png_to_mem(unsigned char *pixels, int stride_bytes, int x, int y, int n, int *out_len)
  789. {
  790. int ctype[5] = { -1, 0, 4, 2, 6 };
  791. unsigned char sig[8] = { 137,80,78,71,13,10,26,10 };
  792. unsigned char *out,*o, *filt, *zlib;
  793. signed char *line_buffer;
  794. int i,j,k,p,zlen;
  795. if (stride_bytes == 0)
  796. stride_bytes = x * n;
  797. filt = (unsigned char *) STBIW_MALLOC((x*n+1) * y); if (!filt) return 0;
  798. line_buffer = (signed char *) STBIW_MALLOC(x * n); if (!line_buffer) { STBIW_FREE(filt); return 0; }
  799. for (j=0; j < y; ++j) {
  800. static int mapping[] = { 0,1,2,3,4 };
  801. static int firstmap[] = { 0,1,0,5,6 };
  802. int *mymap = (j != 0) ? mapping : firstmap;
  803. int best = 0, bestval = 0x7fffffff;
  804. for (p=0; p < 2; ++p) {
  805. for (k= p?best:0; k < 5; ++k) { // @TODO: clarity: rewrite this to go 0..5, and 'continue' the unwanted ones during 2nd pass
  806. int type = mymap[k],est=0;
  807. unsigned char *z = pixels + stride_bytes*j;
  808. for (i=0; i < n; ++i)
  809. switch (type) {
  810. case 0: line_buffer[i] = z[i]; break;
  811. case 1: line_buffer[i] = z[i]; break;
  812. case 2: line_buffer[i] = z[i] - z[i-stride_bytes]; break;
  813. case 3: line_buffer[i] = z[i] - (z[i-stride_bytes]>>1); break;
  814. case 4: line_buffer[i] = (signed char) (z[i] - stbiw__paeth(0,z[i-stride_bytes],0)); break;
  815. case 5: line_buffer[i] = z[i]; break;
  816. case 6: line_buffer[i] = z[i]; break;
  817. }
  818. for (i=n; i < x*n; ++i) {
  819. switch (type) {
  820. case 0: line_buffer[i] = z[i]; break;
  821. case 1: line_buffer[i] = z[i] - z[i-n]; break;
  822. case 2: line_buffer[i] = z[i] - z[i-stride_bytes]; break;
  823. case 3: line_buffer[i] = z[i] - ((z[i-n] + z[i-stride_bytes])>>1); break;
  824. case 4: line_buffer[i] = z[i] - stbiw__paeth(z[i-n], z[i-stride_bytes], z[i-stride_bytes-n]); break;
  825. case 5: line_buffer[i] = z[i] - (z[i-n]>>1); break;
  826. case 6: line_buffer[i] = z[i] - stbiw__paeth(z[i-n], 0,0); break;
  827. }
  828. }
  829. if (p) break;
  830. for (i=0; i < x*n; ++i)
  831. est += abs((signed char) line_buffer[i]);
  832. if (est < bestval) { bestval = est; best = k; }
  833. }
  834. }
  835. // when we get here, best contains the filter type, and line_buffer contains the data
  836. filt[j*(x*n+1)] = (unsigned char) best;
  837. STBIW_MEMMOVE(filt+j*(x*n+1)+1, line_buffer, x*n);
  838. }
  839. STBIW_FREE(line_buffer);
  840. zlib = stbi_zlib_compress(filt, y*( x*n+1), &zlen, 8); // increase 8 to get smaller but use more memory
  841. STBIW_FREE(filt);
  842. if (!zlib) return 0;
  843. // each tag requires 12 bytes of overhead
  844. out = (unsigned char *) STBIW_MALLOC(8 + 12+13 + 12+zlen + 12);
  845. if (!out) return 0;
  846. *out_len = 8 + 12+13 + 12+zlen + 12;
  847. o=out;
  848. STBIW_MEMMOVE(o,sig,8); o+= 8;
  849. stbiw__wp32(o, 13); // header length
  850. stbiw__wptag(o, "IHDR");
  851. stbiw__wp32(o, x);
  852. stbiw__wp32(o, y);
  853. *o++ = 8;
  854. *o++ = STBIW_UCHAR(ctype[n]);
  855. *o++ = 0;
  856. *o++ = 0;
  857. *o++ = 0;
  858. stbiw__wpcrc(&o,13);
  859. stbiw__wp32(o, zlen);
  860. stbiw__wptag(o, "IDAT");
  861. STBIW_MEMMOVE(o, zlib, zlen);
  862. o += zlen;
  863. STBIW_FREE(zlib);
  864. stbiw__wpcrc(&o, zlen);
  865. stbiw__wp32(o,0);
  866. stbiw__wptag(o, "IEND");
  867. stbiw__wpcrc(&o,0);
  868. STBIW_ASSERT(o == out + *out_len);
  869. return out;
  870. }
  871. #ifndef STBI_WRITE_NO_STDIO
  872. STBIWDEF int stbi_write_png(char const *filename, int x, int y, int comp, const void *data, int stride_bytes)
  873. {
  874. FILE *f;
  875. int len;
  876. unsigned char *png = stbi_write_png_to_mem((unsigned char *) data, stride_bytes, x, y, comp, &len);
  877. if (png == NULL) return 0;
  878. f = fopen(filename, "wb");
  879. if (!f) { STBIW_FREE(png); return 0; }
  880. fwrite(png, 1, len, f);
  881. fclose(f);
  882. STBIW_FREE(png);
  883. return 1;
  884. }
  885. #endif
  886. STBIWDEF int stbi_write_png_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int stride_bytes)
  887. {
  888. int len;
  889. unsigned char *png = stbi_write_png_to_mem((unsigned char *) data, stride_bytes, x, y, comp, &len);
  890. if (png == NULL) return 0;
  891. func(context, png, len);
  892. STBIW_FREE(png);
  893. return 1;
  894. }
  895. /* ***************************************************************************
  896. *
  897. * JPEG writer
  898. *
  899. * This is based on Jon Olick's jo_jpeg.cpp:
  900. * public domain Simple, Minimalistic JPEG writer - http://www.jonolick.com/code.html
  901. */
  902. static const unsigned char stbiw__jpg_ZigZag[] = { 0,1,5,6,14,15,27,28,2,4,7,13,16,26,29,42,3,8,12,17,25,30,41,43,9,11,18,
  903. 24,31,40,44,53,10,19,23,32,39,45,52,54,20,22,33,38,46,51,55,60,21,34,37,47,50,56,59,61,35,36,48,49,57,58,62,63 };
  904. static void stbiw__jpg_writeBits(stbi__write_context *s, int *bitBufP, int *bitCntP, const unsigned short *bs) {
  905. int bitBuf = *bitBufP, bitCnt = *bitCntP;
  906. bitCnt += bs[1];
  907. bitBuf |= bs[0] << (24 - bitCnt);
  908. while(bitCnt >= 8) {
  909. unsigned char c = (bitBuf >> 16) & 255;
  910. stbiw__putc(s, c);
  911. if(c == 255) {
  912. stbiw__putc(s, 0);
  913. }
  914. bitBuf <<= 8;
  915. bitCnt -= 8;
  916. }
  917. *bitBufP = bitBuf;
  918. *bitCntP = bitCnt;
  919. }
  920. static void stbiw__jpg_DCT(float *d0p, float *d1p, float *d2p, float *d3p, float *d4p, float *d5p, float *d6p, float *d7p) {
  921. float d0 = *d0p, d1 = *d1p, d2 = *d2p, d3 = *d3p, d4 = *d4p, d5 = *d5p, d6 = *d6p, d7 = *d7p;
  922. float z1, z2, z3, z4, z5, z11, z13;
  923. float tmp0 = d0 + d7;
  924. float tmp7 = d0 - d7;
  925. float tmp1 = d1 + d6;
  926. float tmp6 = d1 - d6;
  927. float tmp2 = d2 + d5;
  928. float tmp5 = d2 - d5;
  929. float tmp3 = d3 + d4;
  930. float tmp4 = d3 - d4;
  931. // Even part
  932. float tmp10 = tmp0 + tmp3; // phase 2
  933. float tmp13 = tmp0 - tmp3;
  934. float tmp11 = tmp1 + tmp2;
  935. float tmp12 = tmp1 - tmp2;
  936. d0 = tmp10 + tmp11; // phase 3
  937. d4 = tmp10 - tmp11;
  938. z1 = (tmp12 + tmp13) * 0.707106781f; // c4
  939. d2 = tmp13 + z1; // phase 5
  940. d6 = tmp13 - z1;
  941. // Odd part
  942. tmp10 = tmp4 + tmp5; // phase 2
  943. tmp11 = tmp5 + tmp6;
  944. tmp12 = tmp6 + tmp7;
  945. // The rotator is modified from fig 4-8 to avoid extra negations.
  946. z5 = (tmp10 - tmp12) * 0.382683433f; // c6
  947. z2 = tmp10 * 0.541196100f + z5; // c2-c6
  948. z4 = tmp12 * 1.306562965f + z5; // c2+c6
  949. z3 = tmp11 * 0.707106781f; // c4
  950. z11 = tmp7 + z3; // phase 5
  951. z13 = tmp7 - z3;
  952. *d5p = z13 + z2; // phase 6
  953. *d3p = z13 - z2;
  954. *d1p = z11 + z4;
  955. *d7p = z11 - z4;
  956. *d0p = d0; *d2p = d2; *d4p = d4; *d6p = d6;
  957. }
  958. static void stbiw__jpg_calcBits(int val, unsigned short bits[2]) {
  959. int tmp1 = val < 0 ? -val : val;
  960. val = val < 0 ? val-1 : val;
  961. bits[1] = 1;
  962. while(tmp1 >>= 1) {
  963. ++bits[1];
  964. }
  965. bits[0] = val & ((1<<bits[1])-1);
  966. }
  967. static int stbiw__jpg_processDU(stbi__write_context *s, int *bitBuf, int *bitCnt, float *CDU, float *fdtbl, int DC, const unsigned short HTDC[256][2], const unsigned short HTAC[256][2]) {
  968. const unsigned short EOB[2] = { HTAC[0x00][0], HTAC[0x00][1] };
  969. const unsigned short M16zeroes[2] = { HTAC[0xF0][0], HTAC[0xF0][1] };
  970. int dataOff, i, diff, end0pos;
  971. int DU[64];
  972. // DCT rows
  973. for(dataOff=0; dataOff<64; dataOff+=8) {
  974. stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+1], &CDU[dataOff+2], &CDU[dataOff+3], &CDU[dataOff+4], &CDU[dataOff+5], &CDU[dataOff+6], &CDU[dataOff+7]);
  975. }
  976. // DCT columns
  977. for(dataOff=0; dataOff<8; ++dataOff) {
  978. stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+8], &CDU[dataOff+16], &CDU[dataOff+24], &CDU[dataOff+32], &CDU[dataOff+40], &CDU[dataOff+48], &CDU[dataOff+56]);
  979. }
  980. // Quantize/descale/zigzag the coefficients
  981. for(i=0; i<64; ++i) {
  982. float v = CDU[i]*fdtbl[i];
  983. // DU[stbiw__jpg_ZigZag[i]] = (int)(v < 0 ? ceilf(v - 0.5f) : floorf(v + 0.5f));
  984. // ceilf() and floorf() are C99, not C89, but I /think/ they're not needed here anyway?
  985. DU[stbiw__jpg_ZigZag[i]] = (int)(v < 0 ? v - 0.5f : v + 0.5f);
  986. }
  987. // Encode DC
  988. diff = DU[0] - DC;
  989. if (diff == 0) {
  990. stbiw__jpg_writeBits(s, bitBuf, bitCnt, HTDC[0]);
  991. } else {
  992. unsigned short bits[2];
  993. stbiw__jpg_calcBits(diff, bits);
  994. stbiw__jpg_writeBits(s, bitBuf, bitCnt, HTDC[bits[1]]);
  995. stbiw__jpg_writeBits(s, bitBuf, bitCnt, bits);
  996. }
  997. // Encode ACs
  998. end0pos = 63;
  999. for(; (end0pos>0)&&(DU[end0pos]==0); --end0pos) {
  1000. }
  1001. // end0pos = first element in reverse order !=0
  1002. if(end0pos == 0) {
  1003. stbiw__jpg_writeBits(s, bitBuf, bitCnt, EOB);
  1004. return DU[0];
  1005. }
  1006. for(i = 1; i <= end0pos; ++i) {
  1007. int startpos = i;
  1008. int nrzeroes;
  1009. unsigned short bits[2];
  1010. for (; DU[i]==0 && i<=end0pos; ++i) {
  1011. }
  1012. nrzeroes = i-startpos;
  1013. if ( nrzeroes >= 16 ) {
  1014. int lng = nrzeroes>>4;
  1015. int nrmarker;
  1016. for (nrmarker=1; nrmarker <= lng; ++nrmarker)
  1017. stbiw__jpg_writeBits(s, bitBuf, bitCnt, M16zeroes);
  1018. nrzeroes &= 15;
  1019. }
  1020. stbiw__jpg_calcBits(DU[i], bits);
  1021. stbiw__jpg_writeBits(s, bitBuf, bitCnt, HTAC[(nrzeroes<<4)+bits[1]]);
  1022. stbiw__jpg_writeBits(s, bitBuf, bitCnt, bits);
  1023. }
  1024. if(end0pos != 63) {
  1025. stbiw__jpg_writeBits(s, bitBuf, bitCnt, EOB);
  1026. }
  1027. return DU[0];
  1028. }
  1029. static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, int comp, const void* data, int quality) {
  1030. // Constants that don't pollute global namespace
  1031. static const unsigned char std_dc_luminance_nrcodes[] = {0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0};
  1032. static const unsigned char std_dc_luminance_values[] = {0,1,2,3,4,5,6,7,8,9,10,11};
  1033. static const unsigned char std_ac_luminance_nrcodes[] = {0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d};
  1034. static const unsigned char std_ac_luminance_values[] = {
  1035. 0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12,0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07,0x22,0x71,0x14,0x32,0x81,0x91,0xa1,0x08,
  1036. 0x23,0x42,0xb1,0xc1,0x15,0x52,0xd1,0xf0,0x24,0x33,0x62,0x72,0x82,0x09,0x0a,0x16,0x17,0x18,0x19,0x1a,0x25,0x26,0x27,0x28,
  1037. 0x29,0x2a,0x34,0x35,0x36,0x37,0x38,0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58,0x59,
  1038. 0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a,0x83,0x84,0x85,0x86,0x87,0x88,0x89,
  1039. 0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,0xb5,0xb6,
  1040. 0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xe1,0xe2,
  1041. 0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,0xf9,0xfa
  1042. };
  1043. static const unsigned char std_dc_chrominance_nrcodes[] = {0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0};
  1044. static const unsigned char std_dc_chrominance_values[] = {0,1,2,3,4,5,6,7,8,9,10,11};
  1045. static const unsigned char std_ac_chrominance_nrcodes[] = {0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77};
  1046. static const unsigned char std_ac_chrominance_values[] = {
  1047. 0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21,0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71,0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91,
  1048. 0xa1,0xb1,0xc1,0x09,0x23,0x33,0x52,0xf0,0x15,0x62,0x72,0xd1,0x0a,0x16,0x24,0x34,0xe1,0x25,0xf1,0x17,0x18,0x19,0x1a,0x26,
  1049. 0x27,0x28,0x29,0x2a,0x35,0x36,0x37,0x38,0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58,
  1050. 0x59,0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a,0x82,0x83,0x84,0x85,0x86,0x87,
  1051. 0x88,0x89,0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,
  1052. 0xb5,0xb6,0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,
  1053. 0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,0xf9,0xfa
  1054. };
  1055. // Huffman tables
  1056. static const unsigned short YDC_HT[256][2] = { {0,2},{2,3},{3,3},{4,3},{5,3},{6,3},{14,4},{30,5},{62,6},{126,7},{254,8},{510,9}};
  1057. static const unsigned short UVDC_HT[256][2] = { {0,2},{1,2},{2,2},{6,3},{14,4},{30,5},{62,6},{126,7},{254,8},{510,9},{1022,10},{2046,11}};
  1058. static const unsigned short YAC_HT[256][2] = {
  1059. {10,4},{0,2},{1,2},{4,3},{11,4},{26,5},{120,7},{248,8},{1014,10},{65410,16},{65411,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1060. {12,4},{27,5},{121,7},{502,9},{2038,11},{65412,16},{65413,16},{65414,16},{65415,16},{65416,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1061. {28,5},{249,8},{1015,10},{4084,12},{65417,16},{65418,16},{65419,16},{65420,16},{65421,16},{65422,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1062. {58,6},{503,9},{4085,12},{65423,16},{65424,16},{65425,16},{65426,16},{65427,16},{65428,16},{65429,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1063. {59,6},{1016,10},{65430,16},{65431,16},{65432,16},{65433,16},{65434,16},{65435,16},{65436,16},{65437,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1064. {122,7},{2039,11},{65438,16},{65439,16},{65440,16},{65441,16},{65442,16},{65443,16},{65444,16},{65445,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1065. {123,7},{4086,12},{65446,16},{65447,16},{65448,16},{65449,16},{65450,16},{65451,16},{65452,16},{65453,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1066. {250,8},{4087,12},{65454,16},{65455,16},{65456,16},{65457,16},{65458,16},{65459,16},{65460,16},{65461,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1067. {504,9},{32704,15},{65462,16},{65463,16},{65464,16},{65465,16},{65466,16},{65467,16},{65468,16},{65469,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1068. {505,9},{65470,16},{65471,16},{65472,16},{65473,16},{65474,16},{65475,16},{65476,16},{65477,16},{65478,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1069. {506,9},{65479,16},{65480,16},{65481,16},{65482,16},{65483,16},{65484,16},{65485,16},{65486,16},{65487,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1070. {1017,10},{65488,16},{65489,16},{65490,16},{65491,16},{65492,16},{65493,16},{65494,16},{65495,16},{65496,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1071. {1018,10},{65497,16},{65498,16},{65499,16},{65500,16},{65501,16},{65502,16},{65503,16},{65504,16},{65505,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1072. {2040,11},{65506,16},{65507,16},{65508,16},{65509,16},{65510,16},{65511,16},{65512,16},{65513,16},{65514,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1073. {65515,16},{65516,16},{65517,16},{65518,16},{65519,16},{65520,16},{65521,16},{65522,16},{65523,16},{65524,16},{0,0},{0,0},{0,0},{0,0},{0,0},
  1074. {2041,11},{65525,16},{65526,16},{65527,16},{65528,16},{65529,16},{65530,16},{65531,16},{65532,16},{65533,16},{65534,16},{0,0},{0,0},{0,0},{0,0},{0,0}
  1075. };
  1076. static const unsigned short UVAC_HT[256][2] = {
  1077. {0,2},{1,2},{4,3},{10,4},{24,5},{25,5},{56,6},{120,7},{500,9},{1014,10},{4084,12},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1078. {11,4},{57,6},{246,8},{501,9},{2038,11},{4085,12},{65416,16},{65417,16},{65418,16},{65419,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1079. {26,5},{247,8},{1015,10},{4086,12},{32706,15},{65420,16},{65421,16},{65422,16},{65423,16},{65424,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1080. {27,5},{248,8},{1016,10},{4087,12},{65425,16},{65426,16},{65427,16},{65428,16},{65429,16},{65430,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1081. {58,6},{502,9},{65431,16},{65432,16},{65433,16},{65434,16},{65435,16},{65436,16},{65437,16},{65438,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1082. {59,6},{1017,10},{65439,16},{65440,16},{65441,16},{65442,16},{65443,16},{65444,16},{65445,16},{65446,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1083. {121,7},{2039,11},{65447,16},{65448,16},{65449,16},{65450,16},{65451,16},{65452,16},{65453,16},{65454,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1084. {122,7},{2040,11},{65455,16},{65456,16},{65457,16},{65458,16},{65459,16},{65460,16},{65461,16},{65462,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1085. {249,8},{65463,16},{65464,16},{65465,16},{65466,16},{65467,16},{65468,16},{65469,16},{65470,16},{65471,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1086. {503,9},{65472,16},{65473,16},{65474,16},{65475,16},{65476,16},{65477,16},{65478,16},{65479,16},{65480,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1087. {504,9},{65481,16},{65482,16},{65483,16},{65484,16},{65485,16},{65486,16},{65487,16},{65488,16},{65489,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1088. {505,9},{65490,16},{65491,16},{65492,16},{65493,16},{65494,16},{65495,16},{65496,16},{65497,16},{65498,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1089. {506,9},{65499,16},{65500,16},{65501,16},{65502,16},{65503,16},{65504,16},{65505,16},{65506,16},{65507,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1090. {2041,11},{65508,16},{65509,16},{65510,16},{65511,16},{65512,16},{65513,16},{65514,16},{65515,16},{65516,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  1091. {16352,14},{65517,16},{65518,16},{65519,16},{65520,16},{65521,16},{65522,16},{65523,16},{65524,16},{65525,16},{0,0},{0,0},{0,0},{0,0},{0,0},
  1092. {1018,10},{32707,15},{65526,16},{65527,16},{65528,16},{65529,16},{65530,16},{65531,16},{65532,16},{65533,16},{65534,16},{0,0},{0,0},{0,0},{0,0},{0,0}
  1093. };
  1094. static const int YQT[] = {16,11,10,16,24,40,51,61,12,12,14,19,26,58,60,55,14,13,16,24,40,57,69,56,14,17,22,29,51,87,80,62,18,22,
  1095. 37,56,68,109,103,77,24,35,55,64,81,104,113,92,49,64,78,87,103,121,120,101,72,92,95,98,112,100,103,99};
  1096. static const int UVQT[] = {17,18,24,47,99,99,99,99,18,21,26,66,99,99,99,99,24,26,56,99,99,99,99,99,47,66,99,99,99,99,99,99,
  1097. 99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99};
  1098. static const float aasf[] = { 1.0f * 2.828427125f, 1.387039845f * 2.828427125f, 1.306562965f * 2.828427125f, 1.175875602f * 2.828427125f,
  1099. 1.0f * 2.828427125f, 0.785694958f * 2.828427125f, 0.541196100f * 2.828427125f, 0.275899379f * 2.828427125f };
  1100. int row, col, i, k;
  1101. float fdtbl_Y[64], fdtbl_UV[64];
  1102. unsigned char YTable[64], UVTable[64];
  1103. if(!data || !width || !height || comp > 4 || comp < 1) {
  1104. return 0;
  1105. }
  1106. quality = quality ? quality : 90;
  1107. quality = quality < 1 ? 1 : quality > 100 ? 100 : quality;
  1108. quality = quality < 50 ? 5000 / quality : 200 - quality * 2;
  1109. for(i = 0; i < 64; ++i) {
  1110. int uvti, yti = (YQT[i]*quality+50)/100;
  1111. YTable[stbiw__jpg_ZigZag[i]] = (unsigned char) (yti < 1 ? 1 : yti > 255 ? 255 : yti);
  1112. uvti = (UVQT[i]*quality+50)/100;
  1113. UVTable[stbiw__jpg_ZigZag[i]] = (unsigned char) (uvti < 1 ? 1 : uvti > 255 ? 255 : uvti);
  1114. }
  1115. for(row = 0, k = 0; row < 8; ++row) {
  1116. for(col = 0; col < 8; ++col, ++k) {
  1117. fdtbl_Y[k] = 1 / (YTable [stbiw__jpg_ZigZag[k]] * aasf[row] * aasf[col]);
  1118. fdtbl_UV[k] = 1 / (UVTable[stbiw__jpg_ZigZag[k]] * aasf[row] * aasf[col]);
  1119. }
  1120. }
  1121. // Write Headers
  1122. {
  1123. static const unsigned char head0[] = { 0xFF,0xD8,0xFF,0xE0,0,0x10,'J','F','I','F',0,1,1,0,0,1,0,1,0,0,0xFF,0xDB,0,0x84,0 };
  1124. static const unsigned char head2[] = { 0xFF,0xDA,0,0xC,3,1,0,2,0x11,3,0x11,0,0x3F,0 };
  1125. const unsigned char head1[] = { 0xFF,0xC0,0,0x11,8,(unsigned char)(height>>8),STBIW_UCHAR(height),(unsigned char)(width>>8),STBIW_UCHAR(width),
  1126. 3,1,0x11,0,2,0x11,1,3,0x11,1,0xFF,0xC4,0x01,0xA2,0 };
  1127. s->func(s->context, (void*)head0, sizeof(head0));
  1128. s->func(s->context, (void*)YTable, sizeof(YTable));
  1129. stbiw__putc(s, 1);
  1130. s->func(s->context, UVTable, sizeof(UVTable));
  1131. s->func(s->context, (void*)head1, sizeof(head1));
  1132. s->func(s->context, (void*)(std_dc_luminance_nrcodes+1), sizeof(std_dc_luminance_nrcodes)-1);
  1133. s->func(s->context, (void*)std_dc_luminance_values, sizeof(std_dc_luminance_values));
  1134. stbiw__putc(s, 0x10); // HTYACinfo
  1135. s->func(s->context, (void*)(std_ac_luminance_nrcodes+1), sizeof(std_ac_luminance_nrcodes)-1);
  1136. s->func(s->context, (void*)std_ac_luminance_values, sizeof(std_ac_luminance_values));
  1137. stbiw__putc(s, 1); // HTUDCinfo
  1138. s->func(s->context, (void*)(std_dc_chrominance_nrcodes+1), sizeof(std_dc_chrominance_nrcodes)-1);
  1139. s->func(s->context, (void*)std_dc_chrominance_values, sizeof(std_dc_chrominance_values));
  1140. stbiw__putc(s, 0x11); // HTUACinfo
  1141. s->func(s->context, (void*)(std_ac_chrominance_nrcodes+1), sizeof(std_ac_chrominance_nrcodes)-1);
  1142. s->func(s->context, (void*)std_ac_chrominance_values, sizeof(std_ac_chrominance_values));
  1143. s->func(s->context, (void*)head2, sizeof(head2));
  1144. }
  1145. // Encode 8x8 macroblocks
  1146. {
  1147. static const unsigned short fillBits[] = {0x7F, 7};
  1148. const unsigned char *imageData = (const unsigned char *)data;
  1149. int DCY=0, DCU=0, DCV=0;
  1150. int bitBuf=0, bitCnt=0;
  1151. // comp == 2 is grey+alpha (alpha is ignored)
  1152. int ofsG = comp > 2 ? 1 : 0, ofsB = comp > 2 ? 2 : 0;
  1153. int x, y, pos;
  1154. for(y = 0; y < height; y += 8) {
  1155. for(x = 0; x < width; x += 8) {
  1156. float YDU[64], UDU[64], VDU[64];
  1157. for(row = y, pos = 0; row < y+8; ++row) {
  1158. for(col = x; col < x+8; ++col, ++pos) {
  1159. int p = row*width*comp + col*comp;
  1160. float r, g, b;
  1161. if(row >= height) {
  1162. p -= width*comp*(row+1 - height);
  1163. }
  1164. if(col >= width) {
  1165. p -= comp*(col+1 - width);
  1166. }
  1167. r = imageData[p+0];
  1168. g = imageData[p+ofsG];
  1169. b = imageData[p+ofsB];
  1170. YDU[pos]=+0.29900f*r+0.58700f*g+0.11400f*b-128;
  1171. UDU[pos]=-0.16874f*r-0.33126f*g+0.50000f*b;
  1172. VDU[pos]=+0.50000f*r-0.41869f*g-0.08131f*b;
  1173. }
  1174. }
  1175. DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
  1176. DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
  1177. DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
  1178. }
  1179. }
  1180. // Do the bit alignment of the EOI marker
  1181. stbiw__jpg_writeBits(s, &bitBuf, &bitCnt, fillBits);
  1182. }
  1183. // EOI
  1184. stbiw__putc(s, 0xFF);
  1185. stbiw__putc(s, 0xD9);
  1186. return 1;
  1187. }
  1188. STBIWDEF int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality)
  1189. {
  1190. stbi__write_context s;
  1191. stbi__start_write_callbacks(&s, func, context);
  1192. return stbi_write_jpg_core(&s, x, y, comp, (void *) data, quality);
  1193. }
  1194. #ifndef STBI_WRITE_NO_STDIO
  1195. STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const void *data, int quality)
  1196. {
  1197. stbi__write_context s;
  1198. if (stbi__start_write_file(&s,filename)) {
  1199. int r = stbi_write_jpg_core(&s, x, y, comp, data, quality);
  1200. stbi__end_write_file(&s);
  1201. return r;
  1202. } else
  1203. return 0;
  1204. }
  1205. #endif
  1206. #endif // STB_IMAGE_WRITE_IMPLEMENTATION
  1207. /* Revision history
  1208. 1.07 (2017-07-24)
  1209. doc fix
  1210. 1.06 (2017-07-23)
  1211. writing JPEG (using Jon Olick's code)
  1212. 1.05 ???
  1213. 1.04 (2017-03-03)
  1214. monochrome BMP expansion
  1215. 1.03 ???
  1216. 1.02 (2016-04-02)
  1217. avoid allocating large structures on the stack
  1218. 1.01 (2016-01-16)
  1219. STBIW_REALLOC_SIZED: support allocators with no realloc support
  1220. avoid race-condition in crc initialization
  1221. minor compile issues
  1222. 1.00 (2015-09-14)
  1223. installable file IO function
  1224. 0.99 (2015-09-13)
  1225. warning fixes; TGA rle support
  1226. 0.98 (2015-04-08)
  1227. added STBIW_MALLOC, STBIW_ASSERT etc
  1228. 0.97 (2015-01-18)
  1229. fixed HDR asserts, rewrote HDR rle logic
  1230. 0.96 (2015-01-17)
  1231. add HDR output
  1232. fix monochrome BMP
  1233. 0.95 (2014-08-17)
  1234. add monochrome TGA output
  1235. 0.94 (2014-05-31)
  1236. rename private functions to avoid conflicts with stb_image.h
  1237. 0.93 (2014-05-27)
  1238. warning fixes
  1239. 0.92 (2010-08-01)
  1240. casts to unsigned char to fix warnings
  1241. 0.91 (2010-07-17)
  1242. first public release
  1243. 0.90 first internal release
  1244. */
  1245. /*
  1246. ------------------------------------------------------------------------------
  1247. This software is available under 2 licenses -- choose whichever you prefer.
  1248. ------------------------------------------------------------------------------
  1249. ALTERNATIVE A - MIT License
  1250. Copyright (c) 2017 Sean Barrett
  1251. Permission is hereby granted, free of charge, to any person obtaining a copy of
  1252. this software and associated documentation files (the "Software"), to deal in
  1253. the Software without restriction, including without limitation the rights to
  1254. use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  1255. of the Software, and to permit persons to whom the Software is furnished to do
  1256. so, subject to the following conditions:
  1257. The above copyright notice and this permission notice shall be included in all
  1258. copies or substantial portions of the Software.
  1259. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  1260. IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  1261. FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  1262. AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  1263. LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  1264. OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  1265. SOFTWARE.
  1266. ------------------------------------------------------------------------------
  1267. ALTERNATIVE B - Public Domain (www.unlicense.org)
  1268. This is free and unencumbered software released into the public domain.
  1269. Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
  1270. software, either in source code form or as a compiled binary, for any purpose,
  1271. commercial or non-commercial, and by any means.
  1272. In jurisdictions that recognize copyright laws, the author or authors of this
  1273. software dedicate any and all copyright interest in the software to the public
  1274. domain. We make this dedication for the benefit of the public at large and to
  1275. the detriment of our heirs and successors. We intend this dedication to be an
  1276. overt act of relinquishment in perpetuity of all present and future rights to
  1277. this software under copyright law.
  1278. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  1279. IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  1280. FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  1281. AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  1282. ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  1283. WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  1284. ------------------------------------------------------------------------------
  1285. */